JPS62153541A - Fuel injection controller for internal combustion engine - Google Patents

Abstract

PURPOSE:To improve the drivability and develop the purifying capacity of catalyst by installing a fuel injection quantity reducing means for reducing the fuel jetted from a fuel injection value by a prescribed quantity for a prescribed time after the time point when a throttle valve passes through a prescribed opening position. CONSTITUTION:A fuel injection valve 7 is installed into the upstream side edge part of a throttle body 5, and a throttle valve 9 is arranged onto the downstream side of a fuel injection valve 7. An idle switch 2, 10 deg. switch 4, and a power switch 6 are installed onto the throttle valve 9. In the sharp deceleration from the perfect opened state of the throttle valve to the perfect closed state, the fuel injection quantity is reduced by 50% in comparison with that in the stationary traveling state, during the injection in four times from the time point when the opening of a throttle valve is set at 10 deg., and the fuel injection quantity is restored to the original state during 5sec. Thus, drivability can be improved and the purifying capacity of catalyst can be developed.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a fuel injection amount control device for an internal combustion engine, and in particular to a single point type fuel injection amount control device that reduces the fuel injection amount during deceleration. The present invention relates to a fuel injection control device for an internal combustion engine.

[Prior art] Conventionally, the basic fuel injection amount is determined based on the intake pipe pressure (absolute pressure) as the engine load and the engine speed, and the fuel injection amount is determined by correcting this basic fuel injection amount based on intake air temperature, etc. 2. Description of the Related Art There is known a fuel injection prohibition 0'Il device that controls a fuel injection valve to inject fuel in an amount corresponding to the fuel injection amount.

In such a fuel injection amount control device, the intake pipe pressure decreases during deceleration, fuel adhering to the inner wall of the intake manifold evaporates, and the air-fuel ratio becomes rich at the beginning of deceleration, deteriorating drivability and exhaust emissions.

For this reason, conventionally, the rate of change ΔPM of intake pipe pressure and the rate of change ΔTA of throttle opening are detected and the weight loss coefficients FTCPM and FTCTA which change as shown in FIG. 7(B) are calculated. Fuel injection using! 11: (Japanese Unexamined Patent Publication No. 58-48725, Japanese Unexamined Patent Publication No. 8-623'25).

[Problems to be Solved by the Invention] However, in the deceleration reduction using the conventional reduction coefficient FTCPM, the pressure sensor output is reduced by the rate of change of the intake pipe pressure which deteriorates the response through a filter circuit etc. Therefore, the actual timing of weight reduction is 100 to 150 m from the engine's yellowing time.
There is a delay of 5 ec, and in the later stages of deceleration, overshoot of the intake pipe pressure through the filter circuit etc. occurs, resulting in a large amount of fuel loss. For this reason, as shown in FIG. 7(A), the air-fuel ratio A/F becomes excessively rich in the early stages of deceleration, and the air-fuel ratio becomes lean in the latter stages of deceleration, resulting in poor drivability. There was a problem. The above deterioration in drivability, etc. is particularly caused by installing one fuel injector on the upstream side of the throttle valve 221. When the fuel injection amount control device of the single point injection type is ≧1, the distance from the fuel injection position to the combustion chamber is long, so that the labeling on the inner wall of the intake manifold increases and becomes noticeable. In addition, even in the case of sudden changes such as a shift change, the drivability deteriorates due to the above-mentioned timing d etc. WJ7. It appears in

On the other hand, when reducing the amount by FTCTA, a fuel cut is executed at the initial stage when the throttle valve opening changes, and the amount of i- is gradually reduced after the middle stage of deceleration. In a single-point injection type fuel injection amount control device, the distance from the fuel injection position to the combustion chamber is determined by the distance between the fuel injection position and the combustion chamber.
' As shown in Fig. 7 (C), M becomes small near full throttle, so even if the weight is reduced at the beginning of deceleration, there is not much effect, and as shown in Fig. 7 [N (A), There is a problem in that the air-fuel ratio becomes rich due to an over-short in the intake pipe pressure.

The above-mentioned problem occurs not only in single-point injection type fuel injection amount control devices, but also in ordinary fuel injection amount control devices that include a fuel injection valve for each cylinder.

[Means for Solving the Problem] The present invention has been made to solve the above-mentioned problem in winter, and is capable of injecting a predetermined amount of fuel based on the engine load and engine speed by controlling the fuel injection valve. a throttle valve detecting means for detecting whether or not the throttle valve has rotated in the closing direction and passed through a predetermined opening position on the fully closed side of the throttle valve; and fuel injection amount reduction means for reducing the amount of fuel injected from the fuel injection means by a predetermined amount for a predetermined period from the time when it is detected that the fuel injection means has passed through the fuel injection means.

