JP2000265878A - Starting device for direct injection type internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the delay in the cylinder judgment, and to rapidly complete the start by judging the cylinder while an internal combustion engine is in operation, keeping the information on the cylinder judgment in the judgment information keeping means when the internal combustion engine is stopped, and controlling the start based on the kept cylinder judgment information when the internal combustion engine is started. SOLUTION: When an engine 1 is in operation, the output signal of a crank angle sensor 23 and a cam angle sensor 24 is read by an ECU 21, a new compression stroke cylinder and piston position are calculated based on the detected crank angle signal and the TOP signal to update the information on the compression stroke cylinder and the piston position which is previously stored in a storage device. Then, presence/ absence of the engine start command is judged, and when the starting condition is established while the engine is automatically stopped waiting for the signal, the information on the compression stroke cylinder and the piston position is read from the storage device to judge whether or not the engine is in an ignitable range based on the engine temperature and the piston position by an engine temperature sensor 22, and to control the start.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a starting device used in a direct injection type internal combustion engine (hereinafter referred to as an engine) for directly injecting fuel into a combustion chamber.

[0002]

2. Related Background Art In recent years, in-cylinder injection engines for directly injecting fuel into a combustion chamber have been put to practical use in order to achieve a reduction in emissions and an improvement in fuel efficiency. The control procedure at the time of starting this type of engine is the same as that of an engine that injects fuel into a normal intake pipe. For example, as described in JP-A-9-236036, first, cranking and cam pulse are started by starting cranking. Cylinder determination based on the
After the completion of the cylinder discrimination, the fuel injection control and ignition timing control for starting are executed based on the cylinder discrimination information, and when the start is completed, the control is switched to the normal control.

[0003] By the way, there has been a demand for shortening the required time at the time of starting, and in the engine of the intake pipe injection,
Until the cylinder discrimination is completed, fuel is injected into all the cylinders all at once, thereby taking measures to prevent a start delay due to the cylinder discrimination processing.

[0004]

However, in a direct injection type engine that injects fuel directly into the combustion chamber, if simultaneous injection is performed, fuel is also injected into a cylinder during an exhaust stroke or an expansion stroke. There was a problem that the countermeasure could not be implemented and the time required for starting was prolonged. SUMMARY OF THE INVENTION An object of the present invention is to provide a starting device for a direct injection internal combustion engine capable of eliminating a delay caused by a cylinder discrimination process and quickly starting the engine.

[0005]

In order to achieve the above object, according to the present invention, cylinder discrimination is performed by cylinder discriminating means during operation of an internal combustion engine, and the cylinder discrimination information is output while the internal combustion engine is stopped. Holding in the holding means, based on the cylinder discriminating information held in the discriminating information holding means at the start of the internal combustion engine,
The starting control means executes the starting control. Therefore, the start control can be started immediately without performing the cylinder discrimination processing.

The present invention is preferably a cylinder discriminating means for discriminating a cylinder while the internal combustion engine is operating, a discriminating information holding means for holding the cylinder discriminating information of the cylinder discriminating means while the internal combustion engine is stopped, Discrimination information updating means for updating the cylinder discrimination information of the discrimination information holding means when the crank angle changes while the internal combustion engine is stopped; and a cylinder held by the discrimination information holding means when the internal combustion engine is started. And a start control means for executing start control based on the discrimination information. This makes it possible to always execute the start control based on the appropriate cylinder discrimination information.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a starting device for a direct injection type engine used in an idle stop vehicle will be described below. In the overall configuration diagram of FIG.
Is an in-cylinder injection type gasoline engine, which is configured as a four-cycle in-line four-cylinder that explodes at equal intervals of 180 ° CA, each of which is equipped with a spark plug 2 and directly injects fuel into the combustion chamber. A fuel injection valve 3 is mounted as possible. The combustion chamber and the intake system of the engine 1 are designed exclusively for in-cylinder injection. When fuel is injected in the compression stroke, the injected fuel is transferred by the reverse tumble flow generated by the intake air, and It enables stratified combustion in which an air-fuel mixture in the vicinity of the stoichiometric air-fuel ratio is formed around the air-fuel mixture and then burns at a super-lean overall air-fuel ratio.

