An exhaust valve system for a two-stroke internal combustion engine having: at least one exhaust valve movable between open and closed positions; an actuator for moving the at least one exhaust valve; a valve position sensor; a controller communicating with the actuator and the valve position sensor. The controller being programmed for: controlling the actuator to attempt to move the at least one exhaust valve to a desired one of the open and closed positions; determining if the at least one exhaust valve has failed to reach the desired position based on the position of the at least one exhaust valve sensed by the valve position sensor; and controlling the actuator to move the at least one exhaust valve to an intermediate position when the at least one exhaust valve has failed to reach the desired position.

An exhaust valve system for a two-stroke internal combustion engine having: at least one exhaust valve movable between open and closed positions; an actuator for moving the at least one exhaust valve; a valve position sensor; a controller communicating with the actuator and the valve position sensor. The controller being programmed for: controlling the actuator to attempt to move the at least one exhaust valve to a desired one of the open and closed positions; determining if the at least one exhaust valve has failed to reach the desired position based on the position of the at least one exhaust valve sensed by the valve position sensor; and controlling the actuator to move the at least one exhaust valve to an intermediate position when the at least one exhaust valve has failed to reach the desired position.

A steel piston with an engineered coating is provided. A high thermal conductivity material, for example copper, is disposed on first regions of a combustion bowl to reduce hot spots in the piston. A low thermal conductivity material, for example a ceramic, is disposed on second regions of the combustion bowl to reduce loss of heat through the piston. The high thermal conductivity material disposed on the combustion bowl has a surface roughness (R.sub.a) of less than 5 μm to help reflect IR radiation and promote fuel flow. The low thermal conductivity material disposed on the combustion bowl has a surface roughness (R.sub.a) of less than 3 μm to promote fuel flow. The low thermal conductivity material is also disposed on the bowl rim and top ring land, and has a surface roughness (R.sub.a) of greater than 8 μm on the bowl rim and top ring land to retard gas flow.

A steel piston (1) for a combustion engine, having an upper part in which a ring section (7) with at least one ring groove (8) is arranged, wherein the upper part is adjoined by a lower part that has two opposing skirt wall sections (2), wherein the two skirt wall sections (2) are connected via two mutually opposite case walls (3), wherein a pin bore (4) surrounded by a piston boss (6) is provided in each case wall (3). In one example, there is at least one aperture (14) or at least one recess in the case wall (3) in the region between the piston boss (6) and the skirt wall section (2).

A piston for a high temperature internal combustion engine is provided. The piston includes an upper wall, base wall, outer rib, and inner rib defining a cooling chamber therebetween, and a plurality of ring grooves formed in the outer rib. Only the second ring groove is formed with the keystone cross-section, and all of the other ring grooves are formed with the conventional rectangular cross-section. Thus, the piston can be formed with low manufacturing costs and can also provide exceptional performance when used in high temperature combustion engines, wherein the temperature at the first ring groove is greater than 280° C., and thus prevents carbon from depositing or burns off any carbon deposits, but the temperature at the second ring groove is between 200° C. and 280° C., in which case carbon deposits can form and cause the piston ring to stick.

A piston for a high temperature internal combustion engine is provided. The piston includes an upper wall, base wall, outer rib, and inner rib defining a cooling chamber therebetween, and a plurality of ring grooves formed in the outer rib. Only the second ring groove is formed with the keystone cross-section, and all of the other ring grooves are formed with the conventional rectangular cross-section. Thus, the piston can be formed with low manufacturing costs and can also provide exceptional performance when used in high temperature combustion engines, wherein the temperature at the first ring groove is greater than 280° C., and thus prevents carbon from depositing or burns off any carbon deposits, but the temperature at the second ring groove is between 200° C. and 280° C., in which case carbon deposits can form and cause the piston ring to stick.

An aluminum alloy having excellent high temperature strength and thermal conductivity; and an internal combustion engine piston including the alloy. The aluminum alloy includes 11.0-13.0% Si, ≤0.3% Fe, 0.3-2.0% Mg, 2.0-5.0% Cu, 3.0-4.0% Ni, 0.2-1.0% Mn, 0.05-0.4% Cr, and 0.05-0.4% V, with the remainder including aluminum and unavoidable impurities.

A cylinder liner is provided that includes a cylinder bore capable of housing a piston, a top end having an annular flange, a first cylindrical section, a second cylindrical section, and an annular ridge that separates the first cylindrical section and the second cylindrical section. When employed in an a liner bore of an engine bock, the cylinder liner provides for two channels that allow for coolant to be supplied to the cylinder liner.

A cylinder liner is provided that includes a cylinder bore capable of housing a piston, a top end having an annular flange, a first cylindrical section, a second cylindrical section, and an annular ridge that separates the first cylindrical section and the second cylindrical section. When employed in an a liner bore of an engine bock, the cylinder liner provides for two channels that allow for coolant to be supplied to the cylinder liner.

Linear generators with a piston having a valve are described herein. The linear generator includes a combustion module and at least one linear motor. The linear motor includes at least one piston having: a piston head with an opening therein; a piston skirt opposed to the piston head; a piston side wall extending between the piston head and the piston skirt, the piston side wall having at least one port therein. The piston also includes a valve mechanism movable relative to each of the piston head, the piston seat and the piston side wall. The valve mechanism includes a valve stem extending through the piston skirt and the interior piston volume into a mover shaft of the motor, and a valve head coupled to the valve stem and configured to cover the opening of the piston head.