A simple engine, comprises (1) a cylinder and a spark plug in the cylinder; (2) a carburetor, fluidly connected to the cylinder; (3) a primary air intake path, fluidly connecting atmosphere to the carburetor; (4) a carburetor bypass air intake path, fluidly connecting air to the cylinder without passing through the carburetor; and (5) a valve, along the carburetor bypass air intake path, for controlling the flow of air through the carburetor bypass air intake path.

A simple engine, comprises (1) a cylinder and a spark plug in the cylinder; (2) a carburetor, fluidly connected to the cylinder; (3) a primary air intake path, fluidly connecting atmosphere to the carburetor; (4) a carburetor bypass air intake path, fluidly connecting air to the cylinder without passing through the carburetor; and (5) a valve, along the carburetor bypass air intake path, for controlling the flow of air through the carburetor bypass air intake path.

An engine includes a single cylinder, at least one sensor, a fuel injector, and a controller. The at least one sensor is configured to generate sensor data for an engine condition. The controller is configured to perform a comparison of the engine condition to a threshold and in response to the comparison, generate a first command to deactivate the fuel injector after a first predetermined time period and a second command to reactivate the fuel injector after a second predetermined time period.

An engine includes a single cylinder, at least one sensor, a fuel injector, and a controller. The at least one sensor is configured to generate sensor data for an engine condition. The controller is configured to perform a comparison of the engine condition to a threshold and in response to the comparison, generate a first command to deactivate the fuel injector after a first predetermined time period and a second command to reactivate the fuel injector after a second predetermined time period.

A balanced rotary engine for applying torque to a drive shaft. The engine has an outer casing with a main drive case. A cylinder is rotably mounted in the casing and a piston is mounted to move longitudinally within the cylinder. Two connecting arms, each with a connecting end, one of the ends is connected to the piston, and two crankshafts, each one being rotably connected to the other connecting end of the connecting arms. Two drive wheels are contra-rotably connected to the respective first and second crankshafts. A fixed drive ring has a circumferentially disposed drive member surface. The fixed drive ring is mounted in the case so that the drive member surface faces the piston. The two drive wheels mesh with the drive ring.

A balanced rotary engine for applying torque to a drive shaft. The engine has an outer casing with a main drive case. A cylinder is rotably mounted in the casing and a piston is mounted to move longitudinally within the cylinder. Two connecting arms, each with a connecting end, one of the ends is connected to the piston, and two crankshafts, each one being rotably connected to the other connecting end of the connecting arms. Two drive wheels are contra-rotably connected to the respective first and second crankshafts. A fixed drive ring has a circumferentially disposed drive member surface. The fixed drive ring is mounted in the case so that the drive member surface faces the piston. The two drive wheels mesh with the drive ring.

An internal combustion engine provides a cylinder able to rotate about a rotational axis L, a combustion chamber defined in the cylinder, and drive parts. The drive parts provides pistons housed in the cylinder able to slide in the rotational axis direction and defining a combustion chamber, slots formed in the circumferential surface of the cylinder, and followers extending from the pistons through the slots to the cams. The slots are configured to limit relative movement of the followers with the pistons to the cylinder in a circumferential direction of the rotational axis, allowing relative movement of the followers with the pistons to the cylinder in a direction of the rotational axis. Combustion performed in the combustion chamber moves the pistons with the followers along profiles of the cams to rotate the cylinder about the rotational axis, and the rotation of the cylinder is taken out as engine output.

An internal combustion engine provides a cylinder able to rotate about a rotational axis L, a combustion chamber defined in the cylinder, and drive parts. The drive parts provides pistons housed in the cylinder able to slide in the rotational axis direction and defining a combustion chamber, slots formed in the circumferential surface of the cylinder, and followers extending from the pistons through the slots to the cams. The slots are configured to limit relative movement of the followers with the pistons to the cylinder in a circumferential direction of the rotational axis, allowing relative movement of the followers with the pistons to the cylinder in a direction of the rotational axis. Combustion performed in the combustion chamber moves the pistons with the followers along profiles of the cams to rotate the cylinder about the rotational axis, and the rotation of the cylinder is taken out as engine output.

An internal combustion engine that can ensure an adequate cooling performance by using a small number of component parts, and can be minimized in size. The cooling device includes a boiling water cooling device including a water jacket, coolant piping, steam piping and a radiator, an air cooling fan connected to one end of a crankshaft projecting from an outer surface of the engine main body, and a cover member provided on the engine main body so as to cover the air cooling fan, and define a cooling air passage extending to a radiator core.

An engine includes a crankcase in which a crank chamber that houses a crankshaft is formed, a cylinder block that is attached to the crankcase, and a cylinder that is formed with a sliding surface with respect to a piston. The crankcase includes a partition wall that forms the crank chamber. A lower end of the cylinder protrudes into the crank chamber from a lower end of the cylinder block, and a communicating hole that connects inside and outside of the cylinder is formed on a side surface of the cylinder as viewed in an axial direction of the crankshaft. The partition wall is formed with an opening that is communicated with the communicating hole.