JP2003322063A - Dme fuel supply device of diesel engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a DME fuel supply device for a Diesel engine capable of supplying a DME fuel from a fuel tank to an oil sump chamber of an injection pump without using a driving means such as a feed pump. <P>SOLUTION: When a motor-driven compressor 23 is put ON and the gas phase part 4b in the fuel tank 4 is pressurized, the DME fuel of the liquid phase part 4a is sent out to a feed pipe 5, and the oil sump chamber 11, an injection pipe 3, a nozzle return pipe 7, and a refrigerant supply pipe 51 are filled with the DME fuel. The DME fuel supplied as refrigerant is gasified by a fuel carburetor 15 and sent out to a fuel cooler 6, and the DME fuel filling the oil sump chamber 11 is cooled by the vaporization heat. The DME fuel in the fuel tank 4 is supplied to the injection pump 1 by the relative pressure difference between the two generated by the temperature difference between the DME fuel in the oil sump chamber 11 cooled and the DME fuel in the fuel tank 4. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a diesel engine DME using DME (dimethyl ether) as a fuel.
The present invention relates to a fuel supply device.

[0002]

2. Description of the Related Art As a measure against air pollution by a diesel engine, attention has been paid to one using DME (dimethyl ether), whose exhaust gas is clean, as fuel instead of light oil. D
The ME fuel is a liquefied gas fuel, unlike the conventional fuel, light oil. That is, the boiling point temperature is lower than that of light oil, and light oil is a liquid at room temperature under atmospheric pressure.
ME has the property of becoming a gas at room temperature. For example, a DME fuel supply device for a diesel engine using DME as a fuel disclosed in Japanese Patent Laid-Open No. 11-107871 and the like pressurizes DME fuel in a fuel tank with a feed pump or the like and sends it to an injection pump.
The injection pump pressure-feeds the DME fuel in the oil reservoir supplied from the fuel tank to each fuel injection nozzle of the diesel engine by a predetermined amount at a predetermined timing.
Since the DME fuel pressurized by the feed pump is continuously supplied to the oil reservoir of the injection pump, the DME fuel overflows and is returned to the fuel tank so that the pressure of the DME fuel in the oil reservoir is kept constant. ing. That is, the DME fuel supplied from the fuel tank to the oil reservoir of the injection pump by the feed pump or the like is
It always circulates from the fuel tank through the oil reservoir and the overflow fuel pipe.

In such a fuel circulation type DME fuel supply device, since the DME fuel is constantly circulated, the temperature distribution in the oil sump chamber is likely to be uniform, thereby stabilizing the injection characteristics of each injection pump. There is an advantage. Further, even if the pressure of the feed pump is not controlled, the amount of DME fuel that overflows is controlled by an overflow valve or the like provided in the overflow fuel pipe, so that the pressure of DME fuel in the oil reservoir can be kept constant. Therefore, there is an advantage that the injection characteristics of each injection pump can be easily stabilized.

[0004]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
Since the fuel has a property of becoming a gas at room temperature as described above, it is vaporized when sucked by a suction pump. Therefore, a DME fuel feed pump needs to be pressurized and delivered by a mechanical pump such as a piston pump. Also,
Since DME fuel has a low viscosity, it is inefficient to pressurize and deliver it with a mechanical pump such as a piston type. Therefore, compared with the fuel supply system of diesel engine of light oil type,
A large-capacity pump is required, which may result in a large cost burden.

Further, since the DME fuel is constantly circulated, if the overflow fuel pipe is cracked, for example, the overflowed DME fuel will continue to leak, and a large amount of DME fuel may leak out. .

Further, when the DME fuel remaining in the oil return chamber and the nozzle return pipe of the fuel injection nozzle is recovered when the diesel engine is stopped, the DME fuel remaining in the overflow fuel pipe must also be recovered. However, it may take a long time to recover the DME fuel remaining in the DME fuel supply device after the diesel engine is stopped.

The present invention has been made in view of such a situation, and its problem is to supply the DME fuel from the fuel tank to the oil reservoir of the injection pump regardless of the driving means such as the feed pump. It is to provide a DME fuel supply device of a diesel engine capable of performing the above.

[0008]

In order to achieve the above object, the invention according to claim 1 of the present application provides DME fuel supplied from a fuel tank via a feed pipe by a predetermined amount at a predetermined timing. An injection pump for delivering to an injection pipe communicating with a fuel injection nozzle of a diesel engine, a nozzle return pipe for returning the DME fuel overflowing from the fuel injection nozzle to the feed pipe, and the DME fuel in the oil reservoir. An oil reservoir chamber fuel cooling device for cooling, an oil reservoir chamber fuel temperature detecting means for detecting a temperature of the DME fuel in the oil reservoir chamber, and a temperature of the DME fuel in the oil reservoir chamber for the oil reservoir chamber fuel cooling device. The DM in the fuel tank
E Fuel supply means for supplying the DME fuel in the fuel tank to the oil reservoir by a pressure difference between the oil reservoir and the fuel tank caused by adjusting the temperature to a temperature lower than the temperature of the E fuel. It is a DME fuel supply device for a diesel engine.

When the DME fuel in the oil sump chamber is cooled and the temperature of the DME fuel in the oil sump chamber decreases, the saturated vapor pressure of the DME fuel in the oil sump chamber decreases. Therefore, a differential pressure is generated between the saturated vapor pressure in the fuel tank and the saturated vapor pressure in the oil reservoir, which are substantially the same pressure at room temperature, and the pressure difference causes the DME fuel in the fuel tank to be pumped to the oil reservoir. It will be. Further, the DM in the oil reservoir is detected by the fuel temperature detecting means of the oil reservoir.
By detecting the temperature of the E fuel and controlling the temperature of the DME fuel in the oil storage chamber by the oil storage chamber fuel cooling device so that the pressure difference between the oil storage chamber and the fuel tank becomes substantially constant, The DME fuel in the fuel tank can be pumped to the oil reservoir at a constant pressure. Therefore, the hydraulic pressure of the DME fuel in the oil reservoir can be controlled to be substantially constant, whereby
The injection characteristic of each injection pump can be stabilized.

