A large two-stroke turbocharged compression-ignited internal combustion crosshead engine with a plurality of cylinders has at least one pressure booster for each cylinder for boosting fuel pressure, two or more electronically controlled fuel valves for each cylinder with an inlet of the two or more electronically controlled fuel valves being connected to an outlet of the at least one pressure booster. An electronic control unit is connected to the at least one pressure booster and the two or more electronically controlled fuel valves. The electronic control unit is configured to determine a start time for a fuel injection event, activate the at least one pressure booster ahead of the determined start time and pen the two or more electronically controlled fuel valves at the determined start time.

Methods and systems are provided for fueling an engine with liquefied petroleum gas (LPG). In one example, a method may comprise pumping (LPG) from a fuel tank to a direct injection rail and not to a port injection rail. The method may further comprise supplying LPG from the direct injection rail to a port injection rail without returning the LPG to the fuel tank.

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. A controller connected with the injector and the mass flow sensor is programmed to actuate the injector to introduce gaseous fuel into the engine; determine the actual mass flow rate of the gaseous fuel based on the signal representative of the mass flow rate; calculate a difference between the actual mass flow rate and a desired mass flow rate; and adjust at least one of on-time of the gaseous fuel injector and a magnitude of an injector activation signal by respective amounts based on the difference when the absolute value of the difference is greater than a predetermined value.

Systems, apparatus and methods include control techniques for controlling operation of pre-mixed internal combustion engines in response to a load shedding event. The control techniques determine, in response to the load shedding event, a number of cycles in which to skip combustion of the fuel in the at least one cylinder based on an air-fuel ratio limit in the exhaust flow, prevent combustion of the fuel in the at least one cylinder during the number of skipped cycles, and combust the fuel in the at least one cylinder each time the number of skipped cycles are complete.

An injector, including: a moveable armature having a bore and upper and lower control surfaces; a lower housing including a bore and upper and lower stationary control surfaces; and a flow geometry defined along an exterior of the armature. The armature includes a transverse flow path fluidly coupled with the armature bore and the flow geometry. The lower housing includes a transverse flow path fluidly coupled with the lower housing bore. Upon moving the armature from a first position to a second position, a first flow path is formed between the flow geometry and the lower housing transverse flow geometry through a space between the lower stationary control surface and the lower armature control surface, and a second flow path is formed between the armature bore and the lower housing transverse flow geometry through a space between the upper stationary control surface and the armature upper control surface.

Provided is a fuel pressure monitoring system of a vaporizer using a safety module which issues a fault signal by detecting a pressure using a fuel pressure sensor disposed in a pressure regulating chamber of the vaporizer within a predetermined time after an engine is stopped and determining that the pressure regulating mechanism fails when the detected pressure exceeds a threshold stored in a storage device to be increased to a predetermined pressure or higher, and the pressure regulating mechanism is determined to fail only when a water temperature of cooling water in the engine of the vaporizer reaches a predetermined temperature at which warming up of the engine can be determined to be completed.

A large two-stroke turbocharged compression-ignited internal combustion crosshead engine with a plurality of cylinders has at least one pressure booster for each cylinder for boosting fuel pressure, two or more electronically controlled fuel valves for each cylinder with an inlet of the two or more electronically controlled fuel valves being connected to an outlet of the at least one pressure booster. An electronic control unit is connected to the at least one pressure booster and the two or more electronically controlled fuel valves. The electronic control unit is configured to determine a start time for a fuel injection event, activate the at least one pressure booster ahead of the determined start time and pen the two or more electronically controlled fuel valves at the determined start time.

A method of controlling a solenoid actuated fuel injector including applying a activation (pulse) profile to the solenoid, the activation profile including a hold phase, the hold phase including one or more hold pulses, and including a Pulse Width Modulation (PWM) scheme. The method includes determining the time period between the first hold pulse and the end of the previous pulse in the PWM scheme and increasing the energy of the activation profile if the time period is above a threshold.

A control system for a spark-ignited gaseous fuel engine includes a fuel quality sensing mechanism, and a control device structured to receive data produced by the fuel quality sensing mechanism indicative of a change in energy content of a stream of gaseous fuel and air, and to vary an amount of an augmenting fuel that is injected into the stream of gaseous fuel and air based on the data. The strategy has application to low energy gaseous fuel and air mixtures such as are produced in mine ventilation.

A gas engine is provided that suppresses fluctuation of the actual air-fuel ratio even when a load fluctuates. A gas engine (1) in which at least one opening degree (D) selected from the opening degree of an air supply valve (5a) and the opening degree of a bypass valve (5b) is corrected so that an adequate target air-fuel ratio (t) is achieved, wherein a target gas pressure (Pgt) and a target gas-jetting time (Tt) of a fuel gas are calculated on the basis of fluctuations of an actual load (L), the gas pressure is corrected on the basis of the target gas pressure (Pgt), and at least one opening degree selected from the opening degree of the air supply valve and the opening degree of the bypass valve is corrected on the basis of the amounts of change in the target gas pressure (Pgt) and the target gas-jetting time.