JP2002276453A - Engine control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an engine control device capable of performing a cylinder discrimination at an early stage after detecting the starting of an engine. SOLUTION: When a crank angle signal NE is detected to be a missing tooth signal K first after detecting starting of the engine by a starter signal STA in an engine device (t2), a value (hereinafter referred to as a count value) CNT of a crank counter is initially set to a count start value according to a logic level of a signal G for cylinder discrimination at the time, and subsequently the count value CNT is updated every 30 deg. CA based on the crank angle signal NE and is revolved in the range of 0 to 23 corresponding to 720 deg. CA. In this device, a processing for performing the cylinder discrimination of the engine based on the count value CNT is started from a point of time (t2) when the count value CNT is initially set to the count start value. Therefore, the cylinder discrimination can be performed at the early stage and controllability of the engine can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine control device for controlling a four-stroke engine, and more particularly to a cylinder discrimination of an engine.

[0002]

2. Description of the Related Art Generally, in an engine control device for controlling an engine, as shown in FIG. 10, a crank angle signal (also referred to as a rotation signal) NE output from a crank angle sensor 1 in response to rotation of a crank shaft of the engine. And a cylinder discrimination signal G output from the cam angle sensor 2 according to the rotation of the camshaft of the engine that rotates at a ratio of 1/2 to the rotation of the crankshaft. The signal processing circuit 3 generates various signals NE2, TDC, and G2 for cylinder discrimination from the two signals NE and G and outputs the signals to a microcomputer (hereinafter referred to as a CPU) 4. The CPU 4 The engine is controlled by performing cylinder discrimination based on the signals NE2, TDC, and G2 from the third engine.

A conventional example of a cylinder discriminating method using an electromagnetic pickup (MPU) sensor as a cam angle sensor will be described with reference to FIG. First,
In this example, the crank angle signal NE output from the crank angle sensor indicates that the crankshaft is at 10 ° when the rotational position of the crankshaft is not one specific preset position.
A pulse signal having a period of one rotation is a pulse signal. When the rotational position of the crankshaft reaches a specific position, a missing tooth signal K having a period of 30 ° rotation of the crankshaft is one period.
That is, the crank angle signal NE changes from low level to high level every time the crankshaft rotates 10 ° (every 10 ° CA).
While changing in a pulse form like a low level,
When the rotational position of the crankshaft reaches the specific position, the interval of the rise becomes three times longer, and the period of the three times longer becomes the missing tooth signal K. The missing tooth signal K is generated every time the crankshaft makes one rotation (every 360 ° CA).

In this example, a cylinder discriminating signal G output from an MPU-type cam angle sensor indicates that the camshaft is one.
Each time the crankshaft rotates (i.e., every two rotations of the crankshaft), and the crank angle signal NE becomes the missing tooth signal K and the rotation angle of the crankshaft becomes 10 ° C.
From the timing of returning to the pulse signal for each A,
During a period (a period of 120 ° CA) until the motor rotates by 20 °, the pulse changes in a state of low level → high level → low level.

Next, in the engine control device, the signal processing circuit includes a crank angle signal NE and a cylinder discriminating signal G, and a starter signal STA which becomes a high level when a starter switch for starting the engine is turned on.
Based on the above, the following operations [S1-1] to [S1-4] are performed.

[S1-1]: First, as shown at time t1 in FIG. 11, when the starter signal STA becomes high level (when the starter switch is turned on), the signal processing circuit generates the signal in the crank angle signal NE. The detection operation of the missing tooth signal K (that is, the operation of detecting that the crank angle signal NE has become the missing tooth signal K) is started.

[S1-2]: As shown after time t2, when it is first detected that the crank angle signal NE has become the missing tooth signal K, the crank angle signal NE is frequency-divided thereafter. The period in which the crankshaft rotates 30 ° is defined as one cycle (in other words, every time the crankshaft rotates 30 ° (30
Rises at every CA) 30 as the second pulse signal
A CA signal NE2 is generated, and the 30 ° CA signal NE2 is generated.
Is output to the CPU, and a period corresponding to a predetermined cycle of the 30 ° CA signal NE2 (in this example, a period corresponding to four cycles and a period corresponding to 120 ° CA) after the detection of the missing tooth signal K is
This is set as a determination section HK for determining whether or not the cylinder determination signal G from the cam angle sensor rises.

The reason why such a determination section HK is provided is that the time difference between the timing at which the missing tooth signal K is generated and the timing at which the cylinder discrimination signal G rises is determined by the individual difference of the sensor, the change with time, or furthermore. This is because the operation is not always constant by controlling the cam shaft to change the opening / closing timing of the intake / exhaust valve.

[S1-3]: As shown at times t2 ', t3', t4 ',..., T7' in FIG.
A reference position signal TDC having an active level (low level in this example) for A is generated, and the reference position signal TDC is output to the CPU. Therefore, when the rotational position of the crankshaft comes to the reference position which is advanced by 120 ° from the specific position where the missing tooth signal K is generated, the reference position signal TDC is 3
It becomes low level for 0 ° CA.

[S1-4]: Further, the signal processing circuit generates a second cylinder discriminating signal G2 whose level is inverted every time the reference position signal TDC becomes an active level by the following procedure, and Output to That is, the signal processing circuit sets the second cylinder discriminating signal G2 to the low level in the initial state, and sets the cylinder discriminating signal G2 in the discrimination section HK.
Rises at the falling timing of the reference position signal TDC at the end of the determination section HK.
The cylinder determination signal G2 is set to a high level (see times t2 ', t4', and t6 'in FIG. 11), and conversely, the determination section HK
If the cylinder discrimination signal G does not rise within
At the falling timing of the reference position signal TDC at the end of the determination section HK, the second cylinder determination signal G2 is set to a low level (time t3 ', t5', t in FIG. 11).
7 ').

On the other hand, in the engine control device, the CPU
Is the starter signal ST as shown at time t1 in FIG.
When A becomes high level, the value (count value) CNT of the internal crank counter is set to −1, and thereafter, every time the 30 ° CA signal NE2 from the signal processing circuit rises, the following [ C1-1] to [C1-4]
The value CNT of the crank counter is updated in the procedure described above. still,
The value CNT of the crank counter indicates the cumulative rotation angle for two rotations of the crankshaft, with a resolution of 30 ° corresponding to the cycle of the 30 ° CA signal NE2, and is a value from 0 to 23 in this example. .

[C1-1]: If the reference position signal TDC from the signal processing circuit is at a high level and the current value CNT of the crank counter is smaller than 0 (that is, -1)
), Without changing the value CNT of the crank counter,
The process ends as it is. [C1-2]: Reference position signal TDC from signal processing circuit
Is at a high level and the current value CNT of the crank counter is 0 or more, the value CN of the crank counter
T is incremented by one (+1).

[C1-3]: On the other hand, if the reference position signal TDC from the signal processing circuit is at a low level, the logic level of the second cylinder discriminating signal G2 from the signal processing circuit is read and read. If the logic level of the second cylinder discrimination signal G2 is high, the value CNT of the crank counter is forcibly initialized to zero.

[C1-4]: If the reference position signal TDC from the signal processing circuit is at a low level and the logical level of the second cylinder discrimination signal G2 is also at a low level,
The current value CNT (current value) of the crank counter is 0 to 2
It is determined whether or not the current value is smaller than 12, which is an intermediate value of 3. If the current value is smaller than 12, the value CNT of the crank counter is set to 12, and if the current value is 12 or more, the value CNT of the crank counter is changed. Is corrected to zero.

That is, the CPU receives the signal from the signal processing circuit.
Each time the CA signal NE2 rises, the value CNT of the crank counter is updated according to the rules shown in Table 1 below. In Table 1 and other tables described later, CNT (n-1) is the value (current value) of the crank counter before updating in the current process.
CNT (n) indicates the value of the new crank counter (current value) updated in the current process. “L” indicates a low level, and “H” indicates a high level.

