JPH0235151B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a single-point fuel control device for supplying an air-fuel mixture for an internal combustion engine.

[Conventional technology]

In a single-point fuel control system where a fuel injection valve is installed upstream of the throttle valve and supplies air-fuel mixture to the engine, air control is installed in a passage that bypasses the throttle valve to control idle rotation when the cooler is loaded or when starting and warming up. A fuel control system is provided that includes a valve to control the idle air flow path. However, in a fuel control device with such a structure, when the air control valve is closed, fuel accumulates in the bypass passage near the valve upstream of the air control valve.
This fuel flows out when the valve is operated, which has the disadvantage of making the mixture too rich.

FIG. 1 is an example of a conventional single-point fuel control system. Fuel is supplied to the engine by a fuel injection valve 2 installed in the intake cylinder 3 upstream of a throttle valve 5 that is located in the intake cylinder 8 that supplies air to the engine and controls the air flow rate.
The main body 1 is provided with an air passage 6 that bypasses the throttle valve 5, and an air control ON-OFF valve 4 is disposed within this bypass air passage 6.
By opening the ON/OFF valve 4, the idle air flow rate is increased when the cooler is loaded, when starting and warming up, etc., and the idle speed is controlled to an appropriate value. In the single-point fuel control device that operates in this manner, as described above, the fuel injected from the fuel injection valve 2 is transferred to the bypass passage inlet 6.
Fuel enters from point a, and when the ON/OFF valve 4 is not operating, fuel accumulates in the upstream passage 7 near the valve. Therefore, when the ON/OFF valve is operated, this accumulated fuel instantly enters the engine through the bypass passage 6, producing harmful components such as CO and HC in the exhaust gas, which not only impairs fuel economy but also causes severe damage. In some cases, there were problems such as the engine stopping.

[Purpose of the invention]

The present invention has been proposed in order to solve these shortcomings, and it is an object of the present invention to provide a single-point fuel control device in which fuel does not accumulate near the valve upstream of the air control valve.

[Summary of the invention]

According to the present invention, in order to achieve the above object, there is provided an intake passage for supplying air to the engine, a throttle valve provided in the intake passage, and a fuel injection hole located upstream of the throttle valve and opened in the intake passage. a fuel injection valve that connects the upstream and downstream of the throttle valve, a bypass passage provided in the bypass passage, and an amount of bypass air that is supplied by bypassing the throttle valve when the engine load fluctuates or when the engine is warmed up. In a fuel control device comprising a bypass air control valve that adjusts the air flow rate by opening and closing the throttle valve, the entrance of the air passage that bypasses the throttle valve is provided above the cone of fuel injected from the fuel injection valve. and the air metering portion of the air control valve is disposed above the air passage inlet.

[Embodiments of the invention]

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

In FIGS. 2a and 2b, the air passages that bypass the throttle valve are the upstream passage 6b of the ON/OFF valve 4,
6c, 6d and a downstream passage 6e. The entrance 6a of this bypass passage is connected to the fuel injection valve 2.
It is opened above the cone 15 of fuel injected from the cone 15, thereby preventing fuel from flowing into the bypass passage 6b. Furthermore, the upstream passages 6b, 6c, and 6d of the ON/OFF valve 4 are arranged such that the axial centers of the passages are located upward as they move from the upstream passage to the downstream passage, so that in the event that fuel flows into the passage 6a, it will also flow downstream. It has a structure that prevents it from flowing into the passage. The above structure not only prevents fuel from flowing into the bypass passage 6b, but also prevents fuel from flowing into the bypass passage 6b.
This prevents a problem in which the oil flows into the engine through the downstream passage 6e along with the operation of the engine.

FIG. 3 shows a second embodiment. As in the previous embodiment, the bypass air passage inlet 110a is disposed above the fuel cone 15 to prevent fuel from flowing into the bypass passage 110. Further, in this embodiment, a proportional control valve 120 having a measuring section 130 is installed vertically above the bypass passage 110b. With such a passage configuration, even if fuel flows into the passage 110b, it will not flow out to the downstream passage 110c through the air metering section 130, and as in the previous embodiment, the fuel will accumulate near the proportional control valve 4 and when the valve is operated. It is possible to prevent the problem of this fuel flowing out. Furthermore, even when the proportional control valve 4 is in operation, it is possible to prevent the metering accuracy of the valve from deteriorating due to the fuel passing through the metering section 130.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a conventional example, FIG. 2 is a sectional view of one embodiment of the present invention, and FIG. 3 is a sectional view of another embodiment. 4... Valve, 6a... Passage entrance, 6a-6d
...Upstream passage, 6e...Downstream passage, 100, 13
0...Air measuring section.

Claims (1)

[Scope of Claims] 1. An intake passage supplying air to the engine, a throttle valve provided in the intake passage, a fuel injection valve located upstream of the throttle valve and opening its fuel injection hole into the intake passage, and the throttle valve. A bypass passage connecting the upstream and downstream of the throttle valve is provided in the bypass passage, and the amount of bypass air supplied by bypassing the throttle valve is controlled by the opening and closing of the throttle valve, which is provided in the bypass passage and controls the amount of bypass air that is supplied by bypassing the throttle valve when the engine load fluctuates or when starting and warming up the engine. In a fuel control device comprising a bypass air control valve that is adjusted by operation, an inlet of the bypass passage on the upstream side of the throttle valve is provided above the fuel cone injected from the fuel injection valve, and the bypass air control valve A fuel control device characterized in that an air metering section is located above an upstream entrance of the bypass passage. 2. In claim 1, the bypass passage from the inlet of the bypass passage upstream of the throttle valve to the air metering section of the bypass air control valve,
A fuel control device characterized in that the axial center of the passage is located upward as it goes from the upstream passage to the downstream passage.