Patent Application
20180223786
The invention relates to a pump device, a fuel supply device, and a mixing device, in particular for a motor vehicle.
A pump device, and a fuel supply device for an internal combustion engine, in particular of a motor vehicle, already emerge, so as to be known, for example from US 2012/0312278 A1. The fuel supply device serves for supplying fuel, in particular liquid fuel, to the internal combustion engine. The fuel supply device comprises a first injection device for effecting a direct injection of fuel. This means that the internal combustion engine has at least one combustion chamber into which the fuel is directly injected by means of the first injection device.
The fuel supply device furthermore comprises a second injection device, which is provided in addition to the first injection device, for effecting an induction pipe injection of fuel. During the course of the intake pipe injection of fuel, which is also referred to as intake pipe injection, the fuel is introduced, in particular injected, into the internal combustion engine at a location arranged upstream of the combustion chamber. The location is arranged for example in an intake pipe, through which air may flow, of the internal combustion engine, and upstream of an inlet valve of the internal combustion engine.
The fuel supply device furthermore comprises the abovementioned high-pressure fuel pump, by means of which the fuel is supplied to the first injection device. This means that the fuel is conveyed to the first injection device by means of the high-pressure fuel pump. The fuel supply device furthermore comprises a low-pressure fuel pump for conveying the fuel to the high-pressure fuel pump. By means of the low-pressure fuel pump, the fuel is conveyed for example at a first pressure. In other words, by means of the low-pressure fuel pump, a first pressure of the fuel that is conveyed by means of the low-pressure fuel pump is effected.
By means of the high-pressure fuel pump, the fuel is conveyed for example at a second pressure that is higher than the first pressure. In other words, by means of the high-pressure fuel pump, a second pressure of the fuel that is higher than the first pressure is effected. In this way, it is for example possible for the first injection device to be supplied with the second pressure that is higher than the first pressure, where the second injection device is supplied with the first pressure.
The high-pressure fuel pump has at least one low-pressure inlet via which fuel is fed to the high-pressure fuel pump from the low-pressure fuel pump. This means that at least a part of the fuel conveyed by means of the low-pressure fuel pump is fed via the low-pressure inlet to the high-pressure fuel pump.
The high-pressure fuel pump furthermore has at least one low-pressure outlet for conducting fuel conveyed by means of the low-pressure fuel pump and fed via the low-pressure inlet to the high-pressure fuel pump out of the high-pressure fuel pump. This means that at least a part of the fuel that flows via the low-pressure inlet into the high-pressure fuel pump may flow out of or away from the high-pressure fuel pump via the low-pressure outlet, where, for example, the fuel flowing through the low-pressure outlet is at the first pressure effected by means of the low-pressure fuel pump. Thus, for example, the fuel flowing through the low-pressure outlet is not compressed by means of the high-pressure fuel pump.
Furthermore, the device comprises at least one low-pressure port for conducting fuel conveyed by means of the low-pressure fuel pump to the second injection device which is provided in addition to the first injection device. This means that the fuel that is for example at the first pressure is conducted by means of the low-pressure port to the second injection device, such that the second injection device is supplied via the low-pressure port with fuel that is in particular at the first pressure.
Furthermore, WO 2012/004084 A1 discloses a fuel system for an internal combustion engine, having a low-pressure conveying device which conveys at least indirectly to at least one low-pressure injection device. The fuel system furthermore comprises a high-pressure conveying device for the fuel, which high-pressure conveying device has a drive region and a conveying region and conveys at least indirectly to at least one high-pressure injection device. It is provided here that the fuel is conveyed from the low-pressure conveying device firstly into the drive region of the high-pressure conveying device and from there onward to the low-pressure injection device and/or to the conveying region of the high-pressure conveying device.
It is an object of the present invention to provide a pump device, a fuel supply device and a mixing device, by means of which a particularly advantageous fluid supply may be realized.
The object is achieved by means of a pump device having the features of patent claim 1, by means of a fuel supply device having the features of patent claim 12 and by means of a mixing device having the features of patent claim 13. Advantageous embodiments with expedient refinements of the invention are specified in the further claims.
According to the invention, to further develop a pump device of the type specified in the preamble of patent claim 1 such that it is possible to realize a particularly advantageous fluid supply, in particular a particularly advantageous supply of the fuel, which constitutes a fluid, to the internal combustion engine, at least one mixing region is provided for mixing the fuel flowing through the low-pressure outlet with fuel fed to the mixing region from the low-pressure fuel pump upstream of the low-pressure inlet, and thus upstream of the high-pressure fuel pump. Here, the low-pressure port is fluidically connected to the mixing region, and the low-pressure inlet is supplied with fuel from the mixing region.
The mixing region is thus fluidically connected to the low-pressure inlet and to the low-pressure outlet, such that at least a part of the fuel flowing through the low-pressure outlet is or may be fed to the mixing region. In addition to this fuel, fuel is fed to the mixing region from the low-pressure fuel upstream of the low-pressure inlet, that is to say at a location upstream of the high-pressure fuel pump, which fuel has therefore not flowed through the high-pressure fuel pump, that is to say through the low-pressure inlet or the low-pressure outlet. The additional fuel which is fed to the mixing region upstream of the high-pressure fuel pump, and which thus differs from the fuel flowing through the low-pressure outlet, is also referred to as fresh fuel, because the fresh fuel has not yet flowed through the high-pressure fuel pump.
