Showing posts with label Pulse Air Valve. Show all posts
Showing posts with label Pulse Air Valve. Show all posts

Friday, 27 April 2012

Royal Enfield Pulse Air Valve


When an engine exhaust valve is open, the pressure in the exhaust manifold is higher than atmospheric pressure. The exhaust manifold is configured in such a way that positive and negative pulses are produced during the operation of the cycle by designing it as adiffuser.

The main function of Pulse Air Valve to burn the excess pollutants out of the exhaust.
The Pulse Air Valve make air sucked into the exhaust port to encourage heat into the exhaust flame and burn of exess carbons.

The Pulse Air Valve  has three openings one is connected to the manifold vacuum, another is connected to the exhaust pipe and the third is open to the atmosphere. When a negative pulse is induced in the exhaust, air from the atmosphere enters the exhaust manifold through a one-way reed valve and serves to oxidize the carbon monoxide and hydrocarbons in the exhaust.

This system consists of a spring-loaded diaphragm, and a shaft which is attached to the bottom. A manifold vacuum is applied over the diaphragm where the shaft end is towards the opening of the atmosphere.
During deceleration, the engine vacuum rises and acts against the spring to push the shaft downwards, thereby blocking the opening through which atmospheric air is passed to the exhaust.

The Royal Enfield Bullet, from year 2006-current, uses an Air Suction Valve to reduce emissions in its exhaust gases. Royal Enfield Motors calls their Air Suction Valve the PAV, or Pulsed Air Valve. Its function is the same, using a vacuum at the intake to trigger a valve that pulses atmospheric air into the exhaust. The original "iron barrel" style engine did this with a hose from the PAV going to the exhaust pipe, the newer (2003–2009) AVL aluminum engine pulses the gas directly into the exhaust port on the head of the engine itself.



Thursday, 26 April 2012

Back Pressure in Royal Enfield


“Back pressure is the pressure drop in the flow of gases from engine to exhaust. The less power engine has to spend making pressure to push the gases from exhaust output, the more power it can send to the wheels”.


The term back pressure is misleading as the pressure remains and causes flow in the same direction, but the flow is reduced due to resistance. For example, an automotive exhaust muffler with a particularly high number of twists, bends, turns and right angles could be described as having particularly high back pressure.


The exhaust having maximum bends will have the higher back pressure resulting in negative effect on engine efficiency resulting in a decrease of power output that must be compensated by increasing fuel consumption. Less back pressure makes engine able to transfer maximum power to wheels and keeps it less heated up.


The motorcycle's exhaust pipe is connected to the cylinders in the engine. When the engine is operating, it circulates gas throughout the system. The gas expands as it circulates through the engine, then finds its way into the cylinders. Some of the gas is not expelled out of the exhaust pipe, and it then creates exhaust back pressure. All of the gas pressure should leave out of the cylinders and into the exhaust pipe at a constant rate. If the rate is thrown off balance, then you have the result of exhaust back pressure in your motorcycle. Many believe that there is no effect on your engine when motorcycle exhaust back pressure is formed. Either way, it is not normal for exhaust back pressure to occur.


Back pressure caused by the exhaust system of an automotive four-stroke engine has a negative effect on engine efficiency resulting in a decrease of power output that must be compensated by increasing fuel consumption.  



Free Flow silencers has less back pressure than that of stock silencers that is why we bulleteers prefer louder sound but the fact behind it that a free flow silencer helps in less heating up of engine and louder sound as we alwayz want.



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Monday, 2 January 2012

ROYAL ENFIELD BULLET ELECTRA TWINSPARK 350cc - REVIEW / ROAD TEST / DESIGN / SPECIFICATIONS / PRICE








Thump lovers rejoice, Chennai based Royal Enfield has launched an all new Electra with Twin Spark Unit Construction Engine (UCE). The engine has been borrowed from its sibling Thunderbird Twinspark. With a slew of launches in the past few months along with announcements of expansion plans, Royal Enfield has cleared the air that they want to take it headon.

Similar to Thunderbird, Electra with two spark plugs produces 19.8 horses and a mammoth torque of 28Nm. Clearly, these are good signs that traditional bike makers like Royal Enfield are also concentrating on revolutionizing their bikes with better and latest technology.

Engine, Transmission & Performance

The new Royal Enfield Electra Twinspark is powered with a 346cc engine that generates a maximum power of 19.8 bhp at 5250 rpm and a torque of 28 Nm at 4000 rpm. The Electra Twinspark uses a BS29 / UCAL carburetor. The motorcycle company claims that the Electra Twinspark is capable of hitting a top speed of 120 kmph. Now engine is made from aluminum alloy, and weight of the motorcycle is only 180kg. Unfortunately, exhaust sound is not so powerful as its predecessor – the standard Bullet thanks to new glass wool filled silencer by royal enfield, which not only reduces noises and heat transmission, but also complies with Euro 3 reduced emission norms. But hey if you badly need more thump, you can always choose several after market options for exhaust system. Compression ratio on the Bullet Electra Twinspark is 8.5:1

The UCE facilitates smoother operation, power delivery and cleaner emissions too according to the company. The bike has gas-filled shock absorbers that enable smooth riding over potholes and speed breakers. The bike can touch a top-speed of 120kmph and will give you a mileage of around 30-40 kmpl. But the mileage might vary depending on the condition of the bike and how you actually ride it. Well, RE bikers are very well aware of the fact that the Bullets aren’t for mileage.

