JP3409454B2 - Engine crank angle determination 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 engine crank angle determining device for determining a crank angle by determining a change in a pulse interval of a pulse signal generated according to rotation of a crank shaft of an engine.

[0002]

2. Description of the Related Art A conventional crank angle determining device has a detection gear fitted on a crankshaft of an engine, and a pickup is opposed to a tooth portion on the outer periphery of the detection gear so that the detection gear is not provided at a predetermined position on the outer periphery of the detection gear. By forming the tooth portion and making the pitch of the tooth portion in the other region equal pitch, while outputting the pulse signal of the equal interval from the pickup in the region other than the predetermined crank angle (position of the toothless portion), The pulse interval is lengthened at a predetermined crank angle (the position of the toothless portion), and the change in the pulse interval is detected to determine the crank angle. In this case, since the pulse interval also changes depending on the engine speed, for example, in the extremely low speed range, the interval between the tooth parts other than the missing part of the detection gear may be mistaken for a missing part, or conversely in the high speed range. Then, there arises a problem that the toothless portion cannot be detected.

In order to solve this drawback, conventionally, Japanese Patent Laid-Open Nos. 61-25017 and 61-14954 have been used.
6 and Japanese Patent Application Laid-Open No. 59-168317, the determination reference value for determining the toothless portion of the detection gear is switched between two stages at low rotation (or at startup) and high rotation. There is something like this.

[0004]

By the way, the number of revolutions of the engine is frequently changed, and the pulse interval is also changed due to the rotational change. When the rotational change is large, the change of the pulse interval is also large. Therefore, as in the above-described known example, if the determination reference value for determining the tooth-missing portion of the detection gear is switched between two stages in the low rotation range (or at the start) and the high rotation range, the engine rotation fluctuation is large. At times, the change in the pulse interval due to the rotation fluctuation causes a decrease in the detection accuracy of the toothless portion, as described above.

Further, even when the engine speed is low (or when the engine is started), fluctuations in rotation when the engine cooling water temperature is low and the battery voltage is low, and when the engine cooling water temperature is normal temperature and the battery voltage is high The magnitude of the rotation fluctuation is different from that of the rotation fluctuation, and naturally, the rotation fluctuation is larger in the case of. Therefore, even at low rotation (or at the time of starting), it is inherently impossible to uniformly determine the determination reference value of the toothless portion that simultaneously satisfies both of the above. However, in the above-mentioned known example, since the determination reference value of the toothless portion at low rotation (or at the time of starting) is uniformly set, both of the above cannot be satisfied at the same time.

The present invention has been made in consideration of the above circumstances, and therefore an object thereof is to provide a discrimination reference value for discriminating a change in pulse interval to an engine as compared with a conventional two-step switching system. It is an object of the present invention to provide an engine crank angle determination device that can be appropriately changed according to operating conditions (rotational fluctuation, battery voltage, engine cooling water temperature, etc.) and that can improve crank angle determination accuracy.

[0007]

In order to achieve the above object, an engine crank angle determining device according to claim 1 of the present invention generates pulse signals at equal intervals in response to rotation of a crank shaft of the engine. In the engine equipped with pulse signal generating means for changing the pulse interval at a predetermined crank angle and crank angle judging means for judging the crank angle based on the change of the pulse interval A configuration provided with a rotation fluctuation detecting means for detecting fluctuation, and a judgment reference value varying means for changing a judgment reference value for judging whether or not the pulse interval has changed according to a detection result of the rotation fluctuation detecting means. It was done.

In this case, the rotation fluctuation detecting means may detect the rotation fluctuation of the engine based on the pulse signal output from the pulse signal generating means. Further, as in claim 3, the rotation fluctuation detection means may be configured to detect the rotation fluctuation of the engine based on a difference or a ratio of front and rear pulse intervals.

[0009]

[0010] Alternatively, as claimed in claim 4, the battery voltage detecting means for detecting a battery voltage provided, the determination reference value varying means, the battery voltage determination reference value for determining whether the pulse interval is changed It may be changed in multiple steps or continuously according to the detection result of the detection means.

Further, as in claim 5 , engine cooling water temperature detecting means for detecting the cooling water temperature of the engine is provided, and the discrimination reference value varying means sets the discrimination reference value for discriminating whether or not the pulse interval has changed. It may be changed in multiple steps or continuously according to the detection result of the engine cooling water temperature detecting means.

