JPS62284941A - Injecting method for fuel injection type internal combustion engine - Google Patents

Abstract

PURPOSE:To promote the atomization of fuel and improve the starting property particularly in the cold state of an engine by dividing a required fuel injection quantity in one injection period of a fuel injection type internal combustion engine into plural times and intermittently carrying out fuel injections. CONSTITUTION:During the operation of an internal combustion engine, a control circuit 10 receives the output signals of an air quantity sensor 14, a throttle valve opening sensor 18, a water temp. sensor 20, an O2 sensor 22, etc., and obtains a required fuel injection time corresponding to a required fuel injection quantity in one injection period of an engine 2 for each ignition timing in accordance with change in an engine operating condition, to control a fuel injection valve 8. In this case, when the engine 2 is judged under a starting operation by the control circuit 10, divided fuel injection time and fuel injection stopping time obtained by dividing a required fuel injection time in one injection period are alternately set and an injection signal is outputted. Thereby, fuel is prevented form flowing in a liquid state, promoting the atomization of the fuel.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an injection method for a fuel-injected internal combustion engine, and particularly to a method for promoting atomization of fuel in a fuel-injected internal combustion engine to facilitate mixing with air. The present invention relates to an injection method for a fuel-injected internal combustion engine that can improve starting performance, and in particular improve startability.

[Conventional technology]

In a fuel injection type internal combustion engine, the amount of fuel injection required by the engine is set according to changes in engine load, engine speed, cooling water temperature, intake air amount, etc.

For example, when starting a cold internal combustion engine,
As disclosed in Japanese Patent Laid-open No. 3831 and Japanese Patent Application Laid-Open No. 58-214625, the required fuel injection time required by the engine is set longer in response to changes in engine temperature and cooling water temperature, and an increased amount of fuel is injected.

[Problem that the invention seeks to solve]

However, in these systems, fuel is continuously injected within the required fuel injection time, so the fuel flows in liquid form, especially during cold engine startup. For this reason, the fuel is difficult to atomize and is not sufficiently mixed with air, resulting in poor starting performance.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide an injection method for a fuel-injected internal combustion engine that promotes atomization of the fuel in the engine, improves its mixing with air, and improves starting performance in particular. .

[Means for solving problems]

In order to achieve this object, the present invention is characterized in that the required fuel injection amount within one injection period of a fuel-injected internal combustion engine is divided into a plurality of times and fuel is injected intermittently.

[Effect]

According to the configuration of the present invention, the required fuel injection amount within one injection period of the fuel injection internal combustion engine is divided into a plurality of times and fuel is injected intermittently. In this way, the required fuel injection amount within one injection period is divided into multiple periods and injected intermittently, so the fuel does not flow in liquid form, promoting atomization and improving mixing with air. do.

〔Example〕

Next, embodiments of the present invention will be described in detail based on the drawings.

1 to 4 show embodiments of this invention. In FIG. 1, 2 is a fuel injection type internal combustion engine, 4 is an intake passage, 6 is an exhaust passage, 8 is a fuel injection valve, and 10 is a control circuit.

The fuel injection valve 8 attached to the intake passage 4 is connected to a control circuit l.
The operation is controlled by O. The control circuit 10 includes an air amount sensor 14 provided in the intake passage 4 downstream of the air cleaner 12, an opening sensor 18 that detects the opening of the intake throttle valve 16,
A coolant temperature sensor 2 that detects the coolant temperature of the internal combustion engine 2
0 and the 02 sensor 22 provided in the exhaust passage 6,
Further, an ignition coil 24 is connected to which an ignition signal for setting the injection timing is input. Based on the signals inputted from these various sensors 14 to 24, the control circuit 10 controls the operation of the internal combustion engine 2 at every ignition timing S as the injection timing based on the ignition signal, as shown in FIG. 2(c). An injection signal having a required fuel injection time To corresponding to the required fuel injection amount within the injection period is output, and the operation of the injection valve 8 is controlled to inject fuel into the internal combustion engine 2.

