JPH08226360A - Binary fluid injection device - Google Patents

Abstract

PURPOSE: To hold the ratio of the amount of fuel to the amount of inactive fluid at an appropriate value by setting the actual amount of fuel injected through the addition in advance to the requested amount of fuel injected of the amount of compensating fuel which is equivalent to the amount of inactive fluid such as water supplied in accordance with the operating condition of a diesel engine, time requested amount of fuel injected being suited to the operating condition. CONSTITUTION: An injection nozzle placed in an engine combustion chamber has a fuel reservoir 12 provided above a nozzle hole 11 provided at its end. A water reservoir 13 from which water is introduced into a fuel supply line 17 is formed above the fuel reservoir 12, one end of the water reservoir 13 serving as a junction 13a where the fuel joins with the water. Further, a water supply line 18 through which water passed through the water reservoir 13 and the junction 13a is supplied to the fuel supply line 17 is provided, and a valve element 15 which provides and shuts off communication between the nozzle hole 11 and the fuel reservoir 12 is enclosed in the injection nozzle 10. The operation of a pump is controlled in accordance with the actual amount of fuel injected which is set through the addition in advance to the requested amount of fuel injected of the amount of compensating fuel which is equivalent to the amount of water supplied in accordance with the operating condition.

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, and more particularly to a two-fluid injection device for simultaneously injecting fuel and water from a single nozzle.

[0002]

2. Description of the Related Art As one of means for reducing nitrogen oxide (NOx) in exhaust gas of a diesel engine, as shown in FIG. 7, a two-fluid injector for injecting fuel and water from the same fuel injection hole. Is proposed.

In FIG. 7, the two-fluid injection device is an injection nozzle provided with a fuel supply passage 61, a water supply passage 62, a check valve 63 provided in the water supply passage, a fuel reservoir 64, a valve body 65 and a water reservoir 66. 60, a fuel control rack for adjusting the fuel injection amount according to the operating state of the engine, a fuel injection pump 70 for supplying fuel to the injection nozzle at high pressure, and a water control rack for adjusting the water amount. , Water supply pump 8 for supplying water to the injection nozzle at high pressure
0 and control means 90 for controlling the operation of the water supply pump 80 by setting the amount of water according to the fuel injection amount.

The operation of this two-fluid ejecting apparatus will be described. The fuel injection pump 70 operates the fuel control rack according to the operating state of the engine to adjust the fuel injection amount and supplies the fuel to the injection nozzle 60 to inject it. At approximately the same time as this operation, the control means 90 detects the fuel injection amount from the position of the fuel control rack, sets the water amount corresponding to this fuel injection amount, and sets the water supply pump 80 at a timing different from the fuel injection timing. Activate. The water supply pump 80
The water control rack is operated according to the set water amount to adjust the water supply amount, and the water is supplied to the injection nozzle 60. The water supplied to the injection nozzle 60 flows into the fuel supply passage 61 through the check valve 63, the water supply passage 62 and the water reservoir 66. Next, when the fuel injection pump 70 is operated, water and fuel are simultaneously injected from the injection nozzle 60. Therefore, water is introduced into the combustion chamber to lower the temperature in the combustion chamber, and nitrogen oxides (NOx) are reduced.

[0005]

In the above-mentioned two-fluid injection device, the effect of reducing nitrogen oxides (NOx) in the exhaust gas is obtained substantially in proportion to the injection amount of water. However,
In the above-described two-fluid injection device, when water is supplied to the injection nozzle, the fuel in the fuel passage is returned to the fuel injection pump due to the inflow of water, so the required fuel injection amount according to the operating state of the engine On the other hand, the amount of fuel to be actually injected becomes small, combustion failure occurs, stable operation of the engine cannot be obtained, torque is reduced, and hydrocarbon (HC) increases. There is a point.

Therefore, the present invention has been made in view of the above-mentioned problems, and provides a two-fluid injection device which always maintains an optimal ratio of fuel and water and injects fuel and water simultaneously in this condition. The purpose is to provide.

