JPH08177537A - Multiple cylinder engine start time control method - Google Patents

Abstract

PURPOSE: To reduce electrical load at the start time and obtain excellent start performance by stopping the fuel injection and ignition of a specific cylinder when battery voltage is the set voltage or less at the time of engine speed being the start judging engine speed or less or a starter switch being turned on. CONSTITUTION: While a start judging means 41b in a CPU 41 judges the start of an engine when a starter switch 57 is on and/or the engine speed N is lower than the start judging engine speed, an injection/-ignition stop judging means 41d monitors whether battery voltage detected by a battery voltage detecting means 41a has become the specific cylinder stop set voltage or less, and in the affirmative case, judges a specific cylinder stop condition to be materialized. In the case of judging the specific cylinder stop condition to be materialized, injection stop to a specific cylinder is instructed to a fuel injection pulse width/ fuel start timing computing-setting means 41e, an ignition stop to the specific cylinder is instructed to an ignition timing/current flowing time computing- setting means 41f.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the start of a multi-cylinder engine for reducing the electric load by stopping fuel injection and ignition in a specific cylinder when the battery voltage at the engine start is equal to or lower than a preset set voltage. Time control method.

[0002]

2. Description of the Related Art As is well known, since a starting torque is large in a cranking operation at the time of starting, a large load is applied to a battery for driving a starter. Moreover, at the time of starting, in addition to driving the starter, the injector and the ignition device are simultaneously energized, resulting in a large amount of power consumption.

In particular, in a cylinder direct injection engine as disclosed in, for example, Japanese Patent Application Laid-Open No. 4-272448,
Since it is necessary to inject a large amount of fuel into the cylinder in a short time, the fuel pressure is set higher than that of a general intake pipe injection type engine, and therefore the injector is accurate and resistant to high pressure. The ability to operate at high speed is required. Therefore, the power consumption of the injector of the cylinder direct injection type engine is larger than that of the normal intake pipe injection type engine, and that much,
The electrical load on the battery also increases.

On the other hand, one of the features of the in-cylinder direct injection type engine is that the fuel consumption is reduced by the stratified charge combustion. In this stratified charge combustion, the fuel injection timing is set near the ignition timing, and the fuel and air near the spark plug are used. It is made to burn, for example, JP-A-4-183922 and JP-A-58-1.
It is disclosed in Japanese Patent No. 78835.

In such stratified combustion, fuel is injected near the ignition timing, and the temperature inside the cylinder does not rise so much, so that the ignition plug is liable to be covered. Therefore, a larger amount of energy is required to ignite the sparks, and the load on the battery increases accordingly.

After starting, the battery load is reduced by the power generation of the alternator or the like. However, if the electric load is large at the time of starting, the cranking speed decreases, and it becomes impossible to obtain good starting performance. This applies not only to the direct injection type cylinder engine but also to a normal intake pipe injection type engine.

[0007] As a countermeasure against this, for example, the actual exploitation Sho 61-1
According to Japanese Patent No. 84840, when the battery voltage during cranking is equal to or lower than a preset set voltage, fuel injection is stopped to reduce an electric load, and a cranking speed is increased to reduce an electric load on a starter. Fuel injection is started when

[0008]

However, stopping the fuel injection at the time of starting takes time until the engine is started, and during that time, the starter continues to be energized, so that the electric power is continuously supplied to the starter. The load is not reduced, and moreover,
If the start fails, the starter must be driven again for a long time, resulting in wasted battery voltage.

The present invention has been made in view of the above circumstances, and is directed to a multi-cylinder engine capable of reducing the electrical load at the time of starting and suppressing a decrease in the rotational speed of the starter to obtain good starting performance. It is intended to provide a starting control method.

[0010]

In order to achieve the above object, a control method at the time of starting a multi-cylinder engine according to the present invention is a multi-cylinder engine in which an injector is provided for each cylinder.
When the engine speed is equal to or lower than the start determination speed or at least one of the starter switches is on and the battery voltage is equal to or lower than a preset set voltage, fuel injection and ignition of a specific cylinder are stopped. To do.
In a preferred aspect, the injector is a cylinder direct injection type.

[0011]

[Operation] In the present invention, it is judged from the engine speed or the state of the starter switch whether or not the engine starting condition is satisfied. When it is judged that the starting condition is satisfied, the battery voltage is detected. When the battery voltage is equal to or lower than the set voltage, fuel injection and ignition of the specific cylinder (odd-numbered cylinder or even-numbered cylinder in the ignition order, etc.) are stopped. Then, the electrical load to the injector and the ignition device of the specific cylinder is stopped, so that the electrical load is reduced and the decrease in the rotation speed of the starter is suppressed. On the other hand, if the battery voltage is equal to or higher than the set voltage even when the starting condition is satisfied, the injectors and ignition devices of all cylinders can be energized.

When the injector is a direct injection type cylinder, the electric power consumption of the injector and the ignition device is large. Therefore, by stopping fuel injection and ignition for a specific cylinder, the electrical load is remarkably reduced.

[0013]

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

FIG. 16 shows an overall outline including a fuel supply system of a direct injection type cylinder engine which is an example of a multi-cylinder engine.

The in-cylinder direct injection type engine (hereinafter simply referred to as "engine") 1 shown in this embodiment is a two-cycle four-cylinder gasoline engine, and a cylinder head 2, a cylinder block 3, and a piston 4 of this engine 1. The ignition plug 7 connected to the secondary side of the ignition coil 6a and the high-pressure injector 8 are exposed to the combustion chamber 5 formed in 1., and the igniter 6b is connected to the primary side of the ignition coil 6a.

A scavenging port 3a and an exhaust port 3b are formed in the cylinder block 3, and a water temperature sensor 9 is provided in a cooling water passage 3c formed in the cylinder block 3.
Is facing. An air supply pipe 10 is attached to the scavenging port 3a.
The air supply pipe 10 is provided with an air cleaner 11 on the upstream side, and a scavenging pump 12 is provided midway.
Is interposed. The scavenging pump 12 is an engine-driven type that is interlocked with the crankshaft 1a, and the operation of the scavenging pump 12 forcibly supplies fresh air to the combustion chamber 5 and scavenges the inside of the combustion chamber 5.

A bypass passage 13 for bypassing the scavenging pump 12 is connected to the air supply pipe 10, and a bypass control valve 15b for controlling the scavenging pressure of the scavenging pump 12 is interposed in the bypass passage 13. It is equipped. In addition, the bypass pipe 13 is provided in the air supply pipe 10.
A throttle valve 15a is disposed upstream of the inflow port of the accelerator pedal 14 for operating the throttle valve 15a, and an accelerator opening sensor 16 for detecting an accelerator opening (= throttle opening) α is connected to the accelerator pedal 14. There is.

Further, the exhaust port 3b is provided with an exhaust rotary valve 17 for controlling the exhaust timing by opening and closing in synchronization with the rotation of the crankshaft 1a. 18 are in communication. Further, a catalytic converter 19 is interposed in the exhaust pipe 18, and a muffler 20 is connected to the downstream end.

As shown in FIG. 17, the crankshaft 1a has a crank rotor 2 for crank angle detection.
1a and a cylinder discrimination crank rotor 21b are axially mounted at a predetermined interval.
A crank angle sensor 22a formed of an electromagnetic pickup or the like and a cylinder discrimination sensor 22b are provided on the outer circumference of 21b so as to have a predetermined gap S therebetween.

As shown in FIG. 18, the crank angle detecting crank rotor 21a is provided with a plurality of crank angle detecting protrusions 21c at positions BTDC.theta.1 to .theta.3 before the top dead center of each cylinder. The engine 1 shown in the present embodiment performs combustion at equal intervals, and the top dead center TDC of each cylinder whose ignition order is # 1 → # 4 → # 3 → # 2 is set every 90 ° CA. The positions of the crank angle detecting protrusions 21c are θ1 = BTDC75 ° CA and θ2 = BTDC45 ° C.
A, θ3 = BTDC15 ° CA, that is, the crank angle detection protrusions 21c are formed on the circumference at an equal pitch of 30 ° CA with the top dead center TDC of each cylinder interposed therebetween.

Further, as shown in FIG. 19, the cylinder discriminating protrusion 21 is provided on the outer periphery of the cylinder discriminating crank rotor 21b.
d is formed. In the present embodiment, three cylinder discrimination projections 21d are formed, and two of the cylinder discrimination projections 21d are the BTDCθ4 before the top dead center of the # 1 cylinder.
It is formed at the position of θ5. Further, another cylinder discrimination projection 21d is formed at the position of BTDC θ6 before the top dead center of the # 3 cylinder. The crank position of each cylinder discrimination protrusion 21d according to the present embodiment is θ4 = BTDC60 ° CA,
θ5 = BTDC30 ° CA, θ6 = BTDC60 ° CA.

