JP3212324B2 - Water injection unit injector device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art Diesel engines are widely used as prime movers because of their high thermal efficiency.
It was a major problem that CO ₂ , HC, NO _{X and the} like were contained in large amounts. Therefore referred for fuel valve for injecting water is added to the fuel for reducing the NO _X. A fuel valve designed to inject water at the same time as a conventional fuel and its system will be described with reference to FIG. FIG. 4 shows a conventional fuel,
It is a figure of a water injection device.

In FIG. 1, reference numeral 1 denotes a fuel valve main body, and 2 denotes a nozzle tip which is attached to a tip of the fuel valve main body 1. Reference numeral 3 denotes an injection hole formed at the tip of the nozzle tip 2. 4
Is a fuel inlet fitting which is attached to the fuel valve body 1. 5
Is a fuel oil passage in the fuel valve, 6 is a fuel oil passage in the presser foot, and 7 is a fuel oil passage in the nozzle tip. Reference numeral 8 denotes a needle valve sack, which is a space provided inside the valve seat of the needle valve of the nozzle tip 7. Reference numeral 9 denotes a needle valve that fits snugly into the hole of the nozzle tip 7 and contacts the valve seat.

A needle valve spring receiver 10 is provided at an upper end of the needle valve 9. A spring 11 presses the needle valve spring receiver 10 with a spring. Reference numeral 12 denotes a needle valve opening pressure adjusting hardware which receives the end of the spring 11 and changes the installation length of the spring 11, thereby changing the valve opening pressure of the needle valve 9. Reference numeral 13 denotes a water injection fitting provided on the fuel valve main body 1. Numeral 14 is a ball check valve provided at the end of the water injection fitting 13 to allow only the flow in the direction of entering the fuel valve. A check valve spring 15 pushes the ball of the ball type check valve. Reference numeral 16 denotes a water passage in the fuel valve which is bored through the fuel valve body 1 in the axial direction. Reference numeral 17 denotes a presser foot water passage which communicates with the fuel valve water passage 16. Reference numeral 18 denotes a water passage in the nozzle tip, which communicates the water passage in the presser foot with the needle valve sack portion 8.

Next, a fuel and water supply system for the fuel valve will be described. 21 is a fuel tank, 22 is a fuel supply pump, 23 is a fuel injection pump main body, 24 is a plunger barrel, 25 is a plunger, and 26 is a discharge valve, all of which are well-known components of a diesel engine fuel system. Omit. Reference numeral 27 is a type of check valve which is provided in the fuel injection pump main body 23 in parallel with the discharge valve 26 and allows only the flow toward the barrel side and leaves a constant residual pressure. The discharge valve 26 and the fuel inlet fitting 4 are connected by an injection pipe (not shown). 28 is a water tank which contains water. A water supply pump 29 is connected to the water tank 28. Reference numeral 31 denotes an electromagnetic valve, and reference numeral 30 denotes a water supply pipe which connects the electromagnetic valve 31 and the water supply pump 28. Reference numeral 32 denotes a water injection pipe which is a solenoid valve 31 and a water injection fitting 1.
3 is communicated. Reference numeral 33 denotes a controller which issues a signal for opening and closing the solenoid valve 31 in synchronization with the rotation of the crankshaft of the engine (not shown).

Next, the operation of the conventional example will be described. The fuel injection pump 22 pumps out the fuel in the fuel tank 21 and supplies it to the fuel injection pump 23. The fuel injection pump 23 pushes out the fuel as the plunger 25 advances and pushes up the discharge valve 26 to the fuel valve 1 via an injection pipe (not shown). The oil pressure that reaches the needle valve sack 8 via the fuel oil passage 5 in the fuel valve, the fuel oil passage 6 in the presser foot, and the fuel oil passage 7 in the nozzle tip is applied to the spring 1.
When the force of pushing the first needle valve 9 is exceeded, the needle valve 9 is pushed up and fuel is injected from the injection hole 3. In the fuel and water injection fuel valve, water is fed into the needle valve sack portion 8 and the fuel oil passage 7 in the nozzle tip at a time other than the fuel injection time to mix and inject the fuel and water.

