JP3165502B2 - Diesel engine fuel injection system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art A conventional fuel injection device (hereinafter referred to as a two-fluid injection device) for injecting fuel and water from one fuel valve is described.
An example will be described with reference to FIG. FIG. 5 is an explanatory view of a conventional device for injecting fuel and water from one fuel valve. Diesel engines are used as prime mover in various fields widely because of high increased thermal efficiency compression ratio, but harmful CO in the exhaust gas component, CO 2, _HC, this since containing a large amount of NO _x, etc. Reduction is a major issue. Here referred for conventional type 2 fluid ejection device that performs water injection into the combustion chamber which is effective in reducing NO _x. In the figure, 1 is a fuel valve , 2 is a tip of a nozzle, 3 is an injection hole, and 4 is a fuel inlet fitting which is well known. 5 is a fuel oil passage in the fuel valve, 6 is a fuel oil passage in the presser foot, 7 is a fuel oil passage in the nozzle tip, 8 is a needle valve sack portion, 9 is a needle valve, 10 is a needle valve spring receiver, and 11 is a needle valve. The spring 12 adjusts the valve opening pressure of the needle valve 9 by changing the installation length of the needle valve spring 11 with a valve opening pressure adjusting hardware of the needle valve.

Reference numeral 13 denotes a water injection metal fitting, 14 denotes a ball type check valve, 15 denotes a check valve spring, 16 denotes a fuel valve inner water path, 17 denotes a presser foot inner water path, and 18 denotes a nozzle tip inner water path. The fuel oil passage 7 in the nozzle tip and the water passage 18 in the nozzle tip join at the needle valve sack portion 8. Next, another fuel system configuration will be described. 23 is a fuel injection pump, 21 is a fuel tank, 22 is a fuel supply pump and the suction port is the fuel tank 21
The outlet is connected to the fuel injection pump 23. 2
4 is a plunger barrel, 25 is a plunger, 26 is a discharge valve, and 27 is a constant pressure valve, all of which are elements of the fuel injection pump 23. The discharge part of the fuel injection pump 23 and the fuel inlet fitting 4 are connected by an injection pipe.

[0004] 28 is a water tank, 29 is a water supply pump, 3
0 is a water supply pipe, 31 is a solenoid valve, 32 is a water pipe and a solenoid valve 31
And the water injection fitting 13 are connected. A controller 33 controls the solenoid valve 31 and the like, and controls a valve opening timing and a valve opening period by a signal synchronized with a crankshaft of an engine (not shown). Reference numeral 34 denotes a rack drive unit, which is a controller 3
3 to move a rack (not shown) of the fuel injection pump 23.

The operation of the conventional example will be described. When injecting only fuel, the fuel stored in the fuel tank 21 is pumped up by the fuel supply pump 22 and supplied to the fuel injection pump 23. The fuel injection pump 23 pushes the fuel oil supplied into the barrel 24 with the plunger 25 to open the discharge valve 26 and push the fuel oil from the fuel inlet fitting 4 into the fuel valve 1 through the injection pipe, thereby causing the fuel oil passage 5 in the fuel valve and the presser fitting to move. It is pushed into the needle valve sack portion 8 through the internal fuel oil passage 6 and the oil passage 7 in the nozzle tip. When the pressure in the needle valve sack 8 acts on the needle valve 9 and the pressure exceeds the force of the needle valve spring 11, the needle valve 9 is pushed up, the injection hole 3 is opened, and the injection is performed from the injection hole 3. After the injection is over, fuel valve 1
All of the fuel oil passage and conduit leading to leading to the fuel injection pump from being kept at a residual pressure P _x which is determined by the constant pressure valve 27.

When water is injected together with the fuel, the water is
Inject into fuel valve 1 . At this time, the water in the water tank 28 is pumped by the water pump 29 and is raised to a pressure higher than the valve opening pressure of the constant pressure valve 27. At a certain time between the fuel injection and the next fuel injection, the EKEN valve 31 is opened for a certain time under the control of the controller 33, and water is supplied from the solenoid valve 31 to the water pipe 3 during the said time.
2. The ball-type check valve 14 is opened via the water injection hardware 13 to open the fuel valve inner water passage 16, the presser foot inner water passage 17, the nozzle chip inner water passage 18 to the needle valve sack portion 8, and further merges into the fuel oil passage. The fuel oil is pushed out and injected. Therefore, the constant pressure valve 27 is opened and mixed from the oil passage 7 in the nozzle tip to the oil passage 6 in the presser foot and the oil passage 5 in the fuel valve depending on the amount of water. The amount of water injected is determined by the time the solenoid valve 31 is open by the controller 33. The water mixed into each fuel oil passage is injected together with or pushed by the fuel at the time of the next fuel injection. The ball check valve 14 flows backward to stop the fuel injection pressure from reaching the water supply system. At the time of water injection, the fuel is reduced by the amount of water as it is. Therefore, the rack is pushed in through the rack drive unit 34 under the control of the controller 33, and the stroke of the plunger is increased by the amount of water injection to correct the decrease in the fuel injection amount. The position of the rack is shown in FIG. 2, the vertical axis represents the rack position, and the horizontal axis represents the engine load.