[0008] A manual transmission 4 is connected to the engine 1, and this transmission is connected to driving wheels of the vehicle via a differential gear (not shown). A clutch 5 is provided between the engine 1 and the transmission 4. The clutch 5 controls power transmission from the engine 1 to the transmission 4 according to a clutch operation by a driver. The engine 1 is provided with a constantly meshing starter 6, and a pinion gear 6 a of the starter 6 is always meshed with the flywheel 1 a of the engine 1. The flywheel 1a is provided with a one-way clutch (not shown).
The crankshaft is transmitted to the engine 1 to perform cranking, and idles after the start is completed, thereby preventing the starter 6 from being reversely driven by the engine 1.

The motor 11 of the starter 6 is connected to the battery 13 via a normally open relay contact 12a, and the relay coil 12b corresponding to the relay contact 12a is connected to the battery 1 via the ST contact 14a of the ignition switch 14.
3 is connected. Therefore, the ignition switch 1
When the switch 4 is operated to the position of the ST contact 14a, the relay contact 12a is closed by excitation of the relay coil 12b, the motor 11 is energized, and the engine 1 is cranked by the starter 6. Also, the relay coil 12 of the starter 6
b is the relay contact 1 of the starter control controller 15
The relay coil 15b is connected to the battery 13 via an ON contact 14b of the ignition switch 14 and the relay contact 15a. Therefore, even if the ignition switch 14 is at the position of the ON contact 14b, the relay coil 15b
When the relay contact 15a is closed by the excitation of the motor 11, the motor 11 is energized to perform cranking.

In the passenger compartment, an input / output device (not shown), a storage device (ROM, RAM, BURAM, etc.) for storing control programs and control maps, etc., and a central processing unit (C
PU), an ECU 21 (engine control unit) including a timer counter and the like. On the input side of the ECU 21, an engine temperature sensor 22 for detecting the temperature T of the engine 1, a crank angle sensor 23 for outputting a crank angle signal with the rotation of the crankshaft of the engine 1, and a TOP signal with the rotation of the camshaft. , A vehicle speed sensor 25 for detecting the vehicle speed V, a clutch sensor 26 for detecting the operation state of the clutch 5, an accelerator sensor 27 for detecting the accelerator operation amount Acc, and the transmission 4
Shift position sensor 28 for detecting the shift position of
And other various switches and sensors.

The output side of the ECU 21 is connected to the ignition plug 2 and the fuel injection valve 3 as well as the relay coil 15b of the starter control controller 15. The ECU 21 executes various controls for operating the engine 1, including fuel injection control and ignition timing control, based on the above-described respective detection information, and executes an automatic stop / start process of the engine 1 when the vehicle is stopped such as at a traffic light. .
Further, at the time of starting the engine, the ECU 21 executes a dedicated control for starting to achieve early starting.

The ECU 21 according to the present embodiment continues to operate even when the ignition switch 14 is turned off, for example, when the vehicle is parked, while the ignition switch 14 is being turned off. (Including information on a compression stroke cylinder and a piston position P described later). In the in-cylinder injection engine 1 configured as described above, in addition to uniform combustion in which fuel is injected in a normal intake stroke to form a uniform air-fuel mixture in a combustion chamber, fuel is injected in a compression stroke, and It enables stratified combustion to burn at a lean overall air-fuel ratio. The stratified combustion is generally performed in a low-rotation, low-load operating region.
Is the accelerator operation amount A detected by the accelerator sensor 27
The compression stroke injection is executed in a region where the target average effective pressure Pe (representing the engine load) obtained from the cc or the like and the engine rotation speed Ne obtained from the crank angle signal of the crank angle sensor 23 are relatively low, thereby reducing the emission. Fuel efficiency is improved, and intake stroke injection is executed in a higher region to secure required engine torque.

Next, an outline of an automatic stop / start process of the engine 1 specific to an idle stop vehicle will be described. ECU 21
When a running vehicle stops at a traffic light or the like, the engine 1 is automatically stopped when a preset engine stop condition is satisfied, and the engine 2 is automatically started when a preset engine start condition is satisfied. Thus, emissions and fuel consumption during a stop are prevented. The engine stop conditions include that the vehicle speed V detected by the vehicle speed sensor 25 is zero, that the clutch sensor 26 has not detected the stepping-on operation of the clutch 5 (clutch connection state), and that the shift position sensor 28 It is set that the detected shift position is an N (neutral) position, and when these conditions are satisfied, the ECU 21
Determines that the engine stop condition is satisfied, stops the fuel injection control and the ignition timing control, and stops the engine 1.

