JP2014091338A - Vehicle travel control device - Google Patents

Abstract

The present invention provides a vehicle travel control device that can achieve both improvement in vehicle fuel efficiency and suppression of brake pad wear.
Neutral inertia traveling, cylinder deactivation inertia, and engine braking traveling with different magnitudes of deceleration due to engine braking can be selected in accordance with the engine braking force required during traveling. For this reason, when a moderate engine braking force between the neutral inertia traveling and the engine braking traveling is necessary, the cylinder deactivation inertia traveling can be performed. Compared to the conventional case where engine braking is performed uniformly, the deceleration is reduced and fuel consumption is improved. In addition, compared with the case where neutral inertia traveling is performed when the moderate engine braking force is required, the above deceleration is larger in cylinder idle inertia traveling than in neutral inertia traveling. Can be suppressed.
[Selection] Figure 1

Description

  The present invention relates to a vehicle travel control device, and more particularly, to a vehicle capable of coasting traveling with a lower engine braking force than engine braking traveling, and improving the fuel consumption of the vehicle during the coasting and a brake pad. The present invention relates to a technology that achieves both wear suppression.

  Compared to normal driving (engine braking driving) where the engine brake is applied by the driven rotation of the engine while the power transmission between the engine and driving wheels is connected, the driving distance is extended and the fuel efficiency of the vehicle is improved. In order to do this, inertial running is considered in which the engine braking force is reduced as compared with the normal running. The device described in Patent Document 1 is an example thereof, and when a return operation of the accelerator pedal is determined during traveling of the vehicle, a clutch provided in a power transmission path between the engine and the drive wheels is released to inertia. Driving is started and the fuel efficiency of the vehicle is improved.

Japanese Patent Application Laid-Open No. 2002-227885

  By the way, in patent document 1, when the driver is going to decelerate the vehicle, the control of the inertia traveling is stopped and the control is returned to the normal traveling control. As a means for determining the driver's intention to decelerate the vehicle, for example, a determination may be made based on whether or not a brake pedal depression amount greater than a predetermined level is detected.

  However, in the method of Patent Document 1, for example, when the fuel consumption is emphasized, and the threshold for the brake depression amount is increased to increase the inertial running area, for example, moderate deceleration deceleration is required during driving. In some cases, in inertial running, the deceleration due to the engine brake is very small compared to the normal running, so that the region where the deceleration is output by the brake increases, and the wear of the brake pad is significantly larger than in the normal running. It may be faster. On the other hand, if the threshold of the brake depression amount is reduced in consideration of the wear suppression of the brake pad to reduce the inertia running area, the deceleration due to the engine brake during driving increases and the fuel consumption of the vehicle deteriorates. There may be a problem.

  The present invention has been made against the background of the above circumstances, and an object of the present invention is to provide a vehicle travel control device capable of achieving both improvement in vehicle fuel efficiency and suppression of brake pad wear. .

  In order to achieve such an object, the gist of the present invention is that: (a) an engine having a plurality of cylinders, a clutch device for separating the engine and drive wheels, and means for determining the necessity of engine braking; (B) a travel control device for a vehicle that performs normal travel that travels by connecting the engine and the drive wheels, and neutral inertia travel that travels by separating the engine and the drive wheels, (c) The vehicle further includes a cylinder deactivation inertia traveling in which the engine and the driving wheel are coupled to deactivate at least some of the cylinders of the engine, and (d) an engine of the traveling vehicle The deceleration due to the brake has characteristics that are large in the order of the neutral inertia traveling, the cylinder resting inertia traveling, and the normal traveling, and (e) the neutral inertia traveling and the cylinder resting inertia. Line, the need for the engine brake in the order of the normal running is selected when increased.

  According to the vehicle traveling control apparatus configured as described above, the vehicle performs cylinder deactivation inertia traveling in which the engine and the drive wheels are coupled to each other while at least some of the cylinders of the engine are deactivated. Further, the deceleration due to the engine brake of the traveling vehicle has characteristics that are in the order of the neutral inertia traveling, the cylinder resting inertia traveling, and the normal traveling in the order of the neutral inertia traveling, the cylinder resting inertia traveling, It is selected when the necessity of the engine brake increases in the order of the normal running. Therefore, the neutral inertia traveling, the cylinder deactivation inertia traveling, and the normal traveling, each of which has a different magnitude of deceleration due to the engine brake, can be selected according to the engine braking force required during traveling. As a result, the cylinder deactivation inertia traveling can be carried out when a moderate engine braking force between the neutral inertia traveling and the normal traveling is required. Therefore, as compared with the conventional case where the inertia traveling is uniformly stopped when the engine braking force is required and the normal traveling is performed, the deceleration by the engine brake is reduced, so that the fuel consumption of the vehicle is improved. Can do. In addition, when the neutral engine braking force is required, the deceleration due to the engine brake is larger in the cylinder idle inertia traveling than in the neutral inertia traveling. Therefore, wear of the brake pad can be suppressed. As a result, it is possible to achieve both improvement in vehicle fuel efficiency and suppression of brake pad wear.

  Here, it is preferable that the means for determining the necessity of the engine brake determines the necessity of the engine brake according to any one of a depression of a brake pedal, a road surface gradient, and a distance from a preceding vehicle. For this reason, the necessity of the engine brake at the time of traveling can be suitably predicted by depressing the brake pedal, the gradient of the road surface, and the distance to the preceding vehicle.

  Preferably, (a) the necessity of the engine brake is a magnitude of deceleration required during traveling, and (b) a stepping on the brake pedal in the means for determining the necessity of the engine brake. When the magnitude of the required deceleration is determined by the above, a braking force is issued so that the required deceleration is achieved by the engine brake of the vehicle and the foot brake by depressing the brake pedal. (C) The braking force generated by the foot brake is larger than the braking force generated by the engine brake. For this reason, since the required deceleration is not compensated by the braking force generated only by the engine brake by depressing the brake pedal, the wheel brake provided on the drive wheel in the foot brake is used at a low pressure. This prevents the wheel from squeaking from the wheel brake.

  Preferably, (a) the upper limit value of the engine brake necessary to perform the cylinder idle inertia traveling is set to be larger than the upper limit value of the engine brake necessary to perform the neutral inertia traveling. (B) The upper limit value of the necessity of the engine brake for performing the normal traveling is set larger than the upper limit value of the necessity of the engine brake for performing the cylinder deactivation inertia traveling. Therefore, the neutral inertia traveling, the cylinder deactivation inertia traveling, and the normal traveling, each having a different magnitude of deceleration by the engine brake, can be appropriately selected according to the engine braking force required during traveling.

  Preferably, (a) during the neutral inertia traveling, the neutral inertia traveling is terminated when the necessity of the engine brake becomes greater than an upper limit value of the necessity of the engine brake for performing the neutral inertia traveling. (B) During the cylinder deactivation inertia traveling, when the necessity of the engine brake becomes larger than the upper limit value of the engine brake necessity for performing the cylinder deactivation inertia traveling, The cylinder resting inertia traveling is terminated and the normal traveling is performed. For this reason, the neutral inertia traveling, the cylinder deactivation inertia traveling, and the normal traveling, each having a different magnitude of deceleration due to the engine brake, are appropriately selected according to the engine braking force required during traveling.

  Preferably, the neutral coasting is operated by coasting to stop the fuel supply to the engine and stop the rotation while the engine and the driving wheel are separated from each other or by supplying fuel to the engine. It is coasting. For this reason, for example, in the neutral coasting, when the fuel supply to the engine is stopped and the rotation is stopped, the fuel efficiency of the vehicle is preferably improved.

