JPH0692770B2 - Engine controller - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention detects flow rate information of intake air passing through an intake passage of an engine based on a frequency at which a Karman vortex is generated, and based on the intake flow rate information of the engine, The present invention relates to an engine control device that controls an operating state.

(Prior Art) An engine control device detects the flow rate of intake air passing through an intake passage of the engine by a Karman vortex airflow meter based on the frequency of a Karman vortex and detects the operation control amount of the engine from the detected signal. (Fuel supply amount, ignition timing, etc.) is calculated, and this operation control amount is corrected by the engine temperature, exhaust gas amount, etc., and the engine operating state is controlled based on the correction result (fuel supply amount, ignition timing, etc.) There is something to do.

The Karman vortex type air flow meter is provided in the intake passage of the engine, and as shown in FIG. 15, a rectifier 1, a passage 2 of sound absorbing material, a vortex generating column 3, a vortex stabilizing flat plate 4, an ultrasonic transmitter 5,
It is composed of the ultrasonic receiver 6 and an electronic circuit. The intake air is rectified by the rectifier 1 and passes through the passage 2 made of the sound absorbing material, and the vortex generation column 3 generates a row of Karman vortices. The generation frequency of this Karman vortex is proportional to the flow velocity of the intake air, and the ultrasonic wave of about 40 KHZ transmitted from the ultrasonic transmitter 5 to the ultrasonic receiver 6 is affected by the Doppler effect due to the rotating flow of the Karman vortex The propagation time from the transmitter 5 to the ultrasonic receiver 6 changes. That is, this propagation time changes according to the change of the Karman vortex generation frequency due to the change of the flow velocity of the intake air, and the ultrasonic wave from the ultrasonic transmitter 5 is phase-modulated by the flow velocity of the intake air (therefore, the flow rate of the intake air) to receive the ultrasonic wave. It will be received at 6. In the electronic circuit, as shown in FIG. 16, the oscillator circuit 7 transmits a pulse signal to the ultrasonic transmitter 5 to transmit an ultrasonic wave, and at the same time, the same pulse signal as that pulse signal is phase-compared via the average phase tracking circuit 8. The signal is output to the circuit 9 as a reference signal, and the output signal of the ultrasonic receiver 6 is phase-demodulated by the phase comparison circuit through the amplifier 12 and the phase demodulation circuit, and output. Further, since the propagation time slowly changes depending on the temperature of the intake air, the low-frequency component (frequency component lower than the Karman vortex generation frequency) due to the change of the intake air temperature is detected from the output signal of the phase comparison circuit 9 by the low-pass filter 11. The average phase tracking circuit 8 shifts the phase of the pulse signal from the ultrasonic receiver 6 in response to the detection signal, and corrects the modulation due to the intake air temperature.

The engine control device includes a synchronous system for controlling the operating state of the engine in synchronization with the output signal of the Karman vortex air flow meter, and other systems.

(Problems to be Solved by the Invention) In the above conventional engine control device, as shown in FIG. 17, the intake pulsation (pressure fluctuation) is generated in the low speed fully open region where the engine is low speed and the throttle valve is in the fully open region. Becomes large, the output signal frequency of the Karman vortex air flow meter decreases, and a large control amount error occurs. That is, in the Karman vortex airflow meter, the ultrasonic transmitter 5 to the ultrasonic receiver 6
The time that the ultrasonic wave propagates to changes not only by the intake flow rate and intake temperature but also by the intake pulsation, and the ultrasonic wave
The phase is modulated by the intake air temperature and intake pulsation. The output signal of the ultrasonic receiver 6 is subjected to phase demodulation and correction of the modulation due to the intake air temperature by an electronic circuit. Further, the intake air temperature modulates the ultrasonic wave more slowly than the Karman vortex, but the intake pulsation also modulates the ultrasonic wave relatively slowly. Therefore, the low-pass filter 11 detects not only the modulation amount due to the intake air temperature but also the intake pulsation and causes the average phase tracking circuit 8 to shift the phase of the reference signal. Then, in the low-speed fully open range, the flow velocity of the intake air changes greatly due to the intake pulsation, and the phase deviation amount of the reference signal approaches the limit value, so the ultrasonic wave is overmodulated by the Karman vortex, so the Karman vortex air The output signal frequency of the flowmeter is reduced by that amount, which causes a large control amount error. In particular, in the synchronous method, the control error is large because not only the control amount but also the control timing causes an error due to a decrease in the output signal frequency of the Karman vortex air flow meter.

Although there is a technique to correct the output signal of the Karman vortex flowmeter by the pressure signal in the downstream of the throttle valve or in the air cleaner, these technologies do not use the pressure signal in the vicinity of the Karman vortex flowmeter. Fluctuations due to pulsation could not be removed accurately in real time.