The engine start conditions are that the clutch sensor 26 detects the depression operation of the clutch 5 (clutch disengaged state) and that the shift position detected by the shift position sensor 28 is the N position. Is set, and when these conditions are satisfied, the ECU 21
Determines that the engine start condition is satisfied, excites the relay coil 15b of the starter control controller 15, and restarts the injection control and the ignition timing control. Since the relay contact 15a is closed by the excitation of the relay coil 15b, the motor 11 of the starter 6 is energized to perform cranking, and the engine 1 is started and can be started.

The starting and stopping of the engine by a normal driver is the same as in a general vehicle. When the ignition switch 14 is operated to the position of the ST contact 14a, the motor 11 of the starter 6 is energized to crank. Is performed, the fuel injection control and the ignition timing control are started by the ECU 21, and the engine 1 is started.
Switch 14 is turned on during operation of
Is returned to an OFF contact or the like (not shown) from the ECU 21
The fuel injection control and the ignition timing control are stopped, and the engine 1 is stopped.

Next, the starting control executed by the starting device for the in-cylinder injection type engine 1 configured as described above will be described. The ECU 21 executes the main routine shown in FIGS. 2 and 3 at a predetermined control interval. First, as a premise of the description, the engine 1 is in the state of the automatic stop described above or stopped by the OFF operation of the ignition switch 14, and the cylinder in the compression stroke of the engine 1 (hereinafter referred to as the compression stroke cylinder) is stored in the storage device of the ECU 21. ) And information on the piston position P of the cylinder. These pieces of information are calculated based on a crank angle signal detected by the crank angle sensor 23 immediately before the engine is stopped and a TOP signal detected by the cam angle sensor 24.

Here, in the four-cycle in-line four-cylinder, any one of the cylinders is always located in the compression stroke, so that the compression-stroke cylinder is always specified. Further, the crank angle when the engine is stopped is concentrated around BTDC 90 ° CA. This is because, in the in-line four-cylinder engine of this embodiment, any one cylinder reaches the compression top dead center at every 180 ° CA, so even if it stops near the compression top dead center, it reverses by receiving the compression reaction force. It is. Therefore, correspondingly, BTDC is stored in the storage device.
Information on the piston position P around 90 ° CA is stored.

First, the ECU 21 reads the crank angle signal of the crank angle sensor 23 and the TOP signal of the cam angle sensor 24 in step S2, and determines in step S4 whether the signals have changed. For example, when the stopped vehicle moves due to the inclination of the road surface or the like and the crank angle of the engine 1 changes, since each signal changes, YES (Yes).
And the process moves to step S6. The piston position P is also changed by the change of the crank angle, and when the crank angle changes through the top dead center and the bottom dead center, the compression stroke cylinder is also changed.

In step S6, the ECU 21 calculates a new compression stroke cylinder and piston position P based on the crank angle signal and the TOP signal. In step S8, the ECU 21 calculates the compression stroke cylinder and piston position P stored in the storage device. After updating the information, the process proceeds to step S10. In addition, the crank angle signal and the TOP signal do not change and N
When an O (negative) determination is made, step S1 is performed directly.
Move to 0.

In step S10, it is determined whether an engine start command has been issued. When the starting condition is satisfied during the automatic stop of the engine at the time of waiting for a traffic light or the like, and when the driver does not correspond to any of the cases where the ignition switch 14 is operated by the ST, it is determined as NO and the process proceeds to the step S2. Return. Until the determination in step S10 becomes YES, the processes in steps S2 to S8 are repeated. Then, if the start condition is satisfied or the ST operation of the ignition switch 14 is performed and the determination of YES is made in step S10, the engine temperature T detected by the engine temperature sensor 22 is input in step S12, and The information on the compression stroke cylinder and the piston position P is read.

Next, in step S14, the ECU 21 determines whether the early start control can be executed. That is, as described below, the early start control is a process in which a fuel is injected into a compression stroke cylinder and ignited to immediately cause an initial explosion. In order to realize this, a temperature for vaporizing the fuel is required. And a pressure for successful ignition, for example, when the temperature in the cylinder at the time of starting is low, or when the piston position P is hardly compressed near the top dead center and the temperature rise due to compression cannot be expected. Cannot get the first explosion due to misfire.

