Abstract: 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.

Abstract: 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.

Abstract: A boosted engine is provided, which includes a first turbocharger having a first compressor and a first turbine, a second turbocharger having a second compressor and a second turbine, and first and second exhaust emission control devices. The engine has a first exhaust port which opens at a first timing, and a second exhaust port which is in parallel with the first exhaust port and opens at a second timing later than the first timing. The exhaust passage has a first exhaust passage connected to the first exhaust port and a second exhaust passage connected to the second exhaust port. The first turbine and the first exhaust emission control device are disposed in the first exhaust passage in this order from upstream to downstream, and the second exhaust emission control device and the second turbine are disposed in the second exhaust passage in this order from upstream to downstream.

Abstract: An engine with a boosting system is provided, which includes a turbocharger including a compressor provided in an intake passage of the engine and configured to boost intake air to be supplied to the engine, and a turbine provided in an exhaust passage of the engine. The engine includes an electric supercharger provided in the intake passage downstream of the compressor and configured to operate when the engine operates in a low-speed range, an emission control device provided in the exhaust passage upstream of the turbine and configured to purify exhaust gas discharged from the engine, and an EGR system having a passage connecting a part of the intake passage between the compressor and the electric supercharger to a part of the exhaust passage between the emission control device and the turbine, and configured to recirculate a part of the exhaust gas to the intake passage as EGR gas.

Abstract: An engine includes: a turbocharger including a turbine and a compressor; an EGR passage connecting an exhaust passage on an upstream side of the turbine and an air intake passage on a downstream side of the compressor; an EGR valve provided in the EGR passage; a bypass passage that bypasses the turbine; and a waste gate valve provided in the bypass passage. In the engine, when a boost pressure is increased to a limit pressure, a first boost pressure control is executed, in which the EGR valve is opened and the waste gate valve is closed. After the first boost pressure control starts, when an engine speed is increased to a prescribed value, a second boost pressure control is executed, in which the waste gate valve is opened in addition to the EGR valve.

Abstract: An engine includes: a turbocharger including a turbine and a compressor; an EGR passage connecting an exhaust passage on an upstream side of the turbine and an air intake passage on a downstream side of the compressor; an EGR valve provided in the EGR passage; a bypass passage that bypasses the turbine; and a waste gate valve provided in the bypass passage. In the engine, when a boost pressure is increased to a limit pressure, a first boost pressure control is executed, in which the EGR valve is opened and the waste gate valve is closed. After the first boost pressure control starts, when an engine speed is increased to a prescribed value, a second boost pressure control is executed, in which the waste gate valve is opened in addition to the EGR valve.

Abstract: A compression self-ignition engine is provided. The engine includes an engine body and an intake passage, and CI combustion is performable in a part of an engine operating range. The intake passage includes a high-temperature passage provided with a heater for heating intake air, a low-temperature passage provided with a cooler for cooling the intake air, a manifold section where the high-temperature and low-temperature passages merge together, and a downstream passage connecting the manifold section with the engine body. A throttle valve for adjusting a flow rate of the intake air is provided in each of the high-temperature and low-temperature passages. At least in an engine operating range where the CI combustion is performed, openings of the throttle valves are controlled to bring a temperature of the intake air within the manifold section into a predetermined temperature range, based on temperature conditions of the heater and the cooler, respectively.

Abstract: A four-cylinder engine has a valve overlap period during which an exhaust valve and an intake valve of each cylinder are both opened. Cylinder pipes for cylinders having adjacent ignition timings of the engine are connected to a turbo charger, and cylinder pipes for cylinders having adjacent ignition timings are connected to another turbo charger. Accordingly, a properly great supercharging pressure can be obtained in a low engine-speed area.

Abstract: Provided is an exhaust system of a multi-cylinder engine capable of increasing the air-intake and thereby increasing the engine output with a simple configuration. The exhaust system is provided with low velocity-side passages 54, high velocity-side passages 53, a low velocity-side collection part 56, a high velocity-side collection part 57, and a flow passage area variable valve 58 capable of changing the flow passage area of the respective high velocity-side passages 53.

Abstract: A valve overlap period is increased as a desired torque of an engine increases by advancing an opening timing of an intake valve at a rate greater than that of retarding a closing timing of an exhaust valve in a low engine-torque area in which the desired torque of the internal combustion engine is relatively low (step S16). The valve overlap period is increased as the desired torque of the engine increases by retarding the closing timing of the exhaust valve at a rate greater than that of advancing the opening timing of the intake valve in a high engine-torque area in which the desired torque of the internal combustion engine is relatively high (step S17). Accordingly, the drivability can be improved by obtaining the proper torque and the smooth torque curve in the wide driving area.

