JP2012056390A - Engine driving device - Google Patents

Abstract

An object of the present invention is to suppress deterioration of fuel consumption without increasing a sense of incongruity given to a driver when the output shaft speed of an engine is increased in order to prevent gear rattling noise.
When the torque of a motor generator as a drive source decreases, the engine speed is increased from the speed determined by the first operating line to the speed determined by the second operating line. The first operating line is farther away from the second operating line as either the vehicle speed or the engine speed is higher.
[Selection] Figure 7

Description

  The present invention relates to an engine drive device, and more particularly to a technique for driving an engine mounted on a vehicle provided with an electric motor as a drive source.

  Hybrid vehicles equipped with an engine and an electric motor as drive sources are known. In such a hybrid vehicle, it is possible to assist the engine with an electric motor or to travel using only the electric motor as a drive source. The engine and the electric motor are connected through, for example, a planetary gear set. As an example, the output shaft of the engine is connected to the planetary carrier, and the output shaft of the electric motor is connected to the ring gear. A generator is connected to the sun gear.

  When the engine and the electric motor are connected using the planetary gear set, for example, when the output torque of the electric motor is zero, a gap may be generated between the gears connecting the engine and the electric motor. If the engine output torque fluctuates with a gap between the gears, the gear teeth may collide with each other to generate sound. In order to suppress the generation of such sound, Japanese Patent Application Laid-Open No. 11-93725 (Patent Document 1) discloses an internal combustion engine as a power source and an internal combustion engine having at least three axes and one of the three axes. In a power output device including an output shaft including a gear mechanism in which a drive shaft is coupled to another shaft and an electric motor coupled to the remaining shaft of the gear mechanism, rattling noise is generated between the gears of the gear mechanism. A power output device that controls the number of revolutions of an internal combustion engine to a predetermined value or more when a condition is detected is disclosed.

JP 11-93725 A

  However, if the engine output shaft rotational speed is automatically increased by using the power output device described in Japanese Patent Application Laid-Open No. 11-93725, the engine driving noise increases even when the driver is not operating. To do. As a result, the driver may feel uncomfortable. In order to suppress the increase amount of the driving sound, the output shaft rotational speed when the gear rattling sound can be generated is reduced by maintaining the engine output shaft rotational speed relatively high. It is possible to do. However, in this case, the engine is operated far away from the driving state where the fuel efficiency is optimal. As a result, fuel consumption can deteriorate.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to suppress deterioration in fuel consumption without increasing the sense of discomfort given to the driver.

  An engine driving device mounted on a vehicle provided with an electric motor as a driving source includes a driving means for driving the engine at a first output shaft rotational speed in a state where the electric motor outputs torque, And an increase means for increasing the output shaft rotational speed of the engine from the first output shaft rotational speed to the second output shaft rotational speed when the motor torque decreases. The first output shaft rotational speed is more greatly separated from the second output shaft rotational speed as either the vehicle speed or the output shaft rotational speed is higher.

  According to this configuration, in a state where the vehicle speed or the output shaft rotational speed is high, that is, in a state where the noise accompanying the traveling of the vehicle is large, the increase amount of the engine output shaft rotational speed is increased. Thereby, the output shaft rotation speed before being increased can be made as low as possible. Therefore, it can contribute to the improvement of fuel consumption. Further, in a state where the noise accompanying the traveling of the vehicle is large, even if the amount of increase in the driving sound of the engine 100 is large, it is difficult for the driver to feel uncomfortable. As a result, deterioration of fuel consumption can be suppressed without increasing the uncomfortable feeling given to the driver.

  In another engine drive device, the increase means increases the output shaft speed faster as either the vehicle speed or the output shaft speed is higher.

  According to this configuration, the increase speed of the output shaft rotational speed of the engine is increased in a state where the noise accompanying the traveling of the vehicle is large. As a result, the output shaft rotational speed of the engine can be quickly increased before the sound is generated in, for example, a gear or the like with a decrease in the output torque of the electric motor. Therefore, the generation of sound can be more effectively suppressed. Further, in a state where the noise accompanying the traveling of the vehicle is large, even if the driving sound of the engine increases rapidly, it is difficult for the driver to feel uncomfortable. As a result, it is possible to effectively suppress the generation of noise associated with a decrease in the output torque of the electric motor without increasing the sense of discomfort given to the driver.

