JP3322563B2 - Fuel / water injection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a fuel-water injection diesel engine to reduce the NO _x.

[0002]

2. Description of the Related Art First, a description will be given of a most common fuel / water injection device of a first conventional example. FIG. 5 shows a conventional water injection device,
FIG. 6 shows the characteristic diagram. Fuel from the high-pressure pump 10 passes through the high-pressure passage 12 through the discharge valve 14 and is injected from the injection nozzle 20 into the combustion chamber of the internal combustion engine and burns.

Here, the injection nozzle 20 is constituted by an automatic valve having a needle valve 21 whose valve opening pressure is set by a spring 22.
In order to suppress the generation of NO _x during combustion of the fuel, water 30 whose pressure has been increased to a pressure lower than the valve opening pressure of the injection nozzle 20 by a hydraulic pump (not shown) is supplied to the solenoid valve during a period in which the high pressure pump 10 is not operating. By opening the check valve 31, the check valve 3
2, the water is injected back into the high-pressure fuel passage 12 from the water injection point 40 of the high-pressure fuel passage 12.

At this time, the injection nozzle 20
Since the high-pressure fuel passage 41 on the side of the pump stops at the dead end, water flows in the direction of the high-pressure pump 10. The fuel displaced by this water inflow returns from the check valve 13 provided on the high-pressure pump 10 side of the high-pressure fuel passage 12 through the high-pressure pump 10 to the oil supply passage 11. The check valve 13 has a spring 15 and opens at a pressure lower than the valve opening pressure of the injection nozzle 20. When the required amount of water has flowed in, the solenoid valve 31 is closed and the flow of water is stopped.

In the next cycle, the high-pressure pump 10 operates,
When fuel is injected from the injection nozzle 20 through the discharge valve 14 and the high-pressure fuel passage 12, water is injected into the high-pressure fuel passage 12 so that the fuel is injected as shown in FIG. That is, first, the fuel in the high-pressure fuel passage 41 downstream from the water injection point 40 is injected as shown in FIG. 6A, and then the injected water is injected as shown in FIG. Fuel C in the passage 12 is injected. Since the results middle water injection into the combustion chamber is applied, the occurrence of the combustion temperature decreases NO _x is kept low.

[0006]

However, in the above-described conventional example, a period B of only water occurs during fuel injection.
If the injection amount of water is increased for the purpose of further reducing NO _x , the combustion in the combustion chamber temporarily stops, the combustion becomes unstable, and the rotation of the internal combustion engine itself becomes unstable. For this reason, the amount of water to be injected is limited, and NO _x cannot be reduced to a certain value or less.

Next, a second conventional example (Japanese Utility Model Laid-Open No. 5-1658)
Is a mixing means for mixing the emulsion fuel, a free piston part provided in the injection pipe of the injection pump and the injection nozzle and fitted with a free piston, and a check valve for the emulsion fuel sent from the mixing means to the free piston part. The present invention has an emulsion fuel supply means for supplying the fuel through the fuel tank, so that starting failure due to separation of the emulsion fuel is prevented, and deterioration of the durability of the injection system components is prevented.

Further, a third conventional example (Japanese Utility Model Laid-Open No. 5-1265)
9) The first fuel stored in the first fuel tank and the second fuel
Mixing means for mixing the second fuel stored in the fuel tank of the fuel and mixing the emulsion fuel, and a non-return valve for the injection pipe between the injection pump and the injection nozzle for the emulsion fuel sent from the mixing means. Since the fuel supply means is provided with the emulsion fuel supply means, the starting failure due to the separation of the emulsion fuel can be prevented, and the deterioration of the durability of the injection system components can be prevented.

An object of the present invention is to solve the above-mentioned problems of the conventional apparatus, to secure the minimum necessary fuel E for continuing combustion even during water injection, and to secure stable engine performance without interruption of combustion. It is to provide a fuel / water injection device.

[0010]

According to a first aspect of the present invention, there is provided a fuel / water injection apparatus comprising: a high-pressure pump for pumping fuel; and a discharge valve for passing only a flow from the high-pressure pump to an injection nozzle at an outlet of the high-pressure pump. 14 and a check valve 13 that passes only the flow from the injection nozzle to the high-pressure pump in parallel with the discharge valve, is provided , and merges downstream of the discharge valve 14 and the check valve 13 to the injection nozzle. concatenated with the high-pressure fuel passage 12, fuel, water injection system having a connection point 40 between the water supply pipe 30 for injecting water during the high-pressure fuel in the high pressure fuel passage is not <br/> act In the outlet of the high-pressure pump 10, a new high-pressure fuel passage 120 having a check valve 140 for preventing backflow of fuel is provided in parallel with the high-pressure fuel passage, and a junction of the new high-pressure fuel passage and the high-pressure fuel passage is provided. 400 Characterized in that provided downstream position of the connecting point comprising the high-pressure fuel passage and the connection point 40 between the water supply pipe.