Due to the rotation of the crankshaft 1a, the crank angle detecting protrusion 21c of the crank angle detecting crank rotor 21a is positioned opposite to the crank angle sensor 22a, or the cylinder determining protrusion 21d of the cylinder determining crank rotor 21b. Is opposed to the cylinder discrimination sensor 22b, the gap S between the sensors 22a and 22b and the tops of the protrusions 21c and 21d of the crank rotors 21a and 21b is set to, for example, S = 0.8 ± 0.4 (mm). Has been done.

As shown in FIG. 16, the two sensors 22a and 22b are arranged with a predetermined sandwiching angle. However, in FIGS. The corresponding top dead centers of the rotors 21a and 21b are shown in a matched state.

Further, in each of the sensors 22a and 22b,
The detection timings of the protrusions 21c and 21d of the crank rotors 21a and 21b in synchronization with the rotation of the crankshaft 1a, that is, the detection timings of the crank pulse and the cylinder discrimination pulse detected by the sensors 22a and 22b are shown in FIG. As shown in the timing chart of FIG. 25, the cylinder discrimination pulse of BTDCθ4 of the # 1 cylinder (hereinafter,
“Θ4 pulse” is abbreviated as BTDC of # 1 cylinder BTDC θ1 crank pulse (hereinafter abbreviated as “θ1 pulse”) and BTDC
It is interrupted between a crank pulse of θ2 (hereinafter abbreviated as “θ2 pulse”), and a cylinder discrimination pulse of BTDCθ5 (hereinafter abbreviated as “θ5 pulse”) is a θ2 pulse of # 1 cylinder and a crank pulse of BTDCθ3. (Hereafter, "θ3 pulse"
And abbreviated). Furthermore, the BT of the # 3 cylinder
The cylinder discriminating pulse of DC θ6 (hereinafter abbreviated as “θ6 pulse”) is interrupted between the θ1 pulse and the θ2 pulse of the # 3 cylinder. Therefore, the crank pulse after detecting the θ4 pulse and the θ5 pulse by the cylinder discrimination sensor 22b is
It can be determined that it is the θ3 pulse of the # 1 cylinder, and the θ6 pulse is detected by the cylinder discrimination sensor 22b.
Θ2 pulse and θ3 detected by the crank angle sensor 22a
If the cylinder discrimination pulse is not interrupted between the pulse and the pulse, it can be discriminated that the above-mentioned θ3 pulse indicates BTDCθ3 of the # 3 cylinder.

The timing chart in FIG. 24 shows the fuel injection and ignition at the start, and the timing chart in FIG. 25 shows the fuel injection and the ignition after the start. The above-mentioned θ1 pulse becomes a reference crank angle for starting the dwell start timing timer at the start, and becomes a reference crank angle for starting the injection start timing timer after the start. Further, the θ2 pulse becomes the reference crank angle for starting the ignition timing timer after the start. Further, the θ3 pulse becomes the reference crank angle for starting the injection and the reference crank angle for starting the ignition timing timer at the start, and becomes the reference crank angle for starting the dwell start timing timer after the start.

In a 4-cycle 4-cylinder engine, the cylinder discriminating crank rotor 21b is a cam rotor having a cam shaft axially attached, and the cylinder discriminating sensor 22b is
You may make it oppose to this cam rotor.

Next, the structure of the fuel system will be described. A reference numeral 23 in FIG. 16 is a fuel line, a high-pressure fuel pump 28 is provided in the middle of the fuel line 23, and a high-pressure electromagnetic pressure regulator 33 is provided downstream of the high-pressure fuel pump 28. ing. Further, the upstream side of the high-pressure fuel pump 28 in the fuel line 23 is a low-pressure delivery line 2 that delivers fuel from the fuel tank 24.
3a, and a high pressure line 23b that supplies pressure to the high pressure injector 8 by boosting the fuel from the low pressure delivery line 23a is provided between the downstream side of the high pressure fuel pump 28 and the high pressure electromagnetic pressure regulator 33. Further, the downstream side from the high pressure electromagnetic pressure regulator 33 constitutes a low pressure return line 23c.

The high-pressure electromagnetic pressure regulator 33 is a normally open type and controls the valve opening by duty control or current control. In the duty control, the duty ratio is controlled between 0 and 100%. When the duty ratio is ≧ 80%, it is fully closed. In current control, the valve is gradually closed as the control current increases. In the high-pressure electromagnetic pressure regulator 33, the fuel pressure in the high-pressure line 23b is controlled by controlling the fuel relief amount in the high-pressure line 23b, and the fuel amount supplied to the combustion chamber 5 is controlled by the high-pressure injector 8. Accurate measurement is possible by the valve opening time.

The low-pressure delivery line 23a and the low-pressure return line 23c are connected to the fuel bypass passage 23.
d through the fuel bypass passage 23d,
A low pressure diaphragm type pressure regulator 27 for adjusting the fuel pressure of the low pressure delivery line 23a is interposed.

In the low-pressure delivery line 23a, the fuel in the fuel tank 24 is delivered by the feed pump 25, passes through the fuel filter 26, and is regulated by the low-pressure diaphragm type pressure regulator 27. Supply to the pump 28.

The fuel line 23 constitutes a so-called line pressure holding type high pressure injection system. In the high pressure line 23b, the fuel supplied from the low pressure delivery line 23a is pressurized by the high pressure fuel pump 28, and A predetermined high-pressure fuel regulated by the high-pressure electromagnetic pressure regulator 33 is passed through a fuel supply path provided with a high-pressure fuel filter 30, an accumulator 31 for buffering the pulsating pressure, and a fuel pressure sensor 32 for detecting the fuel pressure. The high-pressure injector 8 is supplied.

The high-pressure fuel pump 28 is an engine-driven plunger pump, which has check valves provided at the suction port and the discharge port, respectively, and allows fuel from the low-pressure delivery line 23a to pass when the engine is stopped. .

On the other hand, FIG. 14 shows a control device 40. The control device 40 includes a CPU 41, a ROM 42,
The RAM 43, the backup RAM 44, and the I / O interface 45 are composed of a microcomputer or the like connected to each other via a bus line 46.

Further, the control device 40 includes a constant voltage circuit 4
7, a constant voltage circuit 47 is connected to a battery 49 via a relay contact of an ECU relay 48, and a relay coil of the ECU relay 48 is connected to a battery 49 via an ignition switch 50. There is. The constant voltage circuit 47 stabilizes the voltage of the battery 49 and supplies it to each part of the control device 40 when the ignition switch 50 is turned on and the contact of the ECU relay 48 is closed. Also, the backup R
A battery 49 is directly connected to the AM 44 via the constant voltage circuit 47, and a backup power source is constantly supplied regardless of whether the ignition switch 50 is ON or OFF.

Further, the feed pump 25 is connected to the battery 49 via a relay contact of a feed pump relay 54, and the motor portion provided in the starter 56 is connected to the battery 49 via a contact of a magnet switch. Further, the exciting coil of this magnet switch is connected to the battery 49 via the starter switch 57.

A battery 49 is connected to the input port of the I / O interface 45 to monitor the battery voltage, and the crank angle sensor 22a,
The cylinder discrimination sensor 22b, the accelerator opening sensor 16, the water temperature sensor 9, the fuel pressure sensor 32, and the starter switch 57 are connected.

On the other hand, an igniter 6b for driving the ignition coil 6a is connected to the output port of the I / O interface 45, and a feed pump relay to which power is supplied from the battery 49 via the drive circuit 55. 54 relay coil, high-voltage injector 8 exciting coil, and high-voltage electromagnetic pressure regulator 33
Exciting coil is connected.

Fuel injection control of the control device 40, and
The function of executing the ignition timing control is shown in the functional block diagram of FIG.

The functions of the CPU 41 are as follows: battery voltage detection means 41a, start determination means 41b, rotation speed calculation / crank position determination means 41c, injection / ignition stop determination means 41d, fuel injection pulse width / injection start timing calculation / setting means. 41e and ignition timing / energization time calculation / setting means 41f.

In the battery voltage detecting means 41a, the voltage of the battery 49 is A / D converted and further averaged as necessary to detect the battery voltage VB.

The start determination means 41b determines whether or not the start is started based on the state of the starter switch 57 and the engine speed N. That is, when the starter switch 57 is ON and the engine speed N is lower than the preset start determination speed NST (N≤NST), or when one of these conditions is satisfied, it is determined that the engine is started. In this embodiment, when both conditions are satisfied, it is determined that the engine is started.

