Abstract: A cycle-by-cycle skip-fire fuel-injection technique for pilot-ignited engines involve skip-firing selected combustion chambers when a low load condition is determined and modulating the fuel delivery to maintain the requisite engine power, while reducing pilot fuel quantity to a predetermined minimum. Overall pilot fuel consumption is thereby reduced.

Abstract: Premixed engines including dual fuel engines can experience abnormal combustion characteristics including misfire, pre-ignition and knock.

Abstract: Unconstrained rotational movement of an inner vessel with respect to an outer vessel at one end of a cryogenic storage vessel increases stress in supports at an opposite end. A storage vessel for holding a cryogenic fluid comprises an inner vessel defining a cryogen space and having a longitudinal axis, and an outer vessel spaced apart from and surrounding the inner vessel, defining a thermally insulating space between the inner and outer vessels. A structure for supporting the inner vessel within the outer vessel at one end comprises an inner vessel support bracket connected with the inner vessel, an outer vessel support bracket connected with the outer vessel, and an elongated support extending between and mutually engaging the inner and outer support brackets to constrain radial and rotational movement of the inner vessel with respect to the outer vessel and to allow axial movement of the inner vessel with respect to the outer vessel along the longitudinal axis.

Abstract: Sensor probes for capacitance-type liquid level sensors do not comprise an acceptable balance between cost, performance and durability for mobile applications. An improved sensor probe is provided. A first electrode comprises two or more first plate sections arranged in angular relationship with respect to each other. A second electrode comprises two or more second plate sections arranged in angular relationship with respect to each other. Spacers are located between the first and second electrodes such that each first plate section is spaced apart in parallel and substantially overlapping relationship with respective second plate sections. Fasteners securely fix the first and second electrodes in position.

Abstract: An intelligent pressure management system that controls the pressure inside a cryogenic tank between variable target vapor pressure values and/or ranges that are set as a function of system operating conditions, by actuating an actively controllable valve disposed on a gaseous fluid vapor conduit; and in some embodiments, additionally by actuating an actively controllable valve on a liquefied gaseous fluid conduit, based on a signal received from a pressure sensor that measures the pressure inside the pressurized tank. The variable target vapor pressure values and/or ranges are determined as a function of at least two system operating conditions which can include the vapor volume in the storage space; the fluid flow demanded by the use device; and a measured temperature parameter that correlates to the temperature of the fluid exiting a heater.

Abstract: 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.

Abstract: A supply of gaseous fuel on a tender car for fuelling a locomotive engine requires the coordination of a variety of operational modes to improve the safety and efficiency 10 when operating components for delivering, refueling, draining, capturing and storing gaseous fuel. A method and apparatus for managing a supply of gaseous on a tender car comprises receiving on the tender car a command signal from the locomotive commanding delivery of gaseous fuel from the tender car to the locomotive; transferring from the tender car at least one status signal to the locomotive indicating 1 status of the tender car; representing a plurality of operational modes of the tender car as a plurality of states; and transitioning between the plurality of states in response to the command signal and the at least one status signal.

Abstract: Fuel injection accuracy of gaseous fuel injectors is important for efficient engine operation. However, the performance of the injectors varies from part to part and across their lifetime, and when an injector is under performing according to its specification it is often unknown what is causing the problem. An apparatus for operating a gaseous fuel injector in an engine comprises a mass flow sensor that generates a signal representative of the mass flow rate of the gaseous fuel in a supply conduit in the engine.

Abstract: Disclosed are a fluid control system and method for controlling delivery of two variable pressure fluids to maintain a pressure bias between the two fluids within an end use device. The system employs an actively controlled vent valve which can be integrated into a fluid control module in preferred embodiments and is actuated to an open position to decrease fluid pressure in a first fluid supply line when a determined pressure differential reversal exceeds a predetermined threshold pressure differential reversal. The disclosed system is particularly useful in a high pressure direct injection (HPDI) multi-fueled engine system where the first fluid is a gaseous fuel and the second fluid is a liquid fuel. The fluid control system and method of controlling it provide for improved control of venting along with protecting system components from high back pressure and cross contamination of fluids.

Abstract: In previous control systems for engines that fuelled with a conventional fuel and an alternative fuel, a conventional fuel controller controlled fuelling for both fuels. This required extensive modifications to both the conventional fuel controller and an alternative fuel controller. A control system for an engine comprises a first control unit programmed to generate a first pulse width to actuate a first fuel injector to introduce a first fuel; a second control unit programmed to generate a second pulse width to actuate a second fuel injector to introduce a second fuel; and a communication line between the first and second control units. The first control unit determines a total fuel energy amount to be introduced by the first and second fuel injectors. The second control unit determines a first fraction of the total fuel energy amount to be from the first fuel and a second fraction of the total fuel energy amount to be from the second fuel.

Abstract: A system and method is disclosed for storing a fluid in a storage vessel in liquefied form and delivering it in gaseous form to an end user through a supply line. The system comprises a pressure relief circuit for returning the fluid from the supply line to the vessel when predetermined conditions are met. The pressure relief circuit comprises a return line connected to the supply line and the storage vessel, a diversion line to divert the fluid elsewhere and a switching device operable to direct the fluid to either one of the lines, as a function of predetermined conditions.

