JPS63223340A - Intake air quantity control device for engine - Google Patents

Abstract

PURPOSE:To enable a required intake air quantity to be secured at the time of deceleration, in an engine in which dashpot control is carried out by supplying auxiliary air, by providing a means by which the reduction in the initial valve of dashpot control up to the starting time of dashpot control is lessened after the full-closing of a throttle valve. CONSTITUTION:On the basis of the output signals from an airflow sensor 6 and a crank angle sensor 11, a control unit 9 calculates the charging efficiency representing an engine load by means of a calculating means A, and on the basis of this charging efficiency and the engine speed the basic initial value of dashpot control is calculated by means of a calculating means B. Next, when the full-closing of a throttle valve 7 is judged by means of a calculating means C from the output of an airflow sensor 6, a correction is added to the basic initial value; when it is not so, the basic initial value is outputted to a calculating means D as it is as the initial value of dashpot control. And, after the throttle valve 7 has been fully closed, when a soft switch SW is turned ON after the lapse of a prescribed time, a dashpot control starting signal is outputted to operate a control valve 10 inside an auxiliary air passage 8 which bypasses the throttle valve 7.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an engine intake air amount control device, and more particularly to an engine intake air amount control device based on dashpot control.

Prior Art Generally, in engines equipped with fuel injection nozzles,
An air flow sensor detects the intake air flow rate supplied to the engine according to the driver's accelerator pedal operation, and based on this output, controls the opening time of the fuel injection nozzle to inject fuel commensurate with the air flow rate. is configured to do so. However, when controlling the fuel injection amount based on the air flow rate determined in conjunction with the driver's accelerator pedal operation, the intake negative pressure downstream of the throttle valve becomes too high during deceleration. If there is an excess of fuel supplied, or the frictional torque of the engine is large at the time of starting, it is necessary to increase the amount of intake air as well as the amount of fuel, or when operating the air conditioner during idling, the temperature or pressure may Since there is a problem in which the idle speed fluctuates when the engine speed changes, the upstream and downstream sides of the throttle valve are connected directly to each other in order to replenish and control the amount of intake air independently of the driver's accelerator pedal operation. An auxiliary air passage and a valve that can change the cross-sectional area of the auxiliary air passage are provided, and the opening degree of the valve provided in the auxiliary air passage is controlled according to the engine operating condition. 2. Description of the Related Art An engine intake air amount control device that controls the flow rate of air passing through an air passage is known. (Unexamined Japanese Patent Publication No. 55-69
739 etc. ) Also, when the driver operates the accelerator pedal to close the throttle valve during deceleration, it prevents sudden changes in the intake air and removes harmful components from the exhaust gas. A mechanical means that performs so-called dashpot control, in which the throttle valve is controlled to gradually close immediately before it is fully opened, to gradually reduce the amount of intake air to the idle operating state, in order to reduce the amount of intake air and reduce the shock. An engine intake air amount control device having the following is also known.

This type of dashpot control does not require any special mechanical means, but by providing the above-mentioned auxiliary air passage with a valve inside it that controls the amount of intake air, the valve opens when the throttle valve is closed. control the degree,
This can also be realized by supplying auxiliary air from an auxiliary air passage so that the amount of intake air gradually changes, and an engine intake air amount control device configured in this manner is also known. There is.

In this way, by supplying auxiliary air from the auxiliary air passage, in order to control the intake air amount in the same way as when controlling the dashpot by mechanical means,
Amount of auxiliary air at the time of starting dashpot control,
That is, it is necessary to determine the initial value to correspond to the amount of intake air at the time when the throttle valve in a device using conventional mechanical means starts to gradually close. In general, the required amount of intake air is determined by the engine speed or load and is determined experimentally in advance as a function of engine speed and engine load, in the form of a map.
The initial value for dashpot control is also calculated from this map based on the engine speed and load at each point in time, and is stored in the control unit. Dashpot control was generally configured to perform dashpot control based on initial values stored in the unit.

