JPH06280682A - Water injector - Google Patents

Abstract

PURPOSE:To provide a water injection device of diesel engine which always injects water in the most proper condition to injection fuel so that an exhaust amount of NOx is few and the environmental pollution is low. CONSTITUTION:A water injection device for a diesel engine has a water forcing device 21 in water infusing paths 16, 17 between a water pump 18 and fuel valve, a controlling valve for controlling the infusion of water to the water forcing device, a controlling valve 16 provided in a water infusing path from the water forcing device to respective fuel valves and control devices 20, 22 for inputting signals of an engine rotational frequency detector, crank angle detector, pump rack detector, etc., to control water infusing paths 16, 17.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water injection device applied to fuel injection of a diesel engine.

[0002]

2. Description of the Related Art A conventional water injection device will be described with reference to FIG. In the figure, 1 is a fuel tank, 2 is a fuel supply pump, 3 is a fuel injection pump, 4 is a plunger, 5 is a plunger barrel, 6 is a discharge valve, 7 is a check pressure regulating valve, 8 is a fuel injection pipe, and 9 is a fuel valve. Main body, 10 is a nozzle, 11 is a needle valve, 1
2 is a needle valve sack portion, 13 is a check valve, 14 is a spring, 15 is a water injection pipe, 16 is a control valve, 17 is a water supply pipe, 18 is a water supply pump, 19 is a water tank, and 20 is a control device. Control the control valve (16).

Next, the operation of the conventional example will be described.
Generally, the fuel supplied from the fuel tank 1 to the fuel injection pump 3 via the fuel supply pump 2 is compressed by the plunger 4 to have a high pressure, and the discharge valve 6 is pushed open to open the fuel injection pipe 8
Is sent to the fuel valve main body 9 through. Then, the high-pressure fuel guided to the needle valve sack portion 12 through the oil passage in the fuel valve and the oil passage in the nozzle tip overcomes the urging force of the spring 14, pushes up the needle valve 11 and is injected from the injection hole 10 into the combustion chamber. It

The conventional water jet device shown in FIG.
In a diesel engine equipped with a fuel valve for injecting fuel and water from one injection valve, water is sent to the water passage in the needle valve sac portion 12 and the nozzle tip during a period other than the fuel injection period,
Water and fuel are mixed and injected into the cylinder, thereby lowering the combustion temperature in the cylinder even in large diesel engine compression ratio, in which efforts to control emissions of polluting gases such as NO _x.

Next, a method for measuring the amount of water fed into the fuel valve of the conventional example will be described. The fuel sac portion 12 after the injection and the oil passage communicating with the fuel sac portion 12 have a valve opening pressure P _R defined by the check pressure regulating valve 7 of the fuel injection pump or a residual pressure P _r or less due to the suction-back action of the discharge valve 6. Has become.

On the other hand, the water in the water tank 19 is supplied by the water supply pump 1.
8, the pressure is increased by a pressure higher than the valve opening pressure P _R or the residual pressure P _r . The control valve 16 disposed in the water injection pipe between the water supply pump 18 and the fuel valve is controlled by the control device 20 which inputs the operating condition of the engine, and is controlled during the period in which fuel of the fuel valve is not injected. Control valve 16
When the valve is opened, high-pressure water flows through the water injection pipe 15 and the water passage in the fuel valve body 9 to push open the check valve 13 and the check pressure adjusting valve 7, and to the water passage in the nozzle tip and the needle valve sack portion 12. Injected.

At this time, the amount of water injected as described above is controlled to an optimum amount in the oil passage and the fuel injection pipe of the fuel injection valve by changing the valve opening time of the control valve 16 by the control device 20. It Then, as described above, the water injected into the water passage in the nozzle tip and the needle valve sack portion 12 is appropriately mixed, and then the needle valve 11 is pushed up by the high pressure fuel pumped from the fuel injection pump and injected from the nozzle injection port 10. It Since the check valve 13 is closed at the time of fuel injection, the fuel does not flow back to the water supply passage.

However, it has been stated that the amount of water injected into the water passage in the nozzle tip and the needle valve sack portion is optimally controlled by changing the valve opening time of the control valve 16, but in the conventional water injection device this is done. Even if the amount of water injected is controlled by the above, the amount of water actually supplied changes slightly depending on the set pressure of the check pressure adjusting valve 7 of each cylinder of the fuel pump or the variation of the sucking back action of the discharge valve 6. Become. For this reason, there is a problem that the amount of water injected cannot always be optimally controlled and the amount of NO _x discharged cannot be minimized.

An object of the present invention is to solve the above problems of the conventional device and to provide a water injection device capable of injecting an optimum amount of water into each fuel valve without variation.