Abstract: In high horse power engines there are strict energy budgets allotted for each subsystem. It is a challenge for a gaseous fuel pumping system to supply the necessary gaseous fuel mass flow to the engine while staying within budget. A method for pressurizing a gaseous fuel supplied to an engine comprises providing first and second hydraulically actuated pumping apparatus comprising first and second shuttle valves in first and second hydraulic pistons respectively; and selectively communicating hydraulic fluid flow to the first and second hydraulically actuated pumping apparatuses. In a first mode hydraulic fluid is communicated through the first hydraulically actuated pumping apparatus to the second hydraulically actuated pumping apparatus. In a second mode hydraulic fluid is communicated through the second hydraulically actuated pumping apparatus to the first hydraulically actuated pumping apparatus.

Abstract: A piston seal assembly is disclosed comprising a seal and a seal energizer which supports the seal. The piston seal assembly comprises one component that is designed to position the seal energizer in a fixed axial position within the piston groove. In one embodiment, the seal energizer has the shape of a split ring with at least one of its lateral surfaces shaped to position the energizer in a fixed position within a piston groove. In other embodiments the piston seal assembly comprises a spacer that is positioned next to the seal energizer within the piston groove and is designed to position the seal energizer in a fixed axial position. The piston seal assembly can comprise a seal that has a portion which protrudes between the seal energizer and the piston groove wall such that it positions the seal energizer in a fixed axial position within the piston groove.

Abstract: A fuel injector, preferably a dual fuel injector, for an internal combustion engine is disclosed. The fuel injector comprises first and second valve needles (80, 100) arranged to control the injection of first and second fuels, first and second control chambers (88, 10) associated with the first and second valve needles (80, 100) respectively, a first control valve (26) comprising a first control valve member (48) and arranged to vary the pressure of a control fluid in the first control chamber (88) so as to cause opening and closing movement of the first valve needle (80), and a second control valve (28) comprising a second control valve member (60) and arranged to vary the control fluid 10 pressure in the second control chamber (110) so as to cause opening and closing movement of the second valve needle (100). The first and second control valve members (48, 60) are arranged for linear movement along a common control valve axis.

Abstract: A check valve with improved response time comprises a valve member which has a central portion of a substantially convex shape and a guide portion that surrounds the central portion. The central portion has a central convex curvature extending towards the outlet port of the check valve, in the direction of the fluid flow. The guide portion has a weight to area ratio that is smaller than the weight to area ratio of the central portion. Such a check valve has an overall reduced weight of the valve member allowing a faster response time when the valve switches between its closed and open positions.

Abstract: Hydraulically actuated gaseous fuel injectors required a relatively small pressure bias between hydraulic fluid and gaseous fuel to be able to open and to reduce hydraulic fluid contamination of the gaseous fuel. An improved hydraulically actuated gaseous fuel injector includes an injection valve in fluid communication with a gaseous fuel inlet and includes a valve member reciprocatable within a fuel injector body between a closed position and an open position. There is a lift chamber in fluid communication with a hydraulic fluid inlet such that hydraulic fluid pressure in the lift chamber contributes to an opening force applied to the valve member. A control chamber is in fluid communication with the hydraulic fluid inlet such that hydraulic fluid pressure in the control chamber contributes to a closing force applied to the valve member.

Abstract: A method for introducing a gaseous fuel into a combustion chamber of an internal combustion engine includes forming a non-ignitable mixture of the gaseous fuel and a gas including oxygen in a predefined mixture mass ratio within a predetermined range of tolerance having a pressure suitable for directly introducing the non-ignitable mixture into the combustion chamber during at least the compression stroke; and introducing the non-ignitable mixture directly into the combustion chamber.

Abstract: A method and a system control flow of fluid from a storage tank through a supply line to an end user. The system includes a valve that in its open position allows fluid flow from the storage tank to the end user and closes when the pressure in the fluid supply line drops below a predetermined set point. The storage tank is thereby isolated because the valve prevents fluid from flowing from the storage tank to the supply line when the pressure in the supply line is lower than a predetermined upper limit of the storage tank pressure. An end use that is particularly suited to the present system and method is a fuel storage and supply system for a natural gas powered internal combustion engine.

Abstract: A method for operating a gaseous-fuelled internal combustion engine by directly injecting the gaseous fuel into the combustion chamber is disclosed wherein the gaseous fuel is injected at injection pressures higher than 300 bar and the pressure ratio between the gaseous fuel injection pressure and the peak cylinder pressure is between 1.6:1 and 3:1, and preferably between 2.5:1 to 2.8:1. The injection pressure is selected to be between 300 and 540 bar and preferably between 300 bar and 440 bar. The injection pressure can be selected based on a preferred range for the pressure ratio.

Abstract: A fuel injector (100) for an internal combustion engine is disclosed. The fuel injector is particularly suitable for use as a dual fuel injector, and comprises a generally tubular outer valve needle (130), an inner valve needle (140) slidably received in the outer valve needle (130), and a nozzle body assembly (112) comprising a tip part (120) and a needle guide part (118). The tip part (120) defines a seating region (120f) for the outer valve needle (130), and the needle guide part (118) comprises a guide bore (118e) for slidably receiving the outer valve needle (130). In one embodiment, the tip part (120) and the needle guide part (118) are made from different materials, and a biasing spring (148) for the outer valve needle (130) is housed in the nozzle body assembly (112).