JPH01106959A - Control device for internal combustion engine - 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] (Industrial Application Field) The present invention relates to a control device for an internal combustion engine, and more specifically, to improve transient control characteristics by eliminating detection delay of a pressure sensor during transient operating conditions of the engine. The present invention relates to a control device for an internal combustion engine.

(Prior Art) In internal combustion engines, especially internal combustion engines for automobiles, operation is controlled by determining control values such as fuel injection amount and ignition timing based on engine speed and engine load condition. Therefore, the engine load condition is detected through the intake pressure or intake air amount, but when the engine load is detected through the intake pressure, it is difficult to detect the engine load during transient periods, especially when the vehicle fully closes the throttle valve. When the throttle valve is suddenly opened and the vehicle is accelerated from a low intake pressure state where the vehicle is running at a relatively low speed, there is an inconvenience that the pressure sensor has a detection delay. Therefore, in the past, the control value was corrected to match the engine's requirements, and in fuel injection control, acceleration increase correction was applied to the basic injection amount, and in ignition timing control, the ignition timing was retarded during acceleration. I made corrections and prepared for knocking. An example of ignition timing control is the technique described in Japanese Patent Application Laid-Open No. 57-99269.

(Problem to be solved by the invention) However, in the conventional case, the detection delay of the sensor was compensated by correcting the control value, so the control value was calculated from the engine speed and the load condition. Then, a transient correction has to be applied to it, which has the disadvantage of complicating calculations. In particular, when transient operation is repeated, corrections become frequent and it takes time to calculate the control value, resulting in a delay in the control system, deteriorating the responsiveness or drivability of transient control, and causing similar problems. For this reason, it has been difficult to quickly suppress knocking, which tends to occur during transient periods. Furthermore, as a result of the complicated calculations, even when an on-vehicle computer is used, its memory capacity must necessarily be increased, which is a secondary drawback.

Therefore, an object of the present invention is to eliminate such drawbacks of the prior art, and to solve the problem of a change in the load state of the engine during a transient state, particularly when there is a sudden acceleration from a low speed running state where the detection delay of the sensor is noticeable. is determined accurately in advance through experiments and stored as data, and when such an operating condition is detected while driving, this data is used as the engine load parameter in place of the pressure sensor actual measurement value, and based on it. By configuring the control value to be calculated, it is no longer necessary to perform transient correction to correct detection delay, simplifying the control value calculation process and improving transient control responsiveness, drivability, and knocking countermeasures. An object of the present invention is to provide a control device for an internal combustion engine.

(Means and operations for solving the problems) In order to achieve the above object, the present invention has been developed as shown in FIG. A detection means 10, an intake pressure detection means 12 disposed at an appropriate position in the intake passage of the internal combustion engine to detect the pressure of air taken into the engine, outputs of the engine speed detection means and the intake pressure detection means are inputted. A control device for an internal combustion engine comprising a control value determining means 14 that determines a control value for engine operation based on the control value, and an actuator means 16 for operating the engine that operates by inputting the output of the control value determining means, which is disposed in an engine intake passage. Throttle valve opening detection means 1 for detecting the opening of the throttle valve
8 and the throttle valve opening detecting means and the engine rotation speed detecting means -5 = Input the output of the stage and calculate the rate of change of the throttle valve from the output of the throttle valve opening detecting means, and if the calculated value is less than or equal to the predetermined rotation speed. and intake pressure setting means 19 for setting the intake pressure determined from the throttle valve opening when the rate of change is equal to or higher than a predetermined rate of change.
The control value determining means is configured to determine the control value based on the set value when the intake pressure setting means sets the intake pressure.

(Example) Hereinafter, the present invention will be described in detail with reference to FIG. 2 and subsequent figures.

