A gas engine is disclosed. The gas engine may include a combustion cylinder. The combustion cylinder may include an intake with an intake valve. The combustion cylinder may include an exhaust with an exhaust valve. The gas engine may include a gas admission valve assembly coupled to the intake. The gas admission assembly may include a trimmable electro-hydraulically actuatable gas admission valve to control a gas flow into the intake.

The present invention relates to a method for operating an internal combustion engine provided as a medium-speed gas engine or dual fuel engine in a gas fuel mode. The method comprises the step of directly injecting a gas fuel into a combustion chamber of the engine at a maximum injection pressure that is lower than a compression-end pressure of the engine.

The engines include compression cylinders, combustion cylinders, an air rail, and a heat exchanger. The methods of operating a compression ignition engine include taking air into a compression cylinder of the engine, compressing the air in the compression cylinder to raise the pressure and temperature of the air, passing the compressed air through a heat exchanger, and from the heat exchanger into a combustion cylinder, further compressing the compressed air during a compression stroke of the combustion cylinder, igniting fuel in the combustion cylinder at or near the end of the compression stroke by compression ignition, followed by a power stroke, and opening an exhaust valve at the end of the power stroke and passing at least some of the exhaust in the combustion cylinder through the heat exchanger to heat air that has been compressed in the compression cylinder and is then passing through the heat exchanger.

The engines include compression cylinders, combustion cylinders, an air rail, and a heat exchanger. The methods of operating a compression ignition engine include taking air into a compression cylinder of the engine, compressing the air in the compression cylinder to raise the pressure and temperature of the air, passing the compressed air through a heat exchanger, and from the heat exchanger into a combustion cylinder, further compressing the compressed air during a compression stroke of the combustion cylinder, igniting fuel in the combustion cylinder at or near the end of the compression stroke by compression ignition, followed by a power stroke, and opening an exhaust valve at the end of the power stroke and passing at least some of the exhaust in the combustion cylinder through the heat exchanger to heat air that has been compressed in the compression cylinder and is then passing through the heat exchanger.

Methods and systems are provided for maintaining combustion stability in a multi-fuel engine. In one example, a system may include first and second fuel systems to deliver liquid and gaseous fuels, respectively, to at least one cylinder of the engine, and a controller. The controller may be configured to supply the gaseous fuel to the at least one cylinder, inject the liquid fuel to the at least one cylinder to compression ignite the liquid fuel and combust the gaseous fuel in the at least one cylinder, and retard an injection timing of the injection of the liquid fuel based on a measured parameter associated with auto-ignition of end gases subsequent to the compression-ignition of the liquid fuel. In some examples, the controller may further be configured to adjust an amount of the gaseous fuel relative to an amount of the liquid fuel based on the measured parameter.

Methods and systems are provided for maintaining combustion stability in a multi-fuel engine. In one example, a system may include first and second fuel systems to deliver liquid and gaseous fuels, respectively, to at least one cylinder of the engine, and a controller. The controller may be configured to supply the gaseous fuel to the at least one cylinder, inject the liquid fuel to the at least one cylinder to compression ignite the liquid fuel and combust the gaseous fuel in the at least one cylinder, and retard an injection timing of the injection of the liquid fuel based on a measured parameter associated with auto-ignition of end gases subsequent to the compression-ignition of the liquid fuel. In some examples, the controller may further be configured to adjust an amount of the gaseous fuel relative to an amount of the liquid fuel based on the measured parameter.

The subject matter of this specification can be embodied in, among other things, a method performed in connection with an internal combustion engine, and the method including receiving a pressure signal from a combustion chamber pressure sensor during a first range of volumes, the first range corresponding to a portion of a compression phase, the received pressure being a first pressure, providing, based on the received pressure signal, a first pulse of fuel at a first position of the body during the compression phase, and providing, based on the received pressure signal a second pulse of fuel at a second position of the body during the compression phase.

The present disclosure describes an engine system that can achieve at least one of the followings: suppressing of generating of nitrogen oxides and suppressing of remaining of uncombusted hydrocarbons. The engine system has a combustion chamber to which air and a gas fuel are supplied, and is configured to combust the gas fuel. The engine system includes a liquid fuel injecting unit, and a control unit. The liquid fuel injecting unit is configured to inject a liquid fuel thereby to ignite the gas fuel. The control unit is configured to control the liquid fuel injecting unit. The control unit is configured to control the liquid fuel injecting unit so that injection of the liquid fuel is performed after a flame propagation after ignition of the gas fuel is ended.

Water Reservoirs and wetlands are a major source of methane emissions contributing to greenhouse gases. The annual flood seasons contribute to movement and accumulation of sediments behind irrigation and hydropower dams. These sediments accumulate year after year, lead to loss of water storage capacity and ability to produce hydro-electricity. The invention being proposed to dredge deep sediments from reservoirs operates on the principle of using gaseous fuel from an external pipeline or collected methane emissions as fuel for a submersible internal combustion slurry system. The invention combines the features of an internal combustion liquid piston engine with a slurry turbine driving a dredging cutter. Slurry entering into the system forms a column that is set in oscillation through the explosion of air and fuel and is then pumped to shore.

Water Reservoirs and wetlands are a major source of methane emissions contributing to greenhouse gases. The annual flood seasons contribute to movement and accumulation of sediments behind irrigation and hydropower dams. These sediments accumulate year after year, lead to loss of water storage capacity and ability to produce hydro-electricity. The invention being proposed to dredge deep sediments from reservoirs operates on the principle of using gaseous fuel from an external pipeline or collected methane emissions as fuel for a submersible internal combustion slurry system. The invention combines the features of an internal combustion liquid piston engine with a slurry turbine driving a dredging cutter. Slurry entering into the system forms a column that is set in oscillation through the explosion of air and fuel and is then pumped to shore.