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US 12,092,209 B2Granted
Hydromechanical transmission and control method
AssigneeDana Italia S.R.L.
InventorsLorenzo Dalla Palma, Claudio Angeloni
Life of this patent
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Abstract
Methods and systems for a hydromechanical transmission in a vehicle are provided herein. In one example, the transmission system includes a hydrostatic assembly with a hydraulic pump in fluidic communication with a hydraulic motor. The transmission system further includes a controller configured to selectively transition between a torque control mode and a speed control mode of the hydrostatic assembly while the vehicle is on a slope.
Claims17
A transmission system for a vehicle, comprising:
- a hydrostatic assembly comprising a hydraulic pump in fluidic communication with a hydraulic motor;
- a mechanical assembly rotationally coupled to the hydrostatic assembly;
- and
- a controller including:
- instructions that when executed, while the vehicle is on a slope, cause the controller to:
- selectively transition between a torque control mode and a speed control mode of the hydrostatic assembly;
- wherein the mechanical assembly includes a plurality of clutches;
- wherein, in the torque control mode, the hydraulic pump is operated using a hydraulic motor torque reference;
- wherein, in the speed control mode, the hydraulic pump is operated using a hydraulic motor speed reference;
- wherein the plurality of clutches include a forward drive clutch and a reverse drive clutch;
- wherein selectively transitioning between the torque control mode and the speed control mode includes:
- activating the speed control mode to achieve a vehicle standstill target;
- in the speed control mode, initiating simultaneous engagement of the forward drive clutch and the reverse drive clutch to prevent rotation of an output of the transmission system;
- and
- when the forward drive clutch and the reverse drive clutch are engaged, operating the hydrostatic assembly in the torque control mode and reducing a differential pressure of the hydrostatic assembly.
12 more elements
A control method for a transmission system, comprising:
- selectively transitioning between a torque control mode and a speed control mode of a hydrostatic assembly through operation of a hydraulic pump and a hydraulic motor in the hydrostatic assembly;
- wherein the hydraulic pump is in fluidic communication with the hydraulic motor;
- wherein the transmission system includes:
- a mechanical assembly rotationally coupled to the hydrostatic assembly;
- wherein, in the torque control mode, the hydraulic pump is operated using a hydraulic motor torque reference;
- and
- wherein, in the speed control mode, the hydraulic pump is operated using a hydraulic motor speed reference;
- wherein selectively transitioning between the torque control mode and the speed control mode includes:
- operating the hydrostatic assembly in the speed control mode to achieve vehicle standstill and registering a pre-load pressure that maintains vehicle standstill;
- and
- re-pressurizing the hydraulic pump and the hydraulic motor using the registered pre-load pressure.
8 more elements
A hydromechanical variable transmission system of a vehicle, comprising:
- a hydrostatic assembly including a variable displacement hydrostatic pump and a hydrostatic motor;
- a mechanical assembly rotationally coupled to the hydrostatic assembly;
- and
- a controller including:
- instructions that when executed, while the vehicle is on a slope, cause the controller to:
- coordinate operation of the hydrostatic assembly in a torque control mode and a speed control mode to hold the vehicle in a standstill condition, wherein coordinating operation of the hydrostatic assembly in the torque control mode and the speed control mode includes:
- while a forward drive clutch and a reverse drive clutch in the mechanical assembly are in simultaneous engagement, depressurize the hydrostatic assembly while the hydrostatic assembly is operated in the torque control mode to achieve a null torque set-point.
4 more elements
Dependencies are inferred from the claim text.