Internal-combustion engines – Water and hydrocarbon
Reexamination Certificate
1999-12-28
2001-05-01
Dolinar, Andrew M. (Department: 3747)
Internal-combustion engines
Water and hydrocarbon
C123S299000, C123S575000
Reexamination Certificate
active
06223699
ABSTRACT:
The invention relates to a fuel injector for an internal combustion engine for fuel/emulsion operation.
Fuel/emulsion operation is being used increasingly in internal combustion engines, especially large-volume diesel engines, in which pure fuel or an emulsion composed of fuel and an added fluid that can be emulsified with air is burned depending on the operating and load state of the engine. When diesel fuel is used, water in particular is used as the added fluid. The emulsion is preferably produced in the fuel injector of the engine by intensive mixing of fuel and added fluid. One disadvantage of emulsion operation is that during operating pauses, water from the emulsion remains in the feed line and inside the fuel injector, causing undesired corrosion there.
A fuel injector for an internal combustion engine for fuel/emulsion operation is known from DE 44 35 823 C1 of Applicant, in which the fuel and the added fluid used to form the emulsion are supplied through respective supply channels in parallel to a mixing chamber provided in the fuel injector and are intimately mixed with one another using the kinetic flow energy of the fluid flows supplied. No measures are provided in this case that prevent the water contained in the emulsion from remaining during operating pauses and thus possibly producing corrosion.
An internal combustion engine is known from EP 0 5 53 364 A1 for fuel/emulsion operation in which the fuel injector has supply channels for parallel feed of pure fuel and a flow of fuel and water supplied in layers to a mixing chamber provided in the fuel injector. Here again, no measures are provided in the fuel injector to prevent water from remaining and thus causing corrosion in the fuel injector.
SUMMARY OF THE INVENTION
The goal of the invention is to provide a fuel injector for an internal combustion engine for fuel/emulsion operation in which corrosion by the water used to form the emulsion is prevented.
This goal is achieved by the fuel injector of the present invention.
The invention provides a fuel injector for an internal combustion engine for fuel/emulsion operation which has an injection nozzle formed by an nozzle needle and a nozzle needle cone for injecting fuel into the combustion chamber of the internal combustion engine in response to actuation of the nozzle needle. The fuel injector also has a fuel volume formed by a nozzle chamber surrounding the nozzle needle and a mixing chamber connected with the nozzle chamber, as well as a first fuel supply channel terminating in the mixing chamber to supply fuel under high pressure delivered from a high-pressure line, into the fuel volume and a second fuel supply channel likewise terminating in the mixing chamber for parallel supply of an added fluid flow, especially water, under high pressure that forms an emulsion with the fuel, into the fuel volume, as well as an added fluid supply channel that serves to supply the added fluid to the second fuel supply channel during pauses in injection. A switching valve device serves to control the amount of fluid supplied to the first and second fuel supply channels. According to the invention, provision is made such that the second fuel supply channel can be connected optionally by the switching valve device for supplying fuel with the high-pressure line supplying the fuel, and that the added fluid supply channel that serves to supply the added fluid to the second fuel supply channel terminates downstream of the switching valve device in the second fuel supply channel in such fashion that a volume V of added fluid that is delivered during an injection pause from the added fluid supply channel to the second fuel supply channel, during a subsequent injection phase of the fuel under high pressure delivered through the switching valve device, is completely injected into the combustion chamber of the internal combustion engine.
The advantage of the fuel injector according to the invention is that the second fuel supply channel as well as the fuel volume of the injector are completely flushed by fuel supplied through the second fuel supply channel so that during operating pauses, no emulsion-containing water remains in the fuel injector that could cause corrosion.
According to one embodiment of the invention, provision is made such that the first fuel supply channel or the second fuel supply channel can be connected by the switching valve device with a fuel return line through which compressed fluid flows from the second fuel supply channel during the supply of added fluid from the added fluid supply channel.
According to one characteristic of the invention, provision is made such that a throttle device is provided in the second fuel supply channel downstream of the switching valve device that limits the through flow of fuel. Such a throttle device has the advantage that the quantity of fuel that flows through the second fuel supply channel can be controlled in simple fashion.
A throttle device of this kind advantageously can be formed by a check valve that opens in the direction of the injection flow.
According to another characteristic of the invention, provision is made such that a throttle device that limits the through flow of fuel is also provided in the first fuel supply channel downstream of the switching valve device.
It is especially advantageous if, in both the first and the second fuel supply channels, throttle devices are provided that are so dimensioned that the quantity of fuel flowing through the second fuel supply channel is sufficient to deliver the quantity V of added fluid present in the second fuel channel completely into the mixing chamber, and that the quantity of fuel flowing through both fuel channels is sufficient to force the amount of fuel present in the fuel volume of the injector completely out of the injector. For this purpose, both throttle devices can be designed to be adjustable.
Advantageously, provision is made such that the mixing chamber is designed as an annular chamber surrounding the nozzle needle, that the two fuel supply channels terminate on opposite sides in the mixing chamber, and that the added fluid supply channel terminates close to the mixing chamber in the second fuel supply channel. This ensures that during the injection pause, accumulated water, regardless of the quantity of water, is conveyed each time at the beginning of the injection phase into the mixing chamber and forms an emulsion together with the fuel introduced through the first fuel supply channel.
Advantageously, the two fuel supply channels in the fuel injector run essentially parallel to the lengthwise axis of the injector on opposite sides of the nozzle needle.
According to one preferred embodiment of the invention, the first fuel supply channel can be connected by the switching valve device with a fuel return line. At the same time, the second fuel supply channel branches off from the first fuel supply channel downstream of the switching device and upstream of the throttle device provided in the first fuel supply channel, so that the flow of fuel supplied by the switching device from the high-pressure injection line to the first fuel supply channel is divided between the first and second fuel supply channels. The added fluid supply channel terminates downstream of the throttle device provided in the second fuel supply channel. The throttle device, in this embodiment is designed either as an adjustable throttle device or as a check valve that opens in the injection direction, with a corresponding throttle effect.
According to another advantageous embodiment of the invention, provision is made such that the switching valve device is designed as a 3/2-way valve which, during injection pauses, blocks the first fuel supply channel and connects the second fuel supply channel with the return line, and which during the injection phase connects both fuel supply channels with the high-pressure line that supplies the fuel.
REFERENCES:
patent: 4831970 (1989-05-01), Caputo
patent: 5170751 (1992-12-01), Tosa et al.
patent: 5174247 (1992-12-01), Tosa et al.
patent: 552
Danckert Bernd
Donauer Georg
Castro Arnold
Dolinar Andrew M.
Evenson, McKeown, Edwards & Lenahan P.L.L.C.
MTU Motoren-Und Turbinen-Union Friedrichshafen GmbH
LandOfFree
Injector for an internal combustion engine working with... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Injector for an internal combustion engine working with..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Injector for an internal combustion engine working with... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2543886