JP2006188960A - Vehicle control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To quickly accelerate an engine, when a re-acceleration request is generated before stopping the engine, after stopping an automatic stopping condition. <P>SOLUTION: A re-acceleration request detecting means is arranged for detecting the re-acceleration request of a driver generated up to stopping the engine after starting automatic stopping control of the engine. A control means ignites a stopping time exhaust stroke cylinder and a stopping time expansion stroke cylinder in this order when detecting the re-acceleration request. The stopping time expansion stroke cylinder can be quickly moved to the compression top dead center by torque generated by the stopping time exhaust stroke cylinder. Next, due to transferring to an expansion stroke by burning an air-fuel mixture generated in this stopping time expansion stroke cylinder by igniting the stopping time expansion stroke cylinder, re-acceleration operation can be quickly performed thereafter. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a vehicle control device, and more particularly to a vehicle control device configured to restart an engine when a restart condition is satisfied after the engine is stopped.

In recent years, to reduce fuel consumption and reduce CO ₂ emissions, the engine is automatically stopped temporarily when idling, and then the engine is automatically restarted when restart conditions such as start operation are established. Automatic stop control, so-called idle stop control technology has been developed. The restart at the time of the idle stop control requires a quickness to immediately start the engine in accordance with the start operation of the vehicle or the like, but the engine output by the starter motor is generally performed conventionally. According to the method of restarting the engine through cranking that drives the shaft, there is a problem that it takes a considerable time to complete the start-up.

Therefore, as a start control device suitable for restarting the idle stop control, when the operation state of the engine satisfies the automatic stop condition during the operation of the spark ignition engine that forms the air-fuel mixture by the fuel injection of the fuel injection valve In the engine automatic stop / start control device that automatically starts the engine when the automatic start condition is satisfied, the intake air is sucked in the compression stroke when the engine is automatically stopped immediately before the engine is automatically stopped. By injecting fuel into the combustion chamber of a cylinder that is estimated to be in a state where both the valve and the exhaust valve are closed, the combustion chamber of the cylinder is brought into an air-fuel mixture state capable of spark ignition when the engine is automatically stopped. Is known (see, for example, Patent Document 1).
JP 2001-342876 A

  By the way, after the automatic stop control is started, there is a case where an acceleration request (such an acceleration request before the engine stops) is referred to as “re-acceleration request” in this specification before the engine stops. In such a case, conventionally, it has been necessary to wait for the phase to change until the cylinder that should start combustion first reaches the second half of the compression stroke among the cylinders that are about to enter the stopped state. For this reason, the driver may feel uncomfortable or uncomfortable during the waiting time.

  The present invention has been made in view of the above problems, and provides a vehicle control apparatus capable of accelerating an engine quickly when a re-acceleration request is made before the engine stops after the automatic stop condition stops. The issue is to provide.

