JPH06123255A - Water injection diesel engine - Google Patents

Abstract

PURPOSE:To reduce NOx without causing any instability in operation of an engine due to burning failure even though injection amount is increased considerably by injecting fuel and water multi-layerdly. CONSTITUTION:By injecting water into the inside of a fuel passage 22 of a fuel injection valve 40 while fuel is not emitted from a fuel injection pump 3, both of fuel and water are injected into the inside of the cylinder by means of the single fuel injection valve 40. Herein, plural water supply pipes 151, 152 in which water injection electromagnet valves 161, 162, which are connected to a water supply source and control a water injection amount and a water injection duration are interposedly installed, while plural junction parts 311, 312 of injected water from the water supply pipes 151, 152 and fuel inside the fuel passage 22 are installed on the upstream side of the fuel passage 22 in order, by setting the closest upstream part of an oil sump 12 in the fuel injection valve 40 as the starting point. In addition, water injection into the fuel passage 22 is carried out in due order from the closest position to the oil sump 12 to the upstream side, or from the farthest position thereto to the downsteam side, so that fuel and water are formed in a multi-layer liquid column.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to water injection diesel engines.

[0002]

Reducing the nitrogen oxides NO _x contained in the exhaust gas of the Related Art Diesel engines, as a means of achieving together also reduce the exhaust black smoke and fuel consumption rate at the same time, the fuel and water from the same fuel injection valve It is said that a water injection diesel engine that injects into the cylinder is effective. Fig. 5 shows the fuel of a water injection diesel engine according to the prior art.
The configuration of the water injection device is shown. The configuration 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, and 7 is a check valve provided in a side passage of the discharge valve 6. A pressure valve, 8 is a fuel injection pipe, 40 is a fuel injection valve, 9 is the same body, 10 is an injection hole, 11 is a needle valve, 12
Is an oil reservoir, and 14 is a biasing spring of the needle valve 11.

Further, 19 is a water tank, 18 is a water supply pump, 17 is a water supply pipe (pump side), 16 is a water injection electromagnetic control valve, 15 is a water supply pipe (injection valve side), and 13 is the reverse of injected water. The stop valve prevents water from flowing back to the control valve side. Reference numeral 20 is a control device for controlling the amount and timing of water supply, which inputs a crank angle signal of the engine and signals of other engine operating conditions, and outputs an opening / closing signal to the electromagnetic control valve 16 via a line 23. The fuel passage 2 is provided in the main body 9 of the fuel injection valve 40.
2 is perforated and connects the fuel injection pipe 8 and the oil sump 12. Further, the body 9 of the injection valve 40 has a water injection passage 21
Is provided with a check valve 13 in the middle of the flow passage, and communicates with a confluence portion 31 in the middle of the fuel passage 22 via a water passage 30 formed in a downstream portion of the flow passage. There is.

Next, the operation of the above configuration will be described. The water pumped from the water tank 19 by the water supply pump 18 is sent to the electromagnetic control valve 16 through the water supply pipe 17, and during the rest period when the fuel injection pump 3 is not pumping fuel, the electromagnetic control valve 16 is kept open for a predetermined period of time via the control device, and a predetermined amount of water is fed into the water injection passage 21 of the fuel injection valve 40 via the water supply pipe 15. At that time, the valve opening pressure of the check pressure regulating valve 7 of the fuel injection pump 3 is P _R , the valve opening pressure of the water injection check valve 13 is P _P , the needle valve 1
Assuming that the valve opening pressure of No. 1 is P _O , P _O > P _p > P _R , so the injected water passes through the water injection check valve 13, and passes from the water passage 30 through the confluence portion 31 to the fuel passage. It flows into 22. Due to this injected water pressure, the fuel on the upstream side of the confluence portion 31 in the fuel passage 22, that is, on the fuel injection pump 3 side is pushed back in the injection pipe 8 toward the injection pump 3.
The check pressure regulating valve 7 is pushed open to flow back into the plunger barrel.

The resulting situation is shown in the detailed configuration diagram of the fuel injection valve of FIG. In the fuel injection valve 40, the volume V ₂ of the oil sump 12 and the volume V ₁ of the fuel passage 22 from the junction 31 to the oil sump 12 are the sum of (V ₁ + V ₂ ) The fuel passage 22 on the upstream side of the merging portion 31 is filled.
The inside of the fuel passage 22 is filled with a predetermined amount of water, and the fuel passage 22 upstream thereof is filled with fuel again. Next, when the plunger 4 of the fuel injection pump 3 rises to pressurize the fuel, the fuel injection pipe 8, the fuel passage 22 and the oil sump 1
When the pressure in 2 rises and becomes equal to or higher than the valve opening pressure P _O of the needle valve 11, the needle valve 11 is opened. At this time, the water in the water passage 30 is not pushed back to the electromagnetic control valve 16 side by the action of the check valve 13.