[0007]

According to a first aspect of the present invention, there is provided an injection nozzle which is disposed so as to face a combustion chamber of an engine and which injects fuel and an inert fluid into the combustion chamber, and an inside of the injection nozzle. And a fuel reservoir communicating with the combustion chamber through the injection hole, and a valve element that is slidably accommodated inside the injection nozzle to open and close the injection hole and is urged to close the injection hole. , A first passage having one end communicating with the fuel reservoir, a water reservoir having one end communicating with the first passage, a second passage having one end communicating with the water reservoir, and a valve body for feeding fuel through the first passage at a fuel injection timing. The valve element is urged through the second passage and the water reservoir at a time different from the fuel supply means for supplying the fuel to the fuel reservoir at a pressure higher than the urging force being urged and the fuel injection timing. An inert fluid supply means for supplying to the first passage at a pressure lower than the urging force; And a valve means for permitting only inflow from the inert fluid supply means to the fuel reservoir, and a required fuel injection amount according to the operating state of the engine, and an inert fluid amount to be supplied according to the operating state. A control means for setting an actual fuel injection amount by adding a corresponding fuel correction amount in advance and controlling the operation of the fuel supply means based on this fuel injection amount.

According to a second aspect of the present invention, in the two-fluid injection device according to the first aspect, the control means sets the required inert fluid amount according to the operating state of the engine, and the inert fluid required amount is set based on the required inert fluid amount. It is characterized in that the operation of the active fluid supply means is controlled.

According to a third aspect of the present invention, in the two-fluid injection device according to the second aspect, the control means includes an engine load detecting means for detecting an engine load and an engine speed detecting means for detecting an engine speed. It is characterized in that the required amount of inert fluid is set in accordance with the detected values of the engine speed and engine load detected by the engine load detection means and the engine speed detection means.

According to a fourth aspect of the present invention, there is provided the two-fluid ejecting apparatus according to the first aspect, the second aspect, or the third aspect.
The fuel supply means connects the first passage and the fuel supply means to each other to regulate the pressures of the fuel and water to a predetermined value when the pressures of the fuel and water become higher than the predetermined value except at the fuel injection timing. This is a configuration having a pressure regulating valve.

[0011]

According to the first aspect of the present invention, the fuel correction amount corresponding to the amount of the inert fluid supplied according to this operating condition is previously set to the required fuel injection amount according to the operating condition of the engine by the control means. Since the actual fuel injection amount is set in addition, even if the inert fluid amount is supplied to the injection nozzle and the fuel is returned to the fuel supply means, the ratio between the fuel amount and the inert fluid amount becomes an appropriate ratio. To be kept.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows the overall structure of a two-fluid injection device for injecting two fluids, water as an inert fluid and fuel, in a diesel engine. The two-fluid injection device includes an injection nozzle 10 for injecting fuel and water from one nozzle, a fuel injection pump 20 as a fuel supply means for supplying fuel to the injection nozzle 10, and an inert gas for supplying water to the injection nozzle 10. It comprises a water supply pump 30 as a fluid supply means, and a control means 40 for controlling the operation of the fuel injection pump 20 and the water supply pump 30.

FIG. 2 shows an enlarged view of the tip of the injection nozzle 10. The injection nozzle 10 is arranged so as to face a combustion chamber of an engine (not shown), and an injection hole 11 for injecting fuel and water into the combustion chamber is provided at the tip of the injection nozzle 10. Injection nozzle 10
A fuel reservoir 12 that communicates with the injection hole 11 and stores fuel is formed above the injection hole 11 inside. In addition, fuel sump 1
A water reservoir 13 that guides water to a fuel supply path 17, which will be described later, is provided at the upper part of the water reservoir 2, and at one end of the water reservoir 13 is a confluence portion 13a where the fuel and water merge. Inside the injection nozzle 10, a valve body 15 biased at a rate of 180 kg / m ² by a spring 14 is slidably accommodated in a direction to close the communication between the injection hole 11 and the fuel reservoir 12. Further, inside the injection nozzle 10, a fuel supply passage 17 as a first passage for passing the merging portion 13a to supply fuel to the fuel reservoir 12, and a fuel supply passage for passing the water reservoir 13 and the merging portion 13a. Water supply passage 1 as a second passage for supplying water to 17
8 are provided. That is, the fuel supply path 17 and the water supply path 18 are connected at one end at the confluence portion 13a. The fuel supply passage 1 is connected to the water supply passage 18 through the water reservoir 13.
Check valve 1 as valve means for allowing only water flow to 7
9 (see FIG. 1). The valve means may be an electromagnetic opening / closing valve that opens in synchronization with the supply of water to the fuel supply passage 17.

