Fuel and oil system questions

[willisdaye]

I'm using propane to power a turbocharger engine. Do I need a regulator? My plan is to connect the fuel rail to the gas canister using a propane hose secured with a hose clamp, and have a ball valve behind it to control the flow of fuel. Diagram attached. Will this work safely, or will I need a regulator?

Diagram

My other question is about the oil system. Will those braided steel hot/cold water hoses from the hardware store work for hot oil?

[racket]

Hi

No regulator needed , use the cylinder valve for control and your ball valve for a quick shutdown safety .

If the turbo is "small" , a comp wheel inducer <2" - 50 mm diameter , then you may need a finer control needle valve included in the system to provide better control than the large cylinder valve can provide.

Do NOT have any sort of propane hose anywhere near the engine , heat from the engine will degrade it and a fireball could be the outcome , use metal tubing with the correct fittings, hose clamps are for drain lines where theres no pressure involved

As for the braided water hoses , the rubber inner might not cope with hot oil , again use metal tubing for any pressure line , hot oil spraying onto a red hot turbine scroll and you'll have another fireball ...............safety first :-)

Cheers
John

[willisdaye]

Thanks for the info. I have a decent amount of the iron pipe, would that original design be safe if the pipe extended away from the engine and then turned 90 degrees, extended a bit, and then ended with the hose fitting?

[racket]

It'd be better .

But please be careful with "soft" plumbing .

Cheers
John

[smithy1]

Agree totally with John....be sure to "over-engineer" everything.

You only need a millisecond of "blowback" to destroy a flexible line which is not designed for the purpose..... and as John says, it can turn very nasty, very quickly. If possible, use correctly rated stainless braided fuel lines near hot parts where a hard line is not feasible or possible.

Cheers,
Smithy.

[willisdaye]

Yeah there will be over a foot and a half of iron pipe between the engine and the hose section. One more question, how far in the combustor should the fuel sprayer be, and how big should the holes/hole area on the sprayer be?

[smithy1]

Jan 4, 2016 18:05:16 GMT -5 willisdaye said:

Yeah there will be over a foot and a half of iron pipe between the engine and the hose section. One more question, how far in the combustor should the fuel sprayer be, and how big should the holes/hole area on the sprayer be?

Fuel should ideally be introduced just before or at the primary zone, this will help with fuel/air mixing prior to burning between the primary & secondary zone, the further down you introduce the fuel....the further down the flame tube it will travel which is not always ideal.
One thing I have learned from John is that a nice generous, correctly designed flame tube makes things work so much more efficiently with better/smoother combustion.....the one he built for my 6041 powered go-kart is a prime example of this. The original vaporizing tubes in it were well positioned right next to the start of the primary zone and it runs faultlessly with very good acceleration characteristics, even from very low rpm/P2. The flame front is well up the flame tube and there's no evidence of combustion in the tertiary zone. The Rolls-Royce C20B & C30 flame tubes introduce the fuel at the very top of the primary zone....seems to work well for them.

The injector/spray hole sizes and number of them will depend on the fuel requirements for your particular engine. If using liquid fuel, more small holes with high pressure is better than less large holes and low pressure.

Cheers,
Smithy.

[willisdaye]

Thanks guys, ill tell you how it goes.