JP2001173487A - Direct cylinder injection type engine starting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce power consumption and to improve a starting feeling by starting an engine in early stages, in a direct cylinder injection type engine starting device. SOLUTION: A cylinder disposed in a compression stroke of a stopped engine 11 is specified, and when remaining time in the compression stroke is longer than a predetermined period at the time of starting, fuel is injected to not only the specified cylinder but also a cylinder in the last time compression stroke. On the other hand, when the remaining time in the compression stroke is shorter than the predetermined period, fuel injection to the specified cylinder is prohibited, and fuel injection is carried out to a cylinder which becomes a compression stroke in the next time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a starting device applied to a direct injection type engine which directly injects fuel into a combustion chamber.

[0002]

2. Description of the Related Art In a direct injection type multi-cylinder engine,
In order to perform fuel injection control or ignition timing control, it is necessary to identify a cylinder at the time of starting, for example, identify which cylinder is in which stroke. When cylinder identification is performed based on the crank angle and the cam angle, fuel injection and ignition are performed for each cylinder during the intake stroke.

For example, in a four-cylinder in-cylinder injection engine, one cycle (intake stroke, compression stroke, explosion stroke, exhaust stroke) is performed by rotating the crankshaft twice (270 °). Crankshaft 2
With the rotation, the SGT signal is output from the crank angle sensor, and the SGC signal is output from the cam angle sensor. Therefore, when the engine is started, which cylinder is in the compression top dead center position (explosion stroke) is identified based on the level of the SGC signal with respect to the fall and rise of the SGT signal, and fuel injection and ignition are performed from the cylinder in the intake stroke. Start.

[0004]

However, in such a conventional method of starting an in-cylinder injection type engine, one cylinder stroke is required for cylinder identification, and then the intake stroke, compression stroke, and explosion stroke are required. Therefore, the fuel is injected during the intake stroke and ignited during the explosion stroke, and the ignition is performed on the fourth stroke from the start of the engine and the engine is started at the earliest. For this reason, there is a problem that the energization time to the ignition plug becomes long and a large amount of battery power is consumed.

[0005] The applicant of the present application has already filed Japanese Patent Application No. 11-7.
No. 3362, as a "starting device for a direct injection internal combustion engine", a cylinder located in a compression stroke of a stopped internal combustion engine is specified, and fuel injection is performed for the remaining compression stroke of the cylinder specified at the start of the internal combustion engine. Has been filed to enable early start of the internal combustion engine. However, in this application, there is still room for improvement in the control according to the position of the specified cylinder in the compression stroke and the control for the specific difference of the cylinder due to the reverse rotation when the engine is stopped.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problem, and a starting device for a direct injection type engine in which the power consumption is reduced by starting the engine early and the starting feeling is improved. The purpose is to provide.

[0007]

According to the first aspect of the present invention, there is provided a starting apparatus for a direct injection type engine in which a compression stroke cylinder discriminating means is located in a compression stroke of a stopped engine. The fuel injection control means executes fuel injection to the specified cylinder when the remaining period in the compression stroke is longer than a predetermined period at the time of starting the engine, and specifies when the remaining period is shorter than the predetermined period. In addition, the fuel injection to the cylinder that has failed is prohibited, and the fuel injection is executed to the cylinder that will be the next compression stroke.

Therefore, when cranking for starting is started, fuel is injected into the cylinder when the remaining period of the compression stroke is long, and fuel is injected into the cylinder which will be the next compression stroke when the remaining period is short. , The corresponding cylinder is immediately ignited and no fuel is injected into the non-ignitable cylinder, enabling early engine start-up, reducing power consumption, and improving exhaust gas performance while preventing fuel consumption from deteriorating. The starting feeling can be improved.

According to a second aspect of the present invention, the compression stroke cylinder discriminating means specifies a cylinder located in the compression stroke of the stopped engine, and the fuel injection control means determines whether or not the engine has started. Fuel injection is executed for the specified cylinder and the cylinder that was in the compression stroke last time.

Therefore, even if the crankshaft rotates backward and stops when the engine is stopped, fuel is injected into the cylinder that was in the previous compression stroke, so that the engine can be started reliably.

