JPS614837A - Electronic fuel injector - Google Patents

Abstract

PURPOSE:To prevent incorrect combustion of engine by adding an exhaust pressure correction factor based on the differential pressure between the supercharge pressure and the exhaust pressure for the correction of basic fuel injection time signal thereby performing A/F control under acceleration of engine associated with supercharger highly accurately. CONSTITUTION:An electronic fuel injector will determine the basic fuel injection time Ti from an injection time memory 17 with correspondence to the output signals ne, thetath from an engine rotation detector 15 and a throttle valve opening sensor 9. Then the injection time Ti is corrected through an arithmetic unit 20 with correspondence to the output signals P2, T2 from a supercharge pressure sensor 13 and a supercharge temperature sensor 14 thus to operate the injection time Tif for proper air/fuel ratio. Here, the differential pressure signal between the output signal Pr from an exhaust pressure sensor 21 and the signal P2 is obtained through a subtractor 23 to read out the exhaust pressure correction factor B from an exhaust pressure correction factor memory 25 with correspondence to said differential pressure signal and the rotation signal Ne. Then the injection time Tif is corrected through an arithmetic unit 26 with correspondence to said factor B.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an electronic fuel injection device, and in particular, to a method for adjusting the air-fuel ratio (A/F) during acceleration of a turbocharged engine to a suitable level. This invention relates to an electronic fuel injection device that can be controlled in a controlled manner.

(Prior Art) FIG. 3 is a schematic configuration diagram showing an example of a conventional turbocharged engine.

In the figure, 1 is a cylinder, 2 is a piston that moves up and down inside the cylinder 1, 3.4 is a suction valve and exhaust valve installed at the top of the cylinder 1 (intake valve and exhaust valve are closed, 5 is an intake pipe, 6 is 1''). It is the trachea.

7 is provided in the middle of the suction pipe 5, and fuel is injected into it!
i) 1? 1 is an injector; 8 is a throttle valve whose opening degree is varied according to the operation of an accelerator (not shown); and 9 is a throttle gap.

Reference numeral 10 denotes an exhaust turbine which is rotated by the exhaust pressure of the exhaust pipe 6. Reference numeral 11 is installed coaxially with the exhaust turbine 10, and rotates with the rotation of the exhaust turbine 10 to supply fresh air to the intake pipe 5.
12 is a relief valve (
13 is a supercharging pressure sensor, and 14 is a supercharging temperature sensor.

Further, FIG. 4 is a block diagram showing an example of a conventional control system of an electronic fuel injection device.

In the figure, the same reference numerals as in FIG. 3 represent the same or equivalent parts.

Reference numeral 15 denotes an engine rotation speed detection circuit that detects the engine rotation speed from, for example, a pulse signal on the next side of the ignition coil, and outputs an engine rotation speed detection signal Ne corresponding to the detected engine rotation speed.

16 is a throttle opening signal θth which is the output of the throttle opening sensor 9, and the engine rotation speed detection signal N.
(17 is an address converter that outputs a scheduled address signal obtained from 4), and 17 stores a basic fuel injection time signal Ti determined according to the throttle opening signal θth and the engine rotation speed detection signal Ne. The injection time is in memory.

18 is a first A/D converter that converts an analog boost pressure signal output from the boost pressure sensor 13 into a digital boost pressure signal P2; 19 is a signal from the boost temperature sensor 14; A second Δ/[] converter converts the output analog supercharging temperature signal into a digital supercharging temperature signal T2, 20 indicates the basic fuel injection time signal Ti, the supercharging pressure signal P2, and the supercharging temperature. This is a computing unit that receives the signal T2 and corrects the pressure and temperature of the intake air.

In the conventional electronic fuel injection device, as is clear from the above description of the configuration, the throttle opening signal θth corresponding to the opening degree of the throttle valve 8 and the engine rotation speed detection signal NO indicating the engine rotation speed are used. The address converter 16 is supplied with the address converter 16.