The fresh fuel is thus fed to the mixing region upstream of the high-pressure fuel pump or is fed to the mixing region upstream of the high-pressure fuel pump, where the fuel flowing through the low-pressure outlet may be fed or is fed to the mixing region downstream of the low-pressure outlet and thus downstream of the high-pressure pump. In the mixing region, the fresh fuel may mix with the fuel from the low-pressure outlet, where it may be provided that fuel from the mixing region, and thus a part of the mixed fuel, is fed to the low-pressure port. Since the fuel flowing through the low-pressure outlet, which differs from the fresh fuel, flows through the high-pressure pump, the high-pressure fuel pump may hereby be cooled, such that the fuel flowing through the low-pressure outlet is at a first temperature.
The fresh fuel, which is fed to the mixing region from the low-pressure fuel pump upstream of the low-pressure outlet, is at a second temperature which is lower than the first temperature, because the fresh fuel has not yet flowed through the high-pressure fuel pump. As a result of the mixing of the fuel flowing through the low-pressure outlet with the fresh fuel, the temperature of the fuel overall may be kept particularly low. As a result, the internal combustion engine is supplied with fuel which is at a particularly advantageous low temperature. In particular, by means of the mixing of the fuel flowing through the low-pressure outlet with the fresh fuel and by means of the possibly provided supply of fuel from the mixing region to the low-pressure port, a particularly advantageous dissipation of temperature or heat is realized, such that the high-pressure fuel pump is cooled in a particularly effective manner. In this way, overheating and resulting damage and failures of the high-pressure fuel pump is avoided, such that a reliable and thus advantageous supply of the fuel, which constitutes a fluid, to the internal combustion engine may be realized.
In an advantageous refinement of the invention, the low-pressure port is supplied with fuel from the mixing region. In this way, a particularly advantageous dissipation of heat is realized, such that the high-pressure fuel pump is cooled in a particularly effective manner. As a result, a reliable and advantageous supply of the fuel to the internal combustion engine may be realized.
It has proven to be particularly advantageous if the high-pressure fuel pump has a conveying element for conveying the fuel to the first injection device. For example, the high-pressure fuel pump comprises a pump housing, in which the conveying element is at least partially, in particular at least predominantly, accommodated. Here, the conveying element is movable, in particular movable in translational fashion, relative to the pump housing.
The high-pressure fuel pump furthermore has a compression chamber, the volume of which is variable by movement of the conveying element. The compression chamber is for example arranged in the pump housing. Furthermore, the high-pressure fuel pump comprises a collecting chamber which is arranged on a side of the conveying element averted from the compression chamber and which is variable in terms of its volume by movement of the conveying element and which serves for collecting fuel from the compression chamber. The collecting chamber is preferably arranged in the pump housing. Here, at least a part of the fuel flowing through the low-pressure inlet flows from the low-pressure inlet to the collecting chamber, circumventing the compression chamber. The fuel flows through the collecting chamber and then flows through the low-pressure outlet and into the mixing region. “Circumventing” is to be understood to mean that the fuel does not flow through the compression chamber, and is accordingly not compressed and conveyed by means of the conveying element. In this way, heat is discharged from the collecting chamber in an effective manner, such that the high-pressure fuel pump is cooled in an effective manner.
A further embodiment is distinguished by the fact that the mixing region has at least one first feed opening, by means of which the mixing region is fluidically connected to the low-pressure outlet and is supplied with the fuel flowing through the low-pressure outlet. Furthermore, the mixing region has at least one second feed opening, by means of which the mixing region is supplied with fuel from the low-pressure fuel pump, that is to say with the fresh fuel, upstream of the low-pressure inlet and thus upstream of the high-pressure fuel pump. The fresh fuel passing from or conveyed by the low-pressure fuel pump may flow through the second feed opening and flow via the second feed opening into the mixing region, such that the fresh fuel has not yet flowed through the low-pressure inlet and the low-pressure outlet or the high-pressure fuel pump.
Furthermore, the mixing region has at least one first discharge opening, via which fuel is fed from the mixing region to the low-pressure inlet. This means that at least a part of the fuel flowing through the low-pressure inlet is fed to the low-pressure inlet from the mixing region, where the mixing region is fluidically connected via the first discharge opening to the low-pressure inlet. The mixing region furthermore has at least one second discharge opening, via which the low-pressure port is fluidically connected to the mixing region, such that, for example, fuel is fed from the mixing region to the low-pressure port via the second discharge opening.
It is provided here that the feed openings and the discharge openings are respective openings which are spaced apart from one another, such that the mixing region has at least four openings. The first feed opening is in this case for example a first of the openings, the second feed opening is a second of the openings, the first discharge opening is a third of the openings, and the second discharge openings is the fourth opening. Here, the second opening is provided in addition to the first opening, where the third opening is provided in addition to the first opening and in addition to the second opening. Furthermore, the fourth opening is provided in addition to the first opening, in addition to the second opening and in addition to the third opening. Here, fuel may flow through the openings. By means of this design of the mixing region, the mixing region is supplied with the fuel in a particularly advantageous manner and in accordance with demand, where, furthermore, advantageous thorough mixing of the fuel in the mixing region may be realized. As a result, an advantageous dissipation of heat may be realized, such that the high-pressure fuel pump is cooled in an effective manner. It is thus possible to realize an advantageous supply of fuel to the internal combustion engine.