Abstract: Three or more independent passages are coupled to respective cylinders which are different from each other, and a collective portion where the independent passages collect is provided. An exhaust turbocharger is arranged downstream of the collective portion. Rotary throttle valves are arranged respectively in the independent passages upstream of the collective portion. At least two of the throttle valves are supported by a common rotary axis. The independent passages with the throttle valves supported by the common rotary axis are coupled to cylinders which have exhaust strokes which are not adjacent to each other. Accordingly, the exhaust gas can be supplied to the exhaust turbocharger efficiently.

Abstract: An engine system with a turbocharger is provided. The system may include an exhaust manifold having plural independent exhaust passages, each of the exhaust passages being connected to an exhaust port of a corresponding engine cylinder. The system may further include a collective part formed by gathering said independent exhaust passages in said exhaust manifold or on a downstream side of said exhaust manifold. The system may further include an exhaust turbocharger connected to a downstream side of said collective part. The system may further include a variable exhaust valve for changing each passage cross-sectional area of said independent exhaust passage at an upstream side of said collective part. The system may further include a controller for controlling said variable exhaust valve, wherein said controller is configured to perform independent exhaust throttle control for reducing a passage cross-sectional area of at least one of said independent exhaust passages.

Abstract: Provided is an exhaust system of a multi-cylinder engine capable of increasing the air-intake and thereby increasing the engine output with a simple configuration. The exhaust system is provided with low velocity-side passages 54, high velocity-side passages 53, a low velocity-side collection part 56, a high velocity-side collection part 57, and a flow passage area variable valve 58 capable of changing the flow passage area of the respective high velocity-side passages 53.

Abstract: A four-cylinder engine has a valve overlap period during which an exhaust valve and an intake valve of each cylinder are both opened. Cylinder pipes for cylinders having adjacent ignition timings of the engine are connected to a turbo charger, and cylinder pipes for cylinders having adjacent ignition timings are connected to another turbo charger. Accordingly, a properly great supercharging pressure can be obtained in a low engine-speed area.

Abstract: A valve overlap period is increased as a desired torque of an engine increases by advancing an opening timing of an intake valve at a rate greater than that of retarding a closing timing of an exhaust valve in a low engine-torque area in which the desired torque of the internal combustion engine is relatively low (step S16). The valve overlap period is increased as the desired torque of the engine increases by retarding the closing timing of the exhaust valve at a rate greater than that of advancing the opening timing of the intake valve in a high engine-torque area in which the desired torque of the internal combustion engine is relatively high (step S17). Accordingly, the drivability can be improved by obtaining the proper torque and the smooth torque curve in the wide driving area.

Abstract: Three or more independent passages are coupled to respective cylinders which are different from each other, and a collective portion where the independent passages collect is provided. An exhaust turbocharger is arranged downstream of the collective portion. Rotary throttle valves are arranged respectively in the independent passages upstream of the collective portion. At least two of the throttle valves are supported by a common rotary axis. The independent passages with the throttle valves supported by the common rotary axis are coupled to cylinders which have exhaust strokes which are not adjacent to each other. Accordingly, the exhaust gas can be supplied to the exhaust turbocharger efficiently.

Abstract: There is provided a method of controlling an engine system. The engine system comprises an internal combustion engine, a supercharging system having at least one supercharger to boost intake air to the internal combustion engine, a turbine, and a motor. The turbine receives an exhaust gas flow from an exhaust system of the internal combustion engine and is capable of at least partly driving the supercharging system. The motor is capable of at least partly driving the supercharging system.

Abstract: There is provided a method for controlling an electrically driven supercharger of an internal combustion engine. The method comprises operating the supercharger at a first speed during a first engine operating condition. The method further comprises operating the supercharger at a second speed during a second engine operating condition, the second speed being lower than the first speed and increasing as the capacity of the electric power source decreases. According to the method, during a transition from the second engine operating condition to the first engine operating condition, the speed of the supercharger is increased from the second speed to the first speed. At that time, the second speed is increased as the capacity of the electric power source decreases, and as a result, the supercharger speed increase that results from the transition may become smaller.

Abstract: An engine system with a turbocharger is provided. The system may include an exhaust manifold having plural independent exhaust passages, each of the exhaust passages being connected to an exhaust port of a corresponding engine cylinder. The system may further include a collective part formed by gathering said independent exhaust passages in said exhaust manifold or on a downstream side of said exhaust manifold. The system may further include an exhaust turbocharger connected to a downstream side of said collective part. The system may further include a variable exhaust valve for changing each passage cross-sectional area of said independent exhaust passage at an upstream side of said collective part. The system may further include a controller for controlling said variable exhaust valve, wherein said controller is configured to perform independent exhaust throttle control for reducing a passage cross-sectional area of at least one of said independent exhaust passages.

Abstract: There is provided a method of controlling an engine system. The engine system comprises an internal combustion engine, a supercharging system having at least one supercharger to boost intake air to the internal combustion engine, a turbine, and a motor. The turbine receives an exhaust gas flow from an exhaust system of the internal combustion engine and is capable of at least partly driving the supercharging system. The motor is capable of at least partly driving the supercharging system.