  In another engine drive device, the increasing means increases the engine output shaft rotational speed from the first output shaft rotational speed to the second output shaft rotational speed while maintaining the output power of the engine.

  According to this configuration, by maintaining the output power of the engine, it is possible to increase the output shaft rotation speed while suppressing fluctuations in the behavior of the vehicle.

  In another engine drive device, the output power of the engine is determined according to the operation of the driver. The first output shaft rotational speed is a rotational speed that realizes an output power determined in accordance with a driver's operation on a first predetermined line indicating the relationship between the engine output shaft rotational speed and the output torque. It is. The second output shaft rotational speed indicates the relationship between the engine output shaft rotational speed and the output torque. On the second line where the output shaft rotational speed at the same output power is higher than that of the first line, This is the number of revolutions that realizes the output power determined according to the operation of the driver.

  According to this configuration, the output shaft rotational speed and output torque of the engine can be changed in a desired manner.

  In another engine drive device, the first line is more separated from the second line as either the vehicle speed or the output shaft speed is higher.

  According to this configuration, when the first line is further away from the second line as one of the vehicle speed and the output shaft rotational speed is higher, the noise associated with the traveling of the vehicle is larger. The amount of increase in the engine output shaft speed can be increased.

  Another engine drive device is an engine drive device mounted on a vehicle provided with an electric motor as a drive source. In the state where the electric motor outputs torque, the driving device is configured to drive the engine in accordance with a first operating line that defines an operating point of the engine, and the first operation when the torque of the electric motor decreases. Means for driving the engine according to a second operating line that defines the operating point of the engine, which is further from the optimal fuel consumption line than the line. The first driving line is closer to the optimum fuel consumption line as one of the vehicle speed and the output shaft speed is higher.

  According to this configuration, the engine can be driven at an operating point closer to the optimum fuel consumption line in a state where the vehicle speed or the output shaft rotational speed is high, that is, in a state where the noise accompanying the traveling of the vehicle is large. Therefore, it can contribute to the improvement of fuel consumption. Further, in a state where the noise accompanying the traveling of the vehicle is large, even if the driving sound of the engine 100 increases greatly due to the driving point moving from the first driving line to the second driving line, It is difficult to give a sense of incongruity. As a result, deterioration of fuel consumption can be suppressed without increasing the uncomfortable feeling given to the driver.

It is a schematic block diagram which shows the power train of a hybrid vehicle. It is a schematic block diagram which shows an engine. It is an alignment chart of a power split mechanism. It is an alignment chart of a transmission. It is a figure which shows the driving | running state of an engine. It is a figure which shows the 1st operating line and 2nd operating line which defined engine speed and output torque. It is a figure which shows the 1st driving line which is largely separated from the 2nd driving line, so that vehicle speed is high. It is a figure which shows the 1st driving line which is spaced apart from the 2nd driving line so that an engine speed is high. It is a flowchart which shows the process which ECU performs.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

  A power train of a hybrid vehicle equipped with the drive device according to the present embodiment will be described with reference to FIG. Note that the control device according to the present embodiment is realized, for example, when ECU 1000 executes a program recorded in ROM (Read Only Memory) 1002 of ECU (Electronic Control Unit) 1000.

  As shown in FIG. 1, the power train includes an engine 100, a first motor generator (MG1) 200, a power split mechanism 300 that synthesizes or distributes torque between the engine 100 and the first motor generator 200, The second motor generator (MG2) 400 and the transmission 500 are mainly configured.

  The engine 100 is a known power unit that burns fuel and outputs motive power, and is configured to be able to electrically control operating conditions such as throttle opening (intake amount), fuel supply amount, and ignition timing. Yes. The control is performed, for example, by the ECU 1000 mainly including a microcomputer.

  Referring to FIG. 2, engine 100 draws air from air cleaner 102. The intake air amount is adjusted by the throttle valve 104. The throttle valve 104 is an electronic throttle valve that is driven by a motor.

  Air is mixed with fuel in the cylinder 106 (combustion chamber). Fuel is directly injected into the cylinder 106 from the injector 108. That is, the injection hole of the injector 108 is provided in the cylinder 106. The fuel is injected from the intake side (the side where air is introduced) of the cylinder 106.