[0016]

[Table 1]

For this reason, as shown from time t2 to t2 'in FIG. 11, if the cylinder discriminating signal G rises in the first judgment section HK after the starter signal STA becomes high level, the judgment section At time t2 'at which HK ends, the reference position signal TDC from the signal processing circuit to the CPU goes low, the second cylinder discrimination signal G2 goes high, and the CPU sets the value C of the crank counter.
NT is initialized to 0.

Thereafter, in the CPU, the value CNT of the crank counter is counted up from 0 → 1 → 2 → 3..., As shown at time t3 ′, following the generation of the next missing tooth signal K. At the end timing of the determination section HK,
The second cylinder discrimination signal G2 from the signal processing circuit is output at time t.
At the time t3 ', the low level is opposite to 2'.
Then, a correction process for setting the value CNT of the crank counter to 12 is performed.

Further, as shown at time t4 ', at the end timing of the determination section HK following the generation of the missing tooth signal K, the second cylinder discriminating signal G2 becomes a high level opposite to the time t3'. Therefore, at time t4 ', the value CNT of the crank counter is initialized to 0, and thereafter, the same operations as those from time t2' to time t4 'are repeated, as shown after time t4' in FIG. .

Then, the CPU determines the cylinder to be ignited based on the value of the value CNT of the crank counter rotated in this way. As a specific example, if the engine is an in-line four-cylinder engine, for example, when the value CNT of the crank counter is 0, it is determined that the first cylinder # 1 is before the top dead center (BTDC) 30 ° CA, and the crank is determined. When the counter value CNT is 6, the BTDC of the second cylinder # 2 is 30 ° C.
When the crank counter value CNT is 12, it is determined that the BTDC is 30 ° CA for the third cylinder # 3, and when the crank counter value CNT is 18, it is determined that the BTDC is 30 ° CA for the fourth cylinder # 4. .

Note that the CPU first sets the reference position signal TDC =
The reason why the crank counter value CNT is initialized to 0 each time the same condition is satisfied not only when it is detected that the signal G2 is low and the second cylinder determination signal G2 is high, Even if the value CNT of the crank counter increases or decreases from the normal value due to the influence of noise or the like, the value can be promptly returned to the normal value. Also,
When the CPU detects that the reference position signal TDC = low and the second cylinder discriminating signal G2 = low, the value of the crank counter CNT is changed according to the value at that time (for details, 1
The correction to 0 or 12 (depending on whether or not it is 2 or more) is because even if several 30 ° CA signals NE2 from the signal processing circuit to the CPU are lost due to the influence of noise, etc. This is because the value CNT can be returned to a normal value.

On the other hand, in recent years, the direction of adopting a magnetoresistive element (MRE) type sensor in which an output level changes between a high level and a low level in accordance with the rotational position of a cam shaft as a cam angle sensor has been shifted to a direction of adopting. I have. Therefore, next, a conventional example of a cylinder discrimination method using an MRE-type sensor as a cam angle sensor will be described with reference to FIG.

First, in the example of FIG. 12, the crank angle signal NE output from the crank angle sensor is the same as that of FIG. 11, but the cylinder discrimination signal G output from the MRE type cam angle sensor is , According to the rotation position of the camshaft,
The logic level is inverted once during the period when the crank angle signal NE from the crank angle sensor is a pulse signal. For this reason, the cylinder discriminating signal G has a period in which the crankshaft makes two rotations (a period of 720 ° CA) as one cycle, and at a timing when the crank angle signal NE becomes the missing tooth signal K, it is alternately performed at each timing. Different logic levels.

Next, in the engine control device, the signal processing circuit performs the following [S] based on the crank angle signal NE, the cylinder discriminating signal G, and the starter signal STA.
2-1] to [S2-4] are performed. [S2-1]: First, even when the MRE-type cam angle sensor is used, the signal processing circuit detects a missing tooth in the crank angle signal NE when the starter signal STA rises as shown at time t1 in FIG. The detection operation of the signal K is started.

[S2-2]: Also in this case, when the signal processing circuit first detects that the crank angle signal NE has become the missing tooth signal K, as shown after time t2 in FIG. Thereafter, the frequency of the crank angle signal NE is divided to 30
30 ° C as the second pulse signal rising every ° CA
A signal NE2 is generated, and the 30 ° CA signal NE2 is
Output to PU.

[S2-3]: As shown at time t2 ', t3', t4 ',..., T7' in FIG. Each time a period of a predetermined period (in this example, a period of four cycles and a period of 120 ° CA) elapses, the reference position signal becomes an active level (low level in this example) by 30 ° CA A TDC is generated and its reference position signal TD
C is output to the CPU. Therefore, even in this case, the CPU
The reference position signal TDC goes to a low level by 30 ° CA when the rotational position of the crankshaft reaches a reference position advanced by 120 ° from the specific position where the missing tooth signal K is generated.

[S2-4]: Further, the signal processing circuit generates a second cylinder discriminating signal G2 whose level is inverted every time the reference position signal TDC becomes an active level by the following procedure, and Output to That is, first, the signal processing circuit sets the second cylinder discrimination signal G2 to the low level in the initial state, and as shown by the mark “○” in FIG. 12, the crank angle signal NE changes to the missing tooth signal K. The logic level of the cylinder discrimination signal G is read each time it is detected that Then, the signal processing circuit calculates the times t2 ′, t2 in FIG.
3 ', t4',..., T7 ', the reference position signal T
At each DC falling timing, the second cylinder discriminating signal G2 is set to a level opposite to the logical level of the cylinder discriminating signal G read at the time of detecting the missing tooth signal K immediately before the timing (FIG. 12). ).

Therefore, in the example of FIG. 12, the reference position signal TDC output from the signal processing circuit to the CPU and the second
The cylinder discrimination signal G2 changes in the same manner as in the case where the MPU cam angle sensor is used (FIG. 11). Then, in the engine control device, when the starter signal STA rises as shown at time t1 in FIG. 12, the CPU sets the value (count value) CNT of the internal crank counter to −1, and thereafter, the signal The same procedure as [C1-1] to [C1-4] described above when using the MPU-type cam angle sensor is performed by the process that is started each time the 30 ° CA signal NE2 from the processing circuit rises (that is, Table 1). The value CNT of the crank counter is updated according to the rule of (2). still,
Also in this case, the value CNT of the crank counter is
The resolution indicates the cumulative rotation angle for two rotations of the crankshaft, which is 30 ° corresponding to the cycle of the 30 ° CA signal NE2, and takes a value from 0 to 23.

Therefore, as shown at time t2 in FIG. 12, if the cylinder discriminating signal G is at the low level at the first generation of the missing tooth signal K after the starter signal STA goes to the high level. At time t2 ', which is 120 ° CA after that time, the reference position signal TDC from the signal processing circuit to the CPU goes low and the second cylinder discrimination signal G2 goes high, and the CPU The value CNT of the crank counter is obtained by the processing of [C1-3].
Is initialized to 0.

Thereafter, in the CPU, the value CNT of the crank counter is set to 30 ° CA from the signal processing circuit.
Each time the signal NE2 rises, it is counted up from 0 → 1 → 2..., And as shown at time t3 ′, the reference position signal T
When DC = low and the second cylinder discrimination signal G2 = low, the value CNT of the crank counter is set to 12 or 0 according to the current value at that time by the above process [C1-4].
(12 in the example of FIG. 12), and thereafter, at time t
As shown at 4 ', when the reference position signal TDC becomes low and the second cylinder discrimination signal G2 becomes high again, the value CNT of the crank counter is initialized to 0 by the process of [C1-3].

Thereafter, as shown at and after time t4 'in FIG. 12, the same operations as those from time t2' to time t4 'are repeated. Then, the CPU determines the cylinder to be ignited based on the value of the value CNT of the crank counter, as in the case where the MPU cam angle sensor is used.

[0032]

By the way, in each of the conventional engine control devices described with reference to FIGS.
There is a disadvantage that it is not possible to discriminate the cylinder early from the start of the engine.

That is, after the starter switch is turned on and the starter signal STA rises, even if the missing tooth signal K is first generated in the crank angle signal NE, the reference position signal TDC falls from that point at 120 °. Until the timing after the CA, the value CNT of the crank counter is not determined, and accordingly, the start of the count operation of the crank counter is delayed and the start of the cylinder determination is delayed.