In the address converter 16, both the signals O[1] and Ne
An address signal corresponding to the address signal is output to @open time memory 17. As a result, the injection time memory 17 outputs a basic fuel injection time signal 7-i that is scheduled to be determined according to the throttle opening and the engine speed.

Next, the computing unit 20 corrects the signal T1 based on the basic fuel injection 11.1 signal Ti based on the supercharging pressure signal P2 and the supercharging temperature signal T2. Create an injection time signal 1-1 and output the signal.

An example of the correction calculation at this time is shown in equation (1).

Tif-Ti xP2/POxTO/-r2・-・-・
-(1) However, PO is 760mmH (1 (constant), T
o is 298°K (constant).

Note that the fuel injection time control signal actually applied to the injector 7 is created by a well-known appropriate method based on the corrected fuel injection time 114, which is the output of the generator 20, from the signal TI. , the explanation thereof will be omitted here. This point is specifically explained in Japanese Unexamined Patent Publication No. 56-1/18633j3.

As is clear from the above explanation, in the conventional turbo charge i; (=1) engine electronic fuel injection system, the boost pressure signal P2 is
and the supercharging temperature signal T2, and the valve opening time of the J: reinjector 7 is controlled by the signal obtained thereby.

(Problems to be Solved by the Invention) The above-mentioned conventional technology had the following problems.

(1) During acceleration 11.1, when the throttle valve 8 is suddenly opened from the open state, for example, the amount of fuel injected by the injector 7 increases accordingly. However, when the exhaust turbine 10 starts rotating, the throttle valve 8
It's better than the sudden onset of.

For this reason, the pressure feeding of fresh air to the suction pipe 5 is also delayed, so if only the conventional correction of the supercharging pressure and supercharging temperature is performed, the A/F becomes too rich and the engine is in an incorrect combustion state.

(2) And, the above-mentioned tendency is
This is especially noticeable during periods when both problems occur, that is, in the case of large turbocharged engines that aim for high output with large valve overlap.

The present invention has been made to solve the above-mentioned problems.

(Means and operations for solving the problems) In order to solve the above problems, the present invention focuses on the temporary increase in exhaust pressure by F due to the delay in the rotation start-up of the exhaust turbine, and
A tJI pressure correction coefficient, which is based on the differential pressure between the boost pressure and the exhaust pressure, is added to the correction of the basic fuel injection time signal T1 to calculate the A/
The present invention is characterized in that F is controlled with even higher precision, thereby preventing the occurrence of improper combustion in the engine.

(Example) The present invention will be described in detail below with reference to the drawings.

FIG. 1 is a schematic diagram of a turbocharged engine according to an embodiment of the present invention. In the figure, the same reference numerals as in FIG. 3 represent the same or equivalent parts. In the figure, 21 is an exhaust pressure sensor. .

Further, FIG. 2 is a block diagram showing an embodiment of the control system of the present invention for an electronic fuel injection device. In the figure, the first
The same reference numerals as in the figures and FIG. 4 refer to the same or equivalent parts.

In FIG. 2, 22 is a third A/D converter that converts the analog exhaust pressure signal output from the exhaust pressure sensor 21 into a digital exhaust pressure signal pr; 23 is a third A/D converter that converts the analog exhaust pressure signal output from the exhaust pressure sensor 21; The supercharging pressure signal P2 which is the output of the A/D converter 18 of No. 1 is input, and the differential pressure signal (P2-
This is a subtracter that outputs a p r signal) signal.

A second address converter 24 outputs an address signal to be determined using the (P2-Pr) signal and the engine speed detection signal Ne from the engine speed detection circuit 15 as parameters.

25 is an exhaust pressure correction coefficient memory in which an exhaust pressure correction coefficient B determined according to the (P2-Pr) signal and the engine rotation speed detection signal Ne is stored; This is a second computing unit that inputs the fuel injection time signal Ti[ and the exhaust pressure correction coefficient B, and performs correction based on the differential pressure between the boost pressure and the exhaust pressure.

In the electronic fuel injection device 9A of this embodiment, as is clear from the above description of the configuration, the subtracter 23 generates a differential pressure signal between the boost pressure signal []2 and the exhaust pressure signal Pr, that is, (1
'2''-Pr) signal is created.