  Fuel is injected during the intake stroke. Note that the timing of fuel injection is not limited to the intake stroke. In this embodiment, the engine 100 is described as a direct injection engine in which the injection hole of the injector 108 is provided in the cylinder 106. However, in addition to the direct injection injector 108, a port injection injector is provided. May be. Further, only a port injection injector may be provided.

  The air-fuel mixture in the cylinder 106 is ignited by the spark plug 110 and burns. The air-fuel mixture after combustion, that is, the exhaust gas is purified by the three-way catalyst 112 and then discharged outside the vehicle. The piston 114 is pushed down by the combustion of the air-fuel mixture, and the crankshaft 116 rotates.

  An intake valve 118 and an exhaust valve 120 are provided at the top of the cylinder 106. The amount and timing of air introduced into the cylinder 106 is controlled by the intake valve 118. The amount and timing of the exhaust gas discharged from the cylinder 106 is controlled by the exhaust valve 120. The intake valve 118 is driven by a cam 122. The exhaust valve 120 is driven by a cam 124.

  The intake valve 118 is changed in opening / closing timing (phase) by a VVT (Variable Valve Timing) mechanism 126. The opening / closing timing of the exhaust valve 120 may be changed.

  In the present embodiment, the camshaft (not shown) provided with the cam 122 is rotated by the VVT mechanism 126, whereby the opening / closing timing of the intake valve 118 is controlled. The method for controlling the opening / closing timing is not limited to this. In the present embodiment, VVT mechanism 126 is operated by hydraulic pressure.

  Engine 100 is controlled by ECU 1000. ECU 1000 controls the throttle opening, the ignition timing, the fuel injection timing, the fuel injection amount, and the opening / closing timing of intake valve 118 so that engine 100 is in a desired operating state. ECU 1000 receives signals from cam angle sensor 800, crank angle sensor 802, water temperature sensor 804, and air flow meter 806.

  The cam angle sensor 800 outputs a signal representing the cam position. The crank angle sensor 802 outputs a signal representing the rotational speed (engine rotational speed) NE of the crankshaft 116 and the rotational angle of the crankshaft 116. Water temperature sensor 804 outputs a signal representing the temperature of cooling water of engine 100 (hereinafter also referred to as water temperature). Air flow meter 806 outputs a signal representing the amount of air KL taken into engine 100.

  ECU 1000 controls engine 100 based on signals input from these sensors, a map stored in ROM 1002, and a program.

  Returning to FIG. 1, the first motor generator 200 is a three-phase AC rotating electric machine as an example, and is configured to generate a function as an electric motor (motor) and a function as a generator (generator). It is connected to a power storage device 700 such as a battery via an inverter 210. By controlling the inverter 210, the output torque or regenerative torque of the first motor generator 200 is appropriately set. The control is performed by the ECU 1000. The stator (not shown) of the first motor generator 200 is fixed and does not rotate.

  The power split mechanism 300 includes a sun gear (S) 310 that is an external gear, a ring gear (R) 320 that is an internal gear arranged concentrically with the sun gear (S) 310, and the sun gear (S). This is a known gear mechanism that generates a differential action by using a carrier (C) 330 that rotates and revolves a pinion gear meshing with 310 and a ring gear (R) 320 as three rotating elements. The output shaft of the engine 100 is connected to a carrier (C) 330 as a first rotating element via a damper. In other words, the carrier (C) 330 is an input element.

  On the other hand, the rotor (not shown) of the 1st motor generator 200 is connected with the sun gear (S) 310 which is a 2nd rotation element. Therefore, the sun gear (S) 310 is a so-called reaction force element, and the ring gear (R) 320 that is the third rotation element is an output element. The ring gear (R) 320 is connected to an output shaft 600 connected to drive wheels (not shown). The rotational speed of the output shaft 600 is detected by the output shaft rotational speed sensor 602, and a signal representing the output shaft rotational speed is input to the ECU 1000.

