JP2006194217A - Control device for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve vaporization of fuel used upon restarting. <P>SOLUTION: A supercharger is provided for supercharging an engine at a predetermined timing after starting automatic stop control. After the supercharging performed by the supercharger, fuel for restarting is injected into an intake port of a cylinder in the expansion stroke. When a cylinder temperature Tc is high, a driving motor is driven and the engine 1 is scavenged. After the cylinder temperature Tc is lowered, the engine 1 is supercharged. By the engine 1 being supercharged, evaporation of fuel injected into the cylinder in the expansion stroke during engine stop is improved, and restarting becomes easy. At the same time, when the cylinder temperature Tc of the engine 1 is high, the driving motor is driven, so that compression self-ignition due to supercharging can be prevented. <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, when there is a restart request after the automatic engine stop, it is necessary to improve the ignitability of the fuel injected in the process of the automatic stop control. However, in the case of a port injection type engine, there is a case in which vaporization of the fuel injected into the intake port in the cylinder is not promoted, and the ignitability becomes uncertain. For this reason, the behavior when the engine is restarted is unstable.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a vehicle control device that can ensure a restart operation of an engine after an automatic stop.

  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. The cylinder that stops in the expansion stroke at the time of stop is estimated as the expansion stroke cylinder at the stop, and the fuel for restart is injected into the intake port of the expansion stroke cylinder at the time of stop. A control device for a vehicle that ignites an expansion stroke cylinder is provided with a supercharger that supercharges intake air of an engine, and the control device prior to injecting fuel into an intake port of the expansion stroke cylinder during stoppage, A vehicle control device that operates a supercharger after an automatic stop condition is satisfied. In this aspect, after the automatic stop condition is satisfied, the supercharger is operated before fuel is injected for restarting the engine. Therefore, the filling amount of the stop expansion stroke cylinder is increased by the supercharging action. become. As a result, the vaporization of the restart fuel injected into the intake port of the stop expansion stroke cylinder is promoted, so that the ignitability of the air-fuel mixture in the stop expansion stroke cylinder at the time of restart is improved.

  In another aspect, there is provided in-cylinder temperature detecting means for detecting the in-cylinder temperature of the expansion stroke cylinder at the time of stop and inputting it to the control means, and the control means The operation of the turbocharger is prohibited. When the stop expansion stroke cylinder is in a high temperature state that is equal to or higher than a predetermined temperature, the restart fuel is likely to undergo compression self-ignition due to an increase in the charging amount due to the supercharging action. Therefore, in this aspect, the in-cylinder temperature detecting means detects the in-cylinder temperature of the stop expansion stroke cylinder and prohibits the operation of the supercharger based on the detected temperature, thereby compressing the self-compression cylinder in the stop expansion stroke cylinder. I try to prevent ignition.

  In another aspect, a drive motor for driving the output shaft of the engine is provided, and when the operation of the supercharger is prohibited, the control means drives the drive motor prior to injecting fuel into the intake port of the expansion stroke cylinder when stopped. Is to operate. In this aspect, scavenging of the engine is promoted by the drive motor assisting the operation of the engine at a high temperature at which the operation of the supercharger is prohibited. As a result, low temperature fresh air is introduced into the stop expansion stroke cylinder, and the stop expansion stroke cylinder is cooled. Therefore, it is possible to prevent compression self-ignition in the expansion stroke cylinder when stopped even at high temperatures.

  In a specific aspect, the control means operates the drive motor when the automatic stop operation is started, and stops the drive motor after the detected in-cylinder temperature becomes lower than a preset value. It operates the feeder. In this mode, the engine can be immediately cooled when the automatic stop control is started. Therefore, even when the in-cylinder temperature of the engine that has started the automatic stop control is high, compression self-ignition by supercharging is possible. Can be prevented.