  Preferably, the present invention can be applied to a vehicle including at least an engine as a driving force source. For example, the present invention is preferably applied to a vehicle in which engine power is transmitted to driving wheels via an automatic transmission. However, the present invention can also be applied to a hybrid vehicle including an electric motor or a motor generator as a driving force source in addition to the engine. The engine is an internal combustion engine that generates power by burning fuel.

  Preferably, a clutch device for connecting and disconnecting a power transmission path between the engine and the drive wheels is disposed between the engine and the drive wheels so that the engine can be disconnected from the drive wheels. . As this clutch device, a hydraulic friction engagement device provided in series in the power transmission path, for example, a hydraulic clutch, is preferably used. However, it is also possible to electrically control the reaction force to cut off the power transmission. Various types of clutches can be employed. It is also possible to use a forward clutch in an automatic transmission that includes a plurality of clutches and brakes and can shift to a plurality of stages. The clutch device for connecting and disconnecting the power transmission path includes, for example, a planetary gear device having a pair of rotating elements connected to the power transmission path inserted in the power transmission path, and the planetary gear device. You may be comprised from the hydraulic brake which blocks | prevents rotation of the other rotation element which is not connected to the power transmission path | route among rotation elements. When the automatic transmission is a belt type continuously variable transmission, a forward friction engagement device and a reverse friction engagement device of a forward / reverse switching mechanism provided in the automatic transmission are used as a clutch device. Further, when the automatic transmission is a parallel-shaft always-mesh transmission, the sleeve of the synchronization mechanism provided in the automatic transmission and the actuator that drives the synchronous mechanism correspond to the clutch device.

  Preferably, the starting conditions for the neutral inertia traveling and the cylinder deactivation inertia traveling are, for example, a power transmission path from the engine to the drive wheels is connected by a clutch, and the shift stage of the automatic transmission is a predetermined high speed side shift. That is, the accelerator pedal is operated to return to the original position or a position close to the original position in a relatively high speed steady traveling state in which the vehicle speed V is set to the forward speed or higher and the vehicle speed V is equal to or higher than the predetermined vehicle speed V1.

It is the schematic block diagram which showed together the principal part of the control function of an electronic control unit in the outline figure of the vehicle drive device to which this invention is applied suitably. It is a figure explaining three driving | running | working relevant to this invention among the driving | running | working performed by the vehicle drive device of FIG. FIG. 3 is a diagram showing a state in which the fuel injection amount is controlled by the neutral inertia traveling section of the electronic control unit of FIG. 1 in order to keep the vehicle speed in a predetermined vehicle speed range in the neutral inertia traveling of FIG. 2. FIG. 3 is a diagram showing a state in which the fuel injection amount is controlled by a cylinder deactivation inertia traveling unit of the electronic control unit of FIG. 1 in order to keep the vehicle speed in a predetermined vehicle speed range in the cylinder deactivation inertia traveling of FIG. 2. FIG. 3 is a diagram showing a state in which the fuel injection amount is controlled by a normal traveling unit of the electronic control unit of FIG. 1 in order to keep the vehicle speed in a predetermined vehicle speed range in the engine brake traveling of FIG. 2. It is a figure explaining the brake depression amount determination part provided in the electronic controller of FIG. 1, and is a figure showing a state where the brake depression amount of the brake pedal is between zero and a predetermined depression amount determination value Bα. is there. It is a figure explaining the brake depression amount determination part provided in the electronic controller of FIG. 1, and the brake depression amount of the brake pedal is a predetermined depression amount determination value Bα and a predetermined depression amount determination value Bβ. It is a figure which shows the state in between. It is a figure explaining the brake depression amount determination part provided in the electronic controller of FIG. 1, and is a figure which shows the state in which the brake depression amount of a brake pedal is larger than the predetermined depression amount determination value Bβ. N range coasting control (neutral coasting traveling), valve stop free-run control (cylinder rest coasting traveling), fuel cut control performed in relation to the brake depression amount of the brake pedal in the coasting traveling switching control of the electronic control device of FIG. It is a figure explaining the relationship with (engine brake driving | running | working). The electronic control unit shown in FIG. 1 determines whether to perform neutral inertia traveling, cylinder deactivation inertia, and engine brake traveling, and based on the determination, any one of these neutral inertia traveling, cylinder deactivation inertia traveling, or engine brake traveling is performed. It is a flowchart explaining the control action which implements. It is a time chart corresponding to the control action of FIG. It is a figure which shows the electronic controller of the vehicle drive device which shows the other Example of this invention, and is a figure corresponding to FIG. It is a figure which shows the distance between vehicles with a front vehicle in the distance determination part provided in the electronic controller of FIG. The electronic control unit shown in FIG. 12 determines whether to execute neutral inertia traveling, cylinder deactivation inertia, or engine brake traveling, and based on the determination, any one of the neutral inertia traveling, cylinder deactivation inertia traveling, or engine brake traveling is performed. It is a flowchart explaining the control action which implements. It is a time chart corresponding to the control action of FIG. It is a figure which shows the electronic controller of the vehicle drive device which shows the other Example of this invention, and is a figure corresponding to FIG. 1 and FIG. It is a figure which shows the downward gradient of a road surface in the downward gradient determination part provided in the electronic controller of FIG. The electronic control unit shown in FIG. 16 determines whether to perform neutral inertia traveling, cylinder deactivation inertia, or engine brake traveling, and based on the determination, any one of the neutral inertia traveling, cylinder deactivation inertia traveling, or engine brake traveling is performed. It is a flowchart explaining the control action which implements. It is a time chart corresponding to the control action of FIG.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a schematic configuration diagram illustrating a main part of a control function of an electronic control device 50 corresponding to a travel control device in a vehicle drive device 10 to which the present invention is preferably applied. The vehicle drive device 10 includes an engine 12 that is an internal combustion engine such as a gasoline engine or a diesel engine that generates power by combustion of fuel as a driving force source, and the output of the engine 12 is differential from the automatic transmission 16. It is transmitted to the left and right drive wheels 20 via the gear unit 18. A power transmission device such as a damper device or a torque converter can be provided between the engine 12 and the automatic transmission 16, but a motor generator that functions as a driving force source can also be provided.

  The engine 12 includes an engine control device 30 having various devices necessary for output control of the engine 12, such as an electronic throttle valve and a fuel injection device, a cylinder deactivation device, and the like. The electronic throttle valve controls the intake air amount, and the fuel injection device controls the fuel supply amount. Basically, the operation amount of the accelerator pedal 68 corresponding to the driver's output demand amount, that is, the accelerator opening amount. It is controlled according to the degree θacc. The fuel injection device can stop fuel supply (fuel cut F / C) even when the vehicle is traveling, such as when the accelerator opening θacc is 0 and the accelerator is OFF. The cylinder deactivation device is capable of mechanically separating and stopping some or all of the intake and exhaust valves of a plurality of cylinders such as eight cylinders from the crankshaft by a clutch mechanism or the like. Is stopped so as to be in a closed state or an open state. As a result, the pumping loss when the engine 12 is driven and rotated in the fuel cut state is reduced, and the engine braking force is reduced, so that the traveling distance of inertial traveling can be extended. Instead of stopping the intake / exhaust valve, the piston may be separated from the crankshaft and stopped.

  The automatic transmission 16 is, for example, a stepped automatic transmission such as a planetary gear type in which a plurality of gear stages having different gear ratios e are established depending on the disengagement state of a plurality of hydraulic friction engagement devices (clutch and brake). The shift control is performed by an electromagnetic hydraulic control valve, a switching valve or the like provided in the hydraulic control device 32. The clutch (clutch device) C1 functions as an input clutch of the automatic transmission 16, and is similarly engaged and released by the hydraulic control device 32. The clutch C1 corresponds to a connection / disconnection clutch that connects or disconnects the power transmission path between the engine 12 and the drive wheels 20. As the automatic transmission 16, a parallel shaft constantly meshing stepped transmission or a belt-type continuously variable transmission with a forward / reverse switching gear mechanism may be used. In the case of a parallel shaft type continuously meshing stepped transmission, the power transmission path is released by releasing the meshing of the synchronous meshing device using an actuator, and in the case of a continuously variable transmission, its forward / reverse switching gear The power transmission path is released by releasing the forward and reverse friction engagement devices provided in the mechanism.

