JP2502500B2 - Engine controller - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an engine control device.

[Prior art]

The engine control device according to the present invention includes various devices such as a fuel injection amount control device, an ignition timing control device, an EGR amount control device, and the like. However, for convenience of description, the fuel injection amount control device will be taken as an example below. Explain.

2. Description of the Related Art Recently, in vehicular engines, fuel injection valves tend to be widely used as fuel supply devices in place of conventional carburetors from the viewpoint of improving drivability and fuel efficiency. Then, a fuel injection pulse is created according to the operating state of the engine, and this is added to the fuel injection valve to control the fuel injection amount.

As an example of such an engine control device, conventionally, an air flow sensor detects an intake air amount which is a parameter of an engine operating state, or a negative pressure sensor also detects an intake air amount which is a parameter of an engine operating state. There is a system in which the pipe negative pressure is detected and the fuel injection amount is controlled based on the output of the air flow sensor or the output of the negative pressure sensor. However, when the former air flow sensor is used, this becomes intake resistance and becomes the engine output. On the other hand, when the latter negative pressure sensor is used, the change in the intake pipe negative pressure with respect to the change in the operating state of the engine is generally delayed, which causes a problem in that the injection amount control is delayed.

In addition, as a control device for other engines of this type, conventionally,
For example, as disclosed in Japanese Patent Laid-Open No. 49-61519, a throttle sensor detects the throttle valve opening, which is also a parameter of the operating state of the engine, and controls the fuel injection amount based on the output of the throttle sensor. In this device, the throttle sensor does not become an intake resistance unlike the above-mentioned air flow sensor, and the change of the throttle valve opening is compared with the change of the intake pipe negative pressure, and Since it has good followability to changes in state,
There is no problem such as a decrease in engine output or a delay in injection amount control.

However, in the device disclosed in the above-mentioned conventional publication, the control amount of the fuel injection pulse, that is, the fuel injection amount is determined according to the output value of the throttle sensor. Therefore, the control is caused due to the mounting error of the sensor and the individual difference of the sensor characteristics. There is a problem that the accuracy is reduced.

And as a method for solving such a problem, the throttle sensor output corresponding to the fully closed opening and the fully opened opening of the throttle valve, that is, learning the minimum output value and the maximum output value,
A method is conceivable in which the opening ratio of the throttle valve corresponding to an arbitrary throttle sensor output is calculated from these two sensor output values and the control amount of the fuel injection amount is determined based on this. In this method, even if the throttle sensor output for the same throttle valve opening changes due to sensor installation error and individual differences in sensor characteristics, the throttle valve opening ratio obtained from the sensor output must be constant. Therefore, the problem of deterioration of control accuracy does not occur.

However, in this method, when the throttle sensor is erroneously detected due to some cause, such as noise, while the minimum output value and the maximum output value of the throttle sensor are being learned, the original throttle valve is fully closed or fully opened. An output value that deviates significantly from the throttle sensor output value is learned, and as a result, a difference occurs in the throttle valve opening rate, which may cause the air-fuel ratio to deviate from the target value.

[Object of the Invention]

In view of such a problem, the present invention provides a control device for an engine that can prevent a decrease in control accuracy due to a sensor mounting error or an individual difference in sensor characteristics without causing a malfunction due to noise or the like. It is a thing.

[Structure of Invention]

Therefore, the present invention learns the minimum value and the maximum value of the throttle sensor output, detects the opening ratio of the throttle valve by equally dividing the interval, and controls the engine based on this to detect the minimum or maximum output. When the value changes by a predetermined value or more per unit time, learning is stopped.