As a result, according to the DME fuel supply device for a diesel engine according to the first aspect of the present invention, the pressure difference between the saturated vapor pressure in the fuel tank and the saturated vapor pressure in the oil reservoir causes the fuel tank Since the DME fuel in the inside can be pressure-fed to the oil storage chamber at a substantially constant pressure, the DM from the fuel tank can be fed without relying on a driving means such as a feed pump.
The effect that the E fuel can be supplied to the oil reservoir is obtained.

According to a second aspect of the present invention, in the first aspect, the oil-cooling chamber fuel cooling device is configured to perform the D
It is configured to cool the ME fuel, and is provided with a fuel cooler that cools the DME fuel in the oil reservoir by utilizing heat of vaporization caused by vaporization of the DME fuel. It is a DME fuel supply device for a diesel engine.

As described above, since the DME fuel has a property of becoming a gas at room temperature, it constitutes a cooling cycle using the DME fuel as a refrigerant and utilizes the heat of vaporization due to the vaporization of the DME fuel. The DME fuel in the oil sump can be cooled. In other words, the fuel cooler that effectively utilizes the excellent characteristics of the DME fuel as a refrigerant is used to
Since the ME fuel is cooled, the oil storage chamber fuel cooling device can be rationally configured.

As a result, according to the DME fuel supply device for a diesel engine of the present invention as defined in claim 2, in addition to the function and effect of the invention as defined in claim 1, it is excellent as a refrigerant for DME fuel. The fuel cooler that effectively uses the characteristics can reasonably configure the fuel cooling device for the oil sump chamber.
The effect that the cost of the E fuel supply device can be reduced can be obtained.

According to a third aspect of the present invention, in the second aspect, the oil cooling chamber fuel cooling device includes a refrigerant supply pipe for supplying the DME fuel from the feed pipe, and the DME flowing in the refrigerant supply pipe. It is provided with a fuel vaporizer that vaporizes fuel and sends it to the fuel cooler, and a refrigerant supply pipe opening / closing solenoid valve that opens / closes the refrigerant supply pipe, and is controlled by controlling the opening / closing of the refrigerant supply pipe opening / closing solenoid valve. The DME fuel supply device for a diesel engine is characterized in that it has a structure.

Thus, by controlling the opening / closing of the refrigerant supply pipe opening / closing solenoid valve, the amount of vaporized DME fuel delivered to the fuel cooler can be controlled. Thereby, the fuel cooler can be controlled, so that the temperature of the DME fuel in the oil sump chamber can be controlled by the oil sump chamber fuel cooling device.

Thus, according to the DME fuel supply device for a diesel engine according to the third aspect of the present invention, the fuel cooler can be controlled by controlling the opening / closing of the refrigerant supply pipe opening / closing solenoid valve. According to the fuel cooling device for the oil sump chamber, the function and effect according to the invention described in claim 2 of the present application can be obtained.

According to a fourth aspect of the present invention, in the third aspect, the DME fuel mixed in the lubricating oil in the cam chamber, which is a dedicated lubricating system separated from the lubricating system of the diesel engine, is separated. An oil separator and an electric compressor that pressurizes the DME fuel separated by the oil separator and sends the pressurized fuel to the fuel tank are provided, and the DME fuel supplied from the refrigerant supply pipe to the oil reservoir fuel cooling device is A DME fuel supply device for a diesel engine, characterized in that the electric compressor delivers the fuel to the fuel tank.

As described above, since the DME fuel has a property of becoming a gas at room temperature, in order to supply the liquid DME fuel to the injection pump, the supply pressure to the injection pump is higher than that to the light oil fuel. There is a need to. Therefore, due to the high supply pressure to the injection pump, the amount of fuel that leaks into the cam chamber of the injection pump from the gap between the plunger barrel and the plunger of the injection pump that delivers DME fuel to the fuel injection nozzle of the diesel engine is light oil. There is a problem that the amount of fuel used will be greater than when fuel is used. Further, since DME has a lower viscosity than light oil, it easily leaks from the gap, and the amount thereof increases. Then, the DME fuel leaking from the gap between the plunger barrel and the plunger may flow into the cam chamber of the injection pump and vaporize, and the vaporized DME fuel may enter the crank chamber of the diesel engine and catch fire.

Therefore, the cam chamber is made to be a dedicated lubricating system separated from the lubricating system of the diesel engine, the DME fuel mixed in the lubricating oil in the cam chamber is separated by the oil separator, and the separated DME fuel is pressurized by the electric compressor. By sending the fuel to the fuel tank, it is possible to reduce the risk of causing such a problem. Then, by using this electric compressor to send the DME fuel supplied from the refrigerant supply pipe to the oil reservoir fuel cooling device to the fuel tank, without providing a dedicated refrigerant recovery means,
It is possible to recover the DME fuel supplied to the oil reservoir fuel cooling device as a refrigerant.

As a result, according to the DME fuel supply device for a diesel engine of the invention described in claim 4 of the present application, in addition to the function and effect of the invention of claim 2 or 3, a dedicated refrigerant recovery means is provided. Since the DME fuel supplied to the oil sump chamber fuel cooling device as the refrigerant can be recovered without providing it, the oil sump chamber fuel cooling device can be constructed at a lower cost.

The invention according to claim 5 of the present application is the DME fuel supply device for a diesel engine according to claim 4, further comprising a fuel tank temperature adjusting means for adjusting the temperature in the fuel tank. Is.

According to the DME fuel supply device for a diesel engine according to the invention described in claim 5 of the present application, in addition to the effect of the invention described in claim 4 of the present invention, in the fuel tank for adjusting the temperature in the fuel tank By the temperature control means,
Since the temperature of the DME fuel in the oil storage chamber can be controlled to the optimum temperature while maintaining the relative temperature difference between the oil storage chamber and the fuel tank, the optimum injection characteristic of the DME fuel can be obtained. The effect of being able to do is obtained.

According to a sixth aspect of the present invention, in the fifth aspect of the present invention, the fuel tank temperature adjusting means is provided after the DME fuel sent from the electric compressor is cooled through an air-cooling cooler. A first return path that is sent to a fuel tank, and a second return path that the DME fuel sent from the electric compressor is sent to the fuel tank without passing through the air-cooling cooler;
Controlling a return path switching electromagnetic valve for switching between the first return path and the second return path, a fuel tank internal temperature detecting means for detecting a temperature in the fuel tank, and the return path switching electromagnetic valve. And a fuel tank temperature controller for adjusting the temperature in the fuel tank according to the present invention.

