An engine system includes a combustion chamber including a cylinder formed in an engine and a piston configured to reciprocate inside the cylinder, a spark plug disposed in a ceiling part of the combustion chamber, and a water injection device configured to inject water into the combustion chamber through a plurality of nozzle holes facing the inside of the combustion chamber. The piston has a cavity in an upper surface thereof. The water injection device injects water into the cavity in a compression stroke at a timing when an extension of axes of at least some of the nozzle holes intersects the cavity. The cavity has a bottom part where the water injected by the water injection device collides, and a raising part configured to raise the water spreading along the bottom part toward the water injection device.

Method to control the combustion of a compression ignition engine with reactivity control through the injection temperature; the control method provides for the steps of: establishing a quantity of fuel to be injected into a cylinder; injecting a first fraction of the quantity of fuel fed by a first feed system without active heating devices, preferably equal to at least 70% of the quantity of fuel, at least partially during the intake and/or compression stroke; injecting a second fraction of the quantity of fuel fed by a second feed system provided with at least one active heating device, and equal to the remaining fraction of the quantity of fuel, into the cylinder at the end of the compression stroke and preferably at no more than 60 from the top dead center; and heating the second fraction of the quantity of fuel to an injection temperature of over 100 C., before injecting the second fraction of the quantity of fuel.

Method to control the combustion of a compression ignition engine with reactivity control through the injection temperature; the control method provides for the steps of: establishing a quantity of fuel to be injected into a cylinder; injecting a first fraction of the quantity of fuel fed by a first feed system without active heating devices, preferably equal to at least 70% of the quantity of fuel, at least partially during the intake and/or compression stroke; injecting a second fraction of the quantity of fuel fed by a second feed system provided with at least one active heating device, and equal to the remaining fraction of the quantity of fuel, into the cylinder at the end of the compression stroke and preferably at no more than 60 from the top dead center; and heating the second fraction of the quantity of fuel to an injection temperature of over 100 C., before injecting the second fraction of the quantity of fuel.

Hydraulically actuated gaseous fuel injectors required a relatively small pressure bias between hydraulic fluid and gaseous fuel to be able to open and to reduce hydraulic fluid contamination of the gaseous fuel. An improved hydraulically actuated gaseous fuel injector includes an injection valve in fluid communication with a gaseous fuel inlet and includes a valve member reciprocatable within a fuel injector body between a closed position and an open position. There is a lift chamber in fluid communication with a hydraulic fluid inlet such that hydraulic fluid pressure in the lift chamber contributes to an opening force applied to the valve member. A control chamber is in fluid communication with the hydraulic fluid inlet such that hydraulic fluid pressure in the control chamber contributes to a closing force applied to the valve member. A control valve is operable to reduce hydraulic fluid pressure in the control chamber such that the opening force is greater than the closing force and the valve member moves to the open position.

Hydraulically actuated gaseous fuel injectors required a relatively small pressure bias between hydraulic fluid and gaseous fuel to be able to open and to reduce hydraulic fluid contamination of the gaseous fuel. An improved hydraulically actuated gaseous fuel injector includes an injection valve in fluid communication with a gaseous fuel inlet and includes a valve member reciprocatable within a fuel injector body between a closed position and an open position. There is a lift chamber in fluid communication with a hydraulic fluid inlet such that hydraulic fluid pressure in the lift chamber contributes to an opening force applied to the valve member. A control chamber is in fluid communication with the hydraulic fluid inlet such that hydraulic fluid pressure in the control chamber contributes to a closing force applied to the valve member. A control valve is operable to reduce hydraulic fluid pressure in the control chamber such that the opening force is greater than the closing force and the valve member moves to the open position.

Hydraulically actuated gaseous fuel injectors required a relatively small pressure bias between hydraulic fluid and gaseous fuel to be able to open and to reduce hydraulic fluid contamination of the gaseous fuel. An improved hydraulically actuated gaseous fuel injector includes an injection valve in fluid communication with a gaseous fuel inlet and includes a valve member reciprocatable within a fuel injector body between a closed position and an open position. There is a lift chamber in fluid communication with a hydraulic fluid inlet such that hydraulic fluid pressure in the lift chamber contributes to an opening force applied to the valve member. A control chamber is in fluid communication with the hydraulic fluid inlet such that hydraulic fluid pressure in the control chamber contributes to a closing force applied to the valve member. A control valve is operable to reduce hydraulic fluid pressure in the control chamber such that the opening force is greater than the closing force and the valve member moves to the open position.

Hydraulically actuated gaseous fuel injectors required a relatively small pressure bias between hydraulic fluid and gaseous fuel to be able to open and to reduce hydraulic fluid contamination of the gaseous fuel. An improved hydraulically actuated gaseous fuel injector includes an injection valve in fluid communication with a gaseous fuel inlet and includes a valve member reciprocatable within a fuel injector body between a closed position and an open position. There is a lift chamber in fluid communication with a hydraulic fluid inlet such that hydraulic fluid pressure in the lift chamber contributes to an opening force applied to the valve member. A control chamber is in fluid communication with the hydraulic fluid inlet such that hydraulic fluid pressure in the control chamber contributes to a closing force applied to the valve member. A control valve is operable to reduce hydraulic fluid pressure in the control chamber such that the opening force is greater than the closing force and the valve member moves to the open position.

Method to control the combustion of a compression ignition engine with reactivity control through the injection temperature; the control method provides for the steps of: establishing a quantity of fuel to be injected into a cylinder; injecting a first fraction of the quantity of fuel fed by a first feed system without active heating devices, preferably equal to at least 70% of the quantity of fuel, at least partially during the intake and/or compression stroke; injecting a second fraction of the quantity of fuel fed by a second feed system provided with at least one active heating device, and equal to the remaining fraction of the quantity of fuel, into the cylinder at the end of the compression stroke and preferably at no more than 60 from the top dead centre; and heating the second fraction of the quantity of fuel to an injection temperature of over 100 C., before injecting the second fraction of the quantity of fuel.

Provided is an apparatus and method for operation of the apparatus that includes an onboard fuel reformer comprising a catalytic material, a shell containing the catalytic material enclosing an air/fuel mixture in a leak-free environment, an inlet to the shell for feeding the air and fuel, and an outlet to the shell for discharge of the reformate mixture at the completion of an air-fuel reaction, wherein a reactivity separation is provided for RCCI combustion between the reformate and the parent fuel, thereby enabling single-fuel RCCI.

A compression-ignition, opposed-piston engine using a low reactivity fuel as an ignition medium manages trapped temperature and trapped combustion residue within, and fuel injection into, the combustion chambers of the engine, and controls the compression ratio of the engine in order to realize reductions in emissions as well as improved fuel consumption efficiencies.