A further embodiment is distinguished by the fact that the second discharge opening is arranged upstream of the first feed opening in relation to a flow direction of the fuel from the second feed opening to the first discharge opening. Firstly, in this way, particularly advantageous cooling of the high-pressure fuel pump may be realized. Secondly, the low-pressure port and thus the second injection device is supplied with fuel in a particularly advantageous manner, because, for example, the temperature of the fuel fed to the second injection device via the low-pressure port is kept low.
To realize a particularly advantageous cooling of the high-pressure fuel pump and therefore to realize a particularly advantageous supply of the fuel to the internal combustion engine, it is provided in a further embodiment of the invention that the second discharge opening is arranged upstream of the first discharge opening, downstream of the second feed opening and downstream of the first feed opening in relation to a flow direction of the fuel from the second feed opening to the first discharge opening.
Here, it has proven to be particularly advantageous if the first feed opening is arranged upstream of the second discharge opening and upstream of the second feed opening in relation to the flow direction of the fuel from the second feed opening to the first discharge opening.
In one particularly advantageous embodiment of the invention, at least one of the feed openings and/or at least one of the discharge openings opens into a duct through which the fuel may flow. In other words, at least one of the stated openings opens into a duct through which the fuel may flow. Here, a valve element, in particular a check valve, is arranged in the duct. By means of the valve element, a flow of the fuel through the duct is influenced or stopped, such that, for example, undesired flows of the fuel is prevented by means of the valve element, in particular the check valve. For example, undesired flows of the fuel via the discharge openings into the mixing region, and undesired flows of the fuel out of the mixing region via the feed openings, is prevented, such that advantageous thorough mixing of the fuel may be realized, and a reliable supply of the fuel to the internal combustion engine may be ensured.
To be able to thoroughly mix the fuel in the mixing region in an advantageous and effective manner, it is provided in one advantageous embodiment of the invention that the mixing region is at least partially, in particular at least predominantly, of spherical form on the inner circumference. It is alternatively or additionally conceivable for the mixing region to have, at least in a partial region, a parallelogram-shaped or rectangular cross section.
If, for example, the low-pressure port is supplied with fuel from the mixing region, then it is preferably provided that the low-pressure port is designed to conduct at least a part of the fuel conveyed by means of the low-pressure fuel pump, which fuel is fed to the high-pressure fuel pump and flows through the low-pressure outlet, away from the high-pressure fuel pump to the second injection device. In this way, it is for example possible for the fuel conveyed by means of the low-pressure fuel pump, or at least a part of the fuel conveyed by means of the low-pressure fuel pump, to flow firstly through the mixing region, then subsequently through the low-pressure inlet, then subsequently through the low-pressure outlet, then subsequently through the mixing region again and then subsequently through the low-pressure port and to then flow to the second injection device, in particular while an injection of fuel effected by means of the first injection device is omitted and, if appropriate, an injection of fuel effected by means of the second injection device is performed. In this way, the high-pressure fuel pump is cooled by means of the fuel conveyed by the low-pressure fuel pump, even when the second injection device is activated, that is to say when fuel is injected by means of the second injection device and the first injection device is deactivated, that is to say an injection of fuel effected by means of the first injection device is omitted. In this way, overheating and resulting damage of the high-pressure fuel pump is reliably avoided.
According to the invention, to further develop a fuel supply device of the type specified in the preamble of patent claim 12 such that it is possible to realize a particularly advantageous fluid supply, in particular a particularly advantageous supply of the fuel, which constitutes a fluid, to the internal combustion engine, at least one mixing region is provided for mixing the fuel flowing through the low-pressure outlet with fuel (fresh fuel) fed to the mixing region from the low-pressure fuel pump upstream of the high-pressure fuel pump, where the low-pressure port is fluidically connected to the mixing region, and the low-pressure inlet is supplied with fuel from the mixing region. Advantages and advantageous embodiments of the high-pressure fuel pump according to the invention are to be regarded as advantages and advantageous embodiments of the fuel supply device according to the invention, and vice versa.
It is preferably provided here that the pump device of the fuel supply device according to the invention is a pump device according to the invention.
The invention also includes a mixing device, in particular for a motor vehicle, in particular a passenger motor vehicle. The mixing device has at least one mixing region for mixing at least one first fluid flow with at least one second fluid flow. The respective fluid flow is formed for example by at least one fluid, where the fluid may be a gas or preferably a liquid. The fluid is preferably an operating medium, in particular an operating liquid, of an internal combustion engine for driving a motor vehicle, where the fluid may be the fuel, in particular liquid fuel, mentioned in conjunction with the pump device according to the invention and the fuel supply device according to the invention.
