# how many power stroke in 3 cylinders, 4 stroke at 3000 rpm?

According to some answers, in 3 cylinder , 4 stroke we have power stroke each 240°, as we have 1500 rev. Of 720° in this rpm, so we will have this: 1500 x 1.5 = 2250 power stroke at 3000 rpm, is it right?

A 1 cylinder 4 stroke at 3000 rpm will have 1500 power strokes,

So 1500 * 3 is 4500 power strokes.

Based on a 4 stroke engine needing two crank revolutions to complete the full cycle of intake, compression, power and exhaust.

• A single cylinder engine will have one power stroke every two rotations.
• At 3,000 RPM it will have 1500 power strokes.
• A three-cylinder engine will have 3 × 1500 = 4500 power strokes per minute.

Where did you go wrong?

... we have power stroke each 240°, ...

OK so far.

... as we have 1500 rev. Of 720° in this rpm, ...

An odd way of looking at it, but OK.

so we will have this: 1500 x 1.5 = 2250 power stroke at 3000 rpm?

No, you'll have $$1500 \times \frac {720}{240} = 1500 \times 3 = 4500$$.

• This is not part of your question so it is unfair of you to ask me to answer it in the comments. Either edit it into your question or post a new question with a link to this one. When you do you need to explain why you are comparing RPM with L/s. 4500 RPM $\neq$ 3000 L/s. They are not directly comparable and you have arbitrarily picked a 2 L capacity. If you had picked a 3 L capacity engine you would have got 4500 L/s. Would you have been happy then? – Transistor Feb 11 at 20:47
• Above comment is a response to OP's deleted comment. – Transistor Feb 11 at 20:53
• No problem. It's unfair because you are expanding the scope of your question which has already has two answers. There was nothing about air-intake in the question or in my answer. – Transistor Feb 11 at 20:57
• Just post a new question. You'll get a variety of answers that will give you several ways of looking at the problem and solving it. – Transistor Feb 11 at 21:10
• Don't change the question. You have two answers to the original question and you'll make them look stupid. You can do an edit and put an EDIT heading before it so that readers realise that you've updated the question. Your question isn't even a full sentence at the moment. – Transistor Feb 11 at 21:40