  In order to solve the above problems, the present invention provides a fuel injection means for injecting fuel to an intake port of a spark ignition engine, and an ignition for igniting an air-fuel mixture in a cylinder generated by the fuel injected into the intake port. Means, crank angle detection means for detecting the crank angle of the engine, accelerator operation detection means for detecting the driver's accelerator operation, brake operation detection means for detecting the driver's brake operation, and the crank angle detection means, When it is determined that the engine automatic stop condition is satisfied based on the detection of the accelerator operation detection means and the brake operation detection means, the engine is automatically stopped and the engine is started when the automatic start condition is satisfied. The fuel injection means and the control means for controlling the ignition means, so as to automatically start the automatic stop control. Thus, the cylinder that stops in the expansion stroke at the time of stop is estimated as the expansion stroke cylinder at the time of stop, and the restarting fuel is injected into the expansion stroke cylinder at the time of stop. And a reacceleration request detecting means for detecting a reacceleration request of a driver that has occurred between the start of the automatic engine stop control and the stop of the engine. After starting the automatic stop control, fuel is injected into the intake port of the stop exhaust stroke cylinder which becomes the exhaust stroke at the stop before the fuel injection to the stop expansion stroke cylinder, while the re-acceleration request is detected In this case, the vehicle control apparatus is characterized in that the stop exhaust stroke cylinder and the stop expansion stroke cylinder are ignited in this order. In this aspect, when the automatic stop condition is satisfied after the vehicle starts running, the stop expansion stroke cylinder that becomes the expansion stroke when the engine is stopped immediately after the automatic stop control is started and immediately before the engine is stopped. Fuel is injected into the intake port and the intake port of the exhaust stroke cylinder at the time of stop which becomes an exhaust stroke. Furthermore, a re-acceleration request detecting means is provided for detecting a re-acceleration request of a driver that has occurred between the start of the automatic engine stop control and the engine stopping. When a re-acceleration request is detected, the stop Since the exhaust stroke cylinder and the stop expansion stroke cylinder are ignited in this order, the stop expansion stroke cylinder is quickly moved to the compression top dead center with the torque generated by the stop exhaust stroke cylinder. It becomes possible to make it. Next, by igniting the stop expansion stroke cylinder, the air-fuel mixture generated in the stop expansion stroke cylinder can be burned and shifted to the expansion stroke, and thereafter, the re-acceleration operation is promptly performed. Can do.

  In a preferred aspect, the control means detects an engine speed lower than a preset target speed in a state where a reacceleration request is not detected after being injected into the intake port of the exhaust stroke cylinder at the time of stop. In this case, when the stop-time exhaust stroke cylinder shifts to the expansion stroke, the stop-time exhaust stroke cylinder is ignited. In this aspect, even when the engine speed is less than the assumed target speed, the mixture of the exhaust stroke at the stop time that has shifted to the expansion stroke can be burned to generate torque, so that the final top dead It is possible to reliably position the expansion stroke cylinder at the stop in the expansion stroke after the point shift. In addition, since the ignition stroke cylinder is ignited when the stop stroke shifts to the expansion stroke after fuel injection, it is possible to prevent the unburned fuel that has flowed into the stop exhaust stroke cylinder from flowing out downstream of the exhaust port. become.

  In a preferred aspect, the control means, after being injected into the intake port of the exhaust stroke cylinder at the time of stop, when an engine speed equal to or higher than a preset target speed is detected in a state where a reacceleration request is not detected In this case, when the stop exhaust stroke cylinder shifts to the compression stroke, the stop exhaust stroke cylinder is ignited. In this mode, the piston in the exhaust stroke at the time of stoppage that has shifted to the compression stroke is pushed down and reverse torque is generated, so that the engine speed is quickly brought close to the target speed of the automatic stop control and the desired phase is reached. It becomes possible to stop each cylinder. Also in this aspect, it is possible to prevent unburned fuel that has flowed into the stop-time exhaust stroke cylinder from flowing out downstream of the exhaust port.

  In a preferred embodiment, there is provided a drive motor for driving the output shaft of the engine based on the control of the control means, and the control means ignites the exhaust stroke cylinder at the stop when the re-acceleration request is not detected, and then the engine speed Is different from the target rotational speed, the drive motor is driven so that the engine rotational speed becomes equal to the target rotational speed. In this aspect, even if the engine speed is excessive or insufficient with respect to the target speed by igniting the exhaust stroke cylinder at the time of stop when the reacceleration request is not detected, the output shaft of the engine Since the rotation of the cylinder can be assisted by the drive motor, each cylinder can be surely stopped at an intended phase with an appropriate torque.

  As described above, according to the present invention, when a reacceleration request is detected, the stop exhaust stroke cylinder and the stop expansion stroke cylinder are ignited in this order. By igniting the stop exhaust stroke cylinder, the stop expansion stroke cylinder can be quickly moved to the compression top dead center by the torque generated by the stop exhaust stroke cylinder, and the reacceleration operation can be performed quickly. Therefore, there is a remarkable effect that it is possible to realize a quick reacceleration operation without causing the driver to feel uncomfortable or uncomfortable when the reacceleration is requested.

