JPH0245008B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for controlling an air pump for supercharging an internal combustion engine, and in particular, the present invention relates to a method for controlling an air pump for supercharging an internal combustion engine, and in particular, the Q/N calculated based on air pump operation determination conditions (where Q is the intake air amount of the engine,
The present invention relates to a supercharging air pump control method for an internal combustion engine, characterized in that N is the engine rotational speed).

When Q/N is used as one of the air pump working conditions, conventionally, the current Q/N calculated at the calculation cycle of an electronic control device such as a microcomputer or minicomputer is used, and the air pump operation condition whose value is determined is used. The air pump was operating when the threshold value was exceeded. However, it is generally known that immediately after acceleration, a Q/N overshoot phenomenon occurs due to an overshoot of the air flow meter that detects the amount of engine intake air. This phenomenon may cause the air pump to operate temporarily at the beginning of acceleration. There is no need for temporary air pump operation due to such a Q/N overshoot, and it is expected that drivability during acceleration will deteriorate as a result.

In view of the above problems, when using Q/N as one of the operating conditions of an air pump, the present invention does not use the Q/N calculated at each moment by an electronic control device, but uses a rounded Q/N. By using /N, the problem of the air pump being temporarily activated due to Q/N overshoot at the beginning of acceleration is eliminated, and good drivability can be obtained by controlling the air pump for supercharging of an internal combustion engine. The purpose is to provide a method.

The present invention will be explained below according to an embodiment shown in the drawings. FIG. 1 is a block diagram of an embodiment of the present invention. 1 is a multi-cylinder internal combustion engine, 2 is a surge tank connected to intake pipes 13 and 14 branched on the upstream side of the throttle valve, and 3 is a distributor housing a rotation sensor that detects the rotational speed of the internal combustion engine. , has the function of distributing ignition energy to each cylinder. 4 is an air cleaner; 5 is an air flow meter installed in the intake pipe 12 on the upstream side of the throttle valve; 6 is the throttle valve; 7 is a supercharging control valve installed in one of the branched intake pipes 13. , 8 is a supercharging air pump for the internal combustion engine 1 installed in one of the branched intake pipes 14, 9 is a magnetic clutch for driving the air pump 8, and 10
is an electronic control device which receives the rotation signal N from the distributor 3 and the intake air amount signal Q from the air flow meter 5 and calculates Q/ as a value corresponding to the engine load amount.
N is calculated, and when the air pump operating conditions are satisfied, the supercharging control valve 7 is closed, and at the same time, the magnetic clutch 9 is connected and operated by a control signal from the control device 10 to operate the air pump 8. Also 15
An injector for injecting fuel into the engine 1 is controlled by a control signal from the control device 10. 16 and 17 are pulleys, 18 is a belt, and the engine 1 is configured to be used as a power source for the air pump 8.

In operation, when the engine load is on the light load side, the air pump 8 is stopped and the supercharging control valve 7 is fully open, so that the air sucked through the throttle valve 6 is substantially absorbed into the intake pipe 13. It enters the surge tank 2 through the pump and is supplied to the engine 1.
On the other hand, when the engine load exceeds the set value,
Since the supercharging control valve 7 is closed and the air pump 8 is operated at the same time, the air taken in through the throttle valve 6 is supercharged through the intake pipe 14 and is supplied to the engine 1 through the surge tank 2.

Note that in this embodiment, the air pump 8 is arranged downstream of the throttle valve 6;
The present invention can also be achieved by arranging the air pump 8 on the upstream side of the air pump 8.

FIG. 2 shows an example of a control program for implementing the present invention. In this embodiment, the electronic control device 10 shown in FIG. 1 is intended to determine the fuel injection amount and the operation of the air pump 8.
Although the former calculation is not shown, the calculation is started by issuing an interrupt command to the computer in accordance with the crank angle position of the internal combustion engine 1. The calculated amount of fuel is then injected from the injector 15 at a predetermined crank angle. Also, the latter calculation is generally initiated by a timer interrupt. Therefore,
In step 101 in FIG. 2, each data of the engine intake air amount Q, the engine rotational speed N, the engine temperature T (for example, the cooling water temperature), and other engine parameters are read. In step 102, Q/N is calculated, and in step 103, a smoothing calculation of Q/N is executed. An example of Q/N rounding calculation is shown below. This is a method of taking the average value of the data Q/N of two times before and after. Of course, it is easily possible to employ other known annealing processes.

