JPS6062639A - Fuel injection device of engine - Google Patents

Abstract

PURPOSE:To improve interporation accuracy for a basic fuel injection amount with small storage capacity by evaluating the basic fuel injection amount based on a fuel injection amount in responce to intake air negative pressure in a standard operation state and data associated with deviation of filling efficiency. CONSTITUTION:A fuel injection device of an engine includes a pressure detecting means 15 for sensing intake air negative pressure in an air intake passage 5 downward a throttle valve 7, and a number-of-revolutions detecting means 18. It further includes an arithmetic operation means 21 for a reference fuel injection amount in an engine reference operation state, a storage means 20 having a data previously stored therein concerning a difference of filling efficiencies between the aforesaid engine reference operation state and that at a set number-of-engine revolutions, a data readout means 22 for reading out data corresponding to intake air negative pressure and the number of engine revolutions, and a correcting means 23 for correcting the reference fuel injection amount. A basic fuel injection amount is evaluated from the data concerning the difference of the filling efficiencies and the reference fuel injection amount. In case of no data read out in the above-described data, filling efficiency data are interporated to evaluate the basic fuel injection amount.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a fuel injection device for an engine, and more particularly, to an engine fuel injection device, which calculates the amount of intake air based on the intake negative pressure downstream of the throat valves in the intake passage and the engine speed. The present invention relates to an improvement in the fuel metering method using the so-called speed density method, which calculates IC fuel@躬m according to the amount of fuel.

(Prior Art) Conventionally, as disclosed in Japanese Patent Laid-Open No. 57-143135, for example, as a fuel injection device for this type of engine, a basic fuel injection f! l
(Pulse width of injection pulse) is stored in large numbers in correspondence with the intake negative pressure and engine speed, and when the engine is running, J3 is stored and the amount of intake air at each moment is determined from the basic fuel injection time data. After reading out the corresponding basic fuel injection time based on the actual prefectural air negative pressure and engine speed,
It is known that this injection pulse is output to a fuel injection valve to measure the amount of fuel to be supplied to the engine.

By the way, in the fuel injection device for an engine as described above, if data corresponding to the actual intake negative pressure and engine speed during the basic fuel injection time arc is not stored in advance, the Basic fuel injection 11 to be read based on basic fuel injection time data
．． It is designed to interpolate one interval.

However, in the above-mentioned conventional type, Kimoto fuel only 1! ? '
-1! JJ time data There is a large difference between adjacent data, that is, in the basic fuel injection Q'1 time curve drawn three-dimensionally with intake negative pressure and engine speed as the X and Y axes, respectively. If the data to be read out is not stored because the slope is too large, the resolution of multiple resolutions between data located in the vicinity during interpolation calculation will be reduced and the interpolated viscosity of the basic fuel injection time will be reduced. This has the disadvantage that fuel metering control cannot be performed accurately.

Therefore, for example, the basic fuel injection time data m stored in advance is increased as much as possible to reduce the difference between adjacent data and increase the resolution between adjacent data. It is possible to improve the interpolation accuracy, but
This approach has the disadvantage of significantly increasing data storage capacity.

(Object of the Invention) The object of the present invention is to set the reference fuel injection amount according to the intake negative pressure at a predetermined dedicated engine rotation speed at J31:J engine operating state ta<reference engine operating state) to By inputting and storing data related to the deviation in filling efficiency with respect to the reference engine operating state in advance based on intake negative pressure and engine rotation speed, it is possible to compare adjacent data related to the deviation in filling efficiency. The purpose of this invention is to reduce the difference in data, that is, to make the slope of the characteristic curve of the data gentler, to increase the resolution, and thereby to improve the interpolation accuracy of the basic fuel error with a small storage capacity.

(Structure of the invention) What is the solution of the present invention to achieve this purpose? As shown in FIG. 1, the means includes a pressure detection means 15 for detecting the intake negative pressure downstream of the throttle valve 7 in the intake passage 5, and a rotation speed detection means 18 for detecting the engine rotation speed. , standard constriction 1 injection for calculating a reference fuel injection amount in an engine operating state at a preset set rotation speed based on the output of the pressure detection means 15; a storage means 20 in which data related to the deviation t of the filling efficiency with respect to the state is stored in advance in correspondence with the intake negative pressure and engine rotation; and the pressure saw detection means 15.
J3 an arter reading means 22 for reading out data corresponding to the intake negative pressure and engine rotational speed from the storage means 20 based on the output of the rotational speed detection means 18; Based on the above-mentioned base 4 (correcting means 23 for correcting the reference fuel injection amount of the fuel injection amount adjustment means 21), calculation of the basic fuel injection amount corresponding to the current intake air amount and engine speed is performed. This is done by calculating the data related to the efficiency deviation and the reference fuel injection amount according to the intake negative pressure at the set rotation speed.

As a result, in the present invention, if data to be read out is not stored in the data related to the deviation in filling efficiency, first the filling efficiency data is calculated with high accuracy (interpolated), and then the current intake air amount and The basic fuel injection amount is calculated with high accuracy according to the engine speed.