Additionally, when performing dashpot control by supplying auxiliary air from the auxiliary air passage, it is necessary to detect the fully closed throttle valve and control the supply of auxiliary air from the auxiliary air passage. However, the mechanical switches normally used to detect the opening and closing of the throttle valve tend to malfunction due to chuckling, so as soon as the mechanical switch detects that the throttle valve is fully closed, it immediately removes the air from the auxiliary air passage. Starting the auxiliary air supply can sometimes result in inhalation of an inadequate amount of air, so the auxiliary air passage is then activated only when the mechanical switch continues to detect the throttle valve fully open for a certain period of time. It is necessary to control the supply of auxiliary air to start. therefore,
After the mechanical switch detects that the throttle valve is fully closed, dashpot control is now started only when the control unit's soft switch is turned on, which is configured to turn on when the fully open detection signal continues for a certain period of time. An intake air amount control device for an engine has been developed.

Problems to be Solved by the Invention However, when the mechanical switch is configured to start dashpot control only when the soft switch of the control unit is turned on after detecting that the throttle valve is fully open, If the throttle valve is truly fully closed when the mechanical switch detects that the throttle valve is fully open, the engine load will drop by the time the soft switch is turned on, and the moment when dashpot control actually starts. If the initial value is calculated using a pre-stored map based on the engine load, the initial value will be smaller than the desired initial value, and only a smaller amount of air can be taken in than the required intake air amount. During deceleration, it was not possible to control the amount of intake air as desired.

Purpose of the Invention The present invention is an engine intake air amount control device that performs dashpot control by supplying auxiliary air from an auxiliary air passage. It is an object of the present invention to provide an engine intake air amount control device that can be controlled as desired.

SUMMARY OF THE INVENTION An object of the present invention is to control the dashpot control so that the decrease in the initial value of the dashpot control due to the fully closing of the throttle valve is small until the soft switch is activated after the throttle valve is fully closed. This is achieved by providing a control unit with means for calculating the initial value of .

EXAMPLES Hereinafter, examples of the present invention will be described in detail based on the accompanying drawings.

FIG. 1 is a schematic diagram of an engine including an engine intake air amount control device according to an embodiment of the present invention, and FIG. 2 is a block diagram of the engine intake air amount control device according to an embodiment of the present invention. It is.

In FIG. 1, an engine 3 equipped with a piston 2 that reciprocates within a cylinder bore 1 is connected to an intake passage 4 and an exhaust passage 5, respectively. An air flow sensor 6 is provided upstream of the intake passage 4, and a throttle valve 7 is provided within the intake passage 4 downstream thereof.

The upstream and downstream sides of the throttle valve 7 are directly connected to each other by an auxiliary air passage 8, and the passage cross-sectional area of the auxiliary air passage 8 is controlled by an output signal from a control unit 9. A control valve 10 is provided to control the. The control unit 9 includes an intake air amount detection signal from the airflow sensor 6, a throttle distance detection signal from the opening detection means (not shown) of the throttle valve 7, an engine rotation speed detection signal from the crank angle sensor 11, and A load detection signal from a load detection means 12 for detecting loads such as , power steering, near conditioner, and D range is manually input. The control unit 9 has a setting (1) for the opening degree of the control valve 10 provided in the auxiliary air passage 8 which is experimentally determined in advance as a function of the engine speed and the engine load and is stored in the form of a map. The control unit 9 calculates a desired value of the opening degree of the control valve 10 based on the input signal, and sends a signal for controlling the opening degree of the control valve 10 to a control valve driving means (not shown).
is configured to output to .

In FIG. 2, the intake air amount detection signal from the air flow sensor 6 and the engine rotation speed detection signal from the crank angle sensor 1 are input manually to the charging efficiency calculation means of the control unit 9, and the charging efficiency representing the engine load is calculated. Ru. The filling efficiency calculation means outputs the calculation result to the dashpot control basic initial value calculation means. On the other hand, the engine rotation speed detection signal from the crank angle sensor 11 is also
It is output to the dashpot control basic initial value calculation means.

