Two-… power valve system — Wikipedia, the free encyclopedia

28 Апр 2015 | Author: | Комментарии к записи Two-… power valve system — Wikipedia, the free encyclopedia отключены
Suzuki Power Free E1

Two-… power valve

The two-… power valve is an improvement to a conventional two-… that gives a high output over a wider RPM


Operation of a two-… [ edit ]

A … is the action of a travelling the full length of its In a two-… engine, one of the two strokes the intake … and the compression while the other … the combustion … and the exhaust .

As the piston travels upward in the it creates low pressure area in the ; this draws fresh air and fuel from the carburetor a hole in the cylinder wall or into the crankcase. As the piston travelling upward, transfer and the exhaust ports are closed thus trapping the combustible in the combustion chamber. As the piston the top of the cylinder, the mixture in the cylinder is to the point of ignition .

The second begins once ignition has place. The power … after the air-fuel mixture is The burnt fuel creates in the cylinder above the piston and it downward. As the piston passes the of the downstroke, the exhaust port to the of the cylinder is uncovered and initiates the of burned fuel out into the chamber or muffler through the .

The piston then moves the air-fuel mixture remains the previous intake-compression …. after the exhaust port is by the downward travel of the piston, the ports begin to be uncovered. The ports act as a passage through the air-fuel mixture moves the crankcase into the cylinder the piston.

Once the piston the bottom of the …, the second is completed and the process is repeated.

design improvements [ edit ]

The moving parts inside two-… engines are the crankshaft, the rod, and the piston. It is the same in design, however, that a two-… engine to be less and produce high specific of undesirable exhaust gas emissions. At the of the power …, the transfer which deliver fresh are open at the same time as the port.

This can allow a significant of fresh fuel to run straight the engine without ever available for power production. designed exhaust systems minimize the amount of raw fuel in the exhaust process, but a two-… will always waste fuel (modern direct engines being an exception to

Many producers of two-… bikes fit them with the valve systems. These act to vary the height (and of the exhaust port thereby power delivery over a rev range. Exhaust ports fixed dimensions only usable power in a narrow rev which also affects consumption and emissions.

In a race this is not a problem as the engine be operating at high RPM almost all the However, in a road/commuter bike, the power range is a problem. To more low RPM power, as well as the engine to produce a lot of high RPM a power valve system is

All power valve systems the duration of the exhaust port time, which gives the usable low end power combined excellent top end power. Manufacturers also included sub exhaust that extend the ‘tuned of the expansion chamber.

Power valve actuation can be by (RPM dependent) or electric motor) means increasingly electronic control. Electronic offers a greater degree of as well as being able to the opening of the valve and be tuned to

Suzuki AETC and Super [ edit ]

AETC and Super Suzuki engines, Automatic Timing Control: The two-blade was fitted to the VJ21 RGV250, and the version, to the VJ22 RGV250 and RG150 .

With the AETC the power-valve systems are normally closed at low RPM; when it enables the engine to make power. Up to a certain point, power drops off as the engine is to expel enough gases out of the When the power-valve is opened, it more gases to flow out of the port. This system is by a small box above the exhaust the power-valves are situated in this

Depending on the valve, they may be of two (older version) or three version) separate blades.

YPVS-Yamaha Power Valve [ edit ]

YPVS Yamaha Yamaha Power Valve Yamaha engineers realized by altering the height of the exhaust they could effectively the engine power delivery having optimal power and across the entire rev range, so it was the YPVS was born. The valve is of a design running across the top of the port, it is turned by a servo controlled from a control box information from the CDI (and locations).

The valve is a slightly shape. This changes the and size of the exhaust port at engine speeds, maximizing the power at all rev ranges. opening up at 3k rpm for low end power, gradually in between fully opening at 6k rpm for maximum on most 125cc.

It was fitted to all of the models of the RZ/RD two-… bikes (125, 250 350 and 500 cc), the TZR was also added to the DT(125lc range after 1984 was locked closed to comply UK learner regulations until in 1988-04 which had a fully YPVS valve) the dt125r has a design of engine,although not much in speed, just more than its predecessor. The YZ series of bikes has a mechanical power which is activated at RPM speed.

The YPVS is only found on the bikes not air cooled versions. have also used a version in some of their models such as the TZR250R SPR

Yamaha was actually the first to produce consistent results their YPVS in their bikes. The 1977 OW35K was the race bike to incorporate the valve system and it won the Finnish GP in The Kadenacy effect was harnessed and to a point that gave great advantage over all the manufacturers throughout the late and into the mid ’80s.

The first bikes with YPVS the RZ/RD350 YPVS (LC2-onwards), and GP Replica in 1983-84.

Honda [ edit ]

ATAC System: The Automatic Torque Amplification system works by effectively or decreasing the volume of the exhaust with a small butterfly located just before the connection. At low RPM a centrifugal crankshaft gear opens the valve a small chamber and increases the of the exhaust by allowing the exhaust to flow through the chamber. At RPM the ATAC valve is closed and the simply exits into the chamber.

A larger expansion chamber for more power at lower because of the extra time for the impulse to bounce back for the effect. It was used on their CR GP bikes and MTX, MVX, NS and NSR bikes.

Honda Power valve [ edit ]

HPP valve. A governor opens and closes a exhaust valve (using 50 parts)

Suzuki Power Free E1

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