Cooling system after engine shut-down, cylinder head, and method for operating a cooling system after engine shut-down

Abstract

A cooling system after engine shut-down includes a pump, a coolant duct for a coolant, and at least one component to be cooled. The coolant duct is associated with a fuel pump. A cylinder head for an internal combustion engine and a method for operating the cooling system after engine shut-down are provided.

Claims

1. A cooling system after engine shut-down, comprising: a pump; at least one component to be cooled; and a coolant duct for a coolant and the at least one component to be cooled, wherein the coolant duct is assigned to a fuel pump; wherein the at least one component to be cooled is a cylinder head, wherein the fuel pump is fastened to the cylinder head by a holding fixture, and wherein the coolant duct extends through the holding fixture.

2. The cooling system after engine shut-down as claimed in claim 1, wherein another component to be cooled is an exhaust gas turbocharger.

3. The cooling system after engine shut-down as claimed in claim 1, further comprising: a coolant cooler provided in the cooling system after engine shut-down at least piecewise parallel to or in series with the coolant duct.

4. The cooling system after engine shut-down as claimed in claim 3, further comprising: a fan assigned to the cooling system after engine shut-down.

5. The cooling system after engine shut-down as claimed in claim 1, further comprising: a fan assigned to the cooling system after engine shut-down.

6. A cylinder head for an internal combustion engine, through which a part of the coolant duct of a cooling system after engine shut-down as claimed in claim 1 extends.

7. A method for operating a cooling system after engine shut-down comprising a pump and a coolant duct extending through a holding fixture for a coolant and at least one component to be cooled, wherein the at least one component to be cooled is a cylinder head and a fuel pump is fastened to the cylinder head by the holding fixture, the method comprising the an act of: controlling an operation of the pump of the cooling system after engine shut-down occurs.

8. The method as claimed in claim 7, wherein the act of controlling the operation of the pump is based on a known variable of an engine control unit.

9. The method as claimed in claim 8, wherein the known variable is a minimum cooling requirement of the at least one component to be cooled and of the fuel pump.

10. The method as claimed in claim 7, wherein the cooling system after engine shut-down further comprises a fan and the method further comprising the act of operating the fan based on, a determined demand-based control.

11. The method as claimed in claim 10, wherein the determined demand-based control is based on a known variable of an engine control unit.

12. The method as claimed in claim 11, wherein the known variable is a minimum cooling requirement of the at least one component to be cooled and of the fuel pump.

13. The method as claimed in claim 7, further comprising the act of: switching at least one switchable actuator assigned to the cooling system after engine shut-down during operation of the cooling system after engine shut-down so as to adapt a cooling effect for the at least one component to be cooled and/or the fuel pump.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a perspective view of an internal combustion engine with a cooling system after engine shut-down according to an embodiment of the invention.

(2) FIG. 2 is a cross-sectional representation of a part of the internal combustion engine from FIG. 1.

(3) FIG. 3 is a schematic overview of a cooling system after engine shut-down according to an embodiment of the invention in the case of an internal combustion engine according to a first embodiment.

(4) FIG. 4 is a schematic overview of a cooling system after engine shut-down according to an embodiment of the invention in the case of an internal combustion engine according to a second embodiment.

DETAILED DESCRIPTION OF THE DRAWINGS

(5) FIG. 1 shows an internal combustion engine 10, which includes an engine block 12 and a cylinder head 14, which is coupled with engine block 12.

(6) Internal combustion engine 10 also includes a fuel pump 16, which in the embodiment shown is fastened to cylinder head 14 by way of a holding fixture 18 in the form of a pump carrier. Fuel pump 16 can be a high-pressure fuel pump. Moreover, internal combustion engine 10 includes an exhaust gas turbocharger 20, which is a component of internal combustion engine 10 that is to be cooled.

(7) Internal combustion engine 10 further includes a cooling system 22 after engine shut-down, with which exhaust gas turbocharger 20 and fuel pump 16, amongst other things, are cooled, as will be explained below.

(8) Cooling system 22 after engine shut-down is in particular constituted such that the components of internal combustion engine 10 to be cooled are still cooled when internal combustion engine 10 is shut down hot.

(9) For this purpose, cooling system 22 after engine shut-down has its own pump 24, which in the embodiment shown is constituted as an electric auxiliary pump (see FIG. 3). Alternatively, a non-electric pump can be provided.

(10) Furthermore, cooling system 22 after engine shut-down comprises a coolant duct 26 for a coolant, which coolant duct extends from pump 24 through cylinder head 14 up to exhaust gas turbocharger 20.

(11) Coolant duct 26 accordingly comprises a coolant feed line 28, which extends from pump 24 into cylinder head 14. Proceeding from coolant feed line 28, coolant duct 26 runs along a region 29 inside cylinder head 14 that is assigned to holding fixture 18 of fuel pump 16. The coolant (K) flowing through coolant duct 26, which is represented by the arrow, reduces the heat (W) transmitted by internal combustion engine 10 to holding fixture 18, which is also represented by corresponding arrows. The heat input of internal combustion engine 10 into holding fixture 18 and fuel pump 16 connected thereto is therefore greatly reduced, for which reason the fuel present in fuel pump 16 is not heated so intensively that it could boil.

(12) After the coolant has flowed through cylinder head 14, the coolant flows into an exhaust gas turbocharger feed line 30, which in the embodiment shown is located at the side of engine block 12 and leads to an entry 32 of exhaust gas turbocharger 20. Exhaust gas turbocharger 20 is therefore cooled by the same coolant that has previously cooled fuel pump 16.

