Honda EXP-2 ~ Motorcycle News — Motorcycle Reviews — Motorcycle Videos…

12 Апр 2015 | Author: | Комментарии к записи Honda EXP-2 ~ Motorcycle News — Motorcycle Reviews — Motorcycle Videos… отключены

Honda EXP-2

Get ready for a comeback of two-strokes in the near with engines that can with four-strokes head-to-head in cleanliness, fuel economy, and all the while retaining power, and weight advantages over Off-road and motorcross riders long enjoyed the benefits of which have evolved highly reliable motors. For you street riders out there, have been a thing of the banned in the U.S. for their emissions since 1985 and over).

Just when fans had given up and bought clapped-out two-… street Honda is now poised to bring back.

Big Red has designed and built a two-… prototype that has comparable to a four-…. Named the this bike has demonstrated the of a rebirth of the two-… engine as an friendly machine. Two-strokes several advantages over four-… counterparts: For a given displacement, a two-… is lighter, produces more power, and has moving parts.

This it less expensive to manufacture especially since the motors can be to smaller, lighter chassis more reliable, and easier to than a four-…. Two-strokes their disadvantages as well they produce more carbon monoxide and hydrocarbon than four-strokes, putting outside the realm of on-road laws in America, and outside requirements of other countries.

In developing countries with restrictive or non-existent emissions two-strokes are the motor of choice for the of motorcycles. In fact, they are so used that Honda two- and four-… engines are in equal quantities worldwide. The for current two-strokes are vast, but a of environmentally friendly emission puts current two-… in jeopardy.

The curved yellow valve on a pivot to open and close the port; it is shown in the closed

Two-strokes have their as well — they more harmful carbon and hydrocarbon emissions than putting them outside the of on-road emissions laws in

The causes of high emissions of engines are relatively simple, and are to the basic way a two-… operates. are two main factors which poor emissions: Incomplete of fuel at low engine RPM, and of unburnt fuel out with the at high engine RPM, both problems compounded by the that oil is injected into the to lubricate the crankshaft, and is then off in combustion.

The EXP-2 was designed to the first of these problems occurs because, during the cycle, fuel enters the through the intake port in the of the cylinder, and pushes spent out of the exhaust port in the opposite wall at the same time. In this, the fuel and exhaust mix causing some exhaust to in the cylinder with the incoming

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the spark plug fires and the fuel mixture, some of the is isolated from the resulting by the exhaust still in the cylinder, and not burn. What Honda has is to develop a way to ignite all the fuel in the by using the properties of auto-ignition, and has this process Activated Combustion. This title is from the way fuel actually

When the fuel is brought to the pressure and temperature, the molecules down into what are as active radical molecules. are highly unstable chemical which are an intermediate step in the combustion reaction.

When hot gas remains in the cylinder, it contains a percentage of active radical when these are combined the incoming fuel charge, the mixture begins to auto-ignite at temperature that a pure mixture. What we currently with auto-ignition is engine a phenomenon that occurs the fuel ignites before the plug fires, while the is still on the up-….

Cut-away of the exhaust valve

There are two factors which cause emissions: Incomplete combustion of at low engine RPM, and expulsion of fuel out with the exhaust at engine RPM

Cut-away diagram of EP2

In the EXP-2, Honda has developed an port valve which and lowers the top of the exhaust port, decreasing and increasing the fuel pressure in the cylinder as needed. valve is similar in shape to a valve, but larger, and is shown in in these two cut-away diagrams.

By setting the valve position on engine RPM and throttle position, the required for auto-ignition can be achieved at the right timing, causing all of the in the cylinder to burn completely. process has the added benefit of low RPM power and throttle response, a problem area with The steps of this process can be in the three part diagram Honda EXP-2 combustion

1. Fresh fuel (white) the combustion chamber, pushing the (grey) out the open exhaust on the opposite side of the cylinder.

2. The fuel mixes with the and some pockets of fuel are within the exhaust. The exhaust closes and the compression of the mixture is as the piston travels upward.

3. The mixture is compressed and auto-ignites as the reaches the top of its …. This all of the fuel, and reduces the emission of hydrocarbons into the environment.

By misfiring, the motor actually much more of the fuel it consumes.

At small throttle a conventional two-… will a repeating pattern of misfiring, allows a large amount of gas and oil to be expelled directly into the At these low engine speeds, the of fuel entering the combustion is small compared to the amount of remaining, which creates a that is not ignited by the spark, and is directly into the exhaust

Each time this occurs, the amount of fuel in the cylinder increases, until it is enough to be ignited by the spark. it is ignited, the cylinder is again with exhaust and the cycle itself.

By measuring cylinder over time, this can be seen as a pattern of regular increases in pressure. The increases in mark the points where the burns; between these peaks is the area where all of the and oil are going out the pipe without which is a major source of and exhaust system contamination.

As can be from the graph below, cycle occurs at low and medium during conventional two-…

Plot of cylinder pressure vs. for conventional two-… at light and reduced loads. The vertical are firing cycles, and the area peaks are misfires.

By igniting the mixture without the use of a spark, the is able to burn all of the fuel and oil in the in every cycle, eliminating the cycle described above. By misfiring, the motor actually much more of the fuel it consumes; this reduces the of unburned fuel and oil released the atmosphere, which greatly hydrocarbon emissions. The graph of pressure below illustrates the constant pressure, which that the fuel is burning on cycle.

Plot of cylinder pressure vs. for EXP-2 two-… at light The smoothness of the graph indicates regular combustion with no

Honda’s riding team of Miller, Paul Ostbo and Bringle finished 7th overall and in class in the Baja 1000.

As a for this technology, Honda a 400cc single-cylinder bike for and desert endurance racing. The single design was chosen it has a large combustion chamber and a piston speed, making for burn characteristics; if the EXP-2 works for this configuration, it work for smaller piston Fuel injection was also for ease of setup and fuel although the system was designed to with carbureted systems as

The race results were good even though the was not designed to win races, but to test new

What all this boils to is that the EXP-2 has about the real-world performance as the 780, but substantially better fuel and lower emissions.

When the settled, the EXP-2 had earned 5th and 1st in both the under 500cc and classes at the Granda-Dakar rally; 1st in the class and 8th overall in the Nevada last year, and 7th overall at the Baja 1000.

Compared to Honda’s current four-… twin rally bike, the EXP-2 has very si

out a riding impression by our tech

milar performance with advantages. While the single EXP-2 produces 54hp to the big 71, they both make 58 of torque, but the EXP-2 is 118 pounds giving it a slightly better ratio. What all this down to is that the EXP-2 has the same real-world performance as the but with substantially better economy and lower emissions.

By the mileage of the bike, it can be raced less fuel, which handling and decreases rider The problem of unburnt fuel with the exhaust has yet to be solved, but for all you …-hards out there: stay this is the start of something we all been waiting for.

Honda EXP-2


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