The method of mixing water in the fuel valve will be described in detail. The needle valve sack after injection and the fuel oil passage and water passage communicating therewith have a residual pressure P defined by the equal pressure valve 27.
r. On the other hand, the water in the water tank 28 is pressurized by the water supply pump 29 to a pressure higher than the residual pressure Pr. When the solenoid valve 31 is opened by a signal from the controller 33, high-pressure water pushes up the check valve 14 from the water injection pipe 32 through the water injection fitting 13 and is injected into the fuel valve inner water passage 16. The amount of water injected at this time is determined by the time for opening and closing the solenoid valve 31 by the controller 33.

As described above, water mixes with the fuel oil remaining in the needle valve sack portion 8 and further pushes back the fuel by the amount of water to flow into the fuel oil in the fuel oil passage 7 in the nozzle tip and mix.
When the fuel oil is delivered from the fuel injection pump 23, the pressure reaches the needle valve sack portion 8 and when the pressure exceeds the force of the spring 11, pushes up the needle valve 9 to first raise the needle valve sack portion 8 and the fuel oil passage 7 in the nozzle tip. Fuel oil and water are injected from the injection hole 3, and then fuel is injected. The injection pressure flows backward in the water channel, but the check valve 1
Stopped at 4. Since the fuel valve 1 and the fuel injection pump 23 are connected by a long injection pipe (not shown), even if a large amount of water is injected, the fuel does not enter the injection pump.

The unit injector will be described with reference to FIG. FIG. 5 is a sectional view of a conventional unit injector. In the figure, 101 is a main body, 102 is a plunger barrel, 103 is a plunger, 104 is a fuel supply / discharge hole, 10
Reference numeral 5 denotes a plunger chamber, 106 denotes a fuel oil passage, 107 denotes a nozzle tip, and 108 denotes an injection hole formed at the tip of the nozzle tip 107. Reference numeral 109 denotes a needle valve, and reference numeral 110 denotes a needle valve spring which presses the needle valve 109 via a spring receiver. Reference numeral 111 denotes a fastener, which tightens and assembles each part in the axial direction. A tappet 113 is provided on the plunger 102. 1
Reference numeral 12 denotes a plunger spring, which is provided between the tappet 113 and the main body 101 by a pressing spring.

When the tappet 113 is pushed by a cam or the like (not shown), the plunger 102 moves forward, and the fuel supplied from the oil supply / discharge hole 104 to the plunger chamber 105 is closed by the plunger to compress the fuel, and then the fuel is compressed. Oil is needle valve 10
9 is ejected from the injection hole 108. This device is called a unit injector because it has a single plunger and nozzle tip, and is characterized by a short fuel oil passage, and is suitable for performing good high-pressure injection.

[0011]

However, since the water injection by the conventional injection device has a long fuel injection pipe even if a large amount of water is injected, the water reaches the sliding portion of the fuel pump plunger. And good water injection can be realized. However, having a long injection tube prevents high pressure injection. That is, there is a disadvantage that secondary injection and cavitation occur. If a unit injector without a fuel injection pipe is applied to water injection as it is to improve this, water will reach the sliding part of the plunger due to the short fuel oil passage, causing sticking and wear of the plunger, and the reliability of the engine will increase. There is a concern of losing sex.

An object of the present invention is to solve the above conventional apparatus, the plunger sliding portion is injecting fuel and water without putting the water, providing a water injection unit injector to reduce the emission of the NO _X The purpose is to:

[0013]

A water injection unit injector device according to the present invention has a check valve in a water supply passage, and a water supply in which an outlet side of the check valve joins a discharge fuel oil passage from a plunger. In a unit injector having a device,
A recess provided at the top of the plunger, and a clearance provided between the inner periphery of the peripheral wall of the recess and provided in the fuel injection valve.
An oil passage and a protrusion which is fitted so as to be relatively slidable, the open other end projecting provided on raised portion at one end said recess is connected to the fuel injection valve and a recess peripheral wall of the plunger And a communication hole that communicates between the recess and the plunger chamber.

[0014]

With the above arrangement, even if a large amount of water is injected, water accumulates in the plunger recess and does not reach the sliding portion between the plunger and the plunger barrel. Also, at the time of discharge, the oil in the plunger chamber is pushed out through the gap between the projection of the spring case and the concave portion of the plunger chamber, so that water does not flow into the sliding portion and seizure of the fuel injection pump does not occur.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment will be described with reference to FIG. FIG. 1 is a sectional view of a first embodiment according to the present invention. 1 in the figure
001 is the main body, 1002 is the plunger barrel and the main body 10
01 is supported. A plunger 1004 is fitted in the plunger barrel 1002. Reference numeral 1018 denotes a plunger chamber, which is formed on the inner periphery of the plunger barrel 1002 , the top surface of the plunger 1004 , and the upper part of the spring case 1008 of the fuel injection valve.
And a cylindrical space formed between them. An oil supply / drain hole 1003 provided in the plunger barrel 1002 communicates with the plunger chamber 1018. Reference numeral 1005 denotes a cylindrical recess provided at the tip of the plunger 1002.

