Patent ID: 7131708

Claim:
Method for coordinating regenerative and engine retard braking of a vehicle comprising a hybrid powertrain including a retarded diesel engine, at least one electric machine and an electrical energy storage system, said diesel engine and said at least one electric machine both being operatively mechanically coupled to a driveline having an output in accordance with known speed relationships between the diesel engine, said at least one electric machine and said output, wherein output power is substantially equivalent to a summation of engine power and said at least one electric machine power, comprising: providing a vehicle braking request; providing a first braking contribution to the output by said at least one electric machine; providing a second braking contribution to the output by said retarded engine; controlling an engine speed higher when power flow to the energy storage system exceeds a predetermined power limit and lower when power flow to the energy storage system does not exceed the predetermined power limit; whereby increasing engine speed increases the second braking contribution and decreases the first braking contribution, decreasing the engine speed decreases the second braking contribution and increases the first braking contribution, and vehicle braking contribution priority is first to said at least one electric machine and second to said retarded engine.