Method and system for controlling cooling fans in a vehicle

1. Technical Field

The embodiments of the invention described herein generally relate to cooling systems for use in a vehicle.

2. Background Art

In conventional vehicles, cooling fans are generally used to cool an engine. With Hybrid Electrical Vehicles (HEV) or fuel cell based vehicles, additional subsystems packaged in the engine compartment or elsewhere in the vehicle may benefit from being cooled to increase subsystem life span and to ensure optimal performance. Such subsystems may include various electrical based motors and power electronics associated with driving the motors.

Accordingly, it would be desirable to provide a system and method for controlling fan speed for a cooling fan to cool a number of subsystems in an HEV or fuel cell based vehicle.

A system and method is disclosed for cooling a control system in a vehicle. In one embodiment, the system comprises vehicle subsystems and a vehicle controller.

The vehicle subsystems are configured to generate a plurality of subsystem temperature signals that are indicative of a measured temperature for each vehicle subsystem. The vehicle controller is configured to generate a desired fan speed signal for each vehicle subsystem in response to each subsystem temperature signal and to compare each desired fan speed signal to each other to determine a maximum desired fan speed signal. The vehicle controller controls the fan such that the fan reaches a speed that is equal to or greater than the maximum desired fan speed signal.

FIG. 1 illustrates diagrammatically an overall vehicle system 100 in accordance to one embodiment of the present invention. The system 100 relates to electric vehicles, and more particularly, to Hybrid Electric Vehicles (HEV). FIG. 1, which generally illustrates one implementation of the system, is provided for exemplary purposes. The system 100 comprises a vehicle system controller (VSC) 102, a vehicle control system (or control system) 104 and a cooling system 106. The vehicle control system 104 is adapted to provide a plurality of temperature signals to the VSC 102. The VSC 102 is configured to control the cooling system 106 to cool the control system 104 in response to the temperature signals. The VSC 102 may be implemented as a stand-alone controller or may be integrated into one or more controllers in the control system 104.

The control system 104 generally comprises a number of subsystems. Such subsystems include an engine subsystem 107, a transmission subsystem 109, a starter-generator subsystem 111, a DC/DC converter 114 and a motor system 115. The engine subsystem 107 comprises an engine 108 and an engine controller 116. The engine 108 is generally referred to as a power generating device that may be used to power the vehicle by consuming fuel. The engine 108, for example, may be any internal combustion engine using a hydrocarbon based fuel, including but not limited to gasoline, diesel, hydrogen, methanol, natural gas, ethanol or other gas or liquid fueled internal combustion engine. Alternatively, the power generating device can be a fuel cell engine, such as a hydrogen-powered fuel cell engine. The engine controller 116 is adapted to control the operation of the engine 108.

A multiplexed data bus 118 is coupled to the VSC 102 and the engine controller 116 to facilitate data communication therebetween. In one example, the multiplexed data bus 118 may be implemented as a part of a high speed controller area network (CAN). In another example, the multiplexed data bus 118 may be implemented as a part of a local interconnect network (LIN). The particular type of multiplexed bus used in the system 100 may be one of various types to meet the desired criteria of a particular implementation.