The second address converter 24 outputs an address signal corresponding to the (P2-Pr) signal and the engine rotation speed detection signal Ne from the engine rotation speed detection circuit 15 to the JJt pressure correction coefficient memory 25.

As a result, the exhaust pressure correction coefficient 13, which is scheduled to be determined according to the difference between the supercharging pressure 1111 and the sweat peak, is read out from the 1-1 pressure correction coefficient memory 25.

Note that the exhaust pressure correction coefficient read out in this way is
The exhaust pressure correction coefficient is obtained empirically or experimentally and stored at a predetermined location in the exhaust pressure correction coefficient memory 2. However, this exhaust pressure correction coefficient generally tends to increase when the engine load is high and the engine rotation is high.

Next, the second arithmetic unit 26 further corrects the corrected fuel injection time signal Tif from the arithmetic unit 20 using the exhaust pressure correction coefficient B to obtain the fuel injection time signal of this embodiment. In other words, the fuel injection time signal Tix at the optimum air-fuel ratio
occurs.

An example of the correction calculation at this time is shown in equation (2).

T ix = T if (14B) -...12) Note that the fuel injection time control signal actually applied to the injector 7 is determined from the fuel injection time signal Tix at the optimum air-fuel ratio, which is the output of the second sieve 26. is created by a well-known appropriate method, as in the conventional example. Therefore, this explanation will be omitted.

As is clear from the above description, according to this embodiment,
When the turbocharged engine accelerates, the amount of air forced into the intake pipe 5 becomes smaller than the appropriate amount due to the rotation delay of the exhaust turbine 10, and the amount of fuel injection decreases in proportion to the decrease in the amount of intake air b1. It is possible to appropriately control the correction in the negative direction.

Further, during deceleration, the compressor cannot rapidly reduce its rotation due to inertia, so the amount of air to be pumped is larger than the appropriate amount. However, if this embodiment is used, the fuel injection amount can also be appropriately controlled in the positive direction.

(Effects of the Invention) As is clear from the above description, according to the present invention, the following effects are achieved.

(1) During acceleration 11.1, the fuel injection amount can be appropriately controlled in the negative direction, and even during deceleration, the fuel injection direction can be appropriately controlled in the positive direction if desired. Optimal A/F 4! Therefore, it is possible to prevent an incorrect combustion state of the engine.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of a turbocharged engine according to the present invention, FIG. 2 is a block diagram showing an embodiment of a control system of the present invention for an electronic fuel injection device, and FIG. FIG. 4 is a schematic configuration diagram showing an example of a conventional turbocharged engine, and FIG. 4 is a block diagram showing an example of a conventional control system for an electronic fuel injection device. 9... Throttle opening sensor, 13... Boost pressure sensor, 14... Boost temperature sensor, 15... Engine rotation speed detection circuit, 16.24... Address converter, 1
7...Injection time memory, 18.19.22...A/
D converter, 20.26... Arithmetic unit, 21...tII
Atmospheric pressure sensor, 23...Subtractor, 25...1 no 1 pressure correction coefficient memory Patent attorney Michito Hiraki and 1 other person Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] (1) Means for creating a basic fuel injection time signal from a throttle opening signal and an engine speed detection signal, a means for generating a supercharging pressure signal, a means for generating a supercharging temperature signal, and the basic fuel In an electronic fuel injection device, means for generating an exhaust pressure signal in an electronic fuel injection device having means for adding correction to the injection time signal using the boost pressure signal and the supercharging temperature signal and outputting a corrected fuel injection time signal; a subtracter that outputs a differential pressure signal between the boost pressure signal and the exhaust pressure signal;
An exhaust pressure correction coefficient memory that stores an exhaust pressure correction coefficient using the differential pressure signal and engine speed detection signal as parameters, and an exhaust pressure correction coefficient read from the memory and the corrected fuel injection time signal. 1. An electronic fuel injection device comprising means for generating a fuel injection time signal at an optimum air-fuel ratio.