Rotational speed calculation / crank position determination means 41c
Then, the engine speed N is calculated from the interval time of the crank pulse detected by the crank angle sensor 22a, and, as described above, the interrupt timing of the cylinder discrimination pulse detected by the cylinder discrimination sensor 22b with respect to this crank pulse. From this, the reference crank angle at the time of fuel injection and ignition is detected, and cylinder discrimination is performed.

In the injection / ignition stop judging means 41d, the battery voltage VB detected by the battery voltage detecting means 41a while the start judging means 41b judges that the battery is started.
Is below a preset specific cylinder stop set voltage VS, and when VB ≦ VS is shown, it is determined that the specific cylinder stop condition is satisfied. When the injection / ignition stop determination means 41d determines that the specific cylinder stop condition is satisfied, the fuel injection pulse width / injection start timing calculation / setting means 41e is instructed to stop injection for the specific cylinder, and the ignition timing / energization time is set. The calculation / setting means 41f is instructed to stop ignition for a specific cylinder.

The fuel injection pulse width / injection start timing calculation / setting means 41e calculates the fuel injection pulse width Ti and the injection start timing for each cylinder. The fuel injection pulse width Ti has a fuel pressure coefficient KS and an invalid injection time TS that are set based on the fuel pressure PS detected by the fuel pressure sensor 32 for the fuel injection amount GFST at the time of starting or the fuel injection amount GF after the starting. Correct with and set.

The fuel injection amount GFST at the time of starting is set on the basis of the cooling water temperature TW detected by the water temperature sensor 9, and the fuel injection amount GF after starting is set at the accelerator opening sensor 16
The fuel injection timer is set on the basis of the accelerator opening (= throttle opening) α detected in step 1 and the engine speed N, and is set in the fuel injection timer of the injection target cylinder. On the other hand, when starting, θ3
The pulse is used as a trigger to output the fuel injection pulse width Ti to the injector drive circuit 55a provided in the drive circuit 55. The injection / ignition stop determination means 41d at the time of starting
When the injection stop is instructed from, it is determined whether the injection target cylinder is a preset specific cylinder, and when the cylinder is the specific cylinder, that is, the injection / ignition stop target cylinder, the fuel injection pulse width Ti Is output as Ti = 0. As a result, when the battery voltage VB at the time of starting is equal to or lower than the specific cylinder stop set voltage VS, the energization of the high pressure injector 8 of the specific cylinder is stopped, so that the power consumption of the battery 49 is suppressed.

On the other hand, the injection start timing after starting is set for each combustion method based on the fuel injection amount GF and the engine speed N, and this injection start timing is set in the injection start timing timer of the injection target cylinder.

This injection start timing timer starts with the .theta.1 pulse as the reference crank angle, and starts the fuel injection timer after the time measurement is completed. Then, while the fuel injection timer is timing, a drive signal is output to the high-pressure injector 8 via the injector drive circuit 55a of the drive circuit 55, and a predetermined metered amount of fuel is injected from the high-pressure injector 8.

In this embodiment, the fuel injection timing is variably set according to the engine load (in this embodiment, the fuel injection amount GF is taken as the engine load), so that the optimum combustion method according to the load is set. I am trying to choose. That is, thinning combustion is selected at extremely low loads, stratified combustion is selected at low and medium loads, and uniform mixed combustion is selected at high loads.

Now, each combustion method adopted in this embodiment will be described.

The uniform mixed combustion is a combustion system in which fuel is injected at an early timing, uniformly mixed in a cylinder, and then ignited. Since the air utilization rate is high, it is suitable for high load operation. The mixture formation and combustion process of this homogeneous mixed combustion will be described based on the fuel injection / ignition timing diagram of FIG. 20 and according to the homogeneous mixed combustion stroke diagram of FIG.

First, the injection start timing I shown in FIG.
JST is set early after the exhaust rotary valve 17 is closed (FIG. 21 (b)). The earlier the injection disclosure timing is, the better. However, when the injection is started earlier than the timing when the exhaust rotary valve 17 closes the exhaust port 3b, the exhaust port 3 is
Since the fuel blows out from b, the injection start timing is set after the exhaust port 3b is closed. Then, after the injection is completed ((b) in the figure), the mixture is compressed and mixed by the rise of the piston 4 to form a homogeneous mixture ((c) in the figure), and ignition is performed at a predetermined ignition advance angle ((d) in the figure). Then, the flame propagates in the combustion chamber 5 and burns ((e) in the same figure).

On the other hand, the stratified charge combustion is a combustion system in which the fuel injection is terminated immediately before ignition and the rear end portion of the fuel spray is ignited, and since only the air around the fuel is used, the fuel amount extremely smaller than the filled air amount. It is suitable for low and medium load operation because stable combustion can be obtained. The combustion process by this stratified charge combustion will be described based on the fuel injection / ignition timing diagram of FIG. 22 and according to the stratified charge stroke diagram of FIG. First,
The injection start timing IJST is set so that the fuel injection ends slightly before the ignition (FIG. 23 (a)), and during the injection, the fuel takes in air and forms a rich air-fuel mixture in the vicinity of the spark plug 7, and around it. A lean mixture is formed in layers (Fig.
(b)). When the rich mixture is ignited after the end of injection ((c) in the figure), the flame ignited in the rich mixture propagates to the surrounding lean mixture and burns the lean mixture (see the figure). (d)).

In the thinned-out combustion method, in a four-cylinder engine or more, the stratified combustion is performed once every three times, and the remaining two times, fuel injection and ignition are cut to stop the cylinders (cylinder deactivation). Suppresses fuel consumption during extremely low loads such as during idling.

The ignition timing / energization time calculation / setting means 41f calculates the ignition timing and the energization time at and after the start for each cylinder. The ignition timing at the time of starting is calculated by adding a preset ignition time to the fuel injection pulse width and using the θ1 pulse as the reference crank angle. Further, the ignition timing after the start is set for each combustion system based on the engine speed N and the fuel injection amount GF, and this ignition timing is set to the ignition timing timer of the cylinder to be ignited with the θ3 pulse as the reference crank angle at the start. After the engine is started, the ignition timing timer of the ignition target cylinder is set using the θ2 pulse as the reference crank angle. The energization time is set based on the battery voltage VB.

It should be noted that, at the time of start-up, when ignition stop is instructed from the injection / ignition stop determination means 41d, it is judged whether or not the cylinder to be ignited is a preset specific cylinder. The energization time of the cylinder is set to a value at which ignition is not substantially performed or 0. And
Calculate the dwell start timing based on this energization time, set this dwell start timing in the dwell start timing timer of the ignition target cylinder with the θ1 pulse as the reference crank angle at the start, and after the start, use the θ3 pulse as the reference crank angle. The dwell start timing timer of the ignition target cylinder is set as the angle.

When the θ1 pulse is detected at the time of starting, the dwell start timing timer is started,
After that, when the θ3 pulse is detected, the ignition timing timer is started. As a result, from the time when the timing of the dwell start timing timer ends until the time of the ignition timing timer ends, the I / O interface 4
An ignition pulse is output to the igniter 6b via the ignition output transistor circuit 45a provided in No. 5, and the igniter 6b energizes the ignition coil 6a of the ignition target cylinder to the primary side. Then, when the timing of the ignition timing timer ends, the ignition plug 7 of the ignition target cylinder is ignited.

Next, fuel injection control and ignition timing control by the control device 40 will be described with reference to the flow charts of FIGS. Each flow chart is executed at a predetermined timing after turning on the ignition switch 50. When the ignition switch 50 is turned on, the system is initialized (all flags and count values in the flow chart are cleared).

The flowchart of FIG. 4 shows a cylinder discrimination and engine speed calculation routine which is interrupted and activated each time a crank pulse is input.

After the ignition switch 50 is turned on, when the crank pulse output from the crank angle sensor 22a is input as the engine rotates, it is determined in step S1 whether the crank pulse input this time is θ1 to θ3. Identification is performed based on the interruption pattern of the cylinder identification pulse from the cylinder identification sensor 22b, and in step S2, the next top dead center TDC is determined from the interruption pattern of the cylinder identification pulse.
Cylinder F # i arriving at is determined.

That is, as shown in the timing charts of FIGS. 24 and 25, in this embodiment, the fuel injection and ignition order is set to # 1 → # 4 → # 3 → # 2, and the θ4 pulse is # 1.
It is interrupted between the above-mentioned θ1 pulse and θ2 pulse, which indicate before the top dead center of the cylinder, and then between the θ2 pulse and the θ3 pulse.
It is set to interrupt 5 pulses.
It is set so that the θ6 pulse is interrupted between the θ1 pulse and the θ2 pulse indicating before the top dead center of the three cylinders.