According to the DME fuel supply device for a diesel engine of the present invention as defined in claim 6, the DME fuel delivered from the electric compressor is cooled and then delivered to the fuel tank. The temperature in the fuel tank can be controlled by controlling the return path switching solenoid valve that switches between the second return path in which the DME fuel sent from the electric compressor is not cooled and is sent to the fuel tank. Thereby, the function and effect of the invention described in claim 5 of the present application can be obtained.

The invention described in claim 7 of the present application includes
In any one of 6 above, a residual fuel recovery means capable of recovering the DME fuel remaining in the oil reservoir chamber of the injection pump and the nozzle return pipe into the fuel tank after the diesel engine is stopped. D of diesel engine characterized by having
It is an ME fuel supply device.

D in the injection system after the diesel engine is stopped
When the ME fuel remains, it leaks from the nozzle seat portion of the fuel injection nozzle into the cylinder of the diesel engine and is vaporized, and the cylinder is filled with the vaporized DME fuel. As a result, abnormal combustion such as knocking may occur when the diesel engine is started, and the diesel engine may not be normally started, which may cause large vibration and noise.
Therefore, when the diesel engine is started by recovering the DME fuel remaining in the oil sump chamber of the injection pump and the nozzle return pipe into the fuel tank after the diesel engine is stopped by the residual fuel recovery means. It is possible to reduce the risk of abnormal combustion such as knocking that occurs in the engine.

As a result, according to the DME fuel supply system for a diesel engine of the invention described in claim 7 of the present application, in addition to the function and effect of the invention described in any one of claims 1 to 6, the diesel engine is provided. It is possible to reduce the risk of abnormal combustion such as knocking when starting the engine.

According to an eighth aspect of the present invention, in the seventh aspect, the residual fuel recovery means includes an inlet side of the oil reservoir communicating with the feed pipe and a communication path of the nozzle return pipe. A DME remaining in the oil sump chamber of the injection pump and in the nozzle return pipe, comprising a communication path switching means for switching from the feed pipe to a residual fuel recovery pipe communicating with the inlet side of the electric compressor. Fuel is a DME fuel supply device for a diesel engine, characterized in that fuel is collected in the fuel tank by the electric compressor.

As described above, when the DME fuel remaining in the oil sump chamber and the nozzle return pipe is recovered when the diesel engine is stopped, the communication path between the oil sump chamber and the nozzle return pipe communicating with the feed pipe. Is switched to the residual fuel recovery pipe communicating with the inlet side of the electric compressor, and the electric compressor is driven, whereby the DME fuel remaining in the oil reservoir and the nozzle return pipe can be recovered.

As a result, according to the DME fuel supply device for a diesel engine of the present invention, the inlet side of the oil reservoir communicating with the feed pipe and the communication path of the nozzle return pipe are By the communication path switching means for switching from the feed pipe to the residual fuel recovery pipe communicating with the inlet side of the electric compressor,
It is possible to obtain the action and effect according to the invention described in claim 7 of the present application.

According to a ninth aspect of the present invention, in the eighth aspect, the communication between the liquid phase portion of the fuel tank and the feed pipe is cut off, and the gas phase portion of the fuel tank communicates with the feed pipe. A DME fuel supply device for a diesel engine, characterized by comprising a gas-phase fuel delivery means for delivering the gaseous DME fuel.

Since the gas phase portion of the fuel tank is filled with the DME fuel which is a gas having a pressure higher than that of the oil reservoir, the communication between the liquid phase portion of the fuel tank and the feed pipe is cut off when the diesel engine is stopped. When the gas phase part of the tank and the feed pipe are in communication, part of the fuel remaining in the feed pipe due to the pressure of the gas phase part of the fuel tank is pushed out toward the electric compressor through the refrigerant supply pipe. You can Therefore, the DM remaining in the oil sump chamber and the nozzle return pipe by the residual fuel recovery means.
Before the E fuel is collected, a part of the DME fuel remaining in the feed pipe in advance can be collected in the fuel tank by the gas-phase fuel delivery means by the electric compressor, so that the DME vaporized in the feed pipe can be collected.
Since the fuel is filled, the recovery time of the DME fuel by the residual fuel recovery means can be shortened.

As a result, according to the DME fuel supply device for a diesel engine of the invention described in claim 9 of the present application, in addition to the effect of the invention described in claim 8 of the application, the DME fuel of the residual fuel recovery means The effect that the collection time can be shortened is obtained.

The invention described in claim 10 of the present application is the invention of claim 1.
The sub fuel tank having a smaller capacity than that of the fuel tank is provided between the fuel tank and the feed pipe, and the fuel tank and the sub fuel tank are provided when the diesel engine is started. The sub fuel tank in which the gas phase portion is pressurized by the electric compressor by blocking the communication with the fuel tank and connecting the gas phase portion of the sub fuel tank with the outlet side of the electric compressor. From the DM
The DME fuel supply device for a diesel engine is characterized in that E fuel is supplied to the oil reservoir.

When starting the diesel engine, first,
DME fuel must be supplied to the oil reservoir of the injection pump, but initially there is no DME fuel in the oil reservoir, so the DME fuel in the fuel tank can be used by utilizing the hydraulic pressure difference between the oil reservoir and the fuel tank. It cannot be sent to the oil sump chamber. Therefore, by driving the electric compressor, the gas phase portion in the fuel tank is pressurized and the pressure of the liquid phase portion in the fuel tank is increased. Then, the DME fuel in the fuel tank pressurized by the electric compressor is delivered to the feed pipe by the pressure, and the DME fuel is filled in the oil reservoir.

However, it takes a certain amount of time to pressurize the inside of the fuel tank having a large capacity with the electric compressor, so the DME to the oil reservoir at the time of starting the diesel engine is required.
It may take a long time to fill the fuel. Therefore, a sub fuel tank having a smaller capacity than the fuel tank is provided between the fuel tank and the feed pipe. And D to the oil reservoir when starting the diesel engine
During the ME fuel filling operation, the communication between the fuel tank and the sub fuel tank is cut off, and the gas phase portion of the sub fuel tank and the outlet side of the electric compressor are made to communicate with each other. The DME fuel is supplied to the oil reservoir from the pressurized sub fuel tank. Since the sub fuel tank has a smaller capacity than the fuel tank, the pressurization time by the electric compressor can be shortened, so that the time for charging the DME fuel into the oil reservoir by the pressure of the electric compressor can be shortened.