When the fuel pressure exceeds the valve opening pressure P _O of the needle valve 11, the above-mentioned (V ₁ + V ₂ ) volume of fuel is first injected from the injection hole 10, and then a predetermined amount is injected. Water is injected, and finally the remaining fuel is fully injected. That is, assuming that the amount of total injected fuel in one cycle is Q _F , first, as shown in FIG. 7, Q _FP = (V ₁ + V ₂ )
Is injected with a certain amount of fuel, and then the total amount of water Q _W
Is injected, and the remaining fuel quantity is Q _FS , Q _FS = Q _F −
Q _FP will be injected last. As a result, first Q
The fuel injection of _FP ensures the ignition in the early stage of the combustion process, and the subsequent injection of water of Q _W increases the introduction of air into the fuel spray, increasing the combustion speed and reducing the generation of black smoke. it is possible to reduce of the NO _X by the introduction of water into Rutotomoni combustion zone.

[0007]

However, the above-mentioned conventional technique has the following problems. That is, the effect of reducing NO _X contained in the exhaust gas is obtained almost in proportion to the water injection amount Q _W , but if the water injection amount Q _W is excessively increased relative to the total fuel injection amount Q _F , the The injection time interval between the initial injection amount Q _FP and the late injection amount Q _FS becomes too wide, resulting in poor combustion and unstable engine operation. Therefore, in order to obtain the NO _X reduction effect, it is necessary to take a method capable of increasing the water injection amount Q _W without causing combustion failure.

The object of the present invention is to solve the above-mentioned problems of the prior art and to construct a structure in which fuel and water are injected in multiple layers in a cylinder, so that even if the injection amount of water is increased, poor combustion occurs. (EN) Provided is a water-injection diesel engine capable of significantly reducing NO _X contained in exhaust gas in response to an increase in the amount of water injection without causing instability in engine operation due to.

[0009]

In the water injection diesel engine according to the present invention, by injecting water into the fuel passage 22 of the fuel injection valve 40 during a period in which fuel is not being discharged from the fuel injection pump 3, In a water injection diesel engine configured to inject fuel and water into a cylinder with one fuel injection valve 40, water injection solenoid control valves 161 and 162 connected to a water supply source and controlling the injection amount and injection timing of water.
A plurality of water supply pipes 151, 152 in which the water is inserted are provided, and confluence portions 311 and 312 of the water injected from the respective water supply pipes 151 and 152 and the fuel in the fuel passage 22 are connected to the oil sump 12 of the fuel injection valve. A plurality of them are sequentially installed on the upstream side of the fuel passage 22 starting from the immediately upstream portion thereof, and water is injected into the fuel passage 22 from the portion closest to the oil sump 12 to the upstream side.
Alternatively, it is characterized in that the fuel and water are formed into a multi-layered liquid column in sequence from the furthest part to the downstream side, and the injection water in one cycle is controlled so as to completely complete the injection in the cycle. There is.

[0010]

When the first water injection electromagnetic control valve 161 is opened for a predetermined time during the period in which fuel is not being discharged from the fuel injection pump 3, the first water supply pipe 151 causes the fuel injection valve 40 to open.
A predetermined amount of water is injected into the water injection passage 211. The injected water opens the check valve 131 by the water pressure, and the water passage 30
To the fuel passage 22 through the merging portion 311 to open the check pressure regulating valve 7 and push the residual fuel of the previous cycle filling the upstream side of the fuel passage 22 back into the injection pump and To be filled. When the water injection from the first water injection system is completed, the water injection electromagnetic control valve 161 is closed, and
The electromagnetic control valve 162 of the water injection system is opened. Next, the water sent from the second water supply pipe 152 is injected into the merging portion 312 by opening the check valve 132 from the water injecting passage 212, and the fuel passage 22 upstream of the merging portion is completely filled. The non-return pressure regulating valve 7 is opened to push back the remaining fuel, and the fuel is pushed back into the injection pump to fill the fuel passage 22 with water. When the filling is completed, the electromagnetic control valve 162 is closed.

