JPS60259968A - Abnormality detection for engine rotation sensor and measurement for revolution of engine when abnormal - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (Technical Field) The present invention detects an abnormality in an engine rotation sensor that outputs a signal that determines a characteristic quantity of an internal combustion engine, that is, a failure in the sensor itself or its wiring system, and detects the engine rotation speed at the time of the abnormality. Regarding measurement methods.

(Technical background of the invention and its problems) Fuel supply control in which the amount of fuel supplied to the engine is controlled by electrically controlling the valve opening time of a fuel metering device that supplies fuel to the internal combustion engine. The method uses a reference value for the amount of fuel, which is determined according to the engine speed and the absolute pressure in the intake pipe, and the specifications that represent the operating state of the engine, such as engine cooling water temperature, throttle valve opening, and exhaust concentration (oxygen concentration). ) etc., the reference value is corrected by adding and/or multiplying a constant and/or coefficient according to The present applicant has proposed a fuel supply control method in which the timing is determined and the injection valve is driven in accordance with the corrected fuel amount.

Detection of the engine speed is essential in such a control method, and if an abnormality occurs in the engine speed sensor system and the detected value of the engine speed fluctuates even though the engine is operating normally, It becomes impossible to accurately control the fuel supply to the engine as described above, and as a result, the engine cannot be operated smoothly, and in some cases, there is a risk that the engine may stop.

(Object of the Invention) The present invention has been made in view of the above-mentioned points, and it detects an abnormality in the engine rotation sensor, and in the event of an abnormality, measures the engine rotation speed using a cylinder discrimination sensor instead of the engine rotation sensor. purpose.

(Summary of the Invention) In order to achieve this object, in the present invention, intervals between crank angle position signals sequentially output from an engine rotation sensor disposed in an internal combustion engine at a predetermined crank angle position of the engine are sequentially measured. However, when the engine rotation sensor changes at once from a value outside one area sandwiching the area defined by the previous and current divided values or the first and second predetermined values to a value outside the other area. An abnormality detection method for an engine rotation sensor that determines that an engine rotation sensor is abnormal, and a cylinder that sequentially outputs an output from a cylinder discrimination sensor that is disposed in the engine and detects a predetermined crank angle position of a specific cylinder of the engine when an abnormality occurs. The present invention provides a method for measuring engine rotation speed when an engine rotation sensor is abnormal, in which the rotation speed of the engine is measured by measuring the interval time of the discrimination signal.

(Example of the invention) An embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a block diagram of a discrimination circuit of an electronic control unit of a fuel supply control device to which the control method of the present invention is applied, in which an engine rotation sensor 1 and a cylinder discrimination sensor 2 are respectively arranged around the crankshaft of an engine (not shown). and
The engine rotation sensor 1 detects a TDC signal, that is, at a predetermined crank angle position every 180° rotation of the engine crankshaft, and the cylinder discrimination sensor 2 detects a predetermined crank angle position of a specific cylinder, as shown in FIG. 2(a). pulse signal Pa
, Pa' are output as one pulse. These pulse signals Pa and Pa' are each processed by a waveform shaping circuit 3°4 as shown in Fig. 2(b).
After being shaped into rectangular wave pulse signals pb, pb' as shown in FIG.

On the other hand, constant voltage times &! 811 is ignition switch 1
When 0 is on, it is connected to the battery 9 and a predetermined voltage V c
Output c. The trigger pulse generation circuit 12 includes a resistor R,
and capacitor C! It consists of a series circuit with a diode D1 connected in parallel with a resistor R3, and a Schmitt trigger circuit 13 which receives the output of a capacitor CI as an input, and a voltage Vcc is applied from a constant voltage circuit 1. That is, when the ignition switch 10 is turned on, a trigger pulse Pt is output and applied to the input terminal of the down counter 32 and the reset input terminal R of the flip-flop circuit 34.

When the trigger pulse pt is applied, the preset down counter 32 takes in ET DCF5 data corresponding to a fixed number of times, for example, 10 times, and presets it. The flip-flop circuit 34 is connected to an output terminal Q to which a trigger pulse Pt is applied.
The output of the output terminal becomes a low level (hereinafter referred to as 0), the output of this output terminal becomes a high level (hereinafter referred to as 1), and the output terminal Q or the output 1 of Q is added to the input side of the AND circuit 5, 16 or 6, 17. Make it open.

