The invention relates to a system for the delivery of a fluid.
In today's automotive engine systems, there is an increased demand for low cost, direct injection. In common rail injection systems, the fuel is delivered by means of a high pressure pump from a fuel tank to a fuel rail which serves as a storage reservoir for the fuel. The fuel is under high pressure in the fuel rail (or common rail) and can be injected directly into the cylinders via injection valves connected to the rail.
In GB 818 197 A a multi-cylinder internal combustion engine is described which comprises a single fuel pump cylinder being connected via a delivery conduit with a chamber to collect pressurized fuel.
It is desirable to provide a system for the delivery of a fluid which is cost-effective.
According to an aspect of the invention a system for the delivery of a fluid comprises a high pressure pump. The high pressure pump comprises a pump body. The high pressure pump further comprises a piston. The piston is axially movable within the pump body and comprises a first part and a second part. The first part is arranged within the pump body and the second part is arranged outside the pump body. The pump body is couplable with a combustion engine such that the second part of the piston extends into the combustion engine. The pump body comprises one single fluid outlet.
The system further comprises a fluid distributor that is directly connected with the pump body. The fluid distributor comprises a fluid inlet that is coupled with the fluid outlet of the pump. The distributor is provided with as many fluid outputs as the combustion engine comprises cylinders. The distributor is designed for coupling each fluid output directly with one cylinder of the combustion engine via a pipe.
The pump body is couplable with the combustion engine, particularly with an engine block or with a cylinder head of the combustion engine, and when the pump body is coupled with the combustion engine the second part of the piston is arranged such that it is axially movable in an opening of the engine block of the combustion engine. The high pressure pump is a plug-in pump. The high pressure pump is couplable directly in the engine block and mountable with the engine block.
According to further aspects, the piston is coupled with a roller tappet. The roller tappet is couplable with the cam or crank or balancer shaft of the combustion engine. The cam or crank or balancer shaft is arranged to move the roller tappet and the piston. The roller tappet is in direct contact with the opening of the engine block. The roller tappet slides over the walls of the opening. In the opening in the engine block ensures the axial movement of the roller tappet.
Since the pump body is provided mainly for the guiding of the fluid and not for the guiding of the piston, the high pressure pump is provided with less weight and is very compact. Further, the pump is cost-effective. With the high pressure pump a direct coupling of the pump with injectors for injecting fluid into the combustion chambers is possible.
There is no common rail arranged hydraulically between the injectors and the pump. The pump is designed such that each injector comprises its own fluid delivery path from the pump to the injector. Outside the pump the injectors are hydraulically independent from each other.
According to a further aspect of the invention, the fluid distributor surrounds one single fluid inlet and two or three fluid outlets. The fluid inlet and the fluid outlets each are hydraulically coupled with each other.
According to further aspects, the pump comprises a pressure sensor coupled with the fluid distributor for determining a value of the fluid pressure at the fluid outlets. Thus, the pump is arranged to provide a given value for the pressure for the injectors precisely.
According to further aspects of the invention the pump is coupled upstream with an electrically driven pump. For example, the electrically driven pump is an in-tank pump that is arranged inside a fluid tank. For example, the system comprises no further internal transfer pump.
The system is a low-cost and low-weight compact pump system. There is no need for a common rail between the high pressure pump and the injectors. The injectors are fed directly by the pump. The pump is designed such that each injector comprises its own fluid delivery path from the pump to the injector. Outside the pump the injectors are hydraulically independent from each other. Since the high pressure pump and the fluid distributor are separate parts, one layout of the pump is adaptable to different types of combustion engines due to the fluid distributor.
Reference will now be made in detail to the preferred embodiments, examples of which are illustrated in the accompanying drawings. The same elements, elements of the same type and elements having the same effect may be provided with the same reference symbols in the figures.
The high pressure pump 100 comprises a pump body 101 that surrounds openings for the guiding of fluid. The pump body 101 comprises a fluid inlet 112. The fluid inlet is couplable with an electric pump. The electric pump feeds the fluid to the inlet 112 of the pump body 101. A digital inlet valve 130 is coupled to the pump body 101.