According to a sixth aspect of the present invention, an intake air amount variation detecting means for detecting an intake air amount variation of the engine is provided,
The determination reference value varying means may change the determination reference value for determining whether or not the pulse interval has changed in multiple steps or continuously according to the detection result of the intake air amount variation detection means.

Alternatively, as described in claim 7 , two or more pieces of information are detected from the engine rotation fluctuation, the rotation speed, the battery voltage, the engine cooling water temperature, and the intake air quantity fluctuation, and the detected two or more pieces of information are detected. The final determination reference value may be determined by combining the determination reference values obtained based on each piece of information.

[0014]

By the way, while the engine speed is constant, the pulse signal generating means outputs pulse signals at equal intervals except for a predetermined crank angle (position of the toothless portion or the surplus tooth portion) This region is referred to as "equal-interval pulse region"), and pulse signals having different pulse intervals at a predetermined crank angle are output. This circumstance does not change even when the engine is rotating at a low speed, but if the engine speed changes, the pulse interval also changes in the even-interval pulse region. Therefore, even when the engine speed is low, if the rotational speed does not change, the pulse interval in the equidistant pulse region and the pulse interval at the predetermined crank angle can be accurately determined without changing the determination reference value. . However, when the engine speed fluctuates, the pulse interval also fluctuates even in the even-interval pulse region. Therefore, when the fluctuation of the pulse interval due to the fluctuation of the engine rotation becomes large, this fluctuation of the pulse interval becomes It becomes confusing with the change, and it becomes difficult to accurately distinguish the two.

From such a relationship, the present inventor has determined that the main cause of erroneously recognizing a change in the pulse interval is not the level of the engine rotation speed but the rotation fluctuation, and the inventions of the above-mentioned claims are considered. It was done.

That is, according to the structure of claim 1, the rotation fluctuation detecting means detects the rotation fluctuation of the engine, and the discrimination reference value varying means changes the discrimination reference value in accordance with the detection result. In this way, the crank angle determining means accurately determines the change in the pulse interval based on the determination reference value that changes according to the rotation fluctuation of the engine, and determines the crank angle based on that.

In this case, according to the second aspect, the rotation fluctuation detecting means detects the rotation fluctuation of the engine based on the pulse signal output from the pulse signal generating means. That is, the magnitude of the fluctuation of the engine rotation is detected by the magnitude of the fluctuation of the pulse interval in the equidistant pulse region.

Further, in claim 3, the rotation fluctuation detecting means detects the rotation fluctuation of the engine based on the difference or ratio of the front and rear pulse intervals. This utilizes the fact that the difference or ratio between the front and rear pulse intervals in the equally-spaced pulse region becomes data that reflects the magnitude of engine rotation fluctuation in real time.

[0019]

By the way, since the battery voltage changes according to the engine speed, the battery voltage can be used as information that reflects the engine speed. Therefore, as in claim 4, to detect the battery voltage, if the multi-stage or continuously changing the determination reference value according to the detection result, changes the discrimination criterion value in accordance with the rotational fluctuation of the engine It is possible to discriminate between a change in pulse interval due to a change in engine rotation and a change in pulse interval at a predetermined crank angle.

Further, as the engine cooling water temperature becomes lower,
Since the engine friction increases and the engine rotation becomes unstable, the engine rotation fluctuation tends to increase as the engine cooling water temperature decreases. Therefore, in claim 5 , the engine cooling water temperature is detected, and the determination reference value is changed in multiple steps or continuously according to the detection result.

Further, it can be estimated whether the operating state of the engine is in the transient state or not based on the fluctuation of the intake air amount of the engine. Therefore, in the sixth aspect , the variation of the intake air amount of the engine is detected, and the determination reference value is changed in multiple steps or continuously according to the detection result.

Further, in claim 7 , two or more pieces of information are detected from among the fluctuations in the engine rotation, the number of rotations, the battery voltage, the engine cooling water temperature, and the fluctuations in the intake air amount, and each of the two or more detected information is detected. The final determination reference value is determined by combining the determination reference values obtained based on the above. Thereby, the discrimination accuracy can be further improved.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS. First, a schematic configuration of the entire engine control system will be described with reference to FIG. In this embodiment, for example, a 6-cylinder engine (not shown) is controlled, and accordingly, 6 ignition coils 11-16 and 6 fuel injection valves 21-26 are provided corresponding to the 6 cylinders. I have it. In this 6-cylinder engine, a cylinder, a cylinder, and a cylinder form a cylinder group in which respective pistons move in the same phase. For example, when one cylinder of the cylinder group is in an explosive stroke, the other cylinder intakes. In the process.