Therefore, in the conventional engine control device,
There has been a limit in improving the controllability of the engine (particularly, the performance of the start control). Therefore, an object of the present invention is to provide an engine control device capable of performing the cylinder discrimination at an early stage from the time of detecting the start of the engine.

[0035]

According to a first aspect of the present invention, there is provided an engine control apparatus according to the first aspect of the present invention, wherein a first signal according to rotation of a crankshaft of an engine is provided. A crank angle signal output from the output means and a cylinder discriminating signal output from the second signal output means according to the rotation of the rotating shaft rotating at a ratio of 1/2 with respect to the rotation of the crankshaft are input. You.

The crank angle signal output from the first signal output means includes a period in which the crankshaft rotates by a predetermined unit angle for one cycle when the rotational position of the crankshaft is not one specific preset position. When the rotation position of the crankshaft comes to the specific position, the pulse signal becomes a missing tooth signal in which a period during which the crankshaft rotates by a predetermined angle larger than the unit angle is one cycle. Also, the second
Cylinder discrimination signal output from the signal output means of the above, when the logic level changes during the period when the crank angle signal is a pulse signal, at the timing when the crank angle signal becomes a missing tooth signal, The logic level is alternately different for each timing.

Furthermore, the engine control device of the present invention
A counter (so-called crank counter) whose count value indicates the cumulative rotation angle for two rotations of the crankshaft, and count control means for repeatedly circulating the count value of the counter are provided. The count control means detects the start of the engine, and when it detects that the crank angle signal first becomes a missing tooth signal after detecting the start of the engine, it counts the count value of the counter to the cylinder at that time. The logic level of the discrimination signal (that is, the logic level of the cylinder discrimination signal read when the crank angle signal is first detected as a missing tooth signal after the start of the engine is detected. (A detection level).

Specifically, when the detection level is low immediately after the start, the count control means initializes the count value of the counter to the first count start value, In the case where the detection level immediately after the start is high, the count value of the counter is changed from the first count start value by a value corresponding to one rotation of the crankshaft (360 ° CA). Initially set to the counting start value of

Further, after initially setting the count value of the counter to the count start value, the count control means updates the count value of the counter based on the crank angle signal and corresponds to two revolutions of the crankshaft. Loop around the value range. Specifically, based on the crank angle signal, it is detected that the crankshaft has rotated by an angle corresponding to the resolution of the count value of the counter, and the count value of the counter is incremented or decremented at each detection.

The engine control device of the present invention determines the cylinder of the engine based on the count value of the counter. The process for determining the cylinder is performed by the count control means using the count value of the counter as the count start value. Initially set (ie, when the crank angle signal becomes the missing tooth signal for the first time after the start of the engine is detected by the count control means)
Start with.

That is, the cylinder discriminating signal output from the second signal output means is the same as the cylinder discriminating signal G illustrated in FIG. At each timing, the logic level is alternately different at each timing. Therefore, the logic level of the cylinder discrimination signal when the crank angle signal becomes the missing tooth signal indicates that one cycle of the engine takes one cycle. The rotation position of the crankshaft (specifically, a rotation angle position, hereinafter also referred to as a crank angle) can be specified.

Therefore, in the engine control device of the present invention,
When it is first detected that the crank angle signal has become the missing tooth signal after detecting the start of the engine (at time t2 in FIG. 12).
At a time corresponding to the logical level of the cylinder discriminating signal at that time, a value corresponding to the crank angle specified from the logical level is set in the counter as a count start value,
Further, from the time of the setting, the cylinder discriminating process based on the count value of the counter is performed.

Therefore, according to the engine control apparatus of the present invention, the count value of the counter is determined and the cylinder discrimination is started from the timing when the crank angle signal becomes the missing tooth signal after the start of the engine is detected. can do.
Therefore, the cylinder discrimination can be performed earlier than the conventional device from the time when the start of the engine is detected, and as a result, the controllability of the engine (particularly, the performance of the start control) can be improved.

In this type of engine control device, generally, control processing for each cylinder of the engine is selectively switched according to the count value of a crank counter corresponding to the counter in the present invention. Configured to execute. In this case, the timing of switching from the execution period of the control process for one of the cylinders to the execution period of the control process for the other cylinder is the timing at which the crank angle signal becomes a missing tooth signal (hereinafter also referred to as missing tooth timing). Instead, it is often set based on the timing at which the crankshaft is rotated by a predetermined constant angle from the missing tooth timing.

Also, in the engine control apparatus of the present invention, as in the conventional apparatus described with reference to FIG. 12, every time that a specific crank angle is detected based on the crank angle signal, the count value of the counter is incremented. Is set to a normal value corresponding to the specific crank angle (corresponding to the above-described initialization or correction process). That is, even if the count value of the counter deviates from a normal value due to the influence of noise or the like, it can be returned to a normal value.

Here, the control process for each cylinder is selectively switched and executed according to the count value of the crank counter, and the switching timing of the execution period of each control process is different from the missing tooth timing. When the normalization process is performed at each missing tooth timing when the reference value is set as a reference, when the count value of the crank counter is shifted due to the influence of noise or the like, the control for each cylinder is performed. There is a disadvantage that the period during which processing cannot be executed normally becomes relatively long.

A specific example will be described. First, for example, in the engine control device described with reference to FIG.
PU is a value of a crank counter C as shown in FIG.
During a period in which NT is 0 to 5, a learning process regarding ignition of the first cylinder # 1 (for example, a signal is read from a knock sensor of a corresponding cylinder among knock sensors provided for each cylinder, and ignition of the cylinder is performed) (A control process of learning and calculating the correction value of the timing, etc.), and the value CNT of the crank counter is 6 to 1
During the period of 1, the learning process relating to the ignition of the second cylinder # 2 is executed. During the period when the value CNT of the crank counter is 12 to 17, the learning process relating to the ignition of the third cylinder # 3 is executed, and the value of the crank counter is determined. During the period when CNT is 18-23,
It is assumed that a learning process regarding the ignition of the cylinder # 4 is executed.

That is, in this example, the switching timing of the execution period of the control process for each cylinder is set to a timing 120 ° CA after the missing tooth timing (reference position signal TDC
Is set to a low level). FIG. 13 shows the same situation as the lower part of FIG.

In this example, as illustrated in FIG. 14, it is assumed that low-level noise has occurred in the cylinder discrimination signal G at the time tn of the missing tooth timing corresponding to the time t5 in FIG. Then, 120 ° from the time tn
At the falling timing of the reference position signal TDC after the CA, the second cylinder discriminating signal G2 remains at the high level due to the operation of [S2-4] described above, and as a result, the value CNT of the crank counter becomes the aforementioned value CNT. Due to the initialization of [C1-3], it is erroneously set to 0. And
The value CNT of the crank counter is originally 12, 13,.
.. 11 should be counted up to 23, and at the next falling timing of the reference position signal TDC, the above [C1-3] is initialized to a correct value of 0. Will be returned.

Therefore, in this case, at time tn in FIG.
A period of 360 ° CA from the falling timing of the reference position signal TDC after 120 ° CA to the next fall of the reference position signal TDC (the period described as “erroneous learning” in FIG. 14). Therefore, during the period in which the learning process for the third cylinder # 3 and the learning process for the fourth cylinder # 4 should be performed sequentially, the learning process for the first cylinder # 1 and the learning process for the second cylinder # 2 are incorrect. Will be implemented.

On the other hand, as a normalization process for the value CNT of the crank counter, instead of the above-described initialization process of [C1-3] and the correction process of [C1-4], for example, the crank angle signal NE is converted to the missing tooth signal. If the logical level is low in accordance with the logical level of the cylinder discriminating signal G at the time when this is detected, the value CNT of the crank counter is forcibly set to 20. If the logic level is high, the same operation as in FIG. 13 can be obtained by performing processing such as forcibly setting the value CNT of the crank counter to 8.

