Engine autostop control
AssigneeToyota Motor Engineering & Manufacturing North America, Inc.
InventorThomas S. Hawley
Life of this patent
Estimating the term…
Abstract
Systems and methods are provided for determining an optimal point during operation of a hybrid electric vehicle towing a trailer at which the energy that can be recouped through regenerative braking is maximized. Operating conditions or characteristics of the hybrid electric vehicle and the brake characteristics of the trailer are considered in determining the optimal point at which the energy that can be recouped is maximized. At the optimal point at which the energy that can be recouped is maximized, the engine of the hybrid electric vehicle is turned off. Otherwise, the engine of the hybrid electric vehicle is left on.
Claims18
A method of operating a hybrid electric vehicle towing a trailer, comprising:
- calculating mass and road load of the vehicle and the trailer being towed by the vehicle;
- calculating force absorbed by brakes of the trailer;
- generating a driver braking profile and determining anticipated deceleration given a vehicle speed based on the driver braking profile;
- calculating potential energy that can be recouped based on the anticipated deceleration relative to the calculated mass and road load of the vehicle and trailer and the force absorbed by the brakes of the trailer;
- determining an amount of regenerative braking available for the vehicle based on the calculated potential energy that can be recouped;
- determining a vehicle speed at which an engine of the vehicle should be stopped based on the amount of regenerative braking available;
- stopping an engine of the vehicle at the determined vehicle speed;
- and
- performing regenerative braking upon the vehicle reaching the vehicle speed at which the engine of the vehicle is to be stopped.
A hybrid electric vehicle towing a trailer, comprising:
- an internal combustion engine;
- an electric motor operatively connected in parallel to the internal combustion engine;
- and
- an electronic control unit adapted to control operation of the internal combustion engine in accordance with one or more control signals from an engine autostop control circuit instructing the electronic control unit to turn the internal combustion engine off upon the hybrid electric vehicle reaching a threshold vehicle speed at which the electric motor can recoup all available energy through regenerative braking and the hybrid electric vehicle is decelerating.
A method comprising:
- calculating mass and road load of a vehicle and trailer being towed by the vehicle;
- calculating force absorbed by brakes of the trailer;
- generating a driver braking profile and determining anticipated deceleration given a vehicle speed based on the driver braking profile;
- calculating potential energy that can be recouped based on the anticipated deceleration relative to the calculated mass and road load of the vehicle and trailer and the force absorbed by the brakes of the trailer;
- determining a current speed at which the vehicle is traveling, determining a current requested brake force, determining a trailer brake gain based on the force absorbed by the brakes of the trailer, and determining a remaining capacity of a power storage device of the vehicle;
- comparing the current speed at which the vehicle is traveling, the current requested brake force compensated by the trailer brake gain, and the remaining capacity of the power storage device of the vehicle to the anticipated deceleration and potential energy that can be recouped based on the anticipated deceleration;
- determining a vehicle speed at which an engine of the vehicle is to be stopped;
- and
- performing regenerative braking upon the vehicle reaching the vehicle speed at which the engine of the vehicle is to be stopped.
Dependencies are inferred from the claim text.