JPH0437274B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a fuel injection device for an engine, particularly an engine fuel injection device in which a plurality of intake passages are opened in one combustion chamber and a fuel injection valve is provided in each intake passage. This relates to a type of fuel injection device.

(Prior art) Multiple intake passages are opened in one combustion chamber,
Engine intake systems in which each intake passage is provided with a combustion injection valve are known. For example, Tokushoko 53−
Publication No. 43616 discloses that a side housing and an intermediate housing of a rotary piston engine are provided with primary and secondary intake passages that open into the same working chamber, and that the primary and secondary injection valves of these intake passages are connected to each other. A fuel injector is disclosed. During low load operation when intake air is carried out only through the primary intake passage, fuel is injected only from the primary side injection valve, and during high load operation when intake air is carried out from both intake passages, fuel is injected from both injection valves. It is done. In addition, although the type does not have multiple intake passages, the engine is equipped with a main fuel injector that injects fuel throughout the engine's operating range, and an auxiliary fuel injector that injects fuel in the engine's high-load operating range. The fuel injection device is
This is disclosed in Japanese Patent Publication No. 54-53718, and this publication shows a fuel supply pipe that can also be used in the device described in Japanese Patent Publication No. 53-43616 mentioned above. However, in these known fuel injection devices, the injection valve that injects fuel during high load,
In other words, the secondary fuel injection valve of Japanese Patent Publication No. 53-43616 or the auxiliary fuel injection valve of Japanese Patent Publication No. 54-53718 is
Since fuel is not injected when the engine is running at low load, fuel accumulates in the fuel pipe near the fuel injection valve and is warmed by the engine heat, causing bubbles, a so-called percolation phenomenon. There is a risk of causing Therefore, when the next high-load operation is started, a problem arises in that a predetermined amount of fuel is not injected from the high-load fuel injection valve.

(Object of the Invention) As described above, the present invention provides a fuel injection system for an engine that is equipped with a fuel injection valve that injects fuel in a high-load operating range as well as a fuel injector that injects fuel in all engine operating ranges. The objective is to suppress the occurrence of percolation in a device and enable stable fuel supply.

(Structure of the Invention) In order to achieve the above-mentioned object, the present invention has the following structure. That is, the fuel injection device for an engine according to the present invention includes first and second fuel injection valves provided in an intake passage, and a fuel pipe that supplies fuel pumped from a fuel pump to the first and second fuel injection valves. and a control device that controls injecting fuel from the first fuel injector in all engine operating ranges and injecting fuel from the second fuel injector in high-load operating ranges, the features of which are as follows: This is because the second fuel injection valve is connected to the fuel pipe upstream of the first fuel injection valve.

The present invention has a type in which the first and second fuel injection valves are provided in one intake passage, and a plurality of intake passages opening into one combustion chamber, and the first and second fuel injection valves are provided in different intake passages. It can be applied to any type provided in the intake passage.

(Effects of the Invention) In the present invention, since the second fuel injection valve is connected to the fuel pipe on the upstream side of the first fuel injection valve, the second fuel injection valve Fuel does not accumulate in the vicinity of the fuel injection valve, so the occurrence of percolation due to the accumulated fuel is suppressed, and stable fuel supply from the second fuel injection valve becomes possible.

(Description of an Embodiment) The figure shows an example in which the present invention is applied to a four-cylinder engine, in which each combustion chamber 2 formed in a cylinder block 1 has two exhaust ports 3 and a primary intake port 4. and the secondary intake port 5 is open. The primary intake ports 4 are each connected to a primary branch intake passage 7 that branches from a collecting pipe 6 forming a primary surge tank, and the secondary intake ports 5 are connected to a secondary branch intake passage 7 that branches from a collecting pipe 8 forming a secondary surge tank. It is connected to the branch intake passage 9. The primary branch intake passage 7 is connected to a primary intake passage 11 having a primary throttle valve 10 via a collecting pipe 6, and the secondary branch intake passage 9 is connected to a secondary intake passage having a secondary throttle valve 12 via a collecting pipe 8. 13. Furthermore, the intake passage 11,
13 is connected to a main intake passage 20 having an air cleaner 14 and an intake flow meter 15. The secondary throttle valve 12 begins to open when the primary throttle valve 10 is almost fully opened, and allows high-load intake air to flow through the secondary intake passage 13.