That is, according to the present invention, as shown in the functional block diagram of FIG. 1, the throttle sensor 23 detects the throttle valve opening of the engine, and the minimum value storage means 24 detects the throttle sensor.
Receives the output of 23, detects and stores the minimum output value,
The minimum value storage means 25 receives the output of the throttle sensor 23 to detect and store the maximum output value, and the opening degree calculation means 26 receives the outputs of the minimum value storage means 24 and the maximum value storage means 25 and outputs both output values to the throttle valve. Is determined as the output value of the throttle sensor 23 corresponding to the fully closed and fully opened positions of the throttle sensor 23, the throttle valve opening corresponding to an arbitrary output value of the throttle sensor 23 is calculated from the two output values, and various control means 27 are used. When the output of the opening degree calculation means 26 is received and the engine is controlled according to the output, when the change in the minimum output value or the maximum output value of the throttle sensor 23 per unit time is a predetermined value or more, the stop means 28 is set to the minimum. The storage operation of the value storage means 24 or the maximum value storage means 25 is stopped.

〔Example〕

 Embodiments of the present invention will be described below with reference to the drawings.

2 to 7 show an engine controller according to an embodiment of the present invention. In FIG. 2, reference numeral 1 denotes an engine, a throttle valve 3 is provided in the intake passage 2 of the engine 1, and a fuel injection valve 4 is provided in the intake passage 2 downstream of the throttle valve 3. . A spark plug 6 is attached to the engine 1 so as to face the combustion chamber 5, while a crankshaft 7 of the engine 1 is provided with a distributor 8 that rotates in synchronization with the crankshaft 7. The distributor 8 operates by an igniter 9 to activate an ignition coil. The high voltage generated at 10 is applied to the spark plug 6.

In the figure, 11 is a throttle sensor that detects the opening of the throttle valve 3, 12 is a crank angle sensor that detects the rotation angle of the crankshaft 7, and 13 is the output of the various sensors described above, and controls the fuel injection amount. It is a control unit.

Further, FIG. 3 shows a more detailed structure of the control unit 13. In the figure, the same reference numerals as those in FIG. 2 indicate the same elements as in the same figure, 14 and 15 are input circuits into which the outputs of the throttle sensor 11 and the crank angle sensor 12 are input, and 16 is the output of the throttle sensor 11 A / D converter for D conversion, 17 is a counter, 18 is a timer, 19 is a drive circuit that drives the fuel injection valve 4 according to the set time of the timer 18, 20 is a CPU that performs predetermined arithmetic processing, and 21 is a CPU 20. Program for arithmetic processing (4th
(See FIG. 5, FIG. 5) and the like are stored in the ROM, and 22 is a RAM that is backed up by a battery and stores input information and the calculation result of the CPU 20.

Then, the CPU 20 learns the minimum output value and the maximum output value of the throttle sensor 11 and calculates the throttle valve opening ratio corresponding to an arbitrary output value of the throttle sensor 11 from the two output values. The fuel injection amount is controlled according to the number of revolutions and is supplied to the timer 18 so that the fuel injection valve 4 is supplied with an amount of fuel corresponding to the operating state of the engine. that time,
At the time of learning the minimum output value and the maximum output value of the throttle sensor 11, the output value should be a value equal to or smaller than a predetermined opening near the idle opening or a value equal to or larger than a predetermined opening near the fully open opening. Also, when the correction amount of the minimum output value and the maximum output value is equal to or larger than a predetermined value, the learning is stopped.

In the above structure, the timer 18, the drive circuit 19 and the CPU 20 serve as various control means 27 shown in FIG. 1, and the CPU 20 has the minimum value storage means 24 shown in FIG.
The functions of the maximum value storage means 25, the opening degree calculation means 26, and the stop means 28 are realized.

Next, the operation will be described with reference to FIGS. 4 to 7. Here, FIG. 4 is a flowchart of the background routine of the CPU 20, FIG. 5 is a flowchart of the interrupt routine of the CPU 20, and FIG. 6 is a flowchart of the fuel injection pulse with the throttle valve opening rate and the engine speed as parameters. FIG. 7 shows a pulse width map, and FIG. 7 shows the relationship between the throttle valve opening and the throttle sensor output.

