JPH0346659B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an engine control device.

[Prior art]

The engine control device according to the present invention includes a fuel injection amount control device, an ignition timing control device, or an ignition timing control device.
There are various types of EGR amount control devices, but for convenience of explanation, a fuel injection amount control device will be explained below as an example.

Recently, in vehicle engines, fuel injection valves have been widely used as fuel supply devices in place of conventional carburetors in order to improve driveability and fuel efficiency. In this system, a fuel injection pulse is created according to the operating state of the engine, and the pulse is applied 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 the amount of intake air, which is a parameter of the engine operating state, and
Alternatively, there is a negative pressure sensor that detects the intake pipe negative pressure, which is also a parameter of the engine operating state, and controls the fuel injection amount based on the air flow sensor output or negative pressure sensor output. When using the latter type of air flow sensor, this becomes intake resistance and causes a decrease in engine output.On the other hand, when using the latter type of negative pressure sensor, there is generally a delay in changes in intake pipe negative pressure due to changes in engine operating conditions. Therefore, there is a problem that a delay occurs in the injection amount control.

Also, as a control device for other engines of this type,
Conventionally, as shown in Japanese Patent Application Laid-Open No. 49-61519, a throttle sensor detects the throttle valve opening, which is also a parameter of the engine operating state, and the fuel injection amount is determined based on the throttle sensor output. In this device, the throttle sensor does not cause intake resistance like the above-mentioned air flow sensor, and the change in the throttle valve opening is proportional to the change in the intake pipe negative pressure. However, since it has a good ability to follow changes in the operating state of the engine, problems such as a decrease in engine output and a delay in injection amount control do not occur.

However, in the device described in the above-mentioned conventional publication, the fuel injection pulse, that is, the control amount of the fuel injection amount, is determined according to the output value of the throttle sensor. There is a problem that control accuracy decreases.

The way to solve this problem is to learn the throttle sensor outputs corresponding to the full opening/closing degree and the full opening degree of the throttle valve, that is, the minimum output value and the maximum output value, and calculate the output value from these two sensor output values. A possible method is to calculate the opening rate of the throttle valve corresponding to an arbitrary throttle sensor output and determine the control amount of the fuel injection amount based on this. In this method, even if the throttle sensor output for the same throttle valve opening changes due to sensor installation errors or individual differences in sensor characteristics, the throttle valve opening rate determined from the sensor output remains constant. Therefore, the problem of decreased control accuracy does not occur.

However, with this method, until the engine is started and the throttle valve is fully opened,
There is a possibility that the value obtained as the output value corresponding to fully opening the throttle valve is significantly different from the output value corresponding to actually fully opening the throttle valve, and the air-fuel ratio may deviate significantly.

[Purpose of the invention]

In view of these problems, the present invention can prevent the control accuracy from decreasing due to sensor installation errors and individual differences in sensor characteristics, and also prevents the control amount from changing significantly even when the full opening degree has not been learned. The purpose of the present invention is to provide an engine control device that does not require the following.

[Structure of the invention]

Therefore, this invention learns the minimum value and maximum value of the throttle sensor output, and by equally dividing this value, detects the opening rate of the throttle valve, and controls the engine based on this. An initial value is set for the output value of the sensor corresponding to full opening, and the engine is controlled using the above initial value until the throttle sensor output after the engine starts detects a throttle valve opening greater than the above initial value. It is something.

That is, in the present invention, as shown in the functional block diagram of FIG. In addition to detecting and storing the output value, the maximum value storage means 25 receives the output of the throttle sensor 23 and detects and stores the maximum output value, and the opening calculation means 26 detects and stores the output of the minimum value storage means 24 and the maximum value storage means 25. Then, the two output values are determined as the output values of the throttle sensor 23 corresponding to the fully closed and fully opened opening degrees of the throttle valve, and the throttle valve corresponding to the arbitrary output value of the throttle sensor 23 is determined based on the two output values. The opening degree is calculated, and the various control means 27 receive the output of the opening degree calculation means 26 and control the engine according to the output. At this time, the allowable value setting means 28 sets the output of the maximum value storage means 25 to the vicinity of the throttle fully open. The opening degree is forcibly set to an initial value equal to or higher than a predetermined opening degree.

〔Example〕

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

2 to 7 show an engine control device according to an embodiment of the present invention. In Figure 2, 1
1 is an engine, and a throttle valve 3 is provided in the middle of an intake passage 2 of the engine 1, and a fuel injection valve 4 is arranged in the intake passage 2 on the downstream side of the throttle valve 3. Further, a spark plug 6 is attached to the engine 1 facing the combustion chamber 5, and a distributor 8 that rotates in synchronization with the crankshaft 7 of the engine 1 is provided. Ignition coil 1 due to operation
The high voltage generated at zero is applied to the spark plug 6.