However, in the case of such a configuration, as shown in FIG. 15, it is assumed that low-level noise is generated in the cylinder discrimination signal G at the time tn of the missing tooth timing corresponding to the time t5 in FIG. Then, the value CN of the crank counter
T is erroneously set to 20 at that time tn, and then
Until the value is set to 20 at the next missing tooth timing, the count is incremented in a state of being out of the normal value.

Then, in this case, at time tn in FIG.
During the period of 360 ° CA from the first tooth missing timing to the next missing tooth timing (the period described as “erroneous learning” in FIG. 15), the fourth cylinder #
The learning process for the first cylinder # 1, the learning process for the first cylinder # 1, and the learning process for the second cylinder # 2 are not only erroneously performed, but also the second cylinder # 2 that was normally performed immediately before the time tn. Learning process is terminated in a halfway, and the fourth tooth missing timing at time tn
The learning control for cylinder # 4 is started halfway.

That is, in the normal state, if the normalization process is performed for the count value at each missing tooth timing, the control process for each cylinder is appropriately performed as can be seen from the comparison between FIG. 14 and FIG. That is, the period during which it cannot be performed becomes longer.

Therefore, in the engine control apparatus according to the first and second aspects, the apparatus executes control processing for each cylinder of the engine by selectively switching the cylinder according to the count value of the counter. The reference timing at which the crankshaft is rotated by a predetermined fixed angle after the crank angle signal becomes the missing tooth signal is controlled from the period during which the control process for any one of the cylinders is executed. If it is time to switch to the period in which the process is executed, it is preferable that the count control means is configured as described in claim 3.

That is, after the count control means initializes the count value of the counter to the count start value, the reference timing (when the crank angle signal becomes the missing tooth signal, the crank angle signal becomes (When the crankshaft rotates by a predetermined constant angle), the normalization process for setting the count value of the counter to a normal value corresponding to the reference timing is performed. is there.

With this configuration, when the count value of the counter deviates from a normal value due to the influence of noise or the like, the execution state (execution order and execution period) of the control process for each cylinder is changed. It is possible to return the count value of the counter to a normal value while minimizing the influence.

Note that the normalization processing is performed as described in [C1
-3], the count value of the counter may be set unconditionally, or as in [C1-4] described above,
The value of the counter may be set according to the current value. In other words, the normalization process may be any process that resets the count value of the counter to a value considered to be a normal value separately from the normal count.

[0059]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An engine control device according to an embodiment of the present invention will be described below with reference to the drawings. First, FIG. 1 is a configuration diagram illustrating a configuration of an engine control device (hereinafter, referred to as an ECU) 10 according to the first embodiment.
The ECU 10 controls, for example, an in-line four-cylinder four-cycle engine, and controls the engine by driving the fuel injection valves 11 to 14 and the ignition coils 21 to 24 corresponding to the four cylinders, respectively. And this ECU 10
Performs cylinder discrimination in substantially the same manner as in FIG.

As shown in FIG. 1, the ECU 10 includes a CPU (microcomputer) 31 for performing various processes for controlling the engine, and input buffers 33, 35, and 37.
, An A / D converter 39, an output buffer 41, and a signal processing circuit 43. The crank angle signal NE output from the crank angle sensor 47 attached to the engine is input to the signal processing circuit 43 via the input buffer 33, and is output from the cam angle sensor 49 attached to the engine. The cylinder discrimination signal G is input to the signal processing circuit 43 via the input buffer 35.

Here, the crank angle sensor 47 corresponds to a first signal output means, and is provided to face a rotor 47a fixed to the crankshaft of the engine and an outer periphery of the rotor 47a. 10 on the outer circumference of the rotor 47a
A signal output unit 47b of a photoelectric type or a Hall IC type that detects a tooth formed at an interval of ° CA and outputs a pulse signal. The outer periphery of the rotor 47a is provided with a toothless portion having two missing teeth.

Therefore, as shown in FIG. 12, the crank angle signal NE input from the crank angle sensor 47 to the signal processing circuit 43 via the input buffer 33 is changed every time the crankshaft rotates 10 ° ( At 10 ° CA), the pulse changes in a pulse form such as low level → high level → low level, and the rotational position of the crankshaft is changed to one specific position corresponding to the missing tooth portion of the rotor 47a (that is, the position of the rotor 47a). (Position where the missing tooth part faces the signal output part 47b)
, The interval between rises is three times longer. A portion that changes in a pulse shape every 10 ° CA becomes a pulse signal, and a period in which the rising interval is tripled (that is, the pulse signal is lost twice) occurs every 360 ° CA. The period is the missing tooth signal K (see FIGS. 2 and 4).

The cam angle sensor 49 corresponds to a second signal output means, and includes a rotor 49a fixed to a camshaft of an engine which rotates at a ratio of 1/2 to the rotation of the crankshaft; In accordance with the rotation of the rotor 49a, every time the rotor 49a makes a half turn (that is, 360 ° CA
And a signal output section 49b having a magnetoresistive element (MRE) for outputting a cylinder discriminating signal G whose logic level is inverted each time.

The cylinder discriminating signal G input from the cam angle sensor 49 to the signal processing circuit 43 via the input buffer 35 is a pulse signal output from the crank angle sensor 47 as shown in FIG. The logic level is inverted once during this period, and at the timing when the above-described missing tooth signal K is output from the crank angle sensor 47, the logic level becomes alternately different at each timing.

On the other hand, the CPU 31 in the ECU 10 receives a starter signal STA which goes high when the starter switch 51 for starting the engine is turned on, and an idle switch 53 which is turned on when the accelerator pedal is fully closed. Various switch signals indicating the operation state of the engine, such as signals, are input via the input buffer 37.

Further, the CPU 31 receives signals from various sensors such as an air flow meter 55 for detecting an intake air amount, a throttle sensor 57 for detecting a throttle operation amount, and a water temperature sensor 59 for detecting a cooling water temperature. D
It is input via a converter 39.

The signal processing circuit 43 also receives a starter signal STA from the input buffer 37. The signal processing circuit 43 converts the starter signal STA into the starter signal STA, the crank angle signal NE and the cylinder discrimination signal G. On the basis of,
According to the procedure described later, the 30 ° CA signal NE2 as the second pulse signal rising every 30 ° CA and the rotational position of the crankshaft are set at 120 from the specific position where the missing tooth signal K is generated.
The reference position signal TDC which becomes the active level (low level in the present embodiment) by 30 ° CA when it comes to the advanced reference position, and the second level is inverted every time the reference position signal TDC becomes the active level. Cylinder identification signal G
2 is generated and output to the CPU 31.

Then, the CPU 31 executes the signal processing circuit 43
Cylinder determination based on the signals NE2, TDC, and G2 output from the controller, and based on the determination result, the various switch signals, and the signals from the various sensors,
The optimum ignition timing, fuel injection timing, injection amount, and the like of the engine are calculated, and based on the calculation results, the fuel injectors 11 to 14 of each cylinder are driven via the output buffer 41 and the igniter 61 is driven. To energize the ignition coils 21 to 24 of the predetermined cylinder.

Next, the signal processing circuit 43 detects a missing tooth signal K from the crank angle sensor 47 (that is, the missing tooth signal K from the crank angle signal NE). 63, a level reading unit 65 that reads the logical level of the cylinder discrimination signal G from the cam angle sensor 49 when the occurrence of the missing tooth signal K is detected by the missing tooth detection unit 63, and a crank angle signal NE. 30 ° CA signal NE
And a discriminating signal generating section 69 for generating the reference position signal TDC and the second cylinder discriminating signal G2 in cooperation with the respective sections 63, 65, 67. I have.

As described above, the crank angle sensor 4
7, the missing tooth signal K is output when the missing tooth portion of the rotor 47a comes to a position facing the signal output portion 47b with the rotation of the crankshaft. Is also referred to as "missing tooth detection".

When the starter signal STA rises (when the starter switch is turned on), the missing tooth detecting section 63 determines that the engine has been started, and thereafter, according to the procedure shown in FIG. The missing tooth signal K in the signal NE is detected. That is, as shown in FIG. 2, each time the crank angle signal NE rises from a low level to a high level, the missing tooth detection unit 63 resets the timer value T2 for clocking to 0 and immediately before the resetting. From the timer value T2, the latest rising interval T1 of the crank angle signal NE is measured. Further, as shown by the one-dot chain line in FIG. 2, the rising interval T1 measured above is multiplied by N to set a threshold time (N × T1) for missing tooth signal detection.