  1 and 2 show a schematic configuration of an engine 1 according to an embodiment of the present invention. In these drawings, the engine 1 is provided with a plurality of cylinders 2. Each cylinder 2 is fitted with a piston 3 to form a combustion chamber 4 thereabove. The piston 3 is connected to the crankshaft 5 via a connecting rod (not shown).

  The combustion chamber 4 of the cylinder 2 is equipped with a spark plug 13 at the top, and an intake port 6 and an exhaust port 7 are opened. A fuel injection valve 8 is provided in the intake port 6. This fuel injection valve 8 incorporates a needle valve and a solenoid (not shown), and when a pulse signal is input, the fuel injection valve 8 is driven and opened for a time corresponding to the pulse width when the pulse is input. A corresponding amount of fuel is injected into the intake port 6.

  The intake port 6 is provided with an intake valve 6a, and the exhaust port 7 is provided with an exhaust valve 7a. These intake valve 6a and exhaust valve 7a are driven by a valve operating mechanism having a camshaft or the like. The opening / closing timings of the intake valve 6a and the exhaust valve 7a of each cylinder 2 are set so that each cylinder 2 performs a combustion cycle with a predetermined phase difference.

  An intake passage 9 and an exhaust passage 10 are connected to the intake port 6 and the exhaust port 7. A throttle valve 12 made up of a rotary valve is disposed in the intake passage 9. The throttle valve 12 is driven by an actuator 12a. Further, a crank angle sensor 14 for detecting the rotation angle of the crankshaft 5 of the engine 1 is provided.

  As shown in FIG. 2, the crankshaft 5 is provided with a transmission 16 that changes the rotation of the engine 1 and transmits it to the wheels 15 at one end thereof, and a restart device for the engine 1 at the other end. It is arranged. The restart device includes a restart motor 20 that is rotationally driven by electric power supplied from a battery 18 mounted on a vehicle via an inverter 19, and a chain that transmits the driving force of the restart motor 20 to the crankshaft 5. Or it has the power transmission mechanism 21 which has a belt. In the illustrated embodiment, the restart motor 20 constitutes a drive motor. On the other hand, a starter motor 25 that is fed by a power feeding system different from the battery 18 is connected to the transmission 16 via a gear mechanism 26, and is driven by the starter motor 25 during cold start. It has become so.

  Unlike the general starter motor 25, the restart motor 20 is configured to be able to change the torque. Therefore, as will be described later, when executing engine assist control, it is possible to perform engine motor assist with necessary and sufficient power. The restart motor 20 has a power generation function and is configured to be able to store power in the battery 18 via the inverter 19.

  Then, when the engine 1 is restarted, the restart motor 20 is activated to drive the crankshaft 5 in response to a control signal output from the ECU (engine control unit) 30 described below. The restart motor 20 is provided with a rotation angle sensor 22 that detects the rotation angle.

  FIG. 3 is a block diagram of a control device according to an embodiment of the present invention.

  Referring to FIG. 3, ECU 30 is a unit configured by a CPU, a memory, an input / output device, and the like. The ECU 30 includes an accelerator sensor 32 that detects the depression state of the accelerator pedal, a shift position sensor 33 that detects the operation position of the shift lever, and an ignition switch that is turned ON / OFF according to the operation of the ignition key by the driver. 34, a brake switch 35 for detecting the depression state of the brake pedal, and a battery remaining amount sensor 36 serving as a battery capacity detecting means for detecting the remaining amount of the battery according to the voltage of the battery 18, respectively. It is designed to be entered.

  Further, the ECU 30 includes a crank angle sensor 14 that detects the engine speed N and the crank angle CA, a rotation angle sensor 22 that detects the rotation angle of the restart motor 20, and the coolant temperature or lubricating oil temperature of the engine 1. Based on the engine temperature sensor 37 for detecting the in-cylinder temperature of the engine 1, the intake air temperature sensor 38 for detecting the intake air temperature, the air flow sensor 39 for detecting the intake air amount, and the intake pipe negative for detecting the negative pressure in the intake pipe. Detection signals respectively output from the pressure sensor 40 are input.