The output pulse signal (NE signal) of the crankshaft sensor 31 and the output pulse signal (G signal) of the camshaft sensor 32, which will be described later, are output to the electronic control unit 33 (hereinafter referred to as "ECU").
33 ”). The ECU 33 calculates cylinder discrimination, reference position, rotation speed and the like based on the NE signal and the G signal, and each switch 34 to 36 such as a starter switch and an idle switch, and an air flow meter 38 for detecting the intake air amount. The optimum ignition timing and fuel injection amount are calculated based on the operating state information output from the battery 39 and the water temperature sensor 40 that detects the engine cooling water temperature, and the NE signal and the G signal, and the ignition signal is sent to the igniter 37. It outputs and controls the on / off of the ignition coils 11 to 16 of each cylinder, and outputs a fuel injection signal to control the fuel injection operation of each fuel injection valve 21 to 26.

As shown in FIG. 4, the crankshaft sensor 31 faces the outer circumference of the crank-side detection disk 42 fitted to the crankshaft 41, and is equidistantly arranged on the outer circumference at a pitch of, for example, 10 ° CA. It is an electromagnetic pickup sensor that detects the formed teeth 43. In this embodiment, toothless portions 44, 45, 46 having two missing teeth are formed at three locations on the outer circumference of the crank side detection disk 42, and the toothless portion 44 is formed.
The position of is opposite to the crankshaft sensor 31 when the crankshaft 41 rotates to the crank angle corresponding to the cylinder or the compression top dead center of the cylinder (hereinafter referred to as “TDC1” and “TDC6”, the same applies to other cylinders). It is located at a position separated by 4 and 5 teeth in the rotation direction (arrow direction) of the crankshaft 41 from the tooth 43a. Further, the toothless portions 45 and 46 are TD
It is located at a position separated by 1, 2 and 4 teeth in the rotation direction of the crankshaft 41 from the teeth 43b facing the crankshaft sensor 31 at C2 and TDC5. Incidentally, TDC
3, teeth 4 facing the crankshaft sensor 31 at TDC 4
A toothless portion is not formed in the vicinity of 3c.

The crankshaft sensor 31 functions as a "pulse signal generating means", and depending on the rotation of the crankshaft 41, as shown in FIG.
Except for positions (to positions 46 to 46), pulse signals (NE signals) at equal intervals are output, and the pulse interval becomes about three times longer at a predetermined crank angle (positions of the toothless portions 44 to 46).

On the other hand, the cam shaft sensor 32, as shown in FIG. 5, is opposed to the outer circumference of the cam side detection disk 48 fitted to the cam shaft 47, and is formed at two predetermined positions on the outer circumference thereof. This is an electromagnetic pickup type sensor that detects the teeth 49a and 49b. In this embodiment, the positions of the teeth 49a and 49b are 30 ° away from the position when the cam shaft 47 rotates to the crank angle corresponding to TDC2 and TDC6 in the rotation direction (arrow direction) of the cam shaft 47. Located in. Incidentally, T
No teeth are formed in the vicinity of the position facing the camshaft sensor 32 at DC1, TDC3, TDC4, and TDC5.

The pulse signal (G signal) output from the camshaft sensor 32 is used to invert the G latch from nothing (0) to having (1) as shown in FIG. Here, as shown in FIG. 7A, when the G signal is input, the G latch is continuously output from immediately after the NE signal input to the 7th signal input. It is a rectangular pulse. While this G latch is being output, TDC
2, by setting so that TDC6 comes, it is possible to discriminate between TDC2 and TDC5 by the presence or absence of the G latch, and
6 and TDC1 can be discriminated.

By executing the control program shown in FIG. 1, the above-mentioned ECU 33 functions as "rotational fluctuation detecting means" for detecting the rotational fluctuation of the engine by the difference between the pulse intervals before and after the NE signal, and at the same time, the NE signal. Discrimination value K for discriminating whether or not the pulse interval of is changed
It functions as "discrimination reference value varying means" that changes a and Kb in accordance with the engine speed fluctuation, and further discriminates the change in the pulse interval of the NE signal based on these discrimination reference values Ka and Kb. It functions as "crank angle determination means" for determining the crank angle with reference. Below, this E
The control content of the CU 33 will be described in detail with reference to the flowchart of FIG.