  In another aspect, there is provided in-cylinder pressure detecting means for detecting an in-cylinder pressure of the stop expansion stroke cylinder and inputting the in-cylinder pressure to the control means, wherein the control means has an in-cylinder pressure of the stop expansion stroke cylinder of a predetermined value or more. In some cases, control is performed to reduce the throttle opening of the engine. In this aspect, it is possible to determine whether or not the cooling effect by the drive motor is sufficient based on the in-cylinder pressure of the expansion stroke cylinder at the time of stop. When the in-cylinder pressure of the stop expansion stroke cylinder is greater than or equal to a predetermined value, it is possible to reduce the throttle opening of the engine and reduce the filling amount to prevent compression self-ignition in the stop expansion stroke cylinder. become.

  As described above, according to the present invention, vaporization of the restart fuel injected into the intake port of the stop-time expansion stroke cylinder is promoted by supercharging, so that in the stop-time expansion stroke cylinder at the time of restart As a result of improving the ignitability of the air-fuel mixture, there is a remarkable effect that the restart operation of the engine after the automatic stop can be ensured.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a schematic configuration diagram of an entire vehicle control apparatus according to an embodiment of the present invention, and FIG. 2 is a schematic diagram of an engine employed in FIG.

  With reference to the drawings, the control device includes an engine 1. 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.

  As shown in FIG. 1, an electric supercharger 14 is provided on the upstream side of the intake passage 9. The electric supercharger 14 is provided with a compressor 16 driven by a motor 15, and an intercooler 17 is disposed downstream thereof. Further, a bypass passage 9 a that bypasses the compressor 16 is formed in the intake passage 9.

  Next, the engine 1 is provided with a crank angle sensor 20 that detects the rotation angle of the crankshaft 5. Further, the crankshaft 5 is provided with a transmission 22 for shifting the rotation of the engine 1 and transmitting it to the wheels 21 at one end thereof, and a restart device 24 for the engine 1 at the other end. . The restart device 24 transmits to the crankshaft the restart motor 25 that is rotationally driven by the electric power supplied from the battery 18 mounted on the vehicle via the inverter 19 and the restart motor 25. And a power transmission mechanism 26 having a chain or a belt. In the illustrated embodiment, the restart motor 25 is a specific example of a drive motor. The restart motor 25 has a power generation function, and electric power generated by the restart motor 25 is stored in a storage battery 18 a mounted on the battery 18.

  The restart motor 25 is activated to drive the crankshaft 5 in response to a control signal output from the ECU (engine control unit) 40 described below when the engine 1 is restarted. The restart motor 25 is provided with a rotation angle sensor 27 for detecting the rotation angle.

  A 12 V lead storage battery 29 is connected to the storage battery 18 a of the battery 18 via a DC / DC converter 28. The lead storage battery 29 is provided with a voltage sensor 30 that detects the voltage of the lead storage battery 29.

  Furthermore, a starter motor 31 is connected to the transmission 22 via a gear mechanism 32, and is driven by the starter motor 31 during cold start.

  The ECU 40 is a unit configured by a CPU, a memory, an input / output device, and the like. The ECU 40 includes an accelerator sensor 42 that detects the depression state of the accelerator pedal 41, a shift position sensor 43 that detects the operation position of the shift lever, and an ignition that is turned ON / OFF according to the operation of the ignition key by the driver. Each detection signal output from the switch 44, the brake switch 46 that detects the depression state of the brake pedal 45, and the battery remaining amount sensor 47 that detects the remaining amount of the battery according to the voltage of the battery 18 is input. It has become.

  The ECU 40 also includes a crank angle sensor 20 that detects the engine speed N and the crank angle CA, a rotation angle sensor 27 that detects the rotation angle of the restart motor 25, and a voltage sensor 30 that detects the voltage of the lead storage battery 29. An engine temperature sensor 48 that detects the temperature in the cylinder of the engine 1 based on the coolant temperature or the lubricating oil temperature of the engine 1, an intake air temperature sensor 49 that detects the intake air temperature, and an airflow sensor 50 that detects the intake air amount. In addition, detection signals output from the intake pipe negative pressure sensor 51 that detects the negative pressure in the intake pipe are input.