In this embodiment, as described above, the missing tooth portion provided on the rotor 47a of the crank angle sensor 47 has two missing teeth, and the missing tooth signal K
Is a period in which the pulse signal for every 10 ° CA is lost twice, so that N is set to, for example, 2.5 between 2 and 3.

Then, when the timer value T2 exceeds the threshold time (N × T1), that is, at the time ta in the example of FIG. When it is detected that the crank angle signal NE does not rise even after the threshold time (N × T1) set at that time has elapsed from the rising timing, the crank angle sensor 47 outputs the missing tooth signal K. Therefore, the missing tooth detection signal FK is set to the high level for a certain period.

The missing tooth detection signal FK is returned to a low level, for example, when the crank angle signal NE falls next. Further, the rising of the missing tooth detection signal FK to the high level causes the level reading section 65, 30 ° C.
The A signal generation section 67 and the discrimination signal generation section 69 will know the generation of the missing tooth signal K.

Then, as shown in FIG. 2, when the missing tooth detection signal FK rises, the level reading section 65 outputs the cylinder discrimination signal G from the cam angle sensor 49 at that timing.
Is read, and the logical level (hereinafter, also referred to as a read level) Gr of the read cylinder determination signal G is stored. The reading level Gr is referred to by the determination signal generation unit 69, as described later.

Next, when the missing tooth detection signal FK first rises after the starter signal STA goes high, the 30 ° CA signal generation section 67 resets the value of the internal counter to 0.
Thereafter, every time the crank angle signal NE rises, the operation shown in the flowchart of FIG. 3 is performed to generate the 30 ° CA signal NE2.

That is, as shown in FIG. 3, when the crank angle signal NE rises, the 30 ° CA signal generation section 67 first increments the value of the internal counter by one (S1).
10) Then, it is determined whether or not the value of the internal counter has reached 34 (S120).

If the value of the internal counter is not 34 (S120: NO), the value of the internal counter is set to 3
It is determined whether the remainder obtained by dividing by 1 is 1 (S13).
0) If 1 (S130: YES), the 30 ° CA signal NE2 is set to the high level (S140). The remainder obtained by dividing the value of the internal counter by 3 is not 1 (S13).
0: NO), it is determined whether the remainder obtained by dividing the value of the internal counter by 3 is 0 (S150), and if it is 0 (S1).
50: YES), the 30 ° CA signal NE2 is set to low level (S160), and if not 0 (S150: NO), 3
The CPU waits for the next rising of the crank angle signal NE without changing the logic level of the 0 ° CA signal NE2.

On the other hand, if the value of the internal counter has reached 34 (S120: YES), the internal timer is set so that the 30 ° CA signal NE2 goes low after a certain time from that point (S170). , The value of the internal counter is returned to 0 (S180), and the 30 ° CA signal N
E2 is set to a high level (S140). Therefore, when the value of the internal counter is returned from 34 to 0, 30 ° CA
The signal NE2 changes from the low level to the high level, and returns to the low level after a predetermined time by the internal timer.

That is, as shown in FIG. 4, the 30 ° CA signal generator 67 counts up the value of the internal counter by one every time the crank angle signal NE rises, starting from the time when the missing tooth signal K is generated. In addition, when the value becomes 34, the value is returned to 0. Further, when the value of the internal counter is 1 to 33, the remainder of dividing the value of the internal timer by 3 is 1 or 2;
Is set to a high level, the 30 ° CA signal NE2 is set to a low level when the remainder obtained by dividing the value of the internal timer by 3 is 0, and when the value of the internal counter is returned from 34 to 0, 3
The 0 ° CA signal NE2 is set to a high level for a predetermined time by the internal timer.

The 30 ° CA signal generation section 67 divides the frequency of the crank angle signal NE by the above operation, and generates a 30 ° CA signal NE2 which is synchronized with the crank angle signal NE and rises every 30 ° CA. are doing. Next, when the starter signal STA rises, the discrimination signal generator 69 initializes the reference position signal TDC to the CPU 31 to a high level and initializes the second cylinder discrimination signal G2 to the CPU 31 to a low level. (See FIGS. 7 and 8).

Then, the discriminating signal generating section 69 thereafter
The process shown in the flowchart of FIG. 5 is performed at each rising timing of the 30 ° CA signal NE2 generated by the 30 ° CA signal generation section 67, thereby changing the levels of the reference position signal TDC and the second cylinder discrimination signal G2. . still,
In FIG. 5, G (n) is the latest reading level G of the cylinder discrimination signal G read this time by the level reading unit 65.
This is a 1-bit storage unit for storing r.

As shown in FIG. 5, the discriminating signal generator 69
When the 30 ° CA signal NE2 rises, first, at S21
At 0, by determining whether the missing tooth detection signal FK from the missing tooth detection unit 63 is at a high level, the missing tooth signal K in the crank angle signal NE is detected by the missing tooth detection unit 63. It is determined whether or not it is the missing tooth detection timing.

If it is determined that the missing tooth detection timing is reached, the logic level of the cylinder discriminating signal G is read by the level reading section 65 immediately before the 30 ° CA signal NE2 rises this time. In subsequent S220, the read level Gr of the cylinder discrimination signal G read this time by the level reading section 65 is stored in G (n).
Proceed to S230. If it is determined in S210 that it is not the missing tooth detection timing, the process proceeds to S230.
Move to

Next, the discriminating signal generator 69 proceeds to S230
At 30 ° C after the starter signal STA rises
The timing when the A signal NE2 first rises (that is,
After detecting the start of the engine based on the starter signal STA, the missing tooth detecting section 63 first detects the crank angle signal NE.
Is determined to be the missing tooth signal K), and if the determination is affirmative, it is immediately after the start of the engine in which the missing tooth signal K first occurs in the crank angle signal NE. It proceeds to S240. Then, in this S240, the second cylinder discrimination signal G2
Is set to the logic level within G (n), and the process is terminated.

On the other hand, the discrimination signal generator 69
If a negative determination is made at 30 that it is not immediately after the start of the engine, the flow shifts to S250, where it is determined whether or not it is time to set the reference position signal TDC to a low level (hereinafter referred to as TDC output timing). . It should be noted that whether or not it is the TDC output timing is determined by the 30 ° CA signal NE from when it is determined in S210 that it is the missing tooth detection timing.
The determination is made based on whether or not 2 is the timing of rising four times.

If it is determined that the timing is not the TDC output timing, the process is terminated as it is.
If it is determined that it is the output timing, the process proceeds to S260, where the reference position signal TDC to the CPU 31 is
It is kept at a low level until the CA signal NE2 rises next (that is, until the next processing start). Further, in the following S270, the output level of the second cylinder discriminating signal G2 to the CPU 31 is set to a level opposite to the logic level in G (n), and the process ends.

By the processing shown in FIG. 5, the logical level of the reference position signal TDC becomes 30 ° when the rotational position of the crankshaft comes to the reference position 120 ° ahead of the specific position where the missing tooth signal K is generated. It becomes low level for CA. When the missing tooth signal K is first generated in the crank angle signal NE after the starter signal STA rises, the logic level of the second cylinder discrimination signal G2 is the same as the logic level of the cylinder discrimination signal G at that time. After that, each time the reference position signal TDC goes low (hereinafter also referred to as reference timing), the logical level of the cylinder discrimination signal G read at the time of detection of the missing tooth immediately before the reference timing is set to Is set to the opposite level.

That is, in addition to the above-described operations of [S2-1] to [S2-4], the signal processing circuit 43 reads "start of the engine based on the starter signal STA.
When first detecting that the crank angle signal NE has become the missing tooth signal K, the second cylinder discrimination signal G2 is set to the same level as the logical level of the cylinder discrimination signal G read at that time. " By additionally performing the operation of S240 of No. 5, a reference position signal TDC and a second cylinder determination signal G2 are generated and output to the CPU 31.

