An intake structure of the present invention is applied to a multi-cylinder engine including an electrically controlled throttle integrally including a throttle valve configured to adjust an amount of air to be supplied to the engine and an electronic control unit configured to control the throttle valve. The engine intake structure includes: an air cleaner configured to purify the air; and an intake manifold configured to distribute the air purified by the air cleaner to an intake port of each cylinder of the multi-cylinder engine. The electrically controlled throttle is attached to the intake manifold such that the electronic control unit is separated outward in a radial direction of an engine rotation shaft.

The present disclosure provides a six-cylinder opposed free piston internal combustion engine generator. The generator comprises two free piston internal combustion engine sets, one opposed piston internal combustion engine set and two linear generator sets. Air entering cylinders is subjected to first-stage compression in low-pressure cylinder sets in the free piston internal combustion engine sets and the opposed piston internal combustion engine set and then subjected to second-stage compression in high-pressure cylinder sets, and a high pressure gas produced after the combustion is subjected to first-stage expansion in the high-pressure cylinder sets and then subjected to second-stage expansion in the low-pressure cylinder sets. The technical problem about how to improve the power generation efficiency of the opposed free piston generator and improve the reliability of the device is solved, the six-cylinder opposed free piston internal combustion engine generator is provided, a dual piston dual cylinder type free-piston internal combustion engine linear generator is used for replacing a return device in the opposed free piston generator, and the reliability and the power generation efficiency of the device are improved.

The present disclosure provides a six-cylinder opposed free piston internal combustion engine generator. The generator comprises two free piston internal combustion engine sets, one opposed piston internal combustion engine set and two linear generator sets. Air entering cylinders is subjected to first-stage compression in low-pressure cylinder sets in the free piston internal combustion engine sets and the opposed piston internal combustion engine set and then subjected to second-stage compression in high-pressure cylinder sets, and a high pressure gas produced after the combustion is subjected to first-stage expansion in the high-pressure cylinder sets and then subjected to second-stage expansion in the low-pressure cylinder sets. The technical problem about how to improve the power generation efficiency of the opposed free piston generator and improve the reliability of the device is solved, the six-cylinder opposed free piston internal combustion engine generator is provided, a dual piston dual cylinder type free-piston internal combustion engine linear generator is used for replacing a return device in the opposed free piston generator, and the reliability and the power generation efficiency of the device are improved.

This invention has two main embodiments. An opposed piston 2-stroke axial engine and a 4-stroke axial engine. The opposed piston two stroke also offers an option of a novel cylinder deactivation design. Both, two stroke and four stroke engines share novel systems for coupling piston reciprocation to shaft rotation, piston and piston ring lubricant distribution, and provision for reacting out piston side load with minimum mechanical friction

This invention has two main embodiments. An opposed piston 2-stroke axial engine and a 4-stroke axial engine. The opposed piston two stroke also offers an option of a novel cylinder deactivation design. Both, two stroke and four stroke engines share novel systems for coupling piston reciprocation to shaft rotation, piston and piston ring lubricant distribution, and provision for reacting out piston side load with minimum mechanical friction

A water jacket of a cylinder block includes a main passage and a sub-passage. The main passage is formed along the periphery of a cylinder bank, and extends between a plurality of head bolt bosses and the cylinder bank. The sub-passage is formed at a position spaced from the cylinder bank farther than the main passage, to diverge from the main passage at a first position, and join the main passage at a second position downstream of the first position. A first head bolt boss by which coolant flowing from a coolant inlet initially passes is interposed between the main passage and the sub-passage. The first position is located between the first head bolt boss and the coolant inlet. The second position is located between a second head bolt boss by which the coolant passes next, and the first head bolt boss.

An imbalance detection device is provided. An obtainment process includes obtaining a rotation waveform variable based on a detection value of a sensor that detects a rotational behavior of a crankshaft, and an air-fuel ratio detection variable in each of a plurality of first intervals. A calculation process includes calculating an imbalance variable based on an output of a mapping having a value obtained by the obtainment process as an input. The imbalance variable indicates a degree of variations in an air-fuel ratio of the internal combustion engine. The rotation waveform variable indicates a difference between instantaneous speed variables that are variables corresponding to the rotational speed of the crankshaft in each of the second intervals.

An internal combustion engine may include a first piston reciprocatingly disposed in a first cylinder, a combustion chamber fluidly coupled with the first cylinder, and an ignition source at least partially disposed within the combustion chamber. An intake valve may provide selective fluid communication between an intake system and the combustion chamber, and an exhaust valve may provide selective fluid communication between an exhaust system and the combustion chamber. A second piston may be reciprocatingly disposed within a second cylinder. A crankshaft may be coupled with the first piston and the second piston for rotational motion associated with reciprocating movement of the first piston and the second piston.

A Stirling cycle machine. The machine includes at least one rocking drive mechanism which includes: a rocking beam having a rocker pivot, at least one cylinder and at least one piston. The piston is housed within a respective cylinder and is capable of substantially linearly reciprocating within the respective cylinder. Also, the drive mechanism includes at least one coupling assembly having a proximal end and a distal end. The linear motion of the piston is converted to rotary motion of the rocking beam. Also, a crankcase housing the rocking beam and housing a first portion of the coupling assembly is included. The machine also includes a working space housing the at least one cylinder, the at least one piston and a second portion of the coupling assembly. An airlock is included between the workspace and the crankcase and a seal is included for sealing the workspace from the airlock and crankcase. A burner and burner control system is also included for heating the machine and controlling ignition and combustion in the burner.

A Stirling cycle machine. The machine includes at least one rocking drive mechanism which includes: a rocking beam having a rocker pivot, at least one cylinder and at least one piston. The piston is housed within a respective cylinder and is capable of substantially linearly reciprocating within the respective cylinder. Also, the drive mechanism includes at least one coupling assembly having a proximal end and a distal end. The linear motion of the piston is converted to rotary motion of the rocking beam. Also, a crankcase housing the rocking beam and housing a first portion of the coupling assembly is included. The machine also includes a working space housing the at least one cylinder, the at least one piston and a second portion of the coupling assembly. An airlock is included between the workspace and the crankcase and a seal is included for sealing the workspace from the airlock and crankcase. A burner and burner control system is also included for heating the machine and controlling ignition and combustion in the burner.