  Further, the ECU 40 includes, as control elements, 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, an electric supercharger 14, a transmission 22, a DC / DC A converter 28 and a starter motor 31 are connected to control these control elements during normal operation, determine whether an automatic stop condition is satisfied, and automatically stop the engine 1 when the automatic stop condition is satisfied. Thus, the control means for controlling the control element is functionally configured based on the input from the input element.

  FIG. 3 is a time chart during the automatic stop control of the engine 1, and FIG. 4 is a time chart showing a change state of the engine speed.

  Referring to FIGS. 3 and 4, in the automatic stop control by ECU 40, ECU 40 establishes an automatic stop condition for engine 1 in accordance with output signals from shift position sensor 43, brake switch 46, battery remaining amount sensor 47, and the like. At a timing when it is confirmed that the automatic stop condition is satisfied, a step of stabilizing the engine speed N at a value higher than the normal idle speed is first 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 40 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 expansion stroke cylinder at the time of stop (in the illustrated example, the first cylinder (# 1)). 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 a four-cylinder two-cycle engine configured to perform combustion in the order of (), it is assumed that it has been experimentally confirmed that the engine 1 stops 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 is reached is specified as the expansion stroke cylinder at the time of stop. In the illustrated example, the ECU 40 performs the intake of the stop expansion stroke cylinder after time t1 when the crank angle CA of the stop expansion stroke cylinder reaches 540 ° (ATD-540 deg) before the compression top dead center TDC. Fuel is injected into the port, and after the time t2 when the crank angle CA reaches 360 ° (ATD-360 deg), the fuel to the intake port 6 of the cylinder that becomes the compression stroke at the time of stop (hereinafter referred to as the compression stroke cylinder at the time of stop) (Hereinafter referred to as “restart fuel”). This restart fuel is for contributing to restart of the engine 1 by being burned when the restart request of the engine 1 is made after the engine is stopped.

  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 restart fuel injection amount is adjusted according to the battery remaining amount detected by the battery remaining amount sensor 47. When the battery remaining amount is low, the fuel injection amount is set to a smaller value than when it is large. Is done.

  Further, the ECU 40 determines whether or not the restart condition is satisfied according to the output signal of each sensor in the automatic stop state of the engine 1, and when it is confirmed that the restart condition is satisfied, the restart motor 25 Is operated, and the fuel-air mixture generated by fuel being injected into the cylinder immediately before the engine 1 is stopped is ignited, and when the engine 1 is restarted, fuel is sequentially injected into each cylinder in the intake stroke and the exhaust stroke. 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 T from the stop time t3 of the engine 1 to the restart time t4 is measured, and the restart motor 25 is driven based on the stop duration T. The torque 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 40 is measured as the stop duration T. When the stop duration T is long, the time is short. Compared to the case, the driving torque of the restart motor 25 is set to a small value.

  Further, when it is detected that the ignition switch 44 is turned off by the driver while the engine 1 is automatically stopped, the air-fuel mixture generated by injecting restart fuel is ignited at a predetermined timing. The control to perform is performed.

  In the present embodiment, the electric supercharger 14 is operated in the process of automatic stop control to achieve scavenging, and the vaporization of fuel injected in the process of automatic stop is promoted.

  FIG. 5 is a graph showing the relationship between the control time and the in-cylinder temperature of the electric supercharger 14 according to this embodiment.

  With reference to the figure, the memory of ECU 40 stores a control map used when the engine 1 is automatically stopped as described with reference to FIGS. This control map is created based on the results confirmed in advance by experiments, and is for determining the operation start timing Tm of the electric supercharger 14 based on the in-cylinder temperature Tc. The in-cylinder temperature Tc is determined based on the detection value of the temperature sensor 48. When the in-cylinder temperature Tc is less than a certain threshold value Tcs, the ECU 40 sets the operation start timing Tm of the electric supercharger 14 to 0, and supercharges the engine 1 in a flow to be described later. On the other hand, when the in-cylinder temperature Tc is equal to or higher than the threshold value Tcs, the operation start timing Tm of the electric supercharger 14 is set in proportion to the value, and the in-cylinder temperature Tc is set in detail as will be apparent from the flow described later. Accordingly, the engine 1 is configured to be cooled.

