JP2010163898A - Starter of internal combustion engine - Google Patents

Abstract

An internal combustion engine starter capable of shortening the restart time of an internal combustion engine is provided.
[Solution]
The starter of the internal combustion engine includes a crank angle sensor 32 that detects the rotational speed of the internal combustion engine 1 and a control unit 60 that controls fuel supply and air supply to the combustion chamber 12 by the integrated injector 20. The control unit 60 supplies air to the cylinder 10 in the expansion stroke when the amount of fuel supplied by the integrated injector 20 is zero and the rotational speed detected by the crank angle sensor 32 is zero (step S10). The integrated injector 20 is controlled so as to be supplied (step S11).
[Selection] Figure 3

Description

  The present invention relates to a starter for an internal combustion engine that restarts the internal combustion engine by supplying air and fuel to a combustion chamber of a cylinder in an expansion stroke and performing ignition.

  2. Description of the Related Art An engine starter that restarts an engine without using a starter by injecting air and fuel into a combustion chamber of a cylinder in an expansion stroke to perform ignition is known (see, for example, Patent Documents 1 to 3). ).

JP 2006-336572 A JP 2007-71037 A JP 2002-39038 A

  In the above starting device, there is a problem that it takes time until the engine is restarted because air is injected into the combustion chamber after a trigger input for restarting the internal combustion engine such as brake-off.

  The problem to be solved by the present invention is to provide a starter for an internal combustion engine that can shorten the restart time of the internal combustion engine.

  The present invention solves the above problem by supplying air to the combustion chamber of the cylinder in the expansion stroke when the fuel supply to the combustion chamber is zero and the rotation speed of the internal combustion engine is equal to or lower than the predetermined rotation speed. Resolve.

  According to the present invention, air can be supplied to the combustion chamber of the cylinder in the expansion stroke while the internal combustion engine is stopped, and the internal combustion engine can be restarted simply by performing fuel supply and ignition at the time of trigger input. The time required for restarting the internal combustion engine can be shortened.

FIG. 1 is a diagram showing an engine system in an embodiment of the present invention. FIG. 2 is a diagram showing another example of the engine system in the embodiment of the present invention. FIG. 3 is a flowchart showing the idle stop control in the first embodiment of the present invention. FIG. 4 is a graph showing the air injection amount according to the elapsed time during the idle stop in the first embodiment of the present invention. FIG. 5 is a flowchart showing the idle stop control in the second embodiment of the present invention. FIG. 6 is a graph showing a map in which piston positions are associated with air injection intervals in the second embodiment of the present invention. FIG. 7 is a graph showing the air injection amount according to the elapsed time during the idle stop in the second embodiment of the present invention. FIG. 8 is a flowchart showing the idle stop control in the third embodiment of the present invention. FIG. 9 is a graph showing a map in which piston positions are associated with predetermined pressures in the third embodiment of the present invention. FIG. 10 is a graph showing the relationship between the in-cylinder pressure and the air injection amount according to the elapsed time during the idle stop in the third embodiment of the present invention. FIG. 11 is a flowchart showing coast stop control in the fourth embodiment of the present invention. FIG. 12 is a graph showing a map in which the throttle opening degree during the coast stop and the air injection amount are associated in the fourth embodiment of the present invention. FIG. 13 is a graph showing the relationship between the rotational speed, the piston position, and the air injection amount according to the elapsed time during the coast stop in the fourth embodiment of the present invention. FIG. 14 is a flowchart showing coast stop control in the fifth embodiment of the present invention. FIG. 15 is a graph showing the relationship between the rotational speed, the in-cylinder pressure, and the air injection amount according to the elapsed time during the coast stop in the fifth embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. An internal combustion engine system common to first to fifth embodiments described later will be described first, and then each embodiment will be described.

  FIG. 1 is a diagram showing an engine system in an embodiment of the present invention, and FIG. 2 is a diagram showing another example of an engine system in an embodiment of the present invention.

  The engine 1 in the present embodiment is, for example, a 4-cylinder direct injection engine. As shown in FIG. 1, the engine 1 includes an integrated injector 20 and a spark plug 31 provided so as to face the combustion chamber 12 of each cylinder 10. FIG. 1 shows only one cylinder 10, and the number of cylinders is not particularly limited in the present invention.

  The integrated injector 20 has a function of injecting fuel into the combustion chamber 12 and a function of injecting air into the combustion chamber 12. A fuel line 22 that is a fuel supply path and an air line 27 that is an air supply path are connected to the integrated injector 20.

  A fuel tank 25 is connected to the tip of the fuel line 22 via a pressure regulator 23 and a fuel pump 24. The fuel pump 23 pumps fuel from the fuel tank 24 to the pressure regulator 23, and the pressure regulator 23 adjusts the fuel to a predetermined pressure and supplies it to the integrated injector 20. The integrated injector 20 injects the fuel directly into the combustion chamber 12.