  The driving wheel 20 is provided with a wheel brake 34, and a braking force is generated according to the brake operation force (stepping force) of the brake pedal 40 that is stepped on by the driver. The brake operating force corresponds to the required brake amount. In this embodiment, the brake hydraulic pressure is mechanically generated from the brake master cylinder 44 via the brake booster 42 in accordance with the brake operating force, and the braking hydraulic pressure causes the braking force. Is generated. The brake booster 42 amplifies the brake operation force by using the brake negative pressure (negative pressure) generated by the rotation of the engine 12, and the brake hydraulic pressure output from the brake master cylinder 44 is amplified to increase the braking force. Can be obtained. The wheel brake 34 is electrically controlled in accordance with a brake control signal output from the electronic control unit 50.

  The vehicle drive device 10 configured as described above includes an electronic control device 50. The electronic control unit 50 includes a so-called microcomputer having a CPU, a ROM, a RAM, an input / output interface, and the like, and performs signal processing according to a program stored in advance in the ROM while using a temporary storage function of the RAM. Do. The electronic control device 50 is supplied with a signal indicating the brake depression amount B when the brake pedal 40 is depressed from the brake depression amount sensor 64 and the accelerator opening amount that is the operation amount of the accelerator pedal 68 from the accelerator operation amount sensor 66. A signal representing the degree θacc (%) is supplied. Further, a signal representing the rotational speed NE (rpm) of the engine 12 is supplied from the engine rotational speed sensor 70, and a signal representing the vehicle speed V (km / h) is supplied from the vehicle speed sensor 72. In addition, various types of information necessary for various types of control are supplied.

  The electronic control unit 50 performs output control and rotation stop control of the engine 12 in accordance with the accelerator opening θacc corresponding to the driver's intention to accelerate and the amount of brake operation, and a driver's Based on the required output based on the accelerator opening θacc corresponding to the intention to accelerate, or on the basis of the accelerator opening θacc and the vehicle speed V, the shift control for controlling the shift stage of the automatic transmission 16 is executed. In the inertial traveling state in which the accelerator opening degree θacc is zero, the automatic transmission 16 is established with a predetermined gear stage exclusively according to the vehicle speed V and the like, and the clutch C1 is held in the engaged state. In this engine brake traveling, the engine 12 is driven to rotate at a predetermined rotational speed determined according to the vehicle speed V and the gear ratio e, and an engine braking force having a magnitude corresponding to the rotational speed is generated. Further, since the engine 12 is driven and rotated at a predetermined rotational speed, the brake operation force can be appropriately amplified by the brake booster 42 using the brake negative pressure generated by the engine rotation, and the brake operation can be performed. Sufficient braking force control performance can be obtained.

  In addition, the electronic control device 50 includes a normal traveling unit 52, a cylinder deactivation inertia traveling unit 54, a neutral inertia traveling unit 56, an inertia traveling desire determination unit 58, and an inertia traveling switching control unit 60 having a brake depression amount determination unit 60. Part 62 and the like. The normal travel unit 52 performs normal travel that travels by connecting the power transmission path between the engine 12 and the drive wheels 20 by engaging the clutch C1. Note that the normal traveling unit 52 performs engine brake traveling in which engine braking occurs due to pumping loss, friction torque, and the like due to driven rotation of the engine 12 as shown in FIG. 2 when the accelerator is OFF. The normal traveling unit 52 performs fuel cut control for stopping the fuel supply to the engine 12 while the engine 12 and the drive wheel 20 are connected during the engine brake traveling.

  The cylinder deactivation inertia traveling unit 54 stops the fuel supply to the engine 12 in a state where the power transmission path between the engine 12 and the drive wheels 20 is connected when the accelerator pedal 68 is returned, and the cylinder deactivation device uses the cylinder deactivation device to stop the engine 12. The cylinder stop inertia running is performed by performing the valve stop free-run control for stopping the operation of at least one of the pistons and intake / exhaust valves of some of the cylinders. In the cylinder deactivation inertia traveling, since the pumping loss is reduced by the cylinder deactivation device when the engine 12 is driven to rotate in the fuel cut state, the engine braking force is reduced compared to the engine braking traveling, and the inertia traveling is performed. The mileage due to becomes longer.

  The neutral coasting travel unit 56 performs N range coasting control to release the clutch C1 while maintaining the rotation of the engine 12 during coasting without performing the fuel cut F / C when the accelerator pedal 68 is returned. Perform inertial running. In the neutral inertia traveling, since the clutch C1 is released, the engine braking force becomes substantially zero and the engine braking force becomes smaller than that of the cylinder resting inertia traveling. It becomes even longer than cylinder idle coasting.

  3 to 5 show a neutral inertia traveling unit 56, a cylinder deactivation inertia traveling unit 54, in order to keep the vehicle speed V in a predetermined vehicle speed range in each of the neutral inertia traveling, the cylinder deactivation inertia traveling, and the engine brake traveling. It is a figure which shows the state which is controlling the fuel injection quantity by the normal driving | running | working part. 3 shows the state during the neutral inertia running, FIG. 4 shows the state during the cylinder resting inertia running, and FIG. 5 shows the state during the engine brake running. .

  As shown in FIG. 3, in the neutral inertia running, the clutch C1 is released and the engine braking force is substantially zero. Therefore, the deceleration by the engine brake is very small and the vehicle speed V is maintained in a predetermined vehicle speed range. There is almost no need to increase the fuel injection amount for acceleration. Further, as shown in FIG. 4, in the cylinder resting inertia traveling, the clutch C1 is engaged, so that the engine braking force is larger than that in the neutral inertia traveling and the deceleration due to the engine brake is larger than that in the neutral inertia traveling. Therefore, it is necessary to increase the fuel injection amount in order to keep the vehicle speed V in a predetermined vehicle speed range, that is, to accelerate again. Further, as shown in FIG. 5, in the engine brake travel, the pumping loss is reduced when the engine C12 is engaged and the engine 12 is driven and rotated by the cylinder deactivation device as in the cylinder deactivation inertia traveling. It has not been. For this reason, the engine braking force is larger than that in the cylinder deactivation inertia traveling, and the deceleration due to the engine brake is larger than that in the cylinder deactivation inertia traveling. Therefore, in order to maintain the vehicle speed V in a predetermined vehicle speed range, the fuel injection amount is It is necessary to further increase compared to cylinder idle inertia running. That is, the magnitude relationship between the deceleration by the engine brake during each travel is as follows: engine brake travel (fuel cut control)> cylinder deactivation inertia travel (valve stop free run control)> neutral inertia travel (N range coasting) Control). Further, the magnitude relationship of the fuel efficiency effect during each travel is as follows: neutral inertia travel> cylinder idle inertia travel> engine brake travel. In the present embodiment, the engine brake is a brake generated in the vehicle based on running resistance when the accelerator pedal 68 and the brake pedal 40 are not operated.

  The inertial travel desire determination unit 58 is configured such that, for example, a power transmission path from the engine 12 to the drive wheel 20 is connected by the clutch C1, and the shift stage of the automatic transmission 16 is set to a forward speed greater than a predetermined high speed side shift stage Further, in a relatively high speed steady driving state where the vehicle speed V (km / h) is equal to or higher than a predetermined value, it is determined whether or not the driver desires inertia driving depending on, for example, whether or not the accelerator pedal 68 is turned off. .

