JPH05187291A - Fuel control device for internal combustion engine - Google Patents

Abstract

PURPOSE:To provide an internal combustion engine control device capable of keeping both startability and cylinder discrimination capability compatible with each other. CONSTITUTION:A signal rotor 1 rotates, interlocked with the crankshaft of an engine, and is provided with projections 2a to 2d corresponding to the number of cylinders at equal intervals for detecting an crank angle. In addition, a cylinder discrimination projection 3 is so formed on the rotor 1 as to divide an interval following the projection 2a into unequal intervals. The passage signals of the projections 2a to 2d and 3 are inputted from an electromagnetic pickup 4 to a microcomputer 6, and the passage of the projection 3 is detected on the basis of the time interval of the inputted signals. Also, the microcomputer 6 starts outputting an instruction signal for fuel injection to all the cylinders of the engine concurrently with the inputted passage signals, when only two signals are inputted after inputting the passage signals following the actuation of a starter.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for an internal combustion engine, and more particularly to a control device for an internal combustion engine which outputs a fuel injection command signal, an ignition command signal and the like by detecting a crank angle.

[0002]

2. Description of the Related Art Conventionally, a control device for an internal combustion engine is disclosed in Japanese Patent Publication No.
-49044. This device is
In the signal rotor that rotates in synchronization with the crankshaft of the engine
Install the number of detected objects for crank angle detection at equal intervals for the number of cylinders.
And a predetermined one crank angle detection object
To divide one of the following intervals into unequal intervals
An object to be detected for reference position detection is provided, and as shown in FIG.
Three time intervals of the passing signal (N signal) of the detected object
(T_i-2, T_i-1, T_i) By T_i-2・ T_i/ T _i-1
²> Cylinder discrimination is performed when the constant k is satisfied, and fuel injection control and point
It controls the fire timing. In this way, using 3 information
By doing so, it is possible to accurately determine the cylinder. When
Roller starts injection and ignition after cylinder discrimination in this way
In this case, before determining the cylinder when starting the engine
Is unable to inject fuel and ignite
It becomes a problem. Therefore, as shown in FIG.
For cranking, 2 information (2 time intervals)
T_i-1, T_i), T_i-1/ T_i<To establish the constant k
Cylinder discrimination is performed by using the crank, as shown in FIG.
With the input of the passage signal of the detected object for angle detection,
Crank angle detection object to output injection command signal
Time interval T of passing signals_i1/4 of the mask area
Even if a signal comes in this section, it is invalidated and the reference position
Erroneous ejection due to the passing signal (additional pulse) of the detected object for position detection
It is designed to prevent fire and misfiring.

[0003]

However, before the cylinder discrimination based on the three pieces of information (before capturing the entire rotation fluctuation pattern).
If the rotation fluctuation is extremely large, such as from explosion to misfire, a method such as cylinder identification using two pieces of information or masking an additional pulse will cause a malfunction. That is, as shown in FIG. 14, when explosion → misfire, the rotation slows down at the time of misfire, so the pulse interval T _i0 becomes longer and, as a result, the mask interval (T
_i0 / 4) also becomes longer, the crank angle detection pulse is masked, and the fuel injection command signal is not output and fuel injection is not performed.

Therefore, an object of the present invention is to provide a control device for an internal combustion engine, which can achieve both startability and cylinder discrimination.

[0005]

SUMMARY OF THE INVENTION According to the present invention, a crank angle detecting object provided with a number of cylinders at equal intervals to a signal rotor rotating in synchronization with a crankshaft of an internal combustion engine, and a predetermined one crank. Reference position detecting detection object provided in the signal rotor so as to divide one of the intervals subsequent to the angle detecting detection object into unequal intervals, and passage detecting means for detecting passage of the detection object In the control device for an internal combustion engine, which is configured to input a detection object passage signal by the passage detection means and detect passage of the reference position detection detection object by a time interval between the signals, an engine start is started. The fuel injection command signal to all the cylinders of the internal combustion engine is output in response to the input of the detected object passage signal from the time when a predetermined number of the detected object passage signals are input by the passage detection means later. The internal combustion engine control apparatus adapted to the gist thereof.

