There is provided a water cooled engine including a cylinder head with minimized thermal strain. A head water jacket includes an inter-exhaust-port-wall water channel between a first exhaust entrance port wall and a second exhaust entrance port wall. A cylinder head includes a cooling water injection passage provided at a bottom wall of the cylinder head. The cooling water injection passage is positioned on the exhaust end side, and includes a passage entrance provided on the exhaust end side, and a passage exit directed toward the inter-exhaust-port-wall water channel. An exhaust port wall includes a heat dissipation fin extending from a first exhaust entrance port wall toward an exhaust end. The space between the heat dissipation fin and a second exhaust entrance port wall forms a water channel entrance of the inter-exhaust-port-wall water channel.

There is provided a water cooled engine including a cylinder head with minimized thermal strain. A head water jacket includes an inter-exhaust-port-wall water channel between a first exhaust entrance port wall and a second exhaust entrance port wall. A cylinder head includes a cooling water injection passage provided at a bottom wall of the cylinder head. The cooling water injection passage is positioned on the exhaust end side, and includes a passage entrance provided on the exhaust end side, and a passage exit directed toward the inter-exhaust-port-wall water channel. An exhaust port wall includes a heat dissipation fin extending from a first exhaust entrance port wall toward an exhaust end. The space between the heat dissipation fin and a second exhaust entrance port wall forms a water channel entrance of the inter-exhaust-port-wall water channel.

A cylinder head in a cylinder head assembly includes an upper deck, a fire deck, gas exchange conduits, and a coolant cavity extending peripherally around the gas exchange conduits. The cylinder head also includes an igniter socket having an igniter post, and a radially outward sleeve step continuously circumferential of an igniter bore center axis. A cooling moat is formed between the igniter post and the sleeve step. The coolant cavity includes a valve bridge through-channel and a valve bridge part-way channel each fluidly connected to the igniter socket to provide coolant flow into and out of the cooling moat passively.

A cylinder head in a cylinder head assembly includes an upper deck, a fire deck, gas exchange conduits, and a coolant cavity extending peripherally around the gas exchange conduits. The cylinder head also includes an igniter socket having an igniter post, and a radially outward sleeve step continuously circumferential of an igniter bore center axis. A cooling moat is formed between the igniter post and the sleeve step. The coolant cavity includes a valve bridge through-channel and a valve bridge part-way channel each fluidly connected to the igniter socket to provide coolant flow into and out of the cooling moat passively.

A heat exchanging member including a hollow pillar shaped honeycomb structure having partition walls defining cells, the cells penetrating from a first end face to a second end face to form flow paths for a first fluid, an inner peripheral wall, and an outer peripheral wall; and a covering member being configured to cover the outer peripheral wall of the pillar shaped honeycomb structure. The heat exchanging member is configured to perform heat exchange between the first fluid and a second fluid flowing through an outer side of the covering member. In the heat exchanging member, in a cross section of the pillar shaped honeycomb structure perpendicular to a flow path direction of the first fluid, the cells are radially provided, and each of the inner peripheral wall and the outer peripheral wall has a thickness larger than that of each of the partition walls.

A heat exchanging member including a hollow pillar shaped honeycomb structure having partition walls defining cells, the cells penetrating from a first end face to a second end face to form flow paths for a first fluid, an inner peripheral wall, and an outer peripheral wall; and a covering member being configured to cover the outer peripheral wall of the pillar shaped honeycomb structure. The heat exchanging member is configured to perform heat exchange between the first fluid and a second fluid flowing through an outer side of the covering member. In the heat exchanging member, in a cross section of the pillar shaped honeycomb structure perpendicular to a flow path direction of the first fluid, the cells are radially provided, and each of the inner peripheral wall and the outer peripheral wall has a thickness larger than that of each of the partition walls.

Methods and systems are provided for adjusting a location of a fuel injection in response to a substitution rate and a desired EGR flow. In one example, a method may include injecting a first fuel to a combustion chamber via a direct injector positioned to inject directly into the combustion chamber, injecting a second, different, fuel to the combustion chamber via an exhaust port injector positioned to inject toward an exhaust valve of the combustion chamber, and combusting the first and second fuels together in the combustion chamber.

Methods and systems are provided for adjusting a location of a fuel injection in response to a substitution rate and a desired EGR flow. In one example, a method may include injecting a first fuel to a combustion chamber via a direct injector positioned to inject directly into the combustion chamber, injecting a second, different, fuel to the combustion chamber via an exhaust port injector positioned to inject toward an exhaust valve of the combustion chamber, and combusting the first and second fuels together in the combustion chamber.

An engine system in which blow-by gas with a specific gravity less than 1 with reference to air is generatable includes a cylinder block. The cylinder block includes a cylinder and a crank chamber which are arranged in an up/down direction, the crank chamber being positioned below the cylinder. An internal peripheral face of the cylinder block has a ventilation port that connects to a ventilation passage that connects an internal space of the crank chamber with an external space out of the cylinder block, and that is open. The ventilation port is placed above a center in the up/down direction in the crank chamber.

An engine system in which blow-by gas with a specific gravity less than 1 with reference to air is generatable includes a cylinder block. The cylinder block includes a cylinder and a crank chamber which are arranged in an up/down direction, the crank chamber being positioned below the cylinder. An internal peripheral face of the cylinder block has a ventilation port that connects to a ventilation passage that connects an internal space of the crank chamber with an external space out of the cylinder block, and that is open. The ventilation port is placed above a center in the up/down direction in the crank chamber.