The mixing region has at least one first inlet, at least one second inlet, at least one first outlet and at least one second outlet. The first inlet is for example the first feed opening mentioned above, where the second inlet is for example the abovementioned second feed opening. The first outlet is for example the first discharge opening mentioned above, where the second outlet is for example the abovementioned second discharge opening. The first fluid flow is fed to the mixing region via the first inlet. The second fluid flow is fed to the mixing region via the second inlet. Fluid is discharged from the mixing region via the first outlet, where fluid is discharged from the mixing region via the second outlet. For example, the fluid flows differ from one another in terms of at least one characteristic. The characteristic is for example a temperature of the respective fluid flow. It may be provided here that one of the fluid flows is warmer than the other fluid flow. It is preferably provided that the second fluid flow is colder than the first fluid flow.
In the case of the mixing device according to the invention, the second outlet is arranged upstream of the first inlet in relation to a flow direction of the fluid from the second inlet to the first outlet. The inlets and outlets are thus arranged in a particularly expedient manner in terms of flow, such that advantageous thorough mixing of the fluid flows may be realized. In particular, by means of the mixing device according to the invention, an advantageous dissipation of heat may be realized, such that, for example, a component, in particular the high-pressure fuel pump described above, is easily cooled in an effective manner.
Refinements of the mixing region of the pump device according to the invention or of the fuel supply device according to the invention mentioned with regard to the pump device according to the invention and the fuel supply device according to the invention are to be regarded as advantageous refinements of the mixing region of the mixing device according to the invention, and vice versa.
It has proven to be particularly advantageous if the mixing region has a rectangular, parallelogram-shaped and/or arcuate, in particular circular, cross section in at least one subregion on the inner circumference.
The invention also includes a vehicle, in particular a motor vehicle such as for example a passenger motor vehicle, having at least one high-pressure fuel pump according to the invention and/or having at least one fuel supply device according to the invention and/or having at least one mixing device according to the invention.
Further advantages, features and details of the invention will emerge from the following description of preferred exemplary embodiments and from the drawing. The features and combinations of features mentioned in the description above and the features and combinations of features mentioned in the description of the figures below and/or shown in the figures alone may be used not only in the respectively stated combination, but also in other combinations or alone without departing from the scope of the invention.
Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.
Exemplary embodiments of the invention will be explained in more detail hereunder by means of the schematic drawings. In the figures:
In the figures, identical or functionally identical elements are provided with identical reference signs.
The following description of the preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses.
The internal combustion engine has a multiplicity of combustion chambers in the form of cylinders, where the fuel is fed to the combustion chambers. Furthermore, air is fed to the combustion chambers, such that a fuel-air mixture is formed in the respective combustion chamber from the air and the fuel. The fuel-air mixture is burned, resulting in exhaust gas of the internal combustion engine.
The respective combustion chamber is assigned at least one outlet duct via which the exhaust gas is discharged from the combustion chamber. The outlet duct is assigned at least one gas exchange valve in the form of an outlet valve, where the outlet valve is movable between a closed position and at least one open position. In the closed position, the outlet duct is fluidically shut off by means of the outlet valve, such that the exhaust gas may not flow from the combustion chamber into the outlet duct. In the open position, the outlet valve opens up the outlet duct, such that the exhaust gas may flow from the combustion chamber into the outlet duct.
Furthermore, the respective combustion chamber is assigned at least one inlet duct, via which the air is fed to the combustion chamber. Here, the inlet duct is assigned at least one gas exchange valve in the form of an inlet valve, which is adjustable between a closed position and at least one open position. In the closed position, the inlet duct is fluidically shut off by means of the inlet valve, such that the air cannot flow from the inlet duct into the combustion chamber. In the open position, the inlet valve opens up the inlet duct, such that the air may flow through the inlet duct and may flow from the inlet duct into the combustion chamber.
The fuel supply device 12 comprises a first injection device 14, which is formed for example as a high-pressure injection device. Here, each combustion chamber is assigned an injection valve 16 of the first injection device 14. The first injection device 14 is in this case designed for effecting a direct injection of fuel, where the direct injection of fuel is also referred to as direct injection. During the course of the direct injection, the fuel is injected by means of the respective injection valve 16 directly into the respective combustion chamber, in particular cylinder. Here, the first injection device 14 comprises a fuel distribution element 18 which is common to the injection valves 16 and via which the fuel is supplied to the injection valves 16. The fuel distribution element 18 is also referred to as a rail, where the fuel distribution element 18 is referred to as a high-pressure rail if the first injection device 14 is formed as a high-pressure injection means. By means of the first injection device 14, the fuel is injected for example at a first pressure into the combustion chambers, where, for example, the fuel at the first pressure is accommodated in the fuel distribution element 18 and fed at the first pressure to the injection valves 16.
The fuel supply device 12 furthermore comprises a second injection device 20 which is provided in addition to the first injection device 14 and which is formed for example as a low-pressure injection device. The second injection device 20 is in this case designed for effecting an induction pipe injection of fuel, where the induction pipe injection of fuel is also referred to as induction pipe injection. Here, each combustion chamber is assigned at least one injection valve 22 of the second injection device 20.
The air is fed to the combustion chambers for example via an intake tract of the internal combustion engine, such that the intake tract may be flowed through by the air. The intake tract comprises for example an induction pipe, which is also referred to as induction module, intake module or air distributor. The intake tract may furthermore comprise the inlet ducts.