Further, it is preferable to output the ignition command signal from a time point when a predetermined number of passing signals of the crank angle detecting object are input after the output of the fuel injection command signal.

[0007]

In a state where passage of the reference position detecting object cannot be detected due to the time interval between the object passing signals after the start of the engine, a predetermined number of the signals are input after the passage detecting means inputs the object passing signal. The fuel injection command signal to all the cylinders of the internal combustion engine is output in response to the input of the detection object passage signal from the time when only the input is made. That is, erroneous injection is prevented by not performing fuel injection until the time when there is no effect of explosion → misfire as shown in FIG.

Further, at the time when a predetermined number of passing signals of the detected object for crank angle detection are input after the output of the fuel injection command signal, that is, after two strokes in a four-cycle engine, for example,
An ignition command signal is output. As a result, it is possible to avoid the adverse effect of the air-fuel mixture in the cylinder before fuel injection.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows the overall configuration of an internal combustion engine control device according to this embodiment, in which a four-cylinder, four-cycle gasoline engine is installed in an automobile.

A signal rotor 1 that rotates in synchronization with the cam shaft is fixed to the cam shaft of the engine. In this embodiment, one rotation of the signal rotor 1 corresponds to two rotations of the crankshaft.

On the outer peripheral surface of the signal rotor 1, four crank angle detecting protrusions (crank angle detecting objects) 2a,
2b, 2c, and 2d are provided at equal intervals every 90 °. The crank angle detecting protrusions 2a, 2b, 2c, 2d
Is provided at a crank angle (for example, 10 ° CA before the top dead center of each cylinder) set while the crankshaft of the engine shifts from the bottom dead center to the top dead center of each cylinder. Further, a cylinder discriminating projection (reference position detecting object) 3 is provided on the outer peripheral surface of the signal rotor 1, and the cylinder discriminating projection 3 does not follow the predetermined one crank angle detecting projection 2a. They are arranged at equal intervals of 15 °. The protrusion 3 for cylinder discrimination is
It is provided at a predetermined crank angle (for example, 20 ° CA after top dead center) during the transition from top dead center to bottom dead center of one cylinder.

The crank angle detecting protrusions 2a, 2b, 2
The c and 2d and the cylinder discrimination projection 3 are made of magnetic material. Furthermore, each protrusion 2a, 2b, 2c, 2d,
An electromagnetic pickup 4 as a passage detecting means is arranged in the vicinity of the passage position of 3, and as shown in FIG.
The passage of b, 2c, 2d and 3 is detected. The electromagnetic pickup 4 is constructed by winding a coil (not shown) around a magnetic core (not shown). Then, the crank angle detecting protrusions 2a, 2b, and
The passage interval of 2c and 2d corresponds to 180 ° CA, and the cylinder discrimination protrusion 3 corresponds to the position of 30 ° CA after passage of the crank angle detection protrusion 2a.

The electronic control unit (hereinafter referred to as ECU) 5 in FIG. 1 comprises a microcomputer 6, a waveform shaping circuit 7 and an A / D conversion circuit 8. The waveform shaping circuit 7 inputs the output signal (pickup signal) of the electromagnetic pickup 4 and shapes the waveform of the signal. That is, as shown in FIG.
The pickup signal output from the electromagnetic pickup 4 is binarized into a pulse signal by the threshold value Vref.

The A / D conversion circuit 8 includes an intake pipe pressure sensor 9
Is connected to the water temperature sensor 10, and the A / D conversion circuit 8 converts the intake air pressure detection signal (analog signal) from the intake pipe pressure sensor 9 and the engine cooling water temperature detection signal (analog signal) from the water temperature sensor 10 into digital signals. Convert. The microcomputer 6 inputs the output signal of the electromagnetic pickup 4 via the waveform shaping circuit 7 and the intake air pressure detection signal and the water temperature detection signal via the A / D conversion circuit 8. Further, the microcomputer 6 inputs the starter on signal from the starter motor 11.

The microcomputer 6 includes an injector 1 for each cylinder.
2a, 12b, 12c, 12d are connected, and each injector 12a, 12b, 12c, 12d performs a fuel injection operation according to a fuel injection command from the microcomputer 6. Further, an igniter 13 is connected to the microcomputer 6, and an ignition command from the microcomputer 6 causes the ignition plugs 16a, 16b, 16c, 16d for each cylinder to ignite through the igniter 13, the ignition coil 14, and the distributor 15.

