JPS6155330A - Fuel injection quantity controller for internal-combustion engine - Google Patents

Abstract

PURPOSE:To prevent the smoldering of a spark plug and an engine stall both from occurring, by increasing a fuel quantity only at the specified time in time of fuel-cut resetting during engine warming up. CONSTITUTION:A fundamental fuel injection quantity is calculated by a fundamental fuel injection quantity operational device according to the specified driving state parameter, and a fundamental injection quantity in time of warming up is compensated with a warm-up increment value f0 calculated according to engine cooling water temperature THW. When a throttle valve opens fully and an engine speed becomes below the fuel-cut resetting engine speed, the warm-up increment value f0 is increase as much as a fixed rate in addition. With this constitution, the engine speed in time of fuel-cut resetting at the engine warm-up is prevented from dropping and, what is more, the smoldering of a spark plug is also preventable.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a fuel injection amount control device for an internal combustion engine during warm-up operation.

BACKGROUND OF THE INVENTION In general, fuel cut is a measure to improve fuel efficiency by stopping fuel injection during deceleration, etc., and fuel cut is controlled by the opening degree of the throttle valve, the rotational speed of the engine, etc. For example, a fuel cut is performed when the throttle valve is fully closed and the engine rotation speed is higher than the fuel cut rotation speed, and when the throttle valve is not fully closed or the throttle valve is fully closed, the engine rotation speed returns to fuel cut. Cancel fuel cut when the rotation speed is below. In this case, the fuel cut rotation speed is higher than the fuel cut return rotation speed, and both are set according to engine operating state parameters, such as cooling water temperature.

In an internal combustion engine having the above fuel cut system,
If a fuel cut return is performed from a fuel cut state during warm-up, a larger increase in fuel consumption is required than during non-warm-up. Therefore,
Conventionally, the amount was simply increased during warm-up.

Problems to be Solved by the Invention However, as with the conventional method described above (if you increase the amount of fuel in the Hayabusa during warm-up, the ignition plug is likely to be overpowered,
Therefore, there was a problem in that the engine stalled after racing.

Means for Solving the Problems In view of the above-mentioned problems, an object of the present invention is to provide a plug that does not deteriorate the smoldering resistance of the plug by supplying 1 fuel for only a predetermined period of time when returning from fuel cut during warm-up. The main purpose is to prevent engine stalling after racing, and the means for this purpose is shown in FIG.

In FIG. 1, the basic injection amount calculation means calculates the basic injection size τp according to the number and the predetermined operating condition parameters of the internal combustion engine. ′? &The engine increase value calculation means also uses the engine cooling water temperature TH.
A warm-up increase value fO is calculated according to W.

The fuel cut return state determination means determines a change from the fuel power/throat state force 1 of the engine to the fuel cut return state in accordance with predetermined engine operating parameters. As a result of this, the timer means moves the predetermined distance between G and A on the A side when returning from fuel cut.

Further, the throttle valve fully closed determining means determines whether or not the throttle valve of the engine is fully closed. The fuel increase means further increases the warm-up increase value fo by a certain percentage when the throttle valve is fully closed and the timer means is measuring a predetermined time. The final injection amount calculation means corrects the basic injection amount τ0 by the warm-up increase value fo to calculate the final injection amount.

At the time of fuel cut natural recovery during warm-up (LL = "1"),
The warm-up amount is further increased only for a predetermined period of time.

Embodiment FIG. 2 is an overall schematic diagram showing an embodiment of a fuel injection amount control device for an internal combustion engine according to the present invention. In FIG. 2, an air flow meter 3 is provided in an intake passage 2 of an engine body 1. As shown in FIG. The air flow meter 3 directly measures the intake air amount, has a built-in potentiometer, and generates an analog voltage output signal proportional to the intake air amount. This output signal is output from the multiplexer built-in A/D of the control circuit 10.
It is supplied to converter 101. Further, an idle switch 5 is provided on the shaft G of the throttle valve 4 provided in the intake passage 2 of the engine body 1 to detect whether the throttle valve 4 is in a fully closed state. The output signal LL of the idle switch 5 is input to the input/output interface 1 of the control circuit 10.
02. The distributor 6 has a crank angle sensor 7 whose shaft generates a reference position detection knob signal every 720 degrees in terms of crank angle, and a crank angle sensor 7 which generates a reference position detection knob signal every 30'' in terms of crank angle. A crank angle sensor 8 is provided which generates a pulse signal.The crank angle sensor 7.8 output pulse signals are supplied to an input/output interface 102 of a control circuit 10. is CPU103
is supplied to the interrupt pin.

