The invention is provided with an ignition control section and an injection control section. When partial compression ignition combustion is carried out, the ignition control section causes an ignition plug to carry out: main ignition in which a spark is generated in a late period of a compression stroke or an initial period of an expansion stroke to initiate SI combustion; and preceding ignition in which the spark is generated at earlier timing than the main ignition. Also, when the partial compression ignition combustion is carried out, the injection control section causes an injector to inject fuel at such timing that the fuel exists in a cylinder at an earlier time point than the preceding ignition. Timing of the preceding ignition is more advanced when a swirl flow is gentle than when the swirl flow is strong.

A utility vehicle comprising a frame, a body supported by the frame, a seating area supported by the frame, front and rear ground engaging members supporting the frame and the body, and a powertrain drivingly coupled to the front and rear ground engaging members, the powertrain including an engine having a cylinder block having a plurality of cylinders, a cylinder head removably coupled to the cylinder block, a crankcase having a first portion and a second portion, the first portion of the crankcase being removably coupled to the cylinder block, and at least one gasket positioned between the cylinder block and the first portion of the crankcase, the at least one gasket configured to individually seal each of the plurality of cylinders relative to the first portion of the crankcase.

A utility vehicle comprising a frame, a body supported by the frame, a seating area supported by the frame, front and rear ground engaging members supporting the frame and the body, and a powertrain drivingly coupled to the front and rear ground engaging members, the powertrain including an engine having a cylinder block having a plurality of cylinders, a cylinder head removably coupled to the cylinder block, a crankcase having a first portion and a second portion, the first portion of the crankcase being removably coupled to the cylinder block, and at least one gasket positioned between the cylinder block and the first portion of the crankcase, the at least one gasket configured to individually seal each of the plurality of cylinders relative to the first portion of the crankcase.

A utility vehicle comprising a frame, a body supported by the frame, a seating area supported by the frame, front and rear ground engaging members supporting the frame and the body, and a powertrain drivingly coupled to the front and rear ground engaging members, the powertrain including an engine having a cylinder block having a plurality of cylinders, a cylinder head removably coupled to the cylinder block, a crankcase having a first portion and a second portion, the first portion of the crankcase being removably coupled to the cylinder block, and at least one gasket positioned between the cylinder block and the first portion of the crankcase, the at least one gasket configured to individually seal each of the plurality of cylinders relative to the first portion of the crankcase.

A utility vehicle comprising a frame, a body supported by the frame, a seating area supported by the frame, front and rear ground engaging members supporting the frame and the body, and a powertrain drivingly coupled to the front and rear ground engaging members, the powertrain including an engine having a cylinder block having a plurality of cylinders, a cylinder head removably coupled to the cylinder block, a crankcase having a first portion and a second portion, the first portion of the crankcase being removably coupled to the cylinder block, and at least one gasket positioned between the cylinder block and the first portion of the crankcase, the at least one gasket configured to individually seal each of the plurality of cylinders relative to the first portion of the crankcase.

A piston discharge structure for a plasma cloud excitation engine is provided. The piston discharge structure includes a movement electrode, a distributed multi-cavity combustion chamber, a fixed electrode, and a variable interval discharge region. The movement electrode is provided at a top portion of a piston and includes a first combination shape and a first movement electrode structure, the distributed multi-cavity combustion chamber is provided at the top portion of the piston, the fixed electrode is provided at a top portion of a cylinder block or a bottom portion of a cylinder head and including a second combination shape and a second structure, and the variable interval discharge region is defined by the movement electrode and the fixed electrode.

A control device is provided for a compression ignition engine, which controls so that partial compression ignition combustion of A/F-lean mixture gas is carried out in a specific range where an engine load is low. In a first range of the specific range, a normal ignition in which sparks are generated in a late period of compression stroke or an early period of expansion stroke to start SI combustion, and a preceding ignition in which sparks are generated at a timing included in intake stroke or compression stroke and earlier than the normal ignition by a given amount or more are performed, and fuel is injected at a timing where fuel is present before the preceding ignition inside the combustion chamber. In a high-load side second range of the specific range, at least the normal ignition is performed and the execution of the preceding ignition is limited.

A control device is provided for a compression ignition engine, which controls so that partial compression ignition combustion of A/F-lean mixture gas is carried out in a specific range where an engine load is low. In a first range of the specific range, a normal ignition in which sparks are generated in a late period of compression stroke or an early period of expansion stroke to start SI combustion, and a preceding ignition in which sparks are generated at a timing included in intake stroke or compression stroke and earlier than the normal ignition by a given amount or more are performed, and fuel is injected at a timing where fuel is present before the preceding ignition inside the combustion chamber. In a high-load side second range of the specific range, at least the normal ignition is performed and the execution of the preceding ignition is limited.

An air-fuel ratio control device sets a target air-fuel ratio and performs an air-fuel ratio control based on the target air-fuel ratio for an engine of a spark ignition type. The air-fuel ratio control device includes a lean combustion determination unit that determines whether a lean combustion is performed in the engine at the target air-fuel ratio, the target air-fuel ratio being set leaner than the theoretical air-fuel ratio; a target NOx setting unit that sets a target NOx concentration according to an operation state of the engine; an acquisition unit that acquires an actual NOx concentration detected by using a NOx concentration detection unit in an exhaust passage of the engine; and a correction unit that corrects the target air-fuel ratio based on the target NOx concentration and the actual NOx concentration when determination is made that lean combustion is performed.

The magnetic valve recoil device is intended for a valve-type ignition pre-chamber having a stratification cavity connected by a stratification pipe, which a stratification valve can close, to a combustion chamber housing a primary charge, a stratification injector, and an ignition unit leading to the cavity in order to inject and ignite an initiator charge so as to ignite the primary charge via a torch ignition pre-chamber formed by the stratification valve with the stratification pipe when it is not closing the latter, the valve being otherwise kept in contact with the pipe by a magnetic field created by a magnetic field source.