Engineering Would the two stroke spark ignition PV digram be same as for a 4 stroke?

[lee123456789]

Homework Statement

write about engines

Relevant Equations

none

Would two stroke spark ignition PV digram be same as 4 stroke spark ignition. both have otto pv diagrams.

 

[Chestermiller]

What research have you done on this so far?

 

[lee123456789]

What research have you done on this so far?

ive write about everything just getting confused on the PV diagrams pics to put into the document. i think its otto pv diagram.

 

[jack action]

How many strokes can you identify on the diagram in the OP?

 

[lee123456789]

How many strokes can you identify on the diagram in the OP?

I was thinking on the diagram
stages 1 -2 - 3 compression and 3 -4 - 1 was expansion

 

[jack action]

A stroke is a displacement $V_s$. From 2 to 3 and 4 to 5, there are no displacements (constant volume), so let's forget about those for the moment. But you are correct with 1-2 for compression and 3-4 for expansion. But what about 0-1 and 5-0?

 

[lee123456789]

A stroke is a displacement $V_s$. From 2 to 3 and 4 to 5, there are no displacements (constant volume), so let's forget about those for the moment. But you are correct with 1-2 for compression and 3-4 for expansion. But what about 0-1 and 5-0?

would 2 -3 be ignition phase and 4 - 5 would heat rejection?

0 - 1 Intake Stroke?
5 - 0 Exhaust Stroke?

 

[jack action]

2-3 would be combustion and 4-5 would be heat rejection (or cooling), but that doesn't have anything to do with our strokes.

0 - 1 Intake Stroke?
5 - 0 Exhaust Stroke?

So now you have identified a total of 4 strokes. I guess this is good for a 4-stroke engine PV diagram.

How would a 2-stroke engine PV diagram differ?

 

[lee123456789]

2-3 would be combustion and 4-5 would be heat rejection (or cooling), but that doesn't have anything to do with our strokes.

So now you have identified a total of 4 strokes. I guess this is good for a 4-stroke engine PV diagram.

How would a 2-stroke engine PV diagram differ?

There would just be a compression stroke and expansion stroke and the exhaust would be in included in the compression stroke and intake would be included in compression stroke?

 

[lee123456789]

There would just be a compression stroke and expansion stroke and the exhaust would be in included in the compression stroke and intake would be included in compression stroke?

2-3 would be combustion and 4-5 would be heat rejection (or cooling), but that doesn't have anything to do with our strokes.

So now you have identified a total of 4 strokes. I guess this is good for a 4-stroke engine PV diagram.

How would a 2-stroke engine PV diagram differ?

I think this would be the sequence of 2 stroke

0 to 1 intake phase
1 to 2 compression stroke
2 to 3 ignition phase
3 to 4 expansion stroke
4 to 5 heat rejection phase
5 to 0 exhaust phase

 

[jack action]

Post #9 is good, post #10 is wrong, or at least confusing. The intake phase (0-1) and exhaust phase (5-0) will not appear on the PV diagram as they will be included in the compression and expansion strokes. They are only 2 strokes.

 

[lee123456789]

Post #9 is good, post #10 is wrong, or at least confusing. The intake phase (0-1) and exhaust phase (5-0) will not appear on the PV diagram as they will be included in the compression and expansion strokes. They are only 2 strokes.

I think this is it

0 to 1 to 2 to 3 compression stroke - included intake phase, compression stroke and ignition phase.

3 to 4 to 5 to 0 power stroke - includes power stroke, heat rejection, and exhaust phase

 

[jack action]

There are no 0 to 1 nor 5 to 0 lines drawn on the PV diagram. That is the difference between the 2-stroke and the 4-stroke PV diagrams. The 2-stroke has only 4 points:

Both the intake & exhaust phases will begin somewhere between 3 and 4 and end somewhere between 1 and 2.

Versus a 4-stroke engine PV diagram:

 

[lee123456789]

There are no 0 to 1 nor 5 to 0 lines drawn on the PV diagram. That is the difference between the 2-stroke and the 4-stroke PV diagrams. The 2-stroke has only 4 points:

View attachment 284433​

Both the intake & exhaust phases will begin somewhere between 3 and 4 and end somewhere between 1 and 2.

Versus a 4-stroke engine PV diagram:

View attachment 284434​

Sorry could u layout the strokes eg 1 to 2 to 3.
Sorry for being thick.1 to 2 to 3 I take, compression stroke and ignition.

3 to 4 to 1. Power stroke, heat rejection and exhaust.

 

[jack action]

If you look at the 4-stroke engine PV diagram in my last post, a downward stroke is from TDC (top dead center) to BDC (bottom dead center) and an upward stroke is from BDC to TDC. The same limits applied to a 2-stroke engine.

 

[jack action]

 

[lee123456789]

View attachment 284436​

Thank u and sorry for being that dang at it
Diagram helped.