  On the other hand, an air pump 28 is connected to the tip of the air line 27. The integrated injector 20 directly injects air pumped from the air pump 28 through the air line 27 into the combustion chamber 12.

  The integrated injector 20 is driven to open by a drive pulse signal set in the control unit 60, thereby injecting a predetermined amount of fuel or air into the combustion chamber 12. The spark plug 31 ignites the air-fuel mixture filled in the combustion chamber 12 based on the ignition signal from the control unit 60.

  In place of the integrated injector 20, as shown in FIG. 2, the engine 1 has a fuel injector 21 that injects only fuel into the combustion chamber 12, and an air injector that injects only air into the combustion chamber 12. 26 may be provided independently.

  Returning to FIG. 1, the engine 1 includes a crank angle sensor 32, a cam angle sensor 33, and an in-cylinder pressure sensor 34. The crank angle sensor 32 outputs a unit angle signal of the crank angle synchronized with the rotation of the crankshaft 15. On the other hand, the cam angle sensor 33 outputs a reference signal every time the camshaft 16 makes one rotation (that is, the crank angle corresponds to every 720 degrees). Both the crank angle sensor 32 and the cam angle sensor 33 are connected to the control unit 60. The control unit 60 detects the rotational speed of the engine 1 and the position of the piston 11 based on the unit angle signal output from the crank angle sensor 32. Further, the control unit 60 (cylinder discrimination means) discriminates the cylinder 10 in the expansion stroke based on the unit angle signal output from the crank angle sensor 32 and the reference signal output from the cam angle sensor 33. The in-cylinder pressure sensor 34 is also connected to the control unit 60, and the control unit 60 detects the pressure in the combustion chamber 12 based on the output signal of the in-cylinder pressure sensor 34.

  An air filter 41, an air flow meter 42, a throttle valve 43, and an intake manifold 46 are provided in the intake passage 40 communicating with the intake port 13 of the engine 1. The throttle valve 43 is provided with a throttle valve control device 44 that can control the opening degree of the throttle valve 43 by an actuator such as a DC motor. The control unit 60 calculates a necessary torque based on the operation amount of the accelerator pedal detected by the accelerator pedal position sensor 61 and outputs a drive signal to the throttle valve control device 44. The throttle valve control device 44 electronically controls the opening degree of the throttle valve 43 based on the drive signal from the control valve 60. The throttle valve 43 is provided with a throttle position sensor 45 that detects the opening of the throttle valve 43. The throttle position sensor 45 is connected to the control unit 60 and outputs a detection signal to the control unit 60.

  An exhaust passage 50 communicating with the exhaust port 14 of the engine 1 is provided with an exhaust purification catalyst 51 for purifying the exhaust, and a muffler 52 that silences and cools the exhaust.

  The control unit 60 is composed of a microcomputer including a CPU, a ROM, a RAM, an A / D converter, an input / output interface, and the like, to which various sensors described above are connected. The control unit 60 controls the opening degree of the throttle valve 43 via the throttle valve control device 44 according to the operating state detected based on the signals from these sensors, and drives the integrated injector 20. Control is performed to control the fuel injection amount, set the ignition timing, and ignite the spark plug 31 at the ignition timing.

  Also connected to the control unit 60 are a brake position sensor 62 for detecting the amount of depression of the brake pedal by the driver, a shift lever position sensor 63 for detecting the shift position, and an ignition switch 64 for turning on / off the ignition. Yes.

  Furthermore, the control unit 60 of the present embodiment performs control related to idle stop that is restarted after stopping the engine with a temporary stop of the vehicle, or after temporarily stopping the engine with the deceleration of the vehicle. Control relating to the coast stop to be restarted can be executed.

  Specific examples regarding the idle stop control will be described in detail in the first to third embodiments, and specific examples regarding the coast stop control will be described in detail in the fourth and fifth embodiments.

<First Embodiment>
The idle stop control in the first embodiment will be described below with reference to FIGS. FIG. 3 is a flowchart showing the idle stop control in the present embodiment, and FIG. 4 is a graph showing the air injection amount according to the elapsed time during the idle stop in the present embodiment.

