JP3525689B2 - Fuel injection device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection device for controlling the injection drive of an injection valve provided for each cylinder of an internal combustion engine, and more particularly, a fuel injection device for independently controlling the injection valve of each cylinder. Regarding

[0002]

2. Description of the Related Art Conventionally, injection control is performed for each cylinder independently in order to improve engine output and output control response, but for this purpose, cylinder discrimination is essential. However, the air load determination of the engine is performed by a reference position sensor that outputs a pulse (reference signal) once for one rotation of the cam shaft (two rotations of the engine) attached to the cam shaft and a predetermined angle ( For example, it is performed according to each signal from a crank angle sensor that outputs a pulse (crank angle signal) every 30 ° CA (crank angle). However, the above-described cylinder discrimination method requires a sensor for the cam shaft as well as the crank shaft, which complicates the configuration and increases the cost. Therefore,
Cylinder discrimination is not performed only by the direct-mounted crank angle sensor, all-cylinder simultaneous injection control is performed, or group injection control is performed, or all-cylinder simultaneous injection control or group injection control is tentatively performed, and a predetermined interval is provided during that period. It is common to shift to the independent injection control after performing the cylinder discrimination processing.

For example, in the 4-cylinder simultaneous injection control, FIG.
As shown in (a), a specific pulse position signal (shown as BTDC 5 °) for identifying that one of the first and fourth cylinders as the specific cylinder is the compression top dead center and the other is the exhaust top dead center. It is assumed that the crank angle sensor outputs the signal every 360 ° of the engine, and the four-cylinder simultaneous injection is performed at every other timing of this signal. In this case, four-cylinder simultaneous injection is performed at the position indicated by the symbol ◯ in the stroke phase, and each cylinder sucks the injected fuel into the intake port in one intake stroke (shown as intake) once per 720 ° rotation. Become. Therefore, for example, even if the acceleration command is input with the code a, the fuel injection with the acceleration increase correction is delayed for each cylinder by 720 ° or more.

On the other hand, in the 4-cylinder group injection control, for example, a 1-, 4-cylinder group, and a 3-, 2-cylinder group in which the compression top dead center and the exhaust top dead center coincide with each other. In this state, the crank angle sensor
Singular pulse position signal every 0 ° (BTDC in FIG. 11B)
(Refer to 75 °) is output accordingly, injection of ½ fuel amount during independent injection (indicated by symbol Δ in FIG. 11 (b)) is performed to the 1st and 4th cylinders as the specific cylinders. , The other 3,
Even in the two-cylinder group, the fuel injection amount of 1/2 of the independent injection is performed every 360 ° of the engine while keeping the deviation of 180 °. As a result, fuel injection in the exhaust stroke, which is advantageous in terms of control responsiveness, can be performed with a probability of 1/2 for each cylinder, and control responsiveness can be ensured.

Japanese Patent Laid-Open No. 6-2130052 discloses a fuel injection device for a four-cycle engine in which the six-cylinder group injection control is performed as a temporary control and then the individual cylinder independent injection control is performed.

[0006]

As described above, when the cylinders are not discriminated only by the crank angle sensor and the simultaneous injection control of all cylinders is performed, the structure can be simplified and the cost can be reduced. However, the acceleration is actually performed in response to the acceleration command a. There is a problem that the fuel injection after the increase correction is greatly delayed and the control response is deteriorated. Moreover, in the case of all cylinders simultaneous injection control, the fuel pulsation becomes large, and the fuel pressure decreases in the specific operation range. There may be a problem that the fuel injection amount becomes insufficient.

On the other hand, in the case where the cylinder injection is not discriminated by only the crank angle sensor and the group injection control is performed, the fuel injection in the exhaust stroke, which is advantageous in terms of control responsiveness, is 1 for each cylinder.
/ 2 can be established, and the control response can be improved as compared with the simultaneous injection control for all cylinders. However, in this case, the fuel injection amount at the time of group injection is divided into two injections of every 360 ° in each cylinder so that the fuel injection amount is divided into two injections every 360 °, so that the fuel injection amount is changed when the injection is switched to the independent injection. It is necessary to control to double the number of injections and to switch to once injection at 720 °, and the control at the time of switching tends to be complicated. In particular, the fuel injection valve used here has a large increase / decrease region of the injection amount, and in this respect, the cost tends to increase.

Therefore, an object of the present invention is to improve the control response even when fuel injection is performed only based on the rotation angle signal of the crankshaft, and to simplify the control and reduce the cost of the device. To provide.