  FIG. 6 is a graph showing the relationship between the throttle opening Tvo and the in-cylinder pressure Pc according to this embodiment.

  Referring to FIG. 4, the memory of ECU 40 stores still another control map used when engine 1 is automatically stopped as described with reference to FIGS. This control map is created based on the results confirmed in advance in the experiment, and the drive timing T10 for driving the actuator 12a of the throttle valve 12 at the time of automatic stop according to the in-cylinder pressure Pc of each cylinder 2. For controlling the throttle opening Tvo. The in-cylinder pressure Pc is determined based on detection values of the crank angle sensor 20 and the temperature sensor 48. In the control map, a throttle opening region for maintaining the throttle opening Tvo as it is, a throttle opening reduction region for reducing the throttle opening Tvo according to the in-cylinder pressure Pc, and a throttle closing region for closing the throttle are set. Two threshold values Pcs and Pclt are set to partition each of these areas. In the illustrated example, a range where the in-cylinder pressure is less than the threshold value Pcs is defined as a throttle opening region, a range between the threshold value Pcs and less than Pclt is defined as a throttle opening reduction region, and a range equal to or greater than the threshold value Pclt is defined as a throttle blockage region.

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

  7 to 9 are flowcharts of the automatic stop control in the present embodiment. FIG. 10 is a timing chart based on the automatic stop control of FIGS.

  First, referring to FIGS. 7 and 10, in the present embodiment, first, ECU 40 reads detection signals output from sensors and switches as input elements (step S1), and the automatic stop condition of engine 1 is satisfied. It is determined whether or not (step S2). Specifically, in a state where a predetermined engine speed is detected, the ON state of the brake switch 46 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 40 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 40 sets the count time t for control to 0 (step S4), and then from the fuel injection valve 8 to automatically stop the engine 1. The fuel cut for operation is executed and the ignition of the air-fuel mixture by the spark plug 13 is stopped (step S5).

  Next, the operation start timing Tm of the electric supercharger 14 is determined from the control map based on the graph of FIG. 5 (step S6). Next, the ECU 40 compares the count time t with the operation start timing Tm of the electric supercharger 14, and after the automatic stop condition of the engine 1 is satisfied, the operation start timing Tm of the electric supercharger 14 set in step S7. It is determined whether or not the above has elapsed (step S7). As described with reference to FIG. 5, when setting the operation start timing Tm of the electric supercharger 14, it is assumed that the in-cylinder temperature Tc is in the cooling region and the count time t is set in step S <b> 6. When the operation start timing of the machine 14 is not reached, the ECU 40 operates the restart motor 25 (step S8) and waits for the count time t to reach the operation start timing Tm. Normally, the in-cylinder temperature Tc of the engine 1 is considerably high immediately after the start of the automatic stop control. Therefore, by adopting the control map based on FIG. 5 and performing the control flow of steps S6 and S7, the restart motor 25 is driven immediately when the automatic stop operation is substantially started.

  On the other hand, when the count time t has elapsed at the operation start timing Tm, the ECU 40 checks whether or not the restart motor 25 is operating (step S9), and if it is operating, stops the restart motor 25. After that (step S10), the electric supercharger 14 is operated (step S11). In the present embodiment, since the operation start timing Tm is set by the control map based on FIG. 5, if the in-cylinder temperature Tc is sufficiently low, the electric supercharger 14 is immediately operated to restart it more than necessary. There is an advantage that the starting motor 25 is not driven.

  Next, referring to FIGS. 8 and 10, ECU 40 waits for count time t to reach drive timing T10 for the throttle opening (step S14).