[0011]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a schematic diagram showing a starting device for a direct injection type engine according to an embodiment of the present invention, FIG. 2 is a flowchart showing control when the engine is stopped, and FIG. 3 is a flowchart showing control when starting the engine. 4 and 5 show time charts at the time of engine start when the engine stop state corresponds to Case 1, and FIG. 6 shows time charts at the time of engine start when the engine stop state corresponds to Case 2.

In the present embodiment, as shown in FIG.
The engine 11 is a four-cylinder in-cylinder injection-type spark ignition engine.
2 and an injector 13 are attached, and fuel is directly injected from the injector 13 into a combustion chamber (not shown). In the engine 11, it is possible to switch between a compression stroke injection mode in which fuel injection is performed in a compression stroke and an intake stroke injection mode in which fuel injection is performed in an intake stroke. It is possible to perform stratified combustion that achieves a super-lean overall air-fuel ratio after forming an air-fuel mixture near the air-fuel ratio. In the intake stroke injection mode, uniform combustion that forms a uniform air-fuel mixture in the combustion chamber becomes possible. I have. A belt-type continuously variable transmission (CVT) 15 is connected to the engine 11 via a clutch 14.
The output shaft of the CVT 15 is connected to left and right drive wheels via a front differential (not shown).

A starter 16 which is always meshed with the engine 11 is mounted on a pinion gear 17 of the starter 16.
Are engaged with the flywheel 18 of the engine 11. In this starter 16, a starter motor 19 is connected to a battery 21 via a normally open relay contact 20, and a relay coil 22 corresponding to the relay contact 20 is connected to the battery 21 via an ST contact 24 of an ignition switch 23. Have been. Therefore, when the ignition switch 23 is operated to the position of the ST contact 24, the relay contact 20 is closed by the excitation of the relay coil 22, the starter motor 19 is energized, and the engine 11 is cranked by the starter 16. The relay coil 22 of the starter 16 is provided with a controller 25 for controlling the starter.
O of the relay contact 26 and the ignition switch 23
A relay coil 28 connected to the battery 21 via an N contact 27 is
1 connected. Therefore, even if the ignition switch 23 is at the position of the ON contact 27, the relay coil 2
When the relay contact 26 is closed by the excitation of 8, the starter motor 19 is energized to perform cranking.

The vehicle includes an engine 11 and a CVT 15.
There is provided an electronic control unit (ECU) 29 for controlling the operation and the like. The ECU 29 includes an input / output device, a storage device for storing a control program and a control map, a central processing unit, and a timer and counters. This ECU
29 controls the in-cylinder injection engine 11 comprehensively. The engine 11 is provided with a crank angle sensor 30 that outputs a crank angle signal SGT at a predetermined crank position.
A cam angle sensor 31 that outputs GC is provided. That is, in addition to the crank angle sensor 30 and the cam angle sensor 31, detection information of various sensors such as a shift position sensor 32, a throttle position sensor (not shown), an air flow sensor, and an accelerator position sensor, and a signal of the ignition key switch 23 are transmitted to the ECU 29. Is input to the ECU 29 based on detection information of various sensors.
The fuel injection mode, the fuel injection amount, the ignition timing, and the like are determined, and the driving of the ignition plug 12, the driver of the injector 13, the drive motor of the throttle valve, and the like are controlled.

In the in-cylinder injection type engine 11 configured as described above, the ECU 29 specifies a cylinder located in the compression stroke of the stopped engine 11 (compression stroke cylinder discriminating means), and starts the compression stroke in the compression stroke. When the remaining period is longer than the predetermined period, fuel injection is performed for the specified cylinder.On the other hand, when the remaining period in the compression stroke is shorter than the predetermined period, fuel injection to the specified cylinder is prohibited and the next compression is performed. The fuel injection is performed (fuel injection control means) with respect to the cylinder to be processed. Also,
When the engine 11 is started, when the remaining period in the compression stroke is longer than a predetermined period, in addition to the specified cylinder,
Fuel injection is executed for the cylinder that was in the previous compression stroke.