When the engine is started, the CPU 20 executes the processing of the background routine, and first, the initial value Iθidl corresponding to the predetermined opening degree near the idle opening degree is stored in the fully closed opening degree register θidl.
(See FIG. 7) is set, and the initial value Iθw corresponding to the predetermined opening near the full opening is registered in the full opening register θwot.
After setting ot (see FIG. 7) (step 30), read the A / D conversion output θthr (see FIG. 7) of the throttle sensor 11 and determine whether this is smaller than the value of the fully closed opening register θidl. The judgment is made (steps 31, 32). Since the throttle sensor output θthr is smaller than the value of the fully closed opening register θidl when the engine is idle, is the difference between the throttle sensor output θthr and the value of the fully closed opening register θidl smaller than the set value θnois? After determining whether or not (step 33), it is determined whether or not the throttle sensor output θthr is larger than the lower limit value θmin (see FIG. 7) of the fully closed opening (step 34). Register θ
The value of idl is rewritten with the current throttle sensor output θthr (step 35), and the throttle valve opening rate θ (= (=) corresponding to the throttle sensor output θthr is calculated using the values of the fully closed opening register θidl and the fully opened opening register θwot. (Θthr−
θidl) / (θwot−θidl) × 100) is calculated (step
36), the engine speed Ne is read, and the fuel injection amount TOU according to the engine speed Ne and the throttle valve opening ratio θ
T is obtained from the map (see FIG. 6), and thus the value of the fully closed opening degree register θidl is learned and updated one after another. Also, while updating the fully closed position register θidl,
When the throttle sensor output θthr becomes smaller than the fully closed opening lower limit value θmin for some reason, this lower limit value θmin is generated as the throttle sensor output θthr (step 39),
After that, the processes of steps 35 to 38 described above are executed. When the throttle sensor output θthr deviates from the value of the fully closed opening register θidl during idling (θidl-θ
thr ≥ θnois), throttle sensor 1 due to noise etc.
Judging that it is an erroneous detection of 1, the value of the fully closed opening register θidl is generated as the throttle sensor output θthr (step 40),
The processing of steps 36 to 38 described above is executed.

Next, when the engine is in the normal operating state, the CPU 20 determines whether or not the throttle sensor output θthr is larger than the value of the full opening degree register θwot (step 41), and until the full opening degree of the throttle valve 3 is reached (θthr ≧ θ wot) Step 4
After executing the processing of 1,36 to 38, and when the throttle valve fully open opening time is reached, after determining whether the difference between the throttle sensor output θthr and the fully open opening register θwot is smaller than the set value θnois (step 42), It is judged whether or not the throttle sensor output θthr is smaller than the upper limit value θmax (see FIG. 7) of the full opening degree (step 43). If it is smaller, the value of the full opening degree register θwot is used as the current throttle sensor output θthr. Rewriting (step 44), the processes of steps 36 to 38 described above are executed, and thus the value of the full opening degree register θwot is updated one after another. In addition, the full opening register θ
While the wot value is being updated, if for some reason the throttle sensor output θthr becomes equal to or greater than the fully open opening upper limit value θmax, the upper limit value θmax of θthr is generated as the throttle sensor output (step 45). Perform the processing of 44, 36-38. Further, when the throttle sensor output θthr deviates greatly from the value of the full opening degree register θwot at the time of the throttle valve fully opening degree (θthr−θwot ≧ θnois),
The throttle sensor output θthr is judged to be the false detection of the throttle sensor 11 due to noise, etc.
The value of ot is generated (step 46) and the above steps 36-38 are performed.
Will be executed.

When the engine rotation angle becomes TDC while executing the background routine processing in this way, the CPU 20 executes the interrupt routine processing shown in FIG. 5 and reads the value C of the counter 17. Then, the interrupt cycle is obtained from the difference between this and the counter value Cbef at the time of the previous interrupt, and the engine speed Ne is calculated (step 4
7, 48), after rewriting the counter value Cbef at the time of the previous interruption with the current counter value C (step 49), the fuel injection amount TOUT obtained in the background routine is set to the timer 1
Set it to 8 (step 50) and return to the background routine processing, which causes the drive circuit 19 to
The fuel injection valve 4 is driven in synchronization with the TDC signal, fuel is injected and supplied to the engine in an amount according to the engine speed Ne and the throttle valve opening ratio θ, and the air-fuel ratio of the air-fuel mixture becomes the target air-fuel ratio. Will be controlled.

