Abstract: A variable exhaust resonance chamber valve system for internal combustion engine. The engine includes a cylinder having an exhaust port with an axial extent along the axis of the cylinder structure. An exhaust passage having a resonance port extends from the exhaust port to exhaust the engine. A resonance chamber extends from the resonance port and communicates with the exhaust passage through the resonance port. A port valve is adjustable between a second position, in which the port valve exposes the exhaust port throughout its axial extent and occludes the resonance port, and a first position, in which the port valve restricts the axial extent of the exhaust port and exposes the resonance port. A valve control module is connected to the port valve and functions to adjust the port valve between first and second positions in response to engine conditions. At low speeds and low output conditions, the valve is in its first position.

Abstract: Crankcase scavenged internal combustion engine (1) of two-stroke type, intended for a working tool, preferably a chain saw or a trimmer, and provided with a light-weight and compact muffler (2). The engine is arranged with a particularly high crankcase compression created in that at least one filling (3, 4, 5, 6) is placed into the compression area (7) under the engine piston (8) in form of a filled balance (3) and/or a piston filling (4) and/or a piston washer (5) and/or a stationary filling (6), at the same time as the engine is provided with an especially strong throttling created in the engine's exhaust side, i.e. in its exhaust port (9) and/or in a possible exhaust duct (10) and/or in the muffler (2).

Abstract: To provide a 2-stroke cycle internal combustion engine for a vehicle in which less blowoff of a gas mixture occurs in a combustion chamber, fuel consumption is low and high exhaust gas purifying performance is attained. The cylinder of the internal combustion engine is slightly inclined toward the forward side of the vehicle body from its upright position. The high pressure chamber and the communication passages are arranged forwardly toward the vehicle body from the cylinder. Openings of the communicating passages toward the combustion chamber are arranged, from the scavenging port, near the combustion chamber. The intake control valve rotated from the crank chamber near the openings of the communicating passages toward the combustion chamber is arranged near the openings of the communicating passages, and the exhaust pipe and the exhaust expansion chamber communicating with the exhaust gas passage of the internal combustion engine are arranged at a rear part of the vehicle body from the cylinder.

Abstract: An exhaust passage for connecting to an exhaust port of a cylinder is provided. The exhaust passage includes a first path extending in a direction generally orthogonal to the central axis of the exhaust port. A second path connects the first path and the exhaust poil and a control valve is provided in the first path. The rotational axis of the exhaust control valve is generally parallel to the direction in which the first path extends. The surface area of an opening connecting the first path and the second path is variable as the exhaust control valve rotates, so as to carry out controlled combustion and exhaust timing. This makes it unnecessary to provide a hollow section for housing an exhaust control valve and bearing at a position close to the exhaust. It is also possible to reduce the size of a cylinder block and to realize smooth flow of exhaust gases by making the inner peripheral surface of the exhaust passage smooth.

Abstract: A two-cycle internal combustion engine implements low-pressure, cylinder wall fuel injection and uses a notched exhaust port or the like to control cylinder pressure rise during exhaust port closure. An electronic control unit controls the operation of fuel injection through the cylinder wall. Fuel injection terminates before the piston closes the exhaust port as the piston travels from bottom dead center to top dead center. The exhaust port notch tempers pressure gradients and pressure fluctuations in the piston cavity that can otherwise occur before the exhaust port closes and can be detrimental to the control of low-pressure fuel injectors. The exhaust port notch allows better fuel injection control, especially at idle or low speeds, without requiring the port positions and configurations to be modified which could compromise engine performance at medium or high speeds.

Abstract: An improvement in a thermally insulating component for an engine part, made by sintering from ceramic materials, comprises, the thermally insulating component having a composition, consisting of a mixture of zirconium oxide in the range of about 5% to about 25% by volume and mullite in the range of about 75% to about 95% by volume. Further, the mixture of zirconium oxide and mullite is obtained by chemically mixing the zirconium oxide and mullite in their molecular states, rather than mechanically mixing them. Another feature of this invention includes, forming said thermally insulating component by slip casting and pressureless sintering the mixture of zirconium oxide and mullite at a temperature no greater than 1700.degree. C. This improvement in a thermally insulating component for an engine part, made from a mullite-zirconia ceramic composite, embodying the present invention, is particularly useful in making flame decks for cylinder heads, and insulating coverings for pistons and exhaust ports.