A piston 102 is axially movable relative to the pump body 101 in a piston chamber 111. Due to the movement of the piston 102 relative to the pump body 101 fluid is sucked in through the inlet 112 into the pump body 101 and ejected through fluid outlet 122.
The piston comprises a first part 103 that is arranged within the pump body 101. The first part 103 is at least partly in contact with the fluid during operation of the pump 100. The piston 102 comprises a second part 104 that is arranged outside the pump body 101.
The second part 104 is coupled with a roller tappet 117. The roller tappet 117 is coupled to a drive shaft 127 of a combustion engine. The drive shaft 127 may be a cam or a crank or a balancer shaft for the movement of the roller tappet 117 and the piston 102 axially relative to the pump body 101.
The pump body 101 is coupled to an engine block 129 of the combustion engine. The engine block 129 surrounds an opening 128. The roller tappet 117 and the second part 104 of the piston 102 are arranged in the opening 128. The roller tappet 117 is in direct contact with the engine block 129. The roller tappet 117 and the drive shaft 127 are lubricated with engine oil.
The pump 100 comprises one single fluid outlet 122 that is directly connected with a fluid distributor 123. The fluid distributor 123 comprises one fluid inlet 124. The fluid distributor 123 comprises as many fluid outlets 105, 106, 107 as the combustion engine comprises cylinders. For example, the fluid distributor 123 comprises one outlet 105. According to further aspects the fluid distributor 123 comprises two fluid outlets 105, 106. According to further aspects, the fluid distributor 123 comprises three fluid outlets 105, 106, 107. According to further aspects, the fluid distributor 123 comprises more than three fluid outlets 105, 106, 107, for example four or more fluid outlets.
Each fluid outlet 105, 106, 107 is connectable to a pipe. Each pipe is coupled with an injector. The pump 100 delivers fluid to the injectors via the fluid distributor 123. The injectors are arranged to inject the fluid into combustion chambers of the combustion engine.
One injector of the injectors is arranged in one combustion chamber respectively. There is no common rail between the fluid distributor 123 and the injectors. The injectors each are directly coupled with the fluid distributor 123 via the pipes. The fluid distributor 123 is screwed directly on the pump housing 101 by a coupling nut 126. A coupling connector 125 connects the
fluid distributor 123 and the pump housing 101 hydraulically. A pressure sensor 116 is arranged at the fluid distributor 123 for determining the value of the fluid pressure at the fluid outlets 105, 106, 107.
Each fluid outlet 105, 106, 107 is connected to a pipe as exemplarily shown for three outputs in
One injector of the injectors 113, 114, 115 is arranged in one combustion chamber respectively. There is no common rail between the pump 100 and the injectors 113, 114 and 115. The injectors 113, 114, 115 each are directly coupled with the pump 100 via the pipes 108, 109, 110.
According to further aspects, the pump 100 comprises a volume control valve for controlling the volume of fluid delivered to the combustion engine.
The pump 100 is installed directly in the engine block 129. The roller tappet 117 slides over the walls of the engine block 129 in the opening 128. The opening 128 ensures the axial movement of the roller tappet 117. Thus, a lighter and compact system for the delivery of the fluid is provided. Since there is no need for a common rail, the system is cost-effective. An internal transfer pump may be replaced by the electric in-tank pump that is hydraulically coupled to the inlet 112 of the pump body 101.
According to further aspects, the pump 100 comprises a volume control valve for controlling the volume of fluid delivered to the combustion engine.
The pump 100 is installed directly in the engine block 129. The roller tappet 117 slides over the walls of the engine block 129 in the opening 128. The opening 128 ensures the axial movement of the roller tappet 117. Thus, a lighter and compact system for the delivery of the fluid is provided. Since there is no need for a common rail, the system is cost-effective. An internal transfer pump may be replaced by the electric in-tank pump that is hydraulically coupled to the inlet 112 of the pump body 101. The high pressure pump 100 and the distributor 123 form an inseparable assembly in a ready for use state. The high pressure pump 100 is directly integrated with the fluid distributor 123 and thus, a high pressure pipe line connecting between the pump and the distributor can be omitted.
This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.