Fuel Temperature

[skipperdude]

I was reading that there is a major power loss if diesel fuel reaches 100Deg.

Has anyone noticed an issue with hot fuel.

SD

 

[RickB]

skipperdude wrote:
I was reading that there is a major power loss if diesel fuel reaches 100Deg.

Where were you reading that?

If you want to get down to basics, it doesn't make any power at all until it reaches over 400*F.

The density of fuel decreases with increasing temperature so if the volume remains the same, the number of BTUs available in a gallon (for instance) at 100 degrees is less than it is at the standard 60 degrees.

The amount of energy per unit of weight remains the same, it just takes more volume of hot fuel to provide the same weight.

The engine only knows if it is getting enough weight of fuel to maintain the rpm set by the governor. If the fuel is hot, it will tell the injector pump to put in a larger volume of fuel to supply the weight it needs to maintain rpm.

The only way there could be a power loss is if the engine was running up against the governor fuel stop (not speed stop) and the fuel temperature increased.

By the time your fuel reaches the injector nozzle it is far above 100 degrees but the fuel system compensates so that you never even know the difference.


-- Edited by RickB on Friday 23rd of December 2011 10:27:41 AM

 

[skipperdude]

I was reading a Cat maintenance manual reguarding fuel temp and fuel heaters for cold weather. I can't quote right now as I don't have the book with me. I see what you are saying. It could be I read it wrong and it was refering to fuel consumption vs power output.

Thats what I get for doing things from memory. I should delete this tread untill I have the literature in front of me.

SD

 

[RickB]

skipperdude wrote:I should delete this tread untill I have the literature in front of me.

No, don't do that, every question answers something for somebody.

CAT's note was that if you use a fuel heater in very cold weather but let the fuel get too hot, the viscosity can drop too much and you can lose power.

Too low a viscosity accelerates wear in the fuel injection pump and injectors. Too hot a fuel can create vapor bubbles and cause cavitation in the injector pump that creates a great deal of wear and since vapor displaces fuel, it is just like reducing the amount of fuel being injected so the engine loses power.

Don't worry about it unless you wrapped your fuel line around the dry stack a few times to make a really skookum fuel heater.

https://safety.cat.com/cda/files/715418/7/Cold+Weather+Recommendations+For+all+Machines.pdf

Page 19

-- Edited by RickB on Friday 23rd of December 2011 11:14:33 AM


-- Edited by RickB on Friday 23rd of December 2011 11:15:37 AM

 

[markpierce]

skipperdude wrote:
Has anyone noticed an issue with hot fuel.

*No, little chance of such a high temperature with the local waters at 50 degrees.