  The ECU 30 is connected with an actuator 12a of the throttle valve 12, a fuel injection valve 8 as a fuel injection means, a spark plug 13 as an ignition means, an inverter 19, and a starter motor 25 as control elements. While controlling these control elements during operation, it is determined whether or not the automatic stop condition is satisfied, and when the automatic stop condition is satisfied, the control element is controlled based on the input from the input element so that the engine 1 automatically stops. The control means for controlling is functionally configured.

  FIG. 4 is a time chart during the automatic stop control of the engine 1.

  Referring to FIG. 4, in the automatic stop control by ECU 30, ECU 30 determines whether or not an automatic stop condition for engine 1 is satisfied according to output signals from shift position sensor 33, brake switch 35, battery remaining amount sensor 36, and the like. At a timing when it is confirmed that the automatic stop condition is satisfied, a step of first setting and stabilizing the engine speed N to a value higher than the normal idle speed is executed. For example, in an engine in which the normal idle speed is set to 650 rpm (the automatic transmission is in the drive range), the above value is set to about 810 rpm (the automatic transmission is in the neutral range).

  Next, the fuel injection for driving is stopped at the timing when the engine speed N is stabilized (hereinafter referred to as “driving fuel for driving”), and the engine speed N is set based on an experiment conducted in advance from this timing. The reference rotational speed R (for example, 260 rpm) is set to be lowered. For this control, the memory of the ECU 30 stores a reference rotational speed R set based on an experiment or the like, and the cylinder in the expansion stroke when the engine rotational speed N becomes equal to the reference rotational speed R. 2 is specified as the stop-time expansion stroke cylinder (first cylinder (# 1 in the illustrated example)), and the cylinder 2 in the exhaust stroke is specified as the stop-time exhaust stroke cylinder (second cylinder (# 2) in the illustrated example). . For example, the first to fourth cylinders (# 1 to # 4) are provided, and the first cylinder (# 1), the third cylinder (# 3), the fourth cylinder (# 4), and the second cylinder (# 2). In the four-cylinder four-cycle engine configured to perform combustion in the order of (), it is assumed by experiments that the engine 1 is stopped after about two rotations after the rotation speed N reaches 500 rpm. In this case, 500 rpm is set as the reference rotation speed R, and the cylinder in the expansion stroke at the time t0 when the rotation speed reaches this rotation speed is specified as the stop expansion stroke cylinder, and the cylinder in the exhaust stroke is specified as the stop exhaust stroke cylinder. . In the illustrated example, the ECU 30 injects fuel (hereinafter referred to as “control fuel”) into the intake port 6 of the stop-time exhaust stroke cylinder at this time point t0 (see F1 in FIG. 4). This control fuel is for contributing to the reacceleration control of the engine 1 when a reacceleration request to be described later is requested.

  On the other hand, after the time t1 when the crank angle CA of the stop expansion stroke cylinder becomes 540 ° (ATD-540 deg) before the compression top dead center TDC, the fuel to the intake port 6 of the stop expansion stroke cylinder (hereinafter, “ (Referred to as F2 in FIG. 4). The restart fuel is used to contribute to restart of the engine 1 by being burned when the restart request of the engine 1 is made after the engine is stopped.

  Further, in the control described later, when a predetermined condition is satisfied, a cylinder that becomes a compression stroke at the time of stop (hereinafter referred to as a compression stroke at the time of stop) after a time point t2 when the crank angle CA becomes 360 ° (ATD-360 deg). Fuel is injected into the intake port 6 of the cylinder (referred to as F31 in FIG. 4).

  Note that the cylinder that is in the expansion stroke when the engine 1 is stopped is determined by determining the cylinder that is in the expansion stroke at the time t0 when the engine rotation speed N becomes the reference rotation speed R set based on the experiment conducted in advance. Instead of the configuration specified, the rotational energy A is calculated from the rotational speed of the crankshaft 5 when the engine rotational speed N reaches a predetermined value, and this rotational energy A and one stroke of each cylinder (crank Based on the loss energy B lost during the rotation of the shaft 5 by 180 °, the rotation amount from the time t0 until the engine 1 stops may be obtained by calculation. The loss energy B is obtained by adding the pumping loss of the engine 1, the mechanical resistance of the rotating part, and the lost due to compression leakage of each cylinder.

