JPH0658103B2 - Air intake system for fuel injection engine - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intake system for a fuel injection engine having two intake passages for each cylinder and a fuel injection valve for each passage. .

(Prior Art) In the conventional intake system for such a fuel injection engine, as shown in Japanese Utility Model Laid-Open No. 167254/1982, one surge tank is provided in the middle of the intake passage, and each surge tank is connected to each cylinder. On the other hand, by arranging two systems of intake passages, each consisting of an intake passage for low speed and an intake passage for high speed which is opened at high speed, the intake flow rate is increased and passage resistance is reduced in any operating condition. Then, the fuel and air are mixed well to increase the combustion speed to improve the fuel consumption, and the intake charging efficiency is improved to improve the output.

However, the conventional one as described above is provided in each intake system by the detection signal of the total intake amount from one intake air measuring means (air flow meter) provided in the common intake passage upstream of the surge tank. Since the fuel injection amount of the fuel injection valve is controlled, the air-fuel ratio (A / F) of each system becomes improper, and there is a problem that the variation is large especially when switching from low speed to high speed.

(Object of the Invention) The present invention has been made in view of the above circumstances, and by providing independent intake air metering means in each of the two intake passages, it is possible to ensure that fuel corresponding to the amount of air is supplied from each intake passage. It is an object of the present invention to provide an intake system for a fuel injection engine that can supply the fuel to the engine and prevent the air-fuel ratio of the air-fuel mixture supplied from each system from becoming uneven.

(Structure of the Invention) The present invention provides, for each cylinder of the engine, a first intake passage that constantly supplies intake air, and a second intake passage that is closed by the opening / closing means at low speed and supplies intake air only at high speed. 2
In an intake device of a fuel injection type engine, which constitutes an intake passage of a system and in which each of the intake passages is provided with a fuel injection valve,
The intake passages of each system are collected for each system, and intake air measuring means is provided upstream of each collecting portion for each system, and the fuel injection valve corresponding to each system is based on the detection signal from these intake air measuring means. And a fuel injection control means for controlling each of the above.

With this configuration, each intake system can be measured without being affected by each other's intake systems in any operating state, and fuel injection proportional to the intake air amount of each intake system can be performed.

Embodiment An embodiment of the present invention will be described below with reference to the drawings. FIGS. 1 and 2 show the construction of a four-cylinder engine as an embodiment of the engine intake system of the present invention, where 1, 2, 3, and 4 are the first, second, third, and third engine E, respectively. 4 cylinders,
1P, 2P, 3P, and 4P are low-speed intake ports for the first to fourth cylinders, and 1S, 2S, 3S, and 4S are high-speed intake ports for the first to fourth cylinders, respectively. It has an intake valve. 11P, 12P, 13P, 14P
Are low-speed branch intake passages (first intake passages) each having a downstream end connected to each cylinder, 11S, 12S, 13S,
14S is a similarly provided high-speed branch intake passage (second
Intake passages), 5P, 5S are provided at the upstream ends of the above-described low-speed and high-speed branch intake passages of two systems, and surge tanks (collecting parts) 6P, 6S are collected for each system, and the surge tanks 5P , 5S are located on the upstream side of high-speed and low-speed intake passages, and 7P and 7S are intake air measuring means (hereinafter referred to as air flow meters) provided in the intake passages 6P and 6S, respectively. The attached air flow meter is shown. 8P and 8S are the surge tanks 5P and 5S and the air flow meter 7P, respectively.
A throttle valve provided in the intake passages 6P, 6S between 7S and operating in conjunction with each other, and 9 is an air cleaner 10P, 10 to which the upstream ends of the intake passages 6P, 6S are assembled and connected.
S is a fuel injection nozzle provided in each branch intake passage of each system, and SV is an opening / closing means which is provided in the high-speed branch intake passage and is a shutter valve that opens during high-speed operation of the engine.