  When the count time t reaches the drive timing T10 of the throttle opening Tvo, the ECU 40 determines the throttle opening Tvo based on the control map described in FIG. 6 (step S15), and the determined throttle opening Tvo. Based on the above, the actuator 12a of the throttle valve 12 is driven (step S16). For this reason, in this embodiment, after the electric supercharger 14 is operated, the throttle opening Tvo is reduced or closed even when the in-cylinder temperature (in-cylinder pressure Pc) increases and compression self-ignition easily occurs. Thus, compression self-ignition can be suppressed.

  Next, the ECU 40 waits for the engine speed N to decrease below the reference rotational speed (step S17).

  Referring to FIGS. 9 and 10, when engine speed N is reduced below the reference rotational speed, ECU 40 calculates the position at which each cylinder 2 stops from crank angle sensor 20, and stops each cylinder. The position is estimated (step S18). After that, the system waits for the timing when the expansion stroke cylinder (first cylinder (# 1)) at the time of stopping reaches the first half of the expansion stroke (step S19), and injects fuel (step S20; see F1 in FIGS. 3 and 4).

  Further, after that, fuel is injected at the timing when the stop-time compression stroke cylinder (third cylinder (# 3)) reaches the first half of the exhaust stroke (steps S21 and S22; see F2 in FIGS. 3 and 4).

  After that, it waits for the count time t to elapse the stop timing Ts for stopping the electric supercharger 14 (step S23), and after the elapse, the electric supercharger 14 is stopped (step S24).

  Thereafter, the ECU 40 waits for the engine 1 to stop (step S25), and starts measuring the stop duration T from the stop point (step S26).

  FIG. 11 is a flowchart showing the control after the automatic stop.

  Referring to the figure, when engine 1 automatically stops, ECU 40 determines whether or not the driver has performed an OFF operation of ignition switch 44 (step S303).

  If it is determined NO in step S303 and it is confirmed that the ignition switch 44 is not turned off, it is determined whether or not the engine restart condition is satisfied (step S304). As the restart condition, the brake switch 46 is turned off, the brake negative pressure (intake pipe negative pressure) is less than a predetermined value, the stop duration T is more than a predetermined value, or If the remaining battery level V is less than the reference value or the like and one of these requirements is satisfied, it is determined that the engine restart condition is satisfied. When the engine restart condition is not satisfied, the process proceeds to step S303.

  When the restart condition of the engine 1 is satisfied, the driving torque of the restart motor 25 is set by reading it from a table not shown (step S305). The table for setting the drive torque corresponding to the measured value of the stop duration T is set based on the stop duration T. When the stop duration T is long, the drive torque is smaller than when it is short. Is set to a value. In addition, the restart motor 25 is operated at the time point t4 (see FIG. 3) when the restart condition is satisfied, and a predetermined amount of air-fuel mixture is generated by injecting fuel into the cylinders immediately before the engine is stopped. The engine is restarted by performing ignition SP1 and SP2 at the timing (step S306).

  Referring also to FIG. 3, fuel injections F3 and F4 are performed on the fourth cylinder in the intake stroke and the second cylinder in the exhaust stroke at the time t4 when the restart condition is satisfied (step S307), and these cylinders are compressed. After the ignition of the air-fuel mixture SP3 and SP4 is performed sequentially when the top dead center is reached (step S308), the measured value of the stop duration T is reset to 0 (step S309).

  On the other hand, if it is determined YES in step S303 and it is confirmed that the driver has turned off the ignition switch 44 with the intention of stopping, the first cylinder (# 1) that is in the expansion stroke when stopped And the ignition with respect to the air-fuel | gaseous mixture produced | generated by performing said fuel injection F1, F2 to the 3rd cylinder (# 3) used as a compression stroke is performed simultaneously (step S310), and a process is complete | finished.

  As described above, in the present embodiment, since the electric supercharger 14 is operated before fuel is injected for restarting the engine 1, the expansion stroke cylinder (# 1) at the time of stop is supercharged. As a result, the filling amount is increased. As a result, the vaporization of the restart fuel injected into the intake port 6 of the stop expansion stroke cylinder (# 1) is promoted, so that the air-fuel mixture in the stop expansion stroke cylinder (# 1) during the restart is reduced. Ignition is improved.

