Patent Application
20220243641
The present application relates generally to vehicle thermal systems and, more particularly, to a vehicle thermal system having an auxiliary coolant pump with bypass.
Conventional vehicles typically include an engine mounted coolant pump to circulate hot coolant from the engine through the heater core to defrost the windshield and heat the cabin. Some vehicles include an automatic stop/start function to reduce fuel consumption when the vehicle is stopped. However, the automatic stop feature is potentially overridden when the cabin is cold and occupants require heat. Thus, the engine continues to run and fuel consumed in order to heat the cabin. Other pumps have been utilized to maintain coolant flow during engine off, but must be run during engine on to prevent becoming a restriction in the circuit, thus consuming electrical power. Accordingly, while such conventional cooling systems work for their intended purpose, it is desirable to provide improvement in the relevant art.
According to one example aspect of the invention, an auxiliary coolant pump for circulating a coolant in a vehicle thermal system having a main coolant pump is provided. In one exemplary implementation, the auxiliary coolant pump includes a housing, an impeller, a motor selectively driving the impeller, a coolant inlet configured to receive the coolant, a coolant outlet fluidly coupled to the coolant inlet, and a bypass passage fluidly coupled between the coolant inlet and the coolant outlet. When the main coolant pump is on, the auxiliary coolant pump is selectively turned off such that coolant flows through the bypass passage to reduce or eliminate restriction of the coolant flow rate in the thermal system. When the main coolant pump is off, the auxiliary coolant pump is selectively turned on such that coolant continues to flow through at least a portion of the thermal system.
In addition to the foregoing, the described auxiliary coolant pump may include one or more of the following features: wherein the bypass passage is integral with the housing; a valve disposed within the bypass passage to facilitate preventing fluid flow from the coolant outlet to the coolant inlet, and allowing fluid flow from the coolant inlet to the coolant outlet; wherein the valve includes a check ball and valve seat; wherein the valve is a flapper valve; a controller configured to selectively operate the motor to drive the impeller, wherein the controller is configured to operate the motor when an engine of the vehicle is off and the vehicle thermal system demands vehicle cabin heating; and a controller configured to selectively operate the motor to drive the impeller, wherein the controller is configured to operate the motor during a cold start when coolant flow stagnation is desired in an engine of the vehicle for rapid heating thereof.
According to another example aspect of the invention, a thermal system for a vehicle is provided. In one exemplary implementation, the thermal system includes a coolant circuit configured to thermally couple to a vehicle engine for cooling thereof, a main coolant pump configured to circulate coolant through the coolant circuit, a heat exchanger thermally coupled to the coolant circuit, and an auxiliary coolant pump. The auxiliary coolant pump includes an impeller configured to circulate coolant through the coolant circuit, and a housing defining a coolant inlet, a coolant outlet, and a bypass passage fluidly coupled between the inlet and the outlet. When the main coolant pump is on, the auxiliary coolant pump is selectively turned off such that coolant flows through the bypass passage to reduce or eliminate restriction of the coolant flow rate in the coolant circuit. When the main coolant pump is off, the auxiliary coolant pump is selectively turned on to continue to provide coolant flow to the heat exchanger.
In addition to the foregoing, the described thermal system may include one or more of the following features: a valve disposed within the bypass passage to facilitate preventing fluid flow from the coolant outlet to the coolant inlet; wherein the valve allows fluid flow from the coolant inlet to the coolant outlet; wherein the heat exchanger is a cabin heat exchanger configured to provide heating to a cabin of the vehicle, wherein the main coolant pump is turned off and the auxiliary coolant pump is turned on when the vehicle engine is stopped during a stop/start mode; and wherein the heat exchanger is configured to provide heating to a component of the thermal system, wherein the main coolant pump is turned off during a cold start to provide coolant flow stagnation in the vehicle engine for rapid heating thereof, and the auxiliary coolant pump is turned on to continue to provide coolant flow to the heat exchanger.
In addition to the foregoing, the described thermal system may include one or more of the following features: wherein the coolant circuit is a high temperature circuit having a first branch conduit and a second branch conduit; a high temperature radiator thermally coupled to the first branch conduit; wherein the heat exchanger is a cabin heat exchanger thermally coupled to the second branch conduit; a thermostat coupled to the high temperature circuit and configured to receive coolant flow from the engine; wherein the first branch conduit is fluidly coupled between the thermostat and the main coolant pump; and wherein the second branch conduit is fluidly coupled between the thermostat and the main coolant pump.
Further areas of applicability of the teachings of the present disclosure will become apparent from the detailed description, claims and the drawings provided hereinafter, wherein like reference numerals refer to like features throughout the several views of the drawings. It should be understood that the detailed description, including disclosed embodiments and drawings references therein, are merely exemplary in nature intended for purposes of illustration only and are not intended to limit the scope of the present disclosure, its application or uses. Thus, variations that do not depart from the gist of the present disclosure are intended to be within the scope of the present disclosure.