  The fuel injection amount for restart is adjusted according to the battery remaining amount detected by the battery remaining amount sensor 36, and when the battery remaining amount is small, the fuel injection amount becomes a smaller value than when it is large. Is set.

  Further, the ECU 30 determines whether or not the restart condition is satisfied according to the output signal of each sensor when the engine 1 is in the automatic stop state, and when it is confirmed that the restart condition is satisfied, the restart motor 20 And the fuel-air mixture generated by fuel being injected into the cylinder immediately before the engine 1 is stopped, and fuel is sequentially injected into the cylinders in the intake stroke and the exhaust stroke when the engine 1 is restarted. The engine 1 is automatically restarted by igniting at a predetermined timing.

  Further, when the restart control of the engine 1 is executed, the stop duration from the stop time t3 of the engine 1 to the restart time t4 is measured, and the driving torque of the restart motor 20 is determined based on the stop duration. It is configured to be adjusted. That is, the time until the restart condition is satisfied after the engine 1 is automatically stopped by the timer provided in the ECU 30 is measured as the stop duration, and when this stop duration is long, In comparison, the driving torque of the restart motor 20 is set to a small value.

  Further, when it is detected that the ignition switch 34 is turned off by the driver while the engine 1 is automatically stopped, the air-fuel mixture generated by injecting restart fuel at a predetermined timing is detected. The control for igniting is executed.

  On the other hand, the present embodiment is configured such that the restart motor 20 is operated under the conditions shown in the control flow to be described later when there is a request for reacceleration of the engine 1 even during the automatic stop control of the engine 1. ing. The engine reacceleration request can be detected, for example, by detecting that the driver has depressed the accelerator pedal after the automatic stop control.

  Next, automatic stop control in the present embodiment will be described with reference to FIG.

  FIG. 5 is a flowchart of automatic stop control in the present embodiment.

  Referring to FIG. 5, in the present embodiment, first, ECU 30 reads detection signals output from sensors and switches as input elements (step S1), and whether or not an automatic stop condition for engine 1 is satisfied. Is determined (step S2). Specifically, in a state in which a predetermined engine speed is detected, the ON state of the brake switch 35 continues for a predetermined time, and the remaining battery level is equal to or higher than a preset first reference value. When it is confirmed, it is determined that the automatic stop condition of the engine 1 is satisfied, and when even one of the above requirements is not satisfied, it is determined that the automatic stop condition is not satisfied. ing.

  When the automatic stop condition of the engine 1 is not satisfied, the ECU 30 executes normal fuel injection control and ignition control according to the engine speed and the intake air amount (step S3).

  On the other hand, when the automatic stop condition of the engine 1 is satisfied, the ECU 30 executes the fuel cut for operation from the fuel injection valve 8 and stops ignition of the air-fuel mixture by the spark plug 13 in order to automatically stop the engine 1. (Step S4).

  Next, the ECU 30 calculates the position at which each cylinder stops from the crank angle sensor 14 (step S5), and after the reference rotational speed R has elapsed, the stop exhaust stroke cylinder and the stop expansion stroke cylinder are in the first half of the expansion stroke, respectively. The fuel is injected at the timing of reaching (steps S6 and S7, see F1 and F2 in FIG. 4).

  Thereafter, it is determined whether or not there is a reacceleration request (step S8). If there is a reacceleration request, the process proceeds to a reacceleration request control subroutine in step S20. If there is no reacceleration request, an engine stop control subroutine (step S30) is executed. Then, the process ends.

  Next, the engine re-acceleration request control subroutine (step S20) will be described. FIG. 6 is a flowchart of an engine reacceleration request control subroutine, and FIG. 7 is a time chart based on the flowchart of FIG.