Further, the intake passage 2 is provided with a fuel injection valve 9 for supplying pressurized fuel from a fuel supply system to the intake port for each cylinder.

In addition, a water temperature sensor 1 is installed in the water jacket of the cylinder protector of the engine body 1 to detect the temperature of the cooling water.
1 is provided. The water temperature sensor 11 indicates the cooling water temperature T.
Generates analog voltage electrical signals according to HW.

The control circuit 10 is configured, for example, as a microcombination system, and includes an A/D converter 101, an input/output interface 102, and a CPU 103 as well as 110M104, R
A? 1105 etc. are provided.

Further, in the control circuit 10, a down counter 106,
Flip-flop 107 and drive circuit 108 are for controlling fuel injection valve 9. That is, in the routine described later, when the fuel injection amount τ is calculated, the fuel injection amount τ is preset in the down counter 106 and the flip-flop 107 is also set. As a result, the drive circuit 108 starts energizing the fuel injection valve 9.

On the other hand, the down counter 106 counts the clock signal (not shown) and finally its carrier terminal is
When the level becomes II, the flip-flop 107 is reset and the drive circuit 108 stops energizing the fuel injection valve 9. In other words, the fuel injection valve 9 is energized by the above-mentioned fuel injection amount τ, so that an amount of fuel corresponding to the fuel injection amount τ is sent into the combustion chamber of the engine body 1.

Note that the interrupt generation of the CPU 103 is caused by the A/D converter 10.
1, the human output interface 102
For example, when the pulse signal from the crank angle sensor 8 is received.

The intake air amount data Q of the air flow meter 3 and the water temperature data THW of the water temperature sensor 11 are taken in by an A/D conversion routine executed at predetermined time intervals and stored in the RAM/105.
is stored in a predetermined area. That is, data Q and THW in RAM 105 are updated at predetermined time intervals. The rotational speed data Ne of the car is from the crank angle sensor 8-3.
It is calculated by an interrupt for each 0'CA and stored in a predetermined area of the RAM 105.

The operation of the control circuit shown in FIG. 2 will be explained below.

FIG. 3 shows a fuel cut setting routine, which is configured as a part of the main routine. That is, this routine is for setting the fuel cut flag F as shown in FIG. In FIG. 4, Nc indicates the fuel cut rotation speed, and NR indicates the fuel cut return rotation speed, both of which are updated according to the engine cooling water temperature THW.

In step 301, the output signal L of the idle switch 5 is
It is determined whether L is II I II, that is, whether it is in an idle state. Step 30 if non-idle
5; on the other hand, if it is idle, proceed to step 30
Proceed to step 2. In step 302, the rotation speed Ne is read from the RAM 105 and compared with the fuel cut rotation speed Nc, and in step 303, it is compared with the fuel cut return rotation speed NR. As a result, when Ne≧Nc, step 3
At step 04, the flag F is set to IT I II, and when Ne≦NR, the process proceeds to step 305. When NR<Ne<Nc, flag F is held at its previous state.

In step 305, it is determined whether or not the flag F=1'1'' is set.In other words, if F=u lIf, it means that the current fuel cut state has changed to the fuel cut return state.Therefore, in step 305 When it is determined that F=para''', the flag F is set to 1 in step 306.
10 II, and in step 307, the counter C is set to 500 as an initial value.

Note that the counter C is incremented by -1 in the 4IIls routine shown in FIG. 5 and held at 0. Therefore, after setting the initial value 500, the counter C is set for 2 s.
(-4m5X500) will be measured.

Further, in step 305 of FIG. 3, if the result is FO'', the process directly proceeds to step 308, and this routine ends.

In this way, when the fuel cut state changes to the fuel cut return state, the counter C serving as a timer means is counted and the measurement of a predetermined time (2 s) starts at 1 m.