[0007]

The above prior art has the following disadvantages. Even if the water injection operation is continued and the water runs out, or if a failure occurs in the water supply system and the supply of water to the fuel valve is stopped, the rack position of the fuel injection pump 23 remains at the time of the water injection operation. Fuel corresponding to the injection amount is added and injected. Therefore, not only the amount of fuel is too large, but also the exhaust gas characteristics such as the exhaust color deteriorate, and also the engine itself may be damaged by excessive heat load during high load operation. SUMMARY OF THE INVENTION An object of the present invention is to provide a fuel injection device for a diesel engine in which proper fuel is injected even when water is not injected into a fuel valve due to exhaustion of water or failure of a water supply system due to the above-mentioned problems. It is to be.

[0008]

The fuel injection system of the means for solving the problems] diesel engine according to the first means, supply water to the injection pipe and the fuel injection pump a fuel injection pump having a constant pressure valve (27) (23) (23) Water pump (29) and the water pump (2
Solenoid valve which enables metered amount of water supply from 9) and (31) made of <br/>, by adding the supply amount of the water to the fuel injection amount rack position of the fuel injection pump (23) and sets, in which the fuel and water simultaneously jettable configured in the cylinder with one injection valve (1), the water tank (2
8) Water quantity detection sensor (35) that operates at the low level position
When the injection valve when the missing water signal of the water tank (28) water amount sensor (35) is operated is generated
(1) A controller (33) for stopping supply of water to the fuel injection pump (23) and controlling the rack of the fuel injection pump (23) to return to a position where water injection is not performed. Fuel injection of diesel engine according to the second means
The apparatus according to the first means, wherein the controller (33)
The position for taking out the water shortage signal from the water tank (28) is replaced with the water supply path (16), and the water amount detection sensor (3)
5) is changed to an in-water pressure sensor (37). Diesel engine fuel injection according to the third means
The device is characterized in that, in the first means or the second means , an alarm device (36) for issuing an alarm immediately when the water shortage signal is generated.

According to the first means or the second means, when it less water in the water tank, supply of Oite water before the water is eliminated is stopped, if the rack position of the fuel injection pump is not water injection Return to the position and adjust the fuel injection amount to an appropriate value .
Can be According to the third means, when the water is used up, or when water injection to the injection valve is not performed suddenly due to malfunction of the water injection system, the shortage of the pressure in the water channel is detected by the pressure sensor in the water channel. When detected, an alarm is issued immediately, and the rack of the fuel injection pump returns to the position where water injection is not performed, so that an excessive amount of fuel is not injected.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment will be described with reference to FIGS.
FIG. 1 is a configuration diagram of a fuel injection device according to an embodiment, and FIG. 2 is a diagram illustrating a relationship between a load during two-fluid injection and a rack position of a fuel injection pump. In the figure, 1 is a fuel valve , 2 is a nozzle tip,
Reference numeral 3 denotes an injection hole, and 4 denotes a fuel inlet fitting. 5 is a fuel oil passage in the fuel valve, 6 is a fuel oil passage in the presser foot, 7 is a fuel oil passage in the nozzle tip, 8 is a needle valve sack portion, 9 is a needle valve, 10 is a needle valve spring receiver, and 11 is a needle valve. The spring 12 is a metal fitting for adjusting the valve opening pressure of the needle valve, and changes the installation length of the needle valve spring 11. 13 is a metal fitting, 14 ball check valve, 15 is a check valve spring, 16 is a water passage in the fuel valve,
Reference numeral 17 denotes an inner water passage of the presser foot, and reference numeral 18 denotes an inner water passage of the nozzle tip. The fuel oil passage 7 in the nozzle tip and the water passage 18 in the nozzle tip join at the needle valve sack portion 8. Reference numeral 23 denotes a fuel injection pump, which is provided with a rack (not shown). 21 is a fuel tank.
A fuel supply pump 22 is provided between the fuel tank 21 and the fuel injection pump 23. Reference numeral 24 denotes a plunger barrel, and reference numeral 25 denotes a plunger fitted to the plunger barrel 24. 26 is a discharge valve, 27 is a constant pressure valve and the injection pump 23
Is the element.

The discharge port of the fuel injection pump 23 is connected to the fuel inlet fitting 4 by an injection pipe. 28 is a water tank,
29 is a water supply pump, 30 is a water supply pipe, and 31 is an electromagnetic valve connected to the water supply pump 29 by the water supply pipe 30. Reference numeral 32 denotes a water pipe connecting the solenoid valve 31 to the water injection fitting 13. A controller 33 controls the solenoid valve 31, the rack driving device 34, and the alarm device 36. Reference numeral 34 denotes a rack driving device for moving a rack (not shown) of the fuel injection pump 23. Reference numeral 35 denotes a sensor for detecting the amount of water in the water tank.
3 for detecting the water surface in the water tank 28. Although the embodiment is a float type, another type may be used. Reference numeral 36 denotes an alarm device which is connected to the controller 33 and is shown as a lamp, but may be a buzzer or the like.

