An engine system includes a first cylinder including a first piston, a second cylinder including a second piston, and a fuel injector fluidly connected to the first cylinder. The first cylinder is a combustion cylinder, and the second cylinder is an expansion cylinder. The second cylinder is fluidly connected to the first cylinder when the first piston is in at least one position in the first cylinder. The fuel injector is configured to deliver hydrogen gas to the first cylinder.

An engine system includes a first cylinder including a first piston, a second cylinder including a second piston, and a fuel injector fluidly connected to the first cylinder. The first cylinder is a combustion cylinder, and the second cylinder is an expansion cylinder. The second cylinder is fluidly connected to the first cylinder when the first piston is in at least one position in the first cylinder. The fuel injector is configured to deliver hydrogen gas to the first cylinder.

Embodiments of apparatus are disclosed for affecting working fluid flow in a system that delivers material between two locations by carrying the material in the working fluid. For example, embodiments of the disclosed apparatus may be used in an internal combustion engines to carry fuel droplets to a combustion area using air as the working fluid. The apparatus may include a passage including a funnel portion and tumble area that direct working fluid into a stratified stream. The stratified stream may include an outer boundary flow having a toroidal and/or helical flow characteristic and an inner flow carrying injected material that is bound by the outer flow.

Embodiments of apparatus are disclosed for affecting working fluid flow in a system that delivers material between two locations by carrying the material in the working fluid. For example, embodiments of the disclosed apparatus may be used in an internal combustion engines to carry fuel droplets to a combustion area using air as the working fluid. The apparatus may include a passage including a funnel portion and tumble area that direct working fluid into a stratified stream. The stratified stream may include an outer boundary flow having a toroidal and/or helical flow characteristic and an inner flow carrying injected material that is bound by the outer flow.

An internal combustion engine in which a fuel reforming operation in a fuel reformation cylinder is not executed and a warming operation for raising the temperature of the fuel reformation cylinder is executed, when a gas temperature of a fuel reformation chamber at a time point when a piston in the fuel reformation cylinder reaches a compression top dead point is estimated to fall short of a reforming operation allowable lower limit gas temperature. For example, EGR gas is introduced to the fuel reformation chamber without cooling the EGR gas. Further, during a predetermined period from the expansion stroke to an exhaust stroke of an output cylinder, exhaust gas warming fuel is supplied to a combustion chamber. Further, the fuel is combusted in the fuel reformation chamber.

An internal combustion engine in which a fuel reforming operation in a fuel reformation cylinder is not executed and a warming operation for raising the temperature of the fuel reformation cylinder is executed, when a gas temperature of a fuel reformation chamber at a time point when a piston in the fuel reformation cylinder reaches a compression top dead point is estimated to fall short of a reforming operation allowable lower limit gas temperature. For example, EGR gas is introduced to the fuel reformation chamber without cooling the EGR gas. Further, during a predetermined period from the expansion stroke to an exhaust stroke of an output cylinder, exhaust gas warming fuel is supplied to a combustion chamber. Further, the fuel is combusted in the fuel reformation chamber.

A combination for an opposed-piston engine includes an intake piston and an exhaust piston, each with a top land height. The intake piston top land height is less than the exhaust piston top land height.

A combination for an opposed-piston engine includes an intake piston and an exhaust piston, each with a top land height. The intake piston top land height is less than the exhaust piston top land height.

A combination for an opposed-piston engine includes an intake piston and an exhaust piston, each with a top land height. The intake piston top land height is less than the exhaust piston top land height.

A combination for an opposed-piston engine includes an intake piston and an exhaust piston, each with a top land height. The intake piston top land height is less than the exhaust piston top land height.