Therefore, when there is no interruption of the cylinder discriminating pulse between at least the previous crank pulse and the previous crank pulse, and when the cylinder discriminating pulse is interrupted between the previous crank pulse and the present crank pulse. It can be identified that the crank pulse this time is the θ2 pulse.

When the cylinder discrimination pulse is interrupted between the crank pulse of the previous time and the crank pulse of the time before the last time, and the cylinder discrimination pulse is interrupted between the crank pulse of the previous time and the current time, the cylinder discrimination is executed. This crank pulse is # 1
It can be identified that it is the BTDCθ3 pulse of the cylinder. On the other hand, if there is a cylinder discrimination pulse interrupt between the previous and the previous two crank pulses, and there is no cylinder discrimination pulse interrupt between the previous and this crank pulse, the current crank pulse is the BTDCθ3 of the # 3 cylinder. It can be identified as a pulse. As a result, the cylinder F # i reaching the next top dead center TDC can be determined by the input of this θ3 pulse.

Then, in step S3, the pulse input interval time Tθ (see FIG. 25) between the input of the previous crank pulse and the input of the current crank pulse is detected. As shown in FIG. 18, the crank rotor 21
When the protrusions 21c are formed at equal intervals around a, the pulse input interval time Tθ can be set in real time.

Next, in step S4, the engine speed N is calculated from the pulse input interval time Tθ, and the RAM 4
Stored as rotation speed data in a predetermined address of No. 3, and exit the routine. This rotation speed data is 10 msec described later.
A routine that is started every time to make a start determination and a cylinder stop determination (see FIG. 5), a routine that is started every θ2 pulse to set the fuel injection pulse width and injection start timing (see FIG. 1), and every θ2 pulse It is read by a routine (see FIG. 6) that is started at the time of setting the ignition timing and the energization start time.

Next, the start determination / cylinder stop determination routine will be described with reference to the flowchart of FIG. This routine is started by timer interrupt every 10msec,
In step S11, the voltage of the battery 49 is A / D converted,
If necessary, the averaging process is performed and the battery voltage VB is read.

After that, a start determination is made in steps S12 and S13. In this embodiment, when the starter switch 57 is determined to be ON in step S12 and the engine speed N is determined to be equal to or lower than the start determination speed NST (NST = 450 rpm in this embodiment) in step S13, the start is determined. to decide. The start determination may be determined to be a start when the starter switch 57 is ON or the engine speed N is equal to or less than the start determination rotation speed NST. NST can also be set appropriately.

When it is determined that the engine is started in steps S12 and S13 and the process proceeds to step S14, the start determination flag FST is set and the process proceeds to step S15.

In step S15, it is determined whether or not the cylinder is stopped when the engine is started. This cylinder stop determination is made in the above step S11.
The battery voltage VB read in step 3 is compared with the preset specific cylinder stop set voltage VS, and when VB≤VS, it is determined that the cylinder stop condition is satisfied, and the routine proceeds to step S16 to set the cylinder stop flag FCYLST and execute the routine. Get out. The specific cylinder stop set voltage VS is a voltage required to secure the starting torque of the starter 56 at the time of starting the engine and suppress the decrease in the rotation speed.
It is determined in advance from experiments or design, such as setting VS = 6V.

On the other hand, if the starter switch 57 is turned off in step S12, or if it is determined in step S13 that the engine speed N is equal to or higher than the start determination speed NST,
When it is determined that the engine has been started, the process branches to step S17 to clear the startup determination flag FST, clear the cylinder stop flag FCYLST in step S18, and exit the routine. When it is determined in step S15 that the battery voltage VB is equal to or higher than the specific cylinder stop set voltage VS, the process branches to step S18, and the cylinder stop flag FCYLS is determined as described above.
Clear T and exit the routine.

When the start determination flag FST is set, the start time control is executed in the next fuel injection pulse width / injection start timing setting routine and the ignition timing / energization start time setting routine which will be described later, and the cylinder is stopped. When the flag FCYLST is set, the fuel injection and the ignition of the specific cylinder are stopped in the start-up control.

Next, the fuel injection pulse width / injection start timing setting routine will be described with reference to the flowcharts of FIGS. 1 to 3, and then the ignition timing / energization start time setting routine will be described with reference to the flowcharts of FIGS. 6 and 7. explain. Both routines are interrupted by the input of θ2 pulse.When the engine is started, the former fuel injection pulse width / injection start timing setting routine has priority over the latter ignition timing / energization start time setting routine. After the engine is started, the priority is reversed.

In these two routines, the fuel injection pulse width, the injection start timing, and the injection start timing for the cylinder F # (i + 2), which is two cylinders after the cylinder F # i approaching the top dead center TDC, obtained by the cylinder discrimination, The ignition timing and the energization start time are set. As shown in the timing chart of FIG. 24 or FIG. 25, if the injection / ignition sequence is # 1 → # 4 → # 3 → # 2, for example, If the cylinder reaching the dead center TDC is the # 3 cylinder, the # 3 cylinder is activated by the interrupt of the BTDC θ2 pulse before the top dead center, and the calculation result is for the # 1 cylinder.

In step S21, it is determined whether the current engine operating state is during starting or after starting by referring to the value of the starting determination flag FST. This start determination flag FST is the same as the above 1
It is set in a start determination / cylinder stop determination routine (see FIG. 5) executed every 0 msec. When the start determination flag FST is FST = 1, it means that the engine is starting, so the routine proceeds to step S22 and starts. On the other hand, when FST = 0, since it is after the start, the process branches to step S29 to execute the normal time control.

First, the starting control will be described. When it is determined in step S21 that the engine is being started and the process proceeds to step S22, it is determined whether the current injection / ignition target cylinder is the cylinder stopped cylinder (specific cylinder). This cylinder stopped cylinder can be arbitrarily set, and in the present embodiment, the # 2 cylinder and the # 4 cylinder are cylinder stopped cylinders. When the cylinder to be injected / ignited this time is the cylinder stopped cylinder, the process proceeds to step S23, and the value of the cylinder stop flag FCYLST is referred to.

This cylinder stop flag FCYLST is set by the above-mentioned start judgment / cylinder stop judgment routine (see FIG. 5). When FCYLST = 1, the battery voltage VB is low and the cylinder stop condition is satisfied. Then, the process proceeds to step S24, and the fuel injection pulse width Ti [msec] that determines the fuel injection time (injector valve opening time) is set to Ti = 0, and step S
25, the target cylinder for this injection / ignition (from the top dead center T
The fuel injection pulse width Ti is set to the fuel injection timer of the cylinder two cylinders after the DC is reached) and the routine is exited.

As a result, when the battery voltage VB at the time of starting is equal to or lower than the specific cylinder stop set voltage VS, as shown in FIG. 24 (c), the cylinder stop cylinders # 4 and # 2 are respectively faced. The high-voltage injector 8 being operated is not effectively energized, and fuel is not injected. Therefore, the consumption of the battery 49 when the voltage drops is suppressed.

On the other hand, when it is determined in step S22 that the cylinder to be injected / ignited this time is not the cylinder stopped cylinder (# 1 cylinder, # 3 cylinder in this embodiment), or the cylinder is stopped in step S23. When it is determined that the value of the flag FCYLST is FCYLST = 0 at the time of normal starting, the process branches to step S26, and the starting injection amount GFST [g] is interpolated in the table based on the cooling water temperature TW detected by the water temperature sensor 9. Set with reference with calculation. The table is composed of a series of addresses in the ROM 42. In each area, the injection amount for securing the starting performance in the cold state is preliminarily obtained from experiments or the like and stored, and as shown in the step, cooling is performed. The lower the water temperature TW, the higher the starting injection amount GFST is set.

When the starting fuel injection amount GFST is set in step S26, the fuel pressure coefficient based on the fuel pressure PS [kpa] in the high pressure line 23b detected by the fuel pressure sensor 32 in the next step S27. KS and invalid injection time TS [msec] are set by referring to a table stored as data in the ROM 42 with interpolation calculation. As shown in the step, this table shows the fuel pressure P
The fuel pressure coefficient KS and the invalid injection time TS with S as a grid
And are set in advance by experiment or design. The fuel pressure coefficient KS is an injection characteristic of the injector that changes depending on the fuel pressure PS, and the start-time injection amount GFST is corrected according to the fuel pressure PS and the start-time injection amount G is also corrected.
Convert FST [g] into time. Further, the invalid injection time TS changes depending on the fuel pressure PS and the injector 8 for high pressure is used.
It compensates for the operation delay of.

Then, the process proceeds to step S28, the fuel injection pressure coefficient KS is multiplied by the starting injection amount GFST [g], the time is converted, and the invalid injection time TS is added to the value.
The fuel injection pulse width Ti that determines the fuel injection time at the time of starting is calculated, the process returns to step S25, and this fuel injection pulse width Ti is set in the fuel injection timer of the corresponding cylinder, and the routine exits.