Q/N={(Q/N)i+(Q/N)i-1}/
2 However, (Q/N)i is the current calculated value (Q/N)i-1 is the previous calculated value (e.g.
(Value 8 ms ago) Next, in step 104, a determination value K of Q/N is determined. This judgment value K is the engine state (N, Q/
A predetermined value is read from a map that is set in advance according to the value N). This judgment value K is
It is determined so as to obtain the desired engine output characteristics by taking into consideration engine-specific output characteristics, air pump characteristics, engine required output under various operating conditions, etc.

In steps 105, 106, and 107, the operating conditions for the air pump 8 are that the engine temperature T is higher than the set value T0 indicating warm-up, the engine rotational speed N is higher than the set value N0, and Q/N is larger than the judgment value K. For the first time, the program proceeds to step 108 and issues an air pump operation command. As a result, the supercharging control valve 7 closes and the magnetic clutch 9 is connected, the air pump 8 is driven by the engine, and supercharged intake air is sent into the engine. On the other hand, step 105
If any one of the conditions is not satisfied in steps 107 to 107, the process proceeds to step 109 and an air pump operation stop command is issued. Therefore, in this case, the supercharging control valve 7 is opened and the magnetic clutch 9 is released. As a result, the air that has passed through the throttle valve 6 is directly sent to the engine via the supercharging control valve 7. Thereafter, this control program will be repeated at predetermined intervals (for example, 8 ms).

Figure 3 shows the Q/N-T curve during engine acceleration, with Q/N plotted on the vertical axis against time t on the horizontal axis.
It shows the change in Q/N over time during acceleration.
Q/N during acceleration moves as shown in solid line A,
There is an overshoot phenomenon at the beginning of acceleration. Due to this overshoot phenomenon, Q/N becomes larger than the air pump operation determination value K at the beginning of acceleration, and the air pump enters the supercharging region and temporarily operates. Therefore,
As shown in step 103 of Fig. 2, the Q/N is rounded and calculated, and the movement is made as shown by the broken line B in Fig. 3, thereby inhibiting air pump operation due to overshoot and improving the driving feeling. There is.

In addition to the above method, the engine intake air amount Q obtained from the air flow meter 5 as the engine load amount can also be used.
There is also a method of smoothing the signal. Also, Q/
Instead of N, the basic injection pulse width (=α・Q/N, α
may be used as the air pump operation determination condition.

As described above, the method of controlling an air pump for supercharging of an internal combustion engine according to the present invention uses an engine load calculated according to one of the air pump operating conditions to prevent overshoot of the initial engine load during acceleration. This feature is characterized by prohibiting air pump operation, which has the advantage that unnecessary air pump operation is prohibited and even better drivability can be obtained.

In addition, a predetermined value is read from a map that is preset according to the engine condition, and this read value is used as a predetermined value and compared with a value that smoothes the engine load. Not only can the desired engine output be obtained by considering the characteristics of the engine or the required engine output under various operating conditions, but even if the predetermined value changes depending on the engine condition, the On the other hand, it has the advantage that it can be dealt with very easily simply by determining whether or not the value obtained by rounding down the engine load exceeds a predetermined value.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram of an apparatus showing an embodiment of the present invention, FIG. 2 is a flowchart showing an example of a control program for realizing the present invention, and FIG. 3 is a characteristic diagram for explaining the present invention. . 1... Internal combustion engine, 2... Surge tank, 5... Air flow meter, 6... Throttle valve, 7... Supercharging control valve,
8...Air pump, 9...Magnetic clutch, 10
…Electronic control device.

Claims (1)

[Scope of Claims] 1. A supercharging system in which a supercharging air pump is disposed in the intake pipe of an internal combustion engine, and when the engine load exceeds a predetermined value, the air pump is activated to supply supercharged air to the engine. This is an air pump control method, in which a predetermined value is read from a map that is preset according to the engine condition, the engine load is determined at a predetermined time or every predetermined crank angle, and this engine load is subjected to smoothing processing. . A method for controlling an air pump for supercharging an internal combustion engine, characterized in that the air pump is operated when a value subjected to the smoothing process exceeds a predetermined value read from the map. 2. A supercharging air pump control method for an internal combustion engine according to claim 1, wherein a ratio Q/N of an intake air amount Q to an engine speed N is used as the engine load amount.