  First, in step S10 of FIG. 3, the control unit 60 determines whether or not the engine 1 is in an idle stop state. In this embodiment, (i) the amount of fuel injected into the combustion chamber 12 is zero, (ii) the number of revolutions of the engine 1 is zero, (iii) the ignition switch is on, and (iv) the shift position is When it is in the D range and (v) the amount of depression of the brake pedal by the driver is 100%, it is determined that the engine 1 is in the idle stop state. Therefore, the control unit 60 is based on the fuel injection amount set by the control unit 60 and the output signals from the crank angle sensor 32, the ignition switch 64, the shift lever position sensor 63, and the brake position sensor 62. Determine whether the condition is met. Note that the determination element as to whether or not the engine 1 is in the idling stop state is not limited to the above, and the speed of the vehicle, the temperature of the cooling water, the operation amount of the accelerator pedal, and the like may be employed.

  If it is determined in step S10 that engine 1 is not in the idle stop state (NO in step S10), this flow is terminated.

  On the other hand, when it is determined in step S10 that engine 1 is in the idle stop state (YES in step S10), in step S11, control unit 60 causes the integral injector to inject air into combustion chamber 12. 20 is controlled. The integrated injector 20 injects a certain amount of air into the combustion chamber 12 based on the drive signal from the control unit 60 as shown in FIG.

  Next, in step S12 of FIG. 3, the control unit 60 determines whether an idle stop cancellation condition is satisfied. In the present embodiment, when the driver removes his / her foot from the brake pedal, it is determined that the condition for releasing the idle stop is satisfied. Therefore, the control unit 60 determines whether the depression amount of the brake pedal has become 0% based on the output signal from the brake position sensor 62. Note that the determination element for determining whether or not the idle stop cancellation condition is satisfied is not limited to the above, and an accelerator pedal operation amount or the like may be employed.

  In step S12, unless the idle stop cancellation condition is satisfied (NO in step S12), the integrated injector 20 continues to inject a certain amount of air into the combustion chamber 12, as shown in FIG.

  On the other hand, when the idle stop cancellation condition is satisfied in step S12 (YES in step S12), the injection of air by the integrated injector 20 is stopped and this flow is ended.

  When this flow ends, the control unit 60 performs control to restart the engine 1. That is, the control unit 60 detects the cylinder 10 in the expansion stroke based on the output signals from the crank angle sensor 32 and the cam angle sensor 33 when the idle stop is executed (when the engine is stopped). When the idle stop cancellation condition is satisfied, the control unit 60 controls the integrated injector 20 and the spark plug 31 so as to inject fuel into the combustion chamber 12 of the cylinder 10 and ignite the generated air-fuel mixture. .

  As described above, in this embodiment, the engine 1 can be restarted simply by injecting air into the cylinder 10 that is in the expansion stroke during idle stop and performing fuel injection and ignition when the idle stop is released. The time required for restarting the engine 1 can be shortened.

<Second Embodiment>
Hereinafter, idle stop control according to the second embodiment will be described with reference to FIGS. The idle stop control in the second embodiment is different from the first embodiment in that air is injected at regular intervals during the idle stop.

  FIG. 5 is a flowchart showing the idle stop control in the second embodiment of the present invention, FIG. 6 is a graph showing a map in which the piston position and the air injection interval are associated with each other in the second embodiment of the present invention, and FIG. It is a graph which shows the air injection quantity according to the elapsed time during the idle stop in 2nd Embodiment of this.

  In the present embodiment, first, in step S20 of FIG. 5, the control unit 60 determines whether or not the engine 1 is in an idle stop state. In the present embodiment, as in the first embodiment, whether or not the engine 1 is in the idle stop state is determined based on the fuel injection amount, the engine speed, the ignition switch, the shift position, and the brake pedal depression amount. to decide.

  If it is determined in step S20 that engine 1 is not in the idle stop state (NO in step S20), this flow is terminated. On the other hand, when it is determined in step S20 that engine 1 is in the idle stop state (YES in step S20), the process proceeds to step S21.

Next, in step S21, the control unit 60 detects the position of the piston 11 in the cylinder 10 in the expansion stroke based on the output signal from the crank angle sensor 32. The discrimination of the cylinder 10 in the expansion stroke is detected by the control unit 60 at the time of idling stop based on the output signals from the crank angle sensor 32 and the cam angle sensor 33.

  Next, the control unit 60 reads the air injection interval t1 corresponding to the position of the piston 11 with reference to the map shown in FIG. The map shown in FIG. 6 is stored in advance in the control unit 60. As shown in FIG. 6, the map referred to by the control unit 60 in step S <b> 21 is set so that the injection interval t <b> 1 becomes shorter as the position of the piston 11 is closer to the top dead center.

  Generally, the closer the position of the piston 11 is to the top dead center, the smaller the amount of air in the combustion chamber 12. Therefore, in the present embodiment, the amount of air necessary for restarting the engine 1 is ensured by setting the air injection interval t1 to be shorter as the position of the piston 11 is closer to the top dead center.