(Means for Solving Problems) The present invention relates to a throttle valve installed in an engine intake passage, a vortex generator installed upstream of the throttle valve in the intake passage, the throttle valve, and the throttle valve. Corresponding to the number of Karman vortices generated from the ultrasonic transmitter and the ultrasonic receiver, which are arranged to face each other across the intake passage between the vortex generators, from the signals received by the ultrasonic receiver. Pickup means for extracting the signal component of the frequency, pressure detection means for detecting the pressure in the intake passage near the ultrasonic transmitter and ultrasonic receiver placement positions, and the pickup means for extracting the signal component based on the signal from the pressure detection means. Correction means for removing fluctuations due to inspiration pulsation from the generated signal component, waveform shaping means for converting the output from the correction means into a pulse signal, and the same waveform The present invention is characterized by comprising control means for generating an engine control output signal in response to a pulse signal from the shaping means, and an engine operating state adjusting element for operating in response to the engine control output signal.

(Operation) The pick-up means extracts the signal component of the frequency corresponding to the number of generated Karman vortices from the signal received by the ultrasonic receiver, and the pressure detecting means detects the vicinity of the ultrasonic transmitter and ultrasonic receiver arrangement positions. Detect the pressure in the intake passage. The correction means removes the fluctuation component due to the intake pulsation from the signal component extracted by the pickup means based on the signal from the pressure detection means, and the waveform shaping means converts the output from the correction means into a pulse signal. Then, the control means receives the pulse signal from the waveform shaping means to generate an output signal for engine control, and the engine operating state adjusting element operates by receiving the output signal for engine control.

(Embodiment) FIG. 1 shows an embodiment of the present invention.

This embodiment is a multi-point injection type fuel control system for an engine, in which an air cleaner 23 is integrated with an air cleaner 23 in an air intake port 22 of an intake passage 22 for introducing intake air into each fuel chamber of an engine 21 composed of a four-cylinder internal combustion engine. An air flow meter 24 is attached. Karman vortex air flow meter
An intake pressure sensor 26 for detecting the intake pressure state in the intake passage 22 is attached to the intake passage 24, and an intake air temperature sensor 27 for detecting the intake air temperature in the intake passage 22 near the downstream side of the Karman vortex air flow meter 24. Is provided. The Karman vortex type air flow meter 24 has the same structure as that shown in FIGS. 15 and 16, and as shown in FIG. 2, the correction means is constituted via the output signal Vp amplifier 50 of the intake pressure sensor 26. The subtraction circuit 51 is subtracted from the output signal Vcfo of the phase comparison circuit 9 serving as a pickup means, and the output signal of the subtraction circuit 51 is shaped into a rectangular wave by the waveform shaping circuit 20. That is, the output signal Vcfo of the phase comparison circuit 9 has a true waveform vi corresponding to the intake flow velocity (flow rate) and a strain amount based on the intake pulsation (a strain amount based on the intake pressure).
Since k ₁ · Vp is heavy, the output signal Vp of the intake pressure sensor 26 is AC-amplified (gain k ₁ times) by the amplifier 50 in order to remove distortion from this signal Vcfo, and then the phase comparison circuit 9 The subtraction circuit 51 performs the subtraction operation on the output signal Vcfo.
Therefore, the output signal of the phase comparison circuit 9 is corrected by the subtraction circuit 51 based on the intake pressure state in the intake passage, and even if intake pulsation occurs in the low speed wide open range, the variation due to the intake pulsation is subtracted. Waveform shaping circuit removed at 51
The output signal of 20 becomes a pulse signal (Karman vortex signal) having a frequency proportional to the intake air amount per unit time.

As shown in FIG. 1, a throttle valve 28 interlocked with an accelerator pedal is provided downstream of the Karman vortex airflow meter 24 in the intake passage 22, and the downstream end of the intake passage 22 is connected via an intake manifold 29. It communicates with the intake port of each cylinder head of the 4-cylinder engine 21. An exhaust passage 31 communicating with the exhaust port of each cylinder head of the engine 21 via an exhaust manifold 30 is provided with an O ₂ sensor 32 for detecting the oxygen concentration in the exhaust gas, and the cooling water temperature of the engine 21 is also provided. A water temperature sensor 33 for detecting, a crank angle sensor, and a cylinder discrimination sensor are provided, and output signals of these sensors are input to the controller 25. The crank angle sensor and the cylinder discrimination sensor are provided in the distributor 34, and the second
As shown in the figure, the crank angle sensor 35 includes protrusions 36 to 39 provided on the outer circumference of the rotor shaft 34a of the distributor 34 at equal intervals by the same number as the number of cylinders, and the protrusions 36 to 39 at fixed positions.
It is composed of a pickup 40 for detecting 39, and one rotation of the distributor 34 (two rotations of the crankshaft) causes the pickup 40 to output as many crank phase signals (engine rotation speed information) as there are cylinders. Cylinder discrimination sensor
Reference numeral 41 denotes a protrusion 42 provided on the rotor shaft 34a of the distributor 34, and pickups 43 to 45, 19 arranged at equal intervals around the rotor shaft 42a and detecting the protrusion 42.
Distributor 34 from this pickup 43-45,19
One rotation (two crankshaft rotations) sequentially outputs the same number of output signals as the number of cylinders. Electromagnetic fuel injection valves 46 to 49 are arranged in the respective branch passage portions of the intake manifold 29 in proximity to the respective intake ports. One end of each of the electromagnetic fuel injection valves 46 to 49 communicates with each branch passage of the intake manifold 29,
The other end communicates with an open end of a fuel passage communicating with a fuel tank via a pump and a fuel pressure regulator. At the other end of the fuel passage from the position where the injection valves 46 to 49 are arranged, a constant pressure (low pressure) is constantly maintained by the action of the pump and the fuel pressure regulator.
The fuel in the fuel passage is supplied to each of the branch passages of the intake malafold 29 when the valve bodies of the electromagnetic fuel injection valves 46 to 49 are opened based on the injector drive signal from the controller 25. It is designed to be injected into the department. The amount of fuel injected into each branch passage depends on the valve opening time of the electromagnetic fuel injection valves 46 to 49.