As a result, according to the DME fuel supply device for a diesel engine of the invention described in claim 10 of the present application, in addition to the effect of the invention described in any one of claims 1 to 9, D at engine start
When the ME fuel is filled in the oil reservoir, the electric compressor compresses the sub fuel tank having a smaller capacity than the fuel tank provided between the fuel tank and the feed pipe, and the DME in the sub fuel tank is pressurized. Since the fuel is filled in the oil reservoir, it is possible to obtain the effect that the time for filling the DME fuel in the oil reservoir can be shortened.

The invention described in claim 11 of the present application is the same as claim 1.
In any one of 10 to 10, the DME fuel delivered from the injection pump is supplied to a common rail and is delivered to each fuel injection nozzle from the common rail. It is a DME fuel supply device for an engine.

According to the DME fuel supply apparatus for a diesel engine according to the invention of claim 11 of the present application, the DME fuel supply apparatus for a common rail type diesel engine is described in any one of claims 1 to 10 of the application. The effect of the invention can be obtained.

[0040]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. First, a first embodiment of a DME fuel supply device for a diesel engine according to the present invention will be described. FIG. 1 is a schematic configuration diagram showing a first embodiment of a DME fuel supply device according to the present invention.

A DME fuel supply apparatus 100 according to the present invention for supplying DME fuel to a diesel engine comprises an injection pump 1. The DME fuel in the liquid phase portion 4a of the fuel tank 4 is filtered from the liquid phase fuel outlet 41 by the filter 5a, and then supplied to the oil reservoir chamber 11 of the injection pump 1 via the feed pipe 5 and the three-way solenoid valve 21. It The three-way solenoid valve 21, which is a component of the “remaining fuel recovery means” described later, is in the ON state during the injection state (during operation of the diesel engine), and the feed pipe 5 communicates with the oil sump chamber 11. Injection pump 1
Has as many injection pump elements 2 as there are cylinders in the diesel engine.
An injection pipe 3 is connected to the fuel outlet of the injection pump element 2, the injection pipe 3 is connected to a fuel injection nozzle 9, and the high pressure compressed DME fuel delivered from the injection pump 1 is injected. It is pressure-fed to the fuel injection nozzle 9 through the pipe 3. Fuel injection nozzle 9
The DME fuel that has overflowed from is returned to the feed pipe 5 via the nozzle return pipe 7 and is again supplied to the oil reservoir 11.

Outside the oil sump chamber 11, DM of the oil sump chamber 11 is provided.
An “oil reservoir fuel cooling device” for cooling the E fuel is provided. The DME fuel is supplied as a refrigerant from the fuel tank 4 to the “oil reservoir fuel cooling device” via the refrigerant supply pipe 51 branched from the feed pipe 5. The DME fuel supplied as the refrigerant is supplied to the fuel vaporizer 15 via the refrigerant supply pipe opening / closing solenoid valve 16. And
The DME fuel vaporized by the fuel vaporizer 15 is supplied to the fuel cooler 6 using the heat of vaporization, and the heat of vaporization cools the DME fuel in the oil reservoir 11. The “oil reservoir fuel cooling device” is controlled by opening / closing the refrigerant supply pipe opening / closing solenoid valve 16.

The cam chamber 12 is a dedicated lubricating system separated from the lubricating system of the diesel engine, and the oil separator 13 is the cam chamber 1 in which the DME fuel leaking from the injection pump element 2 into the cam chamber 12 is mixed.
The lubricating oil in 2 is separated into DME fuel and lubricating oil, and the lubricating oil is returned to the cam chamber 12. The DME fuel separated by the oil separator 13 is sent to the electric compressor 23 through the check valve 14 that prevents the pressure in the cam chamber 12 from becoming lower than the atmospheric pressure, and after being pressurized by the electric compressor 23. , Is returned to the fuel tank 4. The DME fuel supplied as a refrigerant to the fuel cooler 6 of the “oil reservoir fuel cooling device” is also pressurized by the electric compressor 23 and then returned to the fuel tank 4.

As described above, the electric compressor 23 for recovering the DME fuel separated by the oil separator 13 is used to feed the DME fuel supplied from the refrigerant supply pipe 51 to the "oil reservoir fuel cooling device". By sending it to the tank 4, the DME fuel supplied to the "oil reservoir fuel cooling device" as a refrigerant can be recovered without providing a dedicated refrigerant recovery means.

D pressurized by the electric compressor 23
When the three-way solenoid valve 22 is off, the ME fuel is cooled by the cooler 41 as an “air-cooling cooler” and then returned to the fuel tank 4 (first return path). When the 3-way solenoid valve 22 is ON,
It is returned to the fuel tank 4 without passing through the cooler 41, that is, without being cooled (second return path). Therefore, the temperature of the DME fuel returned to the fuel tank 4 can be adjusted by the ON / OFF control of the three-way solenoid valve 22, and thus the temperature of the DME fuel in the fuel tank 4 can be controlled. The check valve 43 is for preventing the DME fuel from flowing back to the cooler 41 from the second return path.

Next, regarding the operation of the DME fuel supply system 100 shown in the embodiment, the diesel engine is stopped, the DME fuel is filled, the diesel engine is operated, and the residual fuel is recovered after the diesel engine is stopped. I will explain later.

FIG. 2 is a schematic configuration diagram showing a first embodiment of the DME fuel supply device 100 according to the present invention, showing a state when the diesel engine is stopped.

When the diesel engine is stopped,
The three-way solenoid valve 21, the three-way solenoid valve 22, and the refrigerant supply pipe opening / closing solenoid valve 16 are all off. The three-way electromagnetic valve 21 and the three-way electromagnetic valve 22 communicate with each other in the illustrated communication direction in the OFF state. The refrigerant supply pipe opening / closing solenoid valve 16 is a solenoid valve that communicates in the OFF state.

FIG. 3 is a schematic configuration diagram showing a first embodiment of the DME fuel supply device 100 according to the present invention, in which DM
It shows a state of being filled with E fuel.

