A powertrain system includes a port injection internal combustion engine. A first start process is a process in which fuel is enclosed in a compression stroke cylinder when the engine is stopped, and based on a stored crank stop position, ignition is performed in a first cycle of the compression stroke cylinder upon engine start. A second start process is a process in which, based on the stored crank stop position, fuel injection is performed for an intake stroke cylinder while the engine is stopped, and based on the stored crank stop position, ignition is performed in the first cycle of the intake stroke cylinder upon engine start. When a catalyst temperature at the time engine start is requested is equal to or higher than a first threshold, a control device starts the internal combustion engine by at least one of the first start process and the second start process.

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.

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 cylinder head cover that prevents the gas outlet for the blow-by gas from being cooled by structural improvements so that the gas outlet does not freeze or become clogged in a cold condition. A cylinder head cover includes: a gas passage through which blow-by gas from a crankcase passes; and a gas outlet portion protruding upward from a head cover upper wall. The gas outlet portion includes a protruding case portion bulging upward from the head cover upper wall so as to form an outlet passage through which blow-by gas passes, and an air layer is formed outside the outlet passage in the protruding case portion.

A cylinder head cover that prevents the gas outlet for the blow-by gas from being cooled by structural improvements so that the gas outlet does not freeze or become clogged in a cold condition. A cylinder head cover includes: a gas passage through which blow-by gas from a crankcase passes; and a gas outlet portion protruding upward from a head cover upper wall. The gas outlet portion includes a protruding case portion bulging upward from the head cover upper wall so as to form an outlet passage through which blow-by gas passes, and an air layer is formed outside the outlet passage in the protruding case portion.

The application relates to internal combustion engines, cylinder heads, exhaust passages, and shapes and configurations of the exhaust passages. The exhaust passage may have cross-sectional shapes formed by two limbs. The cross-sectional shape of the exhaust passage may change as the passage extends. The exhaust passage may also merge with other exhaust passage. The exhaust passage may be part of a cylinder head or an exhaust manifold.

The application relates to internal combustion engines, cylinder heads, exhaust passages, and shapes and configurations of the exhaust passages. The exhaust passage may have cross-sectional shapes formed by two limbs. The cross-sectional shape of the exhaust passage may change as the passage extends. The exhaust passage may also merge with other exhaust passage. The exhaust passage may be part of a cylinder head or an exhaust manifold.

A method and system for assembling a vehicle of a family of vehicles includes providing a group of engines. A first engine including a first number of cylinders corresponds to a first vehicle. A second engine including a second number of cylinders corresponds to a second vehicle. The second number is greater than the first number which is at least one. A cylinder plane extends vertically and longitudinally. At least one cylinder is disposed at least partly forward of a front wheel plane. The transmission assembly is rearward of the selected engine and one of the transmission assembly and the selected engine is in a same location whether the selected engine is the first or the second. The seat is at least in part longitudinally rearward of the transmission assembly. The selected engine is laterally disposed between the centers of the footrests.

A method and system for assembling a vehicle of a family of vehicles includes providing a group of engines. A first engine including a first number of cylinders corresponds to a first vehicle. A second engine including a second number of cylinders corresponds to a second vehicle. The second number is greater than the first number which is at least one. A cylinder plane extends vertically and longitudinally. At least one cylinder is disposed at least partly forward of a front wheel plane. The transmission assembly is rearward of the selected engine and one of the transmission assembly and the selected engine is in a same location whether the selected engine is the first or the second. The seat is at least in part longitudinally rearward of the transmission assembly. The selected engine is laterally disposed between the centers of the footrests.

The present invention is directed to a dual engine-compressor system having a crankcase enclosing a crankshaft and having engine cylinder housings and compressor cylinder housings linearly disposed on opposite sides of the crankcase. Combustion pistons are reciprocatingly disposed in the engine cylinder housings and defines alternating combustion chambers on opposite sides of the pistons. Compressor pistons are reciprocatingly disposed in the compressor housings and define alternating low and high pressure compressor chambers on opposite sides of the compressor pistons. The compressor pistons undergo a 4-cycle process to drawn in, re-distribute, and then compress fluid. The compressor cylinder and piston has a series of one-way intakes and reed valves to selectively draw or push fluid in response to movement of the compressor piston.