As a result, in the fuel passage 22, the fuel remaining in the fuel passage after the completion of the injection in the previous cycle and the water injected from the two sets of water injection systems flow from the oil sump 12 side to the upstream side. Alternate multilayer liquid columns are formed in the order of (fuel)-(water)-(fuel)-(water)-(fuel). When a larger number of water injection systems are provided, an arbitrary number of multi-layered fuel and water liquid columns can be formed in the fuel passage by the same configuration and operation as described above.

When the fuel injection pump 3 operates in this state, the liquid column maintains its multi-layer structure and the fuel injection valve 40
It is injected into the cylinder from the injection hole 10 of. As a result, even if the water injection amount Q _W is greatly increased as compared with the conventional example, the water and the fuel are injected in a multi-layered manner, so that no defective combustion occurs. Thus increasing the water injection amount without causing the operating instability of the engine becomes possible, the generation of the NO _X when burned in response to increase of the water injection amount can be significantly reduced.

[0013]

1 shows the structure of a fuel / water injection device for a water injection diesel engine according to an embodiment of the present invention. The names and functions of the reference numerals 1 to 31 in FIG. 1 are the same as those in the conventional example shown in FIG. 5 as the configuration according to the conventional technique, and therefore description thereof will be omitted, and the components added in this example will be described. The water tank 19 and the water supply pump 18 have a common structure with two sets of water injection systems.
The water supply pipe 17 from the pump is branched into two, and a separate water injection system is constructed from the downstream portion thereof.

Numerals 161 and 162 are water injection electromagnetic control valves 231 and 232 to which the water supply pipes branched into the above two are connected.
Is a line from the control device 20 to both solenoid control valves, 1
51 and 152 are water supply pipes, 211 and 212 are water injection passages,
Injected water check valves 131 and 132 are provided in both water injection passages, and 311 and 312 are junction portions of the injected water and the fuel in the fuel passage 22. Confluence part 312 of the second water injection system
Is a first merging portion 311 provided in the fuel injection valve 40.
A space corresponding to a certain volume in the fuel passage 22 between
In addition, the fuel passage is provided on the side farther from the oil sump 12 upstream of the confluence portion 311.

Next, the operation of the embodiment having the above construction will be described. During the period in which fuel is not being discharged from the fuel injection pump 3, first, when the water injection electromagnetic control valve 161 of the first water injection system is opened by the control of the control device 20, a predetermined amount of water is generated as in the conventional example. It is sent from the water supply pipe 151 to the water injection passage 211 of the injection valve 40. The injected water pushes open the water injection check valve 131 and flows into the fuel passage 22 from the water passage 30 through the confluence portion 311. Due to this water pressure, the residual fuel of the previous cycle filling the upstream side of the confluence portion 311 in the fuel passage 22, that is, the fuel injection pump side is pushed back toward the injection pump, and the check pressure regulating valve 7 is pushed open to open the plunger. Water flows back into the barrel and the fuel passage 22 is filled with water.

Next, under the control of the control device 20,
The electromagnetic control valve 161 of the first water injection system is closed and the electromagnetic control valve 162 of the second water injection system is opened. As a result, the water sent from the second water supply pipe 152 pushes the check valve 132 out of the second water injection passage 212 and is injected into the merging portion 312, and is upstream of the merging portion 312 in the fuel passage 22. That is, the residual fuel of the previous cycle on the fuel injection pump side is pushed back to the injection pump side by opening the check pressure regulating valve 7 and the fuel passage 22 is filled with water. When the filling of water is completed, the electromagnetic control valve 162 is closed. Water injection solenoid control valve 1
The operating conditions of 61 and 162 are shown in FIG. As a result, in the fuel passage 22, the oil sump 12 and the water passage 3 upstream thereof are
The remaining fuel is filled up to the lower part of the merging portion 311 with 0, the predetermined amount of water injected from the first water injection system is filled upstream of the merging portion 311, and the upstream side is filled with the predetermined amount of water. The area up to the confluence section 312 of 2 is filled with residual fuel,
A predetermined amount of water injected from the second water injection system is filled on the upstream side of the merging portion 312, and the upstream side thereof is a residual fuel pipe line connected to the fuel injection pipe 8. Therefore, alternating multi-layered liquid columns are formed in the fuel passage 22 in the order of (fuel)-(water)-(fuel)-(water)-(fuel) from the oil sump 12 to the upstream side. Here, it is assumed that the water is injected into the fuel passage 22 in order from the confluence portion 311 near the oil sump 12 to the upstream side 312. Pillars can be formed in the fuel passages.

