Method and apparatus for coupling the output members of multiple power sources

A power unit comprising:

• a first power source having a first rotational output member;
• a second power source having a second rotational output member;
• a one-way clutch having a clutch input and a clutch output, the clutch input being rotatably coupled to the second rotational output member, the one-way clutch being operable in an unlocked condition, which inhibits torque transmission between the clutch input and the clutch output, and a locked condition, which permits torque transmission between the clutch input and the clutch output;
• a power input mechanism with a first input, a second input and a transmission output, the first input being coupled for rotation with the first rotational output member, the second input being coupled for rotation with the clutch output, the transmission output being rotatably coupled to the transmission input member;
• and
• a controller for controlling the first power source and the second power source, the controller determining when a power demand on the transmission exceeds a predetermined power demand threshold and in response thereto, controls the second power source to accelerate the second rotational output member at a first predetermined rate of acceleration until a rotational speed of the second rotational output member is less than a rotational speed of the first rotational output member by a first predetermined threshold, and thereafter accelerate the second rotational output member at a second predetermined rate of acceleration until the rotational speed of the second rotational output member is equal to the rotational speed of the first rotational output member, the second predetermined rate of acceleration being less than the first predetermined rate of acceleration and the second predetermined threshold being less than the first predetermined threshold, and thereafter control the one-way clutch, indirectly, to operate in the locked condition.

In a power unit having a first power source, a second power source and a power input mechanism, the first power source having a first rotational output member for inputting a first torque to the power input mechanism, the second power source having a second rotational output member for inputting a second torque to the power input mechanism, a method for coupling the first and second rotational output members, the method comprising the steps of:

• operating the first power source such that all of the torque input to the power input mechanism is supplied by the first power source;
• operating the second power source such that a rotational speed of the second rotational output member is matched to a rotational speed of the first rotational output member;
• coupling the first and second rotational output members;
• and
• simultaneously controlling the first and second power sources such that the rotational speeds of first and second rotational output members remain matched and a ratio of power supplied to the power input mechanism by the second and first power sources increases from 0:1 to a predetermined ratio.