  FIG. 3 shows an alignment chart of the power split mechanism 300. As shown in FIG. 3, when the reaction torque generated by the first motor generator 200 is input to the sun gear (S) 310 with respect to the torque output from the engine 100 input to the carrier (C) 330, these torques are added or subtracted. The torque having the magnitude appears in the ring gear (R) 320 serving as an output element. In that case, the rotor of the first motor generator 200 is rotated by the torque, and the first motor generator 200 functions as a generator. In addition, when the rotation speed (output rotation speed) of ring gear (R) 320 is constant, the rotation speed of engine 100 is continuously (steplessly) changed by changing the rotation speed of first motor generator 200. ) Can be changed. That is, control for setting the rotation speed of engine 100 to, for example, the rotation speed with the best fuel efficiency can be performed by controlling first motor generator 200. The control is performed by the ECU 1000.

  If the engine 100 is stopped during traveling, the first motor generator 200 is rotating in the reverse direction. From this state, when the first motor generator 200 is caused to function as an electric motor and torque is output in the forward rotation direction, the carrier ( C) Torque in the direction of rotating the engine 100 connected to 330 acts in the forward direction, and the first motor generator 200 can start the engine 100 (motoring or cranking). In that case, torque in a direction to stop the rotation acts on the output shaft 600. Therefore, the driving torque for traveling can be maintained by controlling the torque output from the second motor generator 400, and at the same time, the engine 100 can be started smoothly. This type of hybrid type is called a mechanical distribution type or a split type.

  Returning to FIG. 1, second motor generator 400 is a three-phase AC rotating electric machine as an example, and is configured to generate a function as an electric motor and a function as a generator. A power storage device 700 such as a battery is connected via an inverter 310. By controlling the inverter 310, the power running and regeneration and the torque in each case are controlled. The stator (not shown) of second motor generator 400 is fixed and does not rotate.

  The transmission 500 is configured by a set of Ravigneaux planetary gear mechanisms. A first sun gear (S1) 510 and a second sun gear (S2) 520, which are external gears, are provided, and the first pinion 531 meshes with the first sun gear (S1) 510, and the first The pinion 531 meshes with the second pinion 532, and the second pinion 532 meshes with the ring gear (R) 540 arranged concentrically with the sun gears 510 and 520.

  Each pinion 531 and 532 is held by a carrier (C) 550 so as to rotate and revolve freely. Further, the second sun gear (S 2) 520 is meshed with the second pinion 532. Therefore, the first sun gear (S1) 510 and the ring gear (R) 540 form a mechanism corresponding to the double pinion type planetary gear mechanism together with the pinions 531 and 532, and the second sun gear (S2) 520 and the ring gear (R). 540 and the second pinion 532 constitute a mechanism corresponding to a single pinion planetary gear mechanism.

  Further, the transmission 500 is provided with a B1 brake 561 that selectively fixes the first sun gear (S1) 510 and a B2 brake 562 that selectively fixes the ring gear (R) 540. These brakes 561 and 562 are so-called friction engagement elements that generate an engagement force by a friction force, and a multi-plate type engagement device or a band type engagement device can be adopted. And these brakes 561 and 562 are comprised so that the torque capacity may change continuously according to the engaging force by oil_pressure | hydraulic. Further, the second motor generator 400 described above is connected to the second sun gear (S2) 520. Carrier (C) 550 is connected to output shaft 600.

  Therefore, in the above-described transmission 500, the second sun gear (S2) 520 is a so-called input element, and the carrier (C) 550 is an output element. By engaging the B1 brake 561, the transmission ratio is “ A high speed stage greater than 1 ″ is set. By engaging the B2 brake 562 instead of the B1 brake 561, a low speed stage having a higher gear ratio than the high speed stage is set.

  The speed change between the respective speeds is executed based on a traveling state such as a vehicle speed and a required driving force (or accelerator opening). More specifically, the shift speed region is determined in advance as a map (shift diagram), and control is performed so as to set one of the shift speeds according to the detected driving state.

  FIG. 4 shows an alignment chart of the transmission 500. As shown in FIG. 4, if ring gear (R) 540 is fixed by B2 brake 562, low speed stage L is set, and torque output from second motor generator 400 is amplified in accordance with the gear ratio and applied to output shaft 600. Added. On the other hand, if the first sun gear (S1) 510 is fixed by the B1 brake 561, the high speed stage H having a smaller gear ratio than the low speed stage L is set. Since the gear ratio at the high speed stage H is also larger than “1”, the torque output from the second motor generator 400 is increased according to the gear ratio and added to the output shaft 600.