  The brake depression amount determination unit 60 determines whether or not the brake depression amount B detected by the brake depression amount sensor 64 is larger than a preset depression amount determination value Bα, and the brake depression amount detected by the brake depression amount sensor 64. It is determined whether or not B is larger than a preset depression amount determination value Bβ. That is, the brake depression amount determination unit 60 determines that the brake depression amount B detected by the brake depression amount sensor 64 is 0 <B ≦ Bα as shown in FIG. 6, or Bα <B as shown in FIG. It is determined whether ≦ Bβ or Bβ <B as shown in FIG. 6 to 8, the broken brake pedal 40 indicates a state before the brake pedal 40 is depressed by the driver.

  The stepping amount determination value Bα is an upper limit value of the brake stepping amount B set in advance by, for example, an experiment for performing the cylinder resting inertia running, and the stepping amount determination value Bβ performs the engine brake traveling. For example, the upper limit value of the brake depression amount B set in advance by experiment or the like, the depression amount determination value Bβ is larger than the depression amount determination value Bα, and the depression amount determination values Bα and Bβ are larger than 0 (0 <Bα < Bβ) is set. Note that the depression amount determination values Bα and Bβ, which are the upper limit values of the brake depression amount B set in advance, are upper limit values of the magnitude of deceleration caused by the engine brake required during traveling, that is, the necessity of the engine brake. This corresponds to the upper limit value. For example, as the depression amount determination values Bα and Bβ increase, the upper limit value of the magnitude of deceleration by the engine brake required during traveling, that is, the upper limit value of the necessity of the engine brake increases. It has become.

  In this embodiment, the brake depression amount B predicts the amount of deceleration caused by the engine brake required by the driver during traveling, that is, indicates the necessity of the engine brake. As B increases, the deceleration by the engine brake required by the driver increases, and the necessity of the engine brake increases. The stepping amount determination values Bα and Bβ are determination values for determining the degree of necessity of the engine brake. If the brake stepping amount B is equal to or smaller than the stepping amount determination value Bα, the driver is required when traveling. The magnitude of deceleration due to engine braking is small and the need for engine braking is reduced. If the brake depression amount B is greater than the depression amount determination value Bα and less than or equal to the depression amount determination value Bβ, the magnitude of deceleration caused by the engine brake required by the driver during traveling is large and the necessity of the engine brake is increased. . If the brake depressing amount B is larger than the depressing amount determination value Bβ, the amount of deceleration of the engine brake required by the driver during driving is such that the brake depressing amount B is larger than the depressing amount determination value Bα. The need for the engine brake is even greater compared to: That is, the brake depression amount determination unit 60 is a means for determining the magnitude of necessity of the engine brake while the vehicle is traveling.

  The inertial travel switching control unit 62 determines that the accelerator pedal 68 is in the OFF state by the inertial travel desire determination unit 58, and the brake depression amount determination unit 60 determines that the brake depression amount B is equal to or less than the depression amount determination value Bα. As shown in FIG. 6, when it is determined that the brake depression amount B is within the range of 0 <B ≦ Bα, the neutral inertia traveling unit 56 performs neutral inertia traveling.

  In addition, the inertial travel switching control unit 62 determines that the accelerator pedal 68 is in the OFF state by the inertial travel desire determination unit 58, and the brake depression amount determination unit 60 determines that the brake depression amount B is larger than the depression amount determination value Bα. When it is determined that the brake depression amount B is equal to or less than the depression amount determination value Bβ, that is, as shown in FIG. 7, within the range of Bα <B ≦ Bβ, the cylinder deactivation inertia traveling unit 54 performs the cylinder deactivation inertia traveling.

  In addition, the inertial travel switching control unit 62 determines that the accelerator pedal 68 is in the OFF state by the inertial travel desire determination unit 58, and the brake depression amount determination unit 60 determines that the brake depression amount B is greater than the depression amount determination value Bβ. That is, as shown in FIG. 8, when it is determined that the brake depression amount B is within the range of Bβ <B, the normal traveling unit 52 performs engine brake traveling.

The conditions for executing the neutral inertia traveling, the cylinder deactivation inertia traveling, and the engine brake traveling with respect to the brake depression amount B are as follows. The brake depression for performing the cylinder deactivation inertia traveling (valve stop free-run control) as shown in FIG. The amount B depression amount judgment value (upper limit value) Bβ is set larger than the stepping amount judgment value (upper limit value) Bα of the brake depression amount B for performing the neutral inertia running (N range coasting control) (Va <Vb). Has been. Further, the depression amount determination value (upper limit value) B _{MAX of} the brake depression amount B that performs the engine brake traveling (fuel cut control) is the depression amount determination value (upper limit) of the brake depression amount B that performs the cylinder deactivation inertia traveling. (Value) larger than Bβ (B _MAX <Bβ). Therefore, when the brake depression amount B is equal to or less than the depression amount determination value Bα, the neutral inertia traveling can be performed, and the brake depression amount B is larger than the depression amount determination value Bα and equal to or less than the depression amount determination value Bβ. In some cases, the cylinder deactivation inertia traveling can be performed, and when the brake depression amount B is larger than the depression amount determination value Bβ, the engine brake traveling can be performed. The depression amount determination value B _MAX indicates the maximum brake depression amount B when the brake pedal 40 is depressed.

  Further, for example, as shown in FIG. 9A, a lower limit value (for example, Bα) of the brake depression amount B for performing the cylinder resting inertia traveling and an upper limit value (for example, Bα of the brake depression amount B for performing the neutral inertia traveling). For example, Bα) is set to the same value, or the lower limit value (for example, Bβ) of the brake depression amount B for executing the engine brake travel and the upper limit value (for example, Bβ) of the brake depression amount B for performing the cylinder deactivation inertia traveling. Can be set to the same value. As a result, the inertial travel switching control unit 62 terminates the neutral inertial travel when the brake depression amount B becomes larger than the stepped amount determination value Bα during the neutral inertial travel, and the cylinder deactivation inertial traveling unit 54 terminates the cylinder deactivation. Carry out inertial running. Further, when the brake depression amount B becomes larger than the depression amount determination value Bβ during the cylinder deactivation inertia traveling, the cylinder deactivation inertia traveling is terminated and the engine braking operation is performed by the normal traveling section 52. Further, the inertial travel switching control unit 62 terminates the engine brake travel and performs the cylinder deactivation inertia when the brake depression amount B becomes equal to or smaller than the depression amount determination value Bβ during the engine brake travel, If the brake depression amount B is equal to or less than the depression amount determination value Bα during the rest inertia running, the cylinder rest inertia running is terminated and the neutral inertia running is performed. Further, as shown in FIG. 9B, a lower limit value (for example, 0) of the brake depression amount B for executing the neutral inertia traveling and a lower limit value (for example, 0) of the brake depression amount B for performing the cylinder resting inertia traveling. ) And a lower limit value (for example, 0) of the brake depression amount B at which the engine brake travel is performed can be set to the same value.

  The inertial travel switching control unit 62 is, for example, an engine when the inertial travel desire determination unit 58 is out of at least one of the above-described relatively high-speed steady travel state determination conditions and / or when a brake operation is performed. In order to switch to the brake traveling or another traveling mode, the neutral inertia traveling and the cylinder deactivation inertia traveling are terminated.

  In the electronic control unit 50 of the present embodiment, when the brake depression amount sensor 64 detects the brake depression amount B and determines the magnitude of deceleration by the engine brake requested by the driver, the brake depression amount is detected. Based on the amount B, the inertia traveling switching control unit 62 performs any one of the neutral inertia traveling, the cylinder deactivation inertia traveling, and the engine brake traveling, and the wheel brake 34 by depressing the engine brake and the brake pedal 40; Thus, the braking force is output so as to achieve the required deceleration. In the electronic control unit 50, for example, the braking force generated by the wheel brake 34 is controlled to be larger than the braking force generated by the engine brake.