[0009]

According to the invention as set forth in claim 1, a plurality of cylinders having four or more cylinders are identified by the identifying means.
A signal for identifying a specific cylinder based on the rotation angle of the crankshaft of the internal combustion engine is output once per rotation, and based on the output, the order of the combustion strokes performed independently by each cylinder is the reverse order. By injecting and driving the injection valve of each cylinder, it is possible to surely perform fuel injection in the exhaust stroke, which is advantageous in terms of control responsiveness, in half of all the cylinders. As described above, even if the cylinders are not identified, the specific cylinders are identified once per one rotation, and the injection valves of the respective cylinders are injection-driven in the order opposite to the order of the combustion stroke.
The control responsiveness of the cylinder can be improved, that is, even if an acceleration or deceleration operation by an accelerator operation or a brake operation is performed, proper fuel injection that follows this operation is performed with good responsiveness, and this internal combustion engine as a whole it is possible to improve the control response of, moreover, Ru results in low cost simplified and device control.

According to the invention described in claim 2, in the fuel injection device according to claim 1, in particular, the cylinder discriminating means discriminates the stroke phase of the cylinder in the internal combustion engine based on the output of the discriminating means. The fuel injection control may be performed in the reverse order of the combustion stroke before the cylinder discrimination is made, and the fuel injection control may be performed in the same order as the combustion stroke after the cylinder discrimination is completed. As described above, even when the cylinder discriminating means is provided, it is possible to prevent the deterioration of the control responsiveness before the cylinder discrimination, that is, even if the acceleration or deceleration operation by the accelerator operation or the brake operation before the cylinder discrimination is performed, the operation is followed. The appropriate fuel injection can be performed accurately.

[0011]

FIG. 1 shows a fuel injection device as an embodiment of the present invention. This fuel injector is in series 4
It is mounted on a cylinder port injection type internal combustion engine (hereinafter simply referred to as engine) E and is mounted on a vehicle (not shown). In the main body 1 of the engine E, the combustion chambers 2 are sequentially arranged in series along the longitudinal direction of the main body. Intake and exhaust valves (not shown) are provided in each combustion chamber 2, and an intake valve is provided in each combustion chamber 2.
And the intake port 3 are opened and closed, and the exhaust valve opens and closes the combustion chamber 2 and the exhaust port 4. Each intake port 3 is connected to an intake passage R including an intake branch pipe 13, a surge tank 14, an intake pipe 15, and an air cleaner (not shown). A throttle valve 16 is provided inside the intake pipe 15, and a throttle opening sensor 18 that outputs a throttle opening signal θ _S is attached to the throttle valve 16.

A fuel injection valve 5 is provided in the intake port 3 of each cylinder, and each valve is connected to a high pressure fuel pipe 6. The high-pressure fuel pipe 6 adjusts the fuel from the fuel supply source 7 to a constant pressure by the fuel pressure adjusting means 8 and supplies the fuel to each fuel injection valve 5. The fuel injection valve 5 injects fuel into the opposing cylinder, and includes an electromagnetic solenoid 9 inside the housing. Here, the electromagnetic solenoid 9 is connected to an engine control unit (hereinafter simply referred to as an ECU) 10 as a driving means via a driver 11, holds a needle valve (not shown) in a closed state when off, and a fuel from the high pressure fuel pipe 6 is held. Is returned to the fuel supply source 7 through the low pressure passage 12, and when not turned on, a needle valve (not shown) is lifted to inject the fuel in the high pressure fuel pipe 6 into the intake port 3. The fuel supply source 7 is composed of a fuel pump (not shown), receives the rotational force of the engine via a rotation transmission system (not shown), and drives it to increase the pressure of fuel from a fuel tank (not shown) and supply it to the high-pressure fuel pipe 6.

A spark plug 19 for igniting each cylinder is mounted on the engine body 1 of FIG. 1, and in particular, the exhaust top dead center and the compression top dead center are in a stroke phase relationship with a shift of 360 °.
Both plugs 19 of cylinder # 1 and fourth cylinder # 4 are connected together and connected to an igniter 20 as a single ignition drive means, and both plugs 19 of second cylinder # 2 and third cylinder # 3 are connected together. Igniter 21 as a single ignition drive means
Connected to. Both igniters 20 and 21 are connected to the ECU 10. Here, in the normal operation mode, the first
Cylinders # 1 and # 4, which are a group of, and cylinders # 2 and # 3, which are a second group, maintain an interval of a crank angle of 180 ° and alternately perform group ignition at a target ignition timing ψt to perform a cylinder deactivation operation. In the mode, the first group of cylinders # 1 and # 4
Group ignition is performed at the target ignition timing ψt with a crank angle of 360 °.

The ECU 10 includes a control circuit 101 and a memory circuit 1.
02, an input / output circuit 103, a power supply circuit (not shown), and the like. The output circuit 103 of the ECU 10, the intake air temperature Ta information outputting the intake air temperature sensor 22, air flow sensor 23 for outputting the amount of intake air A information, water temperature sensor 24 for detecting a cooling water temperature T _W of the warm-up temperature of the engine, A negative pressure sensor 17 for detecting the intake manifold pressure Pint and an engine rotation sensor 27 for detecting the engine speed Ne are connected to each other.