As shown in FIG. 2, the controller 25 is a central processing unit (CP
U) 52, read only memory (ROM) 53, random access memory (RAM) 54 and microcomputer having ports 55 to 57, 80, cylinder discrimination external register 59, 16-bit free running counter 60, registers 61 to 64 , Comparators 65 to 68, RS flip-flops 69 to 72, and the like. The output signal of the waveform shaping circuit 20 is input to the interrupt terminal INT2 of the CPU 52, the crank phase signal from the pickup 40 is shaped into a rectangular wave by the waveform shaping circuit 73, and the CPU 5
Input to 2 interrupt pin INT1. Also pickup 43
The cylinder discrimination signals from ~ 45 and 19 are shaped into rectangular waves by the waveform shaping circuits 74 to 77 and input to the register 59. The intake air temperature sensor 27, the O ₂ sensor 32, the water temperature sensor 33, and the throttle sensor 78.
The signals from the same are adjusted to appropriate levels by the level adjusting circuits 79 to 82, analog / digital converted by the analog / digital converters 83 to 86, and input to the ports 55 to 57 and 80. Further, a signal is input to the microcomputer from a start switch, an idle sensor, etc., and the electromagnetic fuel injection valves 46 to 49 are solenoid valves for opening and closing the valve body 46.
Power supply from DC power supply 87 to a to 49a is transistors 88 to 91.
It is controlled to be turned on and off, and opened and closed.

By the way, since the basic fuel supply amount required per unit time is proportional to the amount of air taken into the engine (engine) per unit time, when operating the electromagnetic fuel injection valve for each crank phase signal, Is to set the data that gives the basic valve opening time (driving pulse width) per electromagnetic fuel injection valve according to the amount of air taken in between two adjacent crank phase signals. Therefore, in the present embodiment, the information about the intake air amount between the adjacent crank phase signals is obtained based on the number of Karman vortex signals generated between the adjacent crank phase signals, and the basic information described above is obtained based on this information. Various valve opening time data is set.

The above-mentioned basic valve opening time data setting, subsequent actual valve opening time data setting, and correction data based on each operating state of the engine used when setting this actual valve opening time data The setting is performed by calculation in the CPU 52, and the operation performed by the CPU 52 using the RAM 54 according to the program in the ROM 53 will be described below.

The one shown in Fig. 3 has the Karman vortex signal interrupt terminal INT2.
Is a Karman vortex interrupt routine that performs an interrupt process every time it is input to the CPU 52. When the Karman vortex signal is input from the waveform shaping circuit 20 to the interrupt terminal INT2, the CPU 52 first starts at step A1.
Add 1 to the data held in the address FK of RAM54, then read the current value of the free running counter 60 in step A2, and read this value and the free running counter that was read at the previous program execution and input to the address TA of RAM54. The difference from the value of 60 is obtained, and the data of this difference is input to the address TK of the RAM 54. Next, at step A3, the value of the free-running counter 60 read during the execution of the program this time is input to the address TA, and the interrupt process is ended. Since this interrupt processing is executed every time the Karman vortex signal K is generated, the Karman vortex signal K is integrated in step A1. Also step
In A2, the time interval between the most recently generated Karman vortex signal and the most recent Karman vortex signal preceding this Karman vortex signal is obtained as the difference in the value of the free running counter 60.

If the crank phase signal is input during the execution of the Karman vortex interrupt routine, the interrupt processing by the crank phase signal (crank phase interrupt routine) described later has priority over this Karman vortex interrupt routine. At this point, the execution of the Karman vortex interrupt routine is once interrupted, and the Karman vortex interrupt routine is executed after the interrupt processing by the crank phase signal is completed.