A fuel / water injection valve according to a second aspect of the present invention includes a high-pressure pump 10 for pumping fuel, a discharge valve 14 for passing only the flow from the high-pressure pump to the injection nozzle 20 at the outlet of the high-pressure pump, and the discharge valve. A check valve 13 that passes only the flow from the injection nozzle to the high-pressure pump is provided in parallel, and is joined downstream of the discharge valve 14 and the check valve 13 to be connected to the injection nozzle. High pressure fuel passage 12,
In fuel and water injection device having a connection point 40 between the water supply pipe 30 for injecting water in the period in which the high-pressure fuel does not act on the high-pressure fuel passage, the high-pressure fuel passage to the outlet of the high pressure pump 10 Check valve 1 to prevent fuel backflow in parallel with
A new high-pressure fuel passage 120 having a midway 40 is provided, and a junction 410 between the new high-pressure fuel passage and the high-pressure fuel passage is provided upstream of a connection point 40 between the high-pressure fuel passage and the water supply pipe. Features.

[0012]

When the high-pressure pump is not operating, the solenoid valve is turned off.
When 1 is released, pressurized water always flows into the high-pressure injection pipe 12 from the injection point 40. Downstream of the injection point 40, there is an injection nozzle 20 having a valve opening pressure higher than the injection pressure, and the injection is stopped, so that injection does not flow in this direction. However, since the check valve 13 is provided at the end of the pipe 12 to the high-pressure pump 10 side, the pressurized water pushes open the check valve 13 that allows only the flow to the high-pressure pump, and the check valve 13 is provided. Water is injected only into line 12.

Next, when the high-pressure pump operates to discharge fuel, both discharge valves 14, 140 are pushed open. The injection nozzle first injects a portion 41 of the fuel only in the pipe 12 and then simultaneously injects water and fuel in the pipes 12 and 120. When the injection of the water portion is completed, only the fuel is injected into the combustion chamber. Is done. By shortening the period during which only water is injected as in the first invention or making it zero as in the second invention, water and fuel can be injected simultaneously, combustion is stabilized, and NO
The reduction of _x can be increased.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment and a second embodiment of the present invention will be described below with reference to FIGS. First,
A first embodiment will be described. FIG. 1 is an overall view of the first embodiment, and FIG. 2 is an injection characteristic diagram of the injection nozzle. 10
Is a high-pressure pump, and fuel is supplied to a fuel inlet 11 from a refueling pump (not shown). 14 is a discharge valve that allows only the flow from the high pressure pump to the injection nozzle, 13 is a check valve that allows the flow from the injection nozzle to the high pressure pump, and 15 is a valve opening pressure setting spring.

The oil passages from the check valve 13 and the discharge valve 14 join and are connected to the high-pressure fuel passage 12, and further from the high-pressure fuel passage 41 to the injection nozzle 20. 21 is an injection nozzle main body, and 22 is a valve opening pressure setting spring of the injection nozzle.

Reference numeral 30 denotes a water supply pipe pressurized by a pump (not shown) to a pressure lower than the valve opening pressure of the injection nozzle 20,
31 is a solenoid valve for controlling the supply water, 32 is a check valve provided on the water supply pipe 30 and allows only the flow toward the high-pressure fuel passage, and 40 is a check valve for the water supply pipe 30 and the high-pressure fuel oil passage 12. Is the point of water injection where they meet. Reference numeral 120 denotes a new high-pressure fuel passage, and 140 denotes a check which is located in the middle of the new high-pressure fuel passage 120 provided in parallel with the check valve 13 and the discharge valve 14 and allows a flow from the high-pressure pump 10 to the injection nozzle 20. It is a valve. Reference numeral 400 denotes a junction of the two high-pressure fuel passages, which includes the water injection point 40 in this figure and is located downstream thereof.

The operation of the first embodiment will be described. When water is injected from the water injection point 40 while the high-pressure pump 10 is not operating, the water is injected only into the high-pressure fuel oil passage 12. Next, when the high-pressure pump 10 operates during engine operation, FIG.
Fuel and water are injected as shown in FIG. That is, the fuel in the high-pressure fuel passage 41 is first injected as shown in FIG.

Next, the water in the high-pressure fuel passage 12 upstream of the water injection point 40 and the fuel in the new high-pressure fuel passage 120 are both injected as shown in FIGS. After the injection of the injected water is completed, only the fuel is injected as shown in FIG. Therefore, there is no longer a period in which only water is injected as in the conventional example, and a minimum amount of fuel E necessary for continuing combustion even during water injection is secured.
Stable operation of the engine can be ensured without interruption of combustion. The junction 400 of the high-pressure fuel passage may be at the same position as the water injection point 40.