Further, the input / output circuit 103 is provided with a crank angle detection unit s1 for outputting a crank angle signal dθ for each unit angle, for example, every 30 °, and as shown in FIG. And a crank angle sensor 26 including a pulse detection unit s2 that outputs a pulse signal δ that switches in the above mode. The crank angle sensor 26 includes a rotor 261 (see FIG. 2) directly attached to the crank shaft. In particular, the pulse signal δ from the pulse detector s2 of the crank angle sensor 26 is Hi, depending on the shape of the rotor 261,
Switching to Lo, and based on this pulse signal δ, detection processing of a specific pulse position signal δ0 described later is performed, and the signal δ0 is detected.
At the time of detection, one of the first cylinder # 1 and the fourth cylinder # 4 as the specific cylinders is in the stroke phase of 5 ° before exhaust top dead center (BTDC5 °) and the other is 5 ° before compression top dead center (BTDC5 °). It is set to be located at the peculiar position c0 (see FIG. 4).

In the memory circuit 102, programs for main control processing, specific pulse position detection processing, fuel injection / ignition control processing and reference position detection processing shown in FIGS. It is processed. The ECU 10 here has an engine control function,
In particular, as shown in FIG. 2, it functions as an identifying unit A1, a cylinder identifying unit A2, and a control unit A3. Identification means A
1 is a peculiar pulse position signal δ every 360 ° according to the crank angle signal dθ of the crankshaft of the internal combustion engine and the pulse signal δ.
0 is detected, and based on these, a specific cylinder (here, the first,
Singular position in the stroke phase of the cylinder group consisting of the fourth cylinder (here, one of the first and fourth cylinders is located at 5 ° before compression top dead center and the other is located at 5 ° before exhaust top dead center) c0 (See FIG. 4).

Prior to this cylinder discrimination, the cylinder discriminating means A2 performs a fuel cut operation on the other cylinders (here, the second to fourth cylinders) except one of the specific cylinders (here, the first cylinder # 1), In that operating range, the output of the identification means A1, that is,
The singular pulse position signal δ0 for every 360 ° is fetched, the rotational speed Ne1 of the crankshaft at the singular position c0 recognized by the signal is fetched, the fluctuation state thereof is calculated, and then the first cylinder is determined according to the fluctuation state. The reference position c0 (b) of 5 ° before compression top dead center every 720 ° of # 1 is recognized from the reference position signal δ0 (b), and the stroke phases of the other cylinders are discriminated accordingly.

Before the cylinder discriminating means A2 discriminates the stroke phase of each cylinder such as the reference position c0 (b) of the first cylinder # 1, the control means A3 determines the order of the combustion stroke of each cylinder (see FIG. 5). The fuel injection (symbol ∇ in FIG. 5) control is performed in the reverse order (the order along the arrow N in FIG. 5) from the order along the arrow M, and the same as the combustion stroke after the cylinder discrimination is completed. Sequence (arrow M in FIG. 5
Functioning to control the fuel injection (reference numeral ▼ in FIG. 5) in the order according to FIG. At this time, the control means A3 basically controls each fuel injection valve 5 based on each information of the engine speed Ne, the intake air amount A, the throttle opening signal θ _{S, the} crank angle signal dθ, and the pulse signal δ. The drive signal t (#n) for injecting is calculated and output to each driver 11. Each driver 11 sets the internal timer so that the fuel injection valve 5 is opened and closed during the period corresponding to the drive signal t (#n).

The operation of the fuel injection device will now be described with reference to FIGS.
The control program shown in FIG. 0 and the phase stroke diagram of all cylinders in FIG. 5 will be described. When the main switch is turned on, the ECU 10 starts driving, and at the same time cranking is performed. Further, in step s2, each flag F
LG and each timer are set to the initial state, and it is determined in step s3 whether the peculiar pulse position detection flag δ0FLG is on. If it is off, step s4 is on;
Go to 6. Here, in step s4, detection processing of the specific pulse position signal δ0 is started. As shown in FIG. 8, the fuel injection and ignition processes are not performed in the detection process of the specific pulse position δ0, and the pulse detection unit s of the crank angle sensor 26 is in the meantime.
The peculiar pulse position signal δ0 for every 360 ° is detected according to the pulse signal δ from 2.

