JP2006336572A - Starter of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a starter of an internal combustion engine capable of realizing speedy and silent start by direct start in a wide scope. <P>SOLUTION: Ignition is performed after supplying compressed air and fuel into a combustion chamber 2 in a cylinder in an expansion stroke while the engine 1 stops, and compressed air is supplied into the combustion chamber 2 in the cylinder in a compression stroke while the engine stops when a stop position of a piston 16 in the cylinder is less than a predetermined crank angle, namely, in the vicinity of top dead center for ignition. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an internal combustion engine starter, and more particularly to a technique for starting an internal combustion engine by causing combustion in a combustion chamber.

Conventionally, as a starting method of an internal combustion engine (hereinafter, also referred to as an engine), there is a so-called direct start technique in which combustion is caused in a combustion chamber of an expansion stroke cylinder to use the combustion energy as starting power.
However, the startability of the direct start depends on the stop position of the piston of the cylinder in the expansion stroke while the engine is stopped, that is, the amount of air in the combustion chamber. For example, the combustion in the expansion stroke cylinder in a state where the air amount is small Even if this occurs, it is difficult to obtain expansion work that is commensurate with the start of the engine.

Thus, the engine start by direct start has a limited range.
In view of this, a technique has been developed in which the starter is operated supplementarily when the engine is not completely started due to combustion in the expansion stroke cylinder (see Patent Document 1).
Japanese Patent Laid-Open No. 2002-4985

However, as disclosed in the above-mentioned Patent Document 1, when the start state by the direct start is incomplete, it is possible to ensure the start by operating the motor and adding the cranking. It is not something to secure.
That is, the technique disclosed in Patent Document 1 has a problem that it is not possible to make full use of advantages such as quick start by direct start and quietness.

  In addition, since direct start usually causes combustion in the expansion stroke cylinder, it is mainly applied to an in-cylinder injection type engine that can supply fuel into the combustion chamber of the expansion stroke cylinder even when the engine is stopped. Therefore, it has been difficult to apply to the so-called MPI engine of the intake pipe injection type in which the injector faces the intake port and the supply of fuel into the combustion chamber is limited to the intake stroke.

  The present invention has been made to solve such problems, and an object of the present invention is to provide a starter for an internal combustion engine that can perform a quick and silent start by a direct start in a wider range. It is in.

  In order to achieve the above object, in the internal combustion engine starter according to claim 1, an internal combustion engine having a plurality of cylinders, cylinder discrimination means for discriminating each stroke of the plurality of cylinders, and each of the plurality of cylinders Piston position detecting means for detecting a piston position, fuel supply means for supplying fuel to the combustion chambers of the plurality of cylinders, compressed air supply means for directly supplying compressed air to the combustion chambers of the plurality of cylinders, An ignition unit that performs ignition in each combustion chamber of the plurality of cylinders, and a cylinder that is in an expansion stroke and a cylinder that is in a compression stroke while the internal combustion engine is stopped, which is determined by the cylinder determination unit by the fuel supply unit In the combustion chamber of the engine, fuel is supplied or supplied while the internal combustion engine is stopped, and the compressed air supply means causes the ignition hand in the cylinder in the expansion stroke while the internal combustion engine is stopped. The piston position detected by the piston position detecting means of the cylinder that was in the compression stroke while supplying the compressed air into the combustion chamber of the cylinder in the expansion stroke before ignition by Before the ignition by the ignition means in the cylinder that was in the compression stroke, compressed air is supplied into the combustion chamber of the cylinder that was in the compression stroke, and the ignition means In order to start the internal combustion engine, ignition is performed in the cylinder in the expansion stroke while the internal combustion engine is stopped, and the cylinder in the compression stroke is shifted to the expansion stroke while the internal combustion engine is stopped. And a control means for controlling the cylinder to perform ignition.