For this reason, in the ECU 10 of the present embodiment, if the cylinder discrimination signal G is at the low level at the first missing tooth timing (timing when the crank angle signal NE becomes the missing tooth signal K) after the starter signal STA rises, If
As at time t2 in FIG. 7, the second cylinder discriminating signal G2 is set to the low level at that time, and the starter signal S
If the cylinder discrimination signal G is at the high level at the first missing tooth timing after the rise of TA, the second cylinder discrimination signal G2 is set to the high level at that time, as at time t2 in FIG. Becomes In FIG. 7, since the cylinder discrimination signal G is at low level at time t2, the second cylinder discrimination signal G2 remains at low level until time t2 'when the reference position signal TDC first falls. I have.

On the other hand, in the ECU 10 of the first embodiment, when the starter signal STA rises, the CPU 31 determines that the engine has been started, and changes the value (specifically, the count value) CNT of the internal crank counter to −.
1 and then 30 ° CA from the signal processing circuit 43.
Each time the signal NE2 rises, the processing of FIG. 6 is performed to update the value CNT of the crank counter.

In the present embodiment, the crank counter is actually a storage area set in the RAM (not shown) of the CPU 31 for storing the count value CNT. This crank counter corresponds to the counter in the present invention. Also in the present embodiment, the value CNT of the crank counter is equal to 2 of the crankshaft.
The cumulative rotation angle corresponding to the rotation is indicated by a resolution of 30 ° corresponding to the cycle of the 30 ° CA signal NE2, and is a value from 0 to 23.

As shown in FIG. 6, when the 30 ° CA signal NE2 from the signal processing circuit 43 rises, the CPU 31 firstly proceeds to S300 to read the current crank counter value C.
It is determined whether or not NT is smaller than 0. If it is smaller than 0 (that is, if −1), it is determined that it is the first missing tooth timing from the start of the engine, and the process proceeds to S305.
In this state, the reference position signal TDC from the signal processing circuit 43 is at a high level.

Then, in S305, the signal processing circuit 43
, The logical level of the second cylinder discriminating signal G2 is read, and it is determined whether or not the read logical level is a high level. If the logical level is not the high level (that is, if it is the low level), the process proceeds to S310. And the value of the crank counter C
NT is initially set to 20 as a first count start value, and the process is thereafter terminated. If it is determined in step S305 that the logical level of the read second cylinder determination signal G2 is high, the process proceeds to step S315, in which the value CNT of the crank counter is set as a second count start value. Is set to 8, and then the process is terminated. S30
The logical level of the second cylinder discriminating signal G2 read at 5 is, as is apparent from the operation of the signal processing circuit 43 described above, first after the start of the engine is detected based on the starter signal STA, and then the missing tooth detecting section is detected. This is the logical level of the cylinder discrimination signal G read by the level reading unit 65 when the occurrence of the missing tooth signal K is detected by 63 (corresponding to the detection level immediately after starting).

On the other hand, if it is determined in step S300 that the current value CNT of the crank counter is not smaller than 0 (that is, it is not smaller than 0), the flow shifts to step S320, and the reference position from the signal processing circuit 43 is determined. It is determined whether the signal TDC is at a low level. Here, when it is determined that the reference position signal TDC is not at the low level (that is, at the high level), it is not the reference timing advanced by 120 ° CA from the missing tooth timing. In step S330, it is determined whether the value CNT of the crank counter has reached 24 or more. If the value CNT of the crank counter is equal to or greater than 24, the process proceeds to S335.
Then, the process is terminated after returning the value CNT of the crank counter to 0, and when it is determined in S330 that the value CNT of the crank counter is not 24 or more, the process is terminated as it is.

At S320, the reference position signal T
If it is determined that DC is at the low level, the process proceeds to S340 because it is the reference timing, and the logic level of the second cylinder determination signal G2 from the signal processing circuit 43 is read. Then, in subsequent S345, it is determined whether or not the logic level G2 (n) of the second cylinder discrimination signal G2 read this time in S340 is low, and is not low (high). If it is determined that
Proceeding to S350, the value CNT of the crank counter is forcibly initialized to 0, and the process ends.

On the other hand, at S345, at S340
If it is determined that the logical level G2 (n) read this time is the low level, the process proceeds to S360, where the following correction processing of S360 to S370 for the value CNT of the crank counter is performed, and then the processing is terminated. .

In this correction process, first, in step S360, the current value CNT (current value) of the crank counter is set to 0 to 23.
It is determined whether or not the current value is 12 or more, which is the intermediate value of
If the current value is smaller than 12, the crank counter value CNT is set to 12 at S365.
In S370, the value CNT of the crank counter is set to 0.

That is, the CPU 31
Every time the 30 ° CA signal NE2 rises, the value CNT of the crank counter is updated according to the rules shown in Table 2 below.

[0100]

[Table 2]

Specifically, S300 and S320-S
By the process of 335, [C1-2] which is the same as [C1-2] described above.
2-2], and perform S320, S340, and S34.
5, and S350, the above-mentioned [C1-3]
The same process as [C2-3] is performed, and S320, S34
By the processes 0, S345, and S360 to S370, the same [C2-4] as [C1-4] described above is performed. Note that the processes of S330 and S335 are processes for guard that always set the value CNT of the crank counter to a value of 0 to 23.

In particular, the CPU 31 of the first embodiment
Then, by the processing of S300 to S315, [C
Instead of the processing of [1-1], the following startup processing of [C2-1] marked with “*” in Table 2 is performed. [C2-1]: The current value CNT of the crank counter is 0
If it is smaller than (ie, CNT = −1, in this case, the reference position signal TDC from the signal processing circuit 43 is always at a high level), it is the first missing tooth timing from the start of the engine. Then, the logic level of the second cylinder discrimination signal G2 is read, and if the read logic level of the second cylinder discrimination signal G2 is low, the value CNT of the crank counter is used as the first count start value. On the other hand, if the logic level of the second cylinder discrimination signal G2 is high, the value CNT of the crank counter is initialized to 8 as the second count start value.

Incidentally, 20 and 8 as the count start values initially set in the process for starting at [C2-1] are crank angles at the timing of missing teeth (crank angle with one cycle of the engine as one cycle). ), Which are different from each other by a value corresponding to one rotation of the crankshaft (360 ° CA). Therefore, the continuity of the value CNT of the crank counter is not impaired by the process [C2-1].

In the ECU 10 of the first embodiment, for example, as shown at time t2 in FIG. 7, the first missing tooth timing (timing of generating the missing tooth signal K) after the starter signal STA becomes high level. If the signal G for cylinder discrimination is at a low level, the signal G2 for cylinder discrimination from the signal processing circuit 43 to the CPU 31 is also at a low level.
With the start of the output of E2, the CPU 31 sets the above [C2-
By the process [1], the value CNT of the crank counter is initialized to 20.

Thereafter, in the CPU 31, FIG.
As shown in (3), the value CNT of the crank counter is changed from the signal processing circuit 43 by the process of [C2-2].
20 → 21 → 22 every time 0 ° CA signal NE2 rises
, And the reference position signal TDC = low and the second cylinder discrimination signal G2 as shown at time t2 '.
== High, the value CNT of the crank counter is initialized to 0 by the above process [C2-3]. Further, when the reference position signal TDC becomes low and the second cylinder discrimination signal G2 becomes low as shown at time t3 ', the value CN of the crank counter is obtained by the processing of [C2-4].
T is corrected to 12 or 0 (12 at time t3 ′ in FIG. 7) according to the current value at that time, and thereafter, as shown at time t4 ′, the reference position signal TDC = low and the second cylinder discrimination signal again When G2 = high, the value of the crank counter C
NT is initialized to 0 by the above process [C2-3]. Thereafter, as shown after time t4 'in FIG. 7, the same operation from time t2' to time t4 'is repeated, so that the value CNT of the crank counter circulates in the range of 0 to 23.

