Coolant circuit for an internal combustion engine

Abstract

A coolant circuit is provided for an internal combustion engine having a compression machine for intake air. The coolant circuit includes a high-temperature circuit and a low temperature circuit. The high-temperature circuit is provided in order to cool the internal combustion engine by way of a coolant radiator and a first coolant pump arranged in the high-temperature circuit. The low-temperature circuit is provided with a second coolant pump in order to cool the intake air compressed by the compression machine by way of an intercooler and in order to cool a coolant of a coolant circuit in a condenser. The high-temperature circuit and the low-temperature circuit are cooling circuits which are separated from each other. The thermal base load of the low-temperature circuit is reduced by this design, whereby the pressure level in the coolant circuit can be reduced resulting positively in a reduction of the energy consumption.

Claims

1. A coolant circuit for an internal combustion engine having a compression machine for intake air, the coolant circuit comprising: a high-temperature circuit; a low-temperature circuit; and a controller, wherein the high-temperature circuit is configured to cool, using a first coolant, the internal combustion engine via a first coolant radiator and a first coolant pump arranged in the high-temperature circuit, the low-temperature circuit comprises: a second coolant pump; a second coolant radiator; a first valve disposed upstream or downstream of an intercooler; and a second valve disposed upstream or downstream of a condenser, wherein the controller is configured to control opening or closing of the first and second valves differently between an idling operation of the engine and a driving operation of the engine to cool, using a second coolant separate from the first coolant, air compressed by the compression machine via the intercooler and to cool, using the second coolant, a refrigerant of a refrigeration cycle in the condenser, and the high-temperature circuit and the low-temperature circuit are cooling circuits that are completely separated from each other.

2. The coolant circuit according to claim 1, wherein the intercooler and the condenser are arranged in parallel to one another in the low-temperature circuit.

3. The coolant circuit according to claim 2, wherein the first valve is arranged upstream of the intercooler relative to a flow direction of the second coolant.

4. The coolant circuit according to claim 3, wherein the second valve is arranged upstream of the condenser relative to a flow direction of the second coolant.

5. The coolant circuit according to claim 4, wherein the first and second valves are controlled based on a demand for air conditioning and/or a load demand on the engine.

6. The coolant circuit according to claim 4, wherein the first and second valves are controlled such that the first valve is closed while the second valve is open during idling of the engine.

7. The coolant circuit according to claim 3, wherein the second coolant pump is configured to operate at a speed tailored to demand.

8. The coolant circuit according to claim 2, wherein the second valve is arranged upstream of the condenser relative to a flow direction of the second coolant.

9. The coolant circuit according to claim 2, wherein the second coolant pump is configured to operate at a speed tailored to demand.

10. The coolant circuit according to claim 2, wherein the second coolant flows through both the intercooler and the condenser.

11. The coolant circuit according to claim 2, wherein the first and second valves are controlled based on a demand for air conditioning and/or a load demand on the engine.

12. The coolant circuit according to claim 1, wherein the first valve is arranged upstream of the intercooler relative to a flow direction of the second coolant.

13. The coolant circuit according to claim 1, wherein the second valve is arranged upstream of the condenser relative to a flow direction of the second coolant.

14. The coolant circuit according to claim 13, wherein the second coolant pump is configured to operate at a speed tailored to demand.

15. The coolant circuit according to claim 1, wherein the second coolant pump is configured to operate at a speed tailored to demand.

16. The coolant circuit according to claim 1, wherein the low-temperature circuit indirectly cools the air compressed by the compression machine using the second coolant.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) FIG. 1 is a block diagram of a cooling circuit according to an embodiment of the invention for an internal combustion engine

DETAILED DESCRIPTION OF THE DRAWING

(2) FIG. 1 shows a block diagram of a cooling circuit according to an embodiment of the invention for an internal combustion engine 1 with a compression machine 2; the present exemplary embodiment shows a compressor of an exhaust turbocharger to compress intake air for the internal combustion engine. It goes without saying that this can also be a mechanical charger.