FIG. 6 shows a fuel injection amount calculation routine, which is executed at every predetermined crank angle, for example, every 180° CA (=720° CA/4 cylinders). In step 601, it is determined whether the fuel cant flag F is II OII. F=IT I
If it is II, the process proceeds to step 609, and the calculation of the fuel injection amount is not performed. In other words, execute a fuel cut. F
If =TIOII, the process proceeds to step 602 and subsequent steps.

In step 602, the intake air amount data Q and rotational speed data Ne are read from the RAM 105, and the basic injection amount τ
0 is calculated and stored in the RAM 105.

In step 603, water temperature data T is stored in RAM/105.
The warm-up increase value fo is calculated by interpolation using the one-dimensional map stored in the ROM 104 by reading the HW, and
Store in.

In step 604, it is determined whether the counter C is 0 or more. That is, it is determined whether or not the counter C is measuring a predetermined time (2 seconds). Further, in step 605, it is determined whether the output LL of the idle switch 5 is II II II. As a result, only when the counter C is measuring the above-mentioned time and is in the idle state G (LL="1"), the process advances to step 606 and the warm-up increase value r is determined.

Further increase the amount. Otherwise, proceed directly to step 607.

In step 607, the final injection amount τ is calculated.

In other words, τ←τo (1+fo) is calculated, and in step 608, as described above, CPt
1103 inputs the injection amount τ to the down counter 106 and inputs the flip-flop 107, and the routine shown in FIG. 6 ends at the steering knob 609.

Note that in step 607, the injection amount τ may be corrected based on other operating state parameters as necessary.

In this way, after the fuel cut is restored, if the engine is in an idling state, the fuel increase force is applied only for a predetermined period of time.

Effects of the Invention FIGS. 7 and 8 are graphs for explaining the effects of the present invention in comparison with the conventional type. According to the present invention, FIG.
), when the fuel cut state is entered at time t1, the rotational speed Ne decreases, and the fuel cut return is performed at time t2. At this time, as shown in Figure 7 (B),
Since the fuel amount is increased only for a predetermined period of time (2S), there is no drop in the rotational speed Ne, and therefore, engine stall can be prevented.Furthermore, since the fuel amount increase does not last, there is no smoldering of the fuel.

On the other hand, as shown in FIG. 8(B), if the amount of fuel is not increased when returning from fuel cut, the rotational speed Ne will drop significantly during warm-up, as shown in FIG. 8(A). In the worst case, this will lead to engine stall. In order to prevent this, conventionally, the amount of fuel is increased continuously, and although this can prevent the rotational speed Ne from decreasing, the smoldering of the spark plug may still cause a misfire, leading to an engine stall.

As described above, according to the present invention, a drop in rotational speed is prevented and the smoldering resistance of the spark plug is not deteriorated, so that engine stall after racing can be prevented.

[Brief explanation of drawings]

FIG. 1 is an overall block diagram for explaining the present invention in detail, FIG. 2 is an overall schematic diagram showing an embodiment of a fuel injection amount control device for an internal combustion engine according to the present invention, FIGS. 3 and 5 , FIG. 6 is a flowchart for explaining the operation of the control circuit in FIG. 2, FIG. 4 is a diagram showing the characteristics of flag F in FIG. 3, and FIG.
FIG. 8 is a graph explaining the present invention in detail. 1...i function, 3...air flow meter, 4...throttle valve, 5...idle switch, 9...fuel injection valve, 10...control circuit,
11...Water temperature sensor.

Claims (1)

[Claims] 1. Basic injection amount calculation means for calculating a basic injection amount according to predetermined operating state parameters of the internal combustion engine; warm-up increase value calculation means for calculating a warm-up increase value according to the cooling water temperature of the engine;
A fuel cut return determination means for determining a change in the engine from a fuel cut state to a fuel cut return state according to a predetermined operating state parameter of the engine; a timer means for measuring a predetermined time during the fuel cut return; Throttle valve fully closed determination means for determining whether the throttle valve is fully closed;
fuel increasing means for further increasing the warm-up increase value by a certain percentage when the throttle valve is fully closed and the timer means is measuring the predetermined time; and correcting the basic injection amount by the warm-up increase value. A fuel injection amount control device for an internal combustion engine, comprising a final injection amount calculation means for calculating a final injection amount.