Abstract: An exhaust control system for a two-cycle, crankcase compression, direct injection engine wherein an exhaust control valve modifies the effective cross-sectional area of the exhaust system in response to engine speed and operator demand to provide optimum charging and scavenging conditions. The exhaust control system is modified in response to other than normal steady state operating conditions such as during starting, warm up, and during rapid changes in engine speed and/or load and/or operator demand so as to improve performance during these conditions.

Abstract: An exhaust timing valve control for an exhaust timing valve of an engine powering a watercraft is disclosed. The engine has an exhaust port leading from a combustion chamber for routing exhaust products therefrom, the exhaust timing valve cooperable with the exhaust port and movable between a first position for delaying the closing of said exhaust port and a second position for advancing the closing of said exhaust port. The watercraft includes a power source which provides power when the engine is started. The exhaust timing valve control includes a mechanism for turning on the control when the engine is started and the power source provides power, and for turning off the control when the engine is stopped.

Abstract: A control arrangement for a planing-type boat having an engine powering a water propulsion device is disclosed. The engine has at least one combustion chamber, an exhaust port leading from the combustion chamber, and an exhaust timing valve cooperable with the exhaust port. The exhaust timing valve is moveable between a first retracted position and a second extended position, where in the second position a flow of exhaust through the exhaust port has a shorter duration than when the valve is in the first position. A drive unit is associated with the exhaust timing valve. The control is arranged to move the exhaust timing valve with the drive unit from the second position towards the first position at a predetermined high engine speed. The control is arranged to prevent the rapid movement of said exhaust timing valve between its first and second positions when the engine speed fluctuates about the predetermined engine speed.

Abstract: An engine control for an engine powering a watercraft is disclosed. The engine has a body defining at least two combustion chambers. An air supply system supplies air to the combustion chambers, the air supply system including a throttle control for controlling the flow rate of air to the engine, the throttle control moveable between an open and a closed position. A fuel supply system supplies fuel to the combustion chambers. At least one ignition element ignites the air and fuel supplied to the combustion chambers. At least one exhaust passage leads from the combustion chamber to a point exterior to the body through which exhaust may pass. Exhaust control means are provided for controlling the timing of the flow of exhaust through the passage.

Abstract: An exhaust timing valve control for an exhaust timing valve of an engine powering a watercraft is disclosed. The engine has an exhaust port leading from a combustion chamber for routing exhaust products therefrom and an exhaust timing valve cooperable with the exhaust port and movable between a first position for delaying the closing of the exhaust port and a second position for advancing the closing of the exhaust port. The engine includes a coil member providing a pulsed output when the engine is running. The exhaust timing valve control controls the position of the exhaust timing valve, the exhaust timing valve control including an engine speed detector which detects the speed of the engine based upon the output of the coil member.

Abstract: To provide a structure for attaching exhaust control valves near exhaust ports in a two-cycle engine, the exhaust control valves variably controlling open areas of the exhaust ports. The cavity for receiving the exhaust control valves is formed near the upper edges of the exhaust ports on the cylinder block. The holder member is interposed between the cylinder block and the exhaust manifold, is attached to the pivot for supporting the exhaust control valves. A flange is provided for connection with the cylinder block. Therefore, the exhaust control valves are disposed near the upper edges of the exhaust ports. It is not necessary to form bearings on the cylinder block using a complicated process. Complicated parts such as bearings are collectively formed on the holder member that is independent and compact and easily machined. The pivot extends across the exhaust passages that are formed downwardly in order to detour around the pivot.

Abstract: A combustion control apparatus for a spark ignition type 2-cycle internal combustion engine includes fresh air mixed with fuel in a combustion chamber which can be self-ignited at an ignition timing preferable for the operation of the internal combustion engine at least in a low load operation region to effect active thermal atmosphere combustion. When it becomes necessary to stop the internal combustion engine quickly, upon starting of the internal combustion engine again, the starting performance is high. A combustion control apparatus for a spark ignition type 2-cycle internal combustion engine includes fresh air mixed with fuel in a combustion chamber which can be self-ignited at least in a low load operation region.