As a result, as shown in FIG. 24 (c), the number of fuel injections at the time of battery voltage drop in this embodiment is half that at the time of normal start, and the electric load of the battery 49 is reduced accordingly. To be done.

The fuel injection timer at the time of starting, which is set in step S25, is started by the routine executed every θ3 pulse shown in the flowchart of FIG. 10 (details will be described later).

On the other hand, when the engine start is completed, as shown in FIG.
In step S17 of the start determination / cylinder stop determination routine shown in the flowchart of FIG. 5, the start determination flag FST is cleared. Then, in the above-mentioned fuel injection pulse width / injection start timing setting routine, the process branches from step S21 to step S29, and shifts to normal control.
As described above, when the engine shifts from the starting state to after starting, the priority order of the routine is reversed, and before the fuel injection pulse width / injection start timing setting routine, the ignition timing / energization start time setting described later is set. The routine is executed.

In step S29, a fuel injection pulse width / injection start timing setting subroutine for normal control is executed.

This fuel injection pulse width / injection start timing setting subroutine is executed according to the flow charts shown in FIGS.

First, in step S31, the fuel injection amount GF is set based on the accelerator opening (= throttle opening) α and the engine speed N by referring to the table shown in the step with interpolation calculation. In addition, in this table,
An optimal fuel injection amount GF is stored in advance by experiments or the like according to the accelerator opening α and the engine speed N.

Next, in step S32, the fuel pressure P in the high pressure line 23b detected by the fuel pressure sensor 32 is detected.
Based on S, the fuel pressure coefficient KS and the invalid injection time TS are set. The fuel pressure coefficient KS and the invalid injection time TS
Is set by referring to the table shown in step S27 (see FIG. 1) with interpolation calculation. Then, in step S33, the fuel pressure coefficient KS is added to the fuel injection amount GF.
Is multiplied and converted into time, and the value is added to the invalid injection time TS
Is added to calculate the fuel injection pulse width Ti.

Thereafter, in step S34, the stratified / thinned combustion switching determination value GFS1 is determined based on the engine speed N.
And the uniform mixing / stratified combustion switching determination value GFS2 is set.
The both combustion switching determination values GFS1 and GFS2 are set by referring to the table shown in this step with interpolation calculation. In this table, the engine speed N [rpm] is set as a grid from an experiment or the like in advance. The both combustion switching determination values GFS1 and GFS2 thus obtained are stored.

This stratified / thinned combustion switching determination value GFS1,
The uniform mixed / stratified combustion switching determination value GFS2 is a reference value when switching the combustion mode according to the load of the engine. In this embodiment, the fuel injection amount GF is taken as the engine load, and the combustion mode is also changed. Is a uniform mixed combustion method,
The setting is switched between the stratified combustion method and the stratified combustion and thinning combustion method. That is, when the engine is under high load operation (GF> GFS2), the homogeneous mixed combustion system (Fig. 20, Fig. 2
1) is adopted, and at the time of medium / low load operation (GFS1 <G
F ≦ GFS2), stratified combustion method (see FIGS. 22 and 23), and when operating at extremely low load (GF ≦ GFS2)
1), the thinning combustion method is adopted.

After the stratified / thinned combustion switching determination value GFS1 and the uniform mixing / stratified combustion switching determination value GFS2 are set in step S34, the process proceeds to step S35, where the fuel injection amount GF (= engine load) is obtained. , And the above stratification / thinning combustion switching determination value GFS1 is compared.

For example, in the first routine after the engine is started, the operation is an extremely low load operation in which the engine shifts to idle. Therefore, in step S35, it is determined that GF≤GFS1, and the process proceeds to step S36 to set the combustion method determination flag F1 to 00. Set to. This combustion system discrimination flag F1 is represented by 2-bit data, F1 = 00 represents the thinning combustion system, and F1 =
01 represents the stratified combustion system, and F1 = 10 represents the homogeneous mixed combustion system.

When the combustion method after the engine is started is set to the thinning combustion method of F1 = 00 in step S36, the process proceeds to step S37, and the fuel injection amount G
The injection end timing IJET [msec] (FIG. 25) which determines, based on F and the engine speed N, the temperature at which the fuel injection is terminated before ignition by referring to the table with interpolation calculation
(See (b)). In order to obtain the optimum combustion in the stratified combustion, it is necessary to form a rich air-fuel mixture around the spark plug 7 at the time of ignition (see FIGS. 23 (b) and 23 (c)). You need to manage the intervals. The injection end timing IJET during stratified combustion is experimentally obtained in advance and stored as a table with the fuel injection amount GF and the engine speed N as parameters.

Next, in step S38, the injection start timing IJST is calculated from the following equation.

IJST ← TθM1− (TADV + IJET + Ti) TθM1 is the time from the crank pulse input, which is the reference when setting the injection start timing, to the top dead center TDC of the injection / ignition target cylinder. Then, as shown in the timing chart of FIG. 25, the θ1 pulse input is set as the reference crank angle. When the θ1 pulse input is used as a reference crank angle, the above TθM1 is: TθM1 = 2.5 × Tθ Tθ: latest crank pulse input interval time TADV: ignition advance time conversion value (ignition timing in FIGS. 6 and 7)
It is calculated by the energization start time setting routine).

After that, when the routine proceeds to step S39, it is judged whether the current fuel injection is thinning-out combustion or all-cylinder combustion by referring to the value of the combustion system discrimination flag F1. The combustion method this time is the thinning combustion method (F1 = 00) in step S36.
Therefore, the process proceeds to step S40 and the injection number count value C is referred to. This injection count value C
Is for counting the number of thinned cylinders at the time of combustion, and can be arbitrarily set by the number of cylinders and the thinning interval at the time of combustion. In this embodiment, the stratified charge combustion during thinning combustion is performed once every three times.
Since the fuel injection is set to be performed and the remaining two fuel cuts are set, it is determined in step S40 whether the fuel injection cylinder is the fuel injection cylinder or the fuel injection stop cylinder based on whether the injection number count value C is C = 2 or not.

Since the initial value of the injection number count value C is 0, the first routine after engine start branches to step S41 to set the fuel injection pulse width Ti to 0, and in step S42 the injection number count value. C is counted up, the process returns to step S44, and the injection start timing IJST calculated in step S38 is injected.
The injection start timing timer for the ignition target cylinder is set, the process returns to step S25 (see FIG. 1), the fuel injection pulse width Ti is set for the fuel injection timer for the corresponding injection / ignition target cylinder, and the routine exits. The fuel injection pulse width Ti for the injector 8 of this cylinder this time is Ti = 0.
Therefore, substantially no fuel is injected even if the injection start timing timer times out.

If the extremely low load operation such as the idle operation is continued, the fuel injection pulse width / injection start timing setting subroutine is repeatedly executed at the next routine execution, and the previous injection number count value C is C. = 1
Therefore, the process proceeds from step S40 to step S41, the fuel injection pulse width Ti is set to Ti = 0, the injection number count value C is incremented at step S42, and the process proceeds to step S44. Therefore, this injection
Fuel injection to the ignition target cylinder is also stopped.

On the other hand, when the fuel injection pulse width / injection start timing setting subroutine is repeatedly executed thereafter, since the injection number count value C is C = 2, the process proceeds from step S40 to step S43. The injection number count value C is cleared, and the injection start timing IJ calculated in step S38 is cleared in step S44.
ST is set to the injection start timing timer of the injection / ignition target cylinder, and the process returns to step S25 (see FIG. 1) again, and the fuel injection timer of the corresponding cylinder is set to step S3.
The fuel injection pulse width Ti set in 3 is set, and the routine exits.

As a result, during the extremely low load operation after the engine is started, if the first cylinder stopped cylinder is # 1 cylinder, the fuel injection cylinders are # 3 cylinder, # 4 cylinder, # 1 cylinder, ... Will be set once every. This is shown in the table below.

[0099] → Time ○: Fuel injection cylinder ×: Fuel injection stopped cylinder As described above, in the present embodiment, at the time of thinning combustion, the thinning interval is specified instead of stopping the specific cylinder. Move in sequence, and thus
Even if thinning combustion is performed during extremely low load operation, engine vibration is suppressed and smooth operating characteristics can be obtained.