Described herein is a vehicle thermal system with an auxiliary coolant pump having an integrated bypass. The auxiliary coolant pump is disposed between the heater core and the engine and is configured to selectively circulate hot coolant from the engine and maintain cabin comfort and defrost safety even with the engine shut off. The system is configured to operate the auxiliary coolant pump only when the engine and/or main coolant pump is off and allows coolant flow from the main pump to pass through the bypass when the engine is running without restricting the heater core coolant flow rate.
With initial reference to
In the example embodiment, the first branch conduit 32 directs heated coolant to the high temperature radiator 24, where the heated coolant is cooled by ambient air and/or an airflow created by a fan 36. The coolant is then directed to the main coolant pump 28 via a first coolant return line 38. The second branch conduit 34 directs the heated coolant to the auxiliary coolant pump 30 and subsequently to the cabin heat exchanger 26 where thermal energy of the heated coolant is used to provide heating to the vehicle passenger cabin (not shown). The cooled coolant is then directed to the main coolant pump 28 via a second coolant return line 40.
The main coolant pump 28 is disposed within the high temperature circuit 20 and is configured to receive coolant from the first and second coolant return lines 38, 40. When operating, the main coolant pump 28 is configured to circulate the coolant around the high temperature circuit 20. In the example embodiment, the coolant may be selectively supplied to branch conduits 32 and/or 34 such that each of the branch conduits may be used alone or in combination. As such, main coolant pump 28 supplies the cooled coolant to the engine 12 to provide cooling thereto.
With additional reference to
In the example embodiment, the pump housing 50 defines a coolant inlet 58 fluidly coupled to a coolant outlet 60, which are configured to couple to hoses, conduits, etc. of the second branch conduit 34. Advantageously, the auxiliary coolant pump housing 50 includes a bypass passage 62 fluidly coupled between the coolant inlet 58 and the coolant outlet 60. A valve 64 is disposed within bypass passage 62 and is configured to allow bypass flow from the coolant inlet 58 to the coolant outlet 60, but prevent reverse flow from the coolant outlet 60 to the coolant inlet. In the illustrated example, valve 64 is a check valve with a check ball 66 configured to selectively seat within a valve seat 68. However, it will be appreciated that valve 64 may be any suitable valve that enables auxiliary coolant pump 30 to function as described herein such as, for example, a flapper valve.
With continued reference to
Further, it will be appreciated that auxiliary coolant pump 30 is not limited to use in the high temperature circuit 20 and may be utilized in various other thermal systems or vehicle systems. For example, in one additional or alternative implementation, it may be desirable to reduce fuel consumption following a cold start by keeping coolant flow stagnant in the cylinder block and head of the engine 12 for a predetermined time (e.g., 1-2 minutes). This facilitates quicker warm-up of the metal and helps to reduce engine friction and fuel consumption. Some of these engines may be equipped with EGR cooler and/or engine oil heat exchangers (not shown). In the case where it is desirable to provide coolant flow in the EGR cooler and/or engine oil heat exchanger following the cold start, one of auxiliary coolant pumps 30 may be provided in the coolant circuit thereof to provide coolant flow only in this portion of the cooling circuit in the brief period after the cold start.
Once the engine 12 has passed through the coolant stagnation period, the main coolant pump 28 is activated and coolant flow is established throughout the entire high temperature circuit 20, including the second branch conduit 34 with the auxiliary coolant pump 30. In this mode of operation, the auxiliary coolant pump 30 would typically act as a restriction to the intended coolant flow unless the auxiliary coolant pump 30 was powered. However, the bypass passage 62 enables the auxiliary coolant pump 30 to be turned off when the main coolant pump 28 is operational, thereby reducing energy consumption.
In another additional or alternative implementation, it may be desirable to utilize auxiliary coolant pump 30 for cooling turbocharger (not shown) after the engine 12 is shut off. For example, when a very hot engine is shut off (e.g., after towing a trailer), the turbocharger potentially requires coolant flow to avoid overheating during a predetermined time (e.g., 1-2 minutes) after shut off. In such an example, the vehicle continues to operate the auxiliary coolant pump 30 to provide coolant flow to the turbocharger.
Described herein are system and methods for providing additional functionality to vehicle thermal systems by utilizing an auxiliary coolant pump with an integrated bypass. During engine stop/start mode, when cabin heating is required, the engine can be shut off and coolant can still be circulated with the auxiliary coolant pump. Additionally, during engine cold start mode, with coolant stagnation in the engine for rapid warming, the auxiliary coolant pump can be operated to sustain any thermal system components which require constant coolant flow rate even while the cylinder block and head have no flow. In other modes, the auxiliary coolant pump is deactivated, and coolant flow is allowed through the integrated bypass to avoid any unnecessary circuit pressure loss or electrical power consumption.
It will be understood that the mixing and matching of features, elements, methodologies, systems and/or functions between various examples may be expressly contemplated herein so that one skilled in the art will appreciate from the present teachings that features, elements, systems and/or functions of one example may be incorporated into another example as appropriate, unless described otherwise above. It will also be understood that the description, including disclosed examples and drawings, is merely exemplary in nature intended for purposes of illustration only and is not intended to limit the scope of the present disclosure, its application or uses. Thus, variations that do not depart from the gist of the present disclosure are intended to be within the scope of the present disclosure.