In the case shown in Fig. 4, the crank phase signal is the interrupt terminal.
This is a crank phase interrupt routine that performs an interrupt process each time it is input to INT1, and when the crank phase signal is input to the interrupt terminal INT1 from the waveform shaping circuit 73, the CPU 52 first executes step B1.
In, read the value of the free running counter 60,
Store in address TC of RAM54. Next, at step B2, the value of the free running counter 60 at the time of generating the crank phase signal read at step B1 and the crank phase signal already read at step A3 of the Karman vortex interrupt routine and stored at the address TA are preceded. Free running counter 60 for the most recent Karman vortex signal generation
The difference ΔT with the value of
It is stored in a predetermined address of RAM 54. Then step B
In step 3, the difference data ΔT obtained in step B2 is divided by the data obtained in step A2 of the Karman vortex interrupt routine and stored in address TK, and the quotient data that is the result of this division is further divided. Compare with 1 which is the upper limit. Step
As a result of the comparison in B3, when the quotient data is 1 or less, the process proceeds to step B4. In step B4, the above quotient data is added to the data of the pulse generation number of the Karman vortex signal obtained in step A1 of the Karman vortex interrupt routine and stored in the address FK, and further stored in the address FRAC of the RAM54. The data is subtracted and the result of this operation is stored in address D of RAM 54. By the way, as is clear from the explanation of Step B5 and Step B7 described later,
The FRAC stores the above quotient data (hereinafter referred to as the previous quotient data) obtained in the previous crank phase interruption routine, or if the previous quotient data exceeds the upper limit value 1, The upper limit value 1 is stored. And step B4
In step B5 following, the quotient data obtained in step B3 of the current crank phase interrupt routine is added to the address FR
Store in AC. The quotient data stored in the address FRAC in step B5 is used in the calculation in step B4 of the next crank phase interruption routine and step B6 described later. Then, after step B5, step B8
Leading to. On the other hand, if it is determined in step B3 that the quotient data is larger than the upper limit value 1, step B6
Then, in step B6, the upper limit value of 1 is added to the data of the number of Karman vortex signal occurrences stored in the address FK, the data stored in the address FRAC is further subtracted, and the result of this operation is added to the address D To store. At this time, the data of the address FRAC is the same as in the case of step B4 described above. Then, in step B7 following step B6, the upper limit value 1 is stored in the address FRAC. This step
The data of the upper limit value stored in the address FRAC in B7 is
It will be used in the next calculation in steps B4 and B6 of the crank phase interrupt routine. And step
After B7, the process goes to step B8.

At step B8, the content of the address FK is reset to 0, and then at step B9 the data d stored at the address D is compared with the clip value of the address AC which will be described later. If the data d is not larger than the clip value, the process proceeds to step B10 to convert the data d into time data ts that gives the valve opening time (driving pulse width) of the electromagnetic fuel injection valve.
Store in address TS of RAM54. The data d and the time data ts basically have a relationship of ts = a × d (where a is a positive constant), and the value of this a is stored in the ROM 53. Then, in step B11, the data in address TS is multiplied by the data in address K, and the product is stored again in address TS. The data data of the address K is data for correcting the valve opening time of the electromagnetic fuel injection valve 14 according to the engine operating state, and is calculated in the main routine described later. Also, step B9
If the data d is larger than the clip value, the process proceeds to step B12 and the clip value is stored in the address TS to clip the data d. Then step
At B13, the value of the free running counter 60 is read again and stored in the address TC. Next, in step B14, the data at address TS is added to the data at address TC and the sum is added.
TO is calculated, and it is determined in step B15 whether the content R of the cylinder discrimination external register 59 is 0 or not. here,
In the four-cylinder engine 21, the fuel is repeatedly injected in the order of the first cylinder, the third cylinder, the fourth cylinder, and the second cylinder by the electromagnetic fuel injection valves 46 to 49 which are the engine operating state adjusting elements. However, the cylinder to which the fuel is injected is detected by the cylinder discrimination sensor 41 and input to the cylinder discrimination external register 59. When the content R of the register 59 is 0 (first cylinder signal), that is, when the fuel should be injected into the first cylinder by the electromagnetic fuel injection valve 46, the process proceeds to step B16 and the sum TO is registered in the register 61. And outputs a set signal to the flip-flop 69 in step B17. Therefore, the flip-flop 69 is activated by this set signal and the solenoid
Fuel is injected into the second cylinder by the operation of 47a and opening of the electromagnetic fuel injection valve 47. After that, when the value of the free-running counter 60 reaches the value of the register 62 and an output signal is output from the comparator 66, the flip-flop 70 is reset by this output signal, the transistor 89 is turned off, the solenoid 47a is turned off, and the electromagnetic wave is turned off. Type fuel injection valve 47 is closed.

If the content R of the register 59 is not 1 in the judgment of step B18, the CPU 52 proceeds to step B21. If the content of the register 59 is 2 in the judgment in step B21, the operation proceeds to step B22 and the above T
O is set in the register 63, and a set signal is output to the flip-flop 71 in step B23. The flip-flop 71 is set by the set signal, the transistor 90 is turned on by the output signal, and the solenoid 48a is operated to open the electromagnetic fuel injection valve 48, so that fuel is injected into the third cylinder. After that, when the value of the free-running counter 60 reaches the value of the register 63 and an output signal is output from the comparator 67, the flip-flop 71 is reset by this output signal, the transistor 90 is turned off, and the solenoid 48a is turned off and the electromagnetic wave is turned off. Type fuel injection valve 48 closes. CPU52 is step B21
If the content R of the register 59 is not 2 in the above judgment, the process proceeds to step B24 to set the TO in the register 64, and the set signal is output to the flip-flop 72 in step B25.
The flip-flop 72 is set by this set signal, the transistor 91 is turned on by the output signal, and the solenoid 49a is actuated to open the electromagnetic fuel injection valve 49, so that fuel is injected into the fourth cylinder. After that, the value of the free running counter 60 reaches the value of the register 64 and the comparator
When an output signal is output from 68, the flip-flop 72 is reset by this output signal and the transistor 91 is turned off.
The solenoid 49a is turned off and the electromagnetic fuel injection valve 49 is closed.