As shown in FIG. 3, the fuel injection pump 20
Is an in-line pump that is driven by the rotational force of the engine, and has a plunger, a control rack, and the like, an injection pump main body 21 that pressurizes the fuel to a high pressure, a fuel tank 22 that stores the fuel, The fuel filter 23 for removing dust and water from the
A feed pump 24 for supplying fuel to the injection pump main body 21 via a fuel injection pre-stroke pump 25 for adjusting the fuel injection amount and the fuel injection timing, respectively.
And the pressure in the injection nozzle 10 is a predetermined pressure, for example 60 k
When it exceeds g / m ² , it is composed of a check pressure regulating valve 27 (CPV) that causes the fuel in the fuel supply passage 17 to flow back into the fuel injection pump 20 to release the pressure in the injection nozzle 10.

As shown in FIG. 4, the water supply pump 30 is
Similar to the fuel injection pump 20 except for the check pressure regulating valve 27, an injection pump main body 31, a water tank 32, a water filter 33, a feed pump 34, a water injection prestroke pump that pressurizes water to, for example, 100 kg / m ^2. And 35.

A pre-stroke pump is used as the fuel adjusting unit for adjusting the fuel injection amount and the fuel injection timing of the fuel injection pump 20, but the fuel injection amount is adjusted based on the signal from the control means 40. It may be composed of an electronically controlled fuel governor and a timer for adjusting the fuel injection timing by the rotation angle of the cam shaft driven by the rotational force of the engine. Similarly, the water adjustment unit that adjusts the water injection amount and the water injection timing of the water supply pump 30 may be composed of an electronic control governor for water and a timer for water.

In FIG. 1, the control means 40 comprises a fuel control unit 41 for calculating the amount of fuel and a water control unit 42 for calculating the amount of water. The fuel control unit 41 includes an engine rotation sensor 43 that detects an engine speed Ne, an accelerator pedal position detection sensor 44 that detects an engine load L,
The fuel injection pump 20 and the water control unit 42 described above are connected to each other. The water supply pump 30 is connected to the water control unit 42,
This unit 42 has a storage circuit that stores the water supply amount after the water supply is performed until the next engine speed Ne and the engine load L are received from the fuel control unit 41 until the next water supply. I have it. Fuel control unit 41 and water control unit 4
2 is in signal communication with each other, and engine speed N
Information such as e and engine load L is also transmitted to the water control unit 42.

Next, setting of the respective amounts of fuel and water is performed by the fuel injection amount calculation routine of the fuel control unit 41 shown in FIG. 5 and the water control unit 4 shown in FIG.
Each will be described in accordance with the water supply amount calculation routine of 2.
First, the fuel injection amount calculation routine will be described. At step a1, the engine speed Ne and the engine load L
Are read from the engine rotation sensor 43 and the accelerator pedal position detection sensor 44 to detect the engine operating state, and the process proceeds to step a2. In step a2, the required fuel injection amount according to the engine speed Ne and the engine load L is set using a fuel injection amount calculation map (not shown). Further, the required fuel injection amount corresponds to the fuel correction amount according to the engine speed Ne and the engine load L, that is, the required water supply amount set in the water supply calculation routine described later and stored in the storage circuit. The fuel injection amount to be supplied to the injection nozzle is set by adding the fuel correction amount.
In step a3, the fuel injection amount set in step a2 is output to the fuel injection pump 20, and the process returns to step a1.