For example, as shown at time t2 in FIG. 8, if the cylinder discrimination signal G is at the high level at the first missing tooth timing after the starter signal STA has reached the high level, the signal processing circuit Since the second cylinder discrimination signal G2 from 43 to the CPU 31 also becomes high level, the CPU 31 starts the output of the 30 ° CA signal NE2 by the signal processing circuit 43, and the CPU 31 executes the process of [C2-1]. The value CNT is initialized to 8.

Thereafter, in the CPU 31, FIG.
As shown in (3), the value CNT of the crank counter is changed from the signal processing circuit 43 by the process of [C2-2].
Each time the 0 ° CA signal NE2 rises, the count is incremented from 8 → 9 → 10... When the reference position signal TDC = low and the second cylinder discrimination signal G2 = low as shown at time t2 ′, the above-described operation is performed. By the process of [C2-4], the value CNT of the crank counter is corrected to 12 or 0 (12 at time t2 'in FIG. 8) according to the current value at that time. Also, as shown at time t3 ', the reference position signal TDC =
When the signal becomes low and the second cylinder discrimination signal G2 becomes high, the value CNT of the crank counter is initialized to 0 by the processing of [C2-3], and thereafter, as shown at time t4 ', the reference position signal CNT is returned again. When TDC = low and the second cylinder discrimination signal G2 = low, the value of the crank counter CN
T is corrected to 12 or 0 (12 at time t4 'in FIG. 8) according to the current value at that time by the process of [C2-4]. Thereafter, as shown after time t4 'in FIG.
By repeating the same operation from time t2 'to time t4', the value CNT of the crank counter circulates in the range of 0 to 23.

Then, the CPU 31 determines the cylinder to be ignited based on the value CNT of the crank counter circulated in this way. The processing for determining the cylinder is carried out in S310 or S315 in FIG. When the value CNT is initialized to 20 or 8 (that is, the starter signal S
It starts from the first missing tooth timing from when the start of the engine is detected by the rise of TA. In this cylinder discriminating process, the cylinder to be ignited is discriminated in the manner described in the section of "Prior Art". For example, CNT = 0
BTDC of the first cylinder # 1 is determined to be 30 ° CA at
When NT = 6, the BTDC of the second cylinder # 2 is determined to be 30 ° CA, and when CNT = 12, the BTDC 30 of the third cylinder # 3 is determined.
° CA, and when CNT = 18, B of the fourth cylinder # 4
It is determined that TDC is 30 ° CA.

Further, as a control process for each cylinder, the CPU 31 ignites the first cylinder # 1 during the period in which the value CNT of the crank counter is 0 to 5 as in the conventional example described with reference to FIG. Learning process (in this embodiment,
Among the knock sensors provided for each cylinder, a signal is read from the knock sensor of the corresponding cylinder, and a control process of learning and calculating a correction value or the like of the ignition timing of the cylinder is executed.
During the period when the value CNT of the crank counter is 6 to 11, the second
A learning process regarding the ignition of the cylinder # 2 is executed, and during the period in which the value CNT of the crank counter is 12 to 17, the third cylinder # 3
The learning process relating to the ignition of the fourth cylinder # 4 is performed during the period in which the value CNT of the crank counter is 18 to 23. That is, in the ECU 10, the switching timing of the execution period of the control process for each cylinder is not the toothless timing, but the timing after 120 ° CA from the toothless timing (the reference timing when the reference position signal TDC becomes low level). Set as a reference.

In the above-described ECU 10 of the present embodiment, the cylinder discrimination signal G from the cam angle sensor 49 has a different logic level at each missing tooth timing, and the cylinder discrimination signal at the missing tooth timing is provided. Paying attention to the fact that it is possible to specify the crank angle with one cycle of the engine as one cycle by looking at the logical level of G, and after detecting the start of the engine by the rise of the starter signal STA, When it is detected that the angle signal NE has become the missing tooth signal K (corresponding to the time t2 in FIGS. 7 and 8), the crank angle corresponding to the crank angle specified from the logical level of the cylinder determination signal G at that time is detected. The count start value (20 or 8 in the present embodiment) is set in the crank counter, and from the time of setting, the cylinder discrimination based on the count value CNT of the crank counter is performed. So that to start the process.

Therefore, according to the ECU 10 of the present embodiment, the value CNT of the crank counter is determined at the first missing tooth timing after the start of the engine is detected by the rise of the starter signal STA, and the cylinder CNT is determined from that time. The determination can be started. Therefore, the cylinder discrimination can be performed earlier than the conventional device from the time when the start of the engine is detected, and the controllability of the engine (particularly, the performance of the start control).
Can be improved.

Further, in the ECU 10 of the present embodiment,
The switching timing of the execution period of the control process for each cylinder is not the toothless timing, but is 12
Since the value is set based on the reference timing after 0 ° CA, the value CNT of the crank counter is initially set to 20 or 8 in S310 or S315 in FIG. (In the present embodiment, the above [C2
The initialization of [-3] and the correction processing of [C2-4]) are performed not when the missing tooth is detected but every time when the reference timing is detected based on the crank angle signal NE.

For this reason, if the value CNT of the crank counter deviates from a normal value due to the influence of noise or the like, the incomplete control processing described with reference to FIG. 15 may occur. It is possible to return the crank counter value CNT to a normal value while minimizing the influence on the execution state (execution order and execution period) of the control processing for each cylinder as shown in FIG. become.

Note that in the first embodiment, the CPU 31
By the processing of FIG. 6, 30 ° CA from the signal processing circuit 43 is output.
Although the setting and updating of the value CNT of the crank counter are performed based on the signal NE2 and the second cylinder discriminating signal G2, the 30 ° CA signal NE2 and the second cylinder discriminating signal G2 are used.
Is a signal generated from the crank angle signal NE and the cylinder discriminating signal G.
The setting and updating of NT are performed based on the crank angle signal NE and the cylinder discrimination signal G. And
In the first embodiment, the signal processing circuit 43 and the CPU 31
(Particularly, the part that performs the processing of FIG. 6) corresponds to the count control means.

Next, an engine control unit (ECU) according to a second embodiment will be described. It should be noted that E of the second embodiment
The CU also includes the same components as those of the ECU 10 of the first embodiment shown in FIG. 1, and therefore, the same reference numerals as those in the first embodiment are used here for those components and each signal.

The ECU 10 of the second embodiment differs from the first embodiment in that the CPU 31 replaces the processing of FIG. 6 each time the 30 ° CA signal NE2 from the signal processing circuit 43 rises. The only difference is that the process of No. 9 is performed. Then, in the processing of FIG. 9, compared with the processing of FIG. 6, the processing of S360 and S370 is deleted. More specifically, the CPU 31 determines in S345 that the second cylinder discrimination signal G that has been read this time in S340.
If it is determined that the logical level G2 (n) of 2 is low level, the process directly proceeds to S365 and the value CNT of the crank counter is forcibly initialized to 12. In FIG. 9, the other steps have the same step numbers as in FIG.

That is, in the second embodiment, the CPU
31 is a crank counter if the second cylinder discrimination signal G2 is at a high level when the reference position signal TDC from the signal processing circuit 43 is at a low level, as shown in the column of "Initialization" in Table 3 below. Is forcibly initialized to 0 (S345: NO, S350). Conversely, if the second cylinder discrimination signal G2 is at a low level, the value CNT of the crank counter is forcibly initialized to 12. (S345: YES, S365).

[0118]

[Table 3]

Then, the EC according to the second embodiment is used.
The ECU 10 of the above-described first embodiment is also used by U10.
The same effect can be obtained. Also, according to the ECU 10 of the second embodiment, when the value CNT of the crank counter deviates from the normal value due to the influence of noise or the like, the value CNT of the crank counter CNT is at most within a period of 360 ° CA. Can be reliably returned to a normal value, which is advantageous. This corresponds to the timings corresponding to times t3 ', t5', t7 ',... In FIG. 7 or t2', t7 in FIG.
At each timing corresponding to 4 ′, t6 ′,..., Regardless of the current value of the crank counter,
This is because the initialization is forced to 2.

Note that, also in the second embodiment, the signal processing circuit 43 and the CPU 31 (particularly, a portion for performing the processing in FIG. 9) correspond to the count control means. As mentioned above, although one Embodiment of this invention was described, it cannot be overemphasized that this invention can take various forms.