In order to operate the diesel engine from the stopped state, the DME fuel in the fuel tank 4 is filled with the oil reservoir chamber 11 of the injection pump 1, the injection pipe 3, the nozzle return pipe 7, and the refrigerant supply pipe 51.
To fill. First, the three-way solenoid valve 21 and the three-way solenoid valve 22
Is turned on, and a communication path in the illustrated direction is formed. Subsequently, the electric compressor 23 is turned on, the return pipe 8 is sucked in the direction indicated by the symbol A, and the second return path communicated by the three-way solenoid valve 22 in the ON state is indicated by the symbol B. The gas phase portion 4b in the fuel tank 4 is pressurized and pressurized. Fuel tank 4
By pressurizing the gas phase portion 4b in the liquid phase portion 4a
Is sent to the feed pipe 5 (reference numeral C), and the oil reservoir 11, the injection pipe 3, the nozzle return pipe 7, and the refrigerant supply pipe 51 are filled with the DME fuel in the direction indicated by reference numeral D. Further, the DME fuel supplied as the refrigerant from the refrigerant supply pipe 51 is vaporized by the fuel vaporizer 15 and sent to the fuel cooler 6 of the “oil reservoir fuel cooling device”, and the heat of vaporization thereof causes the interior of the oil reservoir 11 to evaporate. The DME fuel filled in is cooled.

FIG. 4 is a schematic configuration diagram showing a first embodiment of the DME fuel supply device 100 according to the present invention, showing a state when the diesel engine is in operation.

At the time when each part is filled with DME fuel, the DME fuel in the fuel tank 4 becomes "oil reservoir fuel cooling device".
By the relative pressure difference between the DME fuel in the oil reservoir 11 and the DME fuel cooled in the fuel tank 4 and the DME fuel in the fuel tank 4 caused by the temperature difference between them, the pressure is fed to the feed pipe 5 (reference numeral E). That is, the DME fuel supply device 100 according to the invention of the present application does not include a pump for delivering the DME fuel from the fuel tank 4 to the injection pump 1, and the oil generated by cooling the DME fuel in the oil sump chamber 11 is generated. Due to the pressure difference between the reservoir chamber 11 and the fuel tank 4, the DME fuel in the fuel tank 4 is supplied to the injection pump 1 (fuel supply means).

Therefore, the oil reservoir chamber 11 is not provided with an overflow path, and the DME fuel pressure-fed (reference symbol F) from the oil reservoir chamber 11 to the fuel injection nozzle 9 by the injection pump element 2 through the injection pipe 3. Will be supplied only for that amount. Further, the DME fuel overflowing from the fuel injection nozzle 9 is returned to the feed pipe 5 via the nozzle return pipe 7 without being returned to the fuel tank 4 as in the conventional case.
It is again supplied to the oil sump chamber 11. As described above, the fuel cooler 6 effectively utilizing the excellent characteristics of the DME fuel as the refrigerant.
Since the "oil reservoir fuel cooling device" can be reasonably configured by the above, a driving means such as a feed pump becomes unnecessary, and the DME fuel supply device 10 for a diesel engine is provided.
The cost of 0 can be reduced.

In the oil sump chamber 11, a temperature sensor (oil sump chamber fuel temperature detection means) (not shown) is arranged. The cooling temperature of the oil sump chamber 11 is determined by the refrigerant supply pipe opening / closing solenoid valve 16
By controlling the opening and closing, the cooling temperature is controlled to a constant cooling temperature. That is, the temperature of the DME fuel in the oil storage chamber 11 detected by the temperature sensor arranged in the oil storage chamber 11 is
Solenoid valve for opening and closing the refrigerant supply pipe when the temperature falls below a predetermined temperature 1
6 is closed (ON), and when the temperature exceeds a predetermined temperature, the refrigerant supply pipe opening / closing solenoid valve 16 is opened (OFF) to keep the temperature of the DME fuel in the oil reservoir 11 constant. Thereby, D of the injection pump 1
The injection characteristic of ME fuel can be stabilized.

Further, a temperature sensor (fuel tank internal temperature detecting means) (not shown) is provided in the fuel tank 4, and the temperature of the DME fuel in the oil sump chamber 11 and the internal temperature of the fuel tank 4 are reduced. The three-way solenoid valve 22 (return path switching solenoid) is set so that the temperature difference from the temperature of the DME fuel becomes a constant temperature difference, that is, the pressure difference between the oil reservoir chamber 11 and the fuel tank 4 becomes constant. ON / OFF control of valve) and fuel tank 4
The temperature of the DME fuel inside is adjusted (fuel tank temperature adjusting means). As a result, the delivery pressure of the DME fuel delivered from the fuel tank 4 to the feed pipe 5 can be made constant (fuel tank temperature adjusting means). Therefore, the temperature of the DME fuel in the oil reservoir chamber 11 can be controlled to an optimum temperature while maintaining the relative temperature difference between the oil reservoir chamber 11 and the fuel tank 4, and thus the optimum temperature can be achieved. The injection characteristic of DME fuel can be obtained.

FIG. 5 is a schematic configuration diagram showing a first embodiment of the DME fuel supply device 100 according to the present invention, showing a residual fuel recovery operation after the diesel engine is stopped.

After the diesel engine is stopped, in order to prevent abnormal combustion such as knocking that occurs when the diesel engine is restarted due to filling of the cylinder with the vaporized DME fuel, the oil sump chamber 11, the injection pipe 3, The DME fuel filled in the nozzle return pipe 7 and the refrigerant supply pipe 51 is collected in the fuel tank 4 by the “residual fuel collecting means”. The “residual fuel recovery means” is composed of a three-way solenoid valve 21 (communication path switching means) and an electric compressor 23. When the three-way solenoid valve 21 is turned off after the diesel engine is stopped, the electric compressor 23 causes the DME fuel filled in the oil sump chamber 11, the injection pipe 3, the nozzle return pipe 7, and the refrigerant supply pipe 51 to have a code J. The fuel is collected in the fuel tank 4 through the route indicated by. When the three-way solenoid valve 22 is turned off, the DME fuel collected is
After being cooled by the cooler 42 in the first return path (path indicated by the symbol H), it is recovered in the fuel tank 4. In this way, the DME fuel can be supplied from the fuel tank to the oil reservoir without using a drive means such as a feed pump.