[Operation] According to the present invention, the deceleration range H, -H of the fuel injection amount control device
- is executed from the time when the throttle valve rotates in the closing direction and passes a predetermined opening position (for example, 100) on the fully closed side of the throttle valve. That is, FIG. 7(B) (shaded area) shows an example of the single point injection method.
As shown in FIG. 7(C), one row of deceleration reduction is performed at an early stage when the intake pipe pressure PM decreases (near the engine request timing). The change in air-fuel ratio at this time is as shown in FIG. 7(A), which shows an example.

[Effects of the Invention] According to the present invention, fuel injection ↑- (deceleration reduction of the control device can be executed from around the engine request timing without using an expensive linear throttle sensor, etc.). This improves drivability by preventing a large change in richness and tone, and improves drivability.
It has the effect of being able to fully exhibit the cure property 1 luster.

[Embodiments of the invention] Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 2 schematically shows a single-point injection type automobile internal combustion engine equipped with a fuel injection amount control device according to an embodiment of the present invention. The air cleaner 1 is connected to a throttle body 5 via an inlet pipe 3. One fuel injection valve 7 is arranged at the upstream end of the throttle body 5, and an accelerator pedal (not shown) is arranged downstream of the fuel injection valve.
A throttle valve 9 is arranged to adjust the intake air flow in conjunction with the IF, and an intake pipe pressure sensor 11 is attached to the downstream side of the throttle valve 9 to measure the absolute pressure at that part. The above-mentioned throttle valve 9 includes an idle switch 2 that turns on when the throttle valve is in the idle position (fully open state), a 10° switch 4 that turns on when the throttle opening is 10 degrees or more and turns off when the throttle opening is less than 10 degrees, and a 10° switch 4 that turns on when the throttle opening is 10 degrees or more and turns off when the throttle opening is less than 10 degrees. A power switch 6 that is turned on is installed so as to be turned on and off in conjunction with a throttle valve 9. These switches 2
The throttle body 5, whose on/off state at 4.6° is shown in FIG. 6, is connected to the combustion chamber 27 of the engine via an intake manifold 13 having branch pipes connected to each cylinder of the engine. Intake manifold 13
A riser portion 17 is provided at the bottom 13A before the branch, through which engine cooling water is circulated to heat the air-fuel mixture.

A combustion chamber 27 is formed in the engine body 19 by a piston 21, a cylinder 23, and a cylinder head.
The air-fuel mixture sucked into the combustion chamber 27 via the intake valve 29 is ignited by the spark plug 31 . A water jacket 33 is formed around the cylinder 23, and engine cooling water is circulated through the water jacket 33 to cool parts including the cylinder 23. An engine coolant temperature sensor 37 is provided on the outer periphery of the cylinder block 35 to measure the temperature of the engine coolant in the water jacket 33.
is installed.

The exhaust hole (not shown) of the cylinder head 25 is connected to an exhaust manifold 39, and an 02 sensor 41 for measuring the residual oxygen concentration in the exhaust gas is installed downstream of the exhaust manifold 3'9. This exhaust manifold 39 is connected to four exhaust pipes via a catalyst device filled with a three-way catalyst.

The distributor 55 includes a signal rotor fixed to the distributor shaft.

A cylinder discrimination sensor 57 and an engine rotation speed sensor 59, each consisting of a pickup fixed to the distributor housing, are attached. In the case of a six-cylinder engine, the cylinder discrimination sensor 57 outputs a signal every 720° CA, and the engine rotation speed sensor 59 outputs a signal every 30'CA.

The control circuit 61 composed of a microcomputer etc.
As shown in Figure 3, read-only memory (RO
M) 62, micro processing unit (MPU)
) 60, random access memory (RAM) 6
4. Input/Output Capo Toro 8° Input/Output Capo) 70. Capo) 7
2.74 and a bus 8 such as a data bus and a control path that connect these. The input/output capotro 8 has buffers 82, 84 . multiplexer 80
The intake pipe pressure sensor 11 and the engine coolant temperature sensor 37 are connected via an analog-to-digital (A/D) converter 78, respectively. The 02 sensor 41 is connected to the input port door 0 via a buffer 86 and a comparator 88, and the cylinder discrimination sensor 5 is connected to the input port door 0 via a waveform shaping circuit 90.
7 and engine rotation speed sensor 59 are connected,
The idle switch 2, 10' switch 4 and the power switch 6 are directly connected.