Abstract: An oil supply system for a watercraft is disclosed. The watercraft has a water propulsion device and a hull defining an engine compartment, an internal combustion engine positioned in the engine compartment and having an output shaft arranged to power the water propulsion device. The engine has at least one combustion chamber and an intake and exhaust path including an air intake system through which air is provided to the combustion chamber(s) and an exhaust system for routing products of combustion from the combustion chamber(s) to a discharge, the exhaust system including a water lock between the discharge and the engine. The engine also includes a fuel supply system supplying fuel to the combustion chamber(s) for combustion with the air. The oil supply system is arranged to introduce lubricant to the engine along the intake and exhaust path upstream of the water lock.

Abstract: An exhaust timing control valve control arrangement is disclosed. The exhaust valve is positioned in an exhaust port of an engine and movable between a retracted position in which the exhaust flow timing is advanced, and an extended position into the port in which the exhaust flow timing is retarded. A control is provided for moving the valve in a cleaning operation after the engine is started and running above a predetermined low speed. The cleaning operation may additionally be performed when the engine is shut off.

Abstract: The present invention is referred to an exhausting valve lid for motorcycles comprising a lid body including several orifices for fastening said lid to the motorcycle engine. Said lid includes means for controlling the force to be applied to the exhausting valve regulating means, controlling therefore the time at which the exhausting valve is to be opened. Said means for controlling the force to be applied comprises a hollow housing projected from the outer surface of lid body, said housing receives a cylindrical hollow aluminum bolt engaged to a pressing spring coupled to said exhausting valve regulating means.

Abstract: A cylinder block for an internal combustion engine includes a mounting surface having therein a crankcase cavity and a pair of cylinders respectively extending from the cavity in acute angular relation to each other and each including a cylinder wall. The cylinder walls include outer ends having cylinder head mounting surfaces, mixture transfer ports, mixture supply ports, gas discharge ports and a main exhaust gas discharge passage. A passage communicates between the exhaust gas discharge ports and with the main exhaust gas discharge passage. Mixture supply passages extend between the mounting surface and the cylinder head mounting surfaces and include reed valves. Branch passages communicate between the transfer ports in the cylinder walls and the mixture supply passages at respective locations between the cylinder head mounting surfaces and the reed valves. Auxiliary supply passages extend from the mounting surface and communicate with the mixture supply ports in the cylinder walls.

Abstract: An exhaust port controlling arrangement for an internal combustion engine having both main and auxiliary exhaust ports. A main control valve cooperates with the main exhaust port for varying the timing at which the exhaust port opens in response to engine speed. An on/off auxiliary control valve is positioned in a passage leading from the auxiliary exhaust port for opening and closing the flow through the auxiliary exhaust passage in response to an engine condition. Means retard the opening of the main exhaust port upon opening of the auxiliary exhaust ports to improve the power and torque curves of the engine.

Abstract: An exhaust valve system for internal combustion engine. The engine includes a cylinder having an exhaust port with an axial extent along the axis of the cylinder structure. An exhaust port valve is mounted adjacent to the exhaust port and is adjustable between a full-flow position, in which the exhaust port valve exposes the exhaust port throughout its axial extent, and a restricting position, in which the exhaust port valve restricts the axial extent of the exhaust port. A valve control module is connected to the exhaust port valve and functions to adjust the exhaust port valve between the full-flow and restricting positions in response to the cylinder bore gas pressure. At low speeds and low output conditions, the valve is in its restricting position. As the cylinder develops higher pressures at higher speeds and under higher output conditions, the valve control module moves the valve to its full-flow position.