The cylinder discrimination sensor 41 is the rotor shaft 34 of the distributor 34.
The 1st cylinder signal, the 3rd cylinder signal, the 4th cylinder signal, and the 2nd cylinder signal are sequentially repeated and output according to the rotation of a, so the electromagnetic fuel injection valves 46 to 49 are in the order of 46, 48, 49, 47. When opened, fuel is injected in the order of the first cylinder, the third cylinder, the fourth cylinder, and the second cylinder.

The CPU 52 proceeds from step B17, B20, B23, B25 to step B26, and compares the time data between the adjacent crank phase signals from the waveform shaping circuit 73 with the time data of the free running counter 60 (crank phase signal input time data). If necessary, a plurality of time data immediately before the latest time data is stored and stored, and by averaging the immediately previous time data and the latest time data, the engine speed data (engine speed The cycle data, which is the reciprocal of the above, is calculated and stored in the address of the RAM 54, and the interrupt processing is ended. Since the above cycle data is data for every 180 ° of crank, the reciprocal thereof is twice the engine speed.

By the way, since the data of the address FK is set to 0 every time in step B8 of the crank phase interrupt routine, the Karman vortex signal integration performed in step A1 of the Karman vortex interrupt routine is started from 0 every time the crank phase signal is generated. Will be done. Therefore, the value of the data of the address FK input to the address D in step B4 or step B6 in the crank phase interrupt routine at the time of generating an arbitrary crank phase signal is the latest crank that precedes the arbitrary crank phase signal. This corresponds to the number of pulses of the Karman vortex signal generated between the generation of the phase signal and the generation of the arbitrary crank phase signal.

In this crank phase interrupt routine, the value of the free running counter 60 at the time of generating the crank phase signal read in step B1 is used to determine the Karman vortex interrupt when the latest Karman vortex signal preceding the crank phase signal is generated. Read address TA in step A2
The value of the free-running counter 60 input to is subtracted and the difference is calculated in step B2.The difference is calculated by the crank phase signal that forms the trigger signal and the most preceding crank phase signal. It corresponds to measuring the time interval between the Karman vortex signal forming the latest pulse signal.

Furthermore, in step B3 of this crank phase interrupt routine, for any crank phase signal C (n),
Arbitrary crank phase signal C obtained in the immediately preceding step B2
(N) and the most recent Karman vortex signal K (i) preceding this crank phase signal C (n), the time interval ΔT (n)
And the Karman vortex signal K (i) obtained in the Karman vortex interrupt routine at the time of generation of the Karman vortex signal K (i) and input to the address TK.
The most recent Karman vortex signal K (i- that precedes (i)
The division with the time interval TK (i) with 1) is performed, but this is nothing but the conversion of the former time interval data ΔT (n) into the pulse number of the Karman vortex signal. That is, the data ΔT (n) is the Karman vortex signal K
Time until the crank phase signal C (n) is generated in the time interval TK (i + 1) between (i) and the first Karman vortex signal K (i + 1) following this Karman vortex signal K (i) It represents interval data, and Karman vortex signal K (i)
Assuming that the intake air amount from the generation time point to the Karman vortex signal K (i + 1) generation time is constant, the time interval data TK (i + 1) corresponds to one part of the data of the number of Karman vortices. Therefore, the data obtained by dividing ΔT (n) by TK (i + 1) is the Karman vortex signal K
The time interval data between (i) and the crank phase signal C (n) is converted into the number of Karman vortices, and further data
The data ΔT (n) can be divided by the data TK (i) by assuming that TK (i) and the data TK (i + 1) are equal to each other. Equivalent to converting to. By the way, time interval data Δ
In converting T (n) into the number of Karman vortex signals, it is considered that the data TK (i) and the data TK (i + 1) are equal, and the data ΔT (n) is the data TK (i +).
Since 1) is never exceeded, if the quotient data obtained by dividing the data ΔT (n) by the data TK (i) exceeds 1,
The reliability of the quotient data becomes extremely thin.

That is, there should be no Karman vortex signal between the Karman vortex signal K (i) and the crank phase signal C (n) in reality, but the quotient data exceeds 1.
The result shows that the Karman vortex signal exists between the two signals K (i) and C (n). Therefore, in step B3,
It is determined whether or not the quotient data exceeds 1, and when the quotient data does not exceed 1, the quotient data is added as it is in step B4, and when the quotient data exceeds 1. The quotient data is converted into an upper limit value of 1, and this upper limit value of 1 is added in step B6.