  Next, in step S22, the first air injection by the integrated injector 20 is performed. That is, the control unit 60 controls the integrated injector 20 so as to inject a certain amount of air into the combustion chamber 12, and the integrated injector 20 sends a certain amount of air into the combustion chamber 12 based on the drive signal. To spray. When the injection of a fixed amount of air by the integrated injector 20 is completed, the control unit 60 starts measuring the elapsed time t from the completion of the injection (step S23 in FIG. 5).

  Next, in step S24, the control unit 60 compares the elapsed time t at which time measurement was started in step S23 with the injection interval t1 read in step S21.

  If the elapsed time t is equal to or shorter than the injection time t1 in the comparison in step S24 (NO in step S24), the process waits until the elapsed time t becomes larger than the injection interval t1.

  If the elapsed time t is longer than the injection time t1 in the comparison in step S24 (YES in step S24), the second and subsequent air injections by the integrated injector 20 are performed in step S25. That is, the control unit 60 controls the integrated injector 20 so as to inject air into the combustion chamber 12. The integrated injector 20 injects a certain amount of air into the combustion chamber 12 based on a drive signal from the control unit 60.

  Next, in step S26 of FIG. 5, the control unit 60 determines whether or not an idle stop cancellation condition is satisfied. In the present embodiment, as in the first embodiment, it is determined whether an idle stop cancellation condition is satisfied based on the amount of depression of the brake pedal.

  In step S26, unless the condition for releasing the idle stop is satisfied (NO in step S26), steps S23 to S25 in FIG. 5 are repeated, and the integrated injector 20 continues the idle stop as shown in FIG. During this time, a certain amount of air is injected into the combustion chamber 12 at every injection interval t1. The elapsed time t is reset when returning from step S26 to step S23.

  On the other hand, when the idle stop cancellation condition is satisfied in step S26 (YES in step S26), this flow ends. When this flow ends, the control unit 60 performs control to restart the engine 1 as in the first embodiment.

  As described above, in the present embodiment, air is injected into the combustion chamber 12 of the cylinder 10 in the expansion stroke during the idle stop, and the engine 1 is restarted simply by performing fuel injection and ignition when the idle stop is released. Therefore, the time required for restarting the engine 1 can be shortened.

  Further, in the present embodiment, since the air injection interval t1 is changed according to the position of the piston 11, the amount of air necessary for restarting the engine 1 can be appropriately ensured.

<Third Embodiment>
Hereinafter, idle stop control according to the third embodiment will be described with reference to FIGS. The idle stop control in the third embodiment is different from the first and second embodiments in that air is injected based on the in-cylinder pressure.

  FIG. 8 is a flowchart showing the idle stop control in the third embodiment of the present invention, FIG. 9 is a graph showing a map in which the piston position is associated with the predetermined pressure in the third embodiment of the present invention, and FIG. It is a graph which shows the relationship between the cylinder pressure according to the elapsed time during the idle stop in 3 embodiment, and an air injection quantity.

  In the present embodiment, first, in step S30 of FIG. 8, the control unit 60 determines whether or not the engine 1 is in an idle stop state. In the present embodiment, as in the first embodiment and the second embodiment, the engine 1 enters the idle stop state based on the fuel injection amount, the engine speed, the ignition switch, the shift position, and the brake pedal depression amount. Judge whether there is.

  If it is determined in step S30 that engine 1 is not in the idling stop state (NO in step S30), this flow ends.

  On the other hand, when it is determined in step S30 that engine 1 is in the idle stop state (YES in step S30), in step S31, based on the output signal from crank angle sensor 32, in cylinder 10 in the expansion stroke. The position of the piston 11 is detected. The discrimination of the cylinder 10 in the expansion stroke is detected by the control unit 60 at the time of idling stop based on the output signals from the crank angle sensor 32 and the cam angle sensor 33.

  Next, the control unit 60 reads a predetermined pressure P1 in the combustion chamber 12 corresponding to the position of the piston 11 with reference to the map shown in FIG. The map shown in FIG. 9 is stored in advance in the control unit 60. As shown in FIG. 9, the map referred to by the control unit 60 in step S31 is set such that the predetermined pressure P1 increases as the position of the piston 11 approaches the top dead center.

  In general, the closer the position of the piston 11 is to the top dead center, the smaller the volume in the combustion chamber 12 is. Therefore, in the present embodiment, the amount of air necessary for restarting the engine 1 is secured by setting the pressure in the combustion chamber 12 higher as the position of the piston 11 is closer to top dead center.

  Next, in step S32, the control unit 60 detects the cylinder pressure P in the combustion chamber 12 based on the output signal from the cylinder pressure sensor 34, and compares this cylinder pressure P with the predetermined pressure P1 read in step S31. To do.

