Abstract: A cooling device of an outboard engine unit includes a cooling water passage for delivering cooling water from a water pump. The cooling water passage branches into a first passageway for cooling a cylinder block and cylinder head of an engine and a second passageway for cooling a case of a supercharger. Thus, the supercharger and the engine can be cooled to and kept at their respective appropriate temperatures.

Abstract: A cooling device of an outboard engine unit includes a cooling water passage for delivering cooling water from a water pump. The cooling water passage branches into a first passageway for cooling a cylinder block and cylinder head of an engine and a second passageway for cooling a case of a supercharger. Thus, the supercharger and the engine can be cooled to and kept at their respective appropriate temperatures.

Abstract: An ignition control system which reduces decrease in output of the internal combustion engine and increase in exhaust gas temperature when one spark plug alone is used for ignition is provided. The ignition control system is used for an engine having cylinders, each of which has two spark plugs. The ignition control system includes a first controller having a first ignition timing control section for controlling ignition timing of a first group of spark plugs including a first spark plug of the two spark plugs in each cylinder and a second controller having a second ignition timing control section for controlling ignition timing of a second group of spark plugs including a second spark plug of the two spark plugs in each cylinder. The first and second ignition timing control sections correct ignition timing according to predetermined parameters when one of the two spark plugs is not used in at least one cylinder.

Abstract: A Rankine cycle system includes a first Rankine cycle (2A) operated by a first working medium and a second Rankine cycle (2B) operated by a second working medium. The first Rankine cycle (2A) is constituted from an evaporator (3A), an expander (4), a condenser (5A) and a supply pump (6A), and the second Rankine cycle (2B) is constituted from an evaporator (3B), the expander (4), a condenser (5B) and a supply pump (6c). The evaporator (3A) in the first Rankine cycle (2A) and the evaporator (3B) in the second Rankine cycle (2B) are disposed at locations upstream and downstream of an exhaust emission control device (8) mounted in an exhaust passage (7) for the internal combustion engine (1). The first working medium has a boiling point higher than that of the second working medium, and the capacity of the pump (6A) in at least the first Rankine cycle (2A) is variable.

Abstract: A Rankine cycle system includes a first Rankine cycle (2A) operated by a first working medium and a second Rankine cycle (2B) operated by a second working medium. The first Rankine cycle (2A) is constituted from an evaporator (3A), an expander (4), a condenser (5A) and a supply pump (6A), and the second Rankine cycle (2B) is constituted from an evaporator (3B), the expander (4), a condenser (5B) and a supply pump (6c). The evaporator (3A) in the first Rankine cycle (2A) and the evaporator (3B) in the second Rankine cycle (2B) are disposed at locations upstream and downstream of an exhaust emission control device (8) mounted in an exhaust passage (7) for the internal combustion engine (1). The first working medium has a boiling point higher than that of the second working medium, and the capacity of the pump (6A) in at least the first Rankine cycle (2A) is variable.

Abstract: A gas jacket is provided in a lower portion of a cylinder block, so that an exhaust gas in an exhaust gas passage is supplied to the gas jacket through an exhaust gas supply passage having an exhaust gas supply valve. Fresh air in an intake passage is supplied to an intake passage through a fresh-air supply passage having a fresh-air supply valve. The temperature of a lower cylinder wall is controlled in a feedback manner to a target temperature for the lower cylinder wall. The target temperature for the lower cylinder wall is set at a sufficiently high temperature in a range in which an oil film of lubricating oil, extending from an intermediate portion of the cylinder wall to a bottom dead center of a piston, can be ensured. Therefore, the viscosity of the lubricating oil can be decreased to minimize the friction loss at slide portions of the cylinder wall and the piston, thereby providing an increase in engine output, a reduction in amount of fuel consumed and a reduction in lubricating oil consumed.

Abstract: An intake system for an internal combustion engine includes first and second intake valve bores provided to face a combustion chamber and to be independently opened and closed by first and second intake valves, and first and second intake ports which are connected to the corresponding intake valve bores with a partition wall interposed therebetween and which communicate with a common intake passage. In a particular operation range of the engine, an imbalance is produced in the concentration of the air-fuel mixture flowing through the first and second intake valve bores into the combustion chamber on the basis of a difference between the amounts of fresh air flowing into the first and second intake ports. The intake system further includes a communication hole provided in the partition wall for putting the first and second intake ports into communication with each other. This provides for improvements in the lean combustibility and in the nature of the exhaust gas.

Abstract: In a cooling system for a multi-cylinder engine, a main gallery is provided around outer peripheral portions of the plurality of cylinder bores upstream a block-side coolant jacket to commonly surround the cylinder bores, and an upstream coolant gallery is provided between the block-side coolant jacket and the main coolant gallery to separately surround each of outer peripheries of the cylinder bores. The upstream coolant gallery and the main coolant gallery is in communication with each other through a constriction communication passage provided around the outer periphery of each of the cylinder bores, and the upstream coolant gallery is further in communication with an upstream end of the block-side coolant jacket.