  FIG. 10 illustrates a brake depression amount determination unit 60 that determines whether the neutral inertia traveling, the cylinder deactivation inertia traveling, or the engine brake traveling is performed by the essential control operation of the electronic control unit 50, that is, the inertia traveling switching control unit 62. It is a flowchart explaining the control action which is performed based on this determination and performs one of those traveling. FIG. 11 is a time chart corresponding to the main part of the control operation of the electronic control unit 50 of FIG.

  In FIG. 10, in step S <b> 1 (hereinafter, step is omitted) corresponding to the inertial travel desire determination unit 58, it is determined whether or not the accelerator pedal 68 is in an OFF state in the relatively high speed steady travel state. . When the determination of S1 is negative, S1 is repeatedly executed. However, for example, when the depression of the accelerator pedal 68 is turned off as shown at time t1 in FIG. 11, the determination of S1 is affirmed. S2 corresponding to the brake depression amount determination unit 60 is executed.

  In S2, it is determined whether or not the brake depression amount B of the brake pedal 40 is larger than the depression amount determination value Bα, that is, whether or not the necessity of the engine brake is relatively large and the brake performance is important. Then, in S2, for example, as shown between t2 and t3 in FIG. 11, if it is determined that the brake depression amount B is equal to or less than the depression amount determination value Bα and the brake performance is not important, the determination in S2 is negative. Then, in S3 corresponding to the inertial traveling switching control unit 62 and the neutral inertial traveling unit 56, the N-range coasting control is performed and the neutral inertial traveling is performed.

  Further, during the neutral inertia traveling, for example, when the brake depression amount B becomes larger than the depression amount determination value Bα as shown between t3 and t4 in FIG. 11, it is determined in S2 that the braking performance is important. That is, the determination in S2 is affirmed and S4 corresponding to the brake depression amount determination unit 60 is executed. In S4, whether or not the brake depression amount B of the brake pedal 40 is larger than the depression amount determination value Bβ, that is, the necessity of the engine brake is larger than that at S2, and the brake performance is more important than at S2. It is determined whether or not. Then, when it is determined in S4 that the brake depression amount B is equal to or less than the depression amount determination value Bβ as shown between t3 and t4 in FIG. If the determination is negative, the valve stop free-run control is performed in S5 corresponding to the inertia traveling switching control unit 62 and the cylinder deactivation inertia traveling unit 54, and the cylinder deactivation inertia traveling is performed.

  In addition, during the cylinder resting inertia traveling, for example, as shown after t4 in FIG. 11, when the brake depression amount B becomes larger than the depression amount determination value Bβ, it is determined in S4 that the above-described brake performance is emphasized. That is, the determination in S4 is affirmed, fuel cut control is performed in S6 corresponding to the inertia traveling switching control unit 62 and the normal traveling unit 52, and engine braking traveling is performed.

  As described above, according to the electronic control device 50 provided in the vehicle drive device 10 of the present embodiment, the vehicle has at least some cylinders of the engine 12 in a state where the engine 12 and the drive wheels 20 are connected. The cylinder braking inertia traveling that travels while stopping, and the deceleration by the engine brake of the traveling vehicle has large characteristics in the order of the neutral inertia traveling, the cylinder resting inertia traveling, and the engine brake traveling. It is selected when the necessity of the engine brake increases in the order of the neutral inertia traveling, the cylinder deactivation inertia traveling, and the engine brake traveling. For this reason, the inertial travel switching control unit 62 having the brake depression amount determination unit 60 performs the neutral inertial travel, the cylinder deactivation inertial travel, and the engine brake travel, each of which has a different magnitude of deceleration due to the engine brake. It can be selected according to the required engine braking force. As a result, when the brake depression amount determination unit 60 determines that the magnitude of the deceleration by the engine brake requires an intermediate engine braking force between the neutral inertia traveling and the engine braking traveling, the inertia The cylinder switching inertia traveling can be performed by the traveling switching control unit 62. As a result, the deceleration by the engine brake is reduced and the fuel consumption of the vehicle is improved as compared with the conventional case where the inertia braking is uniformly stopped when the engine braking force is required and the engine braking is performed. be able to. In addition, when the neutral engine braking force is required, the deceleration due to the engine brake is larger in the cylinder idle inertia traveling than in the neutral inertia traveling. Therefore, wear of the brake pad can be suppressed. As a result, it is possible to achieve both improvement in vehicle fuel efficiency and suppression of brake pad wear.

  Further, according to the electronic control device 50 provided in the vehicle drive device 10 of the present embodiment, the brake depression amount determination unit 60 determines the necessity of the engine brake based on the brake depression amount B of the brake pedal 68. . For this reason, the necessity of the engine brake at the time of traveling can be suitably predicted from the brake depression amount B.

  Further, according to the electronic control device 50 provided in the vehicle drive device 10 of the present embodiment, the necessity of the engine brake is the magnitude of the deceleration required during traveling, and the brake depression amount determination unit When the required amount of deceleration due to the engine brake is determined based on the brake depression amount B of the brake pedal 40 at 60, the required amount is requested by the engine brake of the vehicle and the wheel brake 34 due to depression of the brake pedal 40. A braking force is generated so as to achieve deceleration, and the braking force generated by the wheel brake 34 is larger than the braking force generated by the engine brake. For this reason, since the required deceleration by the engine brake is not compensated by the braking force generated only by the engine brake by the brake depression amount B of the brake pedal 40, the wheel brake 34 may be used at a low pressure. Thus, the brake noise from the wheel brake 34 is prevented.

Further, according to the electronic control unit 50 provided in the vehicle drive device 10 of the present embodiment, the stepping amount determination value Bβ of the brake stepping amount B for performing the cylinder deactivation inertia traveling performs the neutral inertia traveling. The brake depression amount B is set to be larger than the depression amount determination value Bα, and the depression amount determination value B _MAX of the brake depression amount B that performs the engine brake traveling is the brake depression amount B that performs the cylinder deactivation inertia traveling. It is set larger than the depression amount determination value Bβ. For this reason, the inertial travel switching control unit 62 having the brake depression amount determination unit 60 performs the neutral inertial travel, the cylinder deactivation inertial travel, and the engine brake travel, each of which has a different magnitude of deceleration due to the engine brake. It can be appropriately selected according to the required engine braking force.

  Further, according to the electronic control device 50 provided in the vehicle drive device 10 of the present embodiment, the brake depression amount B during the neutral inertia traveling by the inertia traveling switching control unit 62 having the brake depression amount determination unit 60. Is greater than the depression amount determination value Bα of the brake depression amount B at which the neutral inertia traveling is performed, the neutral inertia traveling is terminated and the cylinder deactivation inertia traveling is performed. During the cylinder deactivation inertia traveling, the brake depression amount When B becomes larger than the depression amount determination value Bβ of the brake depression amount B for performing the cylinder deactivation inertia traveling, the cylinder deactivation inertia traveling is terminated and the engine brake traveling is performed. For this reason, the neutral inertia traveling, the cylinder deactivation inertia traveling, and the engine brake traveling, which have different magnitudes of deceleration due to the engine brake, are appropriately selected according to the engine braking force required during traveling.

  Next, another embodiment of the present invention will be described in detail based on the drawings. In the following description, parts common to the embodiments are denoted by the same reference numerals and description thereof is omitted.

  As shown in FIG. 12, an electronic control device (running control device) 74 of the vehicle drive device 10 of the present embodiment is provided with a brake provided with the electronic control device 50 as compared with the electronic control device 50 of the first embodiment. The difference is that the stepping amount determination unit 60 is replaced with an inter-vehicle distance determination unit 76, and the others are substantially the same as the electronic control device 50 of the first embodiment. Further, as shown in FIG. 12 and FIG. 13, the vehicle drive device 10 receives a signal indicating an inter-vehicle distance (distance) D from the front vehicle 82 by a front radar 80 provided at the front portion of the vehicle 78. It is supplied to the electronic control unit 74.