  That is, the cylinders in the expansion stroke and the cylinders in the compression stroke are detected while the internal combustion engine is stopped, and fuel and compressed air are supplied to the cylinders in the expansion stroke before the internal combustion engine is started. Fuel is supplied to the cylinder. Then, ignition is performed in the cylinder in the expansion stroke to cause combustion to start the internal combustion engine, and with respect to the cylinder in the compression stroke, the piston position when the internal combustion engine is stopped is at the top dead center side than the predetermined position. In such a case, the compressed air is supplied, and then the expansion stroke is started and ignition is performed.

According to a second aspect of the present invention, there is provided a starting device for an internal combustion engine according to the first aspect, wherein the compressed air supply means is responsive to a piston position detected by the piston position detection means of a cylinder that is in a compression stroke while the internal combustion engine is stopped. Then, the amount of compressed air to the cylinder in the compression stroke is changed.
That is, the amount of compressed air supplied to the cylinder in the compression stroke is changed according to the piston stop position.

According to a third aspect of the present invention, there is provided a starter for an internal combustion engine according to the first or second aspect, wherein the cylinder discrimination means discriminates a cylinder that is in the intake stroke while the internal combustion engine is stopped, and the cylinder in the intake stroke also has a combustion chamber. Fuel is supplied or supplied while the internal combustion engine is stopped.
That is, fuel is supplied to the combustion chamber of the cylinder in the intake stroke while the internal combustion engine is stopped before the internal combustion engine is started.

  According to a fourth aspect of the present invention, there is provided a starting device for an internal combustion engine according to the first or second aspect, wherein the fuel supply means is provided so as to face each intake port of the plurality of cylinders, and the control means is configured to perform the ignition by the fuel supply means. By supplying fuel into the combustion chamber during the intake stroke from when the ignition by the means is stopped until the internal combustion engine is stopped, the expansion stroke is determined while the internal combustion engine is stopped, which is determined by the cylinder determining means. Fuel is supplied to a combustion chamber of a certain cylinder and a cylinder in the compression stroke.

  That is, when the internal combustion engine has a fuel supply means facing the intake port, that is, a so-called MPI engine in which fuel supply to the combustion chamber is limited only during the intake stroke, it is in the expansion stroke cylinder while the internal combustion engine is stopped. Since fuel is supplied into the combustion chambers of the cylinders and the cylinders in the compression stroke, ignition is stopped when the internal combustion engine is stopped, and fuel is supplied during the intake stroke until the internal combustion engine stops.

  According to the starter for an internal combustion engine of the present invention using the above means, in the direct start for starting the internal combustion engine by causing combustion in the cylinder in the expansion stroke, the compression stroke is started before the internal combustion engine is started. Fuel is supplied in advance to a cylinder, and when the piston position of the cylinder is on the top dead center side from a predetermined position, ignition is performed after supplying compressed air into the combustion chamber and increasing the air amount. As a result, combustion of the cylinder can be favorably caused, and startability by direct start can be improved.

As described above, the internal combustion engine starter according to the present invention can be started well even in the engine stop range, which is difficult to start by direct start. A quiet start can be made possible.
According to the internal combustion engine starter of the second aspect, the compressed air amount is changed and supplied to the cylinder in the compression stroke before starting the internal combustion engine in accordance with the piston position of the cylinder. As a result, combustion of the cylinder can be satisfactorily generated, reaction force during compression of the cylinder can be suppressed, and startability by direct start can be improved.

According to the internal combustion engine starter of the third aspect of the present invention, fuel is supplied in advance to the combustion chamber of the cylinder in the intake stroke while the internal combustion engine is stopped, so that sufficient vaporization is achieved until the first ignition of the cylinder. Since the time can be ensured, the cylinder is also combusted satisfactorily, and the startability of the internal combustion engine can be further improved.
According to the internal combustion engine starter of the present invention, even in the MPI engine, the fuel is supplied during the intake stroke until the ignition is stopped and the internal combustion engine is stopped. In addition, fuel can be supplied in advance into the combustion chamber of the compression stroke cylinder, a sufficient vaporization time can be secured until ignition of each cylinder, and startability by direct start can be improved.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
First, a first embodiment will be described. Referring to FIG. 1, there is shown a schematic configuration diagram of a starting device for an internal combustion engine according to a first embodiment of the present invention.
The engine 1 (internal combustion engine) is composed of four cylinders #A, #B, #C, and #D arranged in series, and an in-cylinder injection type four-cycle in-line four-cylinder that explodes at equal intervals of 180 ° CA. FIG. 1 shows a longitudinal section of one of the cylinder engines. In addition, illustration and description are abbreviate | omitted as what has the same structure also about another cylinder.

