JPS60212651A - Electronic control type fuel injector - Google Patents

Abstract

PURPOSE:To prevent the retardation, breathing, etc. of an engine by setting the air-fuel ratio to rich side for a prescribed time after the rise of the cooling-water temperature to a prescribed value ensuring perfect warming, after the engine starts, in the captioned apparatus for operating an internal-combustion engine with an aimed lean air-fuel ratio. CONSTITUTION:When an ignition switch 25 is turned ON, an electronic controller 50 judges if the cooling-water temperature detected by a water-temperature sensor 12 is over a prescribed value or not, and in case of NO, namely before perfect warming, a fuel injection valve 16 is controlled so that the lean air-fuel ratio feedback control is carried-out according to the lean air-fuel ratio correction coefficient set on the basis of the output of a limit current type oxygen concentration sensor (lean sensor) 10. When the cooling-water temperature rises to a prescribed value ensuring perfect warming, the lean air-fuel ratio feedback control is carried-out according to the lean air-fuel ratio correction coefficient for bringing the air-fuel ratio to the rich side during a prescribed time from the rise of the cooling-water temperature, and retardation, breathing, etc. of the engine during transition are prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to an electronically controlled fuel injection device for operating an internal combustion engine at a target lean air-fuel ratio.

-1- [Prior art] Generally, residual oxygen in exhaust gas l! In an electronically controlled fuel injection system that is equipped with a lean sensor that generates a current proportional to 1°C and operates an internal combustion engine at a target lean air-fuel ratio,
As shown in the figure, when the cooling water ITHW is THW2 (e.g. 80°C) or higher and the engine is fully operated, and during lean air-fuel ratio (A/F) feedback control, the target air-fuel ratio (A/F) is
/F) is set to the largest value, and the cooling water ITHW
is TI-IWl (e.g. 55℃) or more and THW2 or less, and during lean A/F feedback control,
The target A/F is set to the rich side, that is, the dark side, compared to the target all A/F at the time of complete warm-up, and the cooling water temperature THW
During oven control with an air-fuel ratio (A/F) of THW1 or less, the target A/F is set further to the rich side. However, although the target A/F is shown as a constant value in the diagram after the complete 11flI, the target Δ/F is actually determined according to the engine speed and load.

However, if the target A/F is set as above and the internal combustion engine is operated, the A/F speed will increase after the engine starts and before it is completely warmed up.
When shifting from F feedback control to lean A/F feedback control after complete warm-up, problems such as so-called engine sluggishness and breathing tend to occur.

By the way, in this type of electronically controlled fuel injection device, the fuel injection fiTAU is expressed by the following formula, that is, TAU=TPxFW
It is determined by Lx (1+FASE+KLEAN+...). In this equation, TP represents the basic injection amount, FWL represents the warm-up increase coefficient, and FASE represents the post-start increase coefficient. KLEAN is a correction coefficient for making the target air-fuel ratio into a lean air-fuel ratio, and if the target air-fuel ratio is made into the stoichiometric air-fuel ratio, the value is "1" (in the present invention, it is called the lean air-fuel ratio correction coefficient). ) is set as shown in Fig. 2 according to the cooling water temperature and control mode before it is completely warmed up, while after it is completely warmed up, it is set as shown in the following formula, that is, KLEAN=KLEANNExKLEANPM. -3- Defined by. In this formula, the coefficient KLEANN
E and the coefficient KLEANPM are determined corresponding to the engine speed NE and the load (intake pipe pressure) PM, respectively, as shown in Figs. 3 and 4, and the lean air-fuel ratio correction coefficient KLEAN is set to a value of 1 or less. Ru.

[Object of the Invention] The present invention has been made in view of the above, and includes at least the following transition, that is, from lean A/F feedback control after engine startup and before complete warm-up to lean A/F feedback control after complete warm-up.
When there is a transition to F-feedback control, the value of the lean air-fuel ratio correction coefficient is increased for a predetermined period from the transition point to increase the fuel injection amount, thereby reducing engine sluggishness, breathing, etc. during this transition. The purpose is to prevent

[Structure of the Invention] Therefore, as shown in FIG. 5, the electronically controlled fuel injection device of the present invention includes a calculation means M1 that determines the fuel injection amount by an injection amount calculation formula including a lean air-fuel ratio correction coefficient, and 41 In an electronically controlled fuel injection system that operates engine M2 at a target lean air-fuel ratio, when the cooling water temperature rises to a predetermined temperature indicating complete warm-up after engine startup, the correction amount is set to a constant value larger than the value rOJ. Then, a means M3 is provided for setting a value that attenuates to the value "0" as time passes or becomes rOJ immediately after a predetermined time, and adds the lean air-fuel ratio correction coefficient to this correction amount. It is characterized by a new lean air-fuel ratio correction coefficient. In addition, other symbols M4, M5, M
6 represents an electronic control unit, a lean sensor, and a fuel injection valve, respectively.