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

FIG. 3 shows a more detailed configuration of the control unit 13. In the figure, the same reference numerals as in FIG.
16 is an A/D converter that A/D converts the output of the throttle sensor 11, 17 is a counter, 18 is a timer, and 19 is a fuel injection valve according to the set time of the timer 18. 4, a drive circuit that drives 20, a CPU that performs predetermined arithmetic processing,
21 is the arithmetic processing program of the CPU 20 (4th
The ROM 22, which stores data such as
This is a RAM that stores 0 calculation results, etc.

And the above CPU 20 is the throttle sensor 1
The throttle valve opening rate corresponding to an arbitrary output value of the throttle sensor 11 is calculated from the two output values by learning the minimum output value and maximum output value of 1, and according to this and the engine speed. The fuel injection amount is controlled by calculating the fuel injection amount and giving it to the timer 18 to cause the fuel injection valve 4 to inject and supply an amount of fuel according to the operating state of the engine,
In addition, at this time, when learning the minimum output value and maximum output value of the throttle sensor 11, the output values include values below a predetermined opening degree near the idle opening degree and values above the predetermined opening degree near the fully open opening degree. Learning is performed such that the correction is output, and the correction is stopped when the amount of correction of the minimum output value and the maximum output value is equal to or greater than a predetermined value.

Note that in the above configuration, the timer 1
8. The drive circuit 19 and the CPU 20 serve as various control means 27 shown in FIG.
0 realizes the functions of the minimum value storage means 24, maximum value storage means 25, opening calculation means 26, and tolerance value setting means 28 shown in FIG.

Next, the operation will be explained using FIGS. 4 to 7. Here, Figure 4 is a flowchart of the background routine of CPU20, and Figure 5 is a flowchart of the background routine of the CPU20.
The flowchart of the interrupt routine of the CPU 20 is shown in Fig. 6, the pulse width map of the fuel injection pulse with the throttle valve opening rate and the engine speed as parameters, and Fig. 7 is the throttle valve opening and the throttle sensor. The relationship with the output is shown below.

When the engine starts, the CPU 20 executes a background routine process, and first sets an initial value Iθdl (see Fig. 7) corresponding to a predetermined opening near the idle opening in the fully closed opening register θidl, and The initial value Iθwot corresponding to a predetermined opening near the fully open opening is set in the opening register θwot (see Figure 7).
After setting (step 30), the A/D conversion output θthr (see FIG. 7) of the throttle sensor 11 is read and it is determined whether or not this is smaller than the value of the fully closed opening register θidl (step 31, 32).
When the engine is idling, the throttle sensor output θthr is smaller than the value of the fully closed register θidl, so the difference between the throttle sensor output θthr and the value of the fully closed register θidl is less than the set value θnois. After determining whether the throttle sensor output θthr is smaller than the lower limit value θmin (see Fig. 7) of the fully closed opening (step 34), if it is larger, the throttle sensor output θthr is Rewrite the value of the closed opening register θidl with the current throttle sensor output θthr (step 35), and use the values of the fully closed register θidl and the fully open register θwot to set the throttle valve corresponding to the throttle sensor output θthr. Opening rate θ (θthr−θidl)/(θwot−θidl)
×100) (step 36), read the engine speed Ne, and calculate the fuel injection amount TOUT according to this engine speed Ne and the throttle valve opening rate θ.
is obtained from the map (see Fig. 6), and the value of the fully closed opening register θidl is learned and updated one after another in this way. Also, while updating the fully closed position register θidl, if the throttle sensor output θthr becomes smaller than the fully closed position lower limit value θmin for some reason,
Generate the lower limit value θmin as the throttle sensor output θthr (step 39), and then proceed to step 3 described above.
Execute processes 5 to 38. Also, when the throttle sensor output θthr deviates from the value of the fully closed opening register θidl during idling (θidl - θthr
≧θnois), it is determined that the throttle sensor 11 is erroneously detected due to noise, etc., and the value of the fully closed opening register θidl is generated as the throttle sensor output θthr (step 40), and the processing of steps 36 to 38 described above is performed. Execute.

Next time the engine returns to normal operation, the CPU
Step 20 determines whether the throttle sensor output θthr is larger than the value of the fully open register θwot (step 41), and the process continues in steps 41, 36 to 38 until the throttle valve 3 becomes fully open (θthr≧θwot).
When the throttle valve is fully opened, it is determined whether the difference between the throttle sensor output θthr and the fully open register θwot is smaller than the set value θnois (step 42), and the throttle sensor output is θthr is the upper limit value θmax of full opening (see Figure 7)
(Step 43), and if it is smaller, the value of the fully open register θwot is rewritten with the current throttle sensor output θthr (Step 44), and the processes of Steps 36 to 38 described above are executed. In this way, the value of the fully open register θwot is updated one after another. Furthermore, while updating the value of the full-open position register θwot, if the throttle sensor output θthr exceeds the full-open position upper limit value θmax for some reason, this upper limit value θmax is generated as the throttle sensor output θthr (step 45). ), and then the processes of steps 44, 36 to 38 described above are executed. Also, if the throttle sensor output θthr deviates from the value of the fully open register θwot when the throttle valve is fully open (θthr -
If θwot≧θnois), it is determined that the throttle sensor 11 is erroneously detected due to noise, etc., and the value of the fully open register θwot is generated as the throttle sensor output θthr (step 46), and the process is repeated in steps 36 to 3 described above.
8 will be executed.

