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Topic: ** HELP ** Engine Speed Signal Outputs for Crankshaft and Camshaft Sensors (Read 974 times) previous topic - next topic

Robin2

I've attached a drawing
Please post the drawing as a JPG or PNG file and make it visible in your Post so we don't have to download it. See this  Simple Image Posting Guide


Quote
Well, for the crankshaft it would be 60 pulses per revolution. I would guess we could just base the camshaft pulses off of the crank's and say 60 also for the camshaft?
I can't see you getting very far with "I would guess". If you want to emulate a real engine then you need to know what is required.

...R
Two or three hours spent thinking and reading documentation solves most programming problems.

samirakle

Please post the drawing as a JPG or PNG file and make it visible in your Post so we don't have to download it. See this  Simple Image Posting Guide

I can't see you getting very far with "I would guess". If you want to emulate a real engine then you need to know what is required.

...R
Alright, I'll rephrase then: Since the crankshaft is comprised of a total of 60 equal spaces, each camshaft rotation should also be divisible by the same number of pulses or sections.

Here's the picture:

Crank_Cam_Signals

Robin2

Image from Reply #31 so we can see it. See this  Simple Image Posting Guide



...R
Two or three hours spent thinking and reading documentation solves most programming problems.

Robin2

Since the crankshaft is comprised of a total of 60 equal spaces, each camshaft rotation should also be divisible by the same number of pulses or sections.
Let's accept that for the moment.

Next question, the graph shows 5 cam pulses between each double pulse but the cam double pulse does not always happen at the same point in the crank revolution. What is generating the cam pulses?

...R
Two or three hours spent thinking and reading documentation solves most programming problems.

samirakle

Let's accept that for the moment.

Next question, the graph shows 5 cam pulses between each double pulse but the cam double pulse does not always happen at the same point in the crank revolution. What is generating the cam pulses?

...R
Hi there. I'm not sure what you're referring to as the "double pulse", sorry. Could you possibly mark the area you're speaking of if possible?

There's a timing rotor located in the middle of the camshaft that's generating the pulses. You'll need to refer to post #9 to get an idea of what it looks like.

Robin2

Hi there. I'm not sure what you're referring to as the "double pulse", sorry. Could you possibly mark the area you're speaking of if possible?
It seems very obvious to me and it was a real PITA to make this image



...R
Two or three hours spent thinking and reading documentation solves most programming problems.

samirakle

#36
Jun 29, 2020, 11:07 pm Last Edit: Jun 29, 2020, 11:10 pm by samirakle Reason: Adding attachment photo.
It seems very obvious to me and it was a real PITA to make this image



...R
Yep, it was an even bigger PITA for me to draw out the signals as best as possible. Anyway, thanks for marking that because I would've never been able to make that "double pulse" connection with that area.

Keep in mind that we have 1 short, 1 medium, and 5 long pulses with the camshaft.


I made a minor mistake in my drawing that I just noticed. Here's an updated version of it:




Robin2

Anyway, thanks for marking that because I would've never been able to make that "double pulse" connection with that area.
I'm struggling to understand your confusion. I realize that what I called a double pulse you might call a double trough - but I can't see that that would have prevented you identifying it.

I'm only focusing on this because I feel that sorting out our common understanding might make it easier for us to communicate effectively in the future.

And you have not explained why the double is not always in the same position relative to the crankshaft pulses.


Another question. There is a short gap between the groups of crankshaft pulses. How many pulses are there between each gap and what is the duration of the gap in terms of the number of missing pulses?

...R
Two or three hours spent thinking and reading documentation solves most programming problems.

samirakle

#38
Jun 30, 2020, 08:31 pm Last Edit: Jun 30, 2020, 08:33 pm by samirakle Reason: Adding attachment for picture.
I'm struggling to understand your confusion. I realize that what I called a double pulse you might call a double trough - but I can't see that that would have prevented you identifying it.

I'm only focusing on this because I feel that sorting out our common understanding might make it easier for us to communicate effectively in the future.

And you have not explained why the double is not always in the same position relative to the crankshaft pulses.


Another question. There is a short gap between the groups of crankshaft pulses. How many pulses are there between each gap and what is the duration of the gap in terms of the number of missing pulses?

...R
Hi there,

Yes, I'm trying to get us on the same page here as best as possible. Thanks for being patient with me.

Alrighty, so the "double" is in the same position in relation to the crankshaft pulse teeth for every rotation. I've added notation showing that the 27th crank tooth of the crankshaft is where the "double" begins on 2 consecutive camshaft cycles.



Are you asking about the short low gaps between the camshaft pulses? If so, the gaps would consist of this sequence of crankshaft pulses: 1 LOW, 1 HIGH, 1 LOW, 1 HIGH, 1 LOW.


Robin2

Alrighty, so the "double" is in the same position in relation to the crankshaft pulse teeth for every rotation
It is different on the top row of your image.

Quote
Are you asking about the short low gaps between the camshaft pulses?
No. I specifically said "crankshaft pulses"

...R
Two or three hours spent thinking and reading documentation solves most programming problems.

samirakle

It is different on the top row of your image.
Both of the signals I've drawn at the top of the image are not in sync with each other. I simply just drew the signals out so that I could use them as a template to copy and paste at the bottom of the image.

No. I specifically said "crankshaft pulses"
In that case we can think of there being 120 total individual "gaps" since there are 60 high pulses.

Robin2

In that case we can think of there being 120 total individual "gaps" since there are 60 high pulses.
We seem still to be completely failing to communicate.

Just considering the line of crankshaft pulses on its own ...

I see a lot of pulses close together and then a short gap and then another run of pulses close together. It is the length of the short gap between the runs of pulses that I am interested in. How many pulses are there in the run of pulses and how many are missing during the short gap between runs?

I am assuming that the gap between the runs of pulses signifies the completion of 1 revolution - is that correct?

...R
Two or three hours spent thinking and reading documentation solves most programming problems.

samirakle

Just considering the line of crankshaft pulses on its own ...

I see a lot of pulses close together and then a short gap and then another run of pulses close together. It is the length of the short gap between the runs of pulses that I am interested in. How many pulses are there in the run of pulses and how many are missing during the short gap between runs?

I am assuming that the gap between the runs of pulses signifies the completion of 1 revolution - is that correct?

...R
Crankshaft has 57 small teeth and 1 wide tooth equivalent to the width of 3 small teeth for a total of spacing for 60 small teeth.

Yes, 1 full revolution of the crankshaft is from 1 wide tooth to the next.

Robin2

Crankshaft has 57 small teeth and 1 wide tooth equivalent to the width of 3 small teeth for a total of spacing for 60 small teeth.
Thank you. That's what I wanted to know.

Supposing that you treat the first tooth after the wide tooth as Number1 - then at what tooth positions does each rising camshaft pulse occur?

...R
Two or three hours spent thinking and reading documentation solves most programming problems.

samirakle

Thank you. That's what I wanted to know.

Supposing that you treat the first tooth after the wide tooth as Number1 - then at what tooth positions does each rising camshaft pulse occur?

...R
So that drawing that I provided is accurate to the exact crankshaft tooth that each sized camshaft tooth should begin at. I've marked the 27th, 32nd, and 47th teeth of the crankshaft signal to designate where the short, medium and 1st long pulse should begin, respectively.

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