FIG. 2 shows the overall configuration of a control device for an internal combustion engine according to the present invention. To explain it according to the figure, a multi-cylinder internal combustion engine 20 consisting of four cylinders etc. is equipped with an intake air passage 22, and air flows in from an air cleaner 24. The air is introduced into the combustion chamber 32 of the - cylinder 30 through the intake manifold 28 while its flow rate is adjusted by the throttle valve 26. The intake air passage 22 is connected to a pipe 34 and branched off at an appropriate position downstream of the throttle valve 26, and the above-mentioned intake pressure detection means for detecting the absolute pressure of the intake air passage is located near the terminal end of the branch passage 61. A pressure sensor 36 is provided to detect the load condition of the engine. A throttle sensor 38, which is a potentiometer and serves as the aforementioned throttle valve opening detection means, is connected to the throttle valve 26, and detects the opening of the throttle valve 26, which opens and closes in conjunction with an accelerator pedal (not shown) on the driver's seat of the vehicle. To detect. Further, a water temperature sensor 42 is provided near the cooling water passage 40 of the cylinder 30 to detect the temperature of the engine cooling water, and an intake temperature sensor 44 is provided at an appropriate position downstream of the throttle valve 26 in the intake air passage 22. Detects the temperature of the air that the engine takes in. These pressure sensor 36, throttle sensor 38, water temperature sensor 42
The output of the intake air temperature sensor 44 is input to the control unit 46, where it is amplified to an appropriate level by the level correction circuit 48, and then input to the microcomputer 50. The microcomputer 50 has an A/D conversion circuit 5
0a 1 person interface 50b, CPU 50c, R
It mainly includes an OM50d, a RAM50e, and an output interface 50f, as well as a counter and a flag register (both not shown), which will be described later. The output of the level correction circuit 48 mentioned above is
After being inputted to the /D conversion circuit 50a and converted into a digital value every predetermined time or predetermined angle, it is temporarily stored in the RAM 50e.

Further, a distributor 54 is provided near the internal combustion engine 20, and inside thereof there is a magnet that rotates in synchronization with the rotation of a crankshaft (not shown) that rotates with the vertical movement of a piston 56, and a magnet that rotates in synchronization with the rotation of a crankshaft (not shown). A crank angle sensor 58, which is the above-mentioned engine rotational speed detecting means and consists of a magnetic pickup or the like arranged facing each other, is housed, and outputs a pulse signal at every predetermined crank angle. The output of the crank angle sensor 58 is also input to the control unit 46, and its waveform shaping circuit 60
After waveform shaping, the signal is input to the microcomputer 50 and temporarily stored in the RAM 50e.

The microcomputer 50 measures the time interval of the output value of the crank angle sensor 58 to calculate the engine speed, and also calculates the amount of change in the output of the throttle sensor 38 per predetermined time to calculate the rate of change, and performs these calculations. The ignition timing is calculated as an engine operation control value from the value and other sensor outputs, and is output to the first output circuit 66 via the output interface circuit 50f, and the ignition coil (
(not shown) to generate a high voltage, which is sent to the ignition brush 68 via the aforementioned distributor 54 to ignite the air-fuel mixture in the combustion chamber 32. Further, the microcomputer 50 further calculates the fuel injection amount and calculates the second
The fuel is outputted to an output circuit 70, and fuel is supplied through an injection valve 74 provided near the combustion chamber 32 through a fuel injection device 72 consisting of a solenoid valve or the like. In the above configuration, the microcomputer 50 corresponds to the above-mentioned control value determining means and the intake pressure setting means, and the ignition system after the first output circuit 66 and the fuel injection system after the second output circuit 70 correspond to the above-described actuator. It corresponds to the means.

=9- Next, the operation of the internal combustion engine control device according to the present invention will be explained with reference to the flow chart in FIG. Note that this program is activated at predetermined angle intervals near the TDC of each cylinder.

First, at 5100, the microcomputer 50 determines whether the current engine speed Ne calculated from the output of the crank angle sensor 58 is below a predetermined engine speed Nerefl. This predetermined rotational speed Neref is set to a value that is at a relatively low rotational speed, such as 2000 rpm, to the extent that the above-mentioned problem due to the throttle valve opening suddenly during driving occurs at that rotational speed. Engine speed is 200
If it is determined that it is less than Orpm, then 51
In 02, the output value TW of the water temperature sensor 42 described above is set to R.
It is read from AM50e and it is determined whether or not it exceeds a predetermined value Twref. This is to check whether the engine has warmed up, so the predetermined value is, for example, 7.
The temperature shall be 5°C. If it is confirmed that it has been warmed up,
Subsequently, at 5104, the rate of change Δ of the throttle valve 26 is
It is determined whether θth is greater than or equal to a predetermined value Δθthref. Since this is to detect sudden acceleration from a low speed running state, the predetermined value is appropriately set to a value sufficient to detect this. 8 if a sudden acceleration state is detected in 5104.
At 106, a counter is set. This counter is a down counter, and the set value is, for example, "12'". This counter value is determined by this program as described below.
It is decremented by ``1'' each time it is activated.