  The inter-vehicle distance determination unit 76 determines whether the inter-vehicle distance D detected by the front radar 80 is equal to or less than a predetermined inter-vehicle distance determination value Dα, and the inter-vehicle distance D detected by the front radar 80 is preset. It is determined whether or not the inter-vehicle distance determination value Dβ is greater. That is, the inter-vehicle distance determination unit 76 determines whether the inter-vehicle distance D detected by the front radar 80 is a preset range, for example, Dα <D, or a preset range, for example, Dβ ≦ D ≦ Dα. Alternatively, it is determined whether or not a preset range D <Dβ.

The inter-vehicle distance determination value Dα is a lower limit value of the inter-vehicle distance D set in advance by, for example, an experiment for performing the cylinder resting inertial traveling, and the inter-vehicle distance determination value Dβ performs the engine brake traveling. For example, it is a lower limit value of the inter-vehicle distance D set in advance by experiments or the like, and the inter-vehicle distance determination value Dα is set larger than the inter-vehicle distance determination value Dβ. The inter-vehicle distance determination values Dα and Dβ, which are the lower limit values of the preset inter-vehicle distance D, are the upper limit value of the magnitude of deceleration by the engine brake required during traveling, that is, the upper limit value of the necessity of the engine brake. For example, as the inter-vehicle distance determination values Dα and Dβ decrease, the upper limit value of the magnitude of deceleration by the engine brake required during traveling, that is, the upper limit value of the necessity of the engine brake is increased. It is getting bigger. Further, the inter-vehicle distance determination value (upper limit value) D _MIN of the inter-vehicle distance D at which the engine brake traveling is performed is smaller than the inter-vehicle distance determination value Bβ, for example, zero.

  Further, in the present embodiment, the inter-vehicle distance D predicts the magnitude of deceleration caused by the engine brake required by the driver during traveling, that is, indicates the necessity of the engine brake, and the inter-vehicle distance D is As the distance becomes smaller, the possibility of the driver's brake input for adjusting the inter-vehicle distance D increases, and the deceleration by the engine brake required by the driver increases, and the necessity of the engine brake increases. The inter-vehicle distance determination values Dα and Dβ are determination values for determining the degree of necessity of the engine brake. If the inter-vehicle distance D is larger than the inter-vehicle distance determination value Dα, the driver is required when traveling. The magnitude of deceleration due to engine braking is relatively small, and the need for engine braking is relatively small. If the inter-vehicle distance D is equal to or less than the inter-vehicle distance determination value Dα and is equal to or greater than the inter-vehicle distance determination value Dβ, the magnitude of deceleration by the engine brake required by the driver during traveling is relatively large, and the necessity of the engine brake is present. It becomes relatively large. If the inter-vehicle distance D is smaller than the inter-vehicle distance determination value Dβ, the magnitude of deceleration of the engine brake required by the driver during traveling is such that the inter-vehicle distance D is less than the inter-vehicle distance determination value Dα and greater than the inter-vehicle distance determination value Dβ. The need for the engine brake is even greater than that of the engine. That is, the inter-vehicle distance determination unit 76 is a means for determining the magnitude of necessity of the engine brake while the vehicle is traveling.

  The inertial travel switching control unit 62 determines that the accelerator pedal 68 is in the OFF state by the inertial travel desire determination unit 58, and if the inter-vehicle distance determination unit 76 determines that the inter-vehicle distance D is greater than the inter-vehicle distance determination value Dα, that is, the inter-vehicle distance. When it is determined that D is within the range of Dα <D, the neutral inertia traveling unit 56 performs neutral inertia traveling.

  Further, the inertial travel switching control unit 62 determines that the accelerator pedal 68 is in the OFF state by the inertial travel desire determination unit 58, and the inter-vehicle distance determination unit 76 determines that the inter-vehicle distance D is equal to or greater than the inter-vehicle distance determination value Dβ. When it is determined that the distance D is equal to or less than the amount determination value Bα, that is, the inter-vehicle distance D is determined to be within the range of Dβ ≦ D ≦ Dα, the cylinder deactivation inertia traveling unit 54 performs the cylinder deactivation inertia traveling.

  Further, the inertial travel switching control unit 62 determines that the accelerator pedal 68 is in the OFF state by the inertial travel desire determination unit 58 and the inter-vehicle distance determination unit 76 determines that the inter-vehicle distance D is smaller than the inter-vehicle distance determination value Dβ. When it is determined that the inter-vehicle distance D is within the range of D <Dβ, the normal traveling unit 52 performs engine brake traveling.

  FIG. 14 shows an essential part of the control operation of the electronic control unit 74, that is, the inertia traveling switching control unit 62 determines whether the neutral inertia traveling, the cylinder deactivation inertia traveling, or the engine brake traveling is performed by the inter-vehicle distance determining unit 76. It is a flowchart explaining the control action which performs based on determination and implements one of those driving | running | working. FIG. 15 is a time chart corresponding to the main part of the control operation of the electronic control unit 74 of FIG.

  In FIG. 14, in S11 corresponding to the inertial travel desire determination unit 58, it is determined whether or not the accelerator pedal 68 is in an OFF state in the relatively high speed steady travel state. If the determination of S11 is negative, S11 is repeatedly executed. For example, when the depression of the accelerator pedal 68 is turned off as shown at time t1 in FIG. 15, the determination of S11 is affirmed. S12 corresponding to the inter-vehicle distance determination unit 76 is executed.

  In S12, it is determined whether or not the inter-vehicle distance D with the preceding vehicle 82 is equal to or less than the inter-vehicle distance determination value Dα, that is, whether or not the necessity of the engine brake is relatively large and the braking performance is important. If it is determined in S12 that the inter-vehicle distance D is greater than the inter-vehicle distance determination value Dα, for example, as shown between t2 and t3 in FIG. 15, that is, the determination of S12 is negative. Then, in S13 corresponding to the inertial traveling switching control unit 62 and the neutral inertial traveling unit 56, the N-range coasting control is performed and the neutral inertial traveling is performed.

  Further, during the neutral inertia traveling, for example, when the inter-vehicle distance D becomes equal to or less than the inter-vehicle distance determination value Dα as shown between t3 and t4 in FIG. 15, it is determined in S12 that the braking performance is important. That is, the determination in S12 is affirmed and S14 corresponding to the inter-vehicle distance determination unit 76 is executed. In S14, it is determined whether or not the inter-vehicle distance D is smaller than the inter-vehicle distance determination value Dβ, that is, whether or not the necessity of the engine brake is larger than that in S12 and the brake performance is more important than that in S12. Is done. Then, if it is determined in S14 that the inter-vehicle distance D is equal to or greater than the inter-vehicle distance determination value Bβ as shown in the period from t3 to t4 in FIG. If the determination is negative, the valve stop free-run control is performed in S15 corresponding to the inertia traveling switching control unit 62 and the cylinder deactivation inertia traveling unit 54, and the cylinder deactivation inertia traveling is performed.

  Further, during the cylinder resting inertia traveling, for example, as shown after t4 in FIG. 15, when the inter-vehicle distance D becomes smaller than the inter-vehicle distance determination value Bβ, it is determined in S14 that the above-described brake performance is more important. If the determination in S14 is affirmative, fuel cut control is performed in S16 corresponding to the inertial travel switching control unit 62 and the normal travel unit 52, and engine brake travel is performed.

