JP2000027713A - Fuel/water injection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent excessive fuel injection when water is not supplied by surely detecting the supply of water in a fuel/water injection device. SOLUTION: A check valve 21 is arranged on a water supply passage 5 inside a fuel/water injection nozzle main body 2 for allowing the flow to the side of a front chamber 10 alone. Operation of a valve element 22 of the check valve 21 is sensed by means of a gap sensor 24. An electronic controller 11 determines whether or not the water is normally supplied according to the operation state of the valve element 22. In such a case, excessive fuel injection is prevented when the water is not supplied. Possibility of excessive fuel injection is eliminated by surely sensing force-feeding of the water. Generation of black smoke and abrupt torque fluctuation are eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a fuel / water injection device for sequentially injecting fuel and water from the same injection nozzle.

[0002]

BACKGROUND ART For example, NO _X exhausted from diesel engines is highly dependent on the flame temperature during combustion in the combustion chamber. Therefore, conventionally, the fuel into the combustion chamber with fuel, water injection system injects water, is possible to reduce the emissions of the NO _X by suppressing the combustion temperature has been performed (JP-A-5-164003 Gazette).

A fuel / water injection device is provided with a fuel / water injection nozzle by providing a water passage in a fuel injection nozzle provided with a fuel passage. The fuel / water injection device includes a fuel injection pump for injecting fuel and water into a combustion chamber. A water injection pump that supplies the fuel into the fuel / water injection nozzle in a layered manner, and a check valve that prevents backflow to the water supply pump during injection is provided in the water passage of the fuel / water injection nozzle. I have.

[0004] The supply of water into the fuel / water injection nozzle by the above-described fuel / water injection device is performed by pumping a required amount from a water supply pump at a time when the residual pressure in the fuel injection pipe is stabilized. The pumping pressure at this time is set to be equal to or lower than the valve opening pressure of the injection nozzle so that the needle valve does not open. The pumped water pushes the check valve open and is sent to the fuel passage through the junction of the water passage and the fuel passage. The sent water pushes back the fuel on the fuel injection pump side from the junction, and the fuel and water are replaced by that much. The fuel located on the side of the front end chamber from the merging portion remains as it is without being replaced with water.

Thus, the initial fuel from the nozzle tip,
The supplied water and fuel are arranged in the injection nozzle in layers in the order of water and fuel. By pumping the fuel from the fuel injection pump at the fuel injection timing, the fuel is injected into the combustion chamber in the order of initial fuel, supplied water, and fuel. Therefore, water is injected together with the fuel into the combustion chamber, so that the combustion temperature can be suppressed and the NO _X amount can be reduced.

[0006]

In the conventional fuel / water injection device, one pump for injecting fuel and water into the combustion chamber is provided on the fuel injection pump side, and the total injection amount of fuel and water is injected. The fuel injection pump is instructed and driven. Therefore, if water is not supplied in the water injection area, the amount of water with respect to the total injection amount is replaced by fuel, and the required fuel amount is increased by the amount of fuel replaced with water. Is injected, and there is a possibility that black smoke is generated or a sudden torque fluctuation occurs.

On the other hand, in a fuel / water injection device, there is known a technique of detecting an operation of a spool valve for supplying water under pressure and judging whether or not water has been supplied in accordance with the operation of the spool valve. See JP-A-6-346812). However, in this case, since the pumping of water is indirectly detected by the operation of the spool valve, the spool valve may operate due to elastic deformation of water or air, which may cause erroneous detection. .

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a fuel / water injection device that reliably detects water pumping and does not inject excessive fuel.

[0009]

In order to achieve the above-mentioned object, the present invention is directed to a water supply passage inside a main body of a spray nozzle or a water supply passage between a spray nozzle and a water spray amount adjusting means. It is provided with operation detection means for detecting the operation of the check valve that allows only the flow to the tip end side of the nozzle, and determines whether or not water is normally supplied according to the operation state of the check valve detected by the operation detection means. Judgment is made by the water supply judgment function of the control means, and by detecting the operation of the check valve that operates directly with water, the presence or absence of water supply is reliably detected.If water is not supplied, excess fuel is Prevent injection.

[0010]

FIG. 1 shows the overall configuration of a fuel / water injection device according to an embodiment of the present invention, and FIG. 2 shows an enlarged view of a main part in FIG.