The flowchart of FIG. 1 is executed every time an NE signal is input from the crankshaft sensor 31, and determines the specific positions of the cylinders corresponding to the toothless portions 44 to 46.

When the processing of this flowchart is started,
First, the counter n is incremented by "1" (step 101), the pulse interval T of the NE signal is detected, and the pulse interval T is stored as Tn (step 102).
Then, the difference ΔT = Tn-2 between the pulse intervals Tn-2 and Tn-3 obtained by the processing of the previous-previous time (n-2) and the processing of the previous-previous time (n-3).
-Tn-3 is calculated (step 103), and the discrimination reference values Ka and Kb are obtained as follows based on the difference ΔT (step 104). In advance, as shown in FIG. 2, ΔT and K
The RO of the ECU 33 is set as a map of the correspondence relationship between a and Kb.
It is stored in M and Ka and Kb corresponding to ΔT obtained in step 102 are obtained from the map. Or ΔT and Ka
, Kb is converted into a mathematical expression and the ROM of the ECU 33 is stored.
Stored in the formula, and the Δ calculated in step 102
It is also possible to substitute T to calculate Ka and Kb.
Here, Ka is a discrimination reference value for detecting the first toothless portion 44 or 45, and Kb is the second toothless portion 4
6 is a discrimination reference value for detecting 6.

After the discrimination reference values Ka and Kb are obtained in this way, the routine proceeds to step 105, where the pulse interval Tn-1 obtained in the previous processing (n-1) and the processing two times before (n-2). Compare the obtained pulse interval Tn-2 with the value multiplied by Ka,
It is determined whether Tn-1> Ka Tn-2. If the pulse interval does not change, it is Tn-
If 1 ≤ Ka Tn-2, the judgment in step 104 is "N.
Then, the processing ends.

On the other hand, if Tn-1> Ka Tn-2, that is, if the determination in step 105 is "Yes", it means that the pulse is not in the equidistant pulse region, so that TDC of either cylinder or
In step 106, it is determined whether or not In this step 106, the pulse interval T obtained in this processing is
n is compared with a value obtained by multiplying the pulse interval Tn-1 obtained in the previous (n-1) process by Kb to determine whether Tn> Kb Tn-1. If TDC2,5 of cylinder, Tn> Kb Tn-1, but BTDC of cylinder
At 20 ° CA (see FIG. 4), Tn ≦ Kb Tn-1.

In this step 106, Tn> Kb Tn-1
If it is judged that the cylinder is the TDC 2 or 5 of the cylinder, the routine proceeds to step 107, where it is judged whether or not the G latch is present. If there is a G latch, it is determined to be cylinder TDC2 (step 109), and if there is no G latch, it is determined to be cylinder TDC5 (step 11).
0).

On the other hand, in step 106, Tn ≤ Kb Tn-
If it is determined to be 1, the process proceeds to step 108 to determine whether BTDC of the cylinder is 20 ° CA, and it is determined whether or not the G latch is present. If there is a G latch, it is determined that the cylinder has BTDC of 20 ° CA (step 1
11), BTDC of cylinder is 20 ° C without G latch
It is judged to be A (step 112).

According to the first embodiment described above, the pulse signal (NE signal) output from the crankshaft sensor 31.
The discrimination reference values Ka and Kb are changed according to the difference (Tn-2 -Tn-3) between the pulse intervals before and after, but the reason is that the difference between the pulse intervals before and after (Tn-2 -Tn- Since 3) is the information that reflects the engine speed fluctuation, the discrimination reference value Ka depends on the difference (Tn-2 −Tn-3) between the front and rear pulse intervals.
, Kb are changed to change the discrimination reference values Ka, Kb according to the fluctuation of the engine rotation. In this way, the determination reference value Ka is determined according to the engine rotation fluctuation.
, Kb, the change in the pulse interval of the NE signal can be accurately discriminated, and the crank angle determination precision can be improved.

Moreover, if the pulse signal (NE signal) output from the crankshaft sensor 31 is used as a means for detecting the engine rotation fluctuation, a dedicated sensor for detecting the engine rotation fluctuation is not provided. Also, the cost increase can be suppressed.