The pulse signal pb output from the waveform shaping circuit 3 is applied to the sequence pulse generation circuit 8 via an AND circuit 5 and an OR circuit 7. The sequence pulse generation circuit 8 sequentially outputs pulse signals CPo-C20 as shown in FIG. 2(c) to (f) at a predetermined timing every time the pulse signal pb is input, and each of these pulse signals CPo, ＋cp
I, CF2 and C20 are set to Me value register 20. M
It is added to the e value counter 19, the previous Me value register 21, and the AND circuit 31.

The Me value counter 19 receives a pulse signal cp1 (Fig. 2(d)
)) is reset each time the AND circuit 16,
Clock pulses CP input to input terminal CK through OR circuit 18 are counted.

That is, the Me value counter 19 is the engine rotation sensor 1.
The number of clock pulses CP inputted between the TDC signals (FIG. 2(a)) sequentially outputted from is counted. Therefore, the content Me of this Me value counter ]9 corresponds to the time between TDC signals, and is the reciprocal of the engine rotation speed Ne (1/N
Corresponds to e).

The Me value register 20 receives the pulse signal CPo (Fig. 2 (C
)) is input, the content Me of the Me value counter 19 is taken in, and this value Me is added to each input terminal A, , A2 of the Me value register 2J and the comparators 23, 24. M
The e value register 21 receives the pulse signal CP3 (FIG. 2(f))
M output from the Me value register 20 each time is inputted.
Import the e value. The contents of the Me value register 20 are the current M.
The contents of register 21 represent the previous value of Me.

The contents of the Me value register 21 are applied to the input terminals AO, A3 of the comparator 22.25. A predetermined value M is stored in the memory 26.
e F S l is stored, and this predetermined value M e
F S + is applied to the input terminal BO+82 of comparator 22.24. The memory 27 stores a predetermined value Mar! : A predetermined value Meps2 (>MerSl) larger than I is stored, and this predetermined value M e F S 2 is stored in the comparator 23.2.
5 is applied to the input terminal B I r B 3.

The comparator 22 inputs the previous Me value from the Me value register 21.
value and the predetermined value M e F S l input from the memory 26
When Me<Me F S +, the output is 1.
becomes. The comparator 23 compares the current Me value input from the Me value register 20 with the predetermined value M e p input from the memory 27.
S 2 is compared, and the output becomes 1 when Me)Me F S 2. The outputs of these comparators 22 and 23 are applied to an AND circuit 28. The output of the AND circuit 28 becomes 1 when the outputs of the comparators 22 and 23 are both 1.

The comparator 24 receives the current Me input from the Me value register 20.
The value is compared with a predetermined value MersH input from the memory 26, and the output becomes 1 when Me<MerSl. The comparator 25 compares the previous Me value input from the Me value register 21 and a predetermined value M a F S 2 input from the memory 27, and outputs 1 when Me)MeFs2. The outputs of these comparators 24 and 25 are applied to an AND circuit 29. The output of the AND circuit 29 becomes 1 when the outputs of the comparators 24 and 25 are both 1. AND circuit 28 or 29
Each output 1 of
This pulse signal CP2 is generated every time the pulse signal CP2 is opened as shown in FIG.
It is sequentially applied to the input terminal CK of the down counter 32 as a pulse signal synchronized with , and the contents of this down counter 32 are sequentially subtracted.

Then, when the content of the down counter 32 becomes O, the output of the output terminal 100 of the down counter 32 becomes 0,
The flip-flop circuit 34 is set and the output terminal Q,
The outputs of Q become 1 and 0, respectively, AND circuits 5 and 16 are closed, and ant circuits 6 and 17 are opened.

Then, the pulse signal Pb' outputted from the waveform shaping circuit 4 instead of the pulse signal Pb is sent to the AND circuit 6 and the OR circuit 7.
The sequence pulse generating circuit 8 is connected to the sequence pulse generating circuit 8 as shown in FIG. 2(c) in the same manner as described above.
The pulse signals CPo-C20 shown in ~(f) are sequentially output. The pulse signal (cylinder discrimination signal) Pa' output from the cylinder discrimination sensor 2 is (1/number of cylinders) times the pulse signal (TDC signal) Pa output from the engine rotation sensor 1. For example, in the case of a 4-cylinder engine. is the pulse Pa'
The number is 1/4 of Pa. That is, the period of pulse Pa' is four times that of pulse Pa.