For example, the present invention relates to an electromagnetic pickup (M
PU) -type cam angle sensor can be applied while retaining the concept of the determination section HK illustrated in FIG. 11 when the cam angle sensor is used. Specifically, when the missing tooth signal K is first detected after the start of the engine is detected, the value CNT of the crank counter is changed to a count start value (20 or 20) corresponding to the logical level of the cylinder determination signal G at that time. 8), and thereafter, as in the case of FIG.
Each time the reference timing after the CA arrives, the cylinder determination signal G rises depending on whether the cylinder determination signal G rises within the determination section HK from the missing tooth timing to the reference timing. Is to forcibly initialize the value CNT of the crank counter to 0, and perform a correction process of setting the value CNT of the crank counter to 12 or 0 according to the current value if the cylinder discrimination signal G does not rise. May be.

In each of the above embodiments, the period from the generation of the missing tooth signal K until the reference position signal TDC becomes the active level is a period of 120 ° CA. May be a period corresponding to a crank angle other than 120 ° CA. Furthermore, in each of the above embodiments, the case where the control target is a four-cylinder engine has been described as an example. However, the present invention is not limited to this. For example, a six-cylinder engine or an eight-cylinder engine may be used.

On the other hand, in each of the above embodiments, the cylinder discriminating signal G output from the cam angle sensor 49 is 360 ° CA
Although the level is inverted only once every time, the cylinder discriminating signal G only needs to have a different logic level alternately at each timing when the missing tooth signal K is output from the crank angle sensor 47. Alternatively, a signal whose level is inverted a plurality of times during the period when the pulse signal is output from the crank angle sensor 47 may be used.

In the signal processing circuit 43, the level reading section 65 outputs the missing tooth detection signal FK from the missing tooth detecting section 63.
The logical level of the cylinder discrimination signal G may be read at the timing when the crank angle signal NE first rises after the rise of the cylinder angle signal NE, that is, at time tb in FIG.

Further, in the ECU 10 of each of the above embodiments, the start of the engine is detected by the rise of the starter signal STA. However, the start of the engine is detected from information other than the starter signal STA. Is also good. For example, when the engine speed obtained from the cycle of the crank angle signal NE exceeds a predetermined start determination value, it can be determined that the engine has been started. In the case of this example, more specifically, the signal processing circuit 4
3 detects the start of the engine from the cycle of the crank angle signal NE, the starter signal STA in each of the above-described embodiments.
Works from the beginning, just like when
An instruction signal indicating the start of the engine is output to the CPU 31,
When receiving the instruction signal from the signal processing circuit 43, the CPU 31 sets the value CNT of the crank counter to −1 and thereafter sets the 30 ° CA signal N from the signal processing circuit 43.
The processing of FIG. 6 or 9 may be performed every time E2 rises.

In each of the above embodiments, the value CNT of the crank counter is counted up, but the value CNT of the crank counter may be counted down. Further, the range in which the value CNT of the crank counter circulates is not limited to 0 to 23, but may be, for example, 5 to 23.
28, 10 to 33, etc., can be set as appropriate. Also, the count start value is not limited to 20 and 8, and may be appropriately determined according to a range around the value CNT of the crank counter.

[Brief description of the drawings]

FIG. 1 is a configuration diagram illustrating a configuration of an engine control device according to a first embodiment.

FIG. 2 is a time chart illustrating operations of a missing tooth detection unit and a level reading unit in the signal processing circuit according to the first embodiment.

FIG. 3 is a view illustrating a configuration of 30 ° in the signal processing circuit according to the first embodiment.
5 is a flowchart illustrating an operation of a CA signal generation unit.

FIG. 4 shows a diagram illustrating a 30 ° angle in the signal processing circuit according to the first embodiment.
5 is a time chart illustrating an operation of a CA signal generation unit.

FIG. 5 is a flowchart illustrating an operation of a determination signal generation unit in the signal processing circuit according to the first embodiment.

FIG. 6 is a flowchart illustrating a process executed by a CPU according to the first embodiment.

FIG. 7 is a first time chart illustrating the operation of the first embodiment;

FIG. 8 is a second time chart illustrating the operation of the first embodiment;

FIG. 9 is a flowchart illustrating a process executed by a CPU according to the second embodiment.

FIG. 10 is a block diagram illustrating a general hardware configuration of an engine control device.

FIG. 11 is a time chart showing a cylinder discriminating operation performed by a conventional engine control device using an electromagnetic pickup (MPU) type cam angle sensor.

FIG. 12 is a time chart showing a cylinder discriminating operation performed by a conventional engine control device using a magnetoresistive element (MRE) type cam angle sensor.

FIG. 13 is an explanatory diagram illustrating an example of an execution order and an execution period of a control process for each cylinder.

FIG. 14 is a first diagram illustrating a problem that occurs when the normalization process for the count value of the crank counter is performed at each missing tooth timing.

FIG. 15 is a second diagram illustrating a problem that arises when the normalization process for the count value of the crank counter is performed at each missing tooth timing.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Engine control device (ECU), 11-14 ... Fuel injection valve, 21-24 ... Ignition coil, 31 ... Microcomputer (CPU), 33, 35, 37 ... Input buffer, 39 ... A / D converter, 41 … Output buffer, 43…
Signal processing circuit, 47: crank angle sensor, 49: cam angle sensor, 51: starter switch, 53: idle switch, 55: air flow meter, 57: throttle sensor, 59: water temperature sensor, 61: igniter, 63: missing tooth detection Section, 65: level reading section, 67: 30 ° CA signal generation section, 69: discrimination signal generation section

Claims (3)

[Claims] An output unit configured to output a signal from the first signal output unit in response to a rotation of a crankshaft of the engine when the rotation position of the crankshaft is not a predetermined specific position; A pulse signal having a period of one rotation period and a missing tooth signal having one period of rotation of the crankshaft by a predetermined angle greater than the unit angle when the rotation position of the crankshaft comes to the specific position. From the second signal output means, and 1 to the rotation of the crankshaft.
Output in accordance with the rotation of the rotating shaft rotating at a ratio of / 2,
When the logic level changes during the period in which the crank angle signal is a pulse signal, the cylinder discrimination in which the logic level alternately differs at each timing when the crank angle signal becomes the missing tooth signal is performed. And a counter whose count value indicates a cumulative rotation angle for two rotations of the crankshaft, and detecting the start of the engine and the crank angle first after detecting the start of the engine. When it is detected that the signal has become a missing tooth signal, the count value of the counter is initialized to a predetermined count start value corresponding to the logical level of the cylinder discrimination signal at that time, and thereafter, the count value of the counter is counted. Count control means for updating a value based on the crank angle signal and rotating the value in a range of values corresponding to two rotations of the crankshaft. The process of performing the cylinder discrimination of the engine based on the count value of the counter is configured to be started from a point in time when the count control unit initializes the count value to the count start value. Engine control device. 2. The engine control device according to claim 1, wherein the count control unit detects when the crank angle signal first becomes a missing tooth signal after the start of the engine is detected. If the logical level of the cylinder discrimination signal (hereinafter referred to as the detection level immediately after starting) is low, the count value of the counter is initialized to a first count start value, and the detection level immediately after starting is high. In the case of the level, the count value of the counter is initialized to a second count start value different from the first count start value by a value corresponding to one rotation of the crankshaft. Engine control device. 3. The engine control device according to claim 1, wherein the control device performs a control process for each cylinder of each cylinder of the engine in accordance with a count value of the counter. It is configured to switch to and execute
The reference timing at which the crankshaft is rotated by a predetermined constant angle after the crank angle signal becomes the missing tooth signal,
It is a switching timing from a period in which the control process for any one of the cylinders is performed to a period in which the control process for the other cylinder is performed, and further, the count control means sets the count value of the counter to the count start value. After the initial setting, when detecting that the reference timing has arrived based on the crank angle signal, performing a normalization process for setting the count value of the counter to a normal value corresponding to the reference timing. An engine control device characterized in that: