JPH0230920A - Fuel supply device for multiple valve engine - Google Patents

Abstract

PURPOSE:To unify the fuel intake quantity of respective intake ports by making the valve opening timing of respective intake valves for opening and closing both outside intake ports earlier than the valve opening timing of an intake valve for opening and closing a central intake port in three intake ports provided at a combustion chamber. CONSTITUTION:A multiple valve engine has three intake ports a-c provided for a single combustion chamber and also respective intake valves A-C provided at respective intake ports a-c and a single fuel injection valve I provided at the collecting portions of the respective intake ports a-c. In this case, in the respective intake ports a-c, the valve opening timing of the respective intake valve A, C for respectively opening and closing the respective intake ports 1, c of both the outsides is made earlier than the valve opening timing of the intake valve for opening and closing the central intake port b. Fuel is sufficiently taken into from both the outside intake ports a, c from which fuel is hard to be taken in by using inertia of intake flows. Accordingly, fuel distribution in the combustion chamber is unified.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a fuel supply system for a multi-valve engine equipped with three intake valves.

(Prior art) Providing multiple intake valves and multiple exhaust valves in a 4-stroke engine can improve intake and exhaust efficiency, reduce the weight of each valve, and improve followability and allowable maximum during high-speed operation. The rotation speed can be increased. Therefore, as disclosed in Japanese Utility Model Application Publication No. 61-186726, a five-valve engine has been proposed in which one combustion chamber is provided with three intake valves and two exhaust valves.

In such a five-valve engine, as shown in Fig. 4, three intake ports a, b, and c are provided for one combustion chamber, and each intake port a, b, and c has an intake valve A, In addition to arranging BSC respectively, intake ports a % b %
A fuel injection valve (■) is provided at the collecting part of C. The three intake valves A, B, and C are opened and closed at the same timing by three cams having the same profile.

However, when the three intake valves A, B, and C are opened and closed at the same timing, the center intake port b is located on the spray angle center line of the fuel injection valve ■, so there is no fuel in the center intake port b. Although it is easy to be inhaled, the inner and outer intake ports a,
Since c is away from the center of the fuel spray, it is the intake port a on both valve sides.

Since it becomes difficult for fuel to be sucked into C, the intake bow) a
There is a problem in that there is a difference in the amount of fuel inhaled between the combustion chambers -c, which makes the fuel distribution within the combustion chamber uneven and deteriorates the combustibility. In particular, when a narrow injection angle is used for the fuel injector I installed at the gathering part of intake ports a to C, this tendency is remarkable, and the adhesion of the air-fuel mixture to the wall at the port branch increases, resulting in deterioration of output and fuel efficiency. This was leading to a worsening of the situation.

(Objective of the Invention) Therefore, an object of the present invention is to provide a fuel supply device for a multi-valve engine that improves fuel efficiency and output by uniformizing the amount of fuel taken into each intake port.

(Structure of the Invention) As shown in FIG. 1, the present invention has three intake ports,
The opening timing of intake valves A and C, which open and close intake bows a and c on both valve sides of b and c, respectively, is earlier than the opening timing of intake valve B, which opens and closes central intake port b. It is characterized by

(Effects of the Invention) According to the present invention, by opening the intake valves A and C of the intake ports a and c on both valve sides where fuel is difficult to be sucked at an early stage, the inertia of the intake flow allows intake air to be drawn on both valve sides. Since sufficient fuel can be sucked in from ports a and c, the fuel distribution within the combustion chamber becomes uniform, and fuel adhesion to the walls is reduced.
It is possible to improve output and fuel efficiency.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 2 is a longitudinal sectional view of a DOHC type five-valve engine to which the present invention is applied, and FIG. 3 is a plan view showing the intake port portion thereof. Note that FIG. 2 is a sectional view taken along the line ■■ in FIG. 3.

In Fig. 2 and Part 3, 1 is a cylinder block;
2 is a cylinder head attached to the upper part. A combustion chamber 4 is formed in the cylinder head 2 at a portion corresponding to the cylinder 3 of the cylinder block 1, and an opening 6 is provided in the center of the combustion chamber 4 through which the tip of the spark plug 5 is exposed. In the combustion chamber 4, three intake bows 7a, 7b, and 7C are arranged in an arc shape and open on the left half of the opening 6, and each intake bow is open. a, 7b.

7c is provided with intake valves 8A, 8B, and 8C for opening and closing these, respectively. In addition, on the right half of the combustion chamber,
Two exhaust ports 9a and 9b are open, and the exhaust valve 1 is opened there.
0A and IOB are arranged respectively.

At the top of the cylinder head 2, a camshaft 11 has three cams arranged in parallel to drive the intake valves 8A to 8C, and a camshaft 12 has two cams arranged in parallel to drive the exhaust valves 10A and IOB. It is pivoted.

On the other hand, the three intake bows) 7a to 7C branched by the partition walls 13 and 14 are gathered together and communicated with the intake passage 15, and a wide-angle fuel injection valve 16 disposed in the gathering portion Fuel enters the combustion chamber 4 via the intake ports 7a to 7C.
It is designed to be injected inside. Fuel is supplied to the fuel injection valve 16 from a fuel distribution pipe 17.

In this embodiment, the valve opening timing is set so that the intake valves 8A and 8C disposed at the intake bows 7a and 7C on both valve sides open earlier than the intake valve 8B disposed at the central intake port 7b. This increases the flow velocity of the air-fuel mixture passing through the intake ports 7a, 7c on both valve sides, equalizes the fuel distribution within the combustion chamber 4, and improves the output. Also,
By increasing the flow rate of the mixture, the port bulkhead 13.1
Since it is possible to reduce fuel adhesion to the engine 4, it is also possible to improve fuel efficiency.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing the basic configuration of the present invention and its valve opening timing, and FIG. 2 is an explanatory diagram showing the basic configuration of the present invention and its valve opening timing, and FIG.
FIG. 3 is a longitudinal sectional view taken along line n, FIG. 3 is a plan view showing an intake port portion, and FIG. 4 is an explanatory diagram showing the valve opening timing of a conventional engine. 1...-Cylinder block 2...-Cylinder head 4...-Combustion chamber? a, 7 b, 7 C-intake port 8A, 8B,
8C--Intake valve a, 9b--Exhaust port OASl 0 B-Exhaust valve 1.12-Camshaft 3.14--Port bulkhead 5-Intake passage 16--Fuel injection valve

Claims (1)

[Scope of Claims] A multi-valve engine in which three intake ports are provided for one combustion chamber, each intake port is provided with an intake valve, and a fuel injection valve is provided at a gathering portion of the three intake ports. , A multi-valve engine characterized in that, among the three intake ports, the opening timing of the intake valves that open and close both outer intake ports, respectively, is earlier than the opening timing of the intake valve that opens and closes the central intake port. fuel supply system.