  As described above, according to the electronic control unit 74 provided in the vehicle drive device 10 of the present embodiment, the inter-vehicle distance determination unit 76 determines the necessity of the engine brake according to the inter-vehicle distance D with the preceding vehicle 82. to decide. For this reason, the necessity of the engine brake at the time of traveling can be suitably predicted from the inter-vehicle distance D.

  As shown in FIG. 16, the electronic control device (travel control device) 84 of the vehicle drive device 10 of the present embodiment is provided with a brake provided with the electronic control device 50 as compared with the electronic control device 50 of the first embodiment described above. The difference is that the stepping amount determination unit 60 is replaced by a downward gradient determination unit 86, and the rest is substantially the same as the electronic control device 50 of the first embodiment. Further, the electronic control device 84 is supplied with a signal representing a downward gradient (gradient) Φ (angle) of the road surface R from, for example, a road surface gradient sensor 88 that detects longitudinal acceleration. The downward slope Φ of the road surface R has a positive value as shown in FIG. 17 in the downward slope and a negative value in the upward slope.

  The downward gradient determination unit 86 determines whether the downward gradient Φ detected by the road surface gradient sensor 88 is greater than a predetermined gradient determination value α and the downward gradient Φ detected by the road surface gradient sensor 88 is preset. It is determined whether or not the gradient determination value β is larger. In other words, the downward gradient determination unit 86 determines whether the downward gradient Φ detected by the road surface gradient sensor 88 is a preset range 0 <Φ ≦ α or a preset range α <Φ ≦ β. Alternatively, it is determined whether or not a preset range β <Φ.

Note that the gradient determination value α is an upper limit value of the downward gradient Φ set in advance by, for example, an experiment that performs the cylinder resting inertia traveling, and the gradient determination value β is, for example, an experiment that performs the engine brake traveling. The gradient determination value β is set higher than the gradient determination value α and the gradient determination values α and β are set larger than 0 (0 <α <β). Note that the gradient determination values α and β, which are the upper limit values of the preset downward gradient Φ, are upper limit values of the magnitude of deceleration by the engine brake required during traveling, that is, upper limit values of the necessity of the engine brake. For example, as the gradient determination values α and β increase, the upper limit value of the magnitude of deceleration by the engine brake required during traveling, that is, the upper limit value of the necessity of the engine brake is increased. It is getting bigger. In addition, the gradient determination value (upper limit value) Φ _MAX of the downward gradient Φ for carrying out the engine brake traveling is a value larger than a predetermined gradient determination value β.

  In the present embodiment, the downward gradient Φ predicts the magnitude of deceleration caused by the engine brake required by the driver during traveling, that is, indicates the necessity of the engine brake. As the speed increases, the speed increases due to coasting and the possibility of the driver's brake input increases, and the deceleration by the engine brake required by the driver increases, and the need for the engine brake increases. Becomes larger. The gradient determination values α and β are determination values for determining the degree of necessity of the engine brake. If the downward gradient Φ is equal to or less than the gradient determination value α, the engine requested by the driver during traveling is used. The magnitude of deceleration due to braking is relatively small, and the need for the engine brake is relatively small. If the downward gradient Φ is greater than the gradient determination value α and equal to or less than the gradient determination value β, the amount of deceleration by the engine brake required by the driver during traveling is relatively large and the necessity of the engine brake is relatively high. Become. If the downhill slope Φ is greater than the slope judgment value β, the deceleration of the engine brake required by the driver during driving is compared with that in which the downhill slope Φ is greater than the slope judgment value α and less than the slope judgment value β. The need for the engine brake is further increased. That is, the descending slope determination unit 86 is a means for determining the necessity of the engine brake while the vehicle is traveling.

  The inertial travel switching control unit 62 determines that the accelerator pedal 68 is in the OFF state by the inertial travel desire determination unit 58 and the downward gradient Φ is equal to or less than the gradient determination value α, that is, the downward gradient Φ is 0. If it is determined that <Φ ≦ α, the neutral inertia traveling unit 56 performs neutral inertia traveling.

  In addition, the inertial travel switching control unit 62 determines that the accelerator pedal 68 is in the OFF state by the inertial travel desire determination unit 58 and the downward gradient Φ is greater than the gradient determination value α by the downward gradient determination unit 86. If it is determined that β is equal to or less than β, that is, the downward gradient Φ is within the range of α <Φ ≦ β, the cylinder deactivation inertia traveling unit 54 performs the cylinder deactivation inertia traveling.

  In addition, the inertial travel switching control unit 62 determines that the accelerator pedal 68 is in the OFF state by the inertial travel desire determination unit 58, and the downward gradient Φ is greater than the gradient determination value β by the downward gradient determination unit 86, that is, the downward gradient. If it is determined that Φ is within a range of β <Φ, the normal traveling unit 52 performs engine brake traveling.

  FIG. 18 is a diagram showing a main part of the control operation of the electronic control unit 84, that is, the inertial traveling switching control unit 62 that determines whether the neutral inertial traveling, the cylinder resting inertial traveling, or the engine brake traveling is performed. It is a flowchart explaining the control action which performs based on determination and implements one of those driving | running | working. FIG. 19 is a time chart corresponding to the main part of the control operation of the electronic control unit 84 of FIG.

  In FIG. 18, in S21 corresponding to the inertial travel desire determination unit 58, it is determined whether or not the accelerator pedal 68 is in an OFF state in the relatively high speed steady travel state. If the determination of S21 is negative, S21 is repeatedly executed. However, for example, when the depression of the accelerator pedal 68 is turned off as shown at time t1 in FIG. 19, the determination of S21 is affirmed. S22 corresponding to the downward gradient determination unit 86 is executed.

  In S22, it is determined whether or not the downward gradient Φ is larger than the gradient determination value α, that is, whether or not the necessity of the engine brake is relatively large and the brake performance is important. Then, in S22, for example, when it is determined that the downward gradient Φ is greater than the gradient determination value α and the brake performance is important as shown in the period from t2 to t3 in FIG. 11, that is, the determination in S22 is affirmed. S23 corresponding to the descending slope determination unit 86 is executed. In S23, it is determined whether or not the downward gradient Φ is larger than the gradient determination value β, that is, whether or not the necessity of the engine brake is larger than that in S22 and the brake performance is more important than that in S22. The Then, when it is determined in S23 that the downward gradient Φ is equal to or less than the gradient determination value β as shown in the period from t2 to t3 in FIG. If NO is determined, the valve stop free-run control is performed in S24 corresponding to the inertia traveling switching control unit 62 and the cylinder deactivation inertia traveling unit 54, and the cylinder deactivation inertia traveling is performed.

  Further, during the cylinder resting inertia running, for example, as shown between t3 and t4 in FIG. 19, when the downward gradient Φ is equal to or smaller than the gradient determination value α, it is determined in S22 that the brake performance is not an important scene. The determination of S22 is denied, and N range coasting control is performed and neutral coasting is performed in S25 corresponding to coasting switching control unit 62 and neutral coasting traveling unit 56.

  Further, during the neutral inertia traveling, for example, when the downward gradient Φ becomes larger than the gradient determination value α as shown between t4 and t5 in FIG. 19, the determination of S22 is affirmed and the determination of S23 is performed as described above. In the negative, the cylinder deactivation inertia traveling is performed in S24.

  Further, during the cylinder resting inertia running, for example, as shown after t5 in FIG. 19, when the downward gradient Φ becomes larger than the gradient determination value β, it is determined in S23 that the above-described brake performance is emphasized, that is, S23. Is affirmed, the fuel cut control is performed in S26 corresponding to the inertial travel switching control unit 62 and the normal travel unit 52, and the engine brake travel is performed.

  As described above, according to the electronic control device 84 provided in the vehicle drive device 10 of the present embodiment, the downward gradient determination unit 86 determines the necessity of the engine brake based on the downward gradient Φ of the road surface R. . For this reason, the necessity of the engine brake at the time of traveling can be suitably predicted by the downward gradient Φ of the road surface R.