In the case of the induction pipe injection, the fuel is introduced, in particular injected, into the internal combustion engine, in particular into the intake tract, by means of the respective injection valve 22 at a location arranged upstream of the respective combustion chamber. In other words, the location at which the fuel is injected by means of the respective injection valve 22 is arranged upstream of the combustion chamber and in particular in the intake tract. The location may be arranged for example in the induction pipe or in the inlet duct. In particular, the respective location at which the fuel is injected by means of the respective injection valve 22 is arranged upstream of the respective inlet valve.
The second injection device 20 also comprises a fuel distribution element 24 which is common to the injection valves 22 and via which the fuel is supplied to the injection valves 22. Here, the fuel distribution element 24 is also referred to as rail. Since the second injection device 20 is formed for example as a low-pressure injection device, the fuel distribution element 24 is also referred to as low-pressure rail. By means of the second injection device 20, the fuel is injected for example at a second pressure that is lower than the first pressure. Here, the fuel at the second pressure may for example be accommodated or stored in the fuel distribution element 24 and fed at the second pressure to the injection valves 22. The fuel supply device 12 furthermore comprises a tank 26 in which the in particular liquid fuel is accommodated.
It is seen from
The fuel supply device 12 furthermore comprises a low-pressure fuel pump 28 which is provided in addition to the high-pressure fuel pump 10 and which serves for conveying the fuel from the tank 26 to the high-pressure fuel pump 10. This means that the fuel is conveyed from the tank 26 to the high-pressure fuel pump 10 by means of the low-pressure fuel pump 28. For example, the fuel is conveyed at a third pressure by means of the low-pressure fuel pump 28. This means that a third pressure of the fuel is effected for example by means of the low-pressure fuel pump 28, where the fuel is conveyed at the third pressure to the high-pressure fuel pump 10 by means of the low-pressure fuel pump 28. Here, the third pressure may correspond to the second pressure, such that, for example, the second pressure of the fuel is effected by means of the low-pressure fuel pump 28. In other words, the low-pressure fuel pump 28 may for example convey the fuel at the second pressure, which may correspond to the third pressure.
It is seen from
Since the fuel is fed to the high-pressure fuel pump 10, and in particular introduced into the high-pressure fuel pump 10, via the first low-pressure port 30 and in this case via the first duct 32 and the low-pressure inlet 31, the first low-pressure port 30 is also referred to as inflow. It is seen from
The high-pressure fuel pump 10 and thus the pump device 11 furthermore comprise at least one second low-pressure port 36, which has a duct 38 which may be flowed through by fuel. The second low-pressure port 36 forms a low-pressure outlet 37 of the high-pressure fuel pump 10, where the low-pressure outlet 37 is designed for conducting fuel conveyed by means of the low-pressure fuel pump 28 and fed via the low-pressure inlet 31 to the high-pressure fuel pump 10 out of the high-pressure fuel pump 10. This means that at least a part of the fuel that has flowed into the high-pressure fuel pump 10 via the low-pressure inlet 31 may, via the low-pressure outlet 37, be discharged from the high-pressure fuel pump 10 or conducted out of or discharged from the high-pressure fuel pump 10.
As already discussed, the fuel flowing through the duct 32 and thus through the low-pressure inlet 31 is at the second or third pressure, because it is conveyed by means of the low-pressure fuel pump 28. The fuel flowing through the low-pressure outlet 37 and thus through the duct 38 is at least substantially at the second or third pressure, because the fuel flowing through the low-pressure outlet 37 and thus through the duct 38 is not compressed, that is to say is not pressurized, by means of the high-pressure fuel pump 10. This means that a compression or pressurization, effected by the high-pressure fuel pump 10, of the fuel flowing through the low-pressure outlet 37 is omitted, such that the fuel flowing through the low-pressure outlet 37 flows from the low-pressure inlet 31 to the low-pressure outlet 37, and flows through the low-pressure outlet 37, without being compressed by means of the high-pressure fuel pump 10 in the process. As will be discussed in more detail below, it is conceivable for at least a part of the fuel at the second or third pressure flowing through the low-pressure outlet 37 to be conducted via the low-pressure outlet 37 to the second injection device 20, in particular to the fuel distribution element 24, such that the fuel at the second or third pressure is received and stored in the fuel distribution element 24.
The pump device 11 furthermore comprises a third low-pressure port 39 for conducting fuel conveyed by means of the low-pressure pump 28, in particular at the second or third pressure, to the second injection device 20. The low-pressure port 39 has a duct 41 through which the fuel may flow and which is fluidically connected to the low-pressure fuel pump 28. In this way, at least a part of the fuel conveyed by means of the low-pressure fuel pump 28 and at the second or third pressure is conducted via the low-pressure port 39 or the duct 41 to the second injection device 20, in particular to the fuel distribution element 24, and stored in the fuel distribution element 24, in particular at the second or third pressure.
Thus, the fuel at the third pressure or second pressure flows through the low-pressure port 39 or the duct 41. Altogether, it is evident that the fuel in the low-pressure inlet 31 and in the low-pressure outlet 37 and in the duct 41 is at the second pressure. In other words, the fuel flowing through the low-pressure inlet 31, the low-pressure outlet 37 and the duct 41 is at the second or third pressure which is effected by means of the low-pressure fuel pump 28, where a compression, effected by means of the high-pressure fuel pump 10, of the fuel flowing through the low-pressure inlet 31, the low-pressure outlet 37 and the duct 41 to a pressure higher than the second or third pressure is omitted.