Reference numeral 1006 denotes a communication hole which is a plunger recess 100.
5 is a hole that penetrates the peripheral wall of the concave portion of the plunger 1004 near the bottom of 5. Reference numeral 1007 denotes a step at the tip of the plunger, which is located at the same position as the bottom of the plunger recess 1005. The step is added here, and the outer diameter of the plunger beyond this is reduced. 10
Reference numeral 08 denotes a spring case which is provided in contact with the distal end surface of the plunger barrel 1002 and has a cylindrical shape. 100
Reference numeral 9 denotes a protrusion, which is provided on the top of the spring case 1008 and has a cylindrical shape protruding into the plunger chamber 1018 and is inserted with a gap into the plunger recess 1005. Reference numeral 3002 denotes a spacer provided in contact with the tip of the spring case 1008. Reference numeral 1010 denotes a fuel oil passage which penetrates the spring case 1008 vertically.

Reference numeral 1011 denotes a nozzle tip which is a spacer 300
2 is provided in contact with the tip of the second. Reference numeral 1012 denotes an injection hole formed at the tip of the nozzle tip 1011. 101
Reference numeral 4 denotes a needle valve that fits into the hole of the nozzle tip 1011 and contacts the valve seat at the tip. Reference numeral 1013 denotes a space provided inside the valve seat at the tip of the nozzle tip 1011 as a needle valve sack. The tip of the fuel oil passage 1010 penetrates the spacer 3002 and the nozzle tip 1011 in the axial direction and communicates with the needle valve sack 1013. Reference numeral 1015 denotes a fuel valve spring, which is a pressing spring which is inserted into the hollow portion of the spring case 1008 and presses the needle valve 1014 in the direction of the valve seat via a spring receiver. Reference numeral 1016 denotes a water passage that passes through the plunger barrel 1002, the spring case 1008, the spacer 3002, and the nozzle tip 1011 in the axial direction from the middle of the plunger barrel 1002 and communicates with the needle valve sack 1013. A check valve 1017 is provided in the water passage 1016 in the spring case 1008 and allows only the flow from the plunger barrel water passage 1016 toward the nozzle tip 1011.

The operation of the first embodiment will be described. When water is not injected, fuel flows into the plunger chamber 1018 from the oil supply / drainage hole 1003 in the retreat stroke of the plunger 1004, and when the step 1007 at the tip of the plunger closes the oil supply / drainage hole 1003 in the forward movement of the plunger, the plunger chamber 1018 When the pressure in the needle valve sack 1013 exceeds the force of the fuel valve spring 1015, the needle valve 1014 is pushed up and fuel is injected from the injection hole 1012. When the plunger 1004 is further advanced and the cutout of the oil reaches the oil supply / discharge hole 1003, the plunger chamber 10
The pressure 18 drops through the oil supply / discharge hole 1003, and the injection ends.
Thereafter, the pressure in the fuel oil passage is maintained at the residual pressure defined by the equal pressure valve.

When water is injected together with the fuel, water measured from a water supply device (not shown) is supplied to the water passage 1016 at a pressure higher than the residual pressure of the fuel oil passage. The supplied water pushes back the fuel in the fuel oil passage 1010 at the needle valve sack portion 1013, opens the check valve 1017, flows into the fuel oil passage 1010 from the needle valve sack portion 1013, and continues until the measured water has entered. Get into it. When the amount of water is large, when the fuel oil passage 1010 overflows, it enters the plunger recess 1005 and does not reach the sliding surface of the plunger. At the time of the water injection, the needle valve sack portion 1013, the fuel oil passage 1010, the recess 1
Since water enters about 1/2 of the volume of 005,
A sufficiently large amount of water can be injected with respect to the fuel injection amount. Also, at the time of such water injection, since the area of the communication hole 1006 is sufficiently large with respect to the fitting gap of the concave portion 1005, the fuel is flushed toward the communication hole 1006 side by the injected water, and sufficient fuel is injected into the concave portion 1005. The amount of water accumulates.

