JPH0444094B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention electrically controls the amount of fuel supplied to an internal combustion engine, in which data for determining the amount of fuel supplied to the internal combustion engine is determined based on the intake pipe pressure and rotational speed of the internal combustion engine. The present invention relates to a fuel control device for an internal combustion engine that controls a fuel supply amount based on data stored in a memory in advance for each operating state determined by the operating state and read out in response to each operating state.

When electrically controlling the amount of fuel supplied to an internal combustion engine, it is necessary to detect the amount of intake air of the internal combustion engine and supply fuel at a predetermined ratio to this amount of intake air.

As a method of detecting the intake air amount of an internal combustion engine,
There is a method of calculating the amount of intake air from the intake pipe pressure and rotational speed of the internal combustion engine.

In this case, if a method is used to recirculate part of the exhaust gas to the intake side (hereinafter referred to as EGR) as one of the exhaust gas countermeasures, the internal combustion engine will be able to suck in not only fresh air but also exhaust gas at the same time. become. Since this exhaust gas does not participate in combustion, it is necessary to supply fuel at a predetermined ratio to the intake air amount of fresh air, which is obtained by subtracting the above exhaust gas amount from the intake air amount of the internal combustion engine. However, when calculating the amount of intake air using the intake pipe pressure and rotational speed as described above, the amount of exhaust gas from the EGR is also included in the calculation. In order to calculate the fresh intake air amount described above, a method can be considered in which the above EGR exhaust gas amount is calculated and removed from the intake air amount calculated from the intake pipe pressure and rotational speed. For example, the amount of exhaust gas from EGR is calculated from the amount of movement of an EGR valve that controls the amount of exhaust gas from EGR.

However, since the amount of EGR exhaust gas also depends on the differential pressure applied to the EGR valve, it is difficult to accurately calculate the amount of EGR exhaust gas. There is a problem in that it is difficult to adjust to the desired air-fuel ratio and cannot accurately control the desired air-fuel ratio.

The present invention was made to solve the above-mentioned drawbacks, and stores data for determining the fuel supply amount when EGR is not applied to the internal combustion engine in correspondence with the intake pipe pressure and rotation speed of the internal combustion engine. Furthermore, data for determining the fuel supply amount when EGR is applied to the internal combustion engine is stored in the memory table corresponding to the intake pipe pressure and rotation speed of the internal combustion engine, and the EGR valve of the internal combustion engine is stored in the memory table. By selecting the above two types of tables corresponding to the opening/closing state of the engine and controlling the fuel supply amount of the internal combustion engine based on the data of the selected table, even when EGR is applied, the predetermined air-fuel ratio can be maintained accurately. The purpose is to provide a device that can be controlled.

The present invention will be described below with reference to an embodiment shown in the drawings.

FIG. 1 is a diagram showing the configuration of an embodiment of the present invention.
The internal combustion engine 101 is a known four-stroke spark ignition internal combustion engine mounted on an automobile, and intakes combustion air through an air cleaner 102, an intake pipe 103, and a throttle valve 104. Further, fuel is supplied to the throttle valve 1 of the intake pipe 103 from a fuel system (not shown).
The fuel is supplied through an electromagnetic injection valve 105 provided upstream of the fuel injection valve 04. A pressure sensor 106 is provided downstream of the throttle valve in the intake pipe 103 to detect the absolute pressure in the intake pipe 103 and convert it into a voltage. The ignition coil 107 supplies high voltage to a spark plug (not shown) provided for each cylinder of the internal combustion engine 101 .

The fuel control device 108 receives output signals from the pressure sensor 106, the ignition coil 107, etc., and drives the electromagnetic injection valve 105.

A part of the exhaust gas branched to the exhaust branch pipe 109 connected to the exhaust pipe 115 is transferred to the EGR valve 110.
The throttle valve 104 of the intake pipe 103
It is returned to the internal combustion engine 101 through an EGR introduction pipe 111 connected to the downstream side of the engine.

A position sensor 113 that detects the position of the EGR valve and converts it into voltage is connected to the EGR valve 110.

The EGR control device 114 includes a pressure sensor 106,
The force motor 112 is driven by inputting the output signals of the ignition coil 107, the position sensor 113, etc.
The EGR valve 1
Negative feedback control is performed to match the positions of 10.

FIG. 2 is a diagram showing the configuration of the EGR control device 114, in which the EGR calculator 201 sends the output of the pressure sensor 106 and the primary side signal of the ignition coil 107 to the comparator 20.
2, the signal waveform-shaped and converted to a logic level, the output of the position sensor 113, etc. are input, and the intake pipe 106
predetermined by the pressure and rotation speed of
A control amount corresponding to the deviation between the target position and the position of the EGR valve 110 is added to a control amount corresponding to the target position of the EGR valve 110, and a control signal corresponding to this corrected control amount is output to the driver 203. do. The driver 203 is the EGR calculator 20
1, the drive current of the force motor 112 is controlled, and the opening of the EGR valve 110 is controlled to match the target position. The comparator 204 is
If the output of the position sensor 113 is above a predetermined value, it outputs "H", and if it is less than the predetermined value, it outputs "L".