Abstract: An exhaust controller includes an exhaust control valve. The exhaust controller is capable of adjusting an exhaust timing of a spark ignition type, two stroke internal combustion engine depending upon the rotational speed of the engine. The exhaust control valve has a structure and operation which greatly reduces exhaust leakage past the exhaust control valve. As a result, the scavenging efficiency and the charging efficiency are improved and the compression ratio of the engine is better maintained. In operation, the exhaust control valve maintains a relatively consistent cross-section throughout the exhaust gas flow passage. As a result, exhaust pressure is decreased, resulting in an increase in the output and efficiency of the engine.

Abstract: An exhaust control apparatus for a high level engine output and engine efficiency for obtaining a stable operation from a low speed to a high operating speed in a spark-ignition two-stroke internal combustion engine with an exhaust timing that can be adjusted. A spark-ignition two-stroke internal combustion engine is equipped with an exhaust channel that opens via an exhaust port into the cylinder, and an exhaust control valve that is supported for reciprocation along the cylinder centerline direction along the exhaust port and that allows at least the portion of the exhaust port on the cylinder head side to be blocked. A valve body depression forms a hollow from the cylinder head side to the crank side in the exhaust control valve by a bottom wall, side walls, and a control wall. A housing depression is provided that allows the above-mentioned exhaust control valve to be withdrawn from the abovementioned exhaust channel.

Abstract: A two stroke internal combustion engine having at least one cylinder (1) with exhaust port means (5), the engine further including at least one supplementary passage (9) in addition to the exhaust port means (5) for allowing gas flow from the cylinder (1), and control means (7) for controlling the gas flow through the supplementary passage (9) as a function of predetermined operating conditions of the engine wherein the control means allows at least substantially unimpeded gas flow therethrough during a compression stroke of the engine when the engine is at least at idle, low engine loads and/or engine speeds, and/or during engine start-up and at least substantially prevents gas flow therethrough when the engine is at higher engine loads and/or engine speeds.

Abstract: An exhaust controller for a spark ignition type two stroke internal combustion engine capable of adjusting an exhaust timing by an exhaust control valve, characterized by sufficiently cooling an outer peripheral wall of an exhaust passage. In a spark ignition type two stroke internal combustion engine, a cylinder head side outer peripheral portion of an upstream portion of an exhaust passage smoothly connected to an exhaust port is formed of an exhaust passage forming portion of a lid member closing an exhaust control valve. A crank case side outer peripheral portion of the exhaust passage is formed of a cylinder block. The cylinder head side outer peripheral portion of the exhaust passage is cooled by a cooling water passage near a cylinder head which is formed in the lid member and the crank case side outer peripheral portion of the exhaust passage is directly cooled by a cylinder block cooling water passage near a crank case which is formed in the cylinder block.

Abstract: Expansion chambers for two-cycle engines include a moveable closure piston which selectively increases the flow cross-sectional area geometrically upon increasing back pressure. The improved expansion chamber thus results in better regulation of the back pressure in the two-cycle engine. Several expansion chamber embodiments are disclosed.

Abstract: A two-cycle internal combustion engine for a watercraft that includes a cylinder block having a cylinder bore, a piston reciprocating in the cylinder bore and an exhaust port formed in the cylinder block. An exhaust path extends from the cylinder bore for exhausting combustion products from the cylinder bore. An exhaust control valve cooperates with the exhaust port and is movable between at least a first position for advancing the closing of the exhaust port so as to increase the compression ratio in the engine and a second position for delaying the closing of the exhaust port so as to decrease the compression ratio in the engine. Means for controlling the exhaust control valve between the first and second position are provided and are controlled in response to a watercraft condition.

Abstract: A two-cycle internal combustion engine control method and system wherein economy of fuel consumption and emission control is achieved by skipping fuel injection for a number of cycles dependent upon a decrease in the engine speed and load below a predetermined value. When fuel injection is skipped, the duration of fuel injection is increased. The escape of unburned fuel from the exhaust port is achieved when the fuel injection amount is increased by advancing the timing of the fuel injection and by retarding the opening of the exhaust port.