The high-pressure fuel pump 10 has a low-pressure chamber 40 which may be flowed through by at least a part of the fuel fed to the high-pressure fuel pump 10 via the low-pressure inlet 31. The high-pressure fuel pump 10 furthermore comprises a first structural element in the form of a pump housing 42. Furthermore, the high-pressure fuel pump 10 has a conveying element for conveying at least a part of the fuel fed to the high-pressure fuel pump 10 via the low-pressure inlet 31, where the conveying element is in the present case formed as a piston 44. The piston 44 is also referred to as conveying piston, where the piston 44 has a first length region 46 and an adjoining second length region 48. The length region 46 has a first outer circumference, where the length region 48 has a second outer circumference which is shorter than the first outer circumference. Since the length regions have different outer circumferences, the piston 44 has a step. The piston 44 is thus formed as a stepped pin.
It is alternatively conceivable for the length regions 46 and 48 to have the same outer circumference, such that the piston 44 has no step.
The piston 44 is arranged at least partially in the pump housing 42, and in this case is movable relative to the pump housing 42, where the piston 44 is in the present case movable in translational fashion relative to the pump housing 42. The translational mobility of the piston 44 relative to the pump housing 42 is indicated in
The high-pressure fuel pump 10 furthermore comprises a second structural element for example in the form of a cover 54, which is formed separately from the pump housing 42 and which is connected to the pump housing 42 or held on the pump housing 42.
Furthermore, a drive element is provided in the form of a cam 56 which is illustrated particularly schematically in
Movement of the piston 44 in the direction of the cover 54 causes the volume of the compression chamber 52 to be decreased, whereby fuel accommodated in the compression chamber 52 is compressed, that is to say pressurized.
Movement of the piston 44 away from the cover 54 causes the volume of the compression chamber 52 to be increased, whereby fuel is drawn into the compression chamber 52. Here, it is provided in particular that the compression chamber 52 is fluidically connectable or connected to the low-pressure chamber 40, such that fuel may be or is drawn into the compression chamber 52 from the low-pressure chamber 40 by means of the piston 44.
The fuel that is drawn and thus flows from the low-pressure chamber 40 into the compression chamber 52 is at least a part of the fuel fed to the high-pressure fuel pump 10 or introduced into the high-pressure fuel pump 10 via the low-pressure inlet 31 (inflow), because at least a part of the fuel introduced via the inflow (low-pressure inlet 31) into the high-pressure fuel pump 10 may flow into the low-pressure chamber 40 and be drawn, or is drawn, from there into the compression chamber 52 by means of the piston 44.
As a result of the compression of the fuel by means of the piston 44, a fourth pressure of the fuel is effected or set by means of the high-pressure fuel pump 10, where the fourth pressure is higher than the second and the third pressure. For example, the fourth pressure corresponds to the first pressure, such that the first injection device 14, in particular the fuel distribution element 18, is supplied with the first pressure or fourth pressure by means of the high-pressure fuel pump 10.
It is seen from
Since each combustion chamber is assigned an injection valve 22 of the second injection device 20, multiple locations arranged upstream of the combustion chambers are provided at which fuel is injected by means of the second injection device 20. This type of induction pipe injection is also referred to as multi-port injection (MPI), such that the low-pressure port 39 is also referred to as MPI port.
Here, it is for example possible for at least one of the injection devices 14 and 20, in particular the first injection device 14, to be activated and deactivated according to demand. In the activated state of the injection device 14, the fuel is injected by means of the injection device 14 directly into the combustion chambers. In the deactivated state of the injection device 14, a direct injection of the fuel into the combustion chambers effected by means of the injection device 14 is omitted. Here, even in the deactivated state of the injection device 14, fuel conveyed by means of the low-pressure fuel pump 28, in particular at the second or third pressure, is fed to the high-pressure fuel pump 10 via the low-pressure inlet 31, where the fuel is thus at the third or second pressure, which is lower than the fourth or first pressure.
Since the fuel flowing through the low-pressure inlet 31 is not compressed by means of the high-pressure fuel pump 10 or has not yet been compressed by means of the high-pressure fuel pump 10, the fuel flowing through the inflow (low-pressure inlet 31) is at a low temperature, such that the high-pressure fuel pump 10, fuel flowing through the low-pressure inlet 31 and subsequently through the low-pressure outlet 37, is cooled, for example even when the injection device 14 is deactivated, by means of the fuel fed to the high-pressure fuel pump 10 via the low-pressure inlet 31 and flowing through the low-pressure outlet 37. For this purpose, at least a part of the fuel flowing through the low-pressure inlet 31 flows through the low-pressure outlet 37 and therefore not through the compression chamber 52, such that the high-pressure fuel pump 10 is cooled. This means that the fuel flowing through the low-pressure outlet 37 circumvents the compression chamber 52, that is to say does not flow through the compression chamber 52, or is not drawn into the compression chamber 52 by means of the piston 44.