  Further, in the present embodiment, an engine temperature sensor 48 that detects the in-cylinder temperature Tc of the expansion stroke cylinder (# 1) at stop and inputs it to the ECU 40 is provided, and the ECU 40 detects that the detected in-cylinder temperature Tc is equal to or greater than a predetermined value. In this case, the operation of the electric supercharger 14 is prohibited. That is, when the stop expansion stroke cylinder (# 1) is in a high temperature state equal to or higher than a predetermined temperature, the restart fuel causes compression self-ignition due to an increase in the filling amount due to the supercharging action of the electric supercharger 14. It becomes easy. Therefore, in the present embodiment, the engine temperature sensor 48 detects the in-cylinder temperature Tc of the expansion stroke cylinder (# 1) at the time of stop, and prohibits the operation of the electric supercharger 14 based on the detected temperature Tc. The compression self-ignition in the expansion stroke cylinder (# 1) is prevented.

  In the present embodiment, the restart motor 25 that drives the crankshaft 5 of the engine 1 is provided, and the ECU 40, when the operation of the electric supercharger 14 is prohibited, is the intake port 6 of the stop expansion stroke cylinder (# 1). Prior to the fuel injection, the restart motor 25 is operated. Therefore, in this embodiment, scavenging of the engine 1 is promoted by the restart motor 25 assisting the operation of the engine 1 at a high temperature at which the operation of the electric supercharger 14 is prohibited. As a result, low temperature fresh air is introduced into the stop expansion stroke cylinder (# 1), and the stop expansion stroke cylinder (# 1) is cooled. Accordingly, it is possible to prevent the compression self-ignition in the stop-time expansion stroke cylinder (# 1) even at high temperatures.

  In the present embodiment, the control map based on FIG. 5 is used, and based on the flow described with reference to FIG. 7, the restart motor 25 is actuated when the automatic stop operation is substantially started, and the detected cylinder is detected. After the internal temperature Tc becomes lower than a preset value, the restart motor 25 is stopped and the electric supercharger 14 is operated. For this reason, in the present embodiment, the engine 1 can be immediately cooled when the automatic stop control is started. Therefore, even when the in-cylinder temperature Tc of the engine 1 that has started the automatic stop control is high, compression by supercharging is performed. Self-ignition can be prevented as much as possible.

  In the present embodiment, in-cylinder pressure detecting means (such as the engine temperature sensor 48) for detecting the in-cylinder pressure Pc of the expansion stroke cylinder (# 1) at stop and inputting it to the ECU 40 is provided. When the in-cylinder pressure Pc of the stroke cylinder (# 1) is equal to or higher than a predetermined value, the throttle opening degree Tvo of the engine 1 is controlled to be reduced. Therefore, in the present embodiment, it is possible to determine whether or not the cooling effect by the restart motor 25 is sufficient based on the in-cylinder pressure Pc of the stop expansion stroke cylinder (# 1). When the in-cylinder pressure Pc of the stop expansion stroke cylinder (# 1) is equal to or greater than a predetermined value, the throttle opening degree Tvo of the engine 1 is reduced, the filling amount is reduced, and the stop expansion stroke cylinder (# 1). It is possible to prevent compression self-ignition at

  As described above, according to the present embodiment, since the vaporization of the restart fuel injected into the intake port 6 of the stop expansion stroke cylinder (# 1) by supercharging is promoted, the stop expansion stroke at the restart is performed. As a result of improving the ignitability of the air-fuel mixture in the cylinder (# 1), there is a remarkable effect that the restart operation of the engine 1 after the automatic stop can be ensured.