Abstract: A two-stroke-cycle engine is provided with a main exhaust port and a pair of auxiliary exhaust ports and includes a main exhaust valve unit slidably disposed to the main exhaust port for controlling an upper edge position of the main exhaust port and a pair of right and left auxiliary exhaust valve units disposed rotatably for opening and closing right and left auxiliary exhaust passages formed to right and left sides of a main exhaust passage formed to the engine. An exhaust controller of the engine is characterized in that a driving unit is connected to the main exhaust valve unit and the right and left auxiliary exhaust valve units are coupled with an end of the main exhaust valve unit on the main exhaust port side through a coupling pin so as to be operatively associated with the main exhaust valve unit, the right and left auxiliary exhaust valve units being disposed symmetrically with respect to the main exhaust valve unit.

Abstract: An engine operation control system for an engine having at least one variable volume combustion chamber with an ignition element corresponding thereto and an exhaust port for controlling the flow of exhaust from the chamber is disclosed. Upon detection of an engine overheat condition, the operation control system operates to advance the timing of the firing one or more of the ignition elements and misfiring these elements, whereby engine cooling is achieved without backfire.

Abstract: A method of operating a two-stroke cycle internal combustion engine having at least one exhaust port communicating with each combustion chamber of the engine and an exhaust valve operably associated with at least one said exhaust port to control the timing of the opening and the flow area through said exhaust port between maximum and minimum values, the method comprising advancing the timing of the opening of the exhaust port in response to idle or low load operation to the maximum extent to maximize the flow area through the exhaust port. Other engine management operations disclosed and claimed include: positioning the exhause valve to reduce the flow area to the minimum extent on cessation of operation of the engine, and impacting the exhaust valve against the limits defining the maximum and minimum values of valve movement to promote dislodgement of carbon deposits.

Abstract: A combustion controller for a two-cycle engine which enables to cause self firing always at the optimum timing is provided. The combustion controller comprises an exhaust control valve 15 provided in the vicinity of an exhaust port 7 of the two-cycle engine 1 and capable of fully closing the exhaust port and driving control means 47, 38, 39, 40 and 37 to drive the exhaust control valve 15 according to a control map giving an exhaust opening ratio .theta..sub.e depending at least on the engine speed and the throttle valve opening ratio .theta..sub.th in order to control the pressure in the cylinder during up-stroke of the piston 8.

Abstract: An exhaust port timing control apparatus for a two-cycle engine includes a control valve which is moved upward and downward in the linear direction across an exhaust port by moving the control valve slidably and rotatably around a supporting axis. The control valve is operated by rotating a pivot provided at an end portion of the control valve. Since the control valve moves linearly, the clearance between the control valve and the exhaust port can be kept very small, whereby the leakage of gas out of the cylinder can be minimized and consequently an accurate exhaust port timing control and a stable engine operation are achieved.

Abstract: An exhaust arrangement for an internal combustion engine wherein the timing of the cylinder events is such that the exhaust port of one cylinder opens before the exhaust port of another cylinder closes so as to improve scavenging and performance. In preferred embodiments, the engine is of a 2-cycle type and the exhaust port of the one cylinder also opens before the scavenge port of the other cylinder closes. The principle is also depicted in conjunction with a four cylinder engine.

Abstract: Several embodiments of two-cycle internal combustion engines having exhaust control valves that include butterfly-type valves for minimizing the likelihood of sticking and reducing the area where deposits could form that would interfere with the valve operation. The butterfly-type valves are journaled in a separate valve housing that is mounted in a transversely extending bore that extends through the cylinder block of the engine for facilitating servicing.

Abstract: An exhaust control valve arrangement for a two cycle internal combustion engine for altering the compression ratio to provide optimum running under all conditions. An arrangement is provided or cleaning the exhaust control valve and its surrounding cooperating surfaces of the engine upon shutting off of the engine to preclude the formations of deposits that can cause sticking of the valve element. The valve element is rotated through a number of cycles after the engine is stopped through a wider range than during its normal valving operation for removing deposits. The number of cycles is chosen in response to an engine condition such as length of time of running or amount of lubricant supplied to the engine. Various valve arrangements are disclosed that improve the cleaning operation and permit cleaning even while the engine is running.

