Hydraulic hybrid powertrain with exhaust-heated accumulator

1 . A hydraulic hybrid powertrain, comprising:

an engine;

at least one pump/motor assembly operatively associated with the engine;

an accumulator fluidly coupled to the at least one pump/motor assembly;

a reservoir fluidly coupled to the at least one pump/motor assembly; and

a heat exchanger associated with the accumulator, the heat exchanger being configured to receive exhaust from the engine.

2 . The hydraulic hybrid powertrain of claim 1 , wherein the at least one pump/motor assembly includes two pump/motors.

3 . The hydraulic hybrid powertrain of claim 2 , wherein both pump/motors are fluidly coupled to the accumulator and the reservoir.

4 . The hydraulic hybrid powertrain of claim 1 , further including an exhaust system associated with the engine, the exhaust system being configured to receive exhaust from the engine and direct exhaust to the atmosphere.

5 . The hydraulic hybrid powertrain of claim 1 , further including

a control valve configured to selectively permit exhaust to be directed to the heat exchanger; and

a controller configured to operate the control valve.

6 . The hydraulic hybrid powertrain of claim 5 , further including a cooling component associated with the accumulator.

7 . The hydraulic hybrid powertrain of claim 6 , further including a sensor configured to sense a predetermined parameter associated with the accumulator and deliver a signal to the controller indicative of the predetermined parameter sensed by the sensor, and wherein the controller is configured to operate at least one of the control valve and the cooling component in response to the signal.

8 . The hydraulic hybrid powertrain of claim 7 , wherein the sensor is configured to sense at least one of a volume, a temperature, a pressure, and a viscosity of a fluid associated with an accumulator.

9 . The hydraulic hybrid powertrain of claim 5 , wherein the controller is configured to alternately and selectively operate the control valve to direct exhaust to the heat exchanger and operate a cooling component to extract heat from the heat exchanger.

10 . A method of recovering energy in a hydraulic hybrid powertrain, comprising:

operating an engine and an associated pump/motor assembly;

alternately directing fluid between a reservoir and an accumulator with the pump/motor assembly; and

heating the fluid in the accumulator by directing exhaust from the engine to a heat exchanger associated with the accumulator.

11 . The method of claim 10 , further including

associating a cooling component with the heat exchanger; and

selectively operating the cooling component to cool the heat exchanger.

12 . The method of claim 11 , further including

sensing a predetermined parameter associated with the heat exchanger; and

selectively directing exhaust to the heat exchanger in response to the sensed predetermined parameter.

13 . The method of claim 11 , further including

sensing a predetermined parameter associated with the heat exchanger; and

alternately directing exhaust to the heat exchanger and operating the cooling component in response to the sensed predetermined parameter.

14 . A machine, comprising:

an engine;

at least one pump/motor assembly operatively connected to the engine;

an accumulator fluidly coupled to the at least one pump/motor assembly;

a reservoir fluidly coupled to the at least one pump/motor assembly;

a heat exchanger associated with the accumulator, the heat exchanger being configured to partially receive exhaust from the engine; and

an output component operatively associated with at least one of the engine and the at least one pump/motor assembly.

15 . The machine of claim 14 , wherein the at least one pump/motor assembly includes two pump/motors.

16 . The machine of claim 15 , wherein both pump/motors are fluidly coupled to the accumulator and the reservoir.

17 . The machine of claim 14 , further including an exhaust system associated with the engine, the exhaust system being configured to receive exhaust from the engine and direct exhaust to the atmosphere.

18 . The machine of claim 14 , further including

a control valve configured to selectively direct exhaust to the heat exchanger;

a cooling component associated with the accumulator;

a sensor configured to sense a predetermined parameter associated with the accumulator; and

a controller configured to operate the control valve and the cooling component.

19 . The machine of claim 18 , wherein the controller is configured to alternately operate the control valve to direct exhaust to the heat exchanger and operate the cooling component to extract heat from the heat exchanger in response to the predetermined parameter associated with the accumulator sensed by the sensor.

20 . The machine of claim 18 , wherein the sensor is configured to sense at least one of a volume, a temperature, a pressure, and a viscosity of a fluid associated with the accumulator.