JP2834370B2 - Internal combustion engine control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an internal combustion engine control apparatus for controlling fuel injection and ignition timing for each cylinder based on a reference position of a crank angle, and more particularly to a backup function for failure of a cylinder identification signal generating means. The present invention relates to an internal combustion engine control device provided with:

[0002]

2. Description of the Related Art Generally, in an internal combustion engine such as an automobile engine, it is necessary to optimally control fuel injection and ignition timing according to operating conditions. For this reason, a microcomputer for recognizing a crank angle reference position for each cylinder, calculating ignition timing and the like, and performing timer control is used.

FIG. 7 is a block diagram showing a conventional internal combustion engine control apparatus, for example, showing a case where group ignition control is performed on each of two cylinders out of four cylinders. In the drawing, reference numeral 1 denotes a reference position signal generating means for generating a reference position signal T corresponding to a crank angle reference position for each cylinder in synchronization with the engine rotation, and 2 denotes a cylinder identification signal for identifying a specific cylinder in synchronization with the engine rotation. C is a cylinder identification signal generating means for generating C. The reference position signal generating means 1 and the cylinder identification signal generating means 2
As will be described later, it is composed of a rotating slit provided on a crankshaft or a camshaft, and a photocoupler facing the rotating slit.

Reference numeral 3 denotes control means comprising a microcomputer, which recognizes a reference position of each cylinder based on a reference position signal T and a cylinder identification signal C, calculates an ignition timing or the like in accordance with an operation condition, and calculates an ignition timing. A corresponding control signal (ignition coil energization cutoff signal) is output. Reference numeral 41 denotes an ignition coil for the cylinders # 1 and # 4, and reference numeral 42 denotes an ignition coil for the cylinders # 3 and # 2, which are driven by a control signal from the control means 3.

[0005] The control means 3 performs an input interface 31 for processing the reference position signal T and the cylinder identification signal C by waveform processing.
And 32, a timing control unit 33 that calculates the ignition timing of each cylinder based on the signals T and C and the operating conditions, an output interface 34 that outputs each control signal corresponding to the ignition timing to the ignition coils 41 and 42, and 35 and.

FIG. 8 is a perspective view showing a specific structure of the reference position signal generating means 1 and the cylinder identification signal generating means 2.
Is a cam shaft that rotates in synchronization with the engine rotation, and 11 is a signal plate that is fixed to the cam shaft 10 and rotates in synchronization with the engine. 12,
13 and 14 are a plurality of slits formed concentrically along the rotation direction of the signal plate 11, the outer slit 12 corresponds to the reference position signal T of each cylinder, and the inner slits 13 and 14 are specific cylinders. Corresponding to the cylinder identification signal C.

Reference numerals 15 and 17 denote light emitting elements, 16 and 18 denote light receiving elements, and the light emitting element 15 and the light receiving element 16 constitute a photocoupler arranged opposite to the slit 12 for a reference position signal.
The light emitting element 17 and the light receiving element 18 constitute a photocoupler arranged to face the slits 13 and 14 for the cylinder identification signal.

FIG. 9 shows a reference position signal T and a cylinder identification signal C.
FIG. 11 is a timing chart showing that I1 is the ignition coil 41;
And I2 are waveforms of the coil current of the ignition coil 42. The reference position signal T is B65 ° (TDC) of each cylinder.
The pulse waveform rises at a crank angle of 65 ° before this, and falls at a crank angle of B5 °. B65 ° is a reference reference position, and B5 ° is an initial reference position.

When converted into crank angles, the total cycle of the reference position signal T for the four cylinders is 720 °, the pulse cycle of each cylinder is 180 °, and the reference reference position B is 65 °.
From the initial reference position B5 ° to 60 °,
The pulse width from the initial reference position B5 ° of one cylinder to the reference reference position B65 ° of the next cylinder is 120 °.

On the other hand, the cylinder identification signal C has a pulse waveform different in phase from the reference position signal T so that the signal level for each of the reference positions B5 ° and B65 ° is different for the specific cylinder. For example, the specific cylinder is identified by the signal level at the reference position B65 ° being “1” and the signal level at the reference position B5 ° being “1”.

Next, referring to FIGS. 8 and 9, FIG.
The operation of the conventional internal combustion engine control device shown in FIG. When the engine rotates, the reference position signal generation means 1 and the cylinder identification signal generation means 2 output the reference position signal T as shown in FIG.
And a cylinder identification signal C, which is input to the timing control unit 33 in the control means 3 via the input interfaces 31 and 32.