The operation of the first embodiment will be described. The description of the operation of the known elements of the above embodiment is omitted. When the amount of water in the water tank 28 during the operation by water injection decreases and falls below a set level, the water tank water amount detection sensor 35 detects this. The controller 33 stops the operation of the solenoid valve 31 according to the detection item of the water amount detection sensor 35 and operates the rack driving device 34 to move the position of the rack (not shown) of the fuel injection pump 23 to a position where water is not injected. In addition to injecting an appropriate amount of fuel according to the return driving load, the alarm device 36 is operated to notify the driver of the water shortage.

A second embodiment will be described with reference to FIGS. The second embodiment is different from the first embodiment in that a water supply pressure sensor is provided in the water supply passage instead of the water tank water amount detection sensor 35 of the first embodiment. explain. Reference numeral 37 denotes a pressure sensor in the water passage provided in the water passage 16 in the fuel valve and connected to the controller 33. Only the parts where the operation of the second embodiment is different from that of the first embodiment will be described. When the pressure in the water channel during the water injection period set by the water channel pressure sensor 37 is detected, and the detected pressure is less than the set pressure between the opening pressure of the equal pressure valve 27 and the water supply pressure as shown in FIG. That is, when water is no longer supplied to the fuel valve 1 , the controller 33 issues an alarm via the alarm device 36. In this embodiment, the lamp is turned on and the rack driving device 34 is operated to return the rack of the fuel injection pump 23 to the position where water is not injected as shown in FIG. As a result, injection of an excessive amount of fuel into the cylinder can be prevented, and an appropriate amount of fuel can be injected according to the load.

[0014]

According to the present invention, in a two-fluid injection device for injecting fuel and water , when the amount of water in the water tank decreases , the supply of water is stopped before the water runs out,
Rack position of the fuel injection pump when water injection is not performed
By returning to, the fuel injection amount can be set to an appropriate value.
If the injection of water into the injection valve is suddenly stopped due to a malfunction of the water supply system as in claim 3 , an alarm is immediately issued to notify the driver of the abnormality and to alert the driver. excessive amount of it is possible to prevent the fuel injection, thereby combustion having stable good low NO reduction of exhaust emissions and low fuel consumption characteristics of _X was obtained. Thus, according to the present invention ,
It is possible to provide a fuel injection device for a diesel engine in which an appropriate amount of fuel is injected even when water is no longer injected due to water exhaustion or an accident.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a fuel injection device according to a first embodiment.

FIG. 2 is a diagram illustrating a relationship between a load of a two-fluid ejection device and a rack position.

FIG. 3 is a configuration diagram of a fuel injection device according to a second embodiment.

FIG. 4 is a diagram showing a water injection timing and a water channel pressure detection period according to a second embodiment.

FIG. 5 is a configuration diagram of a conventional fuel injection device.

[Description of Signs] 1 ... fuel valve , 16 ... water passage in fuel valve, 21 ... fuel tank 23 ... fuel injection pump, 28 ... water tank, 31 ...
Solenoid valve 33 Controller, 34 Rack driving device 35 Water sensor in water tank, 36 Alarm device 29 Water pump 27 Pressure equalizing valve

Continuation of the front page (56) References JP-A-63-9639 (JP, A) JP-A-3-279666 (JP, A) JP-A-56-139859 (JP, U) JP-A-63-28861 (JP) , U) Japanese Utility Model Application Hei 1-29253 (JP, U) Japanese Utility Model Application Hei 3-122264 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) F02M 43/00 F02M 43/02 F02M 43/04 F02M 25/02 F02D 19/12 F02B 47/02

Claims (3)

(57) [Claims] 1. A like valve (27) supplying water from the fuel injection pump (23) and said fuel injection pump (23) for supplying water pump water into the injection pipe (29) water pump having a (29) amounts become more and quantifiable and the solenoid valve (31), along with by adding the supply amount of the water to the fuel injection amount to set the rack position of the fuel injection pump (23), one injection valve ( in those fuel and water simultaneously jettable configured in the cylinder 1), and water detection sensor operating at a low level position of the water tank (28) (35), the water amount sensor (35) is activated the rack stops supplying the water to the injection valve (1) and said fuel injection pump (23) is controlled so as to return to a position not to water injection when the missing water signal of the water tank (28) has occurred Having a controller (33) Diesel engine fuel injection system. 2. A position for taking out a water shortage signal to said controller (33) is replaced by a water supply path (16) from a water tank (28), and said water amount detection sensor (35) is replaced by an in-water pressure sensor (37). ).
A fuel injection device for a diesel engine as described in the above. 3. A comprising a warning device (36) for issuing an alarm in real when the missing water signal is generated according to claim 1 or 2
A fuel injection device for a diesel engine as described in the above.