Mazda Motor Corporation

Naoyuki Yamagata

Noriyuki Iwata

Toshimitsu Tanaka

Mitsuo Hitomi

Toshihiko Hattori

Mikihito Fujii

Kenji Kashiyama

Tatsuya Uesugi

Kazumasa Nomura

Taiji Matsubara

Junsou Sasaki

Shunji Masuda

Susumu Masuyama

Hiroyuki Oda

Yoshihisa Nou

Masashi Marubara

Akira Kageyama

Yoshihisa Nakamoto

Kazuya Yokota

Shuhei Tsujita

Kazuaki Narahara

Kazuhiko Hashimoto

Takeshi Nagasawa

Tadayoshi Kaide

Osamu Aoki

Masaharu Marumoto

Kazuaki Umezawa

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.

Two-stroke engine with supercharger

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.

Turbocharged engine

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.

Engine with supercharger

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, high velocity-side passages, a low velocity-side collection part, a high velocity-side collection part, and a flow passage area variable valvecapable of changing the flow passage area of the respective high velocity-side passages. The relationship of a diameter aof a true circle with a same area as the flow passage area of the downstream end of the low velocity-side passages, a diameter Dof a true circle with a same area as the flow passage area of the downstream end of the low velocity-side collection part, a diameter aof a true circle with a same area as the flow passage area of the downstream end of the high velocity-side passages, and a diameter Dof a true circle with a same area as the flow passage area of the downstream end of the high velocity-side collection partis made to be a/D&#x2267;a/D. In a low velocity region R, an exhaust valveis opened during the overlap period of an intake valveand the exhaust valveand the flow passage area of the high velocity-side passagesis narrowed, and, in a high velocity region R, the flow passage area of the high velocity-side passagesis set to be a maximum area.

Exhaust system of multi-cylinder engine

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 S). 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 S). Accordingly, the drivability can be improved by obtaining the proper torque and the smooth torque curve in the wide driving area.

Method of controlling engine system and engine system

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.

Exhaust passage structure of multi-cylinder engine

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.

Supercharger for an engine

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. The method comprises operating the exhaust system in a first exhaust state and operating the motor in a first motor state when a speed of the internal combustion engine is below a first engine speed, operating the exhaust system in the first exhaust state and operating the motor in a second motor state where power to drive the motor is reduced from that in the first motor state when the speed of the internal combustion engine is between the first engine speed and a second engine speed which greater the said first engine speed, and operating the exhaust system in a second exhaust state where energy transmitted from the internal combustion engine to the turbine is reduced from that in the first exhaust state and operating the motor in the second motor state when the speed of the internal combustion engine is above the second engine speed. Accordingly, the maximum torque can be increased while maintaining the system efficiency over the entire engine speed range.

Control of supercharged engine

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. Consequently, the inrush electric current from the electric power source to the electric motor may be reduced during the transition, thereby avoiding further degradation of the electric power source.

Control for electrically driven supercharger

A novel mounting for a supercharger in a V-type engine is provided such that the supercharger is mounted in a space between the cylinder banks of a V-type engine. The mounting structure of the intake manifold suspends the supercharger, and the lower portion of the supercharger positions the supercharger with respect to the engine block.

V-type engine with supercharger mounting

A drive system for driving an engine auxiliary equipment has a first power transfer device for transferring an output torque of the crankshaft to an interim shaft at all time and a second power transfer device comprising a crank pulley mounted for relative rotation on the crankshaft, an interim pulley mounted for relative rotation on the interim shaft and an input pulley related to the auxiliary equipment all of which pulleys are operationally coupled by a belt so as to transfer an output torque of the crankshaft to the auxiliary equipment. A first clutch is disposed between the crankshaft and crank pulley so as to connect and disconnect a transfer of power between the crankshaft and crank pulley. A second clutch is disposed between the interim shaft and interim pulley so as to connect and disconnect a transfer of power between the interim shaft and interim pulley. The first and second clutches are actuated to create a first transfer path or a second transfer path which are different in ratio of power transfer.

Auxiliary equipment drive system

The supercharged internal combustion engine is so adapted as to set the air-fuel ratio to become a lean air-fuel ratio which is leaner than stoichiometric and lean enough to maximize improvements in a rate of consumption of fuel, for example, to the A/F ratio of 16, when the supercharger exists in such a supercharging region as demonstrating its sufficient degree of supercharging capability. When the air-fuel ratio is made lean in the supercharging region, exhaust gases are recirculated into the intake system of the engine, in addition to a mixed fuel. Preferably, the exhaust gases having lower temperatures are recirculated at the time of a high load of the engine in the supercharging region, while the exhaust gases having higher temperatures are recirculated at the time of a low load of the engine therein.

Supercharged internal combustion engine

An apparatus for driving devices which are operated by, or 'supplementary' to, a V-type internal combustion engine, having a crankshaft and overhead camshafts, includes a camshaft drive mechanism for rotatably connecting the camshafts to the crankshaft so that the camshafts are 'timely' driven. A supplementary device drive mechanism rotatably connects supplementary devices independently of the overhead camshafts to the crankshaft. The crankshaft is provided with a transmission gear train for transmitting rotation of the camshafts to the camshaft drive mechanism and the supplementary device drive mechanism.

Apparatus for driving various devices by internal combustion engine

The support structure for cam shafts including an intake cam shaft and an exhaust cam shaft, a pair of intake cams per a cylinder formed side by side on the intake cam shaft, a pair of exhaust cams per a cylinder formed side by side on the exhaust cam shaft and having longer interval therebetween than that of the intake cams, a cam cap forming an upper portion of the support structure for the cam shafts and an upper wall portion of a plug hole for inserting the ignition plug, a cam carrier forming a lower portion of the support structure for the cam shafts and a lower wall portion of the plug hole, and fasteners for fastening the cam cap to an engine block. The fasteners are disposed both at longitudinally opposite sides of the pair of intake cams and between the pair of the exhaust cams.

Support structure for cam shafts

An engine with a row of cylinders is provided with two intake ports and intake valves and two exhaust ports and exhaust valves for each cylinder. The intake ports are arranged on one side of a center line of the row of cylinders, adjacent to each other, and side by side in a direction parallel to the cylinder row. The exhaust ports are arranged on another side of the center line, adjacent to each other, and side by side in the direction parallel to the cylinder row so that their centers are located at a distance apart which is larger than a distance at which centers of the intake ports are separated. The cylinder is formed with a 'squish' surface between the exhaust ports which provides a squish area between the cylinder head and piston. This produces a squish or compressed flow of the air-fuel mixture to the exhaust ports in the combustion chamber.

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Hiroshima, Japan

Naoyuki Yamagata