  As shown in FIG. 1, an ignition plug 4 (ignition means) for performing ignition and an air assist injector 6 (fuel injection means) capable of directly injecting fuel and compressed air into the combustion chamber 2 are provided in the combustion chamber 2 of the engine 1. , Compressed air supply means). The air assist injector 6 is a known one, and the description of its configuration is omitted here. The air assist injector 6 is connected to a fuel line 6a that is a fuel supply path and an air line 6b that is an air supply path.

  Further, the combustion chamber 2 communicates with an intake port 8 that extends substantially in the vertical direction of the engine 1 and an exhaust port 10 that extends substantially in the width direction of the engine 1. The intake port 8 and the exhaust port 10 are respectively provided with an intake valve 12 and an exhaust valve 14 for communicating and blocking between the combustion chamber 2, the intake port 8, and the exhaust port 10. Further, a piston 16 that slides up and down is provided in the cylinder, and the top surface of the piston 16 in which the recess is formed forms the lower surface of the combustion chamber 2.

The piston 16 is connected to the crankshaft 20 via a connecting rod 18. A flywheel 22 is provided at one end of the crankshaft 20.
The engine 1 includes a crank angle sensor 24 (piston position detecting means) for detecting the rotation angle of the crankshaft 20, that is, a crank angle, and a camshaft (not shown) that opens and closes the intake valve 12 and the exhaust valve 14 with cams. ), That is, a cam angle sensor 26 (cylinder discrimination means) for detecting the cam angle.

Various devices such as the spark plug 4, the air assist injector 6, the crank angle sensor 24, and the cam angle sensor 26 and various sensors are electrically connected to an ECU (electronic control unit) 30. The ECU 30 includes various sensors. It controls the operation of various devices based on information from each category.
The ECU 30 is electrically connected to the ignition switch 32. Thus, when the driver performs an ON / OFF switching operation of the ignition switch 32, a start / stop signal for the engine 1 is transmitted to the ECU 30 accordingly.

The operation of the internal combustion engine starter according to the first embodiment of the present invention constructed as above will be described below.
Referring to FIGS. 2 to 5, FIG. 2 is a flowchart showing a start control routine of the engine 1 executed by the ECU 30 in the first embodiment of the present invention, and FIG. 3 is an engine in the first embodiment of the present invention. 4 is a time chart showing the state of each cylinder at the time of start-up, FIG. 4 is a graph showing the amount of air supplied to the cylinder in the expansion stroke while the engine 1 is stopped, and FIG. Graphs showing the amount of air supplied to the cylinders in the compression stroke during one stop are shown respectively. Hereinafter, description will be made along the flowchart of FIG. 2 with reference to FIGS.

  The combustion order of the engine 1 is in the order of cylinder # A → cylinder # C → cylinder # D → cylinder #B. FIG. 3 shows the compressed air of each cylinder from the time when the ignition switch 32 is turned on. The supply timing, fuel injection timing, and ignition timing are shown. 3 indicates a time point when the crankshaft 20 of the engine 1 actually starts to rotate. Further, in the following description, the members provided in the respective cylinders are denoted by reference numerals corresponding to the cylinders (for example, the combustion chamber 2A in the case of the combustion chamber of the cylinder #A).

  When the ECU 30 receives the start signal from the ignition switch 32, as shown in FIG. 2, first, in step S1, based on the information from the cam angle sensor 26, the stroke of each cylinder at this time, that is, when the engine 1 is stopped, is determined. Determine. Here, as shown in FIG. 3, it is assumed that cylinder #A is in the expansion stroke, cylinder #C is in the compression stroke, cylinder #D is in the intake stroke, and cylinder #B is in the exhaust stroke.

