Compression Ignition Engine with Staged Ignition

A compression ignition combustion method for an internal combustion engine, a first part and a second part of the internal combustion engine defining a combustion chamber, the combustion chamber defining an axial direction, wherein the first part and the second part are movable with respect to one another in the axial direction, and wherein the first part has formed thereon a barrier projecting in the axial direction, the barrier defining a first zone spaced radially from a second zone within the combustion chamber, the method comprising:

• supplying an initial fuel charge into a combustion chamber;
• supplying a subsequent fuel charge into the first zone of the combustion chamber after the supplying the initial fuel charge, a composition of a fuel of the subsequent fuel charge being the same as a composition of a fuel of the initial fuel charge, and a concentration of the fuel of the subsequent fuel charge, in the subsequent fuel charge as injected, being greater than a concentration of the fuel of the initial fuel charge in the initial fuel charge;
• and
• compressing the fuel charges within the combustion chamber to induce ignition and combustion of the fuel charges, the ignition and combustion of the fuel charges including burning the subsequent fuel charge within the first zone to produce hot gases, and flowing the hot gases across the barrier to effect combustion of the initial fuel charge within the second zone.

An internal combustion engine comprising:

• an engine block defining a cylinder therein with an axis;
• a first part mounted within the cylinder;
• a second part forming a part of the engine block or mounted within the cylinder, a surface of the first part facing a surface of the second part, wherein the first part is movable within the cylinder along the axis to vary a distance between the surface of the first part and a surface of the second part;
• a barrier defined by portions of the first part or the second part extending axially within the cylinder to define a first region and a second region spaced radially from the first region by the barrier;
• an air intake for effecting fluid communication between a source of air and the cylinder;
• an injector fluidly connected to a source of a first fuel, and disposed to inject said first fuel into the first region within the cylinder;
• a source of a second fuel in fluid communication with the cylinder to introduce the second fuel substantially homogeneously into gases in the cylinder including the first and the second region prior to the introduction of the first fuel into the first region, a reactivity of the second fuel being lower than a reactivity of the first fuel;
• and
• the first part being actuated with respect to the second part to drive the first part closer to the second part so as to compress gases within the cylinder and cause combustion of the first fuel in the first region prior to combustion of the second fuel in the second region, the combustion of the first fuel in the first region causing a quantity of hot gases to pass across the barrier to ignite the second fuel in the second region.

A compression combustion method for a diesel internal combustion engine, the method comprising the steps of:

• supplying a substantially homogeneous charge of fuel and combustion air into a cylindrical combustion chamber of the diesel internal combustion engine, wherein the cylindrical combustion chamber defines a cylinder axis;
• wherein when the engine has a BMEP of 1 to 6 bar the charge has an AFR of 35 to 50 and an EGR % of 0 to 40, when the engine has a BMEP of 6 to 14 bar the charge has an AFR of 22 to 35 and EGR % of 20 to 40, and when the engine has a BMEP of 14 to 22 bar the charge has an AFR of 15 to 35 and an EGR % of 30 to 60;
• wherein a combustion chamber is defined between a cylindrical wall of an engine block and a piston and a second piston or a piston head formed by the engine block;
• wherein the piston is movable with respect to the second piston or the piston head;
• wherein the piston or the piston head has formed thereon an axially projecting barrier, the barrier defining a first zone spaced radially from a second zone within the combustion chamber;
• igniting one of the first zone and the second zone defining a first ignited zone by injecting fuel when the piston is between 30° and 1 ∞ before top dead center into one of the first zone and the second zone, creating a fuel rich volume, and further compressing the charge as the piston moves to top dead center until the fuel rich volume ignites;
• and
• igniting the other of the first zone or the second zone, by allowing combustion gases to flow over the axially projecting barrier through a gap between the barrier and a cylinder head or a second piston so that the flow accelerates through the gap in a first direction and compresses and ignites a portion of the charge in the other of the first or second zone, wherein the portion of the charge of the other of the first or second zone, after ignition, expands and causes a flow through the gap in a second direction opposite the first direction which enters the first ignited zone and lowers a temperature of the first ignited zone.