Therefore, in step S14, it is determined whether or not the engine is in the ignitable range based on the engine temperature T correlated with the in-cylinder temperature and the piston position P in accordance with the map shown in FIG. As is clear from the figure, the higher the engine temperature T and the lower the piston position P, the higher the probability of entering the ignitable region, and the more secure the ignition by the vaporization of the injected fuel.

Here, when the engine 1 is automatically stopped in response to a signal or the like, the temperature of the engine itself has risen due to the operation up to immediately before, so that the in-cylinder temperature rises sufficiently due to heat transfer from the cylinder wall surface. In addition, as described above, the BTDC 9 has a high probability that the crank angle when the engine is stopped is high.
Because it is located around 0 ° CA, the lower piston position P
Is held in. Therefore, in most cases, the determination in step S14 is YE because
It becomes S.

When the determination in step S14 is NO,
In step S16, normal start control is executed. That is, in the case of automatic starting, cranking is started (ST of the driver).
In the case of starting by operation, it is not necessary because cranking has already been started), and fuel injection and ignition are executed for a cylinder which first reaches the intake stroke after cranking. In this case, the start completion is delayed compared to the early start control started in the compression stroke, but the start is completed earlier than the conventional start after the cylinder discrimination. At this time, the fuel injection amount, the injection timing, and the ignition timing are the same as in the control at the time of starting the normal engine.

As described above, by determining the crank angle from the information on the compression stroke cylinder and the piston position P stored in the storage device, the cylinder discrimination can be omitted. Next, in step S18, it is determined whether or not the engine rotation speed Ne is equal to or higher than a preset complete explosion determination value N0.
In the case of O, it is considered that the start has not been completed yet, and the process returns to step S14 to repeat the process. If the determination in step S18 becomes YES, the process proceeds to step S20.

If the determination in step S14 is YES, early start control is executed in step S22, and fuel injection is performed on the compression stroke cylinder. At this time, the fuel injection amount, the injection timing, and the ignition timing are different from those in the normal start control described above, and are determined as follows. Since the in-cylinder air amount of the compression stroke cylinder differs according to the piston position P and the in-cylinder temperature, the optimal fuel injection amount is determined from a map (not shown) set in advance according to the piston position P and the engine temperature T. Ask for. Similarly, an optimum value for the injection timing is determined according to the piston position P and the engine temperature T. In addition, since ignition is performed immediately after the start of cranking, the ignition timing is set to an optimum value that can effectively convert the initial explosion into the rotation of the engine 1.

Thereafter, if the determination in step S18 is NO and the starting is not completed, the processes in steps S14 and S22 are repeated to perform the same control for the cylinders subsequent to the cylinder which was initially detonated as described above. Execute
However, at this time, since the cranking has already been started and compression is performed from the bottom dead center, the piston position P is set as the bottom dead center. In addition, since the temperature of the air that has stayed in the intake system of the engine 1 and has been increased is sucked into the succeeding cylinder, a considerably high in-cylinder temperature is secured as in the first compression stroke cylinder.

Then, when the start is completed and the determination in step S18 becomes YES, the process proceeds to step S20 and normal engine control is executed. That is, the target average effective pressure Pe
And selecting the compression stroke injection or the intake stroke injection based on the engine rotation speed Ne. For example, when the idle operation is continued, the compression stroke injection is set, and when the acceleration is rapid, the intake stroke injection is set. Control is performed by determining the fuel injection amount, the injection timing, and the ignition timing according to the operating state.

Thereafter, it is determined in step S24 whether an engine stop command has been issued. If the engine stop condition is satisfied when waiting for a traffic light or the like, or if the driver does not turn off the ignition switch 14, the determination is NO and the process returns to step S20. In step S24, if any one of the conditions is satisfied and YE
When the determination at S is made, the fuel injection control and the ignition timing control are stopped at step S26, and the process proceeds to step S28. In step S28, the crank angle signal of the crank angle sensor 23 and the TOP signal of the cam angle sensor 24 are read, and based on those signals, the compression stroke cylinder and the piston position P of the engine 1 immediately before the stop are calculated as in step S6. Then, after storing the information in the storage device in step S30, the routine ends.