Next, in step S2, the crank angle θo of the cylinder #C in the compression stroke at this time is detected by the crank angle sensor 24, and the process proceeds to step S3. In this embodiment, the TDC (top dead center) is 0 ° in the crank angle, ATDC (after top dead center) in the expansion stroke and intake stroke, and BTDC (before top dead center) in the compression stroke and exhaust stroke. expressed.
In step S3, fuel is supplied from the air assist injectors 6A, 6C, 6D into the combustion chambers 2A, 2C, 2D of the cylinder #A in the expansion stroke, the cylinder #C in the compression stroke, and the cylinder #D in the intake stroke. Inject (a), (b), and (c), and proceed to step S4. Here, the injections (a), (b), and (c) indicate the respective time points of (a), (b), and (c) in FIG. 3, and the respective time points of FIG. ing.

In step S4, compressed air is supplied (d) from the air assist injector 6A into the combustion chamber 2A of the cylinder #A in the expansion stroke, and the amount of air in the combustion chamber 2A is increased.
As shown in FIG. 4, the amount of compressed air supplied at this time is relatively small when the stop position of the piston 16A of the cylinder #A in the expansion stroke is 40 to 80 ° ATDC, and the stop position of the piston 16A is smaller than that. Is set to be relatively large when approaching the top dead center side and the bottom dead center side. This is because when the stop position of the piston 16A is in the vicinity of the top dead center, the amount of air in the combustion chamber is small, and in the case of the vicinity of the bottom dead center, even if combustion occurs, the expansion amount cannot be sufficiently obtained. This is because the start-up deteriorates. Therefore, in such a case, combustion is promoted by supplying a relatively large amount of compressed air.

In step S5, ignition (e) is performed by the spark plug 4A on the mixture in which the fuel injected in step S3 in the combustion chamber 2A of the cylinder #A in the expansion stroke has progressed, and combustion occurs. Then, the process proceeds to step S6. The piston 16A of the cylinder #A is pushed down by the combustion, and the crankshaft 20 starts rotating from this point.
In step S6, it is determined whether or not the crank angle θo detected in step S2 is equal to or larger than a predetermined crank angle θt (for example, 60 ° BTDC). When the determination result is true (Yes), that is, the stop position of the piston 16C of the cylinder #C that was in the compression stroke while the engine 1 was stopped before the crankshaft 20 was rotated is relatively far from the top dead center. If a sufficient amount of air is secured in the combustion chamber 2C, the process proceeds to step S9. On the other hand, if the determination result is false (No), that is, if the stop position of the piston 16C is relatively near the top dead center and the amount of air in the combustion chamber 2C is small, the process proceeds to step S7.

In step S7, it is determined whether or not the cylinder #C that has been in the compression stroke while the engine 1 is stopped has advanced to the expansion stroke due to the rotation of the crankshaft 20 and has reached a predetermined compressed air supply timing. If the determination result is false (No), the determination in step S7 is repeated. On the other hand, if the determination result is true (Yes), the process proceeds to step S8.
In step S8, compressed air is supplied (f) from the air assist injector 6C to the combustion chamber 2C of the cylinder #C that was in the compression stroke while the engine 1 was stopped, and the amount of air in the combustion chamber 2C is increased to step S9. move on.

  As shown in FIG. 5, the amount of compressed air supplied at this time is set so as to increase relatively as the stop position of the piston 16C of the cylinder #C in the compression stroke while the engine 1 is stopped approaches the top dead center side. ing. Such a relationship between the supply air amount and the stop position of the piston 16C is the same as the relationship on the top dead center side from 60 ° ATDC in FIG. On the contrary, when the stop position of the piston 16C is closer to the bottom dead center side than the predetermined position, there is sufficient air in the cylinder, and it is not necessary to supply air and supply additional fuel to burn it. Prohibit air supply.

By setting in this way, the combustion in the cylinder #C is favorably generated and the reaction force at the time of compression of the cylinder #C is suppressed.
In step S9, the spark plug 4C ignites the air-fuel mixture in the combustion chamber 2C of the cylinder #C that was in the compression stroke while the engine 1 was stopped to cause combustion. At this time, the combustion chamber 2C has a sufficient amount of air, so that combustion occurs satisfactorily. As a result, the piston 16C of the cylinder #C is pushed down, and the rotation of the crankshaft 20 is promoted.