As the second embodiment, in addition to the first embodiment described above, there is one in which the vapor phase portion 4b of the fuel tank 4 and the feed pipe 5 can be connected. Figure 6
FIG. 3 is a schematic configuration diagram showing a second embodiment of the DME fuel supply device 100 according to the present invention.

The gas phase portion 4b of the fuel tank 4 is connected to the feed pipe 5 from the gas phase fuel outlet 44 via the gas phase fuel output pipe 311 and the three-way solenoid valve 31.
In the DME fuel supply device 100, the three-way solenoid valve 31 is OFF
In the case of the state, the oil reservoir 11 and the liquid phase portion 4 of the fuel tank 4
When the three-way solenoid valve 31 is in the ON state in communication with a,
The oil reservoir chamber 11 and the gas phase portion 4b of the fuel tank 4 communicate with each other. In the present embodiment, after the diesel engine is stopped, the oil remaining chamber 11, the injection pipe 3, the nozzle return pipe 7, and the refrigerant supply pipe 51 are filled with D by the “residual fuel recovery means”.
Before the ME fuel is collected in the fuel tank 4, the three-way solenoid valve 3
1 in the ON state, the high-pressure gaseous DM in the gas phase portion 4b
E Fuel is delivered to the feed pipe 5 (gas phase fuel delivery means).

FIG. 7 is a schematic configuration diagram showing a second embodiment of the DME fuel supply device 100 according to the present invention. The gas phase part 4b is fed to the feed pipe 5 before the residual fuel recovery operation after the diesel engine is stopped. It shows a state in which the two are communicated with each other.

Since the gas phase portion 4b of the fuel tank 4 is filled with high-pressure gas DME fuel, the three-way electrification valve 31 is turned on when the diesel engine is stopped, and the liquid phase portion 4a of the fuel tank 4 is turned on. Cut off the communication with the feed pipe 5,
When the vapor phase portion 4b of the fuel tank 4 and the feed pipe 5 are communicated with each other, the gaseous DME fuel in the vapor phase portion 4b is denoted by a symbol K.
It is sent through the route shown in. Then, the DME fuel in the feed pipe 5 on the oil reservoir 11 side of the three-way solenoid valve 31 and the DME fuel filled in the refrigerant supply pipe 51 are
The electric compressor 23 collects the fuel in the fuel tank 4 through the fuel cooler 6 along the path indicated by the symbol L.

As described above, before the DME fuel remaining in the oil reservoir 11 and the nozzle return pipe 7 is recovered by the "residual fuel recovery means", the feed pipe 5 and Part of the DME fuel remaining in the refrigerant supply pipe 51 can be recovered in the fuel tank 4 by the electric compressor 23, so that the feed pipe 5 and the refrigerant supply pipe 51 are filled with the vaporized DME fuel. It is possible to shorten the DME fuel recovery time by the "residual fuel recovery means".

Further, as a third embodiment, in addition to the second embodiment, a sub fuel tank having a smaller capacity than the fuel tank 4 is provided between the fuel tank 4 and the feed pipe 5. FIG. 8 is a schematic configuration diagram showing a third embodiment of the DME fuel supply device 100 according to the present invention.

Between the fuel tank 4 and the feed pipe 5, a sub fuel tank 45 having a smaller capacity than the fuel tank 4 is provided.
Is provided. In this embodiment, the capacity of the sub fuel tank 45 is about 1/100 of that of the fuel tank 4. The DME fuel supply device 100 shown in the embodiment is a fuel tank when filling the oil reservoir chamber 11, the injection pipe 3, the nozzle return pipe 7, and the refrigerant supply pipe 51 with DME fuel at the time of starting the diesel engine. Sub fuel tank 45 instead of 4
To supply DME fuel.

Next, regarding the operation of the DME fuel supply device 100 shown in the embodiment, the diesel engine is stopped, the DME fuel is filled, the diesel engine is operated, and the residual fuel is recovered after the diesel engine is stopped. I will explain later. The description of the same parts as those of the first and second embodiments will be partially omitted.

FIG. 9 is a schematic configuration diagram showing a third embodiment of the DME fuel supply device 100 according to the present invention, showing a state when the diesel engine is stopped.

When the diesel engine is stopped,
The three-way solenoid valve 21, the three-way solenoid valve 22, and the refrigerant supply pipe opening / closing solenoid valve 16 are all off. Further, the three-way solenoid valve 33 and the solenoid valve 32 that opens and closes the communication between the fuel tank 4 and the sub fuel tank 45 are also OFF. In the OFF state, the three-way solenoid valve 33 communicates with the fuel tank 4 side, and in the OFF state of the solenoid valve 32, the fuel tank 4 and the sub fuel tank 45 communicate with each other.

FIG. 10 is a schematic block diagram showing a third embodiment of the DME fuel supply device 100 according to the present invention.
It shows a state of being filled with ME fuel.

In order to operate the diesel engine from the stopped state, the DME fuel in the fuel tank 4 is charged with the oil reservoir chamber 11 of the injection pump 1, the injection pipe 3, the nozzle return pipe 7, and the refrigerant supply pipe 51.
To fill. First, the three-way solenoid valve 21 and the three-way solenoid valve 22
Are turned on to form communication paths in the illustrated directions. Further, the three-way solenoid valve 33 and the solenoid valve 32 are also turned on, the communication between the fuel tank 4 and the sub fuel tank 45 is cut off, and the communication path from the three-way solenoid valve 22 communicates with the sub fuel tank 45. Subsequently, the electric compressor 23 is turned on, the return pipe 8 is sucked in the direction indicated by the symbol A, and the gas phase of the sub fuel tank 45 communicated by the three-way solenoid valve 22 and the three-way solenoid valve 33 in the on state. The part is pressurized in the direction indicated by the symbol M, and the gas phase part in the sub fuel tank 45 is pressurized. By pressurizing the gas phase portion in the fuel tank 45, the DME fuel in the sub fuel tank 45 is delivered to the feed pipe 5 (reference numeral N),
The oil reservoir chamber 11, the injection pipe 3, the nozzle return pipe 7, and the refrigerant supply pipe 51 are filled with the DME fuel in the direction indicated by the symbol N.

FIG. 11 is a schematic block diagram showing a third embodiment of the DME fuel supply device 100 according to the present invention, showing a state when the diesel engine is in operation.

