Method and system for compressed air supply
Methods and systems to provide compressed air to one or more air consumers external to the engine using transmission fluid from a transmission pump are presented. In one example, the transmission fluid may be routed to drive an air compression system including two cylinders. The air compressed at the compression system may be stored in a tank and/or provided to the one or more air consumers.
1 . A method for a vehicle, the method comprising:
supplying transmission fluid from a transmission pump of a transmission system to drive an air compression system and to lubricate hydraulically actuated components of a transmission of the transmission system, wherein the transmission pump is configured to be driven by an engine of the vehicle, and
providing compressed air from the air compression system to one or more air consumers external to the engine of the vehicle via a pressure regulator, wherein the air compression system includes a first cylinder and a second cylinder, wherein the transmission pump is coupled to the first cylinder via a control valve, wherein supplying transmission fluid from the transmission pump to drive the air compression system includes cycling a position of the control valve between a first position fluidically coupling a first side of the first cylinder to a transmission fluid outlet of the transmission pump, and a second position fluidically coupling a second side of the first cylinder to the transmission fluid outlet of the transmission pump, wherein the control valve is held at the first position for a threshold duration before it is actuated to the second position, and wherein the control valve is held at the second position for the threshold duration before it is actuated to the first position, and
wherein supplying transmission fluid from the transmission pump to drive the air compression system takes place when the vehicle is stationary with the transmission in park.
2 . The method of claim 1 , wherein the first cylinder houses a first piston and the second cylinder houses a second piston, the first piston operatively connected to the second piston.
3 . The method of claim 2 , wherein only transmission fluid may enter the first cylinder and only air may enter the second cylinder.
4 . The method of claim 3 , wherein the threshold duration is 1-10 seconds.
5 . The method of claim 4 , wherein when the control valve is in the first position, the second side of the first cylinder is fluidically coupled to a return port of the transmission pump, and wherein when the control valve is in the second position, the first side of the first cylinder is fluidically coupled to the return port of the transmission pump.
6 . The method of claim 4 , wherein cycling the control valve includes supplying transmission fluid and removing transmission fluid alternately to and from each of the first side and the second side of the first cylinder.
7 . The method of claim 4 , wherein the first piston oscillates within the first cylinder during the cycling of the control valve, the first piston driving the second piston to oscillate within the second cylinder.
8 . The method of claim 7 , further comprising, during oscillation of the second piston within the second cylinder, drawing in ambient air to the second cylinder via two air inlets and compressing the ambient air in the second cylinder, wherein drawing in the ambient air to the second cylinder via the two air inlets comprises drawing in the ambient air to a first chamber of the second cylinder from a first air inlet external to the second cylinder, and to a second chamber of the second cylinder from a second air inlet external to the second cylinder, the first chamber and the second chamber separated by the second piston.
9 . The method of claim 2 , wherein the transmission fluid is supplied to the air compression system in response to a pressure of compressed air stored in an air tank directly fluidically coupled to each of two chambers of the second cylinder separated from one another by the second piston being lower than a first threshold pressure during a request for compressed air at the one or more air consumers.
10 . The method of claim 9 , wherein providing the compressed air includes routing the compressed air from each of the two chambers of the second cylinder to the air tank and the one or more air consumers until the pressure in the air tank increases to a second threshold pressure, the second threshold pressure higher than the first threshold pressure.
11 . The method of claim 10 , further comprising, in response to the pressure of compressed air stored in the air tank increasing to the second threshold pressure, suspending cycling of the control valve to suspend a flow of the transmission fluid from the transmission pump to the air compression system.
12 . The method of claim 1 , further comprising, during supplying transmission fluid from the transmission pump to drive the air compression system, disabling a shift of a gear of the transmission from park and increasing an idling speed of the engine.