  Subsequently, the routine proceeds to step S10, where the fuel injection timing and ignition timing are set to normal operation for each cylinder, and the routine is exited. Here, in the cylinder that is initially ignited after the normal operation, that is, the cylinder #D that is in the intake stroke while the engine 1 is stopped, fuel is injected (c) into the combustion chamber 2D in advance in step S3. Therefore, the air-fuel mixture in the combustion chamber 2D is sufficiently vaporized, and good combustion is generated by igniting (h) the air-fuel mixture, and the engine 1 is reliably started.

Note that the amount of fuel injection (c) in cylinder #D in the intake stroke of step S3 is empty relative to the volume of combustion chamber 2D when intake valve 12D is closed, regardless of the stop position of piston 16D. The fuel ratio is set to an amount that makes the stoichiometric air-fuel ratio.
Further, the amount of fuel injection (a) in the cylinder #A in the expansion stroke of step S3 is the volume in the combustion chamber 2A when the engine 1 of the cylinder #A is stopped and the compressed air supply amount supplied in step S4. The air / fuel ratio is set to the stoichiometric air / fuel ratio with respect to the amount obtained by adding.

  Further, the amount of fuel injection (b) to the cylinder #C in the compression stroke of step S3 is the combustion while the engine 1 of the cylinder #C is stopped when the determination result of step S6 is false (No). The air / fuel ratio is set to an amount corresponding to the theoretical air / fuel ratio with respect to the sum of the volume in the chamber 2C and the compressed air supply amount supplied in step S8, and the determination result in step S6 is true (Yes). In such a case, the air-fuel ratio is set to an amount that makes the stoichiometric air-fuel ratio only for the volume in the combustion chamber 2C when the cylinder #C is stopped.

  As described above, in the direct start in which the engine 1 is started by causing combustion in the cylinder #A in the expansion stroke, fuel is supplied in advance to the cylinder #C in the compression stroke while the engine 1 is stopped. When the stop position of the piston 16C of the cylinder #C is in the vicinity of the top dead center, the compressed air is supplied into the combustion chamber 2C and the amount of air is increased, and ignition is performed. Combustion can be caused, and the startability of the engine 1 by direct start can be improved.

As described above, the internal combustion engine starter according to the present invention can be started well even in the stop range of the engine 1 where start by direct start is difficult, so that quick start by direct start in a wider stop range is possible. And it becomes possible to perform a quiet start.
Further, by supplying fuel in advance to the combustion chamber 2D of the cylinder #D in the intake stroke while the engine 1 is stopped, a sufficient vaporization time can be ensured until the ignition of the cylinder #D. The cylinder #D also generates good combustion, and the startability of the engine 1 can be further improved.

Next, a second embodiment will be described.
Referring to FIG. 6, there is shown a schematic configuration diagram showing an internal combustion engine starter according to a second embodiment of the present invention, which will be described below with reference to FIG. In addition, the same code | symbol is used about the same member as the said 1st Example, and description is abbreviate | omitted about the same function.
In the second embodiment, as shown in the figure, an intake port 42 is formed in the combustion chamber 2 of the engine 40 so as to extend substantially in the width direction of the engine 40 so as to face the exhaust port 10.

An injector 44 (fuel supply means) capable of injecting only fuel faces the intake port 42, and a fuel line 44 a is connected to the injector 44.
In addition, an air injector 46 (compressed air supply means) capable of injecting only compressed air faces the combustion chamber 2, and an air line 46 a is connected to the air injector 46.
Various devices and various sensors such as the spark plug 4, the injector 44, the air injector 46, the crank angle sensor 24, the cam angle sensor 26, and the ignition switch 32 are electrically connected to the ECU 50. The ECU 50 includes various sensors. It controls the operation of various devices based on information from each category.