Next, the process proceeds to 8108, where the engine speed is again compared with the second predetermined speed Neref2, for example, 11000 rpm, and if it is less than 11000 rpm, the engine speed is shifted to 5llO and the engine speed is changed to the first
The intake pressure PbaO value is searched by referring to the table value of , and if it is determined that it exceeds 11000 rpm, the process proceeds to 5112 and the intake pressure value is searched based on the second table value. FIG. 4 is an explanatory graph showing these table values. The feature of the present invention is that the detection delay of the pressure sensor 36 that detects the engine load state during transient periods is corrected after calculating the control value based on the actual measured value as in the prior art. Instead, the intake pressure in a transient state is accurately determined through experiments in advance and stored in the ROM 50d of the microcomputer, and when a transient state is detected, it is artificially set in place of the actual measured value by the pressure sensor. The point is that the control value is calculated using the data value obtained. Since the intake pressure differs depending on the engine speed, 11000 rpm in 8108
The system is configured so that the rotation range is divided into two rotation ranges by p, and one of the rotation ranges is selected.Since the rotation range is more directly affected by the throttle valve opening, the system is configured to search according to the opening detected by the throttle sensor 38. It is something.

After searching for the intake pressure value from either table in 5110 or 112, the down counter is subsequently decremented in 3114, and control values such as fuel injection amount and ignition timing are calculated in 5116. The control value is calculated from the engine speed and the engine load, but since the table value is used as the engine load, it is no longer necessary to correct it. It is sufficient to consider only incidental matters such as correction. If it is determined in 5104 that there is no rapid acceleration, it is subsequently determined in 5118 whether the counter value has reached zero, and if it has not reached zero, the process moves to 5108 and the intake pressure value is determined. Use the table value as . This is to prevent engine control hunting by continuing control based on the table value since sensor response delay remains in the following predetermined TDC section even after rapid acceleration has ended. In this sense, the counter is not limited to one that counts the number of TDCs, but may also be one that measures a predetermined time. If it reaches zero, the effect of sudden acceleration has ended and there is no need to rely on the table value, so the counter is reset to zero at 5120, and the control value is calculated at 5122 using the pressure as the intake pressure as in the prior art. The actual value actually detected by the sensor 36 is used. Also, at 5100, the engine speed is 200O
The same applies when the engine speed exceeds the rpm, and warm-up correction is required even when it is determined in 1S102 that the engine is warming up, so the operations at 3120° and 5122 are similarly followed.

In the case of this embodiment, as mentioned above, during sudden acceleration, a value set in advance through experiments is used as the intake pressure value, rather than an actually measured value, and the control value is calculated by using the set value to represent the load state of the engine. Therefore, it is no longer necessary to apply acceleration correction to it, which simplifies the calculation process and reduces calculation time.
Furthermore, since there is no delay in the control system, control responsiveness and drivability during transient times are improved, and knocking can be quickly avoided. or,
The microcomputer 50 also uses RAM for calculations.
This has the advantage that the storage capacity of 50e can be reduced and the cost can be reduced.

In addition, in the above flow chart, in 8110.112, one of the two tables is selected according to the engine speed to search for the intake pressure, but if three or more of the above tables are selected, Furthermore, the number of tables may be one, and the first and second table values (or similar characteristic values) shown by solid lines and broken lines in FIG. 4 may be used as upper and lower limits. The intake pressure may be determined more precisely by interpolating the engine speed between the two.