  It should be noted that, in a state where the respective gear stages L and H are constantly set, the torque applied to the output shaft 600 is a torque obtained by increasing the output torque of the second motor generator 400 according to the gear ratio. In the shift transition state, the torque is affected by the torque capacity at each brake 561 and 562, the inertia torque accompanying the change in the rotational speed, and the like. The torque applied to the output shaft 600 is positive torque when the second motor generator 400 is driven, and is negative torque when the second motor generator 400 is driven.

  As shown in FIG. 5, when the traveling power of the hybrid vehicle is smaller than the engine start threshold, the hybrid vehicle travels using only the driving force of second motor generator 400.

  On the other hand, when the traveling power of the hybrid vehicle exceeds the engine start threshold value, engine 100 is driven. Thus, the hybrid vehicle travels using the driving force of engine 100 in addition to or instead of the driving force of second motor generator 400. Further, the electric power generated by first motor generator 200 using the driving force of engine 100 is directly supplied to second motor generator 400.

  The traveling power is calculated by ECU 1000 according to a map having parameters such as the accelerator pedal opening (accelerator opening) and the vehicle speed operated by the driver, for example. That is, in the present embodiment, the traveling power of the hybrid vehicle represents the power required by the driver. Note that the method of calculating the traveling power is not limited to this. In the present embodiment, the unit of power is kW (kilowatt).

  The hybrid vehicle is controlled so that traveling power is shared by engine 100 and second motor generator 400. For example, if the first motor generator 200 does not generate power, the sum of the output power of the engine 100 and the output power of the second motor generator 400 is controlled to be substantially the same as the traveling power. Therefore, when the output power of engine 100 is zero, the output power of second motor generator 400 is controlled to be substantially the same as the traveling power. When the output power of second motor generator 400 is zero, control is performed so that the output power of engine 100 is substantially the same as the traveling power.

  When driving engine 100, for example, the higher the vehicle speed, the lower the output torque of second motor generator 400, and the ratio of the output power of engine 100 to the traveling power is increased. As an example, when the vehicle speed is higher than the threshold value, the output torque of the second motor generator 400 is reduced to zero, and the hybrid vehicle runs using only the driving force of the engine 100. The output power control mode is not limited to this.

  Output shaft rotational speed (engine rotational speed) NE and output torque of engine 100 are determined according to a first operating line indicated by a broken line and a second operating line indicated by a solid line in FIG. The first operation line and the second operation line indicate the relationship between the engine speed NE and the output torque. That is, the first operating line and the second operating line define the operating point of engine 100. The first operation line and the second operation line are predetermined by the developer based on results of experiments and simulations. The second operating line has a higher engine speed NE when realizing the same output power than the first operating line.

  The engine speed NE and the output torque of the engine 100 are determined as the intersection of the first operating line or the second operating line and an equal power line indicating the output power of the engine 100 determined according to the operation of the driver. That is, the engine speed NE of the engine 100 is a speed that realizes the output power of the engine 100 determined according to the operation of the driver on the first operation line or the second operation line.

  Therefore, when shifting from the state of driving engine 100 according to the first operating line to the state of driving engine 100 according to the second operating line, for example, while maintaining the output power of engine 100, the first operating line The engine speed NE is increased from the determined speed to the speed determined by the second operating line.

  As an example, when the output power of the engine 100 increases as the output torque of the second motor generator 400 decreases, the output power of the engine 100 increases once along the first operating line and then increases. While maintaining the subsequent output power, the engine speed NE is increased from the speed determined by the first operating line to the speed determined by the second operating line.

  A one-dot chain line in FIG. 6 is an optimum fuel consumption line determined so that the fuel consumption is optimized. In order to improve fuel consumption, it is preferable to drive at an engine speed NE and output torque close to the optimum fuel consumption line. As is apparent from FIG. 6, if the output power of the engine 100 is the same, the engine speed NE of the first operating line is closer to the optimal fuel consumption line than the engine speed NE of the second operating line. That is, the second operation line is further away from the optimum fuel consumption line than the first operation line. Therefore, the fuel efficiency is improved by driving engine 100 in accordance with the first operation line rather than the second operation line.

