JPS58200044A - Fuel injection controller of internal-combustion engine - Google Patents

Abstract

PURPOSE:To improve the starting property of the titled device by increasing the injection quantity of the fuel for the second time and thereafter more than the injection quantity for the first time at the starting time. CONSTITUTION:Whether an engine is in a starting state or not is discriminated in a step 204. If the engine is in a starting state, whether the injection was carried out or not is discriminated. In a case where the injection has not been carried out once or more at the starting time, the injection pulse length is set at a step 206. In a case where the injection has been carried out once or more, a correction operation depending upon the water temperature is carried out in a step 207, and thereafter the injection pulse length is set in a step 208. In the injection at the second time and thereafter, the pulse length is made larger than in the injection for the first time upon starting. By these procedures, the starting property can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuel injection control device for an internal combustion engine.

Conventionally, fuel injection at the time of starting an internal combustion engine is performed in synchronization with the rotation speed of IalrJkJ or at a fixed cycle.
In addition, the injection/gurusu flow book used values that were mapped according to the cooling water temperature so that they were large when the temperature was low and small when the temperature was high. However, with the fuel injection method of 1st grade, there was a problem in the startability of the hP3 fuel engine when it was warmed up. In other words, when starting after warming up, there are cases where there is fuel remaining in the intake manifold as usual, and cases where there is no fuel at all in the intake manifold after the key switch has been turned off for a long time. Usually, the fuel injection amount is set based on the former, so in the latter case, there is a shortage of fuel injection lids, resulting in poor startability.

The present invention has been made in order to eliminate the above-mentioned conventional drawbacks, and provides a fuel injection control device for an internal combustion engine that can improve the starting characteristics of an internal combustion engine when warmed up. With the goal.

Embodiments of the present invention will be explained below with reference to the drawings.

In FIG. 1, 100 is a control circuit that calculates the fuel injection amount based on information obtained from the internal combustion engine and drives the injector (fuel injector) 4, and the control circuit 100 is a CPU l
0I, interrupt processing section 102, digital input processing section 10
3. Analog input processing section 104, RAMI O5, RO
M 106 , a timer 107 and an injector drive circuit 108 . CPU 01 calculates the fuel injection amount, interrupt processing 1i102Fi Il from rotation speed detector 1
! The rotation speed detection signal is waveform-shaped and an interrupt signal is sent to the CPU 01 in synchronization with the rotation speed. A digital input processing section 103 receives a digital signal from a digital signal generating section 2 such as a start switch or an idle switch, adjusts the level of this signal 7, and transmits the signal to the CPU 01. The analog input processing unit 104 consists of an analog multi-solexer and an AD converter, and sequentially converts analog signals from the analog signal generator 3 such as a battery voltage sensor, a cooling water temperature sensor, an intake pipe negative pressure sensor, and an h sensor into AD converters. Transmit signal to CPUI 01.CPU
101 learns the shape of the internal combustion engine from these input signals,
Calculate fuel injection lid. The RAM 105ij stores data, and the ROM 106t;j stores programs. The timer 107 also serves as a timer for internal calculation of the CPU 01 of the period meter 1111 and a timer for outputting the drive cycle and pulse width of the injector 4. Further, the injector drive circuit 108 receives the output of the timer 107 and drives the injector 4.
to drive.

Next, the operation of CPUl0I will be explained with reference to the chart 70 shown in FIG. The main process of Stella 7'' 200 is a routine that determines the injection pulse width.
201 performs initialization. In step 202, it is determined whether or not the engine is stopped, and if the engine is stopped, step f203
Stops fuel injection and returns to step f202. If the engine is not in the stop state 1, the process proceeds to Stella f204, where it is determined whether or not the engine Ia is in the starting state. This is normally determined by the engine 1 revolution signal or start signal. If it is in the starting state, the process proceeds to step 205, where it is determined whether or not injection has been performed. If no injection has been performed yet, a predetermined injection pulse width is set in Stella f206, and the process returns to step f202 again. . If it is confirmed in step 205 that injection was performed more than once during startup, a correction calculation depending on the water temperature is performed in step 207, and then the injection pulse width is set in step 208, and the process returns to step f202. . If it is determined that the STELLA F204 is not in a starting state, that is, in a normal operating state, the basic injection amount is calculated in step 209, various correction calculations are performed in step 210, and the injection pulse width is set in step 211. Return to step 202. Each step 206,2
08,211 is set at step 206.
In step 211, the size of rice is also reduced. Set A? The pulse width is used when the injector 4 is driven in an interrupt processing routine according to a rotational speed detection signal from the rotational speed detector 1 or within a fixed period interrupt processing routine.

In the above embodiment, the noculus at is larger in the second and subsequent injections at startup, that is, the number of fuel injection lids is increased, compared to the injection during normal operation, and the number of fuel injections 1 is further increased in the first injection at startup. It improves starting performance when more fuel is required, and increases the amount of first injection at startup, especially when there is little or no residual fuel in the intake manifold, such as during warm-up. This allows for a smooth start.

In the above embodiment, the width of the first injection/4' pulse at the time of startup is set to 2[il!] at the time of startup. Although the injection pulse width was made larger than the injection pulse width after the first injection, the parent pulse width (up to about the third injection at startup) may be made larger from then on. It's really good for getting big.

As described above, in the present invention, the initial fuel injection amount is increased especially when starting the internal combustion engine, which requires a larger amount of fuel, and not only during normal starting but also during starting during warm-up. Since fuel is sufficiently supplied, startability can be improved.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a fuel injection control device for an internal combustion engine according to the present invention, and FIG. 2 is a flowchart of a CPU in the fuel injection control device for an internal combustion engine according to the present invention. DESCRIPTION OF SYMBOLS 1... (b) Rotation number generator, 2... Digital signal generation part, 3... Analog signal generation part, 4... Injector, 100... Control circuit, 101... CPU, 1
02... Interrupt processing unit, 103... Digital input processing unit, 104... Analog input processing unit, 105...
・RAM. 106...ROM, 107...Timer, 108...
・Injector drive side circuit. Agent Shin Kuzuno - Figure 1 3o.

Claims (1)

[Claims] (1) In a fuel injection control system for an internal combustion engine that opens the fuel injection lid based on information obtained from the internal combustion engine, the initial fuel injection lid is opened at the time of starting the internal combustion engine, and the fuel injection lid is A fuel injection control device for an internal combustion engine characterized by having more than an injection lid.