Then, during normal control after engine start,
In the step S35, the fuel injection amount GF set in the step S31 is compared with the stratified / thinned combustion switching determination value GFS1 set in the step S34.
If it is determined that F> GFS1, the process branches to step S51, where the fuel injection amount GF and the step S34 are performed.
The uniform mixing / stratified combustion switching determination value GFS2 set in step 2 is compared. For example, when the engine load is not so high in normal running and the low and medium load operation of GF≤GFS2, the process proceeds to step S52, the combustion system determination flag F1 is set to the stratified combustion system of F1 = 01, and in step S53, Based on the fuel injection amount GF and the engine speed N, the injection end timing IJET [msec] (see FIG. 25 (b)) is set by referring to the table with interpolation calculation as in step S37. This table may be the same as the table referred to in step S37, or may be another table with different characteristics.

Next, returning to step S38, the injection start timing IJST during stratified charge combustion is calculated (IJST ← T
θM1− (TADV + IJET + Ti)), and in step S39, the value of the combustion system determination flag F1 is referred to. This combustion system discrimination flag F1 is F1 which indicates stratified charge combustion in step S52.
Since it is set to = 01, the process jumps to step S43 to clear the injection number count value C, and then at step S44, the injection start timing IJST at the time of stratified combustion calculated at step S38 is injected / injected into the ignition / ignition target cylinder The start timing timer is set, and the process returns to step S25 shown in FIG.
The fuel injection pulse width Ti set in step S33 is set, and the routine exits.

On the other hand, at the time of routine execution during a transition such as acceleration operation, in step S51, the fuel injection amount GF set in step S31 is compared with the homogeneous mixing / stratified combustion switching determination value GFS2 set in step S34. result,
It is determined that the high load operation of GF> GFS2, step S5.
When the process branches to 4, the combustion system determination flag F1 is set to F1 = 10 indicating the homogeneous combustion system, and step S5
In step 5, the injection start angle IJSa [° CA] before top dead center is determined, which determines the injection start timing by referring to the table with interpolation calculation based on the fuel injection amount GF and engine speed N set in step S31. To do. In the present embodiment, the injection start angle IJSa is set with reference to the top dead center TDC of the injection / ignition target cylinder (see FIG. 25 (c)). In homogeneous mixed combustion, it is desirable to end the fuel injection as early as possible and mix it sufficiently with fresh air. However, if the fuel injection is started earlier than the time when the exhaust port 3b is closed, blow-through of fuel occurs. The fuel injection start timing is managed by the crank angle, and the fuel injection is started early after the exhaust port 3b is closed.

Next, in step S56, the injection start timing IJST corresponding to the injection start angle IJSa [° CA] is calculated from the following equation.

IJST ← TθM2− (Tθ / θs) × IJSa The above TθM2 is the time from the crank pulse input, which is the reference when setting the injection start timing, to the top dead center TDC of the injection / ignition target cylinder. As shown in the timing chart of FIG. 25, in the present embodiment, the θ1 pulse input of one cylinder before is set as the reference crank angle, and it is calculated by TθM2 = 5.5 × Tθ. Further, θs is an angle between crank pulses, which is 30 ° CA in this embodiment. Therefore, by (Tθ / θs) × IJSa, the injection start angle is converted into time from the time per 1 ° CA rotation, and this value is subtracted from the above TθM2 to make the θ1 pulse input one cylinder before the reference crank angle. The injection start timing IJST to be set is set (see FIG. 25 (c)).

Then, returning to step S43, after clearing the injection number count value C, the injection start timing IJST at the time of homogeneous mixed combustion calculated in step S56 is set in the injection start timing timer of the injection / ignition target cylinder in step S44. Set and again step S2 shown in FIG.
Returning to step 5, the fuel injection timer for the corresponding cylinder is set to the fuel injection pulse width Ti set in step S33, and the routine exits.

The injection start timing timer set in step S44 is started by a routine executed for each θ1 pulse input shown in FIG. 8 (details will be described later).

Next, the ignition timing / energization start time setting routine will be described with reference to the flowcharts shown in FIGS. As described above, this routine is executed after the above-mentioned fuel injection pulse width / injection start timing setting routine at the engine start, and after the engine start is executed with priority to this fuel injection pulse width / injection start timing setting routine. To be done.

In step S61, it is determined whether the current engine operating state is at the start or after the start by referring to the value of the start determination flag FST. This start determination flag FST is the same as the above 1
It is set by a routine executed every 0 msec (see FIG. 5), and when the start determination flag FST is FST = 1, it means that the engine is starting. Therefore, the routine proceeds to step S62 to execute the startup control, On the other hand, in the case of FST = 0, since it has been started, the process branches to step S71 and shifts to the normal control.

First, the starting control will be described, and then the normal control will be described.

When it is determined in step S61 that the engine is being started and the routine proceeds to step S62, it is determined whether the cylinder to be injected / ignited this time is the cylinder stopped cylinder. As described above, the cylinder stop cylinders can be set arbitrarily, and in the present embodiment, the # 2 cylinder and the # 4 cylinder when the ignition order is # 1 → # 4 → # 3 → # 2.
The cylinder and the cylinder are referred to as cylinder stop cylinders.

If the cylinder to be injected / ignited this time is the cylinder stopped cylinder, the flow advances to step S63 to refer to the value of the cylinder stop flag FCYLST.

The cylinder stop flag FCYLST is set in the start judgment / cylinder stop judgment routine (see FIG. 5). When FCYLST = 1, the battery voltage VB is low.
Since the cylinder stop condition is satisfied, step S64
Then, the energization time DWL is set by the cylinder deactivation time DWL0, and the routine proceeds to step S66. This cylinder stop energization time DWL
0 is a time during which current is not substantially applied, such as DWL0 = 0 or a minimum time.

On the other hand, if it is determined in step S62 that the cylinder to be injected / ignited this time is the cylinder burning cylinder, or in step S63 FCYLST = 0, that is, the battery voltage VB.
Is in the normal voltage state, the process branches to step S65, and the energization time DWL [mse is determined based on the battery voltage VB.
Set [c] by referring to the table with interpolation calculation. In this table, as the battery voltage VB is higher, the energization time DWL [msec] is set shorter as shown in the step.

When the cylinder to be injected / ignited this time is the cylinder burning cylinder and the energization time DWL is set in step S65, the process proceeds to step S66, and the ignition timing IGt is obtained from the following equation.

IGt ← Ti + IGST IGST: A preset time [msec] from the end of injection to ignition (stored as ROM data) This ignition timing IGt determines how many msec after the end of injection the ignition is performed. , Θ3 pulse is set as the reference crank angle. As shown in FIGS. 24 (b) and 24 (c), since the fuel injection pulse width Ti at the time of starting is started with the θ3 pulse as the reference crank angle, the set time IGST is added to this fuel injection pulse width Ti. To ask.

Then, in step S67, the dwell start timing DWLST is calculated from the following equation.

DWLST ← (TθM3 + IGt) -DWL TθM3: Time from the crank pulse input which is the reference when setting the dwell start timing to the crank pulse input which is the ignition timing setting reference, the timing of FIGS. 24 (b) and 24 (c) As shown in the chart, in this embodiment, the reference crank angle for starting the dwell at the time of starting is θ
One pulse, the reference crank angle when setting the ignition timing is θ3
It has a pulse. Therefore, the interval time of TθM3 can be calculated by TθM3 = 2 × Tθ.

Thereafter, in step S68, the ignition timing IGt is set in the ignition timing timer of the injection / ignition target cylinder, and in step S69, the dwell start timing DWLST is set in the dwell start timing timer of the injection / ignition target cylinder. Exit through.

At the time of starting, the dwell start timing timer of the cylinder burning cylinder set in step S69 is started with the BTDCθ1 pulse before top dead center as the reference crank angle, while the ignition timing timer set in step S68 is started. Is started with the BTDCθ3 pulse before top dead center as the reference crank angle (details will be described later).

On the other hand, in step S62, it is determined that the cylinder to be injected / ignited this time is the cylinder stopped cylinder (# 4 cylinder or # 2 cylinder), and the cylinder stop flag FCYLST is FCYLST = 1 in step S63. When it is determined that the voltage VB has dropped, in step S64, the energization time DWL is set to the cylinder deactivation time energization time DWL0, and steps S66 and S67 are executed.
When I proceed to, Ignition timing IG
Calculate t and dwell start timing DWLST.

Similar to the cylinder burning cylinder, the ignition timing IGt is set in the ignition timing timer of the injection / ignition target cylinder in step S68, and the dwell start timing DWLST is set in the dwell start timing timer in step S69. Exit the routine.

As shown in FIG. 24 (c), the cylinder to be injected / ignited this time when the battery voltage is low is the cylinder stopped cylinder (#
4, # 2), the fuel injection pulse width Ti is Ti = 0.
(See step S24 in FIG. 1)
The ignition timing IGt set in step S66 is IGt ← IGST, while the dwell start timing DWLST is D
If WL = 0, then DWLST ← TθM3 + IGt. Since TθM3 is the interval time between the θ1 pulse and the θ3 pulse, the end timing of the dwell start timing DWLST and the end timing of the ignition timing IGt become the same, and the ignition of the cylinder stopped cylinder is stopped.

