Login
Password

Forgot your password?

Pressure Ratio Simplified

By Edited Aug 2, 2016 0 0

If you're driving a Harley-Davidson bike you must understand it's motorized with a twin cylinder, reciprocating piston, internal fusion motor. Reciprocating pistons usually means the pistons go top to bottom, or backwards and forwards, or from side to side based upon motor unit settings.

Many factors find the functionality of the bike's motor however, one of the most basic certainly is the compression ratio of the piston,head/cylinder installation. The larger the compression rate is, the more punch or power for each cylinder, up to a point.

An alternating piston of the bike's motor generates hp by combusting an air-gasoline mix to drive the piston inside the cylinder. This linear drive is known as the power stroke. The straight-line movement of the connecting rod-piston fitting is moved to the flywheel, which in turn transforms the linear mechanism to circular motion. This circular motion is then sent to the transmission, and on to the rear end wheel, producing forward motion. Sounds easy, but actually may seem far more complicated.

The pistons in a H-D V-twin are designed to deliver a certain compression ratio in a given application for best operating efficiency. Past experiences and customs have trained Harley-Davidson designers the very best compression rates for bikes driven on the highway.

To streamline things let's work with a single cylinder motor as an example. A regular 4-cycle single cylinder motor (1 / 2 a twin cylinder motor) works in a number of distinctive phases or cycles. That is why it is called a 4-stroke motor (or engine). Through the intake stroke (1), air/fuel
is sucked in by vacuum pressure through the exposed intake valve while the piston moves down. As the piston starts back up (2) the intake valve closes and then the gasoline and air mix is compacted. As the piston reaches the top of the cycle the air/fuel mixture is fired by the spark plug then the piston is forced straight down violently via the expanding air/fuel mix (3), creating the before mentioned straight line motion that is transformed through the flywheel into circular energy. As the piston returns up (4), it drives the burnt mixture released (exhaust gases). which is called the exhaust cycle.

lf the compression ratio is minimal, the bike's motor makes minimal power. lf the compression rate is comparatively higher the motor can generate a great deal more power for each cubic inch of displacement than an equal motor with a reduced compression setting rate. Many things affect the ability to be able to handle a motor with higher compression, not to mention the option of high-octane gas. With out a supply of high-octane fuel, a high compression motor could be afflicted by pre ignition (pinging), due to the gas air mixture shooting prematurely. Pre ignition can be hugely destructive for a motor.

Compression rate is defined plainly as the volume above the piston at bottom-dead-center (BDC), separated by the volume on top of the piston at top-dead-center (TDC). The greater pressurised the gas and air blend is when burned the bigger the force. An increased hit means much more power, together with extra stress on all the physical elements included. High compression motors must the usage of high-octane fuel to avoid pre-ignition and/or detonation, which can bring on expensive damage to pistons, valves, and piston rings or perhaps a lot worse, not winning the race.

For everyday street riding many qualified technicians recommend a compression ratio around 8.5:1 and 9.5:1. Any higher and a higher octane fuel need is necessary. With compression rates under 7:1 a bike's motor simply cannot work effectively. Hopefully at this point you realize what compression ratio means. But, this is just static compression ratio. Cam lift and valve overlap as well as other components assess the real or functional compression rate. In addition, keep in mind that higher compression ratios while boosting power can also increase wear and tear on the bike's motor. High compression motors usually are not good commuter bikes, as lower compression motors are not excellent racing bikes.

This season, bike runs are set to kick off from all over the country. Multitudes of motorcyclist will undoubtedly be gathering for one week of festivity all sharing their love for bikes. You will hear a number of tales and building tips to talk about with different buddies as you ride the time in the bike run. Make sure to drive safe and put on the required safety equipment like carbon fiber helmets. Have fun and have a wonderful ride.

Advertisement

Comments

Add a new comment - No HTML
You must be logged in and verified to post a comment. Please log in or sign up to comment.

Explore InfoBarrel

Auto Business & Money Entertainment Environment Health History Home & Garden InfoBarrel University Lifestyle Sports Technology Travel & Places
© Copyright 2008 - 2016 by Hinzie Media Inc. Terms of Service Privacy Policy XML Sitemap

Follow IB Auto