Abstract: Various systems are provided for delivering fuel to an engine. In one example, a system includes a controller and a fluid system configured to maintain a fluid at a pressure downstream of a check valve. The controller may be configured to determine if a leak is present in the fluid system based on a first pressure decay rate of the fluid system, and responsive to identifying that a leak is present in the fluid system, differentiate between an internal leak and an external leak based on a leak flow rate as fluid system pressure decreases.

Abstract: Various systems are provided for delivering fuel to an engine. In one example, a system includes a controller and a fluid system configured to maintain a fluid at a pressure downstream of a check valve. The controller may be configured to determine if a leak is present in the fluid system based on a first pressure decay rate of the fluid system, and responsive to identifying that a leak is present in the fluid system, differentiate between an internal leak and an external leak based on a leak flow rate as fluid system pressure decreases.

Abstract: Various methods and systems are provided for an intake manifold for an engine. In one example, the intake manifold comprises a first passage for supplying intake air to a plurality of cylinders of the engine and a second passage for supplying gaseous fuel to the plurality of cylinders.

Abstract: Various methods and systems are provided for adjusting an air-fuel ratio for combustion in an engine. In one embodiment, a method for an engine (e.g., a method for controlling an engine system) comprises responding to a sensed change in a load on the engine, or indications of engine knock or misfire, by one or more of: altering a speed of the engine, adjusting a fueling flow rate into at least one cylinder of the engine, and adjusting a position of a valve in a bypass passage configured to direct compressed intake air away from cylinders of the engine to obtain a determined air-fuel ratio; and thereby maintaining an air-fuel ratio in a determined range.

Abstract: Various methods and systems are provided for an intake manifold for an engine. In one example, an insert comprises an annular body having a top surface, bottom surface, inner surface, and outer surface. The insert further comprises a first groove for coupling an intake air port of an intake manifold to a cylinder head, a second groove for circulating gaseous fuel received from a gas runner of the intake manifold, and one or more openings to fluidically couple the second groove to an interior of the intake air port. The insert is configured to mix gaseous fuel and intake air at a coupling location between the intake manifold and the cylinder head.

Abstract: Various methods and systems are provided for adjusting an air-fuel ratio for combustion in an engine. In one embodiment, a method for an engine (e.g., a method for controlling an engine system) comprises responding to a sensed change in a load on the engine, or indications of engine knock or misfire, by one or more of: altering a speed of the engine, adjusting a fueling flow rate into at least one cylinder of the engine, and adjusting a position of a valve in a bypass passage configured to direct compressed intake air away from cylinders of the engine to obtain a determined air-fuel ratio; and thereby maintaining an air-fuel ratio in a determined range.

Abstract: Various systems are provided for delivering fuel to an engine. In one example, a system includes a controller and a fluid system configured to maintain a fluid at a pressure downstream of a check valve. The controller may be configured to determine if a leak is present in the fluid system based on a first pressure decay rate of the fluid system, and responsive to identifying that a leak is present in the fluid system, differentiate between an internal leak and an external leak based on a leak flow rate as fluid system pressure decreases.

Abstract: Various methods and systems are provided for an intake manifold for an engine. In one example, the intake manifold comprises a first passage for supplying intake air to a plurality of cylinders of the engine and a second passage for supplying gaseous fuel to the plurality of cylinders.

Abstract: Various methods and systems are provided for an intake manifold for an engine. In one example, an insert comprises an annular body having a top surface, bottom surface, inner surface, and outer surface. The insert further comprises a first groove for coupling an intake air port of an intake manifold to a cylinder head, a second groove for circulating gaseous fuel received from a gas runner of the intake manifold, and one or more openings to fluidically couple the second groove to an interior of the intake air port. The insert is configured to mix gaseous fuel and intake air at a coupling location between the intake manifold and the cylinder head.