Brake cooling fluid diverter for an off-highway machine

#This patent disclosure relates generally to a brake cooling system and, more particularly, to brake cooling fluid systems and methods to control brake cooling fluid systems.

#Braking systems are used in a large variety of machines and vehicles to control, slow and stop the machine. Exemplary machines include passenger vehicles, trains, dump trucks, and mining vehicles. Moreover, machines increasingly use electric drive systems to provide propulsion. For example, passenger vehicles may use a hybrid drive system whereby a traditional internal combustion engine and an electric motor are used to provide propulsion for the vehicle. Machines, such as a railway engines and off-road vehicles may use a diesel powered engine to drive a generator, which provides electric power to a motor. The motor then provides propulsion for the machine.

#Braking systems may take advantage of components in electric drive systems to provide braking for machines. For example, a hybrid passenger vehicle may include a regenerative braking system whereby the vehicle is slowed by the electric drive system while at the same time a battery in the vehicle is recharged and railway engines may use dynamic retarding to slow the train. Although brake systems utilizing electric drive systems have been used, these systems cannot stop a machine traveling at high speed quickly, nor can these systems consistently slow a heavily loaded machine traveling downhill or in slippery conditions.

#FIG. 1 is a schematic view of an electric drive system including an electric retarding system for a machine.

#FIG. 2 is a logical block diagram illustrating a braking system for a machine including hydraulic friction brakes, a brake oil cooling system and an electric retarder.

#FIG. 3 is a flow chart illustrating one embodiment of a braking control process for a machine including hydraulic friction brakes and an electric retarder.

#Referring now to the drawings, FIG. 1 illustrates a schematic view of an exemplary electric drive system including an electric retarding system for a machine. The exemplary electric drive system includes an engine 100. Suitable engines include gasoline powered and diesel powered internal combustion engines. When in a drive configuration, the engine 100 powers a generator 102. The generator 102 produces three-phase alternating current. The three-phase alternating current passes through a rectifier 104, which converts the alternating current to direct current. An inverter or invertors 106 convert the direct current to variable frequency back to alternating current which feeds a motor 108. By controlling the frequency of the current produced by the invertors 106, the speed of the motor 108 is controlled. The motor 108 produces torque which powers the drive wheels 110.

#In an alternative embodiment, an engine is not needed and the motor 108 is driven directly from an electric power source, such as a battery. In some embodiments, one motor powers all drive wheels. In alternative embodiments, various numbers of motors are used to power drive wheels. For example, each drive wheel may have an individual motor associated with the wheel.

#When operating in an electric braking, also known as electric retarding, configuration, the drive wheels 110 power the motor 108. Driving the motor 108 places a torque on the drive wheels 110 and causes them to slow, thus braking the machine. The motor 108 generates alternating current. The inverters 106 convert the alternating current to direct current and feed the current to a chopper 112, which acts as a direct current to direct current convert, and resistor grid 114. The power generated by the motors 108 is thus dissipated as heat by the resistor grid 114. However, in alternative embodiments, the power generated by the motors 108 may be stored for later use. In one embodiment, the power generated by the motors 108 is stored in an electric battery. The energy in the electric battery can then be used in drive mode to power the motors 108 and propel the machine.