Patent ID: 9188069
Filing Date: 2015-11-17
Classification: F02D,F02M,Y02T

Abstract:
1. A direct injection gas engine system, comprising: an engine including at least one engine cylinder that forms a variable volume between a reciprocating piston, a bore, and a flame deck; a liquid fuel system including a liquid fuel injector adapted to inject liquid fuel into the variable volume as an ignition source; a gaseous fuel system including a tank, a pumping element, a drive assembly, and a gaseous fuel injector, wherein: a controller in electrical communication with the drive assembly, the controller adapted to control the drive assembly such that the pumping piston moves in the intake direction over the intake stroke with an average intake velocity and moves in the power direction over the power stroke with an average power velocity, the average intake velocity being less than the average power velocity; wherein the drive assembly comprises: a hydraulic pump in electrical communication with the controller, the hydraulic pump adapted to provide a source of pressurized hydraulic fluid with a variable flow, a hydraulic actuator in selective fluid communication with the source of pressurized hydraulic fluid, the hydraulic actuator operably arranged with the pumping piston of the pumping element to selectively reciprocally move the pumping piston, and a directional control valve in electrical communication with the controller, the directional control valve in fluid communication with the source of pressurized hydraulic fluid and in selective fluid communication with the hydraulic actuator, the directional control valve including a valve element movable over a range of travel between an intake flow position, in which pressurized hydraulic fluid flows from the hydraulic pump to the hydraulic actuator such that the hydraulic actuator moves the pumping piston of the pumping element in the intake direction, and a power flow position, in which pressurized hydraulic fluid flows from the hydraulic pump to the hydraulic actuator such that the hydraulic actuator moves the pumping piston of the pumping element in the power direction, wherein the controller is adapted to selectively move the valve element between the intake flow position and the power flow position; wherein the controller is adapted to control the hydraulic pump such that pressurized hydraulic fluid flows with an average intake flow rate that is proportional to the average intake velocity of the pumping piston during the intake stroke when the valve element is in the intake flow position and such that pressurized hydraulic fluid flows with an average power flow rate that is proportional to the average power velocity of the pumping piston during the power stroke when the valve element is in the power flow position; and wherein the hydraulic actuator comprises a cylinder and a hydraulic piston reciprocally movable within the cylinder over a range of travel between a retracted position and an extended position, the hydraulic piston including a piston head and a rod extending from the cylinder, the rod of the hydraulic actuator being operably arranged with the pumping piston of the pumping element such that moving the hydraulic piston of the hydraulic actuator moves the pumping piston of the pumping element.