The control means 33 recognizes the reference position of each cylinder and each cylinder to be controlled based on the reference position signal T and the cylinder identification signal C, and calculates a control timing such as an ignition timing according to an operation state. For example, a control signal corresponding to the ignition timing is output via the output interfaces 34 and 35. At this time, when the ignition timing is advanced, timer control based on the reference reference position B65 ° is performed, and when the ignition timing is retarded, timer control based on the initial reference position B5 ° is performed. .

However, if one of the reference position signal T or the cylinder identification signal C cannot be obtained due to the failure of the photocouplers 15 to 18 or the failure of the slits 12 to 14, it becomes difficult to recognize the cylinder or the reference position. The timing control unit 33 does not function at all. In particular, if such a failure occurs during driving on a highway or the like, it can easily lead to a very dangerous accident and significantly impairs the safety of the driver.

[0014]

As described above, the conventional internal-combustion-engine control apparatus has a reference position signal T and a cylinder identification signal C.
, The control signal is generated based on the control signal, the control becomes impossible if one of the reference position signal T or the cylinder identification signal C goes down.

The present invention has been made to solve the above problems, and has as its object to provide an internal combustion engine control device capable of performing backup control even if one of the signal systems fails.

[0016]

SUMMARY OF THE INVENTION An internal combustion engine control apparatus according to the present invention includes a plurality of cylinder identification signal generating means for generating mutually different cylinder identification signals in synchronization with rotation of an engine, and based on each cylinder identification signal. Control means for controlling the engine, wherein each cylinder identification signal comprises a plurality of pulses corresponding to each cylinder, and wherein the plurality of pulses have a first pulse width having a first pulse width corresponding to a reference position for each cylinder. If, and the first pulse having a first pulse width is smaller than the second pulse width
And a second pulse generated during a generation interval, the control means, the internal reference position signal generating means for generating a reference position signal corresponding to the reference position based on the logical sum of the cylinder identification signal, the reference position Determining means for determining that each cylinder identification signal is normal based on the signal;
When it is determined that
Controls engine based on the position signal, when one of the cylinder identification signal is determined not to be normal are those comprising a backup means for controlling the engine based on only the other cylinder identification signal.

[0017]

According to the present invention, a reference position signal is generated based on the logical sum of each cylinder identification signal composed of a plurality of pulses corresponding to each cylinder, and the engine is controlled based on each cylinder identification signal and the reference position signal. When one of the cylinder identification signals goes down, the engine is controlled based only on the other cylinder identification signal.

[0018]

【Example】

Embodiment 1 FIG. Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a first embodiment of the present invention. Reference numerals 34, 35, 41 and 42 are the same as those described above. or,
3A and 31A to 33A are control means 3, input interface 3
1, 32 and the timing control unit 33 respectively.

Reference numerals 21 and 22 denote a plurality of cylinder identification signal generating means, which are different from each other in synchronization with the rotation of the engine.
Generate C1 and C2. The cylinder identification signals C1 and C2 are input to the control unit 3A via the input interfaces 31A and 32A. Each of the cylinder identification signals C1 and C2 is composed of a plurality of (four) pulses corresponding to each cylinder, as will be described later, and these pulses have a first pulse width corresponding to a reference position for each cylinder. a first pulse, a first path to not participate in and the reference position having a first pulse width is smaller than the second pulse width
A second pulse generated during the interval between the occurrences of the lus .

Reference numeral 36 denotes an OR gate inserted between the input interfaces 31A and 32A and the timing control unit 33A and serving as internal reference position signal generating means. The OR gate 36 is set at a reference position based on the logical sum of the cylinder identification signals C1 and C2. A corresponding reference position signal T 'is generated.

In this case, the timing control unit 33A performs cylinder identification and reference position recognition based on the cylinder identification signals C1 and C2 and the reference position signal T ', and calculates the ignition timing for each cylinder. Further, the timing control section 33A outputs each cylinder identification signal.
The signal levels of C1 and C2 are constantly monitored and each cylinder identification signal C1
Determination means for determining that C2 and C2 are normal, and backup means for controlling the engine based on only the other cylinder identification signal when one of the cylinder identification signals C1 or C2 is determined to be incorrect. I have.

FIG. 2 is a perspective view showing a specific structure of the cylinder identification signal generating means 21 and 22.
1, corresponding to slits 12 and 13, and 10 and 15 to 18 are the same as described above. In this case, the outer slit 12
A corresponds to one cylinder identification signal C1, and the inner slit 13
A corresponds to the other cylinder identification signal C2.