  6 and 7, when there is a request for reacceleration of the engine, the ECU 30 detects the crank angle CA at the time of the reacceleration request (step S200), and then stops the compression stroke cylinder (third cylinder ( # 3)) is injected (step S201; see F31 in FIG. 4).

  Next, the ECU 30 waits for the stop-time exhaust stroke cylinder (second cylinder (# 2)) to move between the compression top dead center and the first half of the expansion stroke (step S202), and the stop-time expansion stroke cylinder is compressed. When the cylinder moves from the top dead center during the first half of the expansion stroke, the cylinder is ignited (step S203).

  Thereafter, the ECU 30 injects fuel into the fourth cylinder (# 4) (step S204). Further, the ECU 30 waits for the stop expansion stroke cylinder to transition from the compression top dead center to the first half of the expansion stroke (step S205), and ignites when the stop expansion stroke cylinder shifts to this phase (step S205). S206). Subsequently, it waits for the stop-time compression stroke cylinder to shift from the compression top dead center to the first half of the expansion stroke (step S207), and ignites when the stop-time compression stroke cylinder shifts to this phase (step S208). . Thereafter, each cylinder is synchronously injected and ignited (step S209).

  As described above, in the present embodiment, after the automatic stop control of the engine 1 is started, the fuel is also injected into the stop-time exhaust stroke cylinder immediately before the engine 1 is stopped. It is possible to ignite from the exhaust stroke cylinder when stopped. As a result, the engine can be accelerated very quickly when the reacceleration is requested.

  Next, stop control when there is no reacceleration request after the automatic stop control has started will be described in detail. FIG. 8 is a flowchart showing an engine stop control subroutine, and FIGS. 9 and 10 are time charts based on the flowchart of FIG.

  Referring to each figure, when the engine stop control subroutine (step S30) is started, first, ECU 30 determines whether or not detected engine speed (actual speed) N is below target speed L. (Step S31). Here, the target rotational speed L refers to a rotational speed set by an experiment or the like so that each cylinder 2 stops at a predicted phase when the engine 1 is stopped by automatic control. If the engine speed N is less than the target speed L, the control is as shown in the time chart of FIG.

  In this aspect, in order to increase the engine speed N to the target speed L, the engine waits for the stop-time exhaust stroke cylinder to reach the first half of the expansion stroke (step S32), and ignites when it reaches (step S33). . By this ignition, a positive torque acts on the engine 1 and the engine speed N reaches the target speed L.

  Here, the ECU 30 determines whether or not the engine speed N after ignition is equal to the target speed L (step S34). If the engine speed N is not equal, the engine 30 is driven by driving the restart motor 20. The rotation speed N is adjusted (step S35). In many cases, the engine speed N is higher than the target speed L due to ignition in step S33. In that case, the engine speed N is controlled to be equal to the target speed L by applying reverse torque by the restart motor 20. If the restart motor 20 has a power generation function, a power generation operation may be performed by the restart motor 20 in step S35 to apply a load to the engine 1.

  On the other hand, when the engine speed N is equal to or higher than the target speed L in step S31, the control is as shown in FIG.

  In this aspect, in order to reduce the engine speed N to the target speed L, the engine waits for the stop exhaust stroke cylinder to reach the latter half of the compression stroke (step S36), and ignites when it reaches (step S33). . By this ignition, reverse torque is generated in the engine 1 and the engine speed N reaches the target speed L.

  Also in this aspect, the ECU 30 determines whether or not the engine speed N after ignition is equal to the target speed L (step S34), and if not, by driving the restart motor 20 Then, the engine speed N is adjusted (step S35). In many cases, the engine speed N is lower than the target speed L due to ignition in step S33. In this case, a positive torque is applied by the restart motor 20, and thereafter, a reverse torque is applied in accordance with the engine speed N, so that the engine speed N is controlled to be equal to the target speed L. To do. Also in this aspect, when the restart motor 20 has a power generation function, in the phase in which the reverse torque is applied to the engine 1, the restart motor 20 performs a power generation operation and applies a load to the engine 1. May be.