  For example, in the state where the second motor generator 400 is zero, the second operating line indicates the generation of sound due to the collision of the gear teeth of the power split mechanism 300 or the transmission 500, and the fluctuation of the output torque of the engine 100. Used to suppress by making it smaller.

  That is, when engine 100 is driven with engine speed NE and output torque determined by the second operating line, fluctuations in output torque of engine 100 are reduced. Therefore, the sound generated when the gear teeth collide is reduced. The second operation line is determined so that such a function can be realized.

  In the present embodiment, as an example, in a state where second motor generator 400 does not output torque (a state where torque is zero), or in a state where torque is near zero (within a predetermined range including zero), Engine 100 is driven at the engine speed NE and the output torque determined according to the second operation line.

  On the other hand, it is not preferable from the viewpoint of fuel efficiency to always drive engine 100 according to the second operating line. Therefore, the contact between the gear teeth of power split mechanism 300 or transmission 500 can be maintained by a state in which sound due to the collision of the gear teeth hardly occurs, for example, the torque output from second motor generator 400. In the state, it is preferable to drive engine 100 with engine speed NE and output torque determined by the optimum fuel consumption line.

  However, when the engine rotational speed NE is increased from the rotational speed determined by the optimal fuel consumption line to the rotational speed determined by the second driving line, if the increase amount of the engine rotational speed NE is large, the driving sound of the engine 100 may increase rapidly. . The sudden increase in driving sound can give the driver a feeling of strangeness. Therefore, in this embodiment, in order to reduce the amount of increase in driving sound, as an example, the state where the second motor generator 400 outputs torque (the state where the output torque is greater than zero), or the second motor generator 400 In a state larger than the threshold value (greater than zero), the engine 100 is driven at the engine speed NE and the output torque determined according to the first operation line in which the engine speed NE is higher than the optimum fuel consumption line at the same output power. . The first operating line is determined such that the amount of increase in driving sound falls within an allowable range.

  As shown in FIG. 7, the first driving line is closer to the optimum fuel consumption line as the vehicle speed is higher. Therefore, the first driving line is more largely separated from the second driving line as the vehicle speed is higher. In other words, the engine speed NE determined by the first operating line is further away from the engine speed NE determined by the second operating line as the vehicle speed increases. Therefore, as the vehicle speed increases, the amount of increase in the engine speed NE when the output torque of the second motor generator 400 decreases increases. As a result, the engine speed NE before the increase, that is, the engine operating point determined in a state where the second motor generator 400 outputs torque is brought closer to the optimum fuel consumption line. Therefore, it can contribute to the improvement of fuel consumption. Further, when the vehicle speed is high, such as when the vehicle speed is high, it is difficult for the driver to feel uncomfortable even if the amount of increase in the engine speed NE is large. As a result, it is possible to suppress deterioration in fuel consumption without increasing the uncomfortable feeling given to the driver when the engine speed NE is increased.

  The higher the vehicle speed, the greater the distance between the first driving line and the second driving line. Alternatively, as shown in FIG. 8, the higher the engine speed NE, the closer the first driving line to the optimum fuel consumption line. Also good. In other words, the first operating line may be further separated from the second operating line as the engine speed NE is higher. That is, the engine rotational speed NE determined by the first operating line is further separated from the engine rotational speed NE determined by the second operating line as the engine rotational speed NE is higher. Even if it does in this way, deterioration of a fuel consumption can be suppressed, without enlarging the discomfort given to a driver | operator when increasing the engine speed NE.

  Furthermore, when increasing the engine speed NE, the engine speed NE may be increased faster as either the vehicle speed or the engine speed NE is higher. As a result, the engine speed NE can be quickly increased before sound is generated in the gear or the like as the output torque of the second motor generator 400 decreases. Therefore, the generation of sound can be more effectively suppressed.

  In the present embodiment, the higher the vehicle speed or the engine speed, the larger the first driving line is away from the second driving line, but in all the driving regions, the higher the vehicle speed or engine speed, The first operating line may not be further separated from the second operating line.

  With reference to FIG. 9, a process executed by ECU 1000 in the present embodiment will be described. The processing described below may be realized by software, may be realized by a hard wafer, or may be realized by cooperation of software and a hard wafer.