Then, step B4 and step in the crank phase interrupt routine at the time of generating an arbitrary crank phase signal C (n)
At B6, the data of the pulse number of the Karman vortex signal generated between the crank phase signal C (n) and the most recent crank phase signal C (n-1) preceding this crank phase signal C (n) is obtained. On the other hand, data obtained by converting the time interval between the crank phase signal C (n) and the most recent crank phase signal C (n-1) preceding this crank phase signal C (n) into the pulse number of the Karman vortex signal ( The upper limit value 1) is added, and the time interval between the crank phase signal C (n-1) and the most recent Karman vortex signal preceding this crank phase signal C (n-1) is converted into the number of Karman vortex signals. Data (upper limit value 1) is subtracted and the crank phase signal C (n
The data regarding the intake air amount information between -1) and the crank phase signal C (n) is obtained, and the obtained data is input to the address D. The data of the address D is corrected by the data of the address K or, if it is larger than the clip value in the address AC, clipped by the clip value and converted into the opening time (driving pulse width) data of the electromagnetic fuel injection valve. Will be done.

FIG. 5 shows a main routine that is repeatedly executed in the CPU 52 when the interrupt processing by the interrupt signal such as the Karman vortex signal and the crank phase signal is not performed. In step C1, the information of each sensor 27, 32, 33, 78, etc. stored in the RAM 54 is read, and in step C2, the A / F (inhalation during warm-up and high load during acceleration) is read based on the information. RAM amount by calculating the A / F correction coefficient for A / F control such as A / F leaning during air-fuel / fuel-rich), deceleration, and partial load
Store at address K of 4. This A / F correction coefficient is used in step B11 of the crank phase interruption routine. next,
In step C3, the basic clip value C ₀ is read from the RAM 53 according to the engine speed data obtained in step B26 of the crank phase interruption routine and stored in the RAM 54. This basic clip value C ₀ is a value that clips the drive time of the electromagnetic fuel injection valve that is determined based on the intake air amount / engine speed, and intakes for four cylinders in one engine operation cycle (two crank rotations). To more surely correct the Karman vortex air flow meter erroneous measurement (other than the above correction) when determining the drive time of the electromagnetic fuel injection valve based on the measured value of the air amount (the number of Karman vortex signals) It is a value. In the Karman vortex air flow meter, as shown in FIG. 9, there is a phenomenon that the signal frequency jumps up due to intake blowback (intake backflow) in the low speed fully open range, and the clip suppresses the jump up. In the ROM 53, the relationship between the basic clip value and the engine speed as shown in FIG. 6 is mapped and stored, and the basic clip value C ₀ corresponding to the engine speed data is stored.
Read out. Here, when the temperature of the intake air is low, the volumetric efficiency is low (the intake air expands in the combustion chamber of the engine), and when the temperature of the engine is low, the volumetric efficiency decreases less (the expansion of the intake air in the combustion chamber). Therefore, the basic clip value C ₀ needs to be corrected by the intake air temperature and the engine temperature. Therefore, in step C4, the clip coefficient Kfat corresponding to the temperature of the intake air is read from the ROM 53 by the detection signal of the intake air temperature sensor 27, and in step C5, the clip coefficient Kfwt corresponding to the cooling water temperature is read from the ROM 53 by the detection signal of the water temperature sensor 33. read out. This clip coefficient Kfat,
Kfwt is a coefficient for correcting the basic clip value C _{0 according} to the temperature of the intake air and the temperature of the cooling water, and the ROM 53 shows the relationship between the clip coefficient Kfat and the temperature of the intake air as shown in FIG. 7 and FIG. The relationship between the clip coefficient Kfwt and the cooling water temperature as shown in is stored as a map. Then step
At C6, the basic clip value C ₀ is corrected by the clip coefficients Kfat and Kfwt to obtain a clip value, the clip value is stored in the address AC of the RAM 54, and the process returns to step C1. This address
The AC clip value is the step of the crank phase interrupt routine.
Used in B9 and B12.

FIG. 10 shows another embodiment of the present invention.

This embodiment is a single-point injection type fuel control device, and in the above-mentioned embodiment, the electromagnetic fuel injection valves 92, 93 which are the engine operating state adjusting elements are provided in the intake passage 22.
Is provided between the Karman vortex type air flow meter 24 and the throttle valve 28. The electromagnetic fuel injection valves 92, 93 have one end communicating with the intake passage 22 and the other end communicating with the open end of the fuel passage communicating with the fuel tank via the pump and the fuel pressure regulator, depending on the valve opening time. Inject a quantity of fuel. Then, as shown in FIG. 11, transistors 94, 95 for turning on / off the valve body opening / closing solenoids 92a, 93a of the electromagnetic fuel injection valves 92, 93, flip-flops 96, 97, comparators 98, 99,
Two registers 100 and 101 are provided, and the cylinder discrimination sensor 4
1 and the cylinder discrimination external register 59 are omitted.