The output port door 2 is connected to the igniter 42 via the drive circuit 92.
It is connected to the. Furthermore, the output port door 4 is connected to the drive circuit s.
+4 to the fuel injection valve 7. In addition,
98 is a clock, and 100 is a timer.

Next, the control routine of this embodiment will be explained. The following routine describes the reduction in speed when the throttle valve is suddenly decelerated from a fully open state to a fully closed state. FIG. 4 shows a power flag setting routine that is executed at predetermined intervals. In step 102, it is determined whether or not the power switch 6 is on. If the power switch is on, the flag XPOW is set in step 104. Set.

Then, in step 106, the count value CN is set to 4, and the timer TFTI is set to 5.

FIG. 5 shows an interrupt routine executed by an interrupt every 1 sec. In step 110, the timer T
It is determined whether the value of FTI is 0 or not, and if this determination is negative, the value of timer TFTI is incremented by one in step 112.

FIG. 1 shows a fuel injection amount calculation routine that is executed every engine rotation. In step 116, a basic fuel injection amount TP is calculated based on the intake pipe pressure PM and the engine rotation speed NE. Basic fuel injection amount] Pt1 - Calculate the fuel injection jJ T A U by correcting it according to the engine cooling water temperature, etc. In the 0th step 118, r1 is determined whether the flag xpow is set, and the flag XPOW is set. If so, in step 120 the 10' switch 4 is turned on.
Determine whether or not it is turned off. When the 10' switch is off, the timer TFT is turned off in step 122.
It is determined whether the value of I is not O. When the determination in step 122 is affirmative, it is determined in step 124 whether the count value CN is O or not. When the count value CN is not O, that is, when the throttle valve is decelerated from the fully open state, the value of the reduction coefficient is set to 0.5 in step 126, and the reduction coefficient K is set to the fuel injection amount TAU in step 128.
The reduced fuel injection amount TAU is calculated by multiplying by .

Then, in the next step 130, the count value CN is incremented by one day. The KARANTOI direct CN is set to 4 when the power switch 6 is turned on, and is decremented by 1 in step 130, and the reduction coefficient K is set to 0.5, so the fuel injection amount is 50% in the 4 injection at the beginning of deceleration. The weight is reduced.

On the other hand, when it is determined that the count value CN is O in step 124, the value of the weight loss coefficient is increased by 0.1 in step 132, and the weight loss coefficient K is increased by 1 in step 134.
Determine whether or not the above is true. When the reduction coefficient K is 1 or more, the flag xpow is reset at stitch 136. When the reduction coefficient K is less than 1, the fuel injection amount is multiplied by the reduction coefficient K in step 138 to obtain the fuel injection amount TAU.

As a result of the above, during sudden deceleration from the throttle valve fully open state to the fully closed state, the fuel injection amount is 50% of the steady running state for 4 injections from the time when the throttle valve opening reaches lOo.
The reduction coefficient K is gradually increased over 5 seconds, and the fuel injection amount is gradually returned to its original state. Further, FIG. 7 shows changes in the reduction coefficient K and the air-fuel ratio when controlled as described above.

Note that the above-mentioned weight loss ratio and number of injections for weight loss injection are determined through experiments for each engine.

[Brief explanation of drawings]

FIG. 1 is a flowchart showing a fuel injection routine according to an embodiment of the present invention, FIG. 2 is a schematic diagram showing an engine equipped with the fuel injection amount control device according to the above embodiment, and FIG. FIG. 4 is a flow chart showing the flag set routine of the above embodiment, FIG. 5 is a flow chart showing the 1 sec routine of the above embodiment, and FIG. 6 is a flow chart showing the details of the control circuit of the above embodiment. FIG. 7 is a diagram showing changes in the air-fuel ratio, reduction coefficient, etc. 40-〇〇Switch 61・Power switch 11・・Pressure sensor. Figure 1 Figure 2 Figure 4 Figure 5゜Figure 6

Claims (1)

[Claims] (1) A fuel injection means that injects a predetermined amount of fuel based on the engine load and engine speed by controlling the fuel injection valve, and a throttle valve that rotates in the closing direction to the fully closed side of the throttle valve. throttle valve detection means for detecting whether or not the throttle valve has passed through a predetermined opening position; and a fuel injection means for injecting fuel for a predetermined period from the time when it is detected that the throttle valve has passed through the predetermined opening position. A fuel injection amount control device for an internal combustion engine, including a fuel injection amount reducing means for reducing fuel by a predetermined amount.