  In the present embodiment, when the automatic stop condition is satisfied after the vehicle starts running, the stop-time expansion stroke cylinder that becomes the expansion stroke when the engine is stopped immediately after the start of the automatic stop control and immediately before the engine is stopped. The control fuel and the restart fuel are respectively injected into the intake port 6 and the intake port 6 of the exhaust stroke cylinder at the time of stop which becomes the exhaust stroke. Furthermore, a reacceleration request detecting means (accelerator sensor 32) is provided for detecting a reacceleration request of the driver that has occurred from the start of the automatic stop control of the engine 1 until the engine 1 is stopped. In this case, as described with reference to FIGS. 6 and 7, the stop exhaust stroke cylinder and the stop expansion stroke cylinder are ignited in this order, and therefore generated by the stop exhaust stroke cylinder. It becomes possible to quickly move the expansion stroke cylinder at the time of stop to the compression top dead center by the torque. Next, by igniting the stop expansion stroke cylinder, the air-fuel mixture generated in the stop expansion stroke cylinder can be burned and shifted to the expansion stroke, and thereafter, the re-acceleration operation is promptly performed. Can do.

  Further, in the present embodiment, the ECU 30 has an engine speed N lower than the target speed L set in advance in a state where the re-acceleration request is not detected after being injected into the intake port 6 of the exhaust stroke cylinder at the time of stop. When it is detected, when the stop-time exhaust stroke cylinder shifts to the expansion stroke, the stop-time exhaust stroke cylinder is ignited. For this reason, in the present embodiment, even when the engine speed N is less than the assumed target speed L, it is possible to generate torque by burning the air-fuel mixture in the stop-time exhaust stroke cylinder that has shifted to the expansion stroke. Therefore, it becomes possible to reliably position the expansion stroke cylinder at the time of stoppage after the final top dead center shift in the expansion stroke. In addition, since the ignition is performed when the stop-time exhaust stroke cylinder shifts to the expansion stroke after fuel injection, unburned control fuel flowing into the stop-time exhaust stroke cylinder is prevented from flowing downstream of the exhaust port 7. It is also possible to do.

  In this embodiment, the ECU 30 detects an engine speed N equal to or higher than a preset target speed L in a state where a re-acceleration request is not detected after being injected into the intake port 6 of the exhaust stroke cylinder at the time of stop. In this case, when the stop-time exhaust stroke cylinder shifts to the compression stroke, the stop-time exhaust stroke cylinder is ignited. For this reason, in the present embodiment, the piston in the stop-time exhaust stroke cylinder that has shifted to the compression stroke is pushed down, and reverse torque is generated, so that the rotational speed of the engine 1 is quickly brought close to the target rotational speed L of the automatic stop control. Each cylinder 2 can be stopped at the intended phase. Also in the present embodiment, it is possible to prevent the unburned control fuel that has flowed into the stop-time exhaust stroke cylinder from flowing out to the downstream side of the exhaust port 7.

  Further, in the present embodiment, a restart motor 20 that drives the crankshaft 5 of the engine 1 based on the control of the ECU 30 is provided, and the ECU 30 ignites the exhaust stroke cylinder at the stop when the reacceleration request is not detected. When the engine speed N is different from the target speed L, the restart motor 20 is driven so that the engine speed N becomes equal to the target speed L. For this reason, in the present embodiment, even when the engine speed N is excessive or insufficient with respect to the target speed L by igniting the exhaust stroke cylinder at the stop when the reacceleration request is not detected, Since the rotation of the crankshaft 5 of the engine 1 can be assisted by the restart motor 20, each cylinder 2 can be reliably stopped at an intended phase with an appropriate torque.

  As described above, according to this embodiment, when a reacceleration request is detected, the stop exhaust stroke cylinder and the stop expansion stroke cylinder are configured to ignite in this order. By igniting the stop exhaust stroke cylinder, the stop expansion stroke cylinder can be quickly moved to the compression top dead center by the torque generated by the stop exhaust stroke cylinder, and the reacceleration operation can be performed quickly. Therefore, there is a remarkable effect that it is possible to realize a quick reacceleration operation without causing the driver to feel uncomfortable or uncomfortable when the reacceleration is requested.