At the time of starting such a fuel injection type internal combustion engine 2, the required fuel injection time is set long to inject an increased amount of fuel.
Conventionally, the required fuel injection time To
Since fuel is continuously injected into the engine, the fuel flows in liquid form, especially when starting a cold engine. For this reason, the fuel is difficult to atomize and cannot be sufficiently mixed with air, resulting in a disadvantage that starting performance is deteriorated.

Therefore, in the present invention, the starter switch 26 is connected to the control circuit 10, and the starter switch signal is input as a signal for determining when the engine is started. In addition to this, an engine speed signal from an engine speed sensor (not shown) can be input as the signal for detecting when the engine starts.
It is also possible to detect when the engine is started by inputting a combination of the starter switch signal and the engine rotational speed signal.

When the starter switch 26 manually inputs the starter inch signal at the time of starting the internal combustion engine 2, the control circuit 10 controls one injection period T within the ignition timing interval S as shown in FIG. 2(a).
s, the divided fuel injection time T1 obtained by dividing the required fuel injection time TO as shown in FIG. 2(b) and FIG. control the operation and inject fuel.

Here, the internal combustion engine 2 is a 4-stroke internal combustion engine,
The engine speed is N, the number of cylinders is n, and the required fuel injection time is To.
Then, the above-mentioned one injection period Ts is given.

Fuel is injected while alternating with a fuel injection pause time T2, which is obtained by adding a divided fuel injection time T1 obtained by dividing the required fuel injection time To.

Note that as the engine speed N increases, one injection period Ts becomes relatively short, so the divided fuel injection time 71 obtained by dividing the required fuel injection time To is determined by the engine speed N as shown in FIG.
becomes shorter in inverse proportion to

By injecting fuel by repeating the divided fuel injection time T1 obtained by dividing the required fuel injection time To by alternating with the fuel injection stop time T2, one amount of the internal combustion engine 2 is divided into multiple times and intermittently injected. It turns out.

Therefore, it is possible to prevent the fuel from flowing into the internal combustion engine in liquid form, promote atomization, and improve mixing with air, thereby improving the startability of the internal combustion engine 2, especially in cold air. .

〔Effect of the invention〕

As described above, according to the present invention, the required fuel injection amount within one injection period of a fuel-injected internal combustion engine is divided into multiple times and intermittently injected, thereby reducing the required fuel injection amount within one injection period. Since fuel is injected by dividing the injection amount,
The fuel does not flow in liquid form, promotes atomization, improves mixing with air, and improves starting performance of the internal combustion engine, especially in cold air.

[Brief explanation of the drawing]

Figures 1 to 4 show embodiments of the present invention, Figure 1 is a schematic sectional view of a fuel injection internal combustion engine to which the invention is applied, Figure 2 is a timing chart, and Figure 3 is Figure 2(b). FIG. 4 is a partially enlarged view showing the relationship between the divided fuel injection time and the engine speed. In the figure, 2 is a fuel injection type internal combustion engine, 4 is an intake passage, 6 is an exhaust passage, 8 is a fuel injection valve, 10 is a control circuit, 1
4 is an air amount sensor 14, 16 is an intake throttle valve, 20 is a cooling water temperature sensor 20, and 26 is a starter switch 26.

Claims (1)

[Scope of Claims] 1. An injection method for a fuel injection internal combustion engine, characterized in that the required fuel injection amount within one injection period of the fuel injection internal combustion engine is divided into a plurality of times and fuel is injected intermittently. . 2. The fuel injection internal combustion engine is a 4-cycle internal combustion engine, the engine speed is N, the number of cylinders is n, the required fuel injection time is T_0, and the above within one injection period 120/(N・n). Divided fuel injection time T_1 obtained by dividing the required fuel injection time T_0
(T_1+T_2)T_0/T_1≦120/(N・n
), the fuel injection is performed alternately with the fuel injection stop time T_2 that satisfies the relationship:
The injection method for the fuel-injected internal combustion engine described in .