A Engine Question.

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BRIAN

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After looking at the forum I can see that a lot of you have nothing to do, so to save you getting bored I will drag up a question i raised on this forum when the numbers were less than 1000.

The engine in question is a Commer TS3 a 3 cylinder 2 cycle diesel

In the last stages of its development before G M pulled the plug , the makers of the fuel pump CAV
developed a version of their DPA distributor pump for this engine.

Now??? the pump ran at half engine speed Not at engine speed as normal ???

So how was it done???

Thinking caps On, Unless you know!!!!!!

Brian.:nuts:
 
On the right track But how???
Brian.
 
I'm guessing they drove it off of the idler gear. That is the only thing in there with a 2:1 ratio. Not sure if that is part of the accessory drive system or not.
 
My first thought was DUH...it runs off the camshaft...diesel engines still have camshafts, right?


Then I realized, 4 cycle diesels have camshafts, but there are no valves and therefore no camshaft in a 2 cycle engine.

It could still be done essentially the same way though - v-belt and pulley drive with the pulley on the fuel pump twice the size of the pulley on the crankshaft.
 
OK we have some interest.
So I will start by clearing up the points raised.
On this engine the pump was driven from the gear train that ran the supercharger ( ported 2 cycle diesels use a big blower to push out the gases and refill with clean air, By closing the exhaust ports early we get supercharging for free). so it is simply a 2-1 reduction by gears.

But the question I am asking is how do get a distributor pump running at 1/2 speed to put out the fuel pulses at engine speed.

If you think of a 3 cyl distributor for a petrol engine , one turn gives 3 sparks, how do you make it give 6 sparks ( 2 turns output ) when you have only turned it Once???

On the Point made about camshafts, Yes some 2 cycle Diesel engines do have valves on the exhaust side operated at engine speed, and ports on the inlet. GM -- Foden --etc, but this is not the question.
Brian.
 
The pump was probably a stock 6 cylinder unit that simply tied every other port together, allowing two injection pulses for every rotation of the pump shaft.
 
Creeping up on it,

The pumping system was 6 cylinder, but the ports are not together.

So how do we take 6 injection pulses and distribute them to 3 outlets at twice the rate.

If it helps think of a 6 cylinder petrol engine distributor, but the cap only has 3 leads.

Brian.
 
No takers I think it's time for a hint .

The out put of this pump is opposite to the rotation . no gears are used the distributor shaft runs in one direction but the output is contrary at twice the speed???

I will offer a free down load of my Beginners clock book to the first person who in my opinion gets the correct answer.

Offer closes on September 1st.

Brian.:think1:
 
Maybe throw lever type deal. Cam type lob to trip it and the pivot would throw the other in the opp direction?
 
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