When step a1 is reached here, it is determined whether the singular pulse position detection flag δ0FLG is on or not. If it is on, the routine returns to the main routine, and if it is off, the routine proceeds to step a2. Here, the pulse position count number n is set to 0, the pulse signal δ is fetched in step a3, and this is H
Waiting for the i level to be reached, and when the Hi level (see FIG. 3) is reached, the process proceeds to steps a4 and a5 in order to replace the current pulse position count number n with n + 1, that is, at first (0 + 1) (n = 1) and the counter CUT1 is started. At steps a6 and a7, the pulse signal δ
Is waited until it becomes the Lo level, and when it becomes the Lo level (see FIG. 3), the value of the counter CUT1, that is, the time width TH (n) of the Hi level is set, and then the counter CUT2 is started. At steps a8 and a9, the pulse signal δ is fetched, waits for it to reach the Hi level again, and when it reaches the Hi level, the counter CUT2
Value, that is, the time width TL (n) of the Lo level is set, and then the pulse position count number n, first, the respective values TH (n) and TL (n) of the counters CUT1 and CUT2 at (n = 1) are set. Capture and proceed to step a10. Here, until the pulse position count number n becomes (n = 3), step a4
Through step a10, the values of the counters CUT1 and CUT2 for n = 1, 2 and 3 are sequentially set and fetched as TH (n) and TL (n). After that, when step a11 is reached, each value TH (n), TL at n = 1, 2, 3
Substituting (n) into the following equation (1), the calculated values a1, a2, a3
Are sequentially requested.

TH (n) / {TH (n) + TL (n)} = a (n) (1) Here, the pulse signal δ from the specific pulse detection unit s2 is
Depending on the pattern of the rotor 261 shown in FIG. 2, Hi, Lo
Since it is preset to change the level, that is,
The time ratio for each Hi and Lo level change can be calculated by the equation (1).

Next, at step a12, 3 of the pulse signal δ repeated every one rotation (360 °) of the crankshaft.
Time ratios a1, a2, a for each Hi and Lo level change
3 is compared with thresholds 0,25. That is, the pattern of the rotor 261 is set as shown in FIG. 3 on the crank angle (deg) axis, and the time ratios a1, a2, and the pulse signal δ obtained from this for each three Hi, Lo level changes.
Basically, a3 is calculated as shown in the following equations (2) to (4).

A (1) = TH (1) / {TH (1) + TL (1)} = 30/60 = 0.5 (2) a (2) = TH (2) /{TH(2)+TL(2)}=20/130=0.15...(3) a (3) = TH (3) / {TH (3) + TL (3)} = 70 /180=0.39...(4) Among these, the time ratio below the preset threshold value 0.25 is determined from within a1, a2, and a3, that is, a2 is determined in this case, and The Hi and Lo level change portion of the detected pulse signal δ is determined as the peculiar pulse position signal δ0. That is, when the specific pulse position signal δ0 is detected, the specific cylinders (the first cylinder # 1 and the fourth cylinder # 4), which are in a relationship of being shifted from each other by 360 °, have specific positions c0 in the stroke phase (see FIG. 4). ), Here, the specific cylinder is set to be located 5 ° before exhaust top dead center and 5 ° before compression top dead center (BTDC 5 °), and this state can be recognized by detection of the specific pulse position signal δ0. Becomes If there is not only one time ratio value that is less than the threshold value 0.25 in step a12, it is determined that the detection is erroneous, and steps a1 to a12 are repeated again.

After that, when step a13 is reached, here, the count processing of the crank rotation angle counter CCUT is started based on the recognized specific pulse position signal δ0,
That is, the counting process of the crank angle signal dθ is started, the specific pulse position detection flag δ0FLG is turned on in step a14, and the process returns to the main routine.

When step s5 of the main routine is reached, it is determined here whether or not the peculiar pulse position detection flag δ0FLG is on. If it is off, the process returns to the peculiar pulse position detection processing of steps s3 and s4, and if it is on, the process proceeds to step s6. Here, it is determined whether or not the distinguishable flag MFLG is on, and if it is on, it is step s12, and if it is off, it is step s7.
Proceed to. After step s7, it is judged whether or not the current operation range satisfies the cylinder identification condition, that is, if not identified, the sequence proceeds to steps s7, 8 and 9. Here, it is determined whether or not the throttle opening θs as a fully closed fuel cut condition is zero, the vehicle speed is equal to or higher than a set speed, and the condition is 2000 when the current engine speed is 1500 RPM or more.
It is determined whether or not it is less than or equal to RPM, that is, whether or not the vehicle is running normally, and further, the intake manifold pressure Pint is a set value (for example, 260
Or it is set to 210 mmHg) or not,
That is, it is determined that the engine is not in an excessive engine braking state, the process reaches step s10, the identifiable flag MFLG is turned on, the other processing of step s12 is performed, the control of this time is ended, and the process returns to step s3. If the current operating range does not satisfy the cylinder identification condition, step s
Steps s11 are reached from 7, 8, and 9, the identifiable flag MFLG is turned off, and the process proceeds to other steps of step s12.

