Westport Power Inc.

Westport Fuel Systems Canada Inc.

Anuja S Bengali

Gregory A Batenburg

Gage D Garner

It is challenging to detect end of stroke for hydraulically actuated, reciprocating piston pumps for a variety of reasons. When the pump pressurizes a process fluid to a 10 relatively low pressure the magnitude of hydraulic fluid pressure is not as distinct compared to the magnitude of a pressure drop across a shuttle valve employed to detect end of stroke, which makes detecting the end of stroke event difficult. A method is disclosed for detecting end of a piston stroke in a hydraulic motor comprising a reciprocating piston with a shuttle valve. The method comprises 1 detecting end of piston stroke when a magnitude of a rate of change of hydraulic fluid pressure is substantially greater than a magnitude of a mean rate of change of hydraulic fluid pressure over said piston stroke; and noise in a hydraulic fluid pressure signal is substantially negligible.

Detecting end of stroke in a hydraulic motor

The problem arises of how to control a plurality of hydraulic pumps to achieve desired performance criteria, such as reduced wear and/or power consumption. The hydraulic pumps are operated in a hydraulic system for delivering hydraulic fluid to a hydraulic motor in a cryogenic pumping apparatus in an engine system fuelled with a gaseous fuel. A controller is operatively connected with the plurality of hydraulic pumps and is programmed to periodically determine a priority for each hydraulic pump as a function of predetermined criteria such as respective cumulative pumping cycles. Higher priority hydraulic pumps are operated before lower priority hydraulic pumps, that is in descending order of priority, to supply hydraulic fluid to the hydraulic motor. Hydraulic pumps are selected to operate according to the desired performance criteria.

Apparatus and method for operating a plurality of hydraulic pumps

A method and system is disclosed for delivering a cryogenically stored fuel in a gaseous state into the air intake system of a gaseous fuelled internal combustion engine. The method comprises determining the flow rate capacity in the engine system's fuel delivery line, comparing the determined flow rate capacity to a required flow rate demand and supplying fuel in gaseous state directly from the vapor space of the cryogenic storage vessel to the fuel delivery line that supplies fuel to the engine, when the flow rate capacity is equal to or higher than the required flow rate demand. The method further comprises activating a cryogenic pump to deliver fuel to the internal combustion engine from the liquid space of the cryogenic storage vessel when the determined flow rate capacity is lower than the required flow rate demand.

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Surrey, Canada

Anuja S Bengali