However, when the NE signal is used as a means for detecting the engine speed fluctuation, it is not limited to the difference between the front and rear pulse intervals (Tn-2 -Tn-3). For example, the ratio of the front and rear pulse intervals ( Tn-2 / Tn-3) is also information reflecting the engine speed fluctuation, and therefore the ratio of front and rear pulse intervals (Tn-2 / Tn-3) as in the second embodiment of the present invention shown in FIG. May be calculated, and the discrimination reference values Ka and Kb may be changed according to the calculation result. Also in this case, Tn-2 / T
ECU3 as a map of the correspondence between n-3 and Ka, Kb
It is stored in the ROM of No. 3 and Ka and Kb corresponding to the calculated Tn-2 / Tn-3 are obtained from the map. Or Tn-2 /
The correspondence relationship between Tn-3 and Ka, Kb is converted into a mathematical expression and the ECU 3
Tn-2 stored in ROM 3 and calculated according to the formula
It is also possible to substitute / Tn-3 to calculate Ka and Kb.

By the way, since the toothless portions 44 to 46 are provided at positions where the rotational speed decreases, even if the discrimination reference values Ka and Kb are increased at the time of low rotation, the toothless portions 44 to 46 are provided.
Is easy to detect, and the regions other than the toothless portions 44 to 46 (equal-interval pulse regions) are less likely to be mistaken for the toothless portions. However, when the rotation speed is high, if the determination reference values Ka and Kb are large, it becomes difficult to determine the toothless portions 44 to 46. Therefore, in the third embodiment of the present invention shown in FIG. 9, the determination reference values Ka and Kb are continuously increased as the rotation speed decreases in the low rotation speed range, while the middle rotation speed range and the high rotation speed are changed. In the area, the discrimination reference values Ka and Kb are kept constant at relatively small values.

In the third embodiment, the crankshaft sensor 3
1 according to the pulse interval of the NE signal output from the ECU
33 (rotation speed detection means) detects the rotation speed of the engine,
The discrimination reference values Ka and Kb are continuously changed in accordance with the engine speed in a low rotation range where the rotation fluctuation is large. In this way, the discrimination reference values Ka and K are determined according to the engine speed.
If b is continuously changed, when the engine speed fluctuates, the determination reference value also changes accordingly, and as a result, the engine speed is changed in the same manner as in the first and second embodiments described above. It is possible to discriminate between the variation of the pulse interval due to the variation and the variation of the pulse interval at a predetermined crank angle.

By the way, since the battery voltage changes according to the engine speed, the battery voltage can be used as information reflecting the engine speed. From this viewpoint, in the fourth embodiment of the present invention shown in FIG.
(Battery voltage detecting means) detects the voltage of the battery 39, and in the region where the engine speed decreases and the battery voltage decreases, the determination reference values Ka and Kb are continuously increased as the battery voltage decreases. Change to. Thus, even if the discrimination reference values Ka and Kb are continuously changed according to the battery voltage, the discrimination reference values Ka and Kb are substantially continuously changed according to the engine speed.

Further, as the engine cooling water temperature becomes lower,
Since the engine friction increases and the engine rotation becomes unstable, the engine rotation fluctuation tends to increase as the engine cooling water temperature decreases. From this point of view, in the fifth embodiment of the present invention shown in FIG. 11, the engine cooling water temperature is detected by the water temperature sensor 40 (engine cooling water temperature detecting means), and the engine cooling water temperature lowers and the rotation of the engine becomes unstable. In the region, the determination reference values Ka and Kb are continuously increased as the engine cooling water temperature decreases.

Further, it can be estimated whether the operating state of the engine is in the transient state or not based on the fluctuation of the intake air amount of the engine. Therefore, in the sixth embodiment of the present invention shown in FIG. 12, the ECU 33 (intake air amount variation detecting means) detects the intake air amount variation based on the output signal of the air flow meter 38, and determines the discrimination criterion according to the detection result. The values Ka and Kb are continuously changed.

In each of the first to sixth embodiments described above, the discrimination reference values Ka and Kb are continuously changed, but they are changed in multiple steps (three or more steps). It goes without saying that it is also good.

Furthermore, in order to improve the discrimination accuracy, two or more pieces of information are detected from the above-mentioned fluctuations in engine rotation, rotation speed, battery voltage, engine cooling water temperature, and fluctuations in intake air amount, and the two detected information are detected. The final determination reference value may be determined by combining the determination reference values obtained based on each of the above information. An embodiment embodying this is a seventh embodiment of the present invention shown in FIG.