Abstract: A deceleration control apparatus is provided which can control a two-cycle engine of the spark ignition type for a vehicle, in which fresh air in a combustion chamber can be self-ignited at an ignition timing preferable for operation of the engine at least upon low load operation, so that, when engine sudden deceleration requirements are satisfied, the combustion condition is automatically changed over from an activated heat atmosphere combustion condition to an ordinary combustion condition to allow sudden deceleration of the engine.

Abstract: An exhaust control drive arrangement for an internal combustion engine for varying the exhaust port timing and effective compression ratio. The exhaust control valve is driven by a servomechanism mounted directly on the cylinder block at one end of the engine and adjacent the flywheel so as to provide a compact assembly.

Abstract: A two stroke engine (10) has an exhaust port (16) extending from a side wall of a cylinder (12). A plate valve (26) is movable to an extended position where is the plate valve blocks the upper edge (54) of the exhaust port 16 to effectively retard the opening of the exhaust valve and retractable to a second position which provides the entire axial extent of the exhaust port (16) to be openable with respect to the cylinder. The position of the plate valve (26) is controlled by a diaphragm bladder (46) which is responsive to pressure in the intake system (19) that is in communication with the bladder (46) via an inlet passage (48).

Abstract: A two-cycle crankcase compression diesel engine having a scavenge control system for controlling the amount of scavenging flow and an exhaust control system for controlling the effective compression ratio and the effective flow area of the exhaust system. These controls are operated during normal engine running conditions at most speed ranges from a three dimensional map. However, special control routines and valve operating arrangements are provided for pre-starting, starting, idle, engine braking or deceleration and rapid acceleration so as to improve the running under these transient or non-normal conditions.

Abstract: A two-cycle engine of the spark ignition type is provided wherein a mixture in a combustion chamber can be compressed and self-ignited at least in a low load operation region to effect an activated heat atmosphere combustion. In a transition operation region between the activated heat atmosphere combustion region and an ordinary spark ignition combustion operation region, the mixture can be ignited by a spark ignition at a timing earlier than the spark ignition timing in the ordinary spark ignition combustion operation region to stabilize the combustion condition and eliminate abnormal combustion noise and the harmful effects of heat. A throttle valve opening of a throttle valve manually operated is detected by a throttle valve opening sensor formed from a potentiometer or the like while an engine speed is detected by an engine speed sensor, and they are inputted to a CPU. The CPU operates in accordance with a control graph of FIG.

Abstract: An exhaust control system for a two-cycle engine for controlling the effective compression ratio. The exhaust control valve is operated by a servo mechanism to maintain the appropriate compression ratio in response to engine running conditions. To facilitate servicing, the exhaust control valve is rotatably journalled within the engine cylinder block in a removable sleeve. In addition, a manual operator is provided for manually rotating the exhaust control valve for cleaning operation and to reduce sticking if corrosion occurs.

Abstract: A method and apparatus of a two-stroke combustion engine is provided. The invention relates to utilizing the compression of the flue gases that remain in the cylinder, and the intake of a combustible air-fuel mixture in a limited zone of the combustion chamber, where the mixing of the air-fuel mixture and the flue gas is minimized. The combustible air-fuel mixture is ignited into the limited zone of the combustion chamber.

Abstract: A power device for driving an auxiliary equipment for an internal combustion engine capable of driving both a fuel injection unit and a valve without specifically providing a adjusting valve when the engine includes no battery acting as a power supply. A generator driven by the internal combustion engine is provided therein with a generating coil for driving the auxiliary equipment which is common to both a pump motor and an actuator. A driving power feed circuit is arranged for feeding driving power to the pump motor and actuator from the generating coil for driving the auxiliary equipment which acts as a power supply. The driving power feed circuit includes a pump driving switch for switching a driving current of the pump motor, an actuator driving switch for switching a driving current of the actuator, and a switch control unit for turning on the pump driving switch and actuator driving switch at duty ratios different from each other, respectively.