  If the in-cylinder pressure P is larger than the predetermined pressure P1 in the comparison in step S32 (P> P1) (YES in step S32), the process waits until the in-cylinder pressure P becomes equal to or lower than the predetermined pressure P1.

  On the other hand, if the in-cylinder pressure P is equal to or lower than the predetermined pressure P1 (P ≦ P1) in the comparison in step S32 (NO in step S32), the control unit 60 injects air into the combustion chamber 12 in step S33. Thus, the integrated injector 20 is controlled. The integrated injector 20 injects a certain amount of air into the combustion chamber 12 based on a drive signal from the control unit 60.

  Next, in step S34 of FIG. 8, the control unit 60 determines whether or not an idle stop cancellation condition is satisfied. In the present embodiment, as in the first and second embodiments, it is determined whether an idle switch release condition is satisfied based on the depression amount of the brake pedal.

  In step S34, unless the idle stop cancellation condition is satisfied (NO in step S34), steps S32 to S33 in FIG. 8 are repeated, and the integrated injector 20 continues the idle stop as shown in FIG. During this time, every time the in-cylinder pressure P becomes equal to or lower than the predetermined pressure P1, a certain amount of air is repeatedly injected into the combustion chamber 12.

  On the other hand, when the idle stop cancellation condition is satisfied in step S34 (YES in step S34), this flow ends. When this flow ends, the control unit 60 performs control to restart the engine 1 as in the first and second embodiments.

  As described above, in this embodiment, the engine 1 can be restarted simply by injecting air into the cylinder 10 that is in the expansion stroke during idle stop and performing fuel injection and ignition when the idle stop is released. The time required for restarting the engine 1 can be shortened.

  Moreover, in this embodiment, since the predetermined pressure P1 is changed according to the position of the piston 11, the amount of air necessary for restarting the engine 1 can be ensured appropriately.

<Fourth embodiment>
Below, the coast stop control in 4th Embodiment is demonstrated, referring FIG. 11 thru | or FIG.

  FIG. 11 is a flowchart showing coast stop control according to the fourth embodiment of the present invention. FIG. 12 is a graph showing a map in which the throttle opening degree and the air injection amount are associated with each other during coast stop according to the fourth embodiment of the present invention. 13 is a graph showing the relationship between the rotational speed, the piston position, and the air injection amount according to the elapsed time during the coast stop in the fourth embodiment of the present invention.

  In the present embodiment, first, in step S40 of FIG. 11, the control unit 60 determines whether or not the engine 1 is in a coast stop state. In this embodiment, (i) the amount of fuel injected into the combustion chamber 12 is zero, (ii) the rotational speed of the engine 1 is greater than zero, (iii) the shift position is in the D range, and (iv) When the depression amount of the brake pedal by the driver is 100%, it is determined that the engine 1 is in the coast stop state. Therefore, the control unit 60 satisfies the above conditions based on the fuel injection amount set by the control unit 60 and the output signals from the crank angle sensor 32, the shift lever position sensor 63, and the brake position sensor 62. Determine whether. Note that the determination element as to whether or not the engine 1 is in the coast stop state is not limited to the above, and an accelerator pedal operation amount or the like may be employed.

  If it is determined in step S40 that engine 1 is not in the coast stop state (NO in step S40), this flow ends.

  On the other hand, when it is determined in step S10 that engine 1 is in the coast stop state (YES in step S40), in step S41, control unit 60 determines the engine 1 based on the output signal from crank angle sensor 32. The rotational speed RPM is detected, and the rotational speed RPM is compared with a predetermined rotational speed RPM1. The predetermined rotational speed RPM1 is not particularly limited, but is, for example, about 1000 [rpm] corresponding to the fuel cut recovery rotational speed set for a general vehicle. Incidentally, the fuel cut recovery rotational speed is not set for the vehicle having the coast stop control.

  If the rotation speed RPM is equal to or higher than the predetermined rotation speed RPM1 (RPM ≧ RPM1) in the comparison in step S41 (NO in step S41), the process returns to step S40. On the other hand, if the rotation speed RPM is smaller than the predetermined rotation speed RPM1 (RPM <RPM1) in the comparison in step S41 (YES in step S41), the process proceeds to step S42.

  Next, in step S42, the control unit 60 detects the position CA of the piston 11 in the cylinder 10 in the expansion stroke based on the output signal from the crank angle sensor 32.

  The position of the piston 11 in the cylinder 10 in the expansion stroke is expressed by, for example, a crank angle [deg] from the top dead center (TCD) in the expansion stroke. Further, the cylinder 10 in the expansion stroke is determined by the control unit 60 based on the output signals from the crank angle sensor 32 and the cam angle sensor 33 as in the first to third embodiments. However, the cylinder 10 in the expansion stroke does not change during the idling stop, but the cylinder 10 in the expansion stroke sequentially changes because the engine 1 continues to rotate during the coast stop. Therefore, in the present embodiment, unlike the first to third embodiments, the control unit 60 detects and updates the cylinder 10 in the expansion stroke in real time during the coast stop.