When each part was filled with DME fuel, 3
One-way solenoid valve 22, three-way solenoid valve 33 and solenoid valve 32 are ON
The state changes to the OFF state. Therefore, the return pipe 8 is connected to the cooler 42 via the electric compressor 23.
The DME fuel in the fuel tank 4 communicates with the DME in the oil reservoir 11 cooled by the “oil reservoir fuel cooling device”.
The fuel and the DME fuel in the fuel tank 4 are pressure-fed to the feed pipe 5 via the sub fuel tank 45 due to a relative pressure difference between the two caused by a temperature difference between them. In the oil sump chamber 11, the fuel tank 4 and the sub fuel tank 45 corresponding to the DME fuel pressure-fed (reference symbol F) from the oil sump chamber 11 to the fuel injection nozzle 9 by the injection pump element 2 through the injection pipe 3 are provided. It will be supplied via. Also,
The DME fuel overflowing from the fuel injection nozzle 9 is returned to the feed pipe 5 via the nozzle return pipe 7 and not supplied to the fuel tank 4 as in the conventional case, and is again supplied to the oil reservoir chamber 11.

FIG. 12 is a schematic block diagram showing a third embodiment of the DME fuel supply device 100 according to the present invention. The gas phase portion 4b is fed to the feed pipe 5 before the residual fuel recovery operation after the diesel engine is stopped. It shows a state in which the two are communicated with each other.

Similarly to the second embodiment, when the diesel engine is stopped, the three-way electric valve 31 is turned on to cut off the communication between the liquid phase portion 4a of the fuel tank 4 and the feed pipe 5, and the fuel tank 4 is closed. When the gas phase portion 4b of 4 and the feed pipe 5 are communicated with each other, the gaseous DME fuel of the gas phase portion 4b is delivered through the path indicated by the symbol K. And 3-way solenoid valve 3
The DME fuel in the feed pipe 5 on the oil reservoir chamber 11 side from 1 and the DME fuel filled in the refrigerant supply pipe 51 are supplied to the fuel tank by the electric compressor 23 through the fuel cooler 6 along the route indicated by the symbol L. Recovered to 4.

FIG. 13 is a schematic configuration diagram showing a third embodiment of the DME fuel supply device 100 according to the present invention, showing a residual fuel recovery operation after the diesel engine is stopped.

Similar to the first and second embodiments described above,
DM vaporized in the cylinder after the diesel engine stopped
The oil reservoir chamber 11, the injection pipe 3, the nozzle return pipe 7, and the refrigerant supply pipe 51 are filled with E fuel to prevent abnormal combustion such as knocking that occurs when the diesel engine is restarted. The remaining DME fuel is recovered in the fuel tank 4 by the "residual fuel recovery means". "Residual fuel recovery means" is 3
The solenoid valve 21 (communication path switching means) and the electric compressor 23 are included. After stopping the diesel engine,
When the 3-way solenoid valve 21 is turned off, the electric compressor 23 causes the oil sump chamber 11, the injection pipe 3, the nozzle return pipe 7, and the refrigerant supply pipe 51.
The DME fuel that has been filled into the fuel tank 4 is recovered in the fuel tank 4 through the path indicated by the symbol J. When the three-way solenoid valve 22 is turned off, the recovered DME fuel is cooled by the cooler 42 in the first return path (path indicated by the symbol H) and then recovered in the fuel tank 4.

In this way, the DME fuel can be supplied from the fuel tank to the oil reservoir without using a drive means such as a feed pump. In addition, the sub fuel tank 45
Since the capacity is smaller than that of the fuel tank 4, the pressurization time by the electric compressor 23 can be shortened, so that the time for charging the DME fuel into the oil reservoir 11 by the pressing force of the electric compressor 23 can be shortened. The capacity of the sub fuel tank 45 is equal to that of the oil sump chamber 11, the injection pipe 3, the nozzle return pipe 7, and the refrigerant supply pipe 5.
In the range in which 1 can be filled with DME fuel,
It can be said that the smaller the capacity, the more quickly the DME fuel can be filled, which is preferable.

Further, as a fourth embodiment, the common rail type of the DME fuel supply device 100 in the third embodiment can be mentioned. FIG. 14 is a schematic configuration diagram showing a fourth embodiment of the DME fuel supply device 100 according to the present invention. In this way, the injection pump 1
The present invention can also be implemented in the common rail type DME fuel supply device 100 in which the DME fuel that is pressure-fed from is supplied through the common rail 91 to which the fuel injection nozzles 9 are connected. Is what you can get.

The invention of the present application is not limited to the above embodiments, and various modifications can be made within the scope of the invention described in the claims, and these are also included in the scope of the invention of the present application. Needless to say.

[0079]

According to the present invention, there is provided a DME fuel supply device for a diesel engine capable of supplying DME fuel from a fuel tank to an oil sump chamber of an injection pump without using a driving means such as a feed pump. can do.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a first embodiment of a DME fuel supply device according to the present invention.

FIG. 2 is a schematic configuration diagram showing a first embodiment of the DME fuel supply device according to the present invention, showing a state when the diesel engine is stopped.

FIG. 3 is a schematic configuration diagram showing a first embodiment of a DME fuel supply device according to the present invention, showing a state where DME fuel is filled.

FIG. 4 is a schematic configuration diagram showing a first embodiment of a DME fuel supply device according to the present invention, showing a state during operation of a diesel engine.

FIG. 5 is a schematic configuration diagram showing a first embodiment of the DME fuel supply device according to the present invention, and showing a residual fuel recovery operation after the diesel engine is stopped.

FIG. 6 is a schematic configuration diagram showing a second embodiment of the DME fuel supply device according to the present invention.

FIG. 7 is a schematic configuration diagram showing a second embodiment of the DME fuel supply device according to the present invention, showing a state where the gas phase portion is communicated with the feed pipe before the residual fuel recovery operation after the diesel engine is stopped. It is shown.

FIG. 8 is a schematic configuration diagram showing a third embodiment of the DME fuel supply device according to the present invention.

FIG. 9 is a schematic configuration diagram showing a third embodiment of the DME fuel supply device according to the present invention, showing a state when the diesel engine is stopped.

FIG. 10 is a schematic configuration diagram showing a third embodiment of the DME fuel supply device according to the present invention, showing a state where DME fuel is filled.

FIG. 11 is a schematic configuration diagram showing a third embodiment of the DME fuel supply device according to the present invention, showing a state during operation of a diesel engine.

