File talk:4-Stroke-Engine.gif

potřeboval bych maturitní projekt!!! kdo se nabýdne?! —the preceding unsigned comment is by 82.114.193.186 (talk • contribs)

Warnings & Comments

Comment: There is no space left at TDC -> verry high compression. 1:10 is usual.

Warning: This animation is not completely accurate. There should be some space left when the piston is at its highest position. The current animation suggests infinite compression.

Comment: This is a 2D projection of a 3D model. The little space went lost in the pixels of the outlines. And a 2D projection is not able to show the space around the "roof" of the piston. (UtzOnBike) --85.182.123.226 20:58, 11 October 2006 (UTC)

Comment: Ignition of the air-fuel mixture does not occur exactly at TDC, rather a short time before the piston reaches Top Dead Center. This is commonly referred to as BTDC and is expressed in a number of degrees of the crankshaft rotation, i.e. 8 degrees BTDC.

The ignition point varies with engine rpm. An engine rotating at such a slow speed as the one in the animation would definitely not fire at 8 degrees BTDC. IJB_TA

Comment: It would be nicer to show the intake and exhaust by moving clouds instead of the abrupt colour changes.84.210.139.189 17:46, 18 February 2007 (UTC)

If you don't like it make a new one. IJB_TA

Comment: I removed "injected" from the Description because this does not appear to be a fuel-injected motor.84.210.139.189 17:46, 18 February 2007 (UTC)

Why do people feel the need to endlessly criticize this animation? It shows the 4 stroke cycle VERY clearly, what else do you want? IJB_TA

Comment: Hear, Hear!!! Why don't these whiners try making this animation?--68.229.100.176 03:57, 17 November 2007 (UTC)

I agree with the person above my comment. The picture is an excellent example of a four strike engine. Anyone who did try to make a diagram would fail miserably.17:20, 27 February 2007 (UTC)Vinaq

Hey Vinaq, is it a good exaple of a four-strOke engine then too! Oh and I reckon arrows would be ace too. Amt

Hi...I agree with you IJB_TA & Amt. The main point is to demonstrate visually what is a 4 STROKE CYCLE like. Great work UtzOnBike! *zaidi*

This animation helped me a lot to understand. Thanks!

The image itself is quite clear and straight forward. RE comments about ignition timing: timing is divided into base and dynamic timing; dynamic timing is altered as a function of engine speed and load. That being said, it is still quite common to consider the spark to ignite the fuel just prior to the power stroke. Some engines are base timed at 0 degrees; some (very few) are actually timed AFTER TDC. Also, remember that ineffective crankshaft throw means that the piston has practically ended its upward travel by the time 10 degrees BTDC has occurred.

RE comments about injection: it is impossible to determine that the engine is not fuel injected. It is possible to ascertain that it is not port injected and it is not direct injection, however, recall that many engines used single point fuel inejection systems such as GM TBI (used right up until the bitter end!) Ford CFI, Honda DPFI and Chrysler EFI. If you look at some of the modern motorycle engines they use a similar method: a multec style injector at the throttle body rather than directly in front of the intake valve. This allows a longer period of air fuel blending and reduced intake valve coking.

RE clearance volume comments: I believe that the engine animation is designed to express the Otto cycle, not engine mechanical limitations. I think that it is well done.