In the apparatus of the present embodiment as described above, the minimum output value and the maximum output value of the throttle sensor are learned, the throttle valve opening rate is calculated from the two output values, and the fuel injection is performed according to this throttle valve opening rate. Since the amount is determined, the fuel injection amount can be accurately controlled and the target air-fuel ratio can be obtained without being affected by the mounting error of the sensor and the individual difference in the sensor characteristics.

Further, in this device, when the fully closed opening and the fully opened opening are corrected, the correction is not performed when the correction amount (difference between the throttle sensor output and the fully closed or fully opened opening register) is large. It is possible to prevent deviation of the throttle valve opening ratio due to erroneous detection of the throttle sensor due to noise or the like, and suppress deviation of the air-fuel ratio.

Furthermore, in this device, when learning the throttle sensor output, the upper and lower limits of the minimum output value and the maximum output value (initial value of the fully closed opening and initial value of the fully opened opening) are set. The degree of opening does not significantly change, and the air-fuel ratio does not significantly change.

In the above embodiment, the case where the fuel injection amount is controlled has been described, but the present invention can be applied to the case where the ignition timing, the ERG amount, etc. are controlled. Further, in the above embodiment, the case where the throttle sensor output is minimum at idle and maximum at full open has been described, but it may be maximum at idle and minimum at full open.

〔The invention's effect〕

As described above, according to the engine control device of the present invention, the minimum value and the maximum value of the throttle sensor output are learned, and the opening ratio of the throttle valve is detected by equally dividing the interval, and While controlling the engine based on
Since learning is stopped when the minimum or maximum output value changes by a predetermined value or more per unit time, there is an effect that the engine control accuracy can be improved without malfunctioning due to noise or the like.

[Brief description of drawings]

FIG. 1 is a functional block diagram showing the configuration of the present invention, FIG. 2 is a schematic configuration diagram of an engine control device according to an embodiment of the present invention, and FIG. 3 is a control unit 13 in the above device.
Fig. 4 and Fig. 5 are flow charts showing the background routine and interrupt routine of the CPU 20 in the control unit 13, respectively. Fig. 6 shows the engine speed and throttle valve opening. FIG. 7 is a diagram showing a map of the fuel injection amount using the
The figure is a diagram showing the characteristics of the throttle valve opening and throttle sensor output for explaining the operation of the CPU 20. 23 ... Throttle sensor, 24 ... Minimum value storage means, 25 ...
... maximum value storage means, 26 ... opening degree calculation means, 27 ... various control means, 28 ... stop means, 1 ... engine, 11 ... throttle sensor, 18 ... timer, 19 ... driving circuit, 20 ......
CPU.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Manabu Arima No. 3 Shinchi Fuchu-mura, Aki-gun Mazda Stock Company (56) References JP-A-55-138101 (JP, A) JP-A-56-107926 ( JP, A) JP 58-10131 (JP, A) JP 58-170839 (JP, A)

Claims (1)

(57) [Claims] 1. A throttle sensor for detecting an opening of a throttle valve of an engine, a minimum value storage means for detecting and storing a minimum output value by receiving an output of the throttle sensor, and a maximum output value by receiving an output of the throttle sensor. The maximum value storage means to be stored and the outputs of the minimum value storage means and the maximum value storage means are received, and both output values are discriminated as output values of the throttle sensor corresponding to the fully closed and fully opened positions of the throttle valve.
An opening calculation means for calculating a throttle valve opening corresponding to an arbitrary output value of the throttle sensor from one output value, and various control means for receiving an output of the opening calculation means and controlling an engine according to the output. And a stop means for stopping the storage operation of the minimum value storage means or the maximum value storage means when the change in the minimum output value or the maximum output value of the throttle sensor per unit time is equal to or more than a predetermined value. Engine control unit.