When the crank angle signal dθ is input during the main routine, the fuel injection and ignition control routine of FIG. 9 and the reference position determination routine of FIG. 10 are sequentially executed. When step b1 of the fuel injection and ignition control routine of FIG. 9 is reached, the singular pulse position detection flag δ0FLG is returned to the main routine unless it is on, and if it is on, the routine proceeds to step b2, where the crank rotation angle counter CCU is reached.
The value of T is added by "1" and updated. In step b3,
It is determined whether or not the latest peculiar pulse position signal δ0 is input. If it is not at that timing, the process returns to the main routine, and if the peculiar pulse position signal δ0 is input this time, the process proceeds to step b4.

In step b4, the cylinder determination completion flag NF is set.
If LG is not on, the process proceeds to step b5. Here, it is determined whether or not the distinguishable flag MFLG is on, and if not, the process proceeds to steps b6, 7 and 8. Here, the current operation range does not satisfy the cylinder identification condition, and before the engine is operated in the independent injection mode, the injection control is performed in the cylinder-by-cylinder reverse forward injection mode which is the provisional mode, and then the group ignition in the normal operation mode is performed. Processing is performed to clear the peculiar pulse position detection flag δ0FLG, and the process returns to the main routine.

That is, here, with reference to the latest peculiar pulse position signal δ0, the second cylinder # 2, the fourth cylinder # 4, and the third cylinder # 4.
The drive signal t (#) of each cylinder is controlled so that each cylinder independently performs fuel injection control in the order of the cylinder # 3 and the first cylinder # 1.
n) is calculated and output to the driver 11. At this time, the reference fuel injection amount is calculated from the engine speed Ne and the intake air amount A, and the intake air temperature Ta and the cooling water temperature T are calculated.
Each intake air amount correction coefficient corresponding to _W , intake manifold pressure Pint, etc. is calculated by a correction coefficient map (not shown),
Correct the reference fuel injection amount with each of these intake air amount correction factors,
The current fuel injection amount is calculated. Each driver 11 opens the fuel injection valve 5 during the period corresponding to the drive signal t (#n) and closes the internal fuel injection valve 5 by the internal timers IJTIM1 and IJ.
Since TIM3, IJTIM4, and IJTIM2 are set, injection is performed at the position in the stroke phase indicated by the symbol ∇ in FIG.

In this case, the injection process is performed in the reverse order (the order along the arrow N in FIG. 5) to the order of the combustion strokes (the order along the arrow M in FIG. 5) which the cylinders independently perform. (Fig. 5
As a result, the injection timings of the fourth cylinder and the first cylinder are performed in the exhaust stroke advantageous in terms of control response, and the injection timings of the second cylinder and the third cylinder are compressed. It is done in the process. In this way, fuel can be reliably injected into 1/2 of all cylinders in the exhaust stroke that is advantageous in terms of control response. In this way, when fuel injection of at least one-half of all cylinders is reliably executed with good control responsiveness, that is, when acceleration / deceleration operation by accelerator operation or brake operation is performed, it is appropriate to follow this operation. The fuel injection is performed with good response, and the control response of the entire internal combustion engine can be improved.

In the group ignition process in the normal operation mode, the cylinders # 1 and # 4 of the first group are in the vicinity of the exhaust top dead center or the compression top dead center with reference to the latest peculiar pulse position signal δ0. Group ignition is performed at a certain timing, and group ignition is performed at a timing when the second group of cylinders # 2 and # 3 is near the exhaust top dead center or the compression top dead center. At this time, in the first and second groups, an ignition timer (not shown) in each of the igniters 20 and 21 is set so that the ignition is alternately performed at the target ignition timing ψt while maintaining the crank angle of 180 °. .

As described above, by performing the processing in steps b6 and 7, the engine can be driven by performing the injection control in the cylinder reverse injection mode, which is the provisional mode, before operating in the independent injection mode. Moreover, at least one of all cylinders
When the fuel injection of the / 2 cylinder is executed with good control responsiveness, that is, when the acceleration / deceleration operation by the accelerator operation or the brake operation is performed, the appropriate fuel injection that follows this operation is performed with good responsiveness. Since the engine E is driven, the control response of the engine as a whole can be improved.

The identifiable flag MF in step b5 described above.
If LG is determined to be on, steps b9 and b10 are performed to perform cylinder deactivation operation processing for determining the cylinder here.
Proceed to. Here, the timer I of one of the specific cylinders (here, the first cylinder # 1) is based on the latest specific pulse position signal δ0.
The drive signal t (#n) is input only to JTIM1, and the timer IJTIM1 is set to open and close the fuel injection valve 5 of the first cylinder during the period corresponding to this signal, and the fuel injection (Fig. The code ∇ of 5) is executed. Further, the ignition process in the fuel injection cut mode is performed, that is, the ignition plugs 19 of the first and fourth cylinders # 1 and # 4, which are the first group here, are near the exhaust top dead center or the compression top dead center. Group ignition at the timing. At this time, igniter 2
The ignition timer within 0 keeps a crank angle of about 360 ° with reference to the latest peculiar pulse position signal δ0,
The target ignition timing ψt is set to ignite, the singular pulse position detection flag δFLG is cleared, and the process returns to the main routine. It should be noted that the ignition of the fourth cylinder starts from.