Further, a controller 25a is used instead of the controller 25, and this controller 25a is the controller 2
In FIG. 5, CPU52a, ROM102 is used instead of CPU52, ROM53. The ROM 102 is obtained by partially modifying the contents of the ROM 53 as follows. The CPU 52a executes steps C1 to C7 in the main routine as shown in FIG.
After proceeding to step C2, the basic pulse width D ₀ is read from the ROM 102 and set, and then the procedure advances to step C2. This basic pulse width D ₀ is the drive pulse width of the electromagnetic fuel injection valves 92, 93 which give the theoretical air-fuel mixture 14, 7. In step C3, the basic clip value C ₁ is read from the ROM 102 according to the engine speed data obtained in the crank phase interruption routine and stored in the RAM 54.

The ROM 102 stores, as a map, the relationship between the basic clip value (value that clips the Karman vortex signal frequency) C ₁ and the engine speed as shown in FIG. 14, and the basic clip value C ₁ In steps C4 to C6, the relationship between the clip coefficients Kfat and Kfwt for correcting the intake air temperature and the cooling water temperature and the intake temperature and the cooling water temperature is mapped and stored. Although not shown in the CPU 52a in the crank phase interrupt routine, the output signal of the waveform shaping circuit 73 is the interrupt terminal.
When it is input to INT1 and interrupted, the interval of the interrupt is measured by the free-running counter 60, and the measured value is stored in a predetermined address of RAM54 as engine speed data and used in step C3 of the main routine. To do.

Further, in the Karman vortex interrupt routine, the CPUa receives a Karman vortex signal from the waveform shaping circuit 20 to the interrupt terminal INT2 as shown in FIG. 13, and first, in step A11, the intake air amount data RΔTK and the address AC of the RAM 54 are input. It is determined whether it is smaller than 1 by multiplying it with the clip value stored in. The intake air amount data RΔTK is obtained by calculating the period of the Karman vortex signal as described later, and it is necessary to determine whether or not the multiplication value of the period data RΔTK and the clip value is smaller than 1 as the measured value of the intake air amount. Whether or not (Karman vortex signal frequency) becomes equal to or greater than the clip value is determined, that is, whether or not the predetermined correction area in which the malfunction due to the intake blowback of the Karman vortex air flow meter 24 must be suppressed is entered. Will be detected. If RΔTK × clip value ≧ 1 and the correction area is not entered, the process proceeds to step A12, and the basic pulse width D ₀ set in step C7 of the main routine is set in RAM54.
The driving time data Df of the electromagnetic fuel injection valve is calculated by correcting with the A / F correction coefficient stored in the address K of
When ΔTK × clip value <1, the process proceeds to step A13, and the basic pulse width D ₀ is multiplied by RΔTK × AC to obtain drive time data Df of the electromagnetic fuel injection valve. That is, in the correction region, the basic pulse width D ₀ is R ΔTK × AC instead of the A / F correction coefficient.
Is corrected and the driving time data Df of the electromagnetic fuel injection valve is clipped (fixed). Next, in step A14, the value of the free running counter 60 is read and the address T of the RAM 54 is read.
After storing in R, the above time data is stored in that value in step A15.
Df is added, and the result is added to registers 100 and 101 in step A16.
Set to. Next, in step A17, the flag KN is checked, and if it is 0, the process proceeds to step A18, a set signal is output to the flip-flop 96, and the flag KN is set in step A19. If the flag KN is 1, the process proceeds to step A20. The set signal is output to the flip-flop 97, and the flag KN is reset in step A21. That is, in steps A17 to A21, the set signal is alternately output to the flip-flops 96 and 97 once (every time when the Karman vortex interrupt routine is executed). When the flip-flop 96 is set by the set signal, the transistor 94 is turned on by the output signal of the flip-flop 96, the solenoid 92a is operated, and the electromagnetic fuel injection valve 92 is opened. After that, when the value of the free-running counter 60 reaches the value of the register 100 and the output signal of the comparator 98 is output, the flip-flop 96 is reset by this output signal, the transistor 94 is turned off, and the solenoid 92a is turned off to turn on the electromagnetic signal. Type fuel injection valve 92 is closed. Further, when the flip-flop 97 is reset by the set signal, the transistor 95 is turned on by the output signal of the flip-flop 97, the solenoid 93a is activated, and the electromagnetic fuel injection valve 9
3 open. After that, the value of flip-flop 96 is set to register 1
When the value of 01 is reached and the output signal of the comparator 99 is output, the flip-flop 97 is reset by this output signal, the transistor 95 is turned off, the solenoid 93a is turned off, and the electromagnetic fuel injection valve 93 is closed.