As shown in FIG. 1, a fuel passage 4 and a water supply passage 5 for water are provided inside a fuel / water injection nozzle main body 2 as an injection nozzle in the fuel / water injection device 1. The water supply passage 5 communicates with a water supply pump device 6 as a water injection amount adjusting means for adjusting the injection amount of water, and the fuel passage 4 has a fuel injection as a fuel injection amount adjusting means for adjusting the fuel injection amount. The pump device 7 is in communication. The fuel passage 4 and the water supply passage 5 communicate with each other at a lower junction 8, and the junction 8 is connected to a distal end chamber 10 provided with a needle valve 9 of a nozzle portion.

The operations of the water supply pump device 6 and the fuel injection pump device 7 are controlled in accordance with commands from an electronic control device 11 as control means. The electronic control unit 11 receives information from an operating state detecting unit 12 that detects operating states such as an accelerator pedal depression amount, an engine rotation speed, and a coolant temperature, and the operating state detected by the operating state detecting unit 12. The operation of the water supply pump device 6 and the fuel injection pump device 7 is controlled by a command from the electronic control device 11 in accordance with the above.

As shown in FIGS. 1 and 2, the water supply passage 5 is provided with a check valve 21 comprising a spring 23 and a valve body 22. The spring 23 urges the valve body 22 to supply water. The supply passage 5 is always kept closed. When water is pressure-fed from the water supply pump device 6 side, the valve body 22 opens against the urging force of the spring 23, and the flow of water to the junction 8 is allowed. A gap sensor 24 is provided in the vicinity of the valve body 22 as operation detecting means.
4, the operation of the valve body 22 (the operation of the check valve 21) is detected. The detection signal of the gap sensor 24 is transmitted to the electronic control unit 1
When the output of the gap sensor 24 has a periodicity (for example, a period twice as long as the engine speed), the valve body 22 operates normally and the water is supplied normally. (Water supply judgment function).

The fuel / water injection device 1 described above
The supply of water into the water injection nozzle main body 2 is controlled by the electronic control unit 11 according to the operation state detected by the operation state detection unit 12.
When the residual pressure in the fuel passage 4 is stabilized according to the above command, the required amount is pumped from the water supply pump device 6.
The pumping pressure at this time is set to be equal to or lower than the valve opening pressure of the injection nozzle so that the needle valve 9 does not open. The pumped water pushes open the valve body 22 of the check valve 21 and is sent to the fuel passage 4 via the junction 8. The sent water pushes back the fuel on the side of the fuel injection pump upstream of the junction 8, and the fuel and water are replaced by that much. The fuel in the fuel passage 4 on the side of the front end chamber downstream of the junction portion 8 remains in a state of being retained without being replaced by water.

Thus, in the fuel passage 4, the initial fuel, the supplied water, and the fuel from the tip chamber 10 provided with the needle valve 9 of the nozzle portion are arranged in a layered order. The needle valve 9 is opened by pumping the fuel from the fuel injection pump device 7 at the fuel injection timing, and the fuel is injected into the combustion chamber in the order of initial fuel, supplied water, and fuel. Accordingly, in the water with the fuel is injected into the combustion chamber, it is possible to reduce the NO _X emissions by suppressing the combustion temperature.

During the water injection described above, the operation of the valve element 22 of the check valve 21 is detected by the gap sensor 24, and the output of the gap sensor 24 is output to the electronic control unit 1.
1 is input. When the output of the gap sensor 24 has a periodicity, the electronic control unit 11 determines that the valve body 22 operates normally and water is normally supplied, and the output of the gap sensor 24 is irregular. If no output is obtained, it is determined that the water is not normally supplied because the valve body 22 does not operate normally.

The situation of the water supply judging function will be described with reference to FIGS. FIG. 3 is a flowchart showing the operation of the water supply determination function of the electronic control unit 11, and FIG. 4 shows the state of the output of the gap sensor 24.

As shown in FIG. 3, during the water injection, the output of the gap sensor 24 is read in step S1, and it is determined in step S2 whether the output of the gap sensor 24 has periodicity. Is done. For example, as shown in FIG. 4, it is determined whether or not the cycle of the output S of the gap sensor 24 is twice as long as the cycle of the engine rotation signal Ne (from compression top dead center to exhaust top dead center). .

If it is determined in step S2 that the output S of the gap sensor 24 is a periodic output, the valve 2
2 operates normally and the water is normally supplied, so the water injection permission flag is set in step S3. That is,
Injection to the combustion chamber is performed in the order of initial fuel, supplied water, and fuel in the fuel passage 4.