FIG. 3 is a timing chart showing pulse waveforms of the cylinder identification signals C1 and C2, where T1 is a first pulse width corresponding to the reference positions B65 ° and B5 ° for each cylinder, and P1 is a first pulse width. A first pulse having T1, T2 being a second pulse width smaller than the first pulse width T1, P2 being a second pulse width
With T2 and without affecting the reference positions B75 ° and B5 °
A second pulse that occurs during the interval between the occurrences of one pulse P1 ,
T 'is a reference position signal generated by the logical sum of the cylinder identification signals C1 and C2.

In this case, the cylinder identification signals C1 and C2 are composed of a combination of the first and second pulses P1 and P2, respectively. Further, the first pulse width T1 is equal to the second pulse width T2.
Is set to include such a relationship. FIG. 4 shows the control unit 33A.
FIG. 5 is a flowchart showing an abnormal-time control routine in FIG. 4, and FIG. 6 is an explanatory diagram showing an ignition timing setting operation in abnormal-time control together with the cylinder identification signal C1 or C2 and the coil current I. .

In FIG. 6, T (n) is the current pulse cycle of the cylinder identification signal C1 or C2 obtained properly, T (n-1) is the previous pulse cycle, and T (n + 1) is the next pulse cycle. , T1
(n) is the current first pulse width, and T2 (n + 1) is the next second pulse width.
Is the crank angle cycle with respect to the reference position B65 °, and θα is the crank angle corresponding to the offset of the second pulse P2.

Further, θ _ON is a crank angle at which power is supplied to the ignition coil of the cylinder to be controlled, θ _OFF is a crank angle at which power is cut _off, that is, ignition timing, T _ON is a timer control time for starting power supply, and T _OFF is a timer control time for power off. It is. Here, the reference reference position B65 ° is used as a reference for the timer control time.

Next, the operation of the first embodiment of the present invention shown in FIG. 1 will be described with reference to FIGS. When the engine rotates, the cylinder identification signal generating means 21 and 22 generate the cylinder identification signals C1 and C2 as shown in FIG. 3, and input them to the control means 3A via the input interfaces 31A and 32A. Each of the cylinder identification signals C1 and C2 includes a first pulse P1 having a long pulse width T1 corresponding to the reference position of each cylinder and a second pulse P2 having a short pulse width T2 corresponding to each cylinder. .

These OR signals C1 and C2 are ORed by the OR gate 36, and a reference position B65 for each cylinder is provided.
And the reference position signal T ′ corresponding to B5 °. The reference position signal T 'is generated in association with only the first pulse P1, rises and falls in synchronization with the rise and fall timings of the first pulse P1, and is controlled together with the cylinder identification signals C1 and C2. Input to the unit 33A.

The timing control unit 33A interrupts the processing of FIG. 4 at every rising timing of the reference position signal T ', for example. That is, the level of each cylinder identification signal C1 and C2 is read, and the signal level sequence is stored as storage information.
(Step S1), it is determined whether each of the cylinder identification signals C1 and C2 is normal (Step S2). If the cylinder identification signals C1 and C2 are normal, normal control is executed (step S3), and if one of the cylinder identification signals C1 and C2 is not normal, abnormal control is executed (step S4).

In the case of the normal time control step S3, the timing control section 33A outputs the reference position signal T 'and the cylinder identification signal C1.
And the reference position of each cylinder and each cylinder to be controlled based on C2 and C2, and calculates control timing such as ignition timing according to the operating state, and outputs a control signal corresponding to the calculation result.

In the case of the abnormal time control step S4, the backup means in the timing control section 33A outputs a control signal based on only the normal one of the cylinder identification signals C1 and C2 by the processing of FIG. . First, the duty ratio D of the pulses P1 and P2 is determined for each pulse cycle, and the duty ratio D
Is greater than or equal to a predetermined value β (step S41). Here, the predetermined value β is the first or second pulse width T1 or T2.
Is set to a value that can be determined.

If the pulse in the operation cycle is the first pulse
If P1 (n), D ≧ β is determined in step S41, and control times T _ON and T _OFF for the second pulse P2 (n + 1) in the next cycle are calculated (step S42). At this time, the control time T _ON for energization start and the control time T _OFF for energization cutoff are:

T _ON = {(θ _ON -θα) / θ 1} · {T 1 · θ 1 / (θ 1 + θα)} T _OFF = {(θ _OFF -θα) / θ 1} · {T 1 · θ 1 / (θ 1 + θα)}

Is given by That is, the second pulse P2
Is used as a reference, so that the control time is corrected to be short.