[Embodiment] Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 6 to 9.

FIG. 6 shows the overall configuration of an electronic control system for an internal combustion engine including an electronically controlled fuel injection device according to an embodiment of the present invention.

In the figure, an electronic control device 50 with a built-in microcomputer receives detection signals from sensors as described below to detect various operating states of the internal combustion engine 1, and performs fuel injection control, ignition timing control, and idle rotation. Performs numerical control and EGR (exhaust gas recirculation) control.

As sensors for detecting the operating state of the internal combustion engine 1, the intake manifold 2 of the intake system includes a thermistor-type intake temperature sensor 5 that detects the temperature of intake air after being purified by the air cleaner 3, and an accelerator pedal. A potentiometer type throttle sensor 8 is provided which detects the opening degree of a throttle valve 7 which is linked to the throttle valve 6 and controls the amount of intake air. Further, the surge tank 18 is provided with an intake pressure sensor 4. On the other hand, the exhaust manifold 9 of the exhaust system is provided with a limiting current type oxygen concentration sensor, ie, a lean sensor 10, which detects the residual oxygen concentration in the exhaust gas. Furthermore, the cylinder block 11 of the internal combustion engine 1
There is a thermistor-type water temperature sensor 12 that detects the cooling water temperature.
is provided. Further, the ignition system distributor 13 is provided with an electromagnetic pickup type rotation sensor 15 for detecting the rotation speed and reference angular position of the rotor 14 in order to detect the rotation speed and reference piston position of the internal combustion engine 1. There is.

On the other hand, the objects controlled by the electronic control device 50 include the electromagnetically driven injectors provided in the intake manifold 2, that is, the fuel injection valves 16 and the cold start injectors 17, as well as the upstream side of the throttle valve 7 and the surge tank 18. There is an electromagnetically driven fj type or diaphragm type ISO (idle speed control) valve 2o provided in the bypass passage 19 between the Electromagnetic drive type F
There is an ORI+11 III valve 22, and an igniter 23 for the ignition system. In addition, other symbols in the figure, 24.2
5, 26, and 27 indicate the battery, ignition switch, fuel tank, and fuel pump, respectively. Further, 25a indicates an ignition terminal, and 25b indicates a starter terminal.

Next, FIG. 7 shows a block diagram of the electronic system 011811250.

51 inputs and calculates signals output from each sensor 4,5,8,10,12,15, starter signal, and battery voltage signal according to the control program, and also inputs and calculates signals output from each sensor 4,5,8,10,12,15, and inputs and calculates signals output from each sensor 4,5,8,10,12,15, and inputs and calculates signals output from each sensor 4,5,8,10,12,15, A central processing unit (hereinafter simply referred to as CPU) performs processing for controlling the operation of a target, and 52 is a read-only memory (hereinafter simply referred to as CPU) in which data such as a map for calculating the control program and fuel injection amount is stored. , 53 is a random access memory (hereinafter simply referred to as RAM) in which data input to the electronic control unit 50 and data necessary for arithmetic control are temporarily read and written.
Reference numeral 4 denotes a backup random access memory (hereinafter simply referred to as backup RAM) 55 backed up by a battery 24 so as to retain data necessary for subsequent engine operation even when the key switch 25 is turned off.
denotes an input port (not shown), a waveform shaping circuit provided as necessary, a multiplexer that selectively outputs the output signals of multiple sensors to the CPU 51, and an A/D converter that converts analog signals to digital signals. , output boat, injector 16, igniter 23, etc.
The input/output section 56 is equipped with a drive circuit etc. that drives according to the control signal 50, and 56 represents a path line connecting each element such as the CPU 51, ROM 52, etc. and the input/output section 55, and through which data and control signals are sent. There is.

When the ignition switch is turned on, the microcomputer of the electronic control unit 50 starts executing the process shown in FIGS. 8 and 9 as the process according to the present invention.