(3) The entire coolant circuit consists of a high-temperature circuit 3 and a low-temperature circuit 4.

(4) In the high-temperature circuit 3, a coolant radiator 5 is provided to cool the internal combustion engine 1, and a first coolant pump 6 is provided, which is arranged in the high-temperature circuit 3. The intake temperature into the internal combustion engine can be regulated and/or controlled with the help of a thermostatic valve 14. A direction of flow of the coolant is shown schematically in FIG. 1 by way of arrows. Furthermore, a fan 13 is provided to improve the cooling efficiency of the coolant radiator 5.

(5) Furthermore, the low-temperature circuit 4 includes a second coolant pump 7 as well as a second coolant radiator 12 to cool the intake air that has been compressed by the compression machine 2 by way of an intercooler 8. Additionally, the low-temperature circuit 4 includes a condenser 9 to cool a refrigerant of a refrigeration cycle for air conditioning of the passenger compartment.

(6) According to the invention, the high-temperature circuit 3 and the low-temperature circuit 4 are separate circuits. Furthermore, the intercooler 8 and the condenser 9 are arranged in parallel to one another in the low-temperature circuit 4, e.g. the coolant flows through both of them in parallel. In the present embodiment, a first valve 10 is provided in the low-temperature circuit 4 upstream of the intercooler 8 in the direction of flow of the coolant, and a second valve 11 is provided upstream of the condenser 9. In a further embodiment, the valves 10 and 11 may also be arranged downstream of the condenser 9 or the intercooler 8, or they may be arranged in an intermixed order. Preferably, the valves 10 and 11 can be operated in a regulated or controlled manner by an electronic control unit (not shown), such as a motor control device, for example.

(7) Furthermore, the speed of second coolant pump 7 can also be operated via the electronic control unit according to the demand on the system, which means that a high cooling demand sets a high speed and a low cooling demand sets a low speed for the second coolant pump 7. The second coolant pump 7 could be an electrically operated coolant pump, for example.

(8) In the present embodiment, the second coolant radiator 12 is arranged upstream of the coolant radiator 5 with respect to the air flow direction, which is represented schematically by three wide arrows In other embodiments, the coolant radiators may also be arranged to partially overlap, or to be arranged side by side.

(9) With the coolant circuit according to the invention for an internal combustion engine 1, the following operating situations can then be advantageously represented as a function of the operating condition of the internal combustion engine 1:

(10) TABLE-US-00002 Operating Second point coolant First Second of the ICE: pump: valve: valve: Comment: e.g.: at idle Controlled closed open High demand for air by conditioning at idle, for demand example during stop-and-go traffic at high outside air temperature. In this case, increase of the coolant flow over the condenser, and reduction of the cooling of the charge air, or valve timing, if applicable. e.g.: Max. Controlled open closed High demand on charge air power on a by cooling with simultaneously restricted demand low air conditioning demand, access such as during moderate highway outside temperatures and high [Autobahn] demand driving (e.g. restricted access highway, dynamic mountain driving) Max. air Controlled open open High demand driving resulting conditioning by in high cooling demand of the and max. demand intercooler. power of Simultaneously high internal outside air temperature and combustion high air conditioning engine demand.

(11) Due to the design of the cooling circuit according to the invention, parasitic heat intake is reduced, and therefore the thermal base load of the low-temperature cooling circuit is reduced. This leads to a reduction of the pressure level in the refrigeration cycle, which results in a positive reduction of the total energy consumption.

LIST OF REFERENCE SYMBOLS

(12) 1. Internal combustion engine 2. Compression machine 3. High-temperature circuit 4. Low-temperature circuit 5. Coolant radiator 6. First coolant pump 7. Second coolant pump 8. Intercooler 9. Condenser 10. First valve 11. Second valve 12. Second coolant radiator 13. Fan 14. Thermostatic valve

(13) 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.