Internal combustion engines that operate in an inverted orientation in which the piston is closer to the local gravitationally dominant terrestrial body's center of gravity at top dead center position than at bottom dead center position are disclosed. The engines may have non-circular, preferably rectangular, cross-section pistons and cylinders, and the pistons may include a skirt with a field of pockets that provide a ringless, non-lubricated, seal equivalent. The pistons also may have a domed piston head with depressions thereon to facilitate the movement of air/charge in the cylinder. The engines also may use multi-stage poppet valves in lieu of conventional poppet valves, and a split crankshaft. The engines may use the pumping motion of the engine piston to supercharge the cylinder with air/charge.

An internal combustion engine includes: a cylinder block including a bulkhead formed so as to separate adjacent cylinders; a crankshaft including a counterweight; and a gas-vent hole which is formed in the bulkhead within a radius of rotation of the counterweight when seen from below a piston bottom-dead-center position and an axial direction of the crankshaft, and which communicates between the adjacent cylinders. The counterweight includes at least one of a concave portion and a through-hole formed at at least a part of a region of the counterweight opposed to the gas-vent hole during rotation of the crankshaft. The concave portion hollows in a direction away from the gas-vent hole, the through-hole penetrating through the counterweight in a direction away from the gas-vent hole.

In an internal combustion engine in which a plurality of cylinders are arranged in series in a cylinder section, pressures of the cylinders can be detected by a smaller number of pressure sensors. An engine in which a plurality of cylinders are arranged in series in a cylinder section includes a communication path through which combustion chambers of the cylinders adjacent to each other communicate with each other, and a pressure sensor is disposed in the communication path.

A structural frame is provided herein. The structural frame may provide a lubrication passage that feeds a lubricant to a cylinder block. The structural frame may increase cylinder block strength while allowing a cylinder block to be constructed of less material.

A cylinder block for use in an internal combustion engine includes a first and second cylinder bores, a first and second cylinder bore liners, and a Siamese insert. The first and second cylinder bores are disposed adjacent to each other. The first and second cylinder bores each comprise a first cylinder bore wall and a second cylinder bore wall, respectively, and a shared cylinder bore wall. The first cylinder bore liner is disposed on a first inner surface of the first cylinder bore wall and the second cylinder bore liner is disposed on a second inner surface of the second cylinder bore wall. The Siamese insert is disposed in a top portion of the shared cylinder bore wall.

A ferritic aero diesel engine. The ferritic aero diesel engine includes an iron crankcase, a steel crankshaft and eight steel piston assemblies. The iron crankcase has a flat, horizontally opposed eight cylinder arrangement with a first set of cylinder walls defining a first set of cylinders in a first bank and a second set of cylinder walls defining a second set of cylinders in an opposed second bank. The steel crankshaft is rotatably mounted at least partially within the iron crankcase. Each of the steel piston assemblies of the plurality of steel piston assemblies is received within a respective cylinder of the iron crankcase and is coupled to the steel crankshaft. The first and second sets of cylinder walls have a minimum wall thickness of between approximately 4.8 and 5.2 mm.

An engine includes: a throttle body that is joined to an intake port and that makes a butterfly valve within an intake path actuate based on driving force of an electric actuator so as to adjust an opening degree of the intake path; a receptor that extends from the throttle body to a direction distant from the throttle body above a crankcase and that receives the electric actuator therein; and a supporting piece that extends from the receptor to the direction distant from the throttle body and that is supported on the crankcase. Accordingly, in the engine, it is possible to alleviate the influence of vehicle vibrations on the throttle body and actuator by enhancing the rigidity with which to support the throttle body and actuator in a simple structure.

A cylinder block assembly includes a cylinder block having cylinders and a plurality of crank caps fixed to the cylinder block. The crank caps are arranged such that one of the crank caps is disposed on each of both sides of each of the cylinders in the alignment direction and among the plurality of crank caps arranged in line, each of a center crank cap located at a center position and two side crank caps respectively located at both ends has a hole or a groove in such a manner as to be more easily deformable than intermediate crank caps each of which is located between the center crank cap and one of the side crank caps when a load is received from the crankshaft.

Systems and methods are provided for a cylinder block having one or more bulkheads. The bulkheads provide a dual-wall structure that may enhance the stiffness of the cylinder block in bending and torsion. The bulkheads may also provide an oil drain to allow oil to directly drain through a hollow core of the bulkhead. An overflow outlet may be formed in an inner wall of a bulkhead. In some implementations, a cylinder block with bulkheads may increase an oil capacity of an engine.

An internal combustion engine includes: a wall body that is formed on a crankcase to accommodate a generator by sandwiching the generator between the wall body and a generator cover coupled to the crankcase from outside; a casing that includes a casing wall, the casing wall being formed on the crankcase and, at a position apart from the wall body in an axial direction of the crankshaft, facing the wall body with a space contiguous to an outer surface of the crankcase sandwiched between the casing wall and the wall body; and a balancer shaft that has an axis thereof parallel to the rotation axis of the crankshaft, and is rotatably supported by the casing while one end of the balancer shaft protrudes from the casing wall into the space. Accordingly, the engine can reduce its weight by shortening the balancer shaft as much as possible without upsetting weight balance.