Further, when the above step b4 is reached again, the reference position determination described later has been completed and the reference position signal δ0.
When (b) is recognized, the cylinder determination completion flag NFLG
Is ON, and accordingly, the process proceeds to step b11. Here, the current operation range satisfies the cylinder identification condition, and the engine is operated in the independent injection mode. That is, with reference to the latest reference position signal δ0 (b), the first cylinder #
1, the third cylinder # 3, the fourth cylinder # 4, and the second cylinder # 2 in order to control the fuel injection independently of each other, the drive signal t (#n) corresponding to the fuel injection amount of each cylinder is ) Is calculated and output to the driver 11.

At this time, similarly to step b6, from the engine speed Ne, the intake air amount A, the intake air temperature Ta, the cooling water temperature T _W , the intake air amount correction coefficient according to the intake manifold pressure Pint, and the reference fuel injection amount, The current fuel injection amount is calculated. Each driver 11 opens and closes the fuel injection valve 5 during a period corresponding to the drive signal t (#n), and internal timers IJTIM1, IJTIM3, IJTIM4, IJTIM4.
Since JTIM2 is set, injection is performed at the position in the stroke phase indicated by the symbol ▼ in FIG.
At this time, since the cylinders other than the first cylinder were in a deactivated state,
Even if all-cylinder independent injection is switched here, each cylinder will not become rich during this transition, and exhaust gas will not deteriorate here. When such all-cylinder independent injection is sequentially performed for each cylinder in the same order as the order of the combustion stroke (the order along the arrow M in FIG. 5) (reference numeral ▼ in FIG. 5), the injection timing of each cylinder However, they are all located in the exhaust stroke advantageous in terms of control response, and the control response during this all-cylinder independent injection is extremely good.

In step b12 following step b11, the group ignition process in the normal operation mode similar to step b7 is performed. Here, the latest reference position signal δ0
Based on (b), the first group of cylinders # 1,
Cylinder # 4, which is the second group, is group-ignited at a timing when # 4 is near the exhaust top dead center or the compression top dead center.
Group ignition is performed at a timing when # 2 and # 3 are near the exhaust top dead center or the compression top dead center. At this time, the first and second
The groups have a crank angle of about 180 °,
An ignition timer (not shown) in each igniter 20, 21 is set so that the ignition is alternately performed at the target ignition timing ψt. Then, in step b13, the cylinder determination flag NFLG for this time is cleared, and the process returns to the main routine.

Next, in the middle of the main routine, every time the crank angle signal dθ is input, the reference position determination routine of FIG. 10 is reached. Here, it is determined in step c1 whether or not the cylinder determination flag NFLG is on. If it is on, the process returns to the main routine. If it is off, the process proceeds to step c2, where it is determined whether or not the distinguishable flag MFLG is on, and if it is off the reference position. Since the determination cannot be made, the process returns to the main routine, and when it is off, the process reaches step c3. Here, a predetermined time period Ta is waited for through step c4, and then step c5 is reached. Here, it is determined whether or not the stroke count flag SFLG is on, initially it is off and the process proceeds to step c6 to determine whether or not the specific pulse position signal δ0 is input. If No, the process returns to the main routine and Y
In es, the process proceeds to step c7, and the stroke count flag SFL
Turn on G, start the stroke counter CCUT1,
Return to the main routine.

Next, when the process reaches from step c5 to c8, the process proceeds to step c9 until the stroke counter CCUT1 is counted, and waits for a new input of the peculiar pulse position signal δ0, that is, the stroke of the first cylinder. Is 360 ° in the stroke phase (reference numeral δ0 (b) to reference numeral δ0 in FIG. 4).
It is determined that the process has proceeded, and the stroke counter C is determined in step c10.
The value of CUT1 is set as Ne1 (n-2), the stroke counter CCUT2 is started, and the process returns to the main routine.

