Thursday, May 12, 2011

CrazyEngineers Forum - Mechanical & Civil Engineering

CrazyEngineers Forum - Mechanical & Civil Engineering


Robot base?

Posted: 12 May 2011 05:21 AM PDT

Can anybody suggest some ideas for constructing a robot base?, i am ready with the circuit for the simple line follower robot, but i need a robot base for fixing motors and connecting with the wheel, any ideas?

BAJA SAE India Rule Book Download

Posted: 12 May 2011 04:50 AM PDT

BAJA SAE India's Rule Book for download here:
Attached Files

Engine valve timing diagram

Posted: 11 May 2011 08:03 PM PDT

Hello friends, I always wanted to write something about this on forum.

The topic chosen by me this time is Engine valve timing diagram.

Now what is it exactly? Let us try to learn it in a simple way. :)
See this diagram



I am talking about a four stroke engine. There are four strokes. They are

1. Suction or Intake stroke.
2. Compression Stroke.
3. Expansion this is also called as a power stroke.
4. Exhaust

Now in case of a piston-cylinder arrangement, the valve should open at top dead center and close exactly at bottom dead center. Practically in real world, such ideal cases do not exist.

So if you see the diagram then you will see that the intake valve opens 12 degree 30 min before TDC and it closes 51deg 30min later than BDC.

Similarly the exhaust valve opens 53deg 30 min before BDC and closes 10deg 30 min later to TDC.

Got this much?

Now look at the TDC what do you see? The inlet valve and exhaust valve are open for some time together. This causes a loss in power. It is wasted.

A designer needs to reduce this 12deg30min+10deg 30min=33 deg. overlap to minimum possible (i.e.; 0 degrees) So that we can utilize the power stroke to its fullest.

This is the whole concept of Engine valve timing diagram. What say people?

For any doubts and discussion, I am ready. :p

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