In the dashpot control basic initial value calculation means, basic initial values for the dashpot control are determined experimentally in advance as a function of engine speed and load and are stored in the form of a map. The basic initial value calculation means calculates the dashpot control basic initial value based on these human input signals and this map,
Output to dashpot control initial value calculation means. The dashpot control initial value calculation means includes an air flow meter 6.
If the intake air amount detection signal is manually input, and it is determined from the intake air amount detection signal that the intake air amount has decreased and the throttle valve is fully closed, the dashpot control basic initial value that was manually input is determined. If not, the human-operated dashpot control basic initial value is directly output to the control valve opening calculation means as the dashpot control initial value. The control valve opening calculation means calculates the opening of the control valve at the time of starting the dashpot control based on the manually inputted dashpot control initial value signal.

On the other hand, if the mechanical switch remains on for a certain period of time after the mechanical switch is turned on, the soft switch that turns on will output a dashpot control start signal from the soft switch to the control valve opening calculation means. The control valve opening calculation means calculates and outputs the held control valve opening control signal at the start of dashpot control to the control valve driving means, and the control valve driving means operates based on this signal. to set the opening degree of the control valve.

FIG. 3 shows the dashpot control initial value Q1 in the intake air amount control device of this embodiment. ．． It shows a flowchart of calculations.

The intake air amount detection signal from the air flow sensor 6, the throttle opening detection signal from the opening detection means of the throttle valve 7, the engine rotation speed detection signal from the crank angle sensor 11, and the power steering, near conditioner, D range, etc. A load detection signal from the load detection means 12 that detects the load is read. Next, the charging efficiency is calculated, and the dashpot control basic initial value Q is determined based on the stored map based on the calculated charging efficiency and engine speed. My calculations are calculated.

When it is determined from the intake air amount detection signal inputted from the air flow make 6 that the throttle valve is fully closed, the dashpot control initial value calculation means calculates the dashpot control initial value Q calculated last time. −1 and the dashpot control basic control value Q manually inputted this time by the dashpot control basic initial value calculating means. The difference from 0 is calculated and compared with a predetermined unit decrease value ΔQ. The difference is the unit decrease value △
When the difference is larger than Q, it is set as Q i n ”Q i , -1 - △Q, and when the difference is not larger than the unit decrease value △Q, it is set as Q, □ = Qoh, and the control valve opening calculation means is set. Output.This operation is repeated below.

When the dashpot control start signal is input from the soft switch, the control valve opening calculation means outputs the control valve opening control signal calculated at that time to the control valve driving means, and drives the control valve. The means sets the opening degree of the control valve based on this signal.

In this way, in this embodiment, the throttle valve 7
After detecting full opening, the amount of decrease in the initial value of dashpot control exceeds the unit decrease value ΔQ, regardless of the basic control value of dashpot control determined from the map, according to the engine speed and load at each point in time. However, even if the dashpot control basic control value at that point is adopted, only if the difference from the previous dashpot control initial value is equal to or smaller than the unit decrease value ΔQ, The dashpot control basic control value determined from the map based on the engine speed and load is output to the control valve opening calculation means as the dashpot control initial value, so when the throttle valve 7 is fully opened, the load is It is possible to reduce an undesirable drop in the initial value at the start of dashpot control due to a sudden drop in
It becomes possible to minimize the shortage of intake air amount in dashpot control.

FIG. 4 is a graph schematically showing changes in the dashpot control initial value calculated according to this embodiment.

In FIG. 4, line A is the throttle valve opening, line B is the engine load, line C is the initial value of the dashpot control calculated in this example, and the line is the engine rotational speed at each point in time. and the basic initial value of the dashpot control calculated based on the load (that is, the value calculated from the map). In Figure 4,
The throttle valve begins to close at time t2 and becomes fully closed at time t2. When the throttle valve begins to close, the engine load begins to decrease, and accordingly, the dashpot control initial value also begins to decrease. After the throttle valve is fully closed, the soft switch is turned on at time t3 and dashpot control is started, but by then the engine load has significantly decreased, although there is some time delay. Therefore, the dashpot control basic initial value calculated based on the engine speed and load at each point in time also decreases significantly, so when performing dashpot control based on this basic initial value, the intake air amount is insufficient. Resulting in. In this embodiment, as shown by line C, the dashpot control is controlled so that the initial value of the dashpot control does not decrease with the engine load between time t2 when the throttle valve is fully opened and time t3. Since the dashpot control initial value is calculated and output by adding the above-mentioned correction to the basic initial value, it is possible to minimize the shortage of intake air amount. In FIG. 4, the line C decreases stepwise after time t3 because
Indicates that dashpot control is being performed.

