A two-stroke engine has a cylinder with a combustion chamber formed therein. The combustion chamber is delimited by a piston. The cylinder has a base on which extends a partition plane whereat the cylinder is separated from a crankcase. The combustion chamber is, in at least one piston position, connected via at least one transfer channel to the crankcase interior. The transfer channel passes from the cylinder into the crankcase at at least one opening. A side wall of the transfer channel has, in the cylinder, a first region wherein the wall encloses an angle of 90 with the cylinder longitudinal axis. Between the first region and the opening as viewed in the cylinder circumferential direction is arranged a second wall region. The second region has a spacing, measured parallel to the cylinder longitudinal axis, to the partition plane. The spacing is greater than the spacing in the first region.

With shaped connecting rod, piston and cylinder, an advantageous asymmetric timing of the two-stroke engine is achieved, wherein the combustion chamber communicates with the crankcase through a transfer port controlled by the piston and through a respective piston port controlled by the connecting rod, with the transfer port and its respective piston port arranged in series, and wherein an intake port communicates with the crankcase through a piston port controlled by the connecting rod, with the intake port and its respective piston port arranged in series.

To balance a low-temperature scavenging effect and a high-temperature scavenging effect. A scavenging system applicable to a leading-air type two-stroke air-cooled engine has a low-temperature scavenging passage and a high-temperature scavenging passage. The low-temperature scavenging passage has first and second passages and includes scavenging ports at upper end parts thereof. The high-temperature scavenging passage has first and second passages and includes scavenging ports at upper end parts thereof. An air is filled through a piston groove into the passages. The low-temperature scavenging passage has a relatively small capacity. The high-temperature scavenging passage has a relatively large capacity.

A method for controlling valve timing of a turbo engine may include: classifying by a controller control regions depending on an engine speed and an engine load, and the control regions may include first, second, third, fourth, fifth, and sixth control regions. The method further includes: applying a maximum duration to an intake valve and controlling a valve overlap in the first control region; applying the maximum duration to the intake valve and exhaust valve in the second control region; advancing an intake valve closing (IVC) timing and an exhaust valve closing (EVC) timing in the third control region; approaching the IVC timing to a bottom dead center in a fourth control region; controlling a wide open throttle valve (WOT) in the fifth control region; and controlling the WOT and the IVC timing to reduce the knocking in the sixth control region.

A method for controlling valve timing of a turbo engine may include: classifying by a controller control regions depending on an engine speed and an engine load, and the control regions may include first, second, third, fourth, fifth, and sixth control regions. The method further includes: applying a maximum duration to an intake valve and controlling a valve overlap in the first control region; applying the maximum duration to the intake valve and exhaust valve in the second control region; advancing an intake valve closing (IVC) timing and an exhaust valve closing (EVC) timing in the third control region; approaching the IVC timing to a bottom dead center in a fourth control region; controlling a wide open throttle valve (WOT) in the fifth control region; and controlling the WOT and the IVC timing to reduce the knocking in the sixth control region.

Provided is a modified two-stroke engine with an intake system having a plurality of removable inserts and a cylinder liner for each cylinder bore. The inserts fit within specific cavities in the engine's cylinder bores and are aligned with corresponding intake ports, upper transfer, lower transfer and central boost ports, in each liner. Certain embodiments may include an exhaust insert for the exhaust port. The exhaust insert can be a single piece or a set of three. Also provided is an engine having a billet aluminum block, forged as one piece, cylinder bores, insert cavities, removable intake inserts, pucks to cover the cylinder bores, a cylinder head base with a ring and a cylinder head cap. The ring prevents the separation of liner from water jacket. The power output of the engine is regulated by varying the size of the inserts. Additionally, methods for assembling, tuning and modifying an engine's horsepower are provided.

A system and method of stabilizing combustion in the engine of a hybrid electric vehicle. The system includes a controller controlling a starter and an injector, wherein the controller causes the starter to rotate the engine without fuel injection before starting the engine after an engine starting condition is satisfied or after an engine stop condition is satisfied and the engine is stopped.

A compact construction for an opposed-piston engine includes a cylinder liner with longitudinally-spaced exhaust and intake ports in which the exhaust port has inner and outer edges presenting a port height that causes the exhaust port to be fully open before a piston associated with the exhaust port reaches bottom dead center during an expansion stroke and the end surface of the associated piston to be spaced outwardly of the outer edge when the piston is at bottom dead center.

A two-stroke engine has a cylinder and a transfer channel which, in the region at bottom dead center of a piston, establishes a flow connection between a crankcase interior and the combustion chamber. The crankcase has a crankcase connecting flange for connecting to the cylinder, which has a first connecting opening and a second connecting opening. The transfer channel passes into the crankcase at the first connecting opening or the second connecting opening. At the other of the first and second connecting openings, no transfer channel passes into the crankcase. For a production series of two-stroke engines, provision is made, in one two-stroke engine of the series, which has a first cylinder, for a second connecting opening to be closed off from the cylinder, and, in one two-stroke engine of the series, which has a second cylinder, for the first connecting opening to be closed off by the cylinder.

The control system of the internal combustion engine comprises a control part controlling an air-fuel ratio of the exhaust gas flowing into the exhaust purification catalyst. The control part alternately sets a target air-fuel ratio between a rich air-fuel ratio and a lean air-fuel ratio and controls the air-fuel ratio of the exhaust gas so that an output air-fuel ratio of the air-fuel ratio sensor becomes the target air-fuel ratio. The control part corrects the output air-fuel ratio of the air-fuel ratio sensor so that when a scavenging occurs, the air-fuel ratio of the exhaust gas changes to a rich side more than an amount of deviation expected to occur in the output air-fuel ratio due to the occurrence of the scavenging. The control part increases a lean degree of the target air-fuel ratio when the scavenging occurs compared with when the scavenging does not occur.