In the seventh embodiment, first, step 20
1, the determination reference values KaB and KbB based on the battery voltage are obtained from the relationship of FIG. Next, at step 202, the discrimination reference value KaN according to the engine speed from the relationship of FIG.
Find KbN. Thereafter, in step 202, final discrimination reference values Ka and Kb are calculated from the following equation. Ka = α ₁ KaB + β ₁ KaN Kb = α ₂ KbB + β ₂ KbN where α ₁ and β ₁ are weighting factors of Ka, and α ₂ and β ₂ are K.
It is a weighting factor of b.

If the final discrimination reference values Ka and Kb are determined from a plurality of information as in the seventh embodiment, the discrimination accuracy can be further improved.

In the above-described embodiment, in order to change the pulse interval of the pulse signal (NE signal) output from the crankshaft sensor 31 at a predetermined crank angle, the tooth missing on the outer circumference of the crank side detection disk 42. Although the portions 44 to 46 are formed, an extra tooth may be formed in that portion to narrow the pulse interval.

[0050]

As is apparent from the above description, according to the structure of claim 1 of the present invention, the engine rotation fluctuation is detected, and the discrimination reference value is changed according to the detection result. In comparison with the conventional system in which the judgment reference value is switched in two steps between the low rotation range (or at the time of starting) and the high rotation range, the change in the pulse interval can be accurately judged, and the crank angle It is possible to improve the determination accuracy of.

Further, according to the second aspect, since the engine rotation fluctuation is detected based on the pulse signal output from the pulse signal generating means, it is not necessary to provide a dedicated sensor for detecting the engine rotation fluctuation. Also, the cost increase can be suppressed.

Further, according to the third aspect, since the engine speed fluctuation is detected based on the difference or ratio of the front and rear pulse intervals, the engine speed fluctuation can be detected in real time with high accuracy.

[0053]

[0054] In claim 4, detects the battery voltage can be used as information reflecting the speed of the engine, since the discrimination reference value according to the detection result so as to change the multi-stage or continuously, also changes determination reference value in accordance with the rotational fluctuation of the engine, it is possible to distinguish between changes in the pulse interval of the crank angle variation with a predetermined pulse interval due to the rotation fluctuation of the engine.

[0055] In claim 5, detects a significant impact engine coolant temperature to the friction of the engine,
Since the discrimination reference value is changed in multiple steps or continuously according to the detection result, it is possible to set the discrimination reference value in consideration of the friction of the engine.

[0056] In claim 6, the operating state of the engine detects an intake air amount variation of the engine as the information can be estimated whether it is a transient state, multi-stage determination reference value according to the detection result Alternatively, since it is changed continuously, it is possible to set the determination reference value in consideration of the transient state of the engine.

Further, in claim 7 , two or more pieces of information are detected from among the fluctuations in the engine rotation, the number of revolutions, the battery voltage, the engine cooling water temperature, and the fluctuations in the intake air amount, and each of the detected two or more pieces of information. Since the determination reference values determined based on the above are combined to determine the final determination reference value, the determination accuracy can be further improved.

[Brief description of drawings]

FIG. 1 is a flowchart of a control program showing a first embodiment of the present invention.

FIG. 2 is a diagram showing a relationship between a difference (Tn-2 −Tn-3) between front and rear pulse intervals and discrimination reference values Ka and Kb.

FIG. 3 is a block diagram showing an electrical configuration.

FIG. 4 is a diagram showing a relationship between a crankshaft sensor and a crank-side detection disc.

FIG. 5 is a diagram showing a relationship between a cam shaft sensor and a cam side detection disc.

FIG. 6 is a diagram showing a waveform of a pulse signal (NE signal) output from a crankshaft sensor.

FIG. 7 is a signal waveform diagram of each part for explaining the role of a G signal output from the camshaft sensor.

FIG. 8 is a diagram showing a relationship between a difference Tn-2 / Tn-3 between front and rear pulse intervals and discrimination reference values Ka and Kb in the second embodiment of the present invention.

FIG. 9 is a diagram showing a relationship between an engine speed and discrimination reference values Ka and Kb in the third embodiment of the present invention.

FIG. 10 is a diagram showing the relationship between the battery voltage and the judgment reference values Ka and Kb in the fourth embodiment of the present invention.