In this case, the compression stroke cylinder discriminating means includes the crank angle sensor 30 and the cam angle sensor 31, and identifies the compression cylinder when the engine is stopped based on the crank angle signal SGT and the cam rotation position signal SGC. That is, which cylinder is at the compression top dead center position (explosion stroke) is identified based on the level of the SGC signal with respect to the fall and rise of the SGT signal, and the cylinder stopped in the compression stroke is stored in the ECU 29 based on that. Further, in which period in the compression stroke the cylinder stopped in the compression stroke is located, that is, in the present embodiment, the stop position in the compression stroke is 75 in the cylinder specified as the compression stroke. If it is earlier than BTDC (when the remaining period is longer than a predetermined period), it is specified as Case 1, and after (when the remaining period is shorter than the predetermined period), it is specified as Case 2 and stored in the ECU 29.

Further, in the cylinder specified to be in the compression stroke when the engine 11 is stopped, the stop position of the cylinder is 75 ° BTDC.
In the earlier case (case 1), the engine 11 was stopped during the early to middle stages of the compression stroke (before the piston was raised), and the engine 11 was stopped in the latter half of the compression stroke (before the piston was raised) due to reverse rotation. Case. If the engine 11 stops in the early stage of the compression stroke after returning to the reverse direction, since the crank angle signal SGT has already been output,
The ECU 29 specifies not the cylinder actually stopped but the cylinder that will be the next compression stroke as the cylinder stopped in the compression stroke. Therefore, in case 1, when the engine 11 is started, fuel is injected into the cylinder specified to have stopped in the compression stroke and the cylinder in the previous compression stroke, and thereafter, the crank angle signal SGT and the cam rotation position signal After accurately identifying the cylinder based on the SGC, the fuel is injected in the compression stroke of the correct cylinder.

Here, the control of the in-cylinder injection type engine according to this embodiment by the starting device will be described with reference to the flowcharts of FIGS. 2 and 3 and the time charts of FIGS. 4, 5 and 6.

First, in the control when the engine 11 is stopped, as shown in FIG.
It is determined whether or not 1 has stopped, for example, based on the output of an engine speed sensor. In this case, there are a manual stop by an OFF operation of the ignition key switch 23 by a driver, an automatic stop by an idle stop, and an engine stop by a battery power or a driving state in a hybrid vehicle. For example, when the shift lever is in the neutral position, the vehicle speed is zero, and the brake switch is turned off,
When N and the like are established, the engine 11 is stopped.

When the engine 11 is stopped in step 11, the engine 1 is stopped in step S12 based on the crank angle signal SGT of the crank angle sensor 30 and the cam rotation position signal SGC of the cam angle sensor 31, as described above.
The ECU 29 identifies the cylinder in the compression stroke when the engine 1 is stopped,
To memorize. Then, in step 13, it is determined whether or not the stop position of the cylinder stopped in the compression stroke is before 75 ° BTDC, that is, whether the crank angle signal SGT is at the LOW level. In step S15, case 2 is set if the signal is not at the low level but at the high level. In this way, when the engine 11 is stopped, the ECU 29 stores the case 1 or the case 2 according to the cylinder in the compression stroke and the stop position of the cylinder stopped in the compression stroke.

Next, in the control for starting the engine 11, as shown in FIG.
1 in the ECU 29, for example, whether the driver has turned on the ignition key switch 23, or in the idle stop state.
The engine 11 is restarted when preset restart conditions, for example, a traveling position of the shift lever, ON of an accelerator pedal switch, and the like are satisfied. Step S22
Then, it is determined whether or not normal fuel injection has already been started, and if normal fuel injection has been started, step S
At 35, normal fuel injection and ignition control is continued.

On the other hand, if the normal fuel injection has not been started in step S22, in step S23 the EC
The stop state of the engine 11 stored in U29 is read, and it is determined whether or not the case 1 is satisfied. If the stopped state of the engine 11 corresponds to case 1 in step S23, it is confirmed in step S24 that there is a cylinder memory at the time when the engine 11 was stopped last time. It is determined whether or not the process has been completed, and if the cylinder identification has not been completed, the process proceeds to step S26.