Reference numerals 20P and 20S denote fuel injection control means, respectively, which control means detect signals from the air flow meters 7P and 7S, an engine speed signal 21 and an engine load signal 2.
2, the fuel injection valves 10P, 10S and the on-off valve SV
It outputs a signal to the actuator 23 that drives the.

The operation of the above configuration will be described. When the engine speed is a low speed up to the set speed N1, the fuel injection control means 20P, 20
Due to S, the on-off valve SV is closed and the high-speed branch passage is closed, and the low-speed branch intake passage 11P, which is connected to this via the intake passage 6P and the surge tank 5P,
Air is taken into each cylinder 1, 2, 3, 4 from 12P, 13P, 14P. At this time, the fuel injection valve 10P is driven with a pulse width corresponding to the intake air amount detected by the air flow meter 7P, so that the air-fuel mixture having an appropriate air-fuel ratio is supplied to each cylinder. When the rotation speed of the engine reaches the set speed N1, the opening / closing valve SV starts to open via the actuator 23, and when it reaches the set opening θ, the fuel injection valve 10S starts the fuel injection with the set minimum pulse width. To do. That is, since the detection error of the air flow meter is large during the period of the small opening up to the set opening θ, the fuel is not injected from the fuel injection valve 10S, but is injected by the fuel injection valve 10P until then. After the set opening θ is reached, each fuel injection valve 10P, 10S is driven with a pulse width corresponding to the amount of air detected by each air flow meter 7P, 7S to inject fuel. Therefore, fuel is injected with the same air-fuel ratio on both the low speed side and the high speed side.

The air flow meters 7P and 7S are not limited to the ones in the above-described embodiment, but those that detect the negative pressure of the intake system or those that use the correction value of the opening of the throttle valve are used to detect the air amount equivalent. It may be configured to.

Further, although the embodiment with four cylinders has been described above, the present invention is not limited to this, and the present invention can be similarly applied to engines with six cylinders, eight cylinders, and the like.

Further, the intake port in each cylinder is
Although the intake 2-valve system has been described, the intake 1-valve system in which the intake branch passages merge near the intake port can also be implemented in the same manner.

(Effects of the Invention) As is apparent from the above description, according to the present invention, the first intake passage for constantly supplying intake air and the second intake passage for supplying intake air only at high speed are provided for each cylinder of the engine. Two intake air passages are provided, fuel injection valves are provided in these intake air passages, and intake air metering means are independently provided for each system. Based on detection signals from the intake air metering means, By configuring each fuel injection valve to be controlled, it is possible to measure the air without being affected by the intake air amount in the other intake systems. Therefore, from low speed to high speed, the fuel proportional to the air amount can be accurately measured in each system. Can be injected, and a uniform air-fuel mixture can be obtained.

[Brief description of drawings]

FIG. 1 is a plan view of an intake system for a fuel injection engine according to an embodiment of the present invention, and FIG. 2 is a schematic side view of the same. 1, 2, 3, 4 ... Cylinder, 11P, 12P, 13P, 1
4P ... Branch intake passage for low speed, 11S, 12S, 13
S, 14S ... Branch intake passage for high speed, 5P, 5S ...
Surge tank, 6P ... intake passage for high speed, 6S ... intake passage for low speed, 7P, 7S ... intake air measuring means, 1
0P, 10S ... Fuel injection valve, 20P, 20S ... Fuel injection control means, SV ... Open / close valve.

Continuation of the front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location F02M 69/00 360 C 7825-3G

Claims (1)

[Claims] 1. A first intake passage for always supplying intake air and a second intake passage for closing intake air at a low speed by the opening / closing means and supplying intake air only at a high speed, for each cylinder of the engine.
In an intake device for a fuel injection engine in which two systems of intake passages are provided, and each of the intake passages is provided with a fuel injection valve, the intake passages of each system are collected for each system, and each collecting unit is for each system. A fuel injection engine characterized in that intake air measuring means is provided upstream and fuel injection control means is provided for controlling the fuel injection valves corresponding to each system based on detection signals from these intake air measuring means. Intake device.