FIG. 8 shows the main routine, in which the cooling water mTHW is changed to TH in step 101.
Determine whether it is greater than or equal to W2, and determine whether T I-I W is T I
- If it is less than IW2, in step 102 TH
W is the temperature obtained by subtracting the minute temperature α from TH'W2 (THW
2-α), and determine whether THW is smaller than (T).
If it is smaller than lW2-α), step 103 is passed and the process moves to the next step (not shown). When the simulated cooling water mTHW rises to THW2 or more, the determination result in step 101 is reversed to rYEsJ, and in step 104 it is determined whether or not flag F is rOJ.
Since is rOJ, the flag F is set to "1" in step 105, and then K is set to a constant value in step 106.

Here, K is K in the expression of the new lean air-fuel ratio correction coefficient KLEΔN, that is, KLEAN-KLEANB+K. In addition, KLEANB in the above formula
is the conventional KLEAN, that is, the value shown in Figure 2 before complete warm-up, and the engine speed N after complete warm-up.
KLEANNE as shown in Figure 3 defined by E.
KLEAN as shown in Figure 4 determined by
This is the same as the multiplication value with PM. After the correction IK is set to a constant value in this way, THW becomes (THW2-
While α) or above, no processing is performed on the correction IK in this main routine. On the other hand, = 10
= In the fixed time interval routine of FIG. 9, the correction 11K is decremented by a fixed value β at each fixed time interval in step 201, and in step 202 it is determined whether the correction 1iK after this decrement is "0" or more. It is determined whether or not the value is "0" or more, the process moves to a subsequent step (not shown), whereas if it is less than rOJ, the process proceeds to step 20.
After setting the correction amount K to "0" in step 3, the process moves to the subsequent step.

Therefore, when the correction amount K is set to a constant value in the main routine, thereafter, in the constant time processing routine,
The correction amount decreases from this fixed value by a fixed amount at fixed time intervals until it finally reaches 10.

On the other hand, if it is already fully warmed up when the engine starts to open,
Immediately, the correction amount K is set to a constant value, and thereafter this correction amount decreases by a constant amount at regular time intervals until it reaches "0".

Therefore, if the cooling water temperature THW rises after startup and the engine is completely warmed up, or if the engine is already fully warmed up at the time of startup, the fuel ratio will be on the rich side for a certain period from this point on, causing the engine to become sluggish. , can prevent shortness of breath, etc.

In the above embodiment, the correction amount K is decreased by a certain amount at certain time intervals, but the correction amount K may be set to "0" after a certain period of time has elapsed.

[Effects of the Invention] As explained above, the present invention sets the air-fuel ratio to the dry side for a predetermined period from when the cooling water temperature rises to a predetermined temperature indicating complete warm-up after the engine is started. Lean A/F feedback control before the aircraft to lean A/F after complete warm-up
It is possible to prevent engine sluggishness, sluggishness, etc. that tend to occur when shifting to F feedback control.

[Brief explanation of drawings]

Figures 1 to 4 are diagrams for explaining the problems of the conventional technology, Figure 5 is a claim correspondence diagram for clarifying the present invention, and Figures 6 to 9 are diagrams for explaining an embodiment of the present invention. 6 is an overall configuration diagram thereof, FIG. 7 is a block diagram schematically showing the internal configuration of the electronic control device, and FIGS. 8 and 9 are processing contents according to this embodiment, respectively. This is a flowchart 1- representing the following. Ml...Calculating means M2.1...Internal combustion engine M3...Setting means M4.50...Electronic control device M5.10...Lean sensor M6.16...Fuel injection valve agent Patent attorney Tsutomu Sadatsu and 1 other person -13- Figure 1 Figure 2 81wt tr-twz tt-tw

Claims (1)

[Scope of Claims] In an electronically controlled fuel injection system that operates an internal combustion engine at a target lean air-fuel ratio, the electronically controlled fuel injection device includes a calculation means for determining the fuel injection amount using an injection amount calculation formula including a lean air-fuel ratio correction coefficient, A correction amount that is set to a constant value larger than the value rOJ when the water temperature rises to a predetermined temperature indicating complete warm-up, and 'm I'OJ
The present invention is characterized in that means is provided for setting a value at which the lean air-fuel ratio correction coefficient is attenuated to 0 or immediately becomes "0" after a predetermined period of time, and the above-mentioned lean air-fuel ratio correction coefficient is added to this correction amount to obtain a new lean air-fuel ratio correction coefficient. Electronically controlled fuel injection device.