On a side of the piston 44 averted from the compression chamber 52, a chamber 62 is provided which functions for example as a collecting chamber. The piston 44 is guided for example by means of a guide that is not shown in
If the piston 44 is moved in the direction of the cover 54 in particular by means of the cam 56, whereby the volume of the compression chamber 52 is decreased, the volume of the chamber 62 is increased. As a result, for example, fuel is drawn from the low-pressure chamber 40 into the chamber 62 via the stated fluidic connection. As already described above, at least a part of the fuel fed to the high-pressure fuel pump 10 via the low-pressure inlet 31 may flow into the low-pressure chamber 40, because the inflow, in particular the duct 32, is fluidically connected to the low-pressure chamber 40.
Fuel is thus conveyed back and forth between the chamber 62 and the low-pressure chamber 40 by movement of the piston 44. Furthermore, the low-pressure chamber 40 is for example fluidically connected to the low-pressure outlet 37, such that the fuel flowing through the low-pressure inlet 31 may flow via the low-pressure chamber 40, or through the latter, to the low-pressure outlet 37. In this way, heat is discharged from the high-pressure fuel pump 10, in particular from the piston 44, in a particularly advantageous manner, such that overheating and resulting damage of the high-pressure fuel pump 10 may be avoided.
As a result of fuel being drawn into the compression chamber 52 and/or into the chamber 62 and the fuel being conveyed out of the compression chamber 52 and/or out of the chamber 62, pulsations of the fuel may arise. It is conceivable here for a damping device to be arranged at least partially in the cover 54, by means of which damping device the stated pulsations of the fuel may be dampened. The cover 54 is thus for example also referred to as damper cover.
To now realize a particularly advantageous fluid supply in the form of a particularly advantageous supply of the fuel to the internal combustion engine, the pump device 11 comprises at least one mixing region 64 for mixing the fuel flowing through the low-pressure outlet 37 with fuel which is fed to the mixing region from the low-pressure fuel pump 28 upstream of the high-pressure fuel pump 10 and which is at the second or third pressure, where the low-pressure port 39 is fluidically connected to the mixing region 64, and where the low-pressure inlet 31 is supplied with fuel from the mixing region 64.
In other words, the mixing region 64 is fluidically connected to the low-pressure inlet 31 and fluidically connected to the low-pressure outlet 37. The mixing region 64 is assigned a low-pressure port 66, which has a duct 68 through which the fuel may flow. Furthermore, the mixing region 64 is assigned a low-pressure port 70, which has a duct 72 through which the fuel may flow. The ducts 32, 41, 68 and 72 are fluidically connected to the mixing region 64, where the ducts 68 and 72 open into the mixing region 64 and the ducts 32 and 41 branch off from the mixing region 64. In this way, it is for example possible for fuel to flow from the mixing region 64 into the duct 41, where fuel may flow from the mixing region 64 into the duct 32. Furthermore, the fuel flowing through the duct 68 may flow into the mixing region 64, where the fuel flowing through the duct 72 may also flow into the mixing region 64. Here, the duct 72 is arranged upstream of the mixing region 64, where the duct 68 is also arranged upstream of the mixing region 64.
From
The mixing region 64 is fluidically connected by means of the low-pressure port 70, in particular the duct 72, to the low-pressure fuel pump 28, such that the fuel conveyed by means of the low-pressure fuel pump 28 and thus at the second or third pressure is fed to the mixing region 64 via the duct 72 or the low-pressure port 70. The fuel flowing through the duct 72 is therefore at the second or third pressure effected by means of the low-pressure fuel pump 28. Furthermore, the fuel flowing through the duct 41 is at the second or third pressure because a compression, effected by means of the high-pressure fuel pump 10, of the fuel flowing through the duct 41 is omitted. The second injection device 20 may therefore be supplied with the fuel at the second or third pressure via the MPI port.
Since the duct 72 is arranged upstream of the high-pressure fuel pump 10, the fuel flowing through the duct 72 has not been compressed by means of the high-pressure fuel pump 10, such that the fuel flowing through the duct 72 is at a low temperature. The fuel flowing through the duct 72 is also referred to as fresh fuel. By contrast to this fresh fuel, the fuel flowing through the low-pressure outlet 37 and thus the duct 38 is at a higher temperature than the fuel flowing through the duct 72, because the fuel flowing through the duct 38 flows through the high-pressure fuel pump 10 and thus cools the latter, such that heat is transferred from the high-pressure fuel pump 10 to the fuel flowing through the duct 38. The fuel flowing through the duct 38 is therefore a hot medium, which is also referred to as purging medium or cooling medium. Since both the fresh fuel and the purging medium are fed to the mixing region 64, the fresh fuel may mix with the purging medium, such that excessive temperatures of the fuel may be avoided. Furthermore, a particularly advantageous dissipation of heat may be realized, such that the high-pressure fuel pump 10 is cooled in a particularly effective manner. As a result, a reliable supply of fuel to the internal combustion engine may be realized.
It is seen from the dashed line that the fuel flowing from the low-pressure inlet 31 to the low-pressure outlet 37 and flowing through the low-pressure outlet 37 flows through the chamber 62, and in so doing circumvents, that is to say does not flow through, the compression chamber 52. In this way, heat is dissipated from the region of the chamber 62 in a particularly effective manner. The region is for example a drive region, in which high levels of heat generation may occur. Since the fuel flows through the drive region, a large quantity of heat is dissipated from the drive region, such that the high-pressure fuel pump 10 is cooled.