A battery 18 is connected to the ECU 5 via a key switch 17, and electric power from the battery 18 is supplied to each device in the ECU 5 by turning on the key switch.

Further, the microcomputer 6 receives from the waveform shaping circuit 7 the crank angle detecting projections 2a, 2 by the electromagnetic pickup 4.
b, 2c, 2d and the passage signal (pulse signal) of the cylinder discrimination projection 3 are input to calculate the time intervals Ti, Ti-1, ... Between the pulse signals as shown in FIG. ,
In order to prevent erroneous discrimination, the cylinder discrimination is performed by detecting the passage of the cylinder discrimination projection 3 at the time interval between the three pulse signals. That is, as shown in FIG. 4, the current sampling value T
_{Based on i} , the previous sampling value T _i-1 and the _{two -} preceding sampling value T _{i- 2} , it is determined whether or not T _i-2 · T _i / T _i-1 ² > k1. However, k1 is a discriminant constant (for example, "5").

However, since the cylinder discrimination based on these three pieces of information has a problem in startability, at the time of start-up (starter-on and before cylinder discrimination), the cylinder discrimination projection 3 is caused by the time interval between two pulse signals. Cylinder discrimination is performed by detecting passage. That is, as shown in FIG. 3, it is determined from the current sampling value T _i and the previous sampling value T _i-1 whether T _i-1 / T _i <k2. However, k2 is a discriminant constant (for example,
"0.6"). Further, at the time of starting, as shown in FIG. 2, in order to mask the pulse signal accompanying the passage of the cylinder discrimination projection 3, 1/4 of 180 ° CA time (= T _i /
4) is a mask section, and when the pulse signal is input within this section, only the cylinder discrimination calculation is performed and the pulse signal is invalidated (shown at the timing of t1 in FIG. 2).

Further, FIGS. 3, 4, 5, 6 and 7 show a pulse signal input state at the start of engine start (when the starter is on). 3 shows the case where a pulse signal immediately before the pulse signal accompanying the passage of the cylinder discrimination projection 3 is input first, and FIG. 4 shows the case where the pulse signal accompanying the passage of the cylinder discrimination projection 3 is input first. First, FIG. 5 shows the projection 3 for cylinder discrimination.
7 shows a case in which a pulse signal before the pulse signal associated with the passage of 4 is input, and FIG. 6 illustrates a case in which the pulse signal 3 before the pulse signal associated with the passage of the cylinder identification projection 3 is input. Shows the case where the pulse signal two before the pulse signal accompanying the passage of the cylinder discrimination projection 3 is input first. Then, in FIG. 3, t3 to t8 after the starter is turned on.
The cylinder discrimination based on the 2 information is established at the timing of, and the cylinder discrimination based on the 3 information is established after the timing of t8. In FIG. 4, the cylinder discrimination based on the three pieces of information is established after the timing t7 after the starter is turned on. In FIG. 5, the cylinder discrimination based on the three pieces of information is established after the timing t6 after the starter is turned on. In FIG. 6, the cylinder discrimination based on the three pieces of information is established after the timing t5 after the starter is turned on. In FIG. 7, the cylinder determination based on the three pieces of information is established after the timing t4 after the starter is turned on.

Next, the operation of the control device for an internal combustion engine configured as above will be described. The microcomputer 6 is shown in FIGS.
7 shows a process (flowchart) executed by. This process is mainly performed before the cylinder discrimination after the starter is turned on, that is, before t3 in FIG. 3, before t7 in FIG. 4, and t in FIG.
6 shows the output timings of the fuel injection command and the ignition command before 6 and before t5 in FIG. 6 and before t4 in FIG. FIG. 8 shows a signal input from the electromagnetic pickup 4 when the engine is started (falling edge of pulse signal).
It is a routine that is executed for each time.

First, the microcomputer 6 executes step 100 in FIG.
Cylinder discrimination processing is performed. The details of this processing are shown in FIG.
In step 110, the microcomputer 6 performs a cylinder discrimination process (T _i-2 · T _i / T _i-1 ² > k1) based on three pieces of information.

