A control apparatus for a compression-ignition type engine is applied to an engine capable of carrying out partial compression ignition combustion in which an air-fuel mixture is subjected to CI combustion by self-ignition. The control apparatus creates a lean A/F environment where an air-fuel ratio as a ratio between air and fuel in a cylinder exceeds 20 and is lower than 35, or a lean G/F environment where a gas air-fuel ratio as a ratio between entire gas and the fuel in the cylinder exceeds 18 and is lower than 50 and the air-fuel ratio substantially matches a stoichiometric air-fuel ratio. Prior to planned timing of the CI combustion, in the lean A/F environment or the lean G/F environment, the control apparatus causes an ignition plug to generate a spark and to generate a high-temperature portion.

A control apparatus for a compression-ignition type engine is applied to an engine capable of carrying out partial compression ignition combustion in which an air-fuel mixture is subjected to CI combustion by self-ignition. The control apparatus creates a lean A/F environment where an air-fuel ratio as a ratio between air and fuel in a cylinder exceeds 20 and is lower than 35, or a lean G/F environment where a gas air-fuel ratio as a ratio between entire gas and the fuel in the cylinder exceeds 18 and is lower than 50 and the air-fuel ratio substantially matches a stoichiometric air-fuel ratio. Prior to planned timing of the CI combustion, in the lean A/F environment or the lean G/F environment, the control apparatus causes an ignition plug to generate a spark and to generate a high-temperature portion.

A two-stroke engine with a supercharger is provided that can prevent occurrence of abnormal combustion under high load and can improve fuel efficiency when compression self-ignition combustion is carried out under low load, and spark ignition combustion is carried out under high load. When an operation state of an engine body is in a high-load side operation range, an intake variable valve mechanism and an exhaust variable valve mechanism are actuated to retard at least closing timing of an intake valve and at least opening timing of an exhaust valve from those in the case where the operation state of the engine body is in a low-load side operation range at the same engine speed as the engine speed detected by engine speed detection means while particular conditions are satisfied.

A two-stroke engine with a supercharger is provided that can prevent occurrence of abnormal combustion under high load and can improve fuel efficiency when compression self-ignition combustion is carried out under low load, and spark ignition combustion is carried out under high load. When an operation state of an engine body is in a high-load side operation range, an intake variable valve mechanism and an exhaust variable valve mechanism are actuated to retard at least closing timing of an intake valve and at least opening timing of an exhaust valve from those in the case where the operation state of the engine body is in a low-load side operation range at the same engine speed as the engine speed detected by engine speed detection means while particular conditions are satisfied.

A two-stroke engine with a supercharger is provided that can prevent occurrence of abnormal combustion under high load and can improve fuel efficiency when compression self-ignition combustion is carried out under low load, and spark ignition combustion is carried out under high load. When an operation state of an engine body is in a high-load side operation range, an intake variable valve mechanism and an exhaust variable valve mechanism are actuated to retard at least closing timing of an intake valve and at least opening timing of an exhaust valve from those in the case where the operation state of the engine body is in a low-load side operation range at the same engine speed as the engine speed detected by engine speed detection means while particular conditions are satisfied.

A two-stroke engine with a supercharger is provided that can prevent occurrence of abnormal combustion under high load and can improve fuel efficiency when compression self-ignition combustion is carried out under low load, and spark ignition combustion is carried out under high load. When an operation state of an engine body is in a high-load side operation range, an intake variable valve mechanism and an exhaust variable valve mechanism are actuated to retard at least closing timing of an intake valve and at least opening timing of an exhaust valve from those in the case where the operation state of the engine body is in a low-load side operation range at the same engine speed as the engine speed detected by engine speed detection means while particular conditions are satisfied.

An internal combustion engine having two “banks” of cylinders, the “banks” being defined by cross-connection to different turbochargers. The exhaust from one bank of cylinders goes to a first turbocharger, and the exhaust from the other bank of cylinders goes to a second turbocharger. However, the compressed air delivered from the turbochargers is cross-connected to the cylinder banks. This allows a cylinder bank to be boosted with a turbocharger whose compressed air output does not necessarily match the exhaust energy of that cylinder bank.

An internal combustion engine having two “banks” of cylinders, the “banks” being defined by cross-connection to different turbochargers. The exhaust from one bank of cylinders goes to a first turbocharger, and the exhaust from the other bank of cylinders goes to a second turbocharger. However, the compressed air delivered from the turbochargers is cross-connected to the cylinder banks. This allows a cylinder bank to be boosted with a turbocharger whose compressed air output does not necessarily match the exhaust energy of that cylinder bank.

An intake-air temperature controlling device for an engine is provided, which includes an engine body, an intake passage, an air intake part, an intake air temperature adjuster configured to adjust air temperature taken in through the air intake part to the passage, and a controller. An operating range in which the CI combustion is performed has a lean operating range in which A/F of mixture gas formed inside the cylinder, or G/F that is a relationship between the total weight G of gas inside the cylinder and a weight F of fuel fed to the cylinder is relatively low, and a rich operating range in which the A/F or G/F is relatively high. When the engine is in the lean operating range, the controller outputs a control signal to the intake air temperature adjuster so that the air temperature is increased, as compared in the rich operating range.

An intake-air temperature controlling device for an engine is provided, which includes an engine body, an intake passage, an air intake part, an intake air temperature adjuster configured to adjust air temperature taken in through the air intake part to the passage, and a controller. An operating range in which the CI combustion is performed has a lean operating range in which A/F of mixture gas formed inside the cylinder, or G/F that is a relationship between the total weight G of gas inside the cylinder and a weight F of fuel fed to the cylinder is relatively low, and a rich operating range in which the A/F or G/F is relatively high. When the engine is in the lean operating range, the controller outputs a control signal to the intake air temperature adjuster so that the air temperature is increased, as compared in the rich operating range.