Therefore, the frequency dividing circuit 15 divides the clock pulse CP into 1/4 according to the output pulse Pa' of the cylinder discrimination sensor 2, outputs the clock pulse CP', and outputs the clock pulse CP'.
It is added to the Me value counter 19 via the OR circuit 18. M
The e-value counter 19 receives the clock pulse CP input from the time when the pulse CPI is applied and reset until the next pulse CP is applied and reset, as described above.
Count the number of ′. Me value register 20 is pulse C
Every time Po is added, the content Me of the Me value counter 19 is taken in. The content of the Me value counter 19 corresponds to the time between pulses Pa' successively output from the cylinder discrimination sensor 2, and corresponds to the reciprocal number 1/N'e of the engine rotational speed Ne. Therefore, the content of the Me value register 20 is a value representing the engine rotation speed Ne, and the engine rotation speed can be assigned.

M e [The content Me of the register 20 corresponds to the engine rotation speed Ne measured by the engine rotation sensor 1 when the engine rotation sensor 1 is normal, and corresponds to the cylinder discrimination when the engine rotation sensor 1 is abnormal. This corresponds to the engine rotation speed Ne measured by the output signal of the sensor, that is, the cylinder discrimination signal.

The data in this Me value register 20 is stored in a fuel injection amount calculation circuit of an electronic control unit (not shown).

Added to injection timing control circuit, etc.

FIG. 3 is a flowchart showing the method of the present invention described above, in which it is determined whether the ignition switch IO is on or not, that is, whether the engine is in an operating state and rotating (step 1), and the answer is negative (No). At this time, abnormality detection of the engine rotation sensor 1 or measurement of the engine rotation speed by the cylinder discrimination sensor 2 is not performed, and if the answer is affirmative (Yes), the Me value is calculated (step 2). The Me value is a value indicating the time between each crank angle signal (TDC signal) sequentially output from the engine rotation sensor 1, and corresponds to the reciprocal of the engine rotation speed Ne (1/N e ), and the engine rotation speed When Ne is high, the value is small, and when Ne is low, the value is large. Next, it is determined whether the calculated previous Me value is larger than the first predetermined value M e F S 2 (step 3), and if the answer is affirmative (Yes), the current Me value is set to the second predetermined value. The value MeFSI (<MeFs
In step 4), if the answer is affirmative (Yes), it is determined that the engine rotation sensor 1 is abnormal. That is, the previous Me value is thicker than the first predetermined value MeFs2 (Me>Me F S
2), the current Me value is the second predetermined value M e F s
When it is smaller than 1 (Me (Mersl<MeFs2)), the fluctuation in the engine speed Ne is larger than the fluctuation that normally occurs, and in such a case, it is determined that the engine speed sensor 1 is abnormal.In this case, as shown in FIG. The output of the AND circuit 29 becomes 1.

If the determination in step 3 or 4 is negative (No), that is, the previous Me value is the first predetermined value M e F S
2 (Me<Me F S 2 ), or when the current Me value is larger than the second predetermined value M e F S I (Me, > Me F S + ), the previous Me value is It is determined whether or not it is smaller than the second predetermined value M e F S + (step 5), and the answer is positive (Y
es), the current Me value is the first predetermined value M e F
Step 6) to determine whether it is larger than S2.
If the answer is affirmative (Yes), it is determined that the engine rotation sensor 1 is abnormal. That is, the previous Me value is smaller than the second predetermined value M G F S l (Me<M e
F S l < MoF S 2 ), the current Me value is larger than the first predetermined value M e F S 2 (M
e>MeFsz), the variation in the engine rotation speed Ne is larger than the variation that would normally occur, as described above, and in such a case also, it is determined that the engine rotation sensor 1 is abnormal. At this time, the output of the AND circuit 28 in FIG.
becomes.

If the determination in step 5 or 6 is negative (No), that is, the previous Me value is the second predetermined value M e p s
greater than 1 (Me>Me F S + ).

Alternatively, the current Me value is the first predetermined value M e F S 2
When it is smaller than (Me<Me F S 2 ), it is determined that the engine rotational speed sensor 1 is normal, since the fluctuation in the engine rotational speed Ne is small and within a normally possible range.

If the determination results in steps 3 and 4 or steps 5 and 6 are affirmative (Yes), the ignition switch 10
The number of deviations from turn on to turn off is integrated (
Step 7) Determine whether or not the predetermined number of times ETDCFS has been reached.Step 8) If the answer is negative (No), determine that engine rotation sensor 1 is normal, and confirm (Yes)
In this case, it is determined that the engine rotation sensor 1 is abnormal, and the engine rotation speed Ne is measured using the cylinder discrimination sensor 2 instead of the engine rotation sensor 1 (step 9).