When step c8 is reached again, the process proceeds to the No side and reaches step c11. Here, stroke counter C
Until the CUT2 is counted, the process proceeds to step c12 and waits for a new input of the unique pulse position signal δ0. If there is, that is, the stroke of the first cylinder is 360 ° in the stroke phase.
(Between reference numeral δ0 to reference numeral δ0 (b) in FIG. 4), it is determined that the value of the stroke counter CCUT2 is set to N in step c13.
e1 (n-1), and the stroke counter CCUT3
To start and return to the main routine. When step c11 is reached again, the process proceeds to the No side and reaches step c14. Here, the process proceeds to step c15 until the stroke counter CCUT3 is counted, and waits for a new input of the peculiar pulse position signal δ0. That is, if the stroke of the first cylinder is 360 ° in the stroke phase (reference numeral in FIG. 4). δ0 (b)
Up to δ0 (b)), it is determined that the process has proceeded to step c16.
Then, the value of the stroke counter CCUT3 is set as Ne1 (n), and the process proceeds to step c17. In step c17, 3
The determination as to whether the peculiar pulse position signal δ0 every 60 ° is the reference position signal δ0 (b) of 5 ° before the compression top dead center of the first cylinder or the signal of 5 ° before the exhaust top dead center of the first cylinder is shown in FIG. 6 (a). The judgment is made based on whether the mode is the positive assumption mode shown in FIG. 6 or the assumption false mode shown in FIG.

{Ne1 (n-2) + Ne1 (n)} / 2 <Ne1 (n-1) ·· (5) Here, each value fetched in steps c10, c13, and c16 is substituted into the equation (5). Then, it is determined whether or not this expression (5) is satisfied. Here, as shown in FIG.
When e1 (n-2) and Ne1 (n) are the rotational speeds of the intake stroke and the compression stroke, and Ne1 (n-1) is the rotational speeds of the combustion stroke and the exhaust stroke, the equation (5) is clearly satisfied, The assumption is positive, and conversely, as shown in FIG. 6B, Ne1 (n-
2), Ne1 (n) is the combustion and exhaust stroke rotation speed, N
When e1 (n-1) is the rotational speed of the intake stroke and the compression stroke, the equation (5) is obviously not satisfied, and the assumption is erroneous. If it is determined that the assumption is positive, the assumption correct counter GCUT is incremented by "1" in step c18, and if the assumption is incorrect, the hypothesis false counter BCUT is incremented by "1" in step c19, and the process proceeds to step c20.

At step c20, the hypothetical positive counter GCU is used.
Assuming that T is the false count counter BCUT, the process proceeds to step c21 until the added value of the counter BCUT reaches 50, and the stroke count flag SFL.
Clear G and rotate this time Ne1 (n-2), Ne
1 (n-1) and Ne1 (n) are cleared, and steps c5 to c20 are repeated again. When the determination in step c20 is Yes, step c22 is reached. 5 here
If it is determined that the value of the hypothetical correct counter GCUT or the hypothetical false counter BCUT is 40 or more during the determination of 0 times, the process proceeds to step c23, where the cylinder determined flag NFL is set.
G is turned on, the hypothetical positive counter GCUT and the hypothetical false counter BCUT are cleared, and the peculiar pulse position signal δ0 on the hypothesized side is set as the reference position signal δ0 (b) according to the present hypothetical positive or false erroneous judgment. Based on the pulse signal sequence including the reference position signal δ0 (b), the subsequent crank angle counting can be performed and the stroke phase can be recognized. At the same time, the stroke phases of the other cylinders can be recognized, and the process returns to the main routine. When the value of the hypothetical positive counter GCUT or the hypothetical false counter BCUT is less than 40, the cylinder determination completion flag NFLG, the hypothetical positive counter GCUT,
Clear the hypothetical false counter BCUT, return to the main routine side, and try again.

The hypothetical positive counter GCUT and the hypothetical false counter BCUT are not cleared before the determination is made 50 times in step c20.
Even if G is turned off, the values of both counters will be added when turned on again. Therefore, even if there is a change in the operating range, the determination of the reference position signal δ0 (b), that is, the cylinder Discrimination processing is performed. In the above-described fuel injection control device, only the crank angle sensor is used to obtain the peculiar pulse position signal δ0 by the peculiar pulse position detection process, the cylinder discrimination condition is judged in steps s7 to s10, and the discrimination possible flag MFLG is OFF. The injection control is performed in the reverse order injection mode for each cylinder in step b6. At this time, each cylinder performs the injection process in the order opposite to the order of the combustion stroke.
It is possible to perform injection in the exhaust stroke that is advantageous in terms of control response in two of the cylinders, and fuel injection that follows the acceleration / deceleration operation is performed with good response. Can be improved.

When the distinguishable flag MFLG is turned on, only the fuel injection valve 5 of the first cylinder, which is one of the specific cylinders, is injected by using the specific pulse position signal δ0 as a reference in steps b9 and b10. The rotation speed in the combustion stroke is changed as compared with the other strokes. Thus, the reference position signal δ0 (b) of the first cylinder is determined once every 720 ° from the unique pulse position signal δ0 input every 360 °, and the pulse signal sequence corresponding to this reference position signal δ0 (b) is determined. The stroke phases of the first cylinder and other cylinders are recognized based on the above, and independent injection control (sequential control) in steps b11 and b12 can be executed using the reference position signal δ0 (b) after that. Although the above-mentioned engine E is an in-line four-cylinder engine, the present invention can be similarly applied to other multi-cylinder engines and similar operational effects can be obtained. Furthermore, although the engine E of FIG. 1 adopted the group ignition system,
The present invention can be similarly applied to an independent ignition type engine.

