An engine includes an exhaust manifold, an intake manifold, and an EGR device configured to supply EGR gas from the exhaust manifold to the intake manifold. A longitudinal direction of the EGR cooler is in an up-down direction of the engine in a used state. The exhaust manifold has an EGR pipe that is connected to an EGR cooler, and a part of the EGR pipe extends in left-and-right directions. The part of the EGR pipe is provided at a side where a flywheel housing is provided. An upper end of the EGR cooler has a supply port into which the EGR gas is supplied from the exhaust manifold. The part of the EGR pipe and the flywheel housing are located in an up-down directions.

An engine includes an exhaust manifold, an intake manifold, and an EGR device configured to supply EGR gas from the exhaust manifold to the intake manifold. A longitudinal direction of the EGR cooler is in an up-down direction of the engine in a used state. The exhaust manifold has an EGR pipe that is connected to an EGR cooler, and a part of the EGR pipe extends in left-and-right directions. The part of the EGR pipe is provided at a side where a flywheel housing is provided. An upper end of the EGR cooler has a supply port into which the EGR gas is supplied from the exhaust manifold. The part of the EGR pipe and the flywheel housing are located in an up-down directions.

A fuel injection system for a spark-ignition internal combustion engine having a number of cylinders, where a plurality of respective main combustion chambers are defined; a number of first injectors and spark plugs coupled to the cylinders; a number of combustion pre-chambers, each obtained in the area of a respective spark plug; a number of extraction ducts, which originate from a respective cylinder to extract the gas mixture present inside the respective main combustion chamber; a reserve, where the gases extracted by the extraction ducts are mixed with the quantity of fuel needed to obtain a combustion under stoichiometric conditions inside the combustion pre-chambers; and a number of second injectors, each coupled to a respective combustion pre-chamber, into which it injects the gas-and-fuel mixture coming from the reserve.

An EGR cooler 5 is attached to an engine 1 via a bracket 6. The bracket 6 has an exhaust introduction path 65 for introducing some exhaust discharged from a cylinder head 11 to the EGR cooler 5, an exhaust recirculation path 66 for recirculating exhaust that has passed through the EGR cooler 5 toward the engine 1, a cooling water introduction path 67 for introducing cooling water from cooling water supply parts (3, 13-15) to the EGR cooler 5, and a cooling water recirculation path 68 for recirculating cooling water that has passed through the EGR cooler 5 to the cooling water supply parts.

An EGR cooler 5 is attached to an engine 1 via a bracket 6. The bracket 6 has an exhaust introduction path 65 for introducing some exhaust discharged from a cylinder head 11 to the EGR cooler 5, an exhaust recirculation path 66 for recirculating exhaust that has passed through the EGR cooler 5 toward the engine 1, a cooling water introduction path 67 for introducing cooling water from cooling water supply parts (3, 13-15) to the EGR cooler 5, and a cooling water recirculation path 68 for recirculating cooling water that has passed through the EGR cooler 5 to the cooling water supply parts.

An engine includes an exhaust manifold, an intake manifold, and an EGR device configured to supply EGR gas from the exhaust manifold to the intake manifold. An EGR cooler is provided at a side of the exhaust manifold, and a longitudinal direction of the EGR cooler is in an up-down direction of the engine in a used state.

An engine includes an exhaust manifold, an intake manifold, and an EGR device configured to supply EGR gas from the exhaust manifold to the intake manifold. An EGR cooler is provided at a side of the exhaust manifold, and a longitudinal direction of the EGR cooler is in an up-down direction of the engine in a used state.

A cylinder head includes: an exhaust port configured to lead out exhaust gas from combustion chamber; an intake port configured to introduce fresh air into the combustion chamber; and an EGR gas passage in which EGR gas flows, wherein exhaust outlets of the exhaust port and an EGR gas inlet of the second EGR pipe are located on a first side of the cylinder head and, and a fresh air inlet communicated to the intake port and an EGR gas outlet of the EGR gas passage are located on a second side which is opposite from the first side.

A cylinder head includes: an exhaust port configured to lead out exhaust gas from combustion chamber; an intake port configured to introduce fresh air into the combustion chamber; and an EGR gas passage in which EGR gas flows, wherein exhaust outlets of the exhaust port and an EGR gas inlet of the second EGR pipe are located on a first side of the cylinder head and, and a fresh air inlet communicated to the intake port and an EGR gas outlet of the EGR gas passage are located on a second side which is opposite from the first side.

An engine system includes main exhaust ports fluidly communicating with each combustion chamber. An exhaust variable valve lift apparatus controls an operation of a main exhaust valve which closes or opens each main exhaust port. A main exhaust manifold is connected with the main exhaust ports. Scavenge exhaust ports fluidly communicate with each combustion chamber. A variable scavenge apparatus controls an operation of a scavenge valve which closes and opens each scavenge exhaust port. A scavenge manifold is connected with the scavenge exhaust ports. A controller is configured to control operations of the exhaust variable valve lift apparatus and the variable scavenge apparatus according to a vehicle operation state.