FIG. 3 is a diagram showing the configuration of the fuel control device 108, in which the pulse width calculator 301 is connected to the pressure sensor 106.
A numerical value obtained by converting the output of
The numerical value converted by the A/D converter 305 and the output signal of the comparator 204 of the EGR control device 114 are input to the internal combustion engine 101.
The driving time of the electromagnetic injection valve 105 is calculated according to the operating state of the electromagnetic injection valve 105. The timer 307 is the oscillator 306
When the trigger signal is output from the comparator 303 in synchronization with the engine ignition timing, with
The output of this timer 307 is set to "H", a numerical value output from the pulse width calculator 301 is set in an internally provided down counter (not shown), and the oscillator 30
The value set in the down counter is counted down every six output pulses, and when it reaches zero, the output of this timer is set to "L". The driver 308 is
The electromagnetic injection valve 105 is driven only while the output of the timer 307 is "H".

FIG. 4 shows a configuration diagram of the pulse width calculator 301, and the function generator 401 includes an EGR valve 110.
Fuel that corresponds to a plurality of operating states of the engine that are two-dimensionally classified depending on the pressure and rotational speed of the intake pipe 103 of the internal combustion engine 101 when the engine is opened less than a predetermined value (hereinafter referred to as EGR off). The supply amount, that is, the numerical value that determines the driving time of the electromagnetic injection valve 105 is stored in the built-in read-only memory in the form of a table, and the correspondence stored in the read-only memory by the output of the A/D converters 302 and 305 is stored in the built-in read-only memory in the form of a table. The data to be selected is selected and output to the data selector 403.

The function generator 402 indicates that the EGR valve 110 is open by a predetermined value or more (hereinafter referred to as EGR ON).
The amount of fuel supplied, that is, the driving time of the electromagnetic injection valve 105, is determined in accordance with a plurality of operating states of the engine, which are two-dimensionally divided according to the pressure and rotational speed of the intake pipe 103 of the internal combustion engine 101. The numerical values are stored in a built-in read-only memory in the form of a table, and similar to the function generator 401, the A/D converter 302,
Based on the output of 305, the corresponding data stored in the read-only memory is selected and output to data selector 403. Data selector 403
is the output of the function generator 402 when the output signal of the comparator 204 of the EGR control device 114 is "H", that is, EGR is on, and the output of the function generator 401 when it is "L", that is, EGR is off. is output to the timer 307.

Here, when the output of the comparator 204 is "L", that is, when the EGR of the internal combustion engine 101 is off, the driving time of the electromagnetic injection valve 105 is determined based on the data output from the function generator 401, When the output of the internal combustion engine 101 is "H", that is, the EGR of the internal combustion engine
When it is on, the driving time of the electromagnetic injection valve 105 is determined by the data output from the function generator 402.

Here, the data stored in the function generators 401 and 402 is not a value that directly corresponds to the drive time of the injection valve 105, but only the correction data for correcting the suction pressure detection information, and this data is used to correct the suction pressure detection information. By correcting the pressure detection information, the injection valve 10
If a value corresponding to the driving time of 5 is calculated, highly accurate control is possible while reducing the memory capacity of the function generators 401 and 402.

This will be explained based on FIG. FIG. 5 shows an example of a pulse width calculator used in the present invention.

When storing the fuel injection amount itself, the driving time of the injector (fuel injection amount) that supplies fuel injection is usually determined based on the intake pipe pressure when the internal combustion engine is warm.
While it varies between 200mmHg and 760mmHg.
A time of about 2500μsec to 12000μsec is required.
Therefore, if you store the numbers 2500 to 12000 in the function generator as they are, the
2Byte (16bit) is required. On the other hand, in the method of storing correction data in the function generator as shown in FIG. 5, the value of the correction data may have a resolution on the order of %, so it may be a numerical value of around 100. Therefore, in order to store one correction data, 1 byte is sufficient, so only 1/2 of the storage capacity is required compared to storing the fuel injection amount itself. That is, the coefficient corresponding to the filling efficiency at the intake pipe pressure and rotational speed of the internal combustion engine 101 when EGR is off is calculated based on the intake pipe 10
Function generator B stored in the built-in read-only memory in the form of a table corresponding to the pressure and rotation speed of 3.
Then, a coefficient corresponding to the ratio of the intake air amount of the internal combustion engine 101 when EGR is on and the intake air amount when EGR is off is written in a built-in read-only function corresponding to the pressure and rotation speed of the intake pipe 103. A function generator C stored in the memory in the form of a table is provided, and when EGR is off, function generator B is selected and the output of this function generator B and the output of the A/D converter 302 (intake negative The drive time of the electromagnetic injection valve 105 is determined by multiplying the pressure information), and when EGR is on, both function generators B and C are selected, and the Output and A/D converter 30
The driving time of the electromagnetic injection valve 105 may be determined by multiplying the output of the function generator C and the output of the function generator C, respectively.