A primary fuel injection valve 16 is provided in each of the primary branch intake passages 7 in close proximity to the combustion chamber 2, and a secondary fuel injection valve 17 is provided in each of the secondary branch intake passages 9.
is located further away from the combustion chamber 2 than the primary fuel injection valve 16 . As a fuel supply device for supplying fuel to the fuel injection valves 16 and 17, a fuel pump 19 is provided which pumps fuel from a fuel tank 18, and a discharge port of this fuel pump 19 is connected to a fuel pipe 22 having a filter 21. It is connected. The fuel pipe 22 is sequentially connected to the second fuel injection valve 17 on the upstream side and to the first fuel injection valve 16 on the downstream side. Further, the downstream end of the fuel pipe 22 is connected to the fuel tank 1 via a pressure regulator 23.
8 is connected.

The pressure regulator 23 has a diaphragm 23d that divides the inside of the case 23a into a fuel chamber 22b and a negative pressure chamber 23c, and the fuel chamber 23b is connected to the fuel tank 1.
It is open to 8. The end of the fuel pipe 22 opens in the fuel chamber 23b facing the diaphragm 23d, and the gap between the end of the fuel pipe 22 and the diaphragm 23d is controlled by the pressure in the negative pressure chamber 23c. . A spring 23e that pushes the diaphragm 23d toward the end of the fuel pipe 22 is disposed inside the negative pressure chamber 23c.
c is connected to the primary intake passage 7 by a negative pressure line 24. Furthermore, a branch line 25 is provided in the negative pressure line 24 , and this branch line 25 is connected to the secondary intake passage 9 . A solenoid valve 26 is arranged in the branch line 25, and when the solenoid valve 26 is closed, the intake negative pressure of the primary intake passage 7 is introduced into the negative pressure chamber 23c, and the solenoid valve 26
When the intake passages 7 and 9 open, the average of the intake negative pressures of both the intake passages 7 and 9 is introduced into the negative pressure chamber 23c.

The engine is further provided with a speedometer 27 for detecting its rotational speed, and the flow rate signal from the intake flowmeter 15 and the speed signal from the speedometer 27 are input to a control circuit 28 consisting of a microcomputer. The control circuit 28 calculates the fuel supply amount according to the engine operating state based on the input signal, and controls the first and second fuel injection valves 16, 16,
17 is activated. Further, the output of the control circuit 28 is also given to the solenoid valve 26, and the solenoid valve 26 is opened in an operating range where fuel injection is performed from the second fuel injection valve 17.

In the above configuration, in an operating region where fuel is not injected from the second fuel injection valve 17, fuel is sent through the fuel pipe 22, and is injected from the first fuel injection valve 16 connected downstream thereof. Ru. Therefore, in the upstream portion to which the second fuel injection valve 17 is connected, the amount injected from the first fuel injection valve 16 and the amount injected from the pressure regulator 23 to the fuel tank 18
In other words, the entire discharge amount of the fuel pump 19 flows through the fuel pipe 22, and fuel does not accumulate near the second fuel injection valve 17. . Further, when the engine load increases to a high load region, fuel is injected from the second fuel injection valve 17 as well, but at this time, the negative pressure chamber 23c of the pressure regulator 23 is filled with the intake negative pressure in the primary intake passage 7. Since the average value of the intake pressure and the intake negative pressure in the secondary intake passage 9 is given, more accurate control is possible than when only the intake negative pressure in the primary intake passage 7 is given.

[Brief explanation of drawings]

The drawing is a schematic diagram of an engine showing an embodiment of the present invention. 2...Combustion chamber, 4...Primary intake port, 5...Secondary intake port, 7...Primary branch intake passage, 9...Secondary branch intake passage, 10...Primary throttle valve, 12...Secondary Throttle valve, 15... Intake flow meter, 16... First fuel injection valve, 17... Second fuel injection valve, 19... Fuel pump, 22... Fuel pipe, 28... Control circuit.

Claims (1)

[Claims] 1 first and second fuel injection valves provided in the intake passage, a fuel pipe that supplies fuel pressure-fed from a fuel pump to the first and second fuel injection valves, and a first and second fuel injection valve provided in the intake passage; In the fuel injection device for an engine, the second fuel injection valve is configured to inject fuel from the first fuel injection valve and a control device for controlling the second fuel injection valve to inject the fuel in a high-load operation region. A fuel injection device for an engine, characterized in that the fuel injection device is connected to the fuel pipe on an upstream side of an injection valve.