  Next, the control unit 60 compares the position CA of the piston 11 in the cylinder 10 in the expansion stroke with a predetermined piston position CA1. The predetermined piston position CA1 is, for example, a piston position at which the pressure in the combustion chamber 12 can be injected by the integrated injector 20.

  In the comparison of step S42, when the piston position CA is located on the top dead center side with respect to the predetermined piston position CA1 (CA ≦ CA1) (NO in step S42), the process returns to step S41.

  On the other hand, in the comparison in step S42, when the piston position CA is located on the bottom dead center side with respect to the predetermined piston position CA1 (CA> CA1) (YES in step S42), the process proceeds to step S43. Due to the presence of such step S42, it is possible to avoid a situation in which the in-cylinder pressure in the combustion chamber 12 is too high and air cannot be injected by the integrated injector 20.

  Next, in step S43, the control unit 60 detects the opening degree of the throttle valve 43 based on the output signal from the throttle position sensor 45. Next, the control unit reads the air injection amount corresponding to the opening degree of the throttle valve 43 with reference to the map shown in FIG. The map shown in FIG. 12 is stored in the control unit 60 in advance. As shown in FIG. 12, the map referred to by the control unit 60 in step S43 is set so that the air injection amount increases as the opening of the throttle valve 43 is closed.

  In order to prevent the rotation from returning due to the reaction of the piston in the compression stroke when the engine is stopped, the throttle valve 43 may be closed to reduce the air supply amount. On the other hand, in the present embodiment, even when the throttle valve 43 is closed in order to prevent such swinging back, the air injection amount is changed according to the opening of the throttle valve 43. An amount of air necessary for restarting can be secured.

  Next, in step S44, the control unit 60 controls the integrated injector 20 so as to inject the amount of air set in step S43 into the combustion chamber 12. The integrated injector 20 injects the amount of air set in step S43 into the combustion chamber 12 based on the drive signal from the control unit 60.

  Next, in step S45 of FIG. 11, the control unit 60 determines whether a coast stop cancellation condition is satisfied. In the present embodiment, it is determined that the coast stop cancellation condition is satisfied when the driver removes his / her foot from the brake pedal. Therefore, the control unit 60 determines whether or not the amount of depression of the brake pedal has become 0% based on the output signal from the brake position sensor 62. Note that the determination element for determining whether or not the coast stop cancellation condition is satisfied is not limited to the above, and an accelerator pedal operation amount or the like may be employed.

  In step S45, unless the coast stop cancellation condition is satisfied (NO in step S45), steps S42 to S44 of the flowchart shown in FIG. 11 are repeated. That is, as shown in FIG. 13, while the coast stop continues, the integrated injector 20 has the engine 1 whose RPM RPM is smaller than the predetermined RPM RPM1 and whose piston position CA is higher than the predetermined piston position CA1. Each time it is located on the bottom dead center side, the injection of the amount of air set in step S43 into the combustion chamber 12 is repeated.

  On the other hand, when the coast stop cancellation condition is satisfied in step S45 (YES in step S45), this flow ends. When this flow ends, the control unit 60 performs control to restart the engine 1 as in the first to third embodiments.

  As described above, in the present embodiment, the engine 1 can be restarted simply by injecting air into the cylinder 10 in the expansion stroke during the coast stop and performing fuel injection and ignition when the coast stop is released. The time required for restarting the engine 1 can be shortened.

  In the present embodiment, air is injected into the combustion chamber 12 by the integrated injector 20 when the position of the piston 11 is more than a predetermined distance from the top dead center. Therefore, it is possible to avoid a situation in which the in-cylinder pressure in the combustion chamber 12 is too high and air cannot be injected by the integrated injector 20.

  Furthermore, in this embodiment, since the air injection amount by the integrated injector 20 is changed according to the opening degree of the throttle valve 43, even when the throttle valve 43 is closed to prevent swingback, the engine 1 An amount of air necessary for restarting can be secured.

<Fifth Embodiment>
Below, the coast stop control in 5th Embodiment is demonstrated, referring FIG.14 and FIG.15.

  FIG. 14 is a flowchart showing coast stop control in the fifth embodiment of the present invention, and FIG. 15 shows the relationship among the rotational speed, in-cylinder pressure and air injection amount according to the elapsed time during coast stop in the fifth embodiment of the present invention. It is a graph to show.