  In step (hereinafter, step is abbreviated as S) 100, ECU 1000 detects the vehicle speed based on the output shaft speed of transmission 500, for example.

  In S102, ECU 1000 selects the first operating line according to the vehicle speed. As the vehicle speed increases, the first driving line that is farther away from the second driving line is selected.

  In S104, ECU 1000 drives engine 100 with engine speed NE and output torque determined using the first operating line. As described above, in the present embodiment, as an example, in the state where second motor generator 400 outputs torque, or in the state where output torque is larger than the threshold value, the engine speed determined according to the first operating line. Engine 100 is driven by NE and output torque.

  In S106, ECU 1000 determines whether or not the output torque of second motor generator 400 has decreased. For example, it is determined whether or not the output torque of second motor generator 400 has decreased to zero or a predetermined range including zero. Since ECU 1000 itself sets the output torque of second motor generator 400, whether or not the output torque of second motor generator 400 has decreased is determined by the output torque of second motor generator 400 set by ECU 1000 itself. Judgment based on.

  When the output torque of second motor generator 400 decreases (YES in S106), the process proceeds to S108. If not (NO in S106), the process returns to S100.

  In S108, ECU 100 drives engine 100 with engine rotational speed NE and output torque determined using the second operating line. Therefore, the engine speed NE is increased from the rotational speed determined using the first operating line to the rotational speed determined using the second operating line.

  As described above, according to the present embodiment, the increase amount of the engine speed NE is increased in a state where the vehicle speed or the engine speed NE is high, that is, in a state where the noise accompanying the traveling of the vehicle is large. Thereby, the engine speed NE before being increased can be made as low as possible. Therefore, it can contribute to the improvement of fuel consumption. Further, in a state where the noise accompanying the traveling of the vehicle is large, even if the amount of increase in the driving sound of the engine 100 is large, it is difficult for the driver to feel uncomfortable. As a result, it is possible to suppress deterioration in fuel consumption without increasing the uncomfortable feeling given to the driver when the engine speed NE is increased.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  100 Engine, 200 First motor generator, 300 Power split mechanism, 400 Second motor generator, 500 Transmission, 802 Crank angle sensor, 1000 ECU.

Claims (6)

An engine driving device mounted on a vehicle provided with an electric motor as a driving source,
Drive means for driving the engine at a first output shaft rotational speed in a state where the electric motor outputs torque;
An increase means for increasing the output shaft rotational speed of the engine from the first output shaft rotational speed to the second output shaft rotational speed when the torque of the electric motor decreases,
The engine drive device is configured such that the first output shaft rotational speed is further separated from the second output shaft rotational speed as either the vehicle speed or the output shaft rotational speed is higher.   2. The engine drive device according to claim 1, wherein the increasing means increases the output shaft rotational speed faster as one of the vehicle speed and the output shaft rotational speed is higher.   2. The engine according to claim 1, wherein the increasing means increases the output shaft speed of the engine from the first output shaft speed to a second output shaft speed while maintaining the output power of the engine. Drive device. The output power of the engine is determined according to the operation of the driver,
The first output shaft rotational speed realizes an output power determined in accordance with a driver's operation on a predetermined first line indicating a relationship between the output shaft rotational speed of the engine and an output torque. The number of revolutions,
The second output shaft rotational speed indicates the relationship between the output shaft rotational speed of the engine and the output torque, and the second output shaft rotational speed at the same output power is higher than that of the first line. The engine drive device according to claim 1, wherein the engine speed is a rotational speed that realizes output power determined according to a driver's operation on a line.   5. The engine drive device according to claim 4, wherein the first line is further away from the second line as the vehicle speed or the output shaft rotational speed is higher. 6. An engine driving device mounted on a vehicle provided with an electric motor as a driving source,
Means for driving the engine according to a first operating line defining an operating point of the engine in a state where the electric motor outputs torque;
Means for driving the engine in accordance with a second operating line that defines an operating point of the engine that is further away from the optimal fuel consumption line than the first operating line when the torque of the electric motor decreases. ,
The first drive line is an engine drive device that is closer to the optimum fuel consumption line as either the vehicle speed or the output shaft speed is higher.

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