Then, the microcomputer 6 determines in step 120 whether or not the starter motor 11 is on and the cylinder discrimination condition based on the 3 information or 2 information is satisfied. Here, the starter-on determination is for confirming that the starter motor 11 is not in a so-called pushing mode in which the vehicle is cranked without pushing the starter motor 11. If the condition of step 120 is satisfied, the microcomputer 6 increments the actual pulse counter CNIN by "1" at step 130. Further, in step 140, the microcomputer 6 executes the cylinder discrimination processing (T _i-1 / T _i) based on the two information.
<K2).

Then, the microcomputer 6 carries out mask processing of the additional pulse in step 150. The details of this mask processing are shown in FIG. First, in step 151, the microcomputer 6
The 1/4 hour of the 180 ° CA time T _i is compared with the time until the next rise of the pulse signal, and it is determined whether or not the pulse signal is the pulse signal (additional pulse) accompanying the passage of the cylinder discrimination projection 3. When the condition of step 151 is satisfied by the microcomputer 6,
Flag FMS in step 152 as not additional pulse
Set K to "1". Then, the microcomputer 6 proceeds to step 15
At 3, the cylinder counter CNMSK is incremented by "1" and the process returns. On the other hand, the microcomputer 6 executes step 151
If the conditions are not satisfied at (t6 in FIG. 4 and t in FIG. 5)
5, each timing of t4 in FIG. 6 and t3 in FIG. 7), the flag FMSK is set to “0” in step 154 as an additional pulse, and the process returns.

The initial values are counters CNIN and CNM.
Both SK are "0" and the flag FMSK is "1". This is set when the key switch 17 is reset and the engine stall is determined (when the time intervals Ti, Ti-1, ... Between the pulses are equal to or greater than the determination value (for example, 200 ms)).

The microcomputer 6 determines in step 200 in FIG. 8 that the actual pulse counter CNIN has an even value of 2 or more (that is, two or more pulse signals have been input), and the flag FM.
SK determines "1" (that is, whether it is an additional pulse). That is, in FIG. 3 to FIG. 7, 2 after the starter is turned on.
It is determined whether or not it is an even-numbered pulse falling edge (timing of t1) after the th.

Then, the microcomputer 6 satisfies the condition of step 200 (t2 in FIG. 3, t2 in FIG. 4).
t4, t2, t4 in FIG. 5, t2 in FIG. 6, t in FIG.
2) In step 300, simultaneous injection processing for all cylinders is performed.
This is to calculate the fuel injection time (injection amount) using a table based on the water temperature, correction based on the engine speed NE, and the like, and to output a signal according to the calculated fuel injection time. After the injection is started, the microcomputer 6 starts the cylinder counter CNMSK in step 400.
Is 3 or more and the flag FMSK is not "1" (that is, whether it is an additional pulse), and if the conditions are satisfied (t3, t4, t5 in FIG. 4, and in FIG. 5). t
3, t4, and t3 in FIG. 6), ignition processing is performed in step 500. This permits the output of the ignition signal having the same shape as the pulse input in synchronization with the next pulse input (t4 ′, t5 ′, t7 ′ in FIG. 4, t4 ′,
t6 ′, t5 ′ in FIG. 6).

On the other hand, the microcomputer 6 executes steps 200, 4
If the condition is not satisfied at 00, steps 300, 4
The processing of 00,500 is not performed. That is, in FIGS. 3 to 7, the fuel injection command is not issued at the first pulse falling edge (timing of t1 in each figure) after the starter is turned on, and up to the third pulse after the starter is turned on. If the pulse is on the trailing edge (timing t1, t2, t3 in each figure), the ignition command is not issued.

After that, the microcomputer 6 returns to 2 or 3
When the cylinder discrimination condition is satisfied by the information, the injection command signal and the ignition command signal for each cylinder are output. At this time, the fuel injection time (injection amount) is obtained using a map of the engine speed NE and the intake pressure Pm, and is corrected and determined by the engine cooling water temperature by the water temperature sensor 10.