In this embodiment, the crank angle sensor 23, the cam angle sensor 24, and the ECU 21 for executing the processing of step S28 function as cylinder discriminating means, and perform the processing of step S30. ECU
21 and the storage device function as the discrimination information holding means, and are used when executing the processing of steps S4 to S8.
CU21 functions as discrimination information updating means, and
The ECU 21 at the time of executing the processing of 22 functions as start control means.

As is apparent from the above description, the starting device for the engine 1 of the present embodiment immediately executes the fuel injection and the ignition for the compression stroke cylinder of the stopped engine, so that the first explosion can be quickly carried out. You can go and start. Moreover, since the information on the compression stroke cylinder and the piston position P (cylinder discrimination information) is stored in the storage device when the engine is stopped, and the start control is performed based on the information, the cylinder discrimination processing is immediately performed without performing the cylinder discrimination processing. Start control can be started, and the time required for the start can be further reduced.

In the normal start control in step S16 as described above, the cylinder discrimination processing can be omitted based on the compression stroke cylinder and the piston position P. In this case, too, the start is advanced by a considerable amount of the cylinder discrimination processing. be able to. As described above, since the starting time is shortened, the starting operation is completed almost instantaneously even when the engine 1 is stopped automatically due to a signal or the like, when the engine 1 is automatically started. As a result, the vehicle can be started quickly, and the commercial value of the idle stop vehicle can be improved.

Further, when the crank angle changes due to the movement of the vehicle or the like while the engine is stopped, the information on the compression stroke cylinder and the piston position P is updated accordingly, so that the start control is always performed based on appropriate information. It can be executed, and starting reliability and the like can be prevented to ensure high reliability. In addition, since the storing and updating of the information on the compression stroke cylinder and the piston position P can be realized by extremely simple control, the above-mentioned effects can be obtained without increasing the manufacturing cost.

Although the description of the embodiment has been completed above, the embodiments of the present invention are not limited to this embodiment. For example,
In the above-described embodiment, the starting device of the direct injection engine 1 used for the idle stop vehicle is embodied. However, the starting device of the direct injection engine used for the normal vehicle or the direct injection engine used for the hybrid vehicle is used. It may be embodied as a starting device. Even in this case, the startability can be improved in a normal vehicle, and in a hybrid vehicle,
In addition, a good acceleration response can be realized by quickly starting the engine during acceleration or the like.

Further, in the above embodiment, the starting device capable of executing the early start control for injecting and igniting the fuel in the compression stroke cylinder is embodied. However, the direct injection engine 1 which does not execute the early start control may be used. It can be embodied, and even in that case, the start can be completed earlier than in the past.

[0036]

As described above, according to the starting apparatus for a direct injection type internal combustion engine of the present invention, the starting control is started immediately without performing the cylinder discriminating process, so that the starting can be completed quickly. it can.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram showing a starting device for a direct injection engine of an embodiment.

FIG. 2 is a flowchart illustrating a main routine executed by an ECU.

FIG. 3 is a flowchart showing a main routine executed by an ECU.

FIG. 4 is an explanatory diagram showing a map for determining an ignitable area.

[Explanation of symbols]

1 engine (internal combustion engine) 21 ECU (cylinder discriminating means, discriminating information holding means,
Start control means) 23 Crank angle sensor (cylinder discriminating means) 24 Cam angle sensor (cylinder discriminating means)

Continued on the front page (72) Inventor: Jun Takemura 5-33-8 Shiba, Minato-ku, Tokyo Inside Mitsubishi Motors Corporation (72) Inventor: Hiromitsu Ando 5-33-8 Shiba, Minato-ku, Tokyo Mitsubishi Motors Corporation In-house F term (reference) 3G301 HA04 JA00 KA01 KA28 LB04 NC01 PC02Z PE01Z PE03Z PE05Z PF01Z PF03Z PF06Z PF07Z

Claims (1)

[Claims] Cylinder discrimination means for performing cylinder discrimination during operation of an internal combustion engine; discrimination information holding means for holding cylinder discrimination information of the cylinder discrimination means while the internal combustion engine is stopped; And a start control means for executing start control based on the cylinder discrimination information held by the discrimination information holding means.