The MPI port is therefore not supplied with fuel directly from the low-pressure outlet 37, it rather being the case that the mixing region 64 is connected between the low-pressure outlet 37 and the MPI port, where the MPI port may be or is supplied with fuel from the mixing region 64.
It is seen particularly clearly from
It may also be seen from
In particular, it is provided that the low-pressure port 39 is supplied with fuel from the mixing region 64. Here, it is conceivable that the low-pressure port 39 is designed to conduct at least a part of the fuel conveyed by means of the low-pressure fuel pump 28 and fed to the high-pressure fuel pump 10 and flowing through the low-pressure outlet 37 away from the high-pressure fuel pump 10, in particular from the pump device 11, to the second injection device 20, such that, for example, at least a part of the fuel flowing through the duct 41 is at least a part of the fuel flowing through the low-pressure outlet 37. Furthermore, in the first embodiment, it is provided that the ducts 32, 41, 68 and 72 are arranged in an at least substantially cross-shaped manner.
The mixing region 64 has at least one first feed opening 76, by means of which the mixing region 64 is fluidically connected to the low-pressure outlet 37 and may thus be supplied with the fuel flowing through the low-pressure outlet 37. Therefore, the duct 68 or the low-pressure port 66 is a return line from the high-pressure fuel pump 10. The mixing region 64 furthermore has a second feed opening 78, by means of which the mixing region 64 is supplied, upstream of the high-pressure fuel pump 10, with fuel from the duct 72 and thus from the low-pressure fuel pump 28 or the tank 26. This means that the above-described fresh fuel may flow via the second feed opening 78 into the mixing region 64, where the fuel flowing through the low-pressure outlet 37 may flow into the mixing region 64 via the first feed opening 76.
The mixing region 64 furthermore comprises a first discharge opening 80, via which the fuel is fed from the mixing region 64 into the low-pressure inlet 31. This means that the mixing region 64 is fluidically connected by means of the first discharge opening 80 to the low-pressure inlet 31. Finally, the mixing region 64 has a second discharge opening 82, by means of which the low-pressure port 39, in particular the duct 41, is fluidically connected to the mixing region 64, such that, for example, fuel is fed from the mixing region 64 via the second discharge opening 82 to the low-pressure port 39, in particular to the duct 41. In the present case, the feed opening 78 and the discharge opening 80 are arranged in respective first planes which run at least substantially parallel to one another. Furthermore, the feed opening 76 and the discharge opening 82 are arranged in respective second planes which run at least substantially parallel to one another and which run at least substantially perpendicular to the first planes.
In the third embodiment, it is provided that the second discharge opening 82 is arranged upstream of the first feed opening 76 in relation to a flow direction of the fuel from the second feed opening 78 to the first discharge opening 80, where the cooling medium is introduced via the first feed opening 76 into the mixing region and the fresh fuel is introduced via the second feed opening 78 into the mixing region 64, and where fuel is fed from the mixing region 64 via the discharge opening 80 to the low-pressure inlet 31 and via the discharge opening 82 to the duct 41 or to the fuel distribution element 24. This means that the MPI port (low-pressure port 39) branches off a short distance upstream of the feed opening 76 that constitutes an inflow for the hot cooling medium into the mixing region 64, such that the hot medium flowing in via the duct 68 and the mixing region 64, in the form of the hot fuel, is not conducted directly to the MPI port or to the fuel distributor 24.
In the first, second and third embodiments, the mixing region 64 has an at least substantially rectangular inner circumference. In the fourth embodiment, it is provided that the mixing region is at least partially, in particular at least predominantly, of spherical or spherical-segment-shaped form on the inner circumference, where the mixing region 64 has a large volume. In particular, in the mixing region 64, an enlarged volume is provided in relation to the ducts 32, 41, 68 and 72. The fuel flowing into the mixing region 64 via the ducts 68 and 72 mixes in particular owing to its respective flow and owing to the shape or inner circumferential shape of the mixing region 64.
The fuel is a fluid, in particular a liquid fluid, where the fuel flowing through the duct 68 constitutes for example a first flow, in particular a first fluid flow, where the fuel flowing through the duct 72 constitutes for example a second flow, in particular a second fluid flow. The fluid flows are introduced into the mixing region 64 or fed to the mixing region 64 via the feed openings 76 and 78, such that the feed openings 76 and 78 constitute inlets of the mixing region 64. The fluid flows may mix in the mixing region 64.
Fluid, that is to say mixed fuel, is discharged from the mixing region 64 via the discharge openings 80 and 82, such that the discharge openings 80 and 82 constitute outlets of the mixing region 64. As an alternative to the spherical form of the mixing region 64 on the inner circumference as shown in
The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2015 219 419.1 | Oct 2015 | DE | national |
This application claims the benefit of PCT Application PCT/EP2016/072245, filed Sep. 20, 2016, which claims priority to German Patent Application 10 2015 219 419.1, filed Oct. 7, 2015. The disclosures of the above applications are incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/EP2016/072245 | Sep 2016 | US |
| Child | 15945115 | US |
