JPS59122736A - Electronic fuel injection equipment - Google Patents

Abstract

PURPOSE:To eliminate the necessity of a pressure sensor for atmospheric pressure measurement by controlling the quantity of fuel, while regarding the value of a supercharging pressure detecting pressure sensor as being equal to the atmospheric pressure when the difference between the atmospheric pressure and supercharging pressure during the operation is nearly equal to zero. CONSTITUTION:The quantity of fuel supplied from an injection valve 8 is corrected first by means of supercharging pressure, which is detected by a pressure sensor 10, and then by the atmospheric pressure. The value of the atmospheric pressure used at that time is that measured by the pressure sensor 10 during the operation, in which the difference between the atmospheric pressure and the supercharging pressure can be regarded as nearly zero, and stored in a register. With this contrivance, a pressure sensor for atmospheric pressure measurement can be eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electronic fuel injection system for a supercharged engine.

Conventionally, for example, among electronic fuel injection devices for supercharged engines installed in vehicles, devices that control the amount of fuel injection by sensing supercharging pressure, which is the pressure obtained by supercharging, A pressure sensor for detecting supercharging pressure is installed in the intake passage downstream of the compressor wheel of the feeder to detect the supercharging pressure, and atmospheric pressure is also detected in the air cleaner etc. on the upstream side of the compressor wheel. , a pressure sensor is provided (as a prior art, Japanese Patent Application Laid-Open No. 57-526
No. 46 and No. 57-52647). The reason for providing a pressure sensor for atmospheric pressure is as follows.

A supercharger operates by driving a turbine wheel installed in the engine's exhaust passage by the exhaust gas.
The compressor wheel in the intake passage rotates to perform supercharging, and in order to perform stronger supercharging (compression of desired air), the exhaust pressure must be significantly increased. When the exhaust pressure increases due to strong supercharging, the ability to discharge gas from the engine's sills decreases, and in the end the intake paper does not increase enough to supercharge. On the other hand, when a vehicle is driven under low pressure, such as at a high altitude, the compressor wheel must rotate much faster to ensure intake air wax, just as when driving at a normal low altitude. . That is, in highlands, etc., the exhaust pressure for rotating the turbine wheel must be increased, and the intake and exhaust capacity is lower than in lowlands. Therefore, if the boost pressure is simply measured using a pressure sensor, even if the boost pressure is the same, the amount of intake and displacement will differ depending on the difference in atmospheric pressure. Even if the relationship between
When the atmospheric pressure decreases at high altitudes, etc., the number of fuel injection ducts becomes too large, resulting in a problem that the optimum mixture ratio cannot be obtained. Conventionally, a pressure sensor for atmospheric pressure is provided in addition to the pressure sensor for boost pressure, and the fuel injection pattern is corrected by the pressure sensor for atmospheric pressure, so that the optimal mixture ratio can always be obtained.

However, in the conventional configuration described above, two pressure sensors are required, which increases the cost.
Therefore, there is a problem that the measurement variation factors increase and errors become large, making it impossible to perform accurate fuel injection control.

In view of the above-mentioned problems, the present invention aims to eliminate the need for an atmospheric pressure injector, reduce costs, reduce variation factors, and perform accurate fuel injection control. The value of the pressure sensor for detecting boost pressure in the M rotation state where the difference between It is characterized by having a circuit that controls the amount of fuel.

Next, the present invention will be explained based on the drawings. FIG. 1 is a conceptual diagram of an electronic fuel injection device according to the present invention.

An intake passage 4 opens into the combustion chamber 2 in the cylinder 1 through an intake valve 3, and an exhaust passage 6 opens through an exhaust valve 5. The upstream end of the intake passage 4 communicates with an air cleaner 7. .

Also, in the passage 4, from the combustion chamber 2 side, an injection port of an electromagnetic injection valve 8, a throttle valve 9, and a pressure sensor 10 for detecting supercharging pressure are installed.
, a supercharger 11 , and a temperature sensor 12 for detecting intake air temperature are arranged, and a combustion wheel 13 provided in the supercharger 11 is connected to a turbine wheel (
(not shown) so that they rotate together. Further, the fuel in the fuel tank 14 is sent to the injection valve 8 by a fuel pump 15.
Excess fuel pumped out is returned to tank 14 via pressure regulator 16. Here, 17 is a temperature sensor for the cylinder l.

On the other hand, the control unit 18 having an arithmetic circuit has
An electric signal corresponding to the opening degree of the throttle valve 9, an electric signal corresponding to the pressure in the intake passage 4 detected by the pressure sensor 10, an electric signal from the temperature sensor height 12 that detects the intake temperature, and the temperature of the cylinder 1 are detected. An electrical signal from a temperature sensor +j17 and an electrical signal from a rotational speed sensor (not shown) which picks up the rotational speed of the crankshaft 19 as a pulse signal are respectively input. Also, the unit 18 of these input signals
The results of the calculations within are used to control the opening and closing of the injection valve 8, as well as the output. The arithmetic circuit of unit 18 performs arithmetic operations according to chart 70 shown in FIG. First, the engine load (torque) is calculated from the opening degree of the throttle valve 9 (FIG. 1) and the engine speed, and the basic amount of fuel injected from the injection valve 8 (FIG. 1) is determined.