  Thus, in the second embodiment, the engine 1 of the first embodiment is an in-cylinder injection type engine in which fuel is directly injected into the combustion chamber 2, whereas the engine 40 is placed in the intake port 44 of each cylinder. This is a so-called MPI (multi-point injection) engine of an intake pipe injection type that injects fuel. In the MPI engine, since the injector 44 faces the intake port 42, the supply of fuel into the combustion chamber 2 is limited to a period in which the intake valve 12 is in the communication state in the intake stroke.

The operation of the starter for an internal combustion engine according to the second embodiment of the present invention thus configured will be described below.
Referring to FIGS. 7 to 9, FIG. 7 is a flowchart showing a stop control routine of the engine 40 executed by the ECU 50 in the second embodiment of the present invention, and FIG. 8 is a flowchart showing the ECU 50 in the second embodiment of the present invention. FIG. 9 is a flowchart showing a start control routine of the engine 40 executed by the engine, and FIG. 9 is a time chart showing the state of each cylinder at the time of stopping and starting the engine 40 in the second embodiment. Has been. Hereinafter, description will be made along the flowchart of FIG. 7 with reference to FIGS. 8 and 9.

First, stop control performed by the ECU 50 when the engine 40 is stopped will be described.
When receiving a stop signal from the ignition switch 32, the ECU 40 first stops ignition of each cylinder in step S20 as shown in FIG. Here, FIG. 9 shows the state of each cylinder from the time when the ignition switch 32 is switched off, that is, the time when ignition is stopped. In FIG. 9, the state of each cylinder at that time is shown. Cylinder #A is in the intake stroke, cylinder #C is in the exhaust stroke, cylinder #D is in the expansion stroke, and cylinder #B is in the compression stroke.

When the ignition of each cylinder is stopped in this way, combustion does not occur in each cylinder from the time when the ignition is stopped, but the crankshaft 20 continues to rotate for a while due to inertia.
Next, in step S21, fuel is injected into the cylinder that has reached a predetermined fuel injection timing in the intake stroke, and the process proceeds to step S22. Specifically, fuel is injected (i) into the intake port 42A from the injector 44 of the cylinder #A in the intake stroke when ignition is stopped, and the fuel enters the combustion chamber 2A in which the intake valve 12A is in communication. Supplied.

  Subsequently, in step S22, it is determined whether or not a predetermined amount of fuel preset by the fuel injection has been injected. Here, the specified amount is estimated by estimating the period during which the crankshaft 20 rotates by inertia after the ignition is finished, and at least when the crankshaft 20 stops, the fuel in the combustion chamber of the cylinder that becomes the expansion stroke and the cylinder that becomes the compression stroke Is set to be supplied. If the determination result is false (No), the process returns to step S21, and fuel injection is performed in the cylinder that has reached the predetermined fuel injection timing in the intake stroke. For example, as shown in FIG. 9, when cylinder #C that was in the exhaust stroke at the time of ignition stop reaches a predetermined fuel injection timing in the intake stroke, fuel injection (j) is performed on cylinder #C. To do.

On the other hand, when the prescribed amount of fuel injection is completed and the determination result is true (Yes), the process proceeds to step S23.
In step S23, the fuel injection of each cylinder is stopped, the routine is exited, and the stop control is ended.
As described above, in the stop control performed by the ECU 50 when the engine 40 is stopped, when the stop signal is received from the ignition switch 32, first, the ignition of each cylinder is stopped and the crankshaft 20 is rotating in inertia during the intake stroke. By injecting the fuel into the cylinder, the fuel is supplied to the combustion chamber of the cylinder that becomes the expansion stroke and the cylinder that becomes the compression stroke when the crankshaft is stopped.

Next, start control performed by the ECU 50 when the engine 40 is started will be described.
When the ECU 50 receives the start signal from the ignition switch 32, as shown in FIG. 8, first, in step S30, the ECU 50 determines the stroke of each cylinder based on the information from the cam angle sensor 26. At this time, as shown in FIG. 9, the stop control is completed, cylinder #A is in the expansion stroke, cylinder #C is in the compression stroke, cylinder #D is in the intake stroke, and cylinder #B is in the exhaust stroke. .