When it is determined in step S2 that the output S of the gap sensor 24 is not an output having periodicity, when it is determined that the valve body 22 is not operating normally and water is not normally supplied. In step S4, the water injection prohibition flag is set. That is, fuel injection in a state where water is not supplied into the fuel passage 4 is performed, and a normal fuel amount without water injection is supplied to the combustion chamber.

Therefore, in the fuel / water injection device 1, since the movement of the valve body 22 of the check valve 21 is detected and the state of the water is directly detected to determine whether or not water has been supplied. The presence / absence of supply can be detected without erroneous detection. For this reason, even when water is not supplied to the water supply passage 5 for some reason, excessive fuel injection is not performed by injecting a normal amount of fuel without water injection, so that black smoke is discharged and a sudden torque There is no risk of fluctuation.

In this embodiment, the check valve 2
Since there is no pipe connection on the downstream side of 1 and the water after passing through the check valve 21 does not leak outside, the water supply pump device 6 and the fuel / water injection nozzle main body 2 Is more reliable in detecting the presence or absence of water supply than when a check valve is arranged in the pipe.

In the embodiment described above, the gap sensor 24 is used as the operation detecting means.
If the operation of the valve body 22 can be detected,
It is also possible to apply a switch that is directly turned on / off by a switch, a sensor that detects the deflection of the spring 23, and the like. Further, the portion where the check valve 21 is provided may be a water supply passage between the fuel / water injection nozzle main body 2 and the water supply pump device 6, and a delivery valve having a check valve function of the water supply pump device 6 may be used. It may be applied as a check valve, and a means for detecting the operation of the delivery valve may be provided as the operation detecting means.

[0024]

According to the fuel / water injection device of the present invention, only the flow toward the tip of the injection nozzle is supplied to the water supply passage inside the main body of the injection nozzle or the water supply passage between the injection nozzle and the water injection amount adjusting means. An allowable check valve is provided, and operation detecting means for detecting operation of the check valve is provided, and control means for determining whether or not water is normally supplied based on an operation state of the check valve detected by the operation detecting means. By judging by the water supply judgment function and detecting the operation of the check valve that operates directly with water, the water supply state is judged, so the presence or absence of water supply can be reliably detected. In addition, it is possible to prevent excessive fuel from being injected when water is not supplied.
As a result, there is no possibility that the pumping of water is reliably detected and fuel is excessively injected, and it is possible to eliminate black smoke discharge and rapid torque fluctuation.

[Brief description of the drawings]

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

FIG. 2 is an enlarged view of a main part in FIG.

FIG. 3 is a flowchart of a water supply determination function.

FIG. 4 is a graph showing an output state of a gap sensor.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 fuel / water injection device 2 fuel / water injection nozzle main body 4 fuel passage 5 water supply passage 6 water supply pump device 7 fuel injection pump device 8 merging section 9 needle valve 10 tip chamber 11 electronic control device 12 operating state detecting means 21 reverse Stop valve 22 Valve element 23 Spring 24 Gap sensor

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F02M 25/02 A HF term (Reference) 3G066 AA07 AB02 AB08 AD12 BA24 BA25 BA28 BA31 CC06T CC14 CC66 CC69 CD26 CE13 DA01 DC03 DC04 DC09 DC14 3G092 AA02 AA06 AB03 AB17 BB01 DE06S DF03 DF10 DG05 EA02 EA14 EB05 EC01 FA04 FA17 FA18 HB00Z HB01X HB01Z HE01Z HE08Z HF08Z

Claims (1)

[Claims] An injection nozzle having a fuel supply passage and a water supply passage inside a main body and injecting fuel and water into a combustion chamber of an engine at one time of fuel injection, and communicating with the injection nozzle to control an injection amount of the fuel. Fuel injection amount adjusting means for adjusting, water injection amount adjusting means communicating with the injection nozzle to adjust the injection amount of water, operating state detecting means for detecting the operating state of the engine, and detection by the operating state detecting means A fuel / water injection device comprising: a fuel injection amount adjusting unit and a control unit that controls an operation of the water injection amount adjusting unit in accordance with the operated state. A check valve disposed in a water supply path between an injection nozzle and the water injection amount adjusting means and allowing only a flow toward the tip end of the injection nozzle; and an operation detecting means for detecting an operation of the check valve. The control means has a water supply determining function of determining whether or not water is normally supplied based on the operation state of the check valve detected by the operation detection means. Fuel and water injection device.