When the engine is operating under a low load, water is not required to be supplied to the combustion chamber. In this state, the engine is operated using a fuel injection amount calculation map (not shown). The required fuel injection amount is set according to the state, and the fuel injection amount supplied to the injection nozzle is set.

Next, the water supply amount calculation routine will be described. At step b1, the engine speed Ne and the engine load L are passed through the fuel control unit 41.
Are read to detect the engine operating state, and the process proceeds to step b2. At step b2, the engine speed N
The required water injection amount corresponding to e and the engine load L is set using a water supply amount calculation map (not shown), and the required water injection amount is stored in the storage circuit. In step b3, the required water injection amount set in step b2 is output to the water supply pump 30, and the process returns to step b1.

The operation of injecting the fuel amount and the water supply amount set by the fuel injection amount calculation routine and the water supply amount calculation routine from the injection nozzle 10 will be described. First,
In the fuel injection pump 20, the fuel is supplied from the fuel tank 22 via the fuel filter 23 to the injection pump main body 21 by the feed pump 24. The supplied fuel is adjusted by the pre-stroke pump 25 to the fuel injection amount set in the fuel injection amount calculation routine and is pressurized, and is supplied to the fuel reservoir 12 via the check pressure regulating valve 27 and the fuel supply passage 17. Supplied. When the fuel is supplied to the fuel reservoir 12, the pressure of the fuel in the fuel reservoir 12 gradually rises, and this pressure becomes a predetermined pressure (the biasing force of the spring 14 is 180 kg / m 2.
^{When 2} ) is reached, the valve body 15 rises slightly against the biasing force of the spring 14. A gap is formed between the valve body 15 and the fuel reservoir 12, and the fuel is injected through the gap into the combustion chamber through the injection hole.

On the other hand, in the water supply pump 30, as in the fuel injection pump 20, water is supplied from the water tank 32 by the feed pump 34 through the water filter 33 to the water pump main body 3.
1 is supplied. The supplied water is adjusted to a pressure (100 kg / m ² ) lower than the urging force of the spring 14, and is adjusted to the water supply amount set by the water supply amount calculation routine.
After the completion of fuel injection, the fuel flows into the water supply passage 18 and the water reservoir 13 via the check valve 19. At this time, the water has a pressure (100 kg / m ² ) lower than the urging force of the spring 14 (180 kg / m ² ).
Since the pressure is regulated to m ² ), the valve body 15 is not raised. Further, the water leaves the fuel in the fuel reservoir 12 and pushes the fuel in the merging portion 13a and the fuel supply passage 17 back to the fuel injection pump 20 side, thereby increasing the pressure in the fuel supply passage 17. When this pressure exceeds 60 kg / m ² , the check pressure regulating valve 27 operates and the fuel in the fuel supply passage 17 is returned to the fuel injection pump 20. At this time, the amount of fuel returned to the fuel injection pump 20 and the amount of supplied water are substantially the same.

In practice, in the fuel injection amount calculation routine, the amount of water previously supplied to the fuel supply passage 17 (in other words, the amount of fuel returned to the fuel injection pump 20) is set to the required fuel injection amount corresponding to the engine operating state. Since it is added,
By supplying water to the fuel supply path 17 and returning the fuel to the fuel injection pump 20, an appropriate ratio between the fuel amount and the water amount is maintained.

Next, when the fuel injection pump 20 is operated to inject fuel, the fuel in the fuel reservoir 12 is first injected, and then the water flowing into the fuel supply passage 17 is injected,
Finally, the fuel from the fuel injection pump 20 is injected. At this time, the water in the water supply passage 18 and the water reservoir 13 is not returned to the water supply pump 30 by the operation of the check valve 19. As a result, the fuel in the combustion chamber is reliably ignited in the early stage of the combustion stroke, the temperature in the combustion chamber is suppressed by the subsequent water injection, and finally a predetermined amount of fuel is injected to burn the fuel in the combustion chamber and drive power appear.