On the other hand, the pulse in the operation cycle is the second pulse
If P2, D <β is determined in step S41,
Control time T _ON for the first pulse P1 in the next cycle
And T _OFF are calculated (step S43). At this time, the control time T _ON for starting the current supply and the control time T _OFF for cutting off the current supply.
Is

T _ON = {θ _ON / θ 1} · {T 1 · θ 1 / (θ 1 −θα)} T _OFF = {θ _OFF / θ 1} · {T 1 · θ 1 / (θ 1 −θα)}

Is given by That is, the first pulse P1
Is used as a reference, so that the control time is corrected to be longer.

In this manner, an appropriate control signal for each of the cylinders # 1 to # 4 can be generated based on only one of the cylinder identification signals C1 and C2. Therefore, the cylinder identification signal generating means
Even if 21 or 22 breaks down, highly reliable operation control becomes possible, and driver safety can be ensured. If both of the cylinder identification signals C1 and C2 fail, backup becomes impossible, but the possibility of simultaneous failure of the two signal systems is extremely small, so there is almost no problem.

Embodiment 2 FIG. In the first embodiment, the cylinder identification signals C1 and C2 alternately generate the first and second pulses P1 and P2, taking the case of the group ignition control as an example. If the generation order of the pulses P1 and P2 is set to various combinations, it goes without saying that the present invention can be applied to the case of individual ignition control for each cylinder.

Embodiment 3 FIG. Further, in the first embodiment, the case of four cylinders has been described, but an internal combustion engine of another number of cylinders may be controlled.

[0041]

As described above, according to the present invention, a plurality of cylinder identification signal generating means for generating mutually different cylinder identification signals in synchronization with the rotation of the engine, and controlling the engine based on each cylinder identification signal. Control means, wherein each cylinder identification signal comprises a plurality of pulses corresponding to each cylinder, wherein the plurality of pulses include a first pulse having a first pulse width corresponding to a reference position for each cylinder; It is of and has a pulse width smaller than the second pulse width occurs between the first pulse generation interval
And a second pulse that the control means, the internal reference position signal generating means for generating a reference position signal corresponding to the reference position based on the logical sum of the cylinder identification signals, the reference position signal
Determination means for determining that the cylinder identification signal is normal based, with each cylinder identification signal is determined to be legitimate
Function based on each cylinder identification signal and reference position signal.
And a backup means for controlling the engine based only on the other cylinder identification signal when it is determined that one of the cylinder identification signals is not normal. And the engine is controlled based on only the other cylinder identification signal when one of the cylinder identification signals goes down, so that an internal combustion engine control device capable of backing up the cylinder identification is obtained. There is.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a first embodiment of the present invention.

FIG. 2 is a perspective view showing a specific structure of a cylinder identification signal generating means in FIG.

FIG. 3 is a waveform diagram showing a cylinder identification signal and a reference position signal generated in the first embodiment of the present invention.

FIG. 4 is a flowchart showing an operation of the first embodiment of the present invention.

FIG. 5 is a flowchart showing an abnormal-time control routine in FIG. 4;

FIG. 6 is an explanatory diagram illustrating an abnormal-time control operation according to the first embodiment of the present invention.

FIG. 7 is a block diagram showing a conventional internal combustion engine control device.

FIG. 8 is a perspective view showing a specific structure of a reference position signal generating means and a cylinder identification signal generating means in FIG.

FIG. 9 is a waveform diagram showing a reference position signal and a cylinder identification signal generated by a conventional internal combustion engine control device together with a coil current.

[Explanation of symbols]

 21, 22 Cylinder identification signal generating means 3A Control means 33A Timing control section 36 OR gate (internal reference position signal generating means) T 'Reference position signal B5 °, B65 ° Reference position C1, C2 Cylinder identification signal P1, P2 Pulse T1, T2 pulse width

Claims (1)

(57) [Claims] A plurality of cylinder identification signal generating means for generating mutually different cylinder identification signals in synchronization with rotation of the engine; and a control means for controlling the engine based on each of the cylinder identification signals. Each cylinder identification signal includes a plurality of pulses corresponding to each cylinder, wherein the plurality of pulses are: a first pulse having a first pulse width corresponding to a reference position for each cylinder; and the first pulse. A second pulse having a second pulse width smaller than the width and being generated during the generation interval of the first pulse , wherein the control means is configured to perform a logic operation based on a logical sum of the cylinder identification signals. Internal reference position signal generating means for generating a reference position signal corresponding to the reference position, determining means for determining that each of the cylinder identification signals is normal based on the reference position signal, and wherein each of the cylinder identification signals is Regular When it is determined that
Is based on each of the cylinder identification signals and the reference position signal.
Controlling the engine Te, one of the cylinder identification signal is characterized in that it comprises a backup unit for controlling the engine based only on the other cylinder identification signal when it is determined not to be normal internal combustion Engine control device.