FIG. 5 is a flowchart showing another example of the operation of the device according to the present invention.
It is a chart. To explain mainly the differences from the first operation example, the engine rotation speed is set to the first predetermined rotation speed N eref 1
Starting from the step of comparing the second predetermined rotation speed Ner
After reaching the step of comparing with ef2 (S200-20
8) In 5212, it is determined whether or not a fuel cut was made at the previous or previous program startup, and if so, the flag register is turned on in 5214, and then the table value is set in 8216 as in the first embodiment. In addition to searching, even if it is determined in 5212 that there is no fuel cut, it is subsequently determined in 8218 whether or not the flag register is turned on, and if it is turned on, the table value is similarly substituted for the actual measured value. (3216). That is, when sudden acceleration occurs after the fuel cut state or the state following the end of the fuel cut state, the response delay of the sensor is large, so the table value is used instead of the actual measured value during that time. In addition, the flag register indicates that the engine speed is 200Or
If a situation such as exceeding pm occurs, it will be turned off (3226).
Therefore, from then on, the judgment in 8218 will also be denied and the control value will be calculated based on the actual measured value (in addition, if fuel cut control is performed, the micro-
This information will be stored in an appropriate location in the computer's RAM 50f, etc.). Remaining step 52
10, 220 to 224, and 228 to 230 are the same as in the first embodiment.

In addition to the advantages of the first operation example, this operation example has the advantage of being able to more accurately respond to changes in the operating state when sudden acceleration is made from the fuel cut state.

In the above explanation, the fuel injection amount and ignition timing are exemplified as control values, but the invention is not limited to these, and can be applied to any device that uses intake pressure as a control parameter. It is something.

(Effects of the Invention) The control device for an internal combustion engine according to the present invention includes an intake pressure setting means for setting the intake pressure determined from the throttle valve opening when the speed of change of the throttle valve is equal to or higher than the predetermined speed of change at a predetermined rotation speed or less. Since the control value determining means is configured to determine the control value based on the set value when the intake pressure setting means sets the intake pressure, it is no longer necessary to correct the detection delay of the sensor. This simplifies the calculation of control values and does not cause delays in the control system, improving control responsiveness and drivability during transients, and reducing knocking that tends to occur during transients. It has the advantage of being able to quickly avoid any collisions. Furthermore, when a microcomputer is used for calculations, it has the advantage that its memory capacity can be reduced and manufacturing costs can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a claim correspondence diagram of a control device for an internal combustion engine according to the present invention, FIG. 2 is an explanatory block diagram showing the overall configuration of the device, FIG. 3 is a flow chart showing an example of the operation of the device, and FIG. The figure is an explanatory graph showing the intake pressure table values used for calculation in this operation, and FIG. 5 is a flow chart showing another example of the operation of this apparatus. 10... Engine rotation speed detection means (crank angle sensor 58
), Work 2... Intake pressure detection means (pressure sensor 36),
14... Control value determining means (microcomputer 5
0), 16... actuator means (distributor 54. first output circuit 66, spark plug 689. second
Output circuit 7o, fuel injection device 72. Injection valve 74), 18
...Throttle valve opening detection means (throttle sensor 3
8), 19... Intake pressure setting means (micro computer 50), 20... Internal combustion engine, 26... Throttle valve, 46... Control unit, 50... Micro computer 18=

Claims (2)

[Claims] (1): (a) An engine rotation speed detection means arranged near the rotating part of the internal combustion engine to detect the engine rotation speed; b. An engine rotation speed detection means arranged at an appropriate position in the intake passage of the internal combustion engine to detect the air intake into the engine. intake pressure detection means for detecting pressure; c. control value determination means for determining a control value for engine operation by inputting the outputs of the engine speed detection means and the intake pressure detection means; and d. the control value determination means. An internal combustion engine control device comprising: actuator means for engine operation operated by inputting an output; e. Throttle valve opening detection means for detecting the opening of a throttle valve disposed in the engine intake passage; f. The outputs of the throttle valve opening detection means and the engine speed detection means are input, and the rate of change of the throttle valve is calculated from the output of the throttle valve opening detection means, and the calculated value is less than or equal to a predetermined rotation speed and the speed of change is a predetermined value. Intake pressure setting means for setting the intake pressure determined from the throttle valve opening in the above cases, and when the intake pressure setting means sets the intake pressure, the control value determining means determines the intake pressure based on the set value. 1. A control device for an internal combustion engine, characterized in that the control device is configured to determine a control value based on the control value. (2) The control device for an internal combustion engine according to claim 1, wherein the control value is a fuel injection amount or ignition timing.