JPS6315546Y2 - - Google Patents

Description

[Detailed description of the invention] This invention is a multi-cylinder internal combustion engine with a fuel cut mechanism that divides multiple cylinders into two groups of cylinders, cuts fuel to one cylinder group, and enables operation using only the other cylinder group. It is about institutions.

Conventionally, in a multi-cylinder internal combustion engine, a plurality of cylinders are divided into two cylinder groups, and fuel is supplied to each cylinder group by a fuel injection pump having two independent fuel gears. By providing a fuel cut-off valve such as a solenoid valve at the entrance to one of the fuel gears of the fuel supply pipe that introduces the fuel sucked from the fuel tank by the fuel feed pump into the two fuel gears, and shutting off the solenoid valve. A multi-cylinder internal combustion engine with a fuel cut mechanism is used in which fuel is cut off to one of the fuel gears and fuel is supplied only to the other cylinder group for operation.

Such an internal combustion engine with a fuel cut mechanism can use one cylinder group from which fuel is cut off as a compressor, and by operating only the other cylinder group, it is possible to reduce the generation of white-blue smoke when the engine is operating at low temperatures. This is effective in preventing this, and is also effective in improving fuel consumption by using this fuel cut mechanism during low load operation of the engine.

However, even if the fuel supply to one fuel gear is cut off using a fuel cutoff valve such as a solenoid valve, fuel remains in the fuel gear, so there will be no fuel for a while after fuel cut is started. In particular, if one cylinder group from which fuel was cut is used as an air compressor, exhaust smoke will be supplied together with the compressed air, which is undesirable. There was a problem in that the effects of preventing blue smoke generation and improving fuel consumption at low loads were also halved.

Therefore, the present invention was devised to solve the above-mentioned problems in the conventional multi-cylinder internal combustion engine with a fuel cut mechanism. The purpose of this is to quickly drain the fuel at the same time as it is shut off.

The configuration of the present invention to achieve the above object is to divide a plurality of cylinders into two groups of cylinders, provide a fuel injection pump having two independent fuel gears for supplying fuel to each cylinder, and provide a fuel feed pump. In a multi-cylinder internal combustion engine with a fuel cut mechanism, in which a fuel cutoff valve is provided in each of the fuel supply pipe from one fuel gear to the fuel return pipe from the fuel gear, the fuel overflow from the fuel filter or fuel injection pump is removed. An ejector for generating negative pressure is disposed in the fuel return pipe that returns to the fuel tank, and a switching valve is provided between the fuel cutoff valve of the fuel supply pipe and one of the fuel gear entrances, and A switching valve is provided between the fuel cutoff valve of the fuel return pipe of the fuel gear and the outlet of the fuel gear, and either the inlet or the outlet of the fuel gear is connected to the suction part of the ejector, and the other is connected to the suction part of the ejector. The switching valves are characterized in that they are communicated via the switching valves so as to be openable to the outside.

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

First, in the multi-cylinder internal combustion engine with a fuel cut mechanism according to the embodiment of the present invention shown in the drawings, the eight cylinders numbered 1 to 8 are divided into a left bank cylinder group numbered 1, 3, 5, and 7, and a left bank cylinder group numbered 1, 3, 5, and 7; The fuel injection pump 11a supplies fuel to the left bank cylinder groups 1, 3, 5, and 7, which are divided into two cylinder groups of the right bank cylinder group indicated by 4, 6, and 8, and the right bank cylinder group 2, 4. , 6 and 8 are provided with independent fuel gears 12a and 12b, respectively.

Next, fuel is sucked from the fuel tank 13 by the fuel feed pump 14, and the fuel is supplied to each fuel gear 12 by the fuel supply pipe 15 having the fuel filter 20.
A, 12b is supplied with fuel, but on the downstream side of the fuel filter 20, a fuel supply line 15 is connected to two fuel gears 12a, 12b.
branched into two fuel supply pipes 15a and 15b,
Cylinder groups 1, 3, 5 on the left bank that cut fuel
Fuel supply pipe 15 to fuel gear gallery 12a for 7
A three-way solenoid valve 16 is provided as a fuel cutoff valve, and this fuel supply pipe 15 is connected via the three-way solenoid valve 16.
The inlet side of the fuel gear gallery 12a of a is the fuel tank 1.
It can communicate with a fuel return conduit 17 that communicates with the third side.

Further, the respective fuel return pipes 18a and 18b from the fuel gears 12a and 12b are also collected into one fuel return pipe 18 via an overflow valve 23 on the way, and the fuel tank 13
A three-way solenoid valve 19 is also provided as a fuel cutoff valve in the fuel return pipe 18a from the fuel gear gallery 12a for the left bank cylinder groups 1, 3, 5, and 7, which cuts off the fuel. has been established.

Further, fuel that overflows from the fuel filter 20 via an overflow valve 21 is returned to the fuel tank 13 via a fuel return pipe 22.

As described above, the three-way solenoid valves 16 and 19 are operated by the switch S, and the connections are made between the fuel supply pipe 15 and 15a, which is closed in relation to the control rack position, and between the fuel return pipes 18a and 18, respectively. By shutting off the left bank cylinder group 1,
A fuel cut mechanism is configured to cut off the fuel supply to the 3rd, 5th, and 7th sides.On the other hand, if the above-mentioned cut-off states are released, all the cylinders 1, 2, 3, 4, 5,
6, 7, and 8 are supplied with fuel, so that normal operating conditions can be obtained.

The three-way solenoid valves 16 and 19 are operated by a switch S and a power source B.