Then, in step S26, the rise (HIGH) of the crank angle signal SGT is waited, and in step S27, the injector 13 at 75 ° BTDC with respect to the stored cylinder and the cylinder which was in the previous compression stroke. Fuel injection is executed, and the ignition coil is energized at 75 ° BTDC to the stored cylinder and the cylinder that was in the previous compression stroke at 75 ° BTDC to ignite the ignition plug 12 in step S28.
Then, in step S29, a fall (LOW) of the crank angle signal SGT is waited, and in step S30, the energization of the ignition coil is stopped.

The start control in the case where the stop state of the engine 11 is the case 1 will be specifically described. As shown in FIG. 4, the cylinder identified as having stopped the engine 11 in the compression stroke is the # 4 cylinder. When the crank angle signal SGT
Stop position is before 75 ° BTDC. When the engine 11 is started from this state, the ECU 29 executes fuel injection to the specified # 4 cylinder and also to the # 3 cylinder which was in the previous compression stroke, and subsequently to the # 4 cylinder and # 3
Ignite the cylinder. Then, it is determined whether the # 2 cylinder is at the compression top dead center position based on the level of the SGC signal with respect to the subsequent fall and rise of the SGT signal, and it is confirmed that the cylinder stopped in the compression stroke is the # 4 cylinder. In this case, fuel injection and ignition were performed on the # 3 cylinder. However, at this time, the fuel was not ignited due to the explosion stroke, and thereafter, the fuel injection and ignition were performed on the # 2, # 1, and # 3 cylinders in that order.

On the other hand, as shown in FIG. 5, since the stop position of the crank angle signal SGT is before 75 ° BTDC (dotted line position), the cylinder identified as having stopped the engine 11 in the compression stroke is # 4. Even in the case of a cylinder, the engine 11 sometimes reverses and stops, and in this case, the actual stop position of the engine 11 is further to the front (the position indicated by a chain line).
The cylinder stopped in the compression stroke is # 3 cylinder. in this case,
When the engine 11 is started, the ECU 29 executes fuel injection and ignition on the specified # 4 cylinder and # 3 cylinder in the same manner as described above. However, the # 4 cylinder does not ignite because it is in the intake stroke, and only the # 3 cylinder in the compression stroke ignites. Then, by identifying whether the # 4 cylinder is at the compression top dead center position based on the level of the SGC signal with respect to the subsequent fall and rise of the SGT signal, the cylinder stopped in the compression stroke is not the # 4 cylinder, but the # 3 cylinder. After confirming that the cylinder is a cylinder, fuel injection and ignition are performed in the order of # 4, # 2, and # 1 cylinders. In the # 4 cylinder, fuel has already been injected in the intake stroke, and the amount of fuel injected in the compression stroke can be reduced. The stoichiometric air-fuel ratio of the fuel injected in the intake stroke and the fuel injected in the compression stroke is reduced. As a result, a stratified combustion that forms a nearby air-fuel mixture and achieves a lean overall air-fuel ratio is realized, so that fuel efficiency is not deteriorated and raw gas generated by fuel injected in the intake stroke is not discharged to the outside.

Returning to FIG. 3, when the stopped state of the engine 11 does not correspond to Case 1 in Step S23 (corresponding to Case 2), or when there is no cylinder memory when the engine 11 last stopped in Step S24. , Step S3
Step S3 after completing the cylinder identification by shifting to 1
Then, if the cylinder identification is completed in step S25, the process proceeds to step S32. Then, in this step S32, the rising (HIGH) of the crank angle signal SGT is waited, and in step S33, the fuel injection is executed by the injector 13 at 75 ° BTDC to the identified cylinder, and in step S34, this fuel injection is performed. The identified cylinder is energized at 75 ° BTDC to the ignition coil and ignited by the ignition plug 12. Then, in step S29, a fall (LOW) of the crank angle signal SGT is waited, and in step S30, the energization of the ignition coil is stopped.

The start control when the engine 11 is stopped in Case 2 will be specifically described. As shown in FIG. 6, the cylinder identified as having stopped the engine 11 in the compression stroke is the # 4 cylinder. When the crank angle signal SGT
Stops after 75 ° BTDC. When the engine 11 is started from this state, the ECU 29 does not execute the fuel injection to the specified # 4 cylinder, but executes the fuel injection to the # 2 cylinder which will be the next compression stroke.
Ignition for two cylinders. At this time, whether the # 2 cylinder is at the compression top dead center position is identified based on the level of the SGC signal with respect to the fall and rise of the SGT signal,
It is confirmed that the cylinder stopped in the compression stroke is # 4 cylinder.