(Effect of the invention) Therefore, according to the present invention, the basic fuel 1.11 injection 0Jf
Since the stoppage of fl is performed based on the standard combustion per blow according to the intake negative pressure in the standard engine operating state, and the data related to the deviation of the charging efficiency with respect to the above-mentioned standard engine operating state. With a small memory content, it is possible to reduce the difference between adjacent data in the data related to the deviation in filling efficiency and increase the resolution. This makes it possible to improve the interpolation accuracy with respect to intake negative pressure, and further improve accurate fuel metering control.

(Example) Hereinafter, an example as a specific example of the technical means of the present invention will be described in detail based on the drawings.

In FIG. 2, 1 is an engine, 2 is a combustion chamber formed by a cylinder 3 formed in the engine 1, and a piston 4 rotatably inserted into the cylinder 3, and 5 is an air cleaner at one end. 6, and the other end opens into the combustion chamber 2, and is an intake passage for supplying intake air to the combustion chamber 2, and a throttle valve for controlling the amount of intake air is provided in the intake passage 5. 7L! 3 and the fuel injection valve 8 which is located upstream of the throttle valves 1 to 7 and injects fuel 1'11.
are respectively arranged tL'c. In addition, 9 is an exhaust passage whose one end is open to the combustion chamber 2 and whose other end is opened to discharge exhaust gas from the combustion chamber 2, and in the middle of the air passage 9. A catalyst device 10 for purifying exhaust gas is provided. Note that 11 is installed at the frontage of the intake passage 5 to the combustion chamber 2 (intake force), and 12 is the intake force installed at the frontage of the combustion chamber 2 of the exhaust passage 9.
An exhaust valve 13 installed at the frontage of the intake passage 5 heats the downstream side of the throat valve 7 with engine cooling water.
This is an intake air heating device.

Furthermore, 14 is a throttle opening sensor that detects the opening of the throttle valve 7, 15 is a negative pressure sensor that detects the intake negative pressure downstream of the throttle valve 7 in the intake passage 5, and 16 is an intake air heating device 13. Cooling water temperature sensor that detects the cooling water temperature of
17 is an air-fuel ratio sensor consisting of a 02 sensor that detects the air-fuel ratio based on the oxygen concentration in 1 gas upstream of the catalyst device 10 in the air passage 9, and 18 is an engine rotation that detects the rotation speed of the engine 1. The negative pressure sensor 15 constitutes a pressure detection means, and the engine rotation speed sensor '18 constitutes a rotation speed detection means (14).The detection signals of each of the sensors 14 to 18 are as follows. The fuel noise Q/1 is input to one controller that controls the valve 8, respectively.

Inside each of the above controllers 1-0-1, see Figure 4 (A) in advance.
Set engine speed as shown in (e.g. 700r11)
The reference fuel injection amount characteristics with respect to the intake negative pressure in the engine operating state (reference engine operating state) in 1II) are input and stored, and the reference fuel injection amount characteristics are input and stored as shown in FIG. The charging efficiency data under the corresponding engine operating conditions are based on the above basis j11. Based on the charging efficiency when the engine is running, it is 1.5f (r I J ), which is input and stored in advance in accordance with the engine speed and intake negative pressure, etc. Then, a memory stage 20 is also used in which data related to the difference in charging efficiency from the standard engine operating state is stored in advance in accordance with the intake negative LE2 and engine speed. There is.

Next, the operation of the rollers 1 to 10 will be explained based on the flowchart t--+- of FIG. , Flowchart 1 shows a processing operation when data corresponding to the current engine speed d3 and intake negative pressure is not stored in advance in the filling efficiency data shown in FIG. 5 of the L storage means 2o, First, the star is 1~, and the first stage is '7' S +
After initializing all 11(f) in the controller 19 in IJJ5, in the second step S2, the current engine rotation speed ro@ is read based on the engine rotation speed value from the rotation speed sensor 18. At the same time, in the third step s3, J5 does not read out the current intake negative pressure ba based on the negative pressure signal from the negative pressure sensor 15.

Subsequently, in a fourth step S4, as shown in FIG. 6, four filling aids near the position corresponding to the current intake negative pressure ba and engine speed ro are selected from among those stored in advance as filling efficiency data. , I-data A(r+
, b 1 ), B(r 2 , l] 1 ).

C (I'+, t) 2), D (rz, 1) 2) e are read out, and in the fifth step S5 r: coordinate point (r+,
l) +) (rz, l]+) (r o , 1
(r+, bl) and (r l) when internally divided by 31)
11゛1) What distance corresponds to the value Δχ and the coordinate point ("
+ + 11 + ) and (rl, bz) as (rl
, bθ), (rl, b+) is (r+.

11 o)) is calculated.