When the plunger 1004 moves forward during the injection stroke, the step 1007 at the tip of the plunger moves to the oil supply / drain hole 1003.
When the valve is closed, the backflow of the water channel is stopped by the check valve 1017, so that the pressure of the plunger chamber 1018 rises and the pressure is transmitted to the needle valve sack portion 1013, and finally the needle valve 1014 is pushed up.
Fuel or water in fuel oil passage 1010 and plunger recess 1
The fuel or water in 005 is injected from the injection hole 1012.
As the plunger 1004 advances, the fuel in the plunger chamber 1018 causes the protrusion 1009 and the plunger recess 1 to move.
005 through the gap and the communication hole 1006 to the fuel oil passage 1010. At the time of the above injection, the plunger chamber 1018 has a high pressure at the time of discharging the fuel, so that the water stored in the concave portion 1005 is pushed out to the fuel oil passage 1010 without entering the sliding surface of the plunger 1004.

A second embodiment will be described with reference to FIG. FIG.
Is a sectional view of the second embodiment. In the figure, 1001 to 1
018 is the same as in the first embodiment. In the figure, 2001
Is an annular path provided on the nozzle tip 1011 and provided with the needle valve 101.
Fuel oil passage 1010 which is sealed by the guide portion 4
And the water channel 1016. The operation of the second embodiment will be described. When the measured water is supplied from the water passage 1016, the water enters the fuel oil passage 1010 from the annular passage 2001, and the fuel in the fuel oil passage from the injection hole through the annular passage 2001 remains as it is. Therefore, at the time of the next injection, the nozzle tip 1011
The fuel remaining at the tip of the is injected earlier.

A third embodiment will be described with reference to the drawings. FIG. 3 is a sectional view of the third embodiment. In the figure, 1001 to 10
Reference numeral 18 is the same as in the first embodiment. In the figure, reference numeral 3002 denotes a spacer. 3001 is a confluence waterway with a spacer 300
A fuel oil passage 1010 and a water passage 1016 are provided at a joint between the nozzle tip 2 and the nozzle tip 1010. The operation of the third embodiment will be described. The measured water is supplied to the water passage 1016, the water passes through the check valve 1017, enters the fuel oil passage 1010 from the merging flow path 3001, and the fuel in the fuel oil passage on the nozzle tip 1011 side is kept closed to prevent the spring from entering. It enters the fuel oil passage on the case 1008 side. At the time of the next injection, the fuel remaining in the nozzle tip 1011 is injected earlier.

[0023]

According to the present invention, a large amount of water can be simultaneously injected with fuel without water flowing into the sliding portion of the plunger in a unit injector in which secondary injection and cavitation do not occur and high pressure injection can be easily realized. Thereby emissions of the plunger stick and high water injector of the wear-free reliability can be provided NO _X is reduced can be provided a small engine of pollution. Thus the invention is not to put water into the plunger sliding portion, it is possible to provide a water jet unit injector to reduce the emission of stably inject fuel and water NO _X.

[Brief description of the drawings]

FIG. 1 is a sectional view of a first embodiment according to the present invention.

FIG. 2 is a sectional view of a second embodiment according to the present invention.

FIG. 3 is a sectional view of a third embodiment according to the present invention.

FIG. 4 is a diagram of a conventional fuel water injection device.

FIG. 5 is a diagram of a conventional unit injector.

[Explanation of symbols]

 1001 Body 1004 Plunger 1005 Plunger recess 1006 Communication hole 1007 Step at plunger tip 1009 Projection 1010 Fuel oil passage 1013 Needle valve sack 1016 Water passage 1017 Check valve

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) F02M 43/00 F02M 43/02 F02M 43/04 F02M 25/022 F02M 57/02 330

Claims (1)

(57) [Claims] 1. A unit injector having a check valve in a water supply passage, and a water supply device in which an outlet side of the check valve joins a fuel oil passage discharged from the plunger, the unit injector being provided at a top of the plunger. A projection provided on the fuel injection valve, the projection being fitted in the recess so as to be slidable relative to the inner circumference of the peripheral wall of the recess, and provided on the projection. It is by one end becomes comprises a fluid passage opening and the other end connected to the fuel injection valve into the recess, and a contact hole is drilled in the recess peripheral wall of the plunger communicating with the recess and the plunger chamber A water injection unit injector device characterized by the above-mentioned.