Therefore, in the fuel cut mechanism of the present invention, a fuel return pipe 22 from the fuel filter 20 and a fuel return pipe 18 from the fuel gears 12a, 12b are provided.
An ejector 25 for generating negative pressure is disposed in the fuel return pipe 24 where the two merge, and an ejector 25 for generating negative pressure is installed in the fuel return pipe 24 connected to the three-way solenoid valve 16 provided in the fuel supply pipe 15a to the fuel gear gallery 12a for the left bank. The end of the conduit 17 is opened to the suction section of the ejector 25.

Furthermore, a check valve 26 is interposed at one port of the three-way solenoid valve 19 provided in the fuel return pipe 18a from the fuel gear gallery 12a for the left bank, so that it can be opened to the atmosphere, and the operation of the three-way solenoid valve 19 This allows the fuel gear gallery 12a side of the three-way solenoid valve 19 of the fuel return pipe 18a to communicate with the atmosphere. That is, these three-way solenoid valves 16 and 19 are also used as switching valves.

In this case, there is no particular problem even if the check valve 26 is not provided.

Therefore, when operating the fuel cut mechanism of the present invention, by turning on the switches S of the three-way solenoid valves 16 and 19, fuel is supplied to the fuel supply pipe 1.
5 to 15a, the fuel in the cut bank fuel gear gallery 12a is sucked from the fuel supply pipe 15a via the three-way solenoid valve 16 and the pipe 17 by the ejector 25, and returns to the fuel tank 13. On the other hand, the fuel gear gallery 12 of the fuel return pipe 18a
Since the a side is opened to the atmosphere via the three-way solenoid valve 19 and the check valve 26, the fuel in the fuel gear gallery 12a can be quickly discharged.

In this case, the fuel discharge time conventionally required more than 10 minutes, but by applying the present invention, it can be shortened to less than 1 minute.

Here, the switch S may be provided with a delay relay, and after a certain period of time, for example, one minute, the cylinders 1, 3, 5, and 7 in the left bank on the fuel cut side may be operated as air compressors.

In the above embodiment, an example is shown in which the fuel injection pumps 11a and 11b are in line for a multi-cylinder internal combustion engine, but the fuel gear can also be divided into two parts for a series fuel injection pump. It can also be applied to either a V-type or an in-line multi-cylinder internal combustion engine.

Furthermore, in this embodiment, three-way solenoid valves 16 and 19 are provided in the fuel supply line 15a and the fuel return line 18a of the left bank fuel gear gallery 12a that cuts fuel, respectively, to function as a fuel cutoff valve and a switching valve. However, it is of course possible to provide the same functions by providing separate fuel cutoff valves, switching valves, etc., respectively.

Moreover, in this embodiment, the fuel gear 12
The inlet side of gear 12a is connected to the ejector 25 via the switching valve, and the outlet side of the gear rally 12a is opened to the outside air via the switching valve, but conversely, the inlet side is opened to the outside air and the outlet side is connected to the ejector 25. It may also be possible to communicate with. The point is that the structure should be such that the fuel on the side of the fuel gear that cuts the fuel can be sucked in by the action of the ejector and quickly discharged.

Therefore, in a multi-cylinder internal combustion engine to which the fuel cut mechanism of the present invention is applied, after fuel is cut from one bank of cylinders, the fuel in the fuel gear on the cut side immediately passes through the fuel return pipe. Since the fuel is discharged to the fuel tank side, when the cylinder group with fuel cut is used as an air compressor, the mixture of exhaust smoke in the compressed air is immediately prevented, and it can be used as a complete air compressor. This has the advantage of further improving the effects of preventing white smoke and improving fuel consumption at low loads.

In particular, in the multi-cylinder internal combustion engine with a fuel cut mechanism of the present invention, an ejector for generating negative pressure is provided in the fuel return line, and the negative pressure is used to actively suck residual fuel from the fuel gear. Therefore, the fuel discharge time is fast, and since internal combustion engines with such an ejector installed in the fuel return line are already in use, in that case, the ejector can be easily applied for the purpose of the present invention. There is an advantage that the cost for applying the present invention is low.

[Brief explanation of the drawing]

The drawing is a system diagram of a multi-cylinder internal combustion engine with a fuel cut mechanism according to the present invention. 1, 2, 3, 4, 5, 6, 7, 8... cylinder, 1
1a, 11b...Fuel injection pump, 12a, 12
b...Fuel gear gallery, 13...Fuel tank, 14
...Fuel feed pump, 15, 15a, 15b
... Fuel supply pipe, 16, 19 ... Three-way solenoid valve,
17... Pipe line, 18, 18a, 18b... Fuel return pipe line, 20... Fuel filter, 22, 24...
Fuel return pipe, 25... ejector, 26... check valve.

Claims (1)

[Scope of utility model registration request] A plurality of cylinders are divided into two groups of cylinders, and a fuel injection pump having two independent fuel gears for supplying fuel to each cylinder is provided, and a fuel supply pipe line from the fuel feed pump to one of the fuel gears is provided. For generating negative pressure in the fuel return line that returns overflowing fuel from the fuel filter or fuel injection pump to the fuel tank in a multi-cylinder internal combustion engine with a fuel cut mechanism in which each fuel return line from the fuel gear gallery is provided with a fuel cutoff valve. A switching valve is provided between the fuel cutoff valve of the fuel supply pipe and one of the fuel gear inlets, and a switching valve is provided between the fuel cutoff valve of the fuel supply pipe and the fuel return pipe of the fuel gearary. A switching valve is disposed between the fuel gear and the outlet of the fuel gear, and either the inlet or the outlet of the fuel gear is connected to the suction part of the ejector, and the other is communicated via the switching valve so that the other can be opened to the outside. A multi-cylinder internal combustion engine with a fuel cut mechanism.