Patent ID: 8337358

Claim:
A multi-mode hybrid transmission comprising: an input member; an output member; an electric motor; first, second, third and fourth clutches; first and second shift valves; first, second, third, and fourth trim valves; wherein each of said shift valves and said trim valves are configured to control fluid pressure to a respective one of said first, second, third, and fourth clutches; an electronic control unit (ECU) electrically operatively connected to each of said shift valves and said trim valves to selectively engage in combinations of at least two of said first, second, third, and fourth clutches and provide a clutch configuration to operate in at least one of a first electronic variable transmission (EVT) mode, a second EVT mode, a third EVT mode, a fourth EVT mode, a first fixed gear mode, a second fixed gear mode, and a third fixed gear mode, in which the speed ratio between the input member and the output member is dependent upon the speed of said at least one electric motor; and a hydraulic control unit (HYD); wherein said first clutch and said third clutch are engaged in said first EVT mode; wherein said first clutch and said fourth clutch are engaged in said second EVT mode; wherein said second clutch and said fourth clutch are engaged in said third EVT mode; wherein said second clutch and said third clutch are engaged in said fourth EVT mode; wherein said first clutch, said third clutch, and said fourth clutch are engaged in said first fixed gear mode; wherein said first clutch, said second clutch, and said fourth clutch are engaged in said second fixed gear mode; wherein said second clutch, said third clutch, and said fourth clutch are engaged in said third fixed gear mode; wherein said HYD provides fluid to each of said shift valves and said trim valves to maintain said clutch configuration in one of said EVT modes when said electrical operative connection to said ECU is off; wherein said HYD provides fluid to each of said shift valves and said trim valves to move said clutch configuration from one of said fixed gear modes to a next lowest one of said EVT modes when said electrical operative connection to said ECU is off.