When the fuel injection pump 3 operates and the fuel pressure exceeds the opening pressure P _O of the needle valve 11, the needle valve rises and opens the valve seat, but the check valves 131 and 132 inject the fuel. The generated water is not pushed back toward the water inlets 211 and 212. When the needle valve 11 is opened, the fuel and water formed in multiple layers in the fuel passage 22 are alternately injected into the cylinder. This injection situation is shown in FIG. After the injection is completed, the fuel passage 22 is filled with the fuel, including the oil sump 12, without water retention. The water injection system is filled with water on the upstream side of the merging portions 311 and 312. As shown in FIG. 3, fuel and water are alternately injected into the cylinder in multiple layers, so that the amount of water injected into the spray is greatly increased in order to reduce NO _X contained in the exhaust gas. , There is no risk of unstable combustion in the cylinder.

Regarding the embodiment shown in FIG. 1, it has been described that in the structure having two sets of water injection systems, water is injected into the fuel passage in order from the portion near the oil sump 12 to the upstream side. As shown in the drawing, even when the number of water injection systems is further increased to n, even when the order of water injection into the fuel passage 22 is sequentially performed from the portion distant from the oil sump 12 to the downstream side,
A liquid column in which more layers of fuel and water are alternately arranged is formed in the fuel passage 22 by a similar configuration and corresponding control,
More multi-layered injections as shown in FIG. 4 can be obtained, and a larger effect can be expected.

[0019]

INDUSTRIAL APPLICABILITY According to the present invention, in a water injection diesel engine in which fuel and water are injected from one fuel injection valve, the fuel and water are injected in multiple layers, so that the injection amount of water is significantly increased. Even if it is done, since water and fuel are injected in multiple layers, there will be no bad combustion. Therefore, it becomes possible to increase the water injection amount without causing instability of the engine operation, and it is possible to significantly reduce the NO _x generated during combustion in accordance with the increase in the water injection amount.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a fuel / water injection device of a water injection diesel engine according to an embodiment of the present invention.

FIG. 2 is an explanatory view of an operating state of the water injection electromagnetic control valve in FIG.

FIG. 3 is an explanatory view of a fuel-water injection state of a two-layer structure of injected water in FIG.

FIG. 4 is an explanatory view of the fuel-water injection state with a configuration in which even the n-th water injection electromagnetic control valve in FIG.

FIG. 5 is a configuration diagram of a fuel / water injection device of a water injection diesel engine according to the related art.

FIG. 6 is a detailed configuration diagram of a fuel injection valve in FIG.

7 is an explanatory view of the fuel-water injection state in FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Fuel tank, 3 ... Fuel injection pump, 6 ... Fuel discharge valve, 7 ... Check pressure regulating valve, 8 ... Fuel injection pipe, 9 ... Fuel injection valve main body, 10 ... Injection hole, 11 ... Needle valve, 12 ... Oil Pool, 17 ...
Water supply pipe, 19 ... Water tank, 20 ... Control device,
22 ... Fuel passage, 30 ... Water passage, 40 ... Fuel injection valve, 1
31, 132 ... Check valve, 151, 152 ... Water supply pipe, 1
61, 162 ... Electromagnetic valve for water injection, 211, 212 ... Water injection passage, 231, 232 ... Line, 311, 323 ... Joining section.

Claims (1)

[Claims] 1. A fuel passage (2) of a fuel injection valve (40) during a period in which fuel is not being discharged from the fuel injection pump (3).
2) In the water injection diesel engine configured to inject fuel and water into the cylinder with one fuel injection valve (40) by injecting water into the inside, a water injection amount connected to a water supply source And a water supply pipe (15) in which electromagnetic solenoid valves (161) and (162) for controlling the injection timing are provided.
1) and (152) are provided, and water injected from the water supply pipes (151) and (152) and the fuel passage (2) are provided.
A plurality of merging portions (311) and (312) with the fuel in 2) are sequentially installed on the upstream side of the fuel passage (22) starting from the immediately upstream portion of the oil sump (12) of the fuel injection valve. Water injection into the fuel passage (22) is sequentially performed from the portion closest to the oil sump (12) to the upstream side or from the farthest portion to the downstream side to form fuel and water in a multi-layered liquid column and A water-injection diesel engine, characterized in that the injected water in a cycle is controlled to completely complete the injection in the cycle.