Method for controlling engine braking in a vehicle powertrain
AssigneeEaton Corporation
InventorsIan D. McKenzie, Craig S. Jacobs
Life of this patent
Estimating the term…
Abstract
A method is disclosed for controlling engine braking horsepower for a power transmission mechanism in a vehicle powertrain. The transmission mechanism has multiple-ratio gearing and a continuously variable transmission unit arranged in parallel disposition. A target engine speed during an engine braking mode is maintained by controlling the ratio of the continuously variable transmission unit.
Claims3
A method for controlling engine braking in a power transmission mechanism for a vehicle powertrain, the transmission mechanism comprising multiple-ratio gearing, a mixer gear unit connected to a power output element and a continuously variable transmission unit, the multiple-ratio gearing and the continuously variable transmission unit defining parallel driving torque flow paths from an engine, the method comprising:
- establishing an engine braking power delivery path from the power output element to the engine through the multiple-ratio gearing;
- changing the ratio of the continuously variable transmission unit toward an overdrive ratio as each of the ratios of the multiple-ratio gearing is established during engine braking for conditioning the continuously variable transmission unit for effecting optimum engine braking horsepower for a range of vehicle speeds;
- and
- controlling the continuously variable transmission unit ratio to effect and hold a target engine braking speed.
Dependencies are inferred from the claim text.