[0025]

According to the invention of claim 1, the amount of fuel returned to the fuel supply means is added to the fuel supplied to the injection nozzle in advance, and the fuel is generated by the inert fluid supplied to the injection nozzle. Even if it is returned to the fuel supply means, the ratio of the amount of fuel to the amount of inert fluid is maintained at an appropriate ratio, so even if the inert fluid is injected into the combustion chamber, good combustion can be achieved without causing combustion failure. As a result, the engine operates stably and high torque is obtained. Further, since the inert fluid is injected at a proper ratio with respect to the fuel injection amount, nitrogen oxide (N
Ox) and hydrocarbons (HC) can be reduced.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of a two-fluid ejection device of the present invention.

FIG. 2 is an enlarged front view of the tip of the injection nozzle shown in FIG.

FIG. 3 is a configuration diagram of the fuel injection pump shown in FIG. 1.

FIG. 4 is a configuration diagram of the water supply pump shown in FIG. 1.

FIG. 5 is a flowchart of a fuel injection amount calculation routine.

FIG. 6 is a flowchart of a water supply amount calculation routine.

FIG. 7 is an overall configuration diagram of a conventional two-fluid ejecting device.

[Explanation of symbols]

10 injection nozzle 11 injection hole 12 fuel reservoir 13 water reservoir 15 valve body 17 fuel supply passage as first passage 18 water supply passage as second passage 19 check valve as valve means 20 fuel injection pump as fuel supply means 27 Check pressure control valve 30 Water supply pump 40 as water supply means 40 Control means 41 Fuel control unit 42 Water control unit 43 Engine rotation sensor as engine speed detection means 44 Accelerator pedal position detection sensor as engine load detection means

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yuji Oda 5-717-1, Fukahori-cho, Nagasaki-shi, Nagasaki ・ Mitsubishi Heavy Industries, Ltd.

Claims (4)

[Claims] 1. An injection nozzle which is disposed so as to face a combustion chamber of an engine and injects fuel and an inert fluid into the combustion chamber; and the combustion nozzle which is formed inside the injection nozzle and which is formed through an injection hole. A fuel reservoir communicating with the chamber, a valve body slidably accommodated inside the injection nozzle to open and close the injection hole, and urged to close the injection hole, and one end of the fuel reservoir. A first passage communicating with the first passage, a water reservoir having one end communicating with the first passage, a second passage having one end communicating with the water reservoir, and a valve body for feeding the fuel through the first passage at a fuel injection timing. The fuel supply means for supplying the fuel to the fuel reservoir at a pressure higher than the urging force being applied, and the inert fluid through the second passage and the water reservoir at a timing different from the fuel injection timing. When the pressure is lower than the biasing force of Inert fluid supply means for supplying to the passage, valve means provided in the second passage for allowing only inflow from the inert fluid supply means to the fuel reservoir, and required fuel depending on the operating state of the engine An actual fuel injection amount is set by previously adding a fuel correction amount corresponding to the amount of inert fluid supplied according to this operating state to the injection amount, and the operation of the fuel supply means is performed based on this fuel injection amount. A two-fluid ejecting apparatus comprising: 2. The control means sets a required amount of inert fluid in accordance with the operating state of the engine, and controls the operation of the inert fluid supply means based on the required amount of inert fluid. The two-fluid ejection device according to claim 1. 3. The control means comprises an engine load detecting means for detecting an engine load and an engine speed detecting means for detecting an engine speed. The engine load detecting means and the engine speed detecting means detect the engine load. The two-fluid injection device according to claim 2, wherein the required amount of inert fluid is set according to the detected values of the engine speed and the engine load that have been set. 4. The fuel supply means, when the pressure of fuel and water becomes higher than a predetermined value except at the fuel injection timing,
3. A check pressure regulating valve for regulating the pressures of fuel and water to the predetermined value by connecting the first passage and the fuel supply means to each other. Item 2. The two-fluid ejection device according to Item 3.