Next, the fuel amount is corrected by the boost pressure detected by the pressure sensor 10 (FIG. 1), and further corrected by the atmospheric pressure. The atmospheric pressure value in this case is pressure sen''/-10 (m 1
(Fig.) In this case, the pressure measured in the operating state in which the difference between the atmospheric pressure and the supercharging pressure can be considered to be approximately zero is used, and the pressure is stored in the register. That is, as shown in Fig. 3, a region where the difference between boost pressure and atmospheric pressure can be considered to be approximately zero is experimentally determined for engine load derived from throttle opening and engine speed, and when the load is at a predetermined value. The pressure detected by the pressure sensor '+j1o (Fig. 11) when the pressure becomes smaller than l (for example, during idling, deceleration, or gear change) is regarded as atmospheric pressure and stored in the register. This stored value is updated every time the operating state falls within the predetermined range. After the atmospheric pressure is corrected in this way, other corrections are made as shown in FIG. This correction is performed using the detected value of a temperature sensor v12.17 or the like (FIG. 1). The corrected fuel amount is then delivered to the injection valve 8 (FIG. 1) to control the injected fuel amount to an optimum state.

Note that the pressure sensor 10 in FIG. 1 uses a force balance type pressure sensor using a diaphragm or bellows in the pressure receiving part, an electrostatic valley ξ( type), a strain gauge type pressure sensor, etc., and the pressure received by the pressure receiving part is 7[ In addition, as the temperature sensor 12, 17, a variable resistance temperature sensor, a thermocouple, etc. are used, and the temperature is detected in a 4-gas manner. As the sender, either a contact type or a non-contact type can be used at the same time.

Next, the operation of the fuel injection device according to the present invention will be described using, as an example, a case where the vehicle is traveling from a flatland (lowland) to a highland.

First, when the vehicle is on level ground and idling,
The rotation speed of the compressor wheel 13 in FIG. 1 is low and substantially no supercharging is applied, and the engine load is at a predetermined value I.
! (Figure 3) Below. Therefore, the pressure measured by the pressure sensor 1O is stored in the register in the control unit 18 as atmospheric pressure. Next, when the vehicle begins to gain footing, the amount of fuel to be injected is determined according to the flow shown in FIG. Here atmospheric pressure is the value in the previously stored register. The value in this register is the actual measured value of atmospheric pressure and pressure sensor 1.
An operating state where the difference from the value measured at 0 can be considered to be approximately zero (
It is updated each time the pressure sensor 10 is decelerating, idling, or changing gears, and the value measured by the pressure sensor 10 at that time is stored as atmospheric pressure. Therefore, even if the atmospheric pressure changes one after another as the car (company) ascends to a higher altitude, the stored atmospheric pressure value in the register will be updated with a certain frequency. When the injection fuel level is determined according to the flow shown in FIG. 2, the updated stored value is used as the atmospheric pressure, and the atmospheric pressure correction is performed accurately.

As explained above, according to the present invention, there is a pressure sensor for detecting supercharging pressure when the difference between atmospheric pressure and supercharging pressure is substantially zero. 1
The value of 0 is regarded as atmospheric pressure and stored, and the memory and normal M
Since we have installed a circuit that controls the fuel supply range by comparing the boost pressure at the time of k, there is no longer a need for a pressure sensor for measuring atmospheric pressure, which was required on the conventional side, which reduces the number of parts and reduces costs. This has the advantage that more accurate fuel injection control can be performed because the number of failed devices is reduced and the factors for variation are reduced.

In carrying out the present invention, the arithmetic circuits in the control unit 18 are not limited to those shown in FIG. 2, and can be rearranged as desired. For example, other corrections may be made to the boost pressure correction of 13+7.

Furthermore, although the above embodiment describes a type of fuel injection device that determines the amount of fuel based on the throttle opening degree and engine speed, it may also be adopted as a type that determines the amount of fuel based on boost pressure and engine speed. I can do it. In this case, a pressure sensor fio' may be provided on the exhaust passage 6 side instead of the pressure sensor lo, or both pressure sensors 10 and 10' may be provided for more accurate control.

[Brief explanation of the drawing]

FIG. 1 is a graph showing the relationship between the pressure difference between atmospheric pressure and boost pressure and the engine load. 10・
...Pressure sensor for detecting boost pressure, 11...Supercharger

Claims (1)

[Claims] An operating state in which the difference between atmospheric pressure and supercharging pressure is approximately zero in an electronic fuel injection device that has a pressure sensor for detecting supercharging pressure that detects the supercharging pressure of a supercharged engine and controls the amount of fuel supplied. An electronic fuel injection device that has a circuit that stores the value of the pressure heel height for detecting boost pressure as atmospheric pressure and compares that memory with the boost pressure during normal operation to control the amount of fuel to be supplied. .