[0010]

A water injection device of the present invention is a diesel engine having a plurality of fuel valves for injecting fuel and water, and is commonly provided in a water injection path between a water pump 18 and the plurality of fuel valves. Water pump 21, a control valve 22 for controlling the inflow of water into the water pump, and a control valve 16 for controlling water injection between the water pump and the plurality of fuel valves. ,

The amount of water sent to the water pressure feeder 21 is controlled by the opening time of the control valve 22, and the total amount of water sent from the water pressure feeder 21 to the plurality of fuel valves in one cycle is the total amount of the water pressure feeder 21. The opening and closing of these control valves 16 and 22 is characterized by being controlled by information such as the engine speed, the engine crank angle, and the fuel pump rack that are incorporated in the control device 20.

[0012]

With the above-mentioned configuration, it is possible to inject an optimum and equal amount of water into each fuel valve of the engine.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIG. Since 1 to 19 are the same as the water injection device of the conventional example, description thereof will be omitted. Reference numeral 21 is a water pump, 22 is a control valve for controlling the injection of water into the water pump, and 23 is a throttle provided for maintaining a pressure difference between the water supply pressure and the water pump 21. . 24 is a piston, 25 is a spring, 26
Is a drain pipe, and 20 is a control device for controlling the opening and closing of the control valves 16 and 22, and data from the engine speed, crank angle, and pump rack detectors are input.

Next, the operation of the above embodiment will be described.
Since the fuel supply and its injection method are exactly the same as the conventional ones, the description thereof will be omitted, and here, the method of adjusting the water injection to the injection valve will be described. When the control valve 22 is opened by being controlled by the control device 20, the water whose pressure has been boosted by the water supply pump 18 passes through the water supply pipe 17 and the throttle 23 provided in the middle of the water supply pipe 18 and flows into the water pump 21. Piston 2
4 is pushed up and supplied to the water pump 21.

At this time, the pressure P _W in the water pressure transmitter is the spring 2
By adjusting the mounting length of No. 5, it is lower than the water supply pressure from the water supply pump 18, and the valve opening pressure P of the check pressure adjusting valve 7 is adjusted.
It is kept higher than _R and the residual pressure P _r in the fuel injection pipe. When the valve opening pressure of the fuel injection valve is P _O , there is a relationship of P _R <P _P <P _W <P _O between the above valve opening pressures. The throttle 23 is provided in order to maintain a pressure difference within a certain range between the water supply pressure and the water pressure feeder 21. When the control valve 22 is closed via the control device 20 after a predetermined time, the water supply of the required amount of water into the water pressure transmitter 21 is completed.

Next, of the control valves 16, the one for controlling the water injection for feeding the water to the first fuel valve is opened via the control device 20, and the water in the water pressure transmitter 21 is the water channel in the nozzle tip as described above. Since the pressure is set higher than the pressure in the fuel oil passage, the check valve 13 is pushed through the water passage in the fuel valve to be injected into the water passage in the nozzle tip and the fuel sack portion 12. Water injection into the second fuel valve is simultaneously performed by the control of the other control valve 16. At this time, the injection of water is ended by the seating of the piston 24, and the amount of water injection is not affected by the check pressure setting pressure of the cylinder corresponding to the fuel pump or the residual pressure in the fuel injection pipe or nozzle tip. A certain optimum amount is also injected into.

[0017]

Since the present invention is constructed as described above, 1
In those plurality comprising a valve for simultaneously injecting fuel and water pieces of the fuel valve per cylinder, since water is always optimal amount in each fuel valve is supplied, NO _x emissions less low pollution agencies Can be provided.

[Brief description of drawings]

FIG. 1 is a system configuration diagram according to a first embodiment of the present invention.

FIG. 2 FIG. 1 corresponding diagram of a conventional example

[Explanation of symbols]

16 ... Control valve, 20 ... Control device, 21 ... Water pump, 22 ... Control valve, 23 ... Throttle.

Claims (1)

[Claims] 1. In a diesel engine equipped with a plurality of fuel valves for injecting fuel and water, a common water pump (2) provided in a water injection path between the water pump (18) and the plurality of fuel valves.
1) and a control valve (2) for controlling the inflow of water into the water pressure transmitter.
2) and a control valve (16) for controlling water injection between the water pump and the plurality of fuel valves, and the water pump (2)
The amount of water sent to 1) is controlled by the opening time of the control valve (22),
The total amount of water sent from the water pressure transmitter (21) to the plurality of fuel valves in one cycle is the total volume in the water pressure transmitter (21), and the opening and closing of these control valves (16, 22) is the control device (20). A water injection device, which is controlled by information such as engine speed, engine crank angle, and fuel pump rack taken into the engine.