13 . A method for a vehicle, the method comprising:
in response to a request for compressed air received via a human-machine interface of the vehicle,
adjusting an operation of an engine of the vehicle and/or an operation of a transmission system of the vehicle, wherein the transmission system is configured to supply transmission fluid to both lubricate hydraulically actuated components of a transmission of the transmission system and drive an air compression system, wherein the operation of the engine and/or the operation of the transmission system is adjusted by:
increasing an idling speed of the engine of the vehicle from a first idling speed to a second idling speed,
monitoring a temperature and pressure of the transmission fluid via respective temperature and pressure sensors coupled to a transmission fluid circuit of the transmission system,
adjusting an operation of a transmission pump of the transmission system in response to the temperature of the transmission fluid increasing above a threshold temperature or the pressure of the transmission fluid increasing above a first threshold pressure by one or more of: reducing a speed of operation of the transmission pump and suspending cycling of a control valve coupling the transmission pump to a first cylinder of the air compression system, and
circulating the transmission fluid through a heat exchanger disposed in the transmission fluid circuit in response to the temperature of the transmission fluid exceeding the threshold temperature;
circulating the transmission fluid through the first cylinder of the air compression system by cycling a position of the control valve between a first position and a second position, wherein the control valve is held at the first position for a threshold duration before it is actuated to the second position, and wherein the control valve is held at the second position for the threshold duration before it is actuated to the first position, wherein the threshold duration is 1-10 seconds;
compressing ambient air in a second cylinder coupled to the first cylinder via a piston within the second cylinder; and
storing the compressed air in an air tank fluidically coupled directly to each of a first chamber and a second chamber of the second cylinder, the first chamber separated from the second chamber by the piston, wherein supplying transmission fluid from the transmission pump to drive the air compression system takes place when the vehicle is stationary with the transmission in park.
14 . The method of claim 13 , wherein the request for compressed air received via the human-machine interface of the vehicle is made when an air pressure in the air tank is lower than a second threshold pressure while a request for operation of an external tool is received from an operator.
15 . The method of claim 13 , wherein the heat exchanger is configured to transfer heat from the transmission fluid to one or more of ambient air or engine coolant.
16 . The method of claim 15 , wherein cycling the control valve oscillates the piston within the second cylinder, draws in ambient air to the second cylinder, and then compresses the ambient air within the second cylinder.
17 . A system for a vehicle, the system comprising:
a transmission pump coupled to a transmission fluid outlet port and a return port, wherein the transmission pump is configured to supply transmission fluid to both lubricate hydraulically actuated components of a transmission and drive an air compression system, wherein the transmission pump is driven by an engine of the vehicle;
a heat exchanger disposed in a transmission fluid circuit, the heat exchanger configured to transfer heat from the transmission fluid to one or more of ambient air or engine coolant;
a control valve coupling each of the transmission fluid outlet port and the return port to a first cylinder of the air compression system;
a first piston housed within the first cylinder, wherein only transmission fluid may enter the first cylinder;
a second cylinder including a second piston coupled to the first piston via a shaft, wherein a first side of the second cylinder is coupled to a first air inlet external to the second cylinder and a second side of the second cylinder is coupled to a second air inlet external to the second cylinder, wherein only air may enter the second cylinder, and wherein during oscillation of the second piston within the second cylinder, ambient air is drawn in alternately via the first air inlet to a first side of the second cylinder and via the second air inlet to a second side of the second cylinder, the first side of the second cylinder separated from the second side of the second cylinder by the second piston;
a pressure sensor coupled to the transmission fluid circuit, wherein the pressure sensor measures the pressure of the transmission fluid in the transmission fluid circuit,
a temperature sensor coupled to the transmission fluid circuit, wherein the temperature sensor measures the temperature of the transmission fluid in the transmission fluid circuit,
an air tank configured to receive and store compressed air from each of the first side and the second side of the second cylinde; and
a pressure regulator fluidically coupled between the air tank and an external tool, the external tool coupled to the air tank via the pressure regulator and a tool trigger valve, the external tool operable using compressed air from the air tank, wherein the transmission pump is configured to supply the transmission fluid to drive the air compression system when the vehicle is stationary with the transmission in park.
18 . The system of claim 17 , further comprising a controller including executable instructions stored in non-transitory memory to: cycle the control valve between a first position and a second position to oscillate the first piston within the first cylinder and the second piston within the second cylinder.
19 . The system of claim 18 , wherein the controller includes further instructions to: draw in ambient air to the first side of the second cylinder via the first air inlet external to the second cylinder and the second side of the second cylinder via the second air inlet external to the second cylinder alternately, compress the ambient air in the first side and the second side of the second cylinder, and supply the compressed air to the air tank or the external tool from the first side and the second side of the second cylinder.