As described above, the cylinder discrimination and the mask processing based on the two pieces of information at the time of starting must be limited to the time when the rotation in cranking without explosion is stable, so that the first time after the starter is turned on. When injection / ignition is started from the pulse signal of, as described in FIG.
In the operation mode such as explosion → misfire before cylinder discrimination, it malfunctions. Therefore, by delaying the start of injection and ignition until there is no effect of explosion → misfire, both reliability and startability are achieved. In other words, after two strokes (360 ° CA) from intake to compression after the start of injection, an explosion occurs, the rotation speed rises, then misfires, and the rotation speed sharply decreases. Before starting to make a mistake, the injection start is delayed until the point where the 3 information can be accurately determined (the second pulse signal). Also, by starting the ignition at the second (two strokes) of the pulse signals of the crank angle detecting protrusions 2a, 2b, 2c, 2d after the start of injection, mixing in the pre-injection cylinder at the time of restarting the engine stall, etc. Explosion when there is energy → It can prevent a case of falling into a misfire.

As described above, in this embodiment, when only two signals are inputted after the passage signal of the cylinder discriminating projection 3 (object to be detected) is input by the electromagnetic pickup 4 (passage detecting means) after starting the engine. Therefore, the fuel injection command signal to all the cylinders of the engine is output in response to the input of the passage signal, and the ignition command signal is output after being delayed by two strokes after the signal output. Therefore, by delaying the injection start until the second pulse input before the position (three-information cylinder discrimination position) where the entire rotation fluctuation pattern can be detected, there is no effect of explosion → misfire, and By delaying the ignition start by two strokes from the start, there is no influence of explosion → misfire due to the air-fuel mixture remaining in the cylinder before injection. As a result, the same sensor can be used for the reference position and the rotation angle to reduce costs, improve reliability, and improve startability.

The present invention is not limited to the above embodiment. For example, in the above embodiment, in the case of a 4-cylinder 4-cycle gasoline engine, fuel injection is started from the time when two pulse signals are input after the starter is turned on. Although the command signal is output, the start timing (pulse number) for outputting the fuel injection command signal may be appropriately changed and set depending on the number of cylinders and the number of cycles.

[0032]

As described in detail above, according to the present invention,
It has an excellent effect of achieving both startability and cylinder discrimination.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a control device for an internal combustion engine of an embodiment.

FIG. 2 is a diagram for explaining signal processing.

FIG. 3 is a diagram for explaining signal processing.

FIG. 4 is a diagram for explaining signal processing.

FIG. 5 is a diagram for explaining signal processing.

FIG. 6 is a diagram for explaining signal processing.

FIG. 7 is a diagram for explaining signal processing.

FIG. 8 is a flowchart for explaining the operation.

FIG. 9 is a flowchart for explaining the operation.

FIG. 10 is a flowchart for explaining the operation.

FIG. 11 is a time chart for explaining a conventional technique.

FIG. 12 is a time chart for explaining a conventional technique.

FIG. 13 is a time chart for explaining a conventional technique.

FIG. 14 is a time chart for explaining a conventional technique.

[Explanation of symbols]

1 Signal Rotors 2a, 2b, 2c, 2d Crank Angle Detection Protrusions as Crank Angle Detection Detected Objects 3 Cylinder Discrimination Protrusions as Reference Position Detection Detected Objects 4 Electromagnetic Pickup 6 as Pass Detection Means 6 Microcomputer

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location // F02N 17/00 Z 9149-3G

Claims (2)

[Claims] 1. A crank angle detecting object provided at the same number of cylinders as a signal rotor rotating in synchronization with a crankshaft of an internal combustion engine, and a predetermined one crank angle detecting object subsequent to the crank angle detecting object. A reference position detection target object provided in the signal rotor so as to divide the one interval into unequal intervals, and a passage detection unit that detects passage of the detection target,
In the internal combustion engine control device, wherein the passage signal of the object to be detected by the passage detecting means is input and the passage of the object to be detected for reference position detection is detected by the time interval between the signals, the passage after the engine start is started. From the time when a predetermined number of signals are input after the detection target passage signal is input by the detection means, the fuel injection command signal to all the cylinders of the internal combustion engine accompanying the input of the detection target passage signal is output. A characteristic control device for an internal combustion engine. 2. The internal combustion engine control device according to claim 1, wherein the ignition command signal is output from a time point when a predetermined number of passing signals of the crank angle detecting object are input after the output of the fuel injection command signal. .