Next, in step S31, the crank angle θo of the cylinder #C in the compression stroke at this time is detected by the crank angle sensor 24, and the process proceeds to step S32.
In step S32, compressed air is supplied (k) from the air injector 46A into the combustion chamber 2A of the cylinder #A in the expansion stroke, and the amount of air in the combustion chamber 2A is increased.
In step S33, the air-fuel mixture in the combustion chamber 2A of the cylinder #A that is in the expansion stroke is ignited (l) by the spark plug 4A to the fuel mixture that has been vaporized in the stop control, and the combustion is performed. The process proceeds to step S34. The piston 16A of the cylinder #A is pushed down by the combustion, and the crankshaft 20 starts rotating from this point.

In step S34, it is determined whether or not the crank angle θo detected in step S31 is greater than or equal to a predetermined crank angle θt set in advance. If the determination result is true (Yes), the process proceeds to step S37. On the other hand, if the determination result is false (No), the process proceeds to step S35.
In step S35, it is determined whether or not the cylinder #C that has been in the compression stroke while the engine 40 is stopped has advanced to the expansion stroke due to the rotation of the crankshaft 20 and has reached a predetermined compressed air supply timing. If the determination result is false (No), the determination in step S35 is repeated. On the other hand, if the determination result is true (Yes), the process proceeds to step S36.

In step S36, compressed air is supplied (m) from the air injector 46C to the combustion chamber 2C of the cylinder #C that was in the compression stroke while the engine 40 was stopped, and the amount of air in the combustion chamber 2C is increased, and the process proceeds to step S37. .
In step S37, ignition (n) is performed by the spark plug 4C on the air-fuel mixture in the combustion chamber 2C of the cylinder #C that was in the compression stroke while the engine 40 was stopped to cause combustion. At this time, since the combustion chamber 2C has a sufficient amount of air together with the fuel supplied during the stop control, combustion occurs satisfactorily, thereby pushing down the piston 16C of the cylinder #C and the crankshaft. Promote 20 rotations.

Subsequently, the routine proceeds to step S38, where the fuel injection timing and ignition timing are set to normal operation for each cylinder, and the routine is exited.
As described above, in the start control performed by the ECU 50 when the engine 40 is started, the fuel is supplied in advance into the combustion chambers 2A and 2C in the stop control, and the fuel is sufficiently vaporized while the engine 40 is stopped. Therefore, combustion occurs satisfactorily in the cylinder #A in the expansion stroke and the cylinder #C in the compression stroke at the start, and the startability by direct start can be improved even in the MPI engine.

  As described above, in the internal combustion engine starter according to the present invention, even when the fuel supply to the combustion chamber 2 is an MPI engine that is limited to a period in which the intake valve 12 is in the communication state during the intake stroke. By injecting fuel during the intake stroke while the crankshaft 20 is inertially rotating when the engine 40 is stopped, the start by the direct start at the next start of the engine 40 can be performed satisfactorily, and it is quick and quiet. Start-up can be realized.

Although the description of the embodiment of the starter for the internal combustion engine according to the present invention has been completed, the embodiment is not limited to the above embodiment.
For example, in the first example of the above embodiment, the air assist injector 6 capable of injecting fuel and compressed air is used, but instead of this, an injector that injects only fuel and only compressed air is injected. The air injectors may be configured to face the combustion chamber 2 independently.

  In the above embodiment, the start signal and the stop signal are sent to the ECUs 30 and 50 by switching the ignition switch 32 ON and OFF. However, for example, a specific condition is satisfied even when the ignition switch 32 is in the ON state. The stop signal may be sent to the ECUs 30 and 50, and the present invention can be suitably applied to a so-called idle stop vehicle.

In the above-described embodiment, the cylinder discrimination is performed by the cam angle sensor 26. However, the cylinder discrimination means is not limited to this, and for example, calculation from a crank angle or other devices may be used.
In the second example of the above-described embodiment, the specified amount of fuel is injected in the stop control of the engine 40. However, the present invention is not limited to this configuration. For example, the crankshaft 20 is particularly stopped. It is also possible to inject fuel into a cylinder that has reached a predetermined fuel injection timing in the intake stroke until the crankshaft 20 naturally stops without estimating the period until it is done.