Further, the fuel injection device of FIG. 1 uses only the crank angle sensor, and based on the peculiar pulse position signal δ0 of the sensor, performs injection control in the cylinder reverse order injection mode before cylinder discrimination, and after cylinder discrimination. Reference position signal δ0 of the sensor
Although the injection control is performed in the all-cylinder independent injection mode based on (b), in some cases, the cylinder determination process may be omitted and only the reverse-cylinder injection mode for each cylinder may be performed in the entire operation range. Also, the control response can be surely improved, and in particular, the control can be simplified and the cost of the device can be reduced.

[0044]

As described above, according to the invention described in claim 1, the specific cylinder is identified once per rotation at a specific position in its stroke phase without cylinder identification, and the sequence of combustion strokes is determined. By injecting and driving the injection valve of each cylinder in the order opposite to that described above, fuel injection in the exhaust stroke can be performed in half of all the cylinders, and the control responsiveness can be reliably improved. . That is, even if an acceleration or deceleration operation by an accelerator operation or a brake operation is performed, proper fuel injection that follows this operation is performed with good responsiveness, the control responsiveness of the internal combustion engine as a whole can be improved, and the crankshaft only the rotation angle, that is, using only the crank angle sensor, Ru results in low cost simplified and device control.

According to the invention described in claim 2, the cylinder discrimination means is provided, and before the cylinder discrimination, the control responsiveness of the internal combustion engine as a whole can be improved in the same manner as in claim 1, that is, the control can be performed. Can be simplified and the cost of the apparatus can be reduced, and after the cylinder discrimination, all cylinder independent injection with more improved control response can be performed.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a fuel injection device to which the present invention is applied.

FIG. 2 is a functional block diagram of the fuel injection device of FIG.

FIG. 3 is a basic pulse signal pattern diagram along a stroke phase of a crank angle sensor used in the fuel injection device of FIG.

FIG. 4 is a diagram showing a relative relationship in a phase stroke between a stroke pattern of each cylinder of an engine including the fuel injection device of FIG. 1 and a pulse signal used in the device.

5 is an explanatory diagram of a stroke pattern and injection timing of each cylinder of the engine of FIG.

6 is performed by the fuel injection device of FIG. 1 in reference position determination,
It is a figure which shows each mode of hypothesis positive and hypothesis as a reference signal.

FIG. 7 is a flowchart of a main routine executed by the fuel injection device in FIG.

FIG. 8 is a flowchart of a specific pulse position detection routine executed by the device of FIG.

9 is a flowchart of a fuel injection and ignition control routine executed by the device of FIG.

10 is a flowchart of a reference position determination routine performed by the fuel injection device in FIG.

FIG. 11 is an explanatory diagram of a stroke pattern and injection timing of each cylinder of an engine equipped with a conventional device, in which (a) shows simultaneous injection for all cylinders and (b) shows group injection.

[Explanation of symbols]

3 intake ports 5 Fuel injection valve 10 ECU 26 Crank angle sensor δ0 Singular pulse position signal E engine M Combustion stroke order N Combustion stroke reverse order # 1 to # 4 cylinder number dθ crank angle signal

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-6-213052 (JP, A) JP-A-58-91338 (JP, A) JP-A-59-229026 (JP, A) JP-A-5- 52172 (JP, A) JP-A-60-69247 (JP, A) JP-A-7-54691 (JP, A) JP-A-10-212990 (JP, A) Actual Kaihei 5-87245 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) F02D 41/00-45/00

Claims (2)

(57) [Claims] 1. An injection valve provided for each cylinder of an internal combustion engine having four or more cylinders, and an identification means for outputting a signal for identifying a specific cylinder based on a rotation angle of a crankshaft of the internal combustion engine. And a control means for injecting and driving the injection valve of each cylinder in the reverse order of the order of the combustion stroke performed independently by each cylinder based on the output of the above-mentioned identification means. Fuel injection device. 2. A cylinder discriminating means for discriminating a stroke phase of a cylinder in the internal combustion engine based on the output of the discriminating means, wherein the control means is provided before the cylinder phase stroke is discriminated by the cylinder discriminating means. 2. The fuel injection device according to claim 1, wherein the fuel injection control is performed in a reverse order to the order of the combustion stroke, and after the cylinder discrimination is completed, the fuel injection control is performed in the same order as the combustion stroke.