more questions 12/04/11

1.What is the firing order of a four stroke engine?
- the firing order is the sequence in which the pistons do their power stroke. for a four stroke engine the sequence is in order of pistons -1-3-4-2-. 

2.What is the difference between a S.I and C.I engine?
- S.I ENGINE = spark plug ignition. 
- C.I ENGINE = diesel compression ignition. 

3.Is there any difference between a S.I and C.I piston if so what?
- yea the C.I engines pistons have to made to withstand the higher compression and heat. they tend to be larger and have a different shapped crown to the S.I pistons.

  S.I piston

 C.I piston

4.What year was the diesel engine invented and by whom?
- the inventor of the diesel engine was Rudolf Diesel and he invented it in the 1890's

5.What is the purpose of the oil jet on the connectng rod, and where does it spray?
- when the piston travels up to T.D.C the preasurised oil is sprayed up onto the thrust side of the piston so that it lubricates the bore for when the piston travel backs down to B.D.C.

6.On the connecting rod where is the big end and little end?
- the small end of the connecting rod is connected to the piston head and the big end of the connection rod is connected to the crankshaft.

7.What is the purpose of the thrush washers on the crankshaft?
- they prevent the play of the crankshaft from moving to much. but the crankshaft must have a small amount of play to be able to move the pistons properly.

8.On a diesel engine whats the difference between direct injection and a indirect injection type?
- the indirect injection works so that the fuel mixture is not injected straight into the combustion chamber but is injected into a prechamber that then combusts and follows through into the main combustion chamber, were as the direct injection just injects the fuel mixture directly into the main combustion chamber to combust.

9.Explan the term valve timming?
- valve timing is what the name says. its the timing in which the valves for the air intake and exhaust that lead to and from the combustion chamber, are opened and closed. this has to be very presise to make the engine run properly.

10.Why do we have valve clearance?
-