  In the present embodiment, first, in step S50 of FIG. 14, the control unit 60 determines whether or not the engine 1 is in a coast stop state. In the present embodiment, as in the fourth embodiment, it is determined whether or not the engine 1 is in the coast stop state based on the fuel injection amount, the shift position, and the depression amount of the brake pedal.

  If it is determined in step S50 that engine 1 is not in the coast stop state (NO in step S50), this flow ends.

  On the other hand, when it is determined in step S50 that engine 1 is in the coast stop state (YES in step S50), in step S51, control unit 60 determines the engine 1 based on the output signal from crank angle sensor 32. The rotational speed RPM is detected, and the rotational speed RPM is compared with a predetermined rotational speed RPM1. Similar to the fourth embodiment, the predetermined rotational speed RPM1 is not particularly limited, but is, for example, about 1000 [rpm] corresponding to the fuel cut recovery rotational speed set for a general vehicle. Incidentally, the fuel cut recovery rotational speed is not set for the vehicle having the coast stop control.

  When the rotation speed RPM is equal to or higher than the predetermined rotation speed RPM1 (RPM ≧ RPM1) in the comparison in step S51 (NO in step S51), the process returns to step S50. On the other hand, when the rotation speed RPM is smaller than the predetermined rotation speed RPM1 (RPM <RPM1) in the comparison in step S51 (YES in step S51), the process proceeds to step S52.

  Next, in step S52, the control unit 60 detects the in-cylinder pressure P in the combustion chamber 12 in the cylinder 10 in the expansion stroke based on the output signal from the in-cylinder pressure sensor 34. As in the fourth embodiment, the control unit 60 detects and updates the cylinder 10 in the expansion stroke in real time based on the output signals from the crank angle sensor 32 and the cam angle sensor 33.

  Next, the control unit 60 compares the in-cylinder pressure P in the combustion chamber 12 of the cylinder 10 in the expansion stroke with a predetermined pressure P2. The predetermined pressure P2 is, for example, an in-cylinder pressure at which air can be injected into the combustion chamber 12 by the integrated injector 20.

  If the in-cylinder pressure P is greater than the predetermined pressure P2 (P> P2) in step S52 (NO in step S52), the process returns to step S51.

  On the other hand, if the in-cylinder pressure P is equal to or lower than the predetermined pressure P2 (P ≦ P2) in the comparison in step S52 (YES in step S52), the process proceeds to step S53. The presence of such step S52 can avoid a situation where the in-cylinder pressure in the combustion chamber 12 is too high and air cannot be injected by the integrated injector 20.

  Next, in step S53, the control unit 60 detects the opening degree of the throttle valve 43 in the same manner as in step S43 in the fourth embodiment, and refers to the map shown in FIG. Read the air injection amount. Thereby, even when the throttle valve 43 is closed to prevent swinging back, it is possible to secure an amount of air necessary for restarting the engine 1.

  Next, in step S54, the control unit 60 controls the integrated injector 20 so as to inject the amount of air set in step S53 into the combustion chamber 12. The integrated injector 20 injects the amount of air set in step S54 into the combustion chamber 12 based on the drive signal from the control unit 60.

  Next, in step S55 in FIG. 14, the control unit 60 determines whether or not a coast stop cancellation condition is satisfied. In the present embodiment, as in the fourth embodiment, it is determined whether a coast stop release condition is satisfied based on the amount of depression of the brake pedal.

  In step S55, unless the coast stop cancellation condition is satisfied (NO in step S55), steps S52 to S54 in the flowchart shown in FIG. 14 are repeated. That is, as shown in FIG. 15, while the coast stop is continued, the integrated injector 20 is configured such that the rotational speed RPM of the engine 1 is smaller than the predetermined rotational speed RPM1 and the in-cylinder pressure P is equal to or lower than the predetermined pressure P2. Each time, the injection of the amount of air set in step S53 into the combustion chamber 12 is repeated.

  On the other hand, when the coast stop cancellation condition is satisfied in step S55 (YES in step S55), the present flow is ended. When this flow is finished, the control unit 60 performs control to restart the engine 1 as in the first to fourth embodiments.

  As described above, in the present embodiment, the engine 1 can be restarted simply by injecting air into the cylinder 10 in the expansion stroke during the coast stop and performing fuel injection and ignition when the coast stop is released. The time required for restarting the engine 1 can be shortened.

  Further, in this embodiment, when the in-cylinder pressure becomes equal to or lower than a predetermined pressure, air is injected into the combustion chamber 12 by the integrated injector 20. Therefore, it is possible to avoid a situation in which the in-cylinder pressure in the combustion chamber 12 is too high and air cannot be injected by the integrated injector 20.

  Furthermore, in this embodiment, since the air injection amount by the integrated injector 20 is changed according to the opening degree of the throttle valve 43, even when the throttle valve 43 is closed to prevent swingback, the engine 1 An amount of air necessary for restarting can be secured.