On the other hand, when the engine start is completed, as shown in FIG.
In step S17 of the start determination / cylinder stop determination routine shown in the flowchart of FIG. 6, the start determination flag FST is cleared, so the routine branches from step S61 to step S71 of the ignition timing / energization start time setting routine in normal time. Move to control. As described above, when the engine shifts from the start state to the start state, the priority order of the routine is reversed, and this ignition timing / energization start time setting routine is the same as the fuel injection pulse width / injection start timing setting routine described above. Executed before.

When it is determined in step S61 that the engine has been started, and the routine branches to step S71, the advance value ADV [° CA] for setting the ignition timing according to each combustion method is set.
First, the current combustion method is determined by referring to the value of the combustion method determination flag F1. The combustion method determination flag F1 is set according to the engine load in the above-mentioned fuel injection pulse width / injection start timing setting routine, and F1 = 0.
0 represents the thinning combustion system, F1 = 01 represents the stratified combustion system, and F1 = 10 represents the uniform mixed combustion system.

At step S71, if it is determined that the current combustion method is F1 = 00 thinning-out combustion and the process branches to step S72, the value of the injection number count value C is referred to. This injection count value C is the fuel injection pulse width /
It is set in the injection start timing setting subroutine. When C = 0 or C = 1, the routine is directly terminated without calculating the ignition timing and the dwell start timing. Therefore, at this time, since the ignition timing timer and the dwell start timing timer of the corresponding cylinder are not set, the ignition is stopped. After the start, since the ignition timing / energization start time setting routine is started with priority over the fuel injection pulse width / injection start timing setting routine, the injection count value C is the previous count value. Therefore, the injection count value C is C = 0.
Alternatively, when C = 1, injection during the execution of this routine
The cylinder to be ignited becomes a cylinder stopped cylinder.

If it is determined in step S72 that C = 2, the combustion cylinder is selected. Then, the process proceeds to step S73, where the advance value ADV [° CA] is set to the fuel injection amount GF and the engine speed N. Based on, the table is referenced with interpolation calculation and set. At a series of addresses of the ROM 42, in addition to the table for storing the advance angle value ADV at the time of thinning combustion, the advance angle value ADV at the time of stratified charge combustion and uniform mixed combustion described later
Is obtained in advance from an experiment or the like and stored.

Then, in step S73, the advance angle value ADV at the time of thinning combustion is set by referring to the table with interpolation calculation, and then, in step S74, the battery voltage V
Based on B, the energization time DWL is set by referring to the table shown in step S65 with interpolation calculation, and in step S75, the advance value ADV [° CA] is calculated from the time per 1 ° CA.
An ignition advance time conversion value TADV for converting the above into a time is calculated based on the following equation.

TADV ← (Tθ / θs) × ADV Tθ: latest crank pulse input interval time θs: angle between crank pulses (30 ° C. in this embodiment)
A) Thereafter, in step S76, the ignition advance time conversion value T
The ignition timing IGt is calculated from the following formula based on ADV.

IGt ← TθM4−TADV The above TθM4 is the reference of the crank pulse (BTDCθ2 pulse before top dead center of the cylinder to be ignited in the present embodiment) which is a reference when setting the ignition timing [msec]. In this embodiment, the time until reaching the top dead center TDC is shown in FIG.
As shown in the timing chart of No. 5, it is calculated by TθM4 = 1.5 × Tθ.

Then, in step S77, the dwell start timing DWLST is calculated based on the following equation.

DWLST ← TθM5− (DWL + TADV) Here, TθM5 is the ignition from the input of a crank pulse (BTDCθ3 pulse before the top dead center of the cylinder one cylinder before in this embodiment) which serves as a reference when setting the dwell start timing. In the present embodiment, as shown in the timing chart of FIG. 25, TθM5 = 3.5 × Tθ, which is the time required to reach the top dead center TDC of the target cylinder.

Then, returning to step S68, the ignition timing IGt is set in the ignition timing timer of the cylinder to be injected / ignited this time, and the dwell start timing DWLST is set in the dwell start timing timer in step S69 to exit the routine. .

On the other hand, in step S71, it is determined that the present combustion system is the stratified combustion with F1 = 01, and if the process proceeds to step S78, the ignition timing is advanced based on the fuel injection amount GF and the engine speed N. The angle value ADV is set by referring to the table corresponding to stratified charge combustion with interpolation calculation.

Then, in step S74 and subsequent steps, the ignition timing IGt and the dwell start timing DWLST are calculated in the same manner as described above, and the process returns to steps S68 and S69, and the ignition timing timer of the current injection / ignition target cylinder is set in the ignition timing. I
Gt is set, the dwell start timing DWLST is set in the dwell start timing timer in step S69, and the routine exits.

Further, in step S71, it is determined that the present combustion system is the homogeneous mixed combustion of F1 = 10, and if the process proceeds to step S79, the ignition timing of the ignition timing is determined based on the fuel injection amount GF and the engine speed N. The advance value ADV is set by referring to the table corresponding to the uniform mixed combustion with interpolation calculation.

Then, in step S74 and thereafter, the ignition timing IGt and the dwell start timing DWLST are calculated, the process returns to steps S68 and S69, and the ignition timing IGt is set in the ignition timing timer of the cylinder to be injected / ignited this time. In step S69, the dwell start timing DWLST is set in the dwell start timing timer and the routine exits.

As described above, in this embodiment, as shown in the timing chart of FIG. 25, the dwell start timing after the start is all before the top dead center of the cylinder one cylinder before the cylinder to be injected and ignited this time. The timer is started using the BTDCθ3 pulse input as the reference crank angle, and the ignition timing IGt
Is started by using BTDCθ2 before the top dead center of the injection / ignition target cylinder as a reference crank angle.

Next, regarding each routine in which each timer is started by each crank pulse input, based on the flowcharts of FIGS. 8 to 13, fuel injection control and ignition control at the time of starting, and then fuel injection control after the starting are performed. Each ignition control will be described.

First, when the θ1 pulse is input at the time of starting, the dwell start timing timer at start-up / injection start timing timer start routine after start-up shown in the flowchart of FIG. 8 is started.

Then, in step S81, it is determined whether or not the current operating state is at the time of starting by referring to the value of the starting determination flag FST. If it is determined that FST = 1 at the time of starting, the process proceeds to step S82, and the dwell start timing DWL
Start the dwell start timing timer for the ignition target cylinder for which ST is set and exit the routine. as a result,
Timing of the dwell start timing DWLST [msec] set in the dwell start timing timer is started (see FIG. 24).
(See (b)). When the time measurement is completed, the dwell start timing routine shown in the flowchart of FIG. 12 is activated by interruption, and in step S111, the dwell of the cylinder to be ignited this time is set and the routine exits.

Next, when the θ2 pulse is input, the signal shown in FIG.
The post-start ignition timing timer start routine shown in the flowchart of FIG. 11 is started. First, in step S91, the current operating state is F by referring to the value of the start determination flag FST.
When it is determined that the start is ST = 1, the routine is exited.

Then, when the θ3 pulse is input, the signal shown in FIG.
The start-time injection start timer and ignition timing timer / post-start dwell start timing timer start routine shown in the flowchart of 0 are started. First, in step S101,
When it is determined that the current operating state is the start time of FST = 1 with reference to the value of the start determination flag FST, step S10
2, the fuel injection timer of the injection target cylinder at the time of starting is started. Then, the timing of the fuel injection pulse width Ti set in the fuel injection timer is started (FIG. 24 (b)).
During that time, an injection signal is output to the injector 8 of the corresponding cylinder, and the fuel metered in a predetermined amount by this injector 8 is directly injected into the cylinder. Further, when the injection target cylinder at the time of starting is the cylinder stopped cylinder, Ti = 0, so that fuel is not substantially injected (# 4 cylinder, # in FIG. 24C).
See 2 cylinders).

Next, when the routine proceeds to step S103, the ignition timing timer for the cylinder to be ignited is started and the routine is exited. Then, the timing of the ignition timing IGt [msec] set in the ignition timing timer is started (see FIG. 24).
(See (b)). When this time measurement ends, the ignition timing routine shown in the flowchart of FIG. 13 is activated by interruption.

Then, in step S121 of this ignition timing routine, the dwell of the cylinder to be ignited is cut and the routine is exited. As a result, combustion is initiated by spark ignition.

When the cylinder to be ignited at this time is the cylinder stopped cylinder, the ignition is stopped because the timing end timing of the dwell start timing DWLST and the ignition timing IGt are substantially the same as described above.