(13) Internal combustion engine 10 also includes a water pump 34, driven mechanically for example.

(14) As a result of provided pump 24, a cooling system after engine shut-down is created which is also still active when internal combustion engine 10 is switched off during a hot shut-down or is still running. Accordingly, the coolant is still conveyed through coolant duct 26 when an internal combustion engine is shut down hot, in order to cool fuel pump 16 and exhaust gas turbocharger 20. In the case of an electric pump as pump 24, the cooling after engine shut-down can accordingly take place independently of the operation of the internal combustion engine.

(15) The coolant used to cool exhaust gas turbocharger 20 is therefore first diverted into cylinder head 14, so that the coolant cools cylinder head 14 or reduces the heat input, particularly into region 29 in which holding fixture 18 with cooling pump 16 is arranged. To this extent, fuel pump 16 and the fuel contained therein is cooled indirectly, which effectively prevents the fuel from evaporating and vapor bubbles from forming, which can lead to poor starting behavior of internal combustion engine 10. After the cooling of fuel pump 16, exhaust gas turbocharger 20 is cooled by the same coolant.

(16) As an alternative to the embodiment shown, wherein coolant duct 26 indirectly cools fuel pump 16, provision can also be made such that fuel pump 16 has in its housing an interface to which coolant duct 26 can be connected, so that coolant duct 26 would run at least partially through fuel pump 16 itself.

(17) Particularly effective cooling of the described components is achieved if, in cooling system 22 after engine shut-down, a coolant cooler 40, for example in the form of an air-coolant heat exchanger, is incorporated in series or at least piecewise parallel to coolant duct 26 and at least a partial volume flow of the coolant flows through said coolant cooler (see FIG. 4).

(18) The additional cooling effect of coolant cooler 40 on the coolant and therefore also on the components to be cooled can be further increased for example by the operation of a, in particular electric, fan 41 after the hot shut-down of internal combustion engine 10. Through the operation of pump 24, at least a partial volume flow of the coolant is pumped through coolant cooler 40, which is additionally cooled by the operation of fan 41 and thus enables more efficient cooling of the components to be cooled, in particular fuel pump 16 and exhaust gas turbocharger 20 and/or cylinder head 14.

(19) The sequence in which the coolant flows through the components to be cooled is represented here only by way of example and can be selected arbitrarily. For example, the flow direction of the coolant represented schematically in FIGS. 2 to 4 with the aid of the arrows can also be reversed into the opposite direction, so that for example, proceeding from pump 24, exhaust gas turbocharger 20 is first cooled and then fuel pump 16.

(20) Since no additional components are required, cooling system 22 after engine shut-down, with which fuel pump 16 and exhaust gas turbocharger 20 are cooled, is constituted in a particularly cost-effective manner, since only components already used, which serve for the cooling after engine shut-down of exhaust gas turbocharger 20, are relied on.

(21) In addition, no additional electronic components are required, since the already provided electronic components of the cooling system after engine shut-down of exhaust gas turbocharger 20 merely have to be adapted.

(22) Moreover, costly ventilation measures in cooling system 22 after engine shut-down can be dispensed with, since fuel pump 16, in the installed state of internal combustion engine 10, lies above the components of cooling system 22 after engine shut-down, as a result of which a siphon formation in cooling system 22 after engine shut-down is prevented.

(23) Furthermore, with cooling system 22 after engine shut-down or cylinder head 14, an additional cooling function is created for thermally highly stressed regions of cylinder head 14, for example exhaust valve crosspieces.

(24) A particularly advantageous implementation according to the invention emerges if the cooling of the components takes place in a demand-based manner. The maximum individual cooling requirement in each case of the respective components to be cooled must be met herein by cooling system 22 after engine shut-down.

(25) Such an individual cooling requirement consists, for example, of a combination of a control duration and a control intensity, e.g. for the variation of the delivered coolant volume flow, of pump 24, of a control duration and control intensity, e.g. for the variation of the speed, of a fan 41, as well as of a control duration and control signal of any further switchable components in cooling system 22 after engine shut-down, for example of an electrically switched actuator 42 (see FIG. 4).

(26) The determination of the individual cooling requirement of a component can take place for example by means of an empirical or physical model, for example in the form of a model of the maximum temperature of the component for the time interval after a possible shut-down of internal combustion engine 10, which is stored in the engine control unit.

(27) For example, the need for and the magnitude of an individual cooling requirement of for example fuel pump 16 or exhaust gas turbocharger 20 can be determined from variables of the current engine operation, e.g. current coolant temperature, current oil temperature, current engine power averaged over a specific period, current ambient temperature etc.

(28) If the need for cooling after engine shut-down of at least one component results therefrom, cooling system 22 after engine shut-down is activated during the shut-down of internal combustion engine 10 and operated in a demand-based manner corresponding to the maximum individual cooling requirement of all the components to be cooled.

(29) The energy consumption required by cooling system 22 after engine shut-down can thus be correspondingly minimized.

(30) A cooling system 22 after engine shut-down and a cylinder head 14 are thus easily created, with which active cooling of fuel pump 16 can be guaranteed in an efficient and cost-effective manner.

(31) The foregoing disclosure has been set forth merely to illustrate the invention and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construed to include everything within the scope of the appended claims and equivalents thereof.