If you have read the article How the car engines, you know about the valves that allow air / fuel into the engine and the exhaust pipe of the engine. The camshaft uses lobes (called cams) that push against the article you can see the animation that we built to really show the difference between a performance camshaft and a standard.
In this article, you will learn how the camshaft affects engine performance. We have some great animations that show how different engine designs, such as single overhead camshaft (SOHC) and double overhead camshaft (DOHC), really work. And then we'll go over some of the ways that some cars ordered fit the camshaft so that it can handle different engine speeds more efficiently.
Let's start with the basics.
Camshaft Basics
The key parts of any camshaft are the lobes. As the rotations of the camshaft lobes open and close the intake and exhaust valves in time with the movement of the piston. There is a direct relationship between the shape of the cam lobes and the manner in which the engine operates in different speed ranges.
To understand why this is so, imagine that we are running an engine extremely slowly - at just 10 or 20 revolutions per minute (RPM) - to have the piston of a couple of seconds to complete a cycle. It would be impossible to actually run a normal engine this slowly, but let's imagine that we could. At this speed, we would like cam shaped so that:
As the piston begins to move downward in the intake stroke (called a top dead center or TDC), the intake valve open. The intake valve closes as funds right piston out.
The exhaust valve opens on the right as funds piston out (called bottom dead center, or BDC) at the end of the combustion stroke and would close as the piston completes the exhaust stroke.
This configuration may work well for the engine, provided that ran at this speed very slow. But what happens if you increase the RPM? We'll see.
By increasing the RPM, the configuration of 10-20 RPM for the camshaft does not work well. If the engine is operating at 4000 RPM, the valves are opened and closed 2000 times each minute, or 33 times every second. At these speeds, the piston moves very quickly, so that the air / fuel running into the cylinder moves very quickly too.
When the intake valve opens and the piston begins its intake stroke, the air / fuel intake runner begins to accelerate the cylinder. At the time the piston reaches the bottom of its intake stroke, the air / fuel is moving at a fairly high speed. If we were to close the intake valve, all air / fuel would come to a stop and
The following animation shows how a regular camera and have different performance cam valve timing. Note that the cycles of the exhaust gases (red circle) and consumption (blue circle) overlap much more on cam performance. Because of this, cars with such cam tend to run very nearly idling.
Two different cam profiles: Click the button below the play button to switch between cameras. The circles animation.
Any given camshaft will be perfect only one engine speed. At each engine speed, the engine does not operate at its full potential. A camshaft is fixed, therefore, is always a compromise. For this reason, auto manufacturers have developed schemes for varying the cam profile as the engine speed changes.
There are many different modalities camshaft in engines. Let's talk about some of the most common. You've probably heard the terminology
0 Komentar untuk "Camshafts Working"