In the above-described embodiment, the fuel injection is performed on the cylinder whose cylinder identification is completed. However, the fuel may be simply injected on the cylinder which is to be in the compression stroke next to the storage cylinder.

[0030]

As described in detail in the above embodiment, according to the first aspect of the present invention, the cylinder located in the compression stroke of the stopped engine is identified and the engine is started. When the remaining period in the compression stroke is longer than the predetermined period at the start of the fuel injection, the fuel injection is performed for the specified cylinder, while when the remaining period is shorter than the predetermined period, the fuel injection to the specified cylinder is prohibited. Since fuel injection is executed for the cylinder that will be the next compression stroke, the cylinder located in the compression stroke is immediately ignited, and fuel is not injected into the cylinder that cannot be ignited, enabling early engine start. As a result, power consumption can be reduced, and at the same time, deterioration of fuel efficiency can be prevented while improving exhaust gas performance, and the starting feeling can be improved.

According to the second aspect of the present invention, the cylinder located in the compression stroke of the stopped engine is specified, and the cylinder specified at the start of the engine and the previous cylinder are specified. Since fuel injection is performed for the cylinders that were in the compression stroke, even if the crankshaft rotates backward and stops when the engine stops, fuel is injected into the cylinders that were in the previous compression stroke. Since the fuel is injected, the engine can be reliably started.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram illustrating a starting device for a direct injection engine according to an embodiment of the present invention.

FIG. 2 is a flowchart illustrating control when the engine is stopped.

FIG. 3 is a flowchart illustrating control at the time of starting an engine.

FIG. 4 is a time chart at the time of engine start when the engine stop state corresponds to Case 1;

FIG. 5 is a time chart when the engine is started when the engine stopped state corresponds to Case 1;

FIG. 6 is a time chart at the time of engine start when the engine stop state corresponds to Case 2;

[Explanation of symbols]

 Reference Signs List 11 engine 12 injector 13 spark plug 15 belt-type continuously variable transmission (CVT) 16 starter 21 battery 29 electronic control unit, ECU (fuel injection control means) 30 crank angle sensor (compression stroke cylinder discriminating means) 31 cam angle sensor (compression) Stroke cylinder discriminating means)

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Nobuaki Murakami, Inventor 5-33-8 Shiba, Minato-ku, Tokyo Mitsubishi Motors Corporation F-term (reference) 3G084 AA03 AA04 BA13 BA15 CA01 CA03 CA07 DA02 EA04 EA07 EA11 EB06 EC02 FA06 FA07 FA10 FA36 FA38 FA39 3G301 HA04 HA06 HA16 JA02 KA01 KA04 KA07 KA28 LB04 MA11 MA19 MA24 NA08 NB11 NC01 NE23 PA01Z PA11Z PE03Z PE04Z PE05Z PF03Z PF05Z PF07Z PF16Z

Claims (2)

[Claims] In a direct injection type engine in which fuel is directly injected into a combustion chamber, a compression stroke cylinder discriminating means for specifying a cylinder located in a compression stroke of the stopped engine, When the remaining period is longer than a predetermined period, fuel injection is performed for the cylinder specified by the compression stroke cylinder determining unit. On the other hand, when the remaining period in the compression stroke is shorter than the predetermined period, the fuel injection is performed by the compression stroke cylinder determining unit. A fuel injection control means for prohibiting fuel injection to a selected cylinder and executing fuel injection to a cylinder which is to be subjected to a next compression stroke. 2. An in-cylinder injection type engine for directly injecting fuel into a combustion chamber, a compression stroke cylinder discriminating means for specifying a cylinder located in a compression stroke of the stopped engine, and a compression stroke when starting the engine. A cylinder injection type engine starting device, comprising: a fuel injection control unit for executing fuel injection to a cylinder specified by a cylinder discrimination unit and a cylinder which was in a previous compression stroke.