Further, the CPU 52a proceeds from step A19, A21 to step A22 to calculate the difference ΔTK between the data of the addresses TR, MTK of the RAM 54. The data of addresses TR and MTK are the same as the previous step A1
It is a value read from the free-running counter 60 in step 4, and the difference ΔTK is data indicating the interval between the Karman vortex signal that has entered this time at the interrupt terminal INT2 and the Karman vortex signal before that. Next, in step A23, the data ΔTK obtained this time in step A22, the previous time, the time before last, and the addresses M0ΔTK, M1ΔTK, M2Δ of the RAM 54 obtained in step A22 before that respectively.
The data stored in TK is doubled by the current data ΔTK, the weight is weighted and added with other data, and the result is divided by 5 to calculate the average value RΔTK, which is stored in the RAM 54. It will be used in step A11 next time. Next, at step A24, the current data of the address TR is moved to the address MTR and used as the previous data next time. Next, in steps A25 and A26, whether the counter J is 0 or not,
Check whether it is 1. If the counter J is 0 in step A25, the data ΔTK obtained in step A22 this time is put in the address M0ΔTK in step A27, the counter J is incremented in step A28, and the counter J is not 0 in step A25 and the counter J is counted in step A26. If J is 1, the data ΔTK is put in the address M1ΔTK in step A29, and the counter J is incremented in step A28. If the counter J is neither 0 nor 1 in steps A25 and A26, then in step A30. The data ΔTK is put in the address M2ΔTK and the counter J is reset in step A31. That is, the data .DELTA.TK is sequentially entered into the addresses M0.DELTA.TK, M1.DELTA.TK, M2.DELTA.TK once (every time when the Karman vortex interrupt routine is executed), and the interrupt processing is finished in steps A28 and A31.

The present invention can be similarly applied to a device for controlling the ignition timing of the engine, and even if the Karman vortex air flow meter is different from the above-mentioned one, in the case of malfunction due to the pressure condition in the intake passage, It can be implemented similarly.

As described above, according to the present invention, the throttle valve installed in the intake passage of the engine, the vortex generator installed upstream of the throttle valve in the intake passage, and the throttle valve. And the ultrasonic transmitter and the ultrasonic receiver arranged so as to face each other across the intake passage between the vortex generator and the vortex generator, from the signal received by the ultrasonic receiver to the number of Karman vortices generated Pickup means for extracting a signal component of a corresponding frequency, pressure detection means for detecting the pressure in the intake passage near the ultrasonic transmitter and ultrasonic receiver placement positions, and the pickup means based on signals from the pressure detection means Correction means for removing the fluctuation component based on the intake pulsation from the signal component extracted by, the waveform shaping means for converting the output from the correction means into a pulse signal,
Since the control means for receiving the pulse signal from the waveform shaping means and generating the output signal for engine control and the engine operating state adjusting element for operating in response to the output signal for engine control are provided, It is possible to correct the error and eliminate the control error. Moreover, it is possible to accurately and accurately remove the fluctuation component based on the intake pulsation in real time.

[Brief description of drawings]

FIG. 1 is a schematic view showing an embodiment of the present invention, FIG. 2 is a block diagram showing a circuit configuration of the embodiment, and FIGS. 3 to 5 are Karman vortex interrupt routines of the microcomputer in the embodiment. , A flowchart showing a crank phase interruption routine and a main routine, FIGS. 6 to 9 are characteristic diagrams for explaining the same embodiment, FIG. 10 is a schematic diagram showing another embodiment of the present invention, and FIG. The figure is a block diagram showing the circuit configuration of the same embodiment, FIGS. 12 and 13 are flowcharts showing the main routine and Karman vortex interrupt routine of the microcomputer in the same embodiment, and FIG. 14 is a description of the same embodiment. FIGS. 15 and 16 are schematic diagrams and block diagrams showing the main body and electronic circuit of an example of the Karman vortex air flow meter, and FIG. 17 is a characteristic diagram for explaining the conventional device. . 9 ... Phase comparison circuit, 22 ... Intake passage, 24 ... Karman vortex air flow meter, 25 ... Controller, 26 ... Intake pressure sensor, 51 ... Subtraction circuit.

Front page continuation (72) Inventor Mamoru Sugiura 1st Uzumasa Town, Ukyo-ku, Kyoto City, Kyoto Prefecture Mitsubishi Motors Corporation, Kyoto Works (72) Inventor Yasuhiko Saito 1st Nakasiri, Hashime Town, Aichi Prefecture Mitsubishi Motors Kogyo Kogyo Co., Ltd. (56) References JP-A-56-129729 (JP, A) JP-B-58-15045 (JP, B2)

Claims (1)

[Claims] 1. A throttle valve installed in an intake passage of an engine, a vortex generator installed upstream of the throttle valve in the intake passage, and the intake air between the throttle valve and the vortex generator. An ultrasonic transmitter and an ultrasonic receiver arranged so as to face each other across a passage, and pickup means for extracting a signal component of a frequency corresponding to the number of generated Karman vortices from a signal received by the ultrasonic receiver. , Pressure detecting means for detecting the pressure in the intake passage in the vicinity of the ultrasonic transmitter and ultrasonic receiver installation positions, and to the intake pulsation from the signal component extracted by the pickup means based on the signal from the pressure detecting means. Correction means for removing the fluctuation based on the waveform correction means, a waveform shaping means for converting the output from the correction means into a pulse signal, and a pulse signal from the waveform shaping means. Only the control means for generating an output signal for the engine control, the engine control apparatus characterized by comprising an engine operating condition adjusting element which operates in response to an output signal for the engine control.