It has been suggested that this article or section be merged with rev limiter. (Discuss) Proposed since October 2009.
This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (September 2008)
This article discusses the term "redline" as it applies to internal combustion engine technology. For other uses of the term, see Redline (disambiguation).
Tachometer showing red lines above 14,000 rpm.

Redline refers to the maximum engine speed at which an internal combustion engine or traction motor and its components are designed to operate without causing damage to the components themselves or other parts of the engine.[1] The redline of an engine depends on various factors such as stroke, mass of the components, displacement, composition of components, and balance of components.

Contents

Variation of redline [link]

Engines with short strokes can handle higher rpm because there is less force in reciprocating motion. Lighter components can increase the redline as well, since they have less inertia and decrease forces present in the engine.

Redlines vary anywhere from a few hundred revolutions per minute (rpm) (in very large engines such as those in trains and generators) to more than ten thousand rpm (in smaller, usually high-performance engines such as motorcycles and sports cars with pistonless rotary engines). Diesel engines normally have lower redlines than comparatively-sized gasoline engines, largely because of fuel-atomization limitations. Gasoline automobile engines typically will have a redline at around 5500 to 7000 rpm. The Ariel Atom 500 has the highest redline of a piston-engine road car rated at 10,600. The Renesis in the current Mazda RX-8 has the highest redline of a production rotary-engine road car rated at 9400 rpm.

In contrast, some older OHV engines had redlines as low as 4800 rpm, mostly due to the engines being designed and built for low-end power and economy during the late 1960s all the way to the early 1990s. One main reason OHV engines have lower redlines is valve float. At high speeds, the valve spring simply cannot keep the tappet or roller on the camshaft. After the valve opens, the valve spring does not have enough force to push the mass of the rocker arm, push rod, and lifter down on the cam before the next combustion cycle. Overhead cam engines eliminate many of the components, and moving mass, used on OHV engines. Lower redlines, however, do not necessarily mean low performance, as some skeptics sometimes assume. For example, a Supercharged Buick 3800 V6 with a redline anywhere from 5500-6000 has a torque curve that peaks at 2600-3600rpms, yet the engine is a strong performer from takeoff all the way through to the redline.

Motorcycle engines can have even higher redlines because of their comparatively lower reciprocating mass. For example, the Honda CBR250RR has a redline of about 19,000 rpm. (Though due to regulations in Japanese motorcycle manufacturing this was later lowered to 18,000) Higher yet is the redline of a modern Formula One car. Regulations in 2010 limit the maximum engine rotation to 18000 rpm [1], but during the 2006 season, engine speeds reached over 20000 rpm on the Cosworth engine.

Rev limiter and implementation [link]

The actual term redline comes from the red bars that are displayed on tachometers in cars starting at the rpm that denotes the redline for the specific engine. Operating an engine in this area is known as redlining. Straying into this area usually does not mean instant engine failure, but may increase the chances of damaging the engine.

Most modern cars have computer systems that prevent the engine from straying too far into the redline by cutting fuel flow to the fuel injectors/carburetor or by disabling the ignition system until the engine drops to a safer operating speed. This device is known as a rev limiter and is usually set to an RPM value at redline or a few hundred RPM above. Most Electronic Control Units (ECUs) of automatic transmission cars will upshift before the engine hits the redline even with maximum acceleration (The ECU in a sports car's automatic transmission will allow the engine to go nearer the redline or hit the redline before upshifting). If manual override is used, the engine may go past redline for a brief amount of time before the ECU will auto-upshift. When the car is in top gear and the engine is in redline (due to high speed), the ECU will cut fuel to the engine, forcing it to decelerate until the engine begins operating below the redline at which point it will release fuel back to the engine, allowing it to speed operate once again.

However, even with these electronic protection systems, a car is not prevented from redlining through inadvertent gear engagement. If a driver accidentally selects a lower gear when trying to shift up or selects a lower gear than intended while shifting down (as in a motorbike sequential transmission), the engine will be forced to rapidly rev-up to match the speed of the drivetrain. If this happens while the engine was at high rpms, it may dramatically exceed the redline. For example, if the operator is driving close to redline in 3rd gear and attempts to shift to 4th gear but unintentionally puts the car in 2nd by mistake, the transmission will be spinning much faster than the engine, and when the clutch is released the engine’s rpm will increase rapidly. It will lead to a rough and very noticeable engine braking, and likely engine damage. This is often known as a 'money shift' because of the likelihood of engine damage and the expense of fixing the engine.

Examples of performance automobile piston engines [link]

Examples of production rotary engines [link]

  • Mazda RX-8 1.3L twin rotor 9000 rpm (rev limiter 9400 rpm)

Examples of motorcycle engines [link]

References [link]

  1. ^ Car and Driver Magazine: Glossary of Terms - Redline

https://wn.com/Redline

Redline (video game)

Redline is a video game for Mac OS X developed by Jonas Echterhoff and published by Ambrosia Software. The game's primary features are its ability to simulate actual racing physics, online play, and support for the addition of third party content via plug-ins. The combination of these features have attracted numerous players and led to the creation of a seasonal racing league. Redline also has several modes of gameplay for those who prefer arcade style physics commonly found in other racing games. The game is now currently obsolete and an error message will be displayed upon opening the application as of OS X Snow Leopard and above.

Gameplay

Players may race in one of four modes: Time Trial, Quick Race, Challenge, or Multiplayer. In all of these modes, except for Challenge, the player may choose the track, their car, the weather, forward or reverse orientation, and the physics mode to race under. The modes available are: Simulation, Strict, Arcade, and Turbo Arcade. In Simulation, every car handles differently based on weight, drivetrain, horsepower, suspension setup, and other variables. Strict is a derivative of the Simulation mode, that was added in a later update that adjusts how car-scenery collisions are handled to help reduce the effectiveness of the "wall riding" technique. Arcade sacrifices realism for playability. Cars in Arcade differ less in performance than they do in Simulation or Strict. Turbo Arcade has the same physics as Arcade, but all cars much faster than normal, resulting in the least realistic method of play.

Read more
This page contains text from Wikipedia, the Free Encyclopedia - https://wn.com/Redline_(video_game)

Redline (1999 video game)

Redline is a 1999 post-apocalyptic combination first-person shooter/racing video game for Microsoft Windows. It was developed by Beyond Games and published by Accolade. In Europe, the game is known as Redline - Gang Warfare: 2066. This was the last game Accolade published before being acquired by French publisher Infogrames. Tommo Inc. purchased the rights to this game and digitally publishes it through its Retroism brand in 2015.

The Story

The game plays in a fictitious world set in the twenty-first century, fifty years after the Golden Age of Technology. The world is divided into people who live on the "inside" and gangs who live "outside".

In the 1950s, a person named Reich discovered a source of energy he termed "orgone" and built boxes called orgone accumulators. People who bought them said they cured diseases and made them think more clearly, but most people thought it was a hoax. Scientists wouldn't look at it because Reich was a psychologist, but he sold plans for the boxes to lots of people. At the time no one really understood what happened, but all of a sudden Reich was put in prison and public burnings of his books were held in cities all over the country. Around the turn of the century, people figured out why.

Read more
This page contains text from Wikipedia, the Free Encyclopedia - https://wn.com/Redline_(1999_video_game)

Podcasts:

Email this Page Play all in Full Screen Show More Related Videos
PLAYLIST TIME:
×
×
×
×