  In the above embodiment, the engine 1 or 40 may be provided with a starter, and when the start by the direct start fails, the starter may be started.

1 is a schematic configuration diagram of a starter for an internal combustion engine according to a first embodiment of the present invention. It is a flowchart which shows the starting control routine of the engine which ECU performs in 1st Example of this invention. 3 is a time chart showing the state of each cylinder at the time of starting the engine in a first embodiment of the present invention in time series. 6 is a graph showing the amount of air supplied to a cylinder in an expansion stroke while the engine is stopped. 6 is a graph showing the amount of air supplied to a cylinder in a compression stroke while the engine is stopped. It is a schematic block diagram which shows the starting device of the internal combustion engine which concerns on 2nd Example of this invention. It is the flowchart which showed the engine stop control routine which ECU executes in 2nd execution example of this invention. 6 is a flowchart showing an engine start control routine executed by an ECU in a second embodiment of the present invention. It is the time chart which showed the state of each cylinder at the time of the stop of the engine in the 2nd Example of this invention, and starting at the time series.

Explanation of symbols

1, 40 engine (internal combustion engine)
2 Combustion chamber 4 Spark plug (ignition means)
6 Air assist injector (fuel injection means, compressed air supply means)
8, 42 Intake port 12 Intake valve 24 Crank angle sensor (piston position detection means)
26 Cam angle sensor (cylinder discrimination means)
30, 50 ECU
32 Ignition switch 44 Injector (fuel injection means)
46 Air injector (compressed air supply means)

Claims (4)

An internal combustion engine having a plurality of cylinders;
Cylinder discrimination means for discriminating each stroke of the plurality of cylinders;
Piston position detection means for detecting each piston position of the plurality of cylinders;
Fuel supply means for supplying fuel to each combustion chamber of the plurality of cylinders;
Compressed air supply means for directly supplying compressed air to the combustion chambers of the plurality of cylinders;
Ignition means for performing ignition in each combustion chamber of the plurality of cylinders;
Fuel is supplied by the fuel supply means to the respective combustion chambers of the cylinders in the expansion stroke and the cylinders in the compression stroke while the internal combustion engine is stopped as determined by the cylinder determination means while the internal combustion engine is stopped. Alternatively, the compressed air supply means supplies compressed air to the combustion chamber of the cylinder in the expansion stroke before ignition by the ignition means in the cylinder in the expansion stroke while the internal combustion engine is stopped. And when the piston position detected by the piston position detecting means of the cylinder that was in the compression stroke while the internal combustion engine was stopped was at the top dead center side than the predetermined position, the cylinder that was in the compression stroke Before the ignition by the ignition means, the compressed air is supplied into the combustion chamber of the cylinder that was in the compression stroke, and the internal combustion engine is stopped by the ignition means to start the internal combustion engine. Control means for igniting a cylinder in the expansion stroke and controlling the cylinder in the compression stroke to ignite after the cylinder in the compression stroke shifts to the expansion stroke while the internal combustion engine is stopped; ,
A starter for an internal combustion engine comprising:   The compressed air supply means changes the amount of compressed air to the cylinder in the compression stroke according to the piston position detected by the piston position detection means of the cylinder in the compression stroke while the internal combustion engine is stopped. 2. The starter for an internal combustion engine according to claim 1, wherein Determining the cylinder in the intake stroke while the internal combustion engine is stopped by the cylinder determining means;
3. The starter for an internal combustion engine according to claim 1, wherein fuel is supplied or supplied also to a combustion chamber of a cylinder in the intake stroke while the internal combustion engine is stopped. The fuel supply means is provided to face each intake port of the plurality of cylinders,
The control means is discriminated by the cylinder discrimination means by supplying fuel into the combustion chamber during the intake stroke from when the ignition by the ignition means is stopped by the fuel supply means until the internal combustion engine is stopped. 3. The starter for an internal combustion engine according to claim 1, wherein fuel is supplied to a combustion chamber of a cylinder in the expansion stroke and a cylinder in the compression stroke while the internal combustion engine is stopped.

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