After that, in the sixth step S6, the filling efficiency data E(ro, b+) at the point (1・0°1)1) is converted into data A(r+,I]+) and B(r,+,I). +) based on J-ru, that is, A(r+, bl)-i-(B
(rz,l)+)-A(l'+,rl))・△χ/16
(rl 6J G, L coordinate point (r+, ri+) and ("2
11) At the same time, in the seventh step S7, the coordinate point (ro,
b2) 'C filling efficiency data F(ro, b2) is calculated based on data c(rl,l)2>a3 and D(r2.b2>, i.e., same as above) C(1'
+, 1) 2) + (D(r2+1)2) C(rl.

b2))・Δx/16(r16J is the coordinate point (rl.

1) Calculate the value corresponding to the distance between 2) and (r2.b2).

Then, in the eighth step S8, the coordinate point (ro, bo
) filling efficiency data MAR(ro, bO) above data E(ro, b+) J5 and F(rl), l
] 2), that is, E (r 0
.

11+ )-t (F(ro, +12)-E(ro,
Perform the demonstration of tl+ ))・△y/16.

Subsequently, in the ninth step S9, the reference fuel injection uJ f
From the fl characteristic (Fig. 4 (a)), after adjusting the basic fuel injection Qo according to the current intake negative pressure bO, set the pulse width τ0 of the reference injection pulse corresponding to the basic fuel injection port Qo. Filling efficiency data MAP (ro.

The corrected injection pulse width τ is calculated by multiplying the injection pulse width τ, and is outputted to the fuel i3 [injector 8] at a predetermined injection timing (for example, at the top dead center of the piston), and the process returns to the second step S2.

Therefore, the reference fuel injection amount calculation means 21 is configured to calculate the reference fuel injection amount (reference fuel injection pulse width τ0) in the reference engine operating state from the reference fuel injection amount characteristics in J3 in the first half of the ninth step S9. At the same time, the current intake negative pressure b l) at the eighth step S8 is
The data reading means 22 is configured by calculating (r o , l) o ).

Further, the filling efficiency data MAP (r U) read out by the data reading means 22 by calculating the correction allocation pulse τ d3 at 31' after the ninth step S9.

A correction means 23 is configured to correct the reference fuel II injection amount (reference fuel 1 injection pulse width τO) based on b, o).

Therefore, in the above embodiment, the filling efficiency data in FIG. 5 is input and stored in a form with the filling efficiency in the reference engine operating state as the reference (rlJ), so that the filling efficiency data is The characteristic curve for each predetermined engine speed is shown in Figure 4 (b), which is a fuel injection amount characteristic curve at each predetermined engine speed as shown in Figure 4 (c), drawn based on the fuel injection amount at the set engine speed. It becomes equal to the combustion 1 injection fJJ m characteristic curve, and its slope is sharply smaller (by the slope of the fuel injection amount characteristic at the set rotation speed) compared to the conventional slope shown in FIG. As a result, if the data corresponding to the engine speed rO and the intake negative pressure 110 are not stored in advance in the filling efficiency data of FIG. 5, the filling efficiency data MAP Do in J5.

b1]) The interpolation accuracy for the intake negative pressure is significantly improved compared to the conventional one. Therefore, by improving the interpolation accuracy, fuel injection amount control can be performed more accurately, which in turn ensures that the air-fuel ratio of the air-fuel mixture supplied to the engine is maintained at the set air-fuel ratio, improving engine operating performance and Emission performance can be improved.

In the above embodiment, the storage means 20 (controller 19
) has previously stored filling efficiency data based on the filling efficiency value at the reference engine operating state, but data related to the deviation of the charging efficiency from the other reference engine operating state, such as Jj i%l+engine operating state. The fuel injection amount nA OJ fft y3 may be stored in advance. In this case, tlj'A in the ninth step of the flowchart in FIG. 3 is addition.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing the configuration of the present invention, Figs. 2 to 6 show embodiments of the invention, Fig. 2 is a general schematic diagram, and Fig. 3 explains the operation of the controller. 4(A) to 4(C) are operation explanatory diagrams, and FIG. 5 is a diagram showing the memory contents of controller 1 [1-A.
The figure is an enlarged view of the operation of the main part of FIG. 5. 5... Intake passage, 7... Throttle valve, 15...
Negative pressure sensor (pressure detection means), 18... rotation speed sensor (rotation speed detection means), 20... memory means, 21...
Reference fuel '3 [injection amount calculation means, 22... arc reading means, 23... correction means. Figure 3 jl! 4FB (b) (c) 6th prisoner

Claims (1)

[Claims] (1) Preset based on the pressure detection means that detects the intake negative pressure downstream of the throat valves 1 to 1 in the intake passage, the rotation speed detection means that detects the engine rotation speed, and the output of the pressure detection means. a reference fuel injection amount calculating means for calculating a reference fuel injection amount in an engine operating state at a set rotation speed;
A memory means that stores arcs related to charging efficiency deviations in the engine operating state at the set rotational speed in advance in correspondence with intake negative pressure and engine rotational speed, and outputs of the pressure detection means and rotational speed detection means. data reading means for reading data corresponding to the intake negative pressure J3 and engine speed from the storage means based on the data reading means; and a reference fuel J'i+ of the reference fuel injection amount section frame means based on the data read by the data reading means. A fuel injection DJJ device for an engine, comprising a correction means for correcting injection m.