  The above-described embodiments are merely examples of preferred specific examples of the present invention, and the present invention is not limited to the above-described embodiments. It goes without saying that various modifications are possible within the scope of the claims of the present invention.

1 shows a schematic configuration of an engine according to an embodiment of the present invention. 1 shows a schematic configuration of an engine according to an embodiment of the present invention. It is a block diagram of the control apparatus by embodiment of this invention. It is a time chart at the time of automatic stop control of an engine. It is a flowchart of the automatic stop control in this embodiment. It is a flowchart of an engine reacceleration request control subroutine. It is a time chart based on the flowchart of FIG. It is a flowchart which shows an engine stop control subroutine. It is a time chart based on the flowchart of FIG. It is a time chart based on the flowchart of FIG.

Explanation of symbols

1 Engine 2 Cylinder 5 Crankshaft 6 Intake port 7 Exhaust port 8 Fuel injection valve 13 Spark plug 14 Crank angle sensor 18 Battery 19 Inverter 20 Restart motor 22 Rotation angle sensor 30 ECU
32 Acceleration sensor 35 Brake switch CA Crank angle L Target speed N Engine speed R Standard speed TDC Compression top dead center

Claims (4)

Fuel injection means for injecting fuel into the intake port of the spark ignition engine;
Ignition means for igniting an air-fuel mixture in a cylinder generated by fuel injected into the intake port;
Crank angle detecting means for detecting the crank angle of the engine;
An accelerator operation detecting means for detecting the driver's accelerator operation;
Brake operation detection means for detecting the driver's brake operation;
Based on the detection of the crank angle detection means, the accelerator operation detection means, and the brake operation detection means, if it is determined that the engine automatic stop condition is satisfied, the engine is automatically stopped and the automatic start condition The fuel injection means and the control means for controlling the ignition means are provided so that the engine is automatically started when the engine is satisfied, and the cylinder that stops in the expansion stroke at the time of stop is started by starting the automatic stop control. A control device for a vehicle that estimates a stroke cylinder and injects restart fuel into the stop expansion stroke cylinder while igniting the stop expansion stroke cylinder when the engine that has been automatically stopped is restarted.
Re-acceleration request detection means is provided for detecting a driver's re-acceleration request that has occurred between the start of the engine automatic stop control and the engine stop,
The control means, after starting the automatic stop control, injects fuel into the intake port of the stop exhaust stroke cylinder which becomes the exhaust stroke at the stop before the fuel injection to the stop expansion stroke cylinder. When a request for acceleration is detected, the vehicle control apparatus is characterized in that the stop-time exhaust stroke cylinder and the stop-time expansion stroke cylinder are ignited in this order. The vehicle control device according to claim 1,
The control means, after being injected into the intake port of the exhaust stroke cylinder at the time of stop, when an engine speed lower than a preset target speed is detected in a state where a reacceleration request is not detected, A control apparatus for a vehicle, characterized in that when a stop exhaust stroke cylinder shifts to an expansion stroke, the stop exhaust stroke cylinder is ignited. The vehicle control device according to claim 1 or 2,
The control means stops when an engine speed greater than a preset target speed is detected in a state where a reacceleration request is not detected after being injected into the intake port of the exhaust stroke cylinder at the time of stop. A control apparatus for a vehicle, characterized in that, when an hour exhaust stroke cylinder shifts to a compression stroke, the stop exhaust stroke cylinder is ignited. The vehicle control device according to any one of claims 1 to 3,
A drive motor for driving the output shaft of the engine is provided based on the control of the control means, and the control means ignites the exhaust stroke cylinder at the stop when the reacceleration request is not detected, and then the engine speed is the target speed. When the vehicle speed is different from the above, the drive motor is driven so that the engine rotational speed becomes equal to the target rotational speed.

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