Coming to transmission part, the bike comes laoded with a Constant Mesh 5-speed. Upshifting/downshifting feels nice and smooth, and the power range  spreads out very evenly. With much shorter gear ratio it feels a bit like a Japanese sports bike. Here comes the problem- Locating neutral is still a problem with this bike but according to a royal enfield mechanic there is nothing to worry and the problem will vanish automatically once the bike completes 1500-2000 kms on odo.

Available color options -
 
There are two variants of the new Royal Enfield Electra Twinspark- the kick-start model (Electra Twinspark KS) and the auto or the electric-start (Electra Twinspark ES) version. And, the bike will be available in vibrant colors of Black, silver and red.
  
Mileage / Fuel economy -

As far as fuel efficiency is concerned, the new electra with uce engine scores over old electra with cast iron engine. Royal Enfield Bullet bullet electra twinspark 350cc is supposed to give 40-45 kmpl of fuel economy. though official figures is somewhere around 51 kmpl (ARAI) but we got around 38 kmpl in city conditions and whopping 43 on our highway ride !! 


Pricing -

There are two different Electra TwinSpark models available – kickstart (KS) and electric start (ES). The bikes are available in three colors- red, silver and black.  The Bike offered by Royal Enfield was a gorgeous Black with Chrome tints  as you see. Ex-showroom prices of Delhi are Rs. 1,10,500. (Price vary in different cities)

Brakes & Suspension -

now you don't have to anticipate your braking since the all new electra comes with hydraulic 280mm front disc set-up which are way better than the old drum brake. The Front suspension is hydraulically damped telescopic forks, stroke = 130mm. The rear suspension is swing arm with adjustable gas shock absorbers, stroke = 80mm. Suspension is good and provides comfortable ride until you need to ride on the rough terrain, then it becomes a little rough. But on the usual roads there are no problems with it though. Overall braking power on Electra TwinSpark is more than sufficient, and suspension is reliable and mild.

Dimensions -

The overall length, height and width of Royal Enfield Bullet electra are 2140, 1120 and 810mm respectively. The wheelbase(1370mm), saddle height (800mm) and ground clearance (140mm) are same in both the machines. The curb weight of electra twinspark is 180 kg for kick start version and it is 183 kg for electric start.

Features and Benefits:

•Aluminum alloy Lean-Burn engine
•Five-speed transmission with modified gearing
•Higher speeds, better handling
•Gas-filled shocks
•Capacity for higher speeds, better handling
•Environmentally friendly with lower emissions and increased fuel economy

Summing it up:

No other bike can have as huge or lasting an impact on your life as the Bullet. The Bullet can transform your outlook towards life, no less! One stands taller, shoulders feel broader, chest swells up and arms feel infinitely stronger. You feel invincible, like nothing or no one can lay a finger on you. (This invariably causes most problems but while the feeling lasts, it's great). While riding her, your hectic cutthroat schedule somehow seems to lighten up. As you use her, you develop a telepathic bond with the bike, she becomes a part of your system like no other bike can ever hope to. The riding pleasure that the Bullet offers is unmatched bar none. Sure when you get to a stretch of bad tarmac, your backbones are in for a little rearrangement but out on the open road, a couple of 100km from your destination, the throb of the 350cc lump between your legs, the fantastic exhaust note making merry music at a steady 90kmph... that's what touring is all about. That's what the Bullet is all about.



TECHNICAL SPECIFICATIONS:



EngineSingle Cylinder, 4 Stroke, OHV, SI engine, air cooled, Twinspark
Displacement346 cc
Bore x Stroke70mm x 90mm
Maximum Power19.8 bhp @ 5250 rpm
Maximum Torque28 nm @ 4000 rpm
TransmissionConstant Mesh 5 speed
IgnitionDigital TCI
CarburetorBS29 / UCAL
Dimensions
Ground Clearance140 mm
Width810 mm
Wheel Base1370 mm
Length2140 mm
Height1120 mm
Seat Height/ Saddle Height800 mm
Tyres
Front3.25 x 19"
Rear3.25 x 19"
Electricals
Electrical System12v - DC for ES / 12v - AC/DC for KS
Head lamp12v, 35/35w
Battery12v - 14AH MF for ES, 12v - 5AH for KS
Tail Lamp12v, 5w
Brakes
FrontHydraulic 280mm Disc
RearFoot operated 153 mm single lead internal expanding
Maximum Speed
Speed120 kmph
Suspension
FrontTelescopic, hydraulic damping, stroke 130 mm
RearSwing arm with gas shock absorbers, Stroke 80 mm
Vehicle
Fuel Tank Capacity13.5 ltr (min)
Compression Ratio8.5 : 1
Engine Oil Grade / Qty15w, 50 API, SL Grade jaso ma
Weight(Kerb)KS: 180 kg, ES: 183 kg


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