Once it is determined that there is an abnormality, this state continues. Here, the cumulative number ETDC is set to 0 when the ignition switch is turned on.

In this embodiment, the previous Me value of the interval time of the crank angle signal is thicker than the first predetermined value, and the current M
When the e value is smaller than a second predetermined value that is smaller than the first predetermined value, or the current Me value is larger than the first predetermined value and the previous Me value is smaller than the first predetermined value. A case has been described in which two discrimination means are provided to determine that the engine rotation sensor is abnormal when the engine rotation sensor is smaller than a predetermined value. Of course it's a good thing.

In addition, although the integration period has been described as the period from when the ignition switch 10 is turned on to when it is turned off, this period may also be a fixed period, and in this case, the ETo
If crs has not been reached, 4.Reset the value to O and add up the number of times it has failed.

(Effects of the Invention) As explained above, according to the present invention, the interval between crank angle position signals sequentially output from an engine rotation sensor provided in an internal combustion engine at a predetermined crank angle position of the engine is sequentially measured. , when the previous and current measured values change at once from a value outside one area sandwiching the area defined by the first and second predetermined values to a value outside the other area, the engine rotation sensor is abnormal. This makes it possible to quickly and easily detect abnormalities such as disconnections in the engine rotation sensor system, and also to reduce the interval between cylinder discrimination signals output from the cylinder discrimination sensor when an abnormality occurs in the engine rotation sensor system. Since the time is sequentially measured and the engine rotational speed is measured based on the measured value, fuel supply to the engine can be controlled, and the engine can be operated smoothly and continuously.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of a discrimination circuit of an electronic control unit of a fuel supply control device to which the method for detecting an abnormality in an engine rotation sensor and the method for measuring the engine rotation speed at the time of abnormality according to the present invention are applied. FIG. 2 is a timing chart of each signal in the discrimination circuit of FIG. 1, and FIG. 3 is a diagram showing an embodiment of a flowchart for carrying out the method of the present invention. Engine rotation sensor, 2... Cylinder discrimination sensor, 3, 4
... Waveform shaping circuit, 8... Sequence pulse generation circuit, 15... Frequency division circuit, 19. Me value counter, 20.2
]...Me value register, 22~・25...Comparator,
26, 27. 33・Memory, 32・Down counter, 34...Flip-flop circuit. Applicant Honda Motor Co., Ltd. Agent Patent Attorney Toshihiko Watanabe Agent Patent Attorney Kouji Nagato

Claims (1)

[Claims] 1. The interval between crank angle position signals sequentially output from an engine rotation sensor disposed in an internal combustion engine at a predetermined crank angle position of the engine is sequentially measured, and the previous and current measurement values are The engine rotation sensor is determined to be abnormal when a value outside one area sandwiching the area defined by the first and second predetermined values changes at once to a value outside the other area. An abnormality detection method for an engine rotation sensor, characterized by: 2. The abnormality determination is performed when the previous measured value is larger than the first predetermined value and the current measured value is smaller than the second predetermined value, which is smaller than the first predetermined value. A method for detecting an abnormality in an engine rotation sensor according to item 1. 3. The abnormality determination is performed when the current count value is larger than the first predetermined value and the previous measured value is smaller than the second predetermined value, which is smaller than the first predetermined value. A method for detecting an abnormality in an engine rotation sensor according to item 1. 4. Sequentially measure the interval between crank angle position signals that are sequentially output from an engine rotation sensor disposed in the internal combustion engine at a predetermined crank angle position of the engine, and the previous and current measurement values are the first and second ones. The engine rotation sensor is determined to be abnormal when it changes all at once from a value outside one area sandwiching the area defined by the predetermined values to a value outside the other area, and when an abnormality occurs, the sensor installed in the engine is The rotational speed of the engine is measured by measuring the interval time between cylinder discrimination signals sequentially output from a cylinder discrimination sensor that detects a predetermined crank angle position of a specific cylinder of the engine. A method for measuring engine rotation speed when an engine rotation sensor is abnormal. 5. The abnormality determination is performed when the previous measured value is larger than the first predetermined value and smaller than the current measured value or a second predetermined value that is smaller than the first predetermined value. A method for measuring engine rotation speed when the engine rotation sensor is abnormal according to item 4. 6. The abnormality determination is performed when the current measurement value is larger than the first predetermined value and the previous measurement value is smaller than the second predetermined value, which is smaller than the first predetermined value. A method for measuring engine rotation speed when the engine rotation sensor is abnormal according to item 4.