FIG. 12 is a schematic configuration diagram showing a third embodiment of the DME fuel supply device according to the present invention, showing a state in which the gas phase portion is communicated with the feed pipe before the residual fuel recovery operation after the diesel engine is stopped. It is shown.

FIG. 13 is a schematic configuration diagram showing a third embodiment of the DME fuel supply device according to the present invention, showing a residual fuel recovery operation after the diesel engine is stopped.

FIG. 14 is a schematic configuration diagram showing a fourth embodiment of the DME fuel supply device according to the present invention.

[Explanation of symbols]

1 injection pump 2 Injection pump element 3 injection pipes 4 fuel tank 5 feed pipe 6 Fuel cooler 7 nozzle return pipe 8 Return pipe 9 Fuel injection nozzle 11 oil reservoir 12 cam room 13 Oil separator 14 Check valve 15 Fuel vaporizer 16 Refrigerant supply pipe open / close solenoid valve 21 3-way solenoid valve (communication path switching means) 22 3-way solenoid valve (return path switching solenoid valve) 23 Electric compressor 31 3-way solenoid valve (gas-phase fuel delivery means) 45 Sub fuel tank 51 Refrigerant supply pipe

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Shunju Noda             3-13-26, Yumichocho, Higashimatsuyama City, Saitama Prefecture             Expression company Bosch Automotive System             Higashi Matsuyama Factory (72) Inventor Yukihiro Hayasaka             3-13-26, Yumichocho, Higashimatsuyama City, Saitama Prefecture             Expression company Bosch Automotive System             Higashi Matsuyama Factory

Claims (11)

[Claims] 1. An injection pump for delivering DME fuel supplied from a fuel tank via a feed pipe to a fuel injection nozzle of a diesel engine at a predetermined timing and at a predetermined amount, to an injection pipe. The DME overflowing from the fuel injection nozzle
A nozzle return pipe for returning fuel to the feed pipe, an oil reservoir fuel cooling device for cooling the DME fuel in the oil reservoir, and an oil reservoir fuel temperature detection for detecting the temperature of the DME fuel in the oil reservoir. Means for adjusting the temperature of the DME fuel in the oil reservoir to a temperature lower than the temperature of the DME fuel in the fuel tank by the oil reservoir fuel cooling device; DME fuel supply device for a diesel engine, comprising: a fuel supply unit that supplies the DME fuel in the fuel tank to the oil reservoir by a pressure difference between 2. The oil reservoir fuel cooling device according to claim 1, wherein the DME fuel in the oil reservoir is cooled by a cooling cycle using the DME fuel as a refrigerant. A DME fuel supply device for a diesel engine, comprising a fuel cooler that cools the DME fuel in the oil sump chamber by utilizing heat of vaporization caused by the vaporization of. 3. The fuel cooling system according to claim 2, wherein the oil reservoir fuel cooling device vaporizes the DME fuel flowing through the feed pipe and the DME fuel flowing through the feed pipe to cool the fuel. A fuel vaporizer to be sent to the reactor, and a refrigerant supply pipe opening / closing solenoid valve for opening / closing the refrigerant supply pipe, and configured to be controlled by controlling the opening / closing of the refrigerant supply pipe opening / closing solenoid valve, DME fuel supply system for diesel engines. 4. The oil separator according to claim 3, which separates the DME fuel mixed in the lubricating oil in the cam chamber, which is a dedicated lubricating system separated from the lubricating system of the diesel engine, and the oil separator. And an electric compressor that pressurizes the separated DME fuel and sends it to the fuel tank, and the DME fuel supplied from the refrigerant supply pipe to the oil reservoir fuel cooling device is
A DME fuel supply device for a diesel engine, which is configured to be delivered to the fuel tank by the electric compressor. 5. The DME fuel supply device for a diesel engine according to claim 4, further comprising a fuel tank internal temperature adjusting means for adjusting the internal temperature of the fuel tank. 6. The fuel tank internal temperature control means according to claim 5, wherein the DME fuel delivered from the electric compressor is cooled via an air-cooling cooler and then delivered to the fuel tank. Return path, a second return path through which the DME fuel sent from the electric compressor is sent to the fuel tank without passing through the air-cooling cooler, the first return path, and the second The temperature inside the fuel tank is adjusted by controlling a return path switching electromagnetic valve that switches between a return path, a fuel tank internal temperature detecting unit that detects a temperature inside the fuel tank, and the return path switching electromagnetic valve. A DME fuel supply device for a diesel engine, comprising: a fuel tank temperature control unit. 7. The method according to any one of claims 1 to 6,
After the diesel engine is stopped, the DME fuel remaining in the oil sump chamber of the injection pump and the nozzle return pipe is provided with residual fuel recovery means capable of recovering to the fuel tank. DME fuel supply system for diesel engine. 8. The residual fuel recovery means according to claim 7, wherein an inlet side of the oil reservoir communicating with the feed pipe and a communication path of the nozzle return pipe are connected to each other.
The communication path switching means for switching from the feed pipe to the residual fuel recovery pipe communicating with the inlet side of the electric compressor is provided, and the DME fuel remaining in the oil sump chamber of the injection pump and the nozzle return pipe. Is configured to be collected in the fuel tank by the electric compressor. 9. The gaseous DME fuel according to claim 8, wherein communication between the liquid phase portion of the fuel tank and the feed pipe is cut off, and the gas phase portion of the fuel tank and the feed pipe are communicated with each other. Of a diesel engine, characterized in that it comprises a gas-phase fuel delivery means for delivering
E fuel supply device. 10. The sub-fuel tank having a smaller capacity than that of the fuel tank is provided between the fuel tank and the feed pipe according to claim 1, and the diesel engine is started. Occasionally, the communication between the fuel tank and the sub-fuel tank is cut off, and the gas-phase portion of the sub-fuel tank and the outlet side of the electric compressor are made to communicate with each other, so that the electric-phase compressor causes A DME fuel supply device for a diesel engine, characterized in that the DME fuel is supplied from the pressurized sub fuel tank to the oil reservoir. 11. The D discharged from the injection pump according to any one of claims 1 to 10.
The ME fuel is supplied to the common rail and is delivered from the common rail to each fuel injection nozzle.
A DME fuel supply device for a diesel engine, which is characterized in that