Next, a second embodiment will be described. FIG.
Is an overall view of the second embodiment, and FIG. 4 is an injection characteristic diagram of the injection nozzle of the second embodiment. The constituent members are the same as in the first embodiment, and a description thereof will be omitted. However, the junction 410 between the high-pressure fuel passage 12 and the new high-pressure fuel passage 120 is the water injection point 4
It differs from the first embodiment in that it is located upstream of 0.

Next, the operation will be described. When water is injected from the water injection point 40 during a period when the high-pressure pump 10 is not operating, the water is injected from the water injection point 40 to the junction 4 of the high-pressure fuel passage.
Up to 10, only water is provided, and water is injected into the high-pressure fuel passage 12.

Next, when the high-pressure pump 10 operates, fuel and water are injected as shown in FIG. First, the high-pressure fuel passage 4
1 is injected, then only water B from the water injection point 40 to the high-pressure fuel passage junction 410 is injected, and then the water in the high-pressure fuel passage 12 and the fuel in the new high-pressure fuel passage 120 are D, E And finally fuel C is injected.
Here, only water is injected as B, but the amount is not so large, and is set to such an extent that the effect of reducing NOx can be obtained without interrupting combustion.

[0022]

According to the fuel / water injection device of the present invention, the minimum required fuel E for continuing the combustion even during the water injection can be secured, and the stable operation of the engine can be ensured without interruption of the combustion. Can be increased from the conventional limit value, and the emission amount of NOx can be reduced.

[Brief description of the drawings]

FIG. 1 is an overall view of a first embodiment of the present invention,

FIG. 2 is a characteristic diagram of the injection nozzle of FIG. 1;

FIG. 3 is an overall view of a second embodiment of the present invention,

FIG. 4 is a characteristic diagram of the injection nozzle of FIG. 3;

FIG. 5 is an overall view of a conventional technique,

FIG. 6 is a characteristic diagram of a conventional injection nozzle.

DESCRIPTION OF SYMBOLS 10 ... High pressure pump, 12 ... High pressure fuel passage, 13 ... Check valve, 14 ... Discharge valve, 140 ... Discharge valve, 120 ... New high pressure fuel passage, 15 ... Spring, 20 ... Injection nozzle, 21 ... Fuel nozzle body, 22: spring, 30: water supply pipe, 31: solenoid valve, 32: check valve, 40: water injection point, 400, 410 ...
High-pressure fuel passage junction, A, C, E: fuel, B, D: water.

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F02M 25/022 F02B 47/02 F02D 19/12 F02M 43/00

Claims (2)

(57) [Claims] 1. A high-pressure pump (10) for pumping fuel,
A discharge valve (14) that allows only the flow from the high-pressure pump to the injection nozzle (20) to pass through the outlet of the high-pressure pump, and a check valve that allows only the flow from the injection nozzle to the high-pressure pump to flow in parallel with the discharge valve ( And a high-pressure fuel passage (12) joined downstream of the discharge valve (14) and the check valve (13) and connected to the injection nozzle.
When the water supply pipe for injecting water during the high pressure fuel in the high pressure fuel passage does not act (30) and the connection point (4
0) A new high-pressure fuel passage (120) having a check valve (140) at the outlet of the high-pressure pump (10) in parallel with the high-pressure fuel passage to prevent backflow of fuel. Wherein the junction (400) of the new high-pressure fuel passage and the high-pressure fuel passage includes a connection (40) between the high-pressure fuel passage and the water supply pipe.
A fuel / water injection device provided at a downstream position of the fuel / water injection device. 2. A high pressure pump (10) for pumping fuel,
A discharge valve (14) that allows only the flow from the high-pressure pump to the injection nozzle (20) to pass through the outlet of the high-pressure pump, and a check valve that allows only the flow from the injection nozzle to the high-pressure pump to flow in parallel with the discharge valve ( And a high-pressure fuel passage (12) joined downstream of the discharge valve (14) and the check valve (13) and connected to the injection nozzle.
When the water supply pipe for injecting water during the high pressure fuel in the high pressure fuel passage does not act (30) and the connection point (4
0) A new high-pressure fuel passage (120) having a check valve (140) at the outlet of the high-pressure pump (10) in parallel with the high-pressure fuel passage to prevent backflow of fuel. Wherein the junction (410) of the new high-pressure fuel passage and the high-pressure fuel passage is provided upstream of a connection point (40) between the high-pressure fuel passage and the water supply pipe. Injection valve.