In addition, coefficients corresponding to the filling efficiency when EGR is on and off are stored in function generators D and E in the form of tables, respectively, and coefficients are stored in function generators D and E corresponding to EGR on and off. The drive time of the electromagnetic injection valve 105 may be determined by selectively selecting one of the above and multiplying the output of the A/D converter 302 by the above coefficient.

As described above, according to the present invention, the first data determines the fuel supply amount to the internal combustion engine when EGR is off, and the first data determines the fuel supply amount to the internal combustion engine when EGR is on. 2 data are stored in the memory, the above two data types are selected depending on the EGR status, and the fuel supply amount is determined based on the selected data. Even when EGR is on, the predetermined air-fuel ratio is accurately set. There are effects that can be controlled. Also, when EGR is off,
The data that determines the fuel supply amount corresponding to each case is set corresponding to each operating state of a plurality of internal combustion engines, which is determined two-dimensionally by the engine's intake pipe negative pressure and rotation speed. Since it is stored in memory, it is possible to change between each operating state when EGR is on.
Even if the EGR amount fluctuates, the fuel supply amount can be set by matching the EGR amount in each operating state, so the fuel supply amount can be set in the desired relationship with the fresh air intake amount regardless of the EGR amount fluctuation. This has the effect of allowing accurate air-fuel ratio control. In addition, the first and second data stored in the memory are correction value data for correcting the intake pressure detection information of the engine, and the intake pressure detection information is corrected by this read data. Since the amount of fuel supplied from the fuel injection valve is calculated by doing this, it is possible to calculate the amount of fuel supplied with high accuracy while reducing the capacity of the memory that stores the first and second data.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing one embodiment of the present invention, and FIG.
3 is a configuration diagram of the EGR control device 114 in FIG. 1, FIG. 3 is a configuration diagram of the fuel control device 108 in FIG. 1, and FIG. 4 is a configuration diagram of the pulse width calculator 301 in FIG. 3.
FIG. 5 is a schematic configuration diagram showing one embodiment of the pulse width calculator 301. 101... Internal combustion engine, 102... Air cleaner, 103... Intake pipe, 104... Throttle valve, 105... Electromagnetic injection valve, 106... Pressure sensor, 107... Ignition coil, 108... Fuel control device , 109... Exhaust branch pipe, 110...
EGR valve, 111...EGR introduction pipe, 112...
... force motor, 113 ... position sensor, 11
4...EGR control device, 201...EGR calculator,
202, 204, 303... Comparator, 203, 2
08...Driver, 301...Pulse width calculator,
302, 305...A/D converter, 304...
f/V converter, 306... oscillator, 307... timer, 401, 402... function generator, 403...
...Data selector. Note that the same reference numerals in each figure indicate the same parts.

Claims (1)

[Scope of Claims] 1. An exhaust gas recirculation control valve that controls the amount of part of the exhaust gas of the internal combustion engine that is recirculated to the intake system, a pressure detection means that detects the pressure in the intake pipe of the internal combustion engine, and the rotational speed of the internal combustion engine. an injection valve that is driven intermittently in synchronization with the rotation of the internal combustion engine to inject fuel into the internal combustion engine, and a valve opening time of the injection valve based on the detection information of each of the detection means. In the engine, the fuel control means determines the amount of fuel supplied when the exhaust gas recirculation control valve is in an operating state and in a non-operating state, respectively. In order to do this, the first data and the second data for correcting the detection information of the pressure detection means are preliminarily set to 2 by the intake negative pressure and rotational speed of the internal combustion engine.
a memory means that stores data corresponding to a plurality of operating states of the internal combustion engine that are dimensionally classified and reads out corresponding stored data based on each detection information of the pressure detecting means and the rotation speed detecting means; and the read data. means for calculating the valve opening time of the injection valve by correcting the detection information of the pressure detection means; and means for determining whether the exhaust gas recirculation control valve is in an operating state or a non-operating state, and based on this discrimination output, the first and means for appropriately selecting the second data. 2. The means for determining whether the exhaust gas recirculation control valve is in operation or non-operation is to detect the amount of valve movement of the exhaust gas recirculation control valve, and to determine whether the valve is in operation or non-operation based on the magnitude relationship of this detected value with respect to the set value. A fuel control device for an internal combustion engine according to claim 1, comprising a quantity detecting means.