Also, while executing the background routine processing in this way, the rotation angle of the engine changes.
When TDC is reached, the CPU 20 executes the interrupt routine shown in FIG.
The interrupt cycle is calculated from the difference between this value and the counter value Cbef at the previous interrupt, and the engine rotation speed Ne is calculated (step 47,
48), after rewriting the counter value Cbef at the previous interrupt with the current counter value C (step 4).
9) The fuel injection amount TOUT obtained in the background routine is set in the timer 18 (step 50), and the process returns to the background routine, whereby the drive circuit 19 adjusts the engine's TDC.
The fuel injection valve 4 is driven in synchronization with the signal, and the engine is supplied with engine speed Ne and throttle valve opening rate θ.
An amount of fuel corresponding to the amount is injected and supplied, and the air-fuel ratio of the air-fuel mixture is controlled to the target air-fuel ratio.

In the folding of this embodiment as described above, the minimum output value and maximum output value of the throttle sensor are learned and the two
Since the throttle valve opening rate is calculated from the two output values and the fuel injection amount is determined according to this throttle valve opening rate, the accuracy is not affected by sensor installation errors or individual differences in sensor characteristics. The fuel injection amount can be well controlled and the target air-fuel ratio can be obtained.

In addition, with this device, when learning the throttle sensor output, upper and lower limits (initial value of fully closed position and initial value of fully opened position) are set for the minimum output value and maximum output value, so that it can be adjusted depending on the engine operating state. Therefore, the throttle valve opening rate will not be significantly deviated, and the air-fuel ratio will not vary significantly.

Furthermore, with this device, when correcting the fully closed or fully open position, if the amount of correction (difference between the throttle sensor output and the value of the fully closed or fully open position register) is large, the correction is not performed. It is possible to prevent deviations in the throttle valve opening rate due to erroneous detection by the throttle sensor due to noise or the like, and thereby also to suppress deviations in the air-fuel ratio.

In the above embodiment, the case where the fuel injection amount is controlled has been described, but the present invention can of course also be applied to the case where the ignition timing or the EGR amount is controlled. Further, in the above embodiment, the case where the throttle sensor output is the minimum when idling and the maximum when fully open has been described, but it may be configured to be the maximum when idling and the minimum when fully open.

〔Effect of the invention〕

As described above, according to the engine control device according to the present invention, the opening rate of the throttle valve is detected by learning the minimum value and maximum value of the throttle sensor output and dividing the value equally. , while controlling the engine based on this, a lower limit value is set for the output value corresponding to a fully open throttle valve, and the lower limit is set until the throttle sensor output detects a throttle valve opening that is greater than the lower limit value after the engine has started. Since the engine is controlled using the value, it is possible to improve the accuracy of engine control, and it is also possible to prevent a large deviation in the control amount due to unlearning of the full opening degree.

[Brief explanation 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, FIG. 3 is a more detailed configuration diagram of the control unit 13 in the above device, and FIGS. Figure 6 is a flowchart of the background routine and interrupt routine of the CPU 20 in the engine, Figure 6 is a map of the fuel injection amount using the engine speed and throttle valve opening rate as parameters, Figure 7 is the flowchart of the FIG. 2 is a diagram showing characteristics of throttle valve opening and throttle sensor output for explaining the operation of the CPU 20. FIG. 23...Throttle sensor, 24...Minimum value storage means, 25...Maximum value storage means, 26...Opening degree calculation means, 27...Various control means, 28...Tolerance value setting means, 1...Engine, 11...Throttle sensor, 1
8...Timer, 19...Drive circuit, 20...CPU.

Claims (1)

[Scope of Claims] 1. A throttle sensor that detects the throttle valve opening of the engine; minimum value storage means that receives the output of the throttle sensor and detects and stores a minimum output value; maximum value storage means for detecting and storing the maximum output value; and a throttle sensor output value corresponding to the fully closed and fully opened opening degrees of the throttle valve, which receives the outputs of the minimum value storage means and the maximum value storage means and converts both output values into the output values of the throttle valve. an opening calculating means for determining a throttle valve opening corresponding to an arbitrary output value of the throttle sensor from the two output values; and receiving an output from the opening calculating means and controlling the engine according to the output. The maximum value in the maximum value storage means is forcibly set to the initial value until the throttle sensor output after the engine starts detects a throttle valve opening greater than a preset initial value. 1. A control device for an engine, comprising: a permissible value setting means for setting a permissible value.