As a result, in this embodiment, as shown in the timing chart of FIG. 24 (c), when the battery voltage at the time of starting is low, the fuel injection and ignition of the # 2 cylinder and # 4 cylinder are stopped, and the injection is performed. The ignition target cylinders are only the # 1 cylinder and the # 3 cylinder, and the electric load is reduced accordingly.

On the other hand, when the θ1 pulse is input after the start and the routine shown in the flowchart of FIG. 8 is started, it is determined in step S81 that FST = 0 has been started, and the process branches to step S83, where the current Whether or not the combustion method is homogeneous mixed combustion is determined by referring to the value of the combustion method determination flag F1. In the present embodiment, as shown in the timing chart of FIG. 25, in the stratified charge combustion, the injection start timing timer is set to be started by the θ1 pulse input of the BTDC before the top dead center of the injection target cylinder. In the mixed combustion, the injection start timing timer is set to start by the θ1 pulse input of the BTDC before the top dead center of the cylinder immediately before the cylinder to be injected.

In step S83, the currently set combustion method is determined, and the injection / ignition target cylinder for starting the injection start timing timer is determined. When it is determined in step S83 that the combustion is stratified combustion (including thinned combustion) of F1 = 01 or F1 = 00, the process proceeds to step S84, and the injection target cylinder is the F # i cylinder, that is, the top dead center TDC from now on. It is determined that the cylinder is approaching, and in step S85, the injection start timing timer for the F # i cylinder, which is the injection target cylinder, is started. As shown in FIG. 25, for example, when the injection / ignition target cylinder during stratified combustion is the # 1 cylinder, the injection start timing timer is started by the BTDC θ1 pulse input before the top dead center of the # 1 cylinder.

When the timing of the injection start timing IJST [msec] set in the injection start timing timer is finished, the injection start timing routine shown in the flowchart of FIG.
At 31, the fuel injection timer is started, and while the fuel injection pulse width Ti set in the fuel injection timer is being timed, an injection signal is output to the injector 8 of the corresponding cylinder to inject fuel.

On the other hand, in step S83, if it is determined that the current combustion method is homogeneous mixed combustion of F1 = 10 and the process proceeds to step S86, the cylinder F # (i to be the injection target cylinder of this time is
+1) is determined, and in step S87, the injection start timing timer for the cylinder F # (i + 1) is started, and the routine exits. Then, the injection start timing IJST set in the injection start timing timer of the cylinder F # (i + 1) is timed, and when this time measurement ends, the injection start timing routine shown in the flowchart of FIG. 11 is interrupted and activated.

Then, in step S131 of this injection start timing routine, the fuel injection timer is started, and while the fuel injection pulse width Ti set in this fuel injection timer is being measured, the cylinder F # (i The injection signal is output to the injector 8 of +1) and fuel is injected.
As shown in the timing chart of FIG.
Assuming that the cylinder is the cylinder F # i which is about to reach the top dead center TDC, the routine started by the θ1 pulse input this time is
The # 1 cylinder that is one after that is designated as the injection target cylinder F # (i + 1).

On the other hand, in the ignition system control after starting, as shown in the timing chart of FIG. 25, the dwell start timing DWLST is clocked by the BTDCθ3 pulse input before the top dead center of the cylinder immediately before the ignition target cylinder. As described above, the routine that is started by interruption by the θ3 pulse input shown in the flowchart of FIG. 10 will be described first.

When the θ3 pulse is input, the routine shown in the flowchart of FIG. 10 is started. First, in step S101, it is determined that the current operating state is after the start with FST = 0, and the process branches to step S104. The dwell start timing timer of the ignition target cylinder is started, and the routine is exited.

Then, the timing of the dwell start timing DWLST set in the dwell start timing timer is started, and when this timing is finished, the dwell start timing routine shown in the flowchart of FIG. 12 is activated by interruption. Then, in step S111 of this dwell start timing routine, the dwell of the cylinder to be ignited this time is set and the routine exits.

Thereafter, when the θ2 pulse is input and the ignition timing timer start routine shown in FIG. 9 is activated by interruption, the value of the start determination flag FST is referred to in step S91, and the current operating state is FST = 0. If it is determined that the ignition timing timer for the ignition target cylinder is started, the routine exits from step S92. Then, the ignition timing IGt [msec] set in this ignition timing timer
Is counted, and at the end of the timing, the ignition timing routine shown in the flowchart of FIG. 13 is interrupted, and in step S121, the dwell of the cylinder to be ignited is cut and the routine is exited.

As a result, as shown in the timing chart of FIG. 25, BTDCθ before the top dead center of the cylinder after the start is started.
Ignition is performed at an ignition timing IGt [msec] with 2 pulses as the reference crank angle.

As described above, in the present embodiment, when the battery voltage VB at the time of starting is lowered, as shown in the timing chart of FIG. Since the cylinders are stopped every other time, the electric load at the time of starting is reduced, and accordingly, the decrease in the rotation speed of the starter 56 is suppressed, and good starting performance can be obtained.

The present invention is not limited to the above-described embodiment, and for example, the target engine is not limited to the cylinder direct injection type engine, but may be a normal intake pipe injection type engine.

[0159]

As described above, according to the present invention,
When at least one of the engine speed below the start judgment speed or the starter switch is satisfied and the battery voltage is below the preset voltage, the fuel injection and ignition of the specific cylinder are stopped. Since the electric load at the time of starting is reduced, it is possible to suppress a decrease in the rotation speed of the starter and obtain good starting performance even when the battery voltage is decreasing.

Further, as described in claim 2, when the injector is a direct injection type cylinder, the driving voltage for the injector and the ignition system is high, so that the electric load is stopped by stopping the fuel injection and ignition of the specific cylinder. It can be significantly reduced.

[Brief description of drawings]

FIG. 1 is a flowchart showing a fuel injection pulse width / injection start timing setting routine.

FIG. 2 is a flowchart showing a subroutine for setting a fuel injection pulse width / injection start timing.

FIG. 3 is a flowchart showing a fuel injection pulse width / injection start timing setting subroutine (continued)

FIG. 4 is a flowchart showing a cylinder discrimination / engine speed calculation routine.

FIG. 5 is a flowchart showing a start determination / cylinder stop determination routine.

FIG. 6 is a flowchart showing an ignition timing / energization start time setting routine.

FIG. 7 is a flowchart showing an ignition timing / energization start time setting routine (continued)

FIG. 8 is a flowchart showing a start dwell start timing timer / post-start injection start timing timer start routine.

FIG. 9 is a flowchart showing an ignition timing timer start routine after starting.

FIG. 10 is a flowchart showing a start-up injection start timer, an ignition timing timer, and a post-start dwell start timing timer start routine.

FIG. 11 is a flowchart showing an injection start timing routine.

FIG. 12 is a flowchart showing a dwell start timing routine.

FIG. 13 is a flowchart showing an ignition timing routine.

FIG. 14 is a circuit configuration diagram of a control device.

FIG. 15 is a functional block diagram of a control device

FIG. 16 is an overall schematic view of an in-cylinder direct injection engine.

FIG. 17 is a side view of a crank angle detecting crank rotor axially attached to a crank shaft, a cylinder discriminating crank rotor, and a sensor provided in opposition thereto.

FIG. 18 is a front view of a crank angle detecting crank rotor and a crank angle sensor that is provided opposite to the crank rotor.

FIG. 19 is a front view of a cylinder discrimination crank rotor and a cylinder discrimination sensor opposite to the crank rotor.

FIG. 20 is a timing chart of fuel injection and ignition at the time of homogeneous mixed combustion.

FIG. 21: Stroke diagram during uniform mixed combustion

FIG. 22 is a fuel injection and ignition timing diagram during stratified combustion.

FIG. 23: Stroke diagram during stratified combustion

FIG. 24 is a timing chart showing fuel injection and ignition at startup.

FIG. 25 is a timing chart showing fuel injection and ignition after starting.

[Explanation of symbols]

 1 In-cylinder direct injection engine (multi-cylinder engine) 8 Injector 40 Control device 57 Starter switch N Engine speed NST Start judgment speed VB Battery voltage VS Set voltage

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display area F02P 11/04 302 A

Claims (2)

[Claims] 1. In a multi-cylinder engine in which an injector is provided for each cylinder, at least one of an engine speed equal to or lower than a start determination speed or a starter switch is satisfied, and a battery voltage is set to a preset voltage. A control method at the time of starting a multi-cylinder engine characterized by stopping fuel injection and ignition of a specific cylinder in the following cases. 2. The method of starting control of a multi-cylinder engine according to claim 1, wherein the injector is a direct injection type cylinder.