Abstract: An exhaust control valve arrangement for a two cycle internal combustion engine for altering the compression ratio to provide optimum running under all conditions. An arrangement is provided for cleaning the exhaust control valve and its surrounding cooperating surfaces of the engine upon shutting off of the engine to preclude the formations of deposits that can cause sticking of the valve element. The valve element is rotated through a number of cycles after the engine is stopped through a wider range than during its normal valving operation for removing deposits. The number of cycles is chosen in response to an engine condition such as length of time of running or amount of lubricant supplied to the engine. Various valve arrangements are disclosed that improve the cleaning operation and permit cleaning even while the engine is running.

Abstract: An exhaust port is formed in the wall of a cylinder of a 2-cycle engine. At least one of the portions of the cylinder wall which define two vertically opposing edges of the exhaust port is projected at the circumferentially mid portion towards the opposing edge so as to provide a piston guide surface which conforms with the inner peripheral surface of the cylinder and which extends in such a manner as to reduce the axial height of the exhaust port. The piston guide surface serves to suppress vibration and noise caused when an upwardly moving piston falls into the exhaust port.

Abstract: A two stroke cycle engine cylinder block (9) has exhaust ports (14) controlled by power valves which rotate on an axis extending longitudinally of the block (9). Along this axis the block (9) has a plurality of aligned recesses in which are located bearing members (24) for the power valves. Bores (25) in each bearing member (24) are axially aligned and the bearing members (24) immobilely retained in the aligned recesses by assembly of the exhaust manifold (16). Spigots on the power valves are received in the bores (25) and coupled together so that the power valves rotate in unison.

Abstract: An exhaust control device for a two-cycle engine which does not impart a change of a shape of an exhaust passage. An exhaust control device is provided in an exhaust port opening to an inner peripheral surface of a cylinder hole of a two-cycle engine wherein a cylinder wall portion adjacent to the exhaust port is formed with a rotational face obtained by rotating an arc having substantially the same curvature as the inner peripheral surface of the cylinder hole about a rotational axis C.sub.1 extending at a right angle to an axis C of the cylinder hole in the outside of the cylinder hole and a recess defined by both ends at a right angle to the rotational axis C.sub.1 and in communication with the exhaust port.

Abstract: A fuel injection and control system for a V-type, two cycle, crankcase compression, internal combustion engine. The fuel injection system includes fuel injectors positioned in the valley of the engine and which are supplied with fuel under pressure from a fuel tank through a line in which a fuel filter and fuel pump are positioned. The fuel pump and fuel filter are disposed at one end of the engine and the amount of pressure supplied to the fuel injectors is controlled by a pressure regulator that regulates pressure by bypassing excess fuel back to the fuel filter upstream of the filter element. A throttle control and throttle position sensor are disposed at the opposite end of the engine and exhaust control valves are provided outside of the valley of the "V" of the engine.

Abstract: A two cycle interal combustion engine constituting of upper exhaust ports and a lower exhaust port provided on the upper and the lower of the level of the upper edge of scavenging ports, respectively, and having only the upper exhaust ports connected to a cleaning device. As a result of that, exhaust gas containing large amounts of hazardous components is mainly discharged from the upper exhaust ports and, because the exhaust gas can be cleaned concentratively, the decontamination efficiency of exhaust gas is good.

Abstract: A two-stroke engine comprising two exhaust valves and two intake valves. These exhaust valves and these intake valves are arranged on the peripheral portion of the inner wall of the cylinder head, and one additional exhaust valve is arranged on the central portion of the inner wall of the cylinder head. The valve openings of the two intake valves, which are located on the exhaust valves side, are masked by the masking walls.

Abstract: An exhaust timing controller for a two-stroke cycle engine includes an exhaust timing control valve for changing a height of an open edge portion on a top dead center side of an exhaust port opening to an inside wall surface of a cylinder bore in the engine. The exhaust timing control valve moves axially of the cylinder bore by power from an actuator and the exhaust timing is accelerated in response to rotational frequency rises in the engine. The power of the actuator is transformed into an elevating stroke of the exhaust timing control valve by the eccentric motion of an eccentric cam. A slider mechanism for transferring an eccentric motion of the eccentric cam to the exhaust timing control valve is provided between the eccentric cam and the exhaust timing valve. A straightening member extends smoothly from a portion of the exhaust timing control valve, which retracts into the exhaust port, on the downstream side of the exhaust port.