In a combustion cycle in which fuel for forming a homogenized air-fuel mixture in the combustion chamber is injected from the first fuel injector, ignition-use fuel for forming an ignition-use air-fuel mixture in the vicinity of the electrode part is injected from the second fuel injector, and lean combustion is performed by an excess air rate of 2.0 or more, the ignition-use fuel is injected by at least an injection rate of 1.0 mm.sup.3/ms or more for a duration of 250 μs or more in an interval from a crank angle advanced by exactly 20 degrees from an ignition timing of the spark plug to the ignition timing, and the quantity of the ignition-use fuel is 2.0 mm.sup.3/st or less.

A fuel bowl is disclosed. The fuel bowl comprises a body having an interior opposite an exterior, four sides, and a bottom opposite an opening. The opening is configured to be in fluid communication with a carburetor or an adaptor. The fuel bowl also comprises a fuel inlet port disposed in at least one of the four sides and configured to receive a gaseous fuel from a fuel regulator. The gaseous fuel expands and contracts within the body. A carburetor system is also disclosed. The carburetor system comprises a gaseous fuel, a fuel regulator configured to receive and deliver the gaseous fuel, a fuel bowl in fluid communication with the fuel regulator and a carburetor, a final fuel metering restriction disposed in an inlet supply port of a cylinder of the carburetor, and a venturi disposed in the carburetor.

System for adapting an internal combustion engine to be powered by gaseous fuel in gas phase and by gaseous fuel, an internal combustion engine arrangement comprising the system and a method for adapting an internal combustion liquid fuel engine to be powered by gaseous fuel in gas phase and gaseous fuel in liquid phase.

System for adapting an internal combustion engine to be powered by gaseous fuel in gas phase and by gaseous fuel, an internal combustion engine arrangement comprising the system and a method for adapting an internal combustion liquid fuel engine to be powered by gaseous fuel in gas phase and gaseous fuel in liquid phase.

A precombustion chamber gas engine including a precombustion chamber communicating with a main combustion chamber includes: a precombustion-chamber-fuel supply line through which a precombustion chamber fuel flows; a precombustion-chamber-fuel supply valve connected to the precombustion-chamber-fuel supply line and controlling supply of the precombustion chamber fuel to the precombustion chamber, the precombustion-chamber-fuel supply valve being configured to open when a precombustion chamber fuel line pressure, which is a pressure of the precombustion-chamber-fuel supply line, is larger than a precombustion chamber pressure, which is a pressure of the precombustion chamber; a precombustion-chamber-fuel-line-pressure adjustment valve disposed on the precombustion-chamber-fuel supply line and capable of adjusting the precombustion chamber fuel line pressure; an exhaust-precombustion-chamber-pressure acquisition unit capable of obtaining an exhaust precombustion chamber pressure which is a pressure related to the precombustion chamber pressure when an exhaust valve controlling a communication state between an exhaust passage and a cylinder forming the main combustion chamber is open; and a valve-opening-degree control device configured to control an opening degree of the precombustion-chamber-fuel-line-pressure adjustment valve. The valve-opening-degree control device is configured to control the opening degree of the precombustion-chamber-fuel-line-pressure adjustment valve in accordance with the exhaust precombustion chamber pressure obtained by the exhaust-precombustion-chamber-pressure acquisition unit.

A gas control system of a non-road gas engine and a gas control method thereof are disclosed by the present disclosure. The gas control system includes a mixer, the mixer is provided with an air inlet, a gas inlet and a mixed gas outlet respectively, the air inlet is provided with a first pressure sensor, the gas inlet is provided with a second pressure sensor and a pressure regulating valve that are spaced apart, and the mixed gas outlet is provided with a third pressure sensor; the first pressure sensor, the second pressure sensor, the pressure regulating valve and the third pressure sensor are respectively electrically connected to a controller, and the controller controls an opening degree of the pressure regulating valve according to pressure information fed back by the first pressure sensor, the second pressure sensor and the third pressure sensor so as to adjust an air-gas ratio of the mixed gas. The system has a simple structure. By disposing a pressure regulating valve at the gas inlet, the pressure of the gas entering the mixer is controlled, and the air-gas ratios required under various working conditions are controlled, which realizes a closed-loop control so that a control range of the air-gas ratio is smaller, the accuracy is higher, and a transient response speed of the engine is improved.

A method for operating a gas engine, or a dual-fuel engine operated in a gas fuel operating mode, the gas engine having a plurality of cylinders, structured to withstand ignition and combustion of an ignitable mixture of a gaseous fuel and combustion air, includes: preparing a non-ignitable premixture of the combustion air and the gaseous fuel; conducting the non-ignitable premixture toward the cylinders; adding further gaseous fuel to the non-ignitable premixture upstream of an inlet-side gas exchange valve via a gas valve assigned to a respective cylinder, so as to convert the non-ignitable premixture into the ignitable mixture; conducting, via the combustion air line, the ignitable mixture toward the cylinders; and providing the ignitable mixture to the respective cylinders.

Embodiments of the present invention include a method and apparatus for supplying conditioned natural gas to dual fuel engines.

An engine is equipped with a gas feeding system, including main gas injectors each associated with an intake duct of a respective engine cylinder, a gas distribution manifold communicating with said main injectors, a gas tank, connected to the manifold, where pressurized gas is accumulated, a controlled pressure valve interposed between the tank and manifold, and a control unit for controlling the pressure valve to establish a gas pressure in the manifold. A spark plug of each cylinder is mounted within a support body that defines a combustion pre-chamber and a channel for auxiliary gas injection within the pre-chamber, communicating with a respective auxiliary gas injector. The auxiliary gas injectors are in communication with the manifold, downstream of the pressure valve. In the channel, a non-return valve and a restricted passage are provided in series, providing for passage of gas flow proportional to a volume of the pre-chamber.

It is a challenge to reduce unburned hydrocarbon emissions for gaseous fuelled engines, especially at low engine load conditions, to meet demanding emission regulation targets. A method for reducing unburned hydrocarbon emissions in a lean-burn internal combustion engine that is fuelled with a gaseous fuel comprises adjusting the timing for closing of an intake valve as a function of engine operating conditions by one of advancing timing for closing of the intake valve and closing the intake valve earlier during an intake stroke; and retarding timing for closing of the intake valve and closing the intake valve later during a compression stroke. The volumetric efficiency of the internal combustion engine is reduced and unburned hydrocarbon emissions are maintained below a predetermined level.