  The specific configuration of the apparatus of the present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the claims. For example, the engine 1 may be restarted by driving the crankshaft by a power transmission mechanism including a pinion provided on the output shaft of the restart motor and a startering gear provided on the crankshaft. Alternatively, instead of the above embodiment in which fuel is injected immediately before the engine 1 is stopped into the cylinders that are in the exhaust stroke, the expansion stroke, and the compression stroke when the engine 1 is stopped, the exhaust stroke and the expansion stroke are stopped when the engine 1 is stopped. You may make it inject a fuel only with respect to the cylinder which becomes.

  It goes without saying that various modifications can be made within the scope of the claims of the present invention.

1 is a schematic configuration diagram of an entire vehicle control apparatus according to an embodiment of the present invention. It is the schematic of the engine employ | adopted as FIG. 3 is a time chart at the time of automatic stop control of the engine 1; It is a time chart which shows the change state of an engine speed. It is a graph which shows the relationship between the control time of the electric supercharger which concerns on this embodiment, and in-cylinder temperature. It is a graph which shows the relationship between the throttle opening which concerns on this embodiment, and a cylinder pressure. It is a flowchart of the automatic stop control in this embodiment. It is a flowchart of the automatic stop control in this embodiment. It is a flowchart of the automatic stop control in this embodiment. 10 is a timing chart based on the automatic stop control of FIGS. It is a flowchart which shows the control after an automatic stop.

Explanation of symbols

1 Engine 2 Cylinder 4 Combustion chamber 5 Crankshaft (output shaft)
6 Intake port 6a Intake valve 8 Fuel injection valve 9 Intake passage 10 Exhaust passage 12a Actuator 12 Throttle valve 14 Electric supercharger 18 Battery 19 Inverter 20 Crank angle sensor 25 Restart motor (drive motor)
27 Rotation angle sensor 28 DC / DC converter 29 Lead storage battery 30 Voltage sensor 31 Starter motor 32 Gear mechanism 40 ECU
41 Accelerator pedal 42 Accelerator sensor 43 Shift position sensor 44 Ignition switch 45 Brake pedal 46 Brake switch 47 Remaining battery sensor 48 Engine temperature sensor 48 Temperature sensor 49 Intake temperature sensor 50 Air flow sensor 51 Intake pipe negative pressure sensor N Engine speed Pc Cylinder Internal pressure Pclt Threshold value Pcs Threshold value R Reference rotation speed t Count time T10 Drive timing Tc In-cylinder temperature Tcs Threshold value Tm Operation start timing Ts Stop timing Tvo Throttle opening

Claims (5)

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 intake port of the expansion stroke cylinder at the time of stop, and ignites the expansion stroke cylinder at the time of restart of the automatically stopped engine,
A turbocharger that supercharges the intake air of the engine,
The control device for a vehicle operates the supercharger after the automatic stop condition is established prior to injecting fuel into the intake port of the expansion stroke cylinder at the time of stop. The vehicle control device according to claim 1,
In-cylinder temperature detecting means for detecting the in-cylinder temperature of the expansion stroke cylinder at the stop time and inputting it to the control means,
The control device for a vehicle, wherein the control means prohibits the operation of the supercharger when the detected in-cylinder temperature is equal to or higher than a predetermined value. The vehicle control device according to claim 2,
Provide a drive motor to drive the output shaft of the engine,
The control device for a vehicle, wherein when the operation of the supercharger is prohibited, the control means operates a drive motor prior to injecting fuel into the intake port of the expansion stroke cylinder at the time of stop. The vehicle control device according to claim 3,
The control means operates the drive motor when the automatic stop operation is started, and stops the drive motor and operates the supercharger after the detected in-cylinder temperature becomes lower than a preset value. A control apparatus for a vehicle. The vehicle control device according to claim 3 or 4,
In-cylinder pressure detection means for detecting the cylinder pressure of the expansion stroke cylinder at the time of stop and inputting it to the control means,
The vehicle control apparatus according to claim 1, wherein the control means controls the throttle opening of the engine to be reduced when the in-cylinder pressure of the expansion stroke cylinder at the stop is equal to or greater than a predetermined value.

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