The present invention is not limited to the above-mentioned examples, but various modifications can be made within the scope of the invention described in the claims, and these are also included within the scope of the present invention. Needless to say.

For example, in the embodiment, the throttle valve 7
After fully closing, the dashpot control initial value calculated does not decrease as the engine load decreases, and the amount of decrease in the initial value in one calculation cycle is controlled to be less than or equal to the unit decrease value. However, it is not limited to this calculation method. For example, instead of this, dashpot control can be performed by calculations such as Q, , = α・Q+−+ + (1−α)QIh. The initial value may be prevented from decreasing with engine load, and other calculation methods may also be used.

In addition, in the above embodiment, the dashpot control initial value is calculated by adding correction to the dashbot control basic initial value calculated based on the engine speed and load at each time point. The dashpot control initial value is calculated using a map based on the value of the engine load detected by the above-mentioned correction, and the amount of decrease is smaller than the actual engine load. In this case, the dashpot control initial value calculated from the map is output as is to the control valve opening calculation means.

Further, in the embodiment described above, the air flow sensor 6 detects the fully closing of the throttle valve 7, and the dashpot control initial value calculation means starts control to reduce the decrease in the initial value of the dashpot control. The dashpot control initial value calculation means may be operated at all times, and in the case of deceleration, control may be performed to reduce the decrease in the initial value of the dashpot control in the same manner as described above.

Furthermore, in the embodiment described above, the dashpot control basic initial value is determined as a function of the engine rotation speed and the load, but it may be determined as a function of the engine rotation speed or the load.

Further, in the embodiment described above, only the control means is provided so as not to gradually reduce the intake air amount when the throttle valve is fully closed, but furthermore, when the throttle valve changes from fully closed to fully open, A control means for gradually increasing the amount of intake air may be configured and provided in the same manner as the control means for gradually reducing the amount of intake air in the above embodiment.

Effects of the Invention According to the present invention, it is possible to prevent an undesirable decrease in the initial value of the dashpot control after the throttle valve is fully closed until the start of the dashpot control, and to prevent an insufficient intake air amount during the dashpot control. can be minimized.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of an engine including an engine intake air amount control device according to an embodiment of the present invention, and FIG. 2 is a block diagram of the engine intake air amount control device according to an embodiment of the present invention. It is. FIG. 3 shows a dashpot control initial value Q of an engine intake air amount control device according to an embodiment of the present invention.
It is a flowchart of +h operation. FIG. 4 is a graph schematically showing changes in the dashpot control initial value calculated according to an embodiment of the present invention. 1... Cylinder bore, 2... Piston, 3...
...Engine, 4...Intake passage, 5...Exhaust passage, 6...Air flow sensor, 7...Throttle valve, 8...Auxiliary air passage, 91...Control unit, 10... Control valve, 11... Crank angle sensor, 12... Load detection means.

Claims (1)

[Claims] An auxiliary air passage that connects the upstream and downstream sides of the throttle valve so that they can communicate directly, a control valve provided in the auxiliary air passage, and a control valve that opens based on engine speed and/or engine load. The control unit outputs a degree control signal, and includes a soft switch that is turned on after a predetermined time has elapsed after the throttle valve is fully closed, and when the soft switch is turned on, dashpot control of the control valve opening is performed. and a control unit for controlling the intake air amount of an engine, wherein the control unit controls, at least after the throttle valve is fully closed, until the soft switch is turned on, the dashpot that accompanies the fully closing of the throttle valve. An intake air amount control device for an engine, comprising means for calculating an initial value of the dashpot control so that a decrease in the initial value of the control is small.