FIG. 11 is a diagram showing a relationship between engine cooling water temperature and discrimination reference values Ka and Kb in the fifth embodiment of the present invention.

FIG. 12 is a diagram showing the relationship between the change over time of the intake air amount and the change over time of the discrimination reference values Ka and Kb in the sixth embodiment of the present invention.

FIG. 13 is a flowchart of a control program showing a seventh embodiment of the present invention.

[Explanation of symbols]

31 ... Crankshaft sensor (pulse signal generating means), 32
... cam shaft sensor, 33 ... ECU (crank angle determination means,
Rotational fluctuation detecting means, discrimination reference value varying means, rotational speed detecting means, battery voltage detecting means, intake air amount variation detecting means), 40 ... Water temperature sensor (engine cooling water temperature detecting means), 41 ... Crank shaft, 42 ... Crank side Disc, 44
... 46 ... missing tooth portion, 47 ... cam shaft, 48 ... cam side detection disc.

Continuation of the front page (56) Reference JP-A-61-250017 (JP, A) JP-A-1-277662 (JP, A) JP-A-5-71909 (JP, A) JP-A-4-219448 (JP , A) (58) Fields surveyed (Int.Cl. ⁷ , DB name) G01D 5/00-5/62 G01P 1/00-3/80 F02D 45/00

Claims (7)

(57) [Claims] 1. A pulse signal generating means for generating pulse signals at equal intervals according to the rotation of a crankshaft of an engine and changing the pulse intervals at a predetermined crank angle; A crank angle determination device for an engine, comprising: a crank angle determination means for determining a crank angle based on a reference; a rotation variation detection means for detecting a rotation variation of the engine; and a determination as to whether or not the pulse interval has changed. A crank angle determination device for an engine, comprising: a determination reference value varying unit that changes a determination reference value according to a detection result of the rotation variation detection unit. 2. The rotation fluctuation detecting means is configured to detect a rotation fluctuation of the engine based on a pulse signal output from the pulse signal generating means. Engine crank angle determination device. 3. The rotation variation detecting means is configured to detect the rotation variation of the engine based on a difference or a ratio of front and rear pulse intervals.
Crank angle determination device for the engine described. 4. A pulse signal generating means for generating pulse signals at equal intervals according to rotation of a crankshaft of an engine and changing the pulse intervals at a predetermined crank angle; A crank angle determining device for an engine, comprising a crank angle determining means for determining a crank angle as a reference, a battery voltage detecting means for detecting a battery voltage, and a determination reference value for determining whether or not the pulse interval has changed. A crank angle determining device for an engine, comprising: a determination reference value varying means for varying the value in multiple stages or continuously according to the detection result of the battery voltage detecting means. 5. A pulse signal generating means for generating pulse signals at equal intervals according to the rotation of a crankshaft of an engine, and the pulse intervals changing at a predetermined crank angle; A crank angle determining device for an engine, comprising: a crank angle determining means for determining a crank angle based on a reference; an engine cooling water temperature detecting means for detecting a cooling water temperature of the engine; and determining whether or not the pulse interval has changed. Crank angle determining device for an engine, comprising: a determination reference value varying unit that changes the determination reference value according to the detection result of the engine cooling water temperature detecting unit in multiple stages or continuously. 6. A pulse signal generating means for generating pulse signals at equal intervals according to the rotation of a crankshaft of an engine, and the pulse intervals changing at a predetermined crank angle; A crank angle determination device for an engine, comprising: a crank angle determination means for determining a crank angle based on a reference; an intake air amount variation detection means for detecting an intake air amount variation of the engine; and whether or not the pulse interval has changed. A crank angle determining device for an engine, comprising: a determination reference value varying means for varying a determination reference value for determining whether the intake air amount variation detection means is changed in multiple stages or continuously. 7. A pulse signal generating means for generating pulse signals at equal intervals according to the rotation of a crankshaft of an engine and changing the pulse intervals at a predetermined crank angle; A crank angle determining device for an engine, comprising: a crank angle determining means for determining a crank angle based on a reference, wherein two or more of the engine rotational fluctuation, rotational speed, battery voltage, engine cooling water temperature, and intake air amount fluctuation are selected. And a discrimination reference value for discriminating whether or not the pulse interval has changed are finally determined by combining the discrimination reference values obtained based on each of the two or more pieces of information. A crank angle determining device for an engine, comprising: a determination reference value varying means.