  The crank angle sensor 32 in the embodiment described above corresponds to an example of the rotational speed detection means and the position detection means of the present invention. The rotation speed detection means in the present invention only needs to be able to detect the idling stop state and the coast stop state as a result, and therefore includes means capable of indirectly detecting the rotation speed, such as a vehicle speed sensor. It is.

  The integrated injector 20 in the embodiment described above corresponds to an example of the fuel supply means and the air supply means of the present invention, and the control unit 60 in the embodiment corresponds to an example of the control means of the present invention. The sensor 34 corresponds to an example of the pressure detection means of the present invention, and the throttle position sensor 45 in the embodiment corresponds to an example of the opening degree detection means of the present invention.

  The embodiment described above is described for facilitating the understanding of the present invention, and is not described for limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

DESCRIPTION OF SYMBOLS 1 ... Engine 10 ... Cylinder 11 ... Piston 12 ... Combustion chamber 20 ... Integrated injector 22 ... Fuel line 27 ... Air line 31 ... Spark plug 32 ... Crank angle sensor 33 ... Cam angle sensor 34 ... In-cylinder pressure sensor 40 ... Intake passage 43 ... Throttle valve 44 ... Throttle valve control device 45 ... Throttle position sensor 60 ... Control unit 61 ... Accelerator position sensor 62 ... Brake position sensor 63 ... Shift lever position sensor 64 ... Ignition switch

Claims (10)

An internal combustion engine starter for restarting an internal combustion engine by supplying air and fuel to a combustion chamber of a cylinder in an expansion stroke and performing ignition,
A rotational speed detection means for detecting the rotational speed of the internal combustion engine;
Control means for controlling fuel supply to the combustion chamber by a fuel supply means, and air supply to the combustion chamber by an air supply means,
When the fuel supply amount by the fuel supply means is zero and the rotational speed detected by the rotational speed detection means is less than or equal to a predetermined rotational speed, the control means is provided in the combustion chamber of the cylinder in the expansion stroke. A starter for an internal combustion engine, wherein the air supply means is controlled to supply air. An internal combustion engine starter according to claim 1,
The control means controls the air supply means so as to supply air to a combustion chamber of a cylinder in an expansion stroke when the rotation speed detected by the rotation speed detection means is zero. A starting device for an internal combustion engine. An internal combustion engine starter according to claim 2,
The internal combustion engine starter according to claim 1, wherein the control means controls the air supply means so as to supply air at predetermined intervals to a combustion chamber of a cylinder in an expansion stroke. An internal combustion engine starter according to claim 3,
It further comprises position detecting means for detecting the position of the piston in the cylinder in the expansion stroke,
The starter for an internal combustion engine, wherein the control means changes the predetermined interval according to the position of the piston detected by the position detection means. An internal combustion engine starter according to claim 2,
Pressure detecting means for detecting the in-cylinder pressure of the cylinder in the expansion stroke;
The control means controls the air supply means so as to supply air to a combustion chamber of a cylinder in an expansion stroke when the in-cylinder pressure detected by the pressure detection means becomes a predetermined pressure or less. An internal combustion engine starter. An internal combustion engine starter according to claim 5,
It further comprises position detecting means for detecting the position of the piston in the cylinder in the expansion stroke,
The internal combustion engine starter according to claim 1, wherein the control means changes the predetermined pressure in accordance with the position of the piston detected by the position detection means. An internal combustion engine starter according to claim 1,
The control means controls the air supply means so as to supply air to a combustion chamber of a cylinder in an expansion stroke when the rotation speed detected by the rotation speed detection means is larger than zero. A starting device for an internal combustion engine. An internal combustion engine starter according to claim 7,
It further comprises position detecting means for detecting the position of the piston in the cylinder in the expansion stroke,
The control means controls the air supply means to supply air to a combustion chamber of a cylinder in an expansion stroke when the position of the piston detected by the position detection means is more than a predetermined distance from the top dead center. An internal combustion engine starter that controls the engine. An internal combustion engine starter according to claim 7,
It further comprises opening detection means for detecting the opening of the throttle valve,
The control means changes the amount of air supplied by the air supply means to a combustion chamber of a cylinder in an expansion stroke according to the opening degree of the throttle valve detected by the opening degree detection means. A starting device for an internal combustion engine. An internal combustion engine starter according to claim 7,
Pressure detecting means for detecting the in-cylinder pressure of the cylinder in the expansion stroke;
The control means controls the air supply means so as to inject air into a combustion chamber of a cylinder in an expansion stroke when the in-cylinder pressure detected by the pressure detection means becomes a predetermined pressure or less. An internal combustion engine starter.

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