  As mentioned above, although the Example of this invention was described in detail based on drawing, this invention is applied also in another aspect.

  In this embodiment, the neutral inertia traveling is an inertia traveling in which the engine 12 and the drive wheels 20 are operated by supplying fuel to the engine 12 in a state where the power transmission path between the engine 12 and the drive wheels 20 is disconnected by the clutch C1. 12 may be inertial running in which the fuel supply to 12 is stopped (fuel cut F / C) to stop the rotation. In the neutral inertia running, when the fuel supply to the engine 12 is stopped and the rotation is stopped, the fuel efficiency of the vehicle is preferably improved.

  In the first embodiment, the necessity of the engine brake is determined by the magnitude of the brake depression amount B of the brake pedal 68 as means for determining the necessity of the engine brake. The necessity of the engine brake may be determined based on the master cylinder pressure of the master cylinder 44. Further, for example, the necessity of the engine brake may be determined from ON / OFF information of a switch (two or more stages) linked with the movement of the brake pedal 68.

  In the second embodiment, the necessity of the engine brake is determined based on the current distance D between the vehicles detected by the front radar 80 as a means for determining the necessity of the engine brake. A future inter-vehicle distance may be estimated from the acceleration difference between the vehicle 82 and the vehicle (own vehicle) 78, and the necessity of the engine brake may be determined based on the estimated future inter-vehicle distance.

  In the third embodiment, the downward gradient Φ is obtained from a road surface gradient sensor 88 such as a G sensor that detects longitudinal acceleration. However, the information acquisition means for the downward gradient Φ is not limited to the road surface gradient sensor 88. For example, the map information stored in advance based on the actual driving force or throttle valve opening and vehicle speed of the engine 12 from the relationship between the driving force or throttle valve opening and the vehicle speed of the engine 12 on a flat road stored in advance. For example, the downward gradient Φ may be obtained based on the actual point.

Further, in this embodiment, the upper limit value of the necessity of the engine brake for executing the engine brake traveling, that is, the depression amount determination value B _MAX , the inter-vehicle distance determination value D _MIN , and the gradient determination value Φ _MAX are set. Since the amount determination values Bα and Bβ, the inter-vehicle distance determination values Dα and Dβ, and the gradient determination values α and β can be temporarily controlled, the stepping amount determination value B _MAX , the inter-vehicle distance determination value D _MIN , and the gradient determination value are not necessarily limited. There is no need to set Φ _MAX .

  Further, in the present embodiment, the depression amount determination values Bα and Bβ, the inter-vehicle distance determination values Dα and Dβ, and the gradient determination values α and β are predetermined constant values, but the depression amount determination values Bα, Bβ, inter-vehicle distance determination values Dα and Dβ, and gradient determination values α and β may be functions of the μ state of the road surface R, for example, and the determination values may be variably set in consideration of them. These variable settings may be such that the stepping amount determination values Bα and Bβ, the inter-vehicle distance determination values Dα and Dβ, and the gradient determination values α and β are changed continuously, or may be changed step by step including two steps. It is often determined in advance by a data map, an arithmetic expression, or the like.

  In the present embodiment, for example, in the brake depression amount determination unit 60 of the first embodiment, the neutral inertia traveling is performed when the brake depression amount B is 0 <B ≦ Bα, and the cylinder when the brake depression amount B is Bα <B ≦ Bβ. The engine braking traveling was performed when the resting inertia traveling was performed and the depression amount B was Bβ <B. However, when the brake depression amount B is 0 <B ≦ Bα, the neutral inertia traveling is necessarily performed, and when the brake depression amount B is Bα <B ≦ Bβ, the cylinder deactivation inertia traveling is necessarily performed, and the brake depression amount B is Bβ < At the time of B, the engine brake traveling is not necessarily performed. In other words, according to the present invention, when the brake depression amount B is 0 <B ≦ Bα, the neutral inertia traveling is changed to the side where the neutral inertia traveling is easily performed. Those that change to the easy side, and those that change to the side where the engine brake travel is easily performed when the brake depression amount B is Bβ <B are included. The same applies to the inter-vehicle distance determination unit 76 and the downward gradient determination unit 86.

  The above description is only an embodiment, and the present invention can be implemented in variously modified and improved forms based on the knowledge of those skilled in the art.

12: Engine 20: Drive wheels 50, 74, 84: Electronic control device (travel control device)
52: Normal traveling section 54: Cylinder deactivation inertia traveling section 56: Neutral inertia traveling section 62: Inertia traveling switching control section 60: Brake depression amount determination section 68: Brake pedal 76: Inter-vehicle distance determination section 82: Front vehicle 86: Down slope Judgment part B: Brake depression amount Bα, Bβ, B _MAX : Depression amount determination value (upper limit value)
C1: Clutch (clutch device)
D: Distance between vehicles (distance)
Dα, Dβ, _DMIN : Inter-vehicle distance judgment value (upper limit value)
R: Road surface Φ: Down slope (gradient)
α, β, Φ _MAX : Gradient judgment value (upper limit)

Claims (6)

An engine having a plurality of cylinders, a clutch device that separates the engine and the drive wheels, and a means for determining the necessity of engine braking, and normal running that travels by connecting the engine and the drive wheels; A traveling control device for a vehicle that performs neutral inertia traveling by separating the engine and the drive wheel,
The vehicle further includes cylinder deactivation inertia traveling in which the engine and the driving wheel are coupled to each other while at least some of the cylinders of the engine are deactivated.
The deceleration due to the engine brake of the running vehicle has a characteristic that increases in the order of the neutral coasting, the cylinder deactivation coasting, and the normal traveling.
A vehicle travel control device selected when the necessity of the engine brake increases in the order of the neutral coasting, the cylinder deactivation coasting, and the normal traveling.   2. The vehicle travel control apparatus according to claim 1, wherein the means for determining the necessity for the engine brake determines the necessity for the engine brake based on any one of a depression of a brake pedal, a road surface gradient, and a distance from a preceding vehicle. The necessity of the engine brake is the magnitude of deceleration required during traveling,
When the required deceleration is determined by depressing the brake pedal in the means for determining the necessity of the engine brake, the request is determined by the engine brake of the vehicle and the foot brake by depressing the brake pedal. The braking force is issued so that the deceleration is reduced,
The vehicle travel control apparatus according to claim 2, wherein a braking force generated by the foot brake is larger than a braking force generated by the engine brake. The upper limit value of the necessity of the engine brake for performing the cylinder resting inertia traveling is set to be larger than the upper limit value of the engine brake for performing the neutral inertia traveling,
The upper limit value of the necessity of the engine brake for performing the normal traveling is set larger than the upper limit value of the necessity of the engine brake for performing the cylinder deactivation inertia traveling. The vehicle travel control device according to claim 1. During the neutral inertia traveling, when the necessity of the engine brake becomes larger than the upper limit value of the necessity of the engine brake for performing the neutral inertia traveling, the neutral inertia traveling is terminated and the cylinder resting inertia traveling is performed. ,
During the cylinder deactivation inertia traveling, when the necessity of the engine brake becomes larger than the upper limit value of the engine brake necessity for performing the cylinder deactivation inertia traveling, the cylinder deactivation inertia traveling is terminated and the normal traveling is performed. The vehicle travel control apparatus according to claim 4.   The neutral inertia traveling is an inertia traveling in which the fuel supply to the engine is stopped by stopping the fuel supply to the engine with the engine and the driving wheel being separated or an inertia traveling in which the fuel is supplied to the engine to operate. The vehicle travel control apparatus according to claim 1, wherein the vehicle travel control apparatus is a vehicle travel control apparatus.

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