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Super Contributor

Re: Question about percent of return fuel on different types of Caterpillar engines

Because of the different control types used by CAT over the years I don't think there is any single reference that would help, other than the Caterpillar Application and Installation Guide LEBW4981-Diesel Engine Control Systems, which you can find a copy here,

 

http://www.gregorypoole.com/power/New/Pages/Application-Installation-Guides.aspx   (Thank you Gregory Poole for posting these guides on the web!)

 

The best specific information for each engine is provided in the service manual module "Systems Operation, Testing and Adjusting" for a particular engine family.

 

Hope that helps,  MikeL.

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Re: Question about percent of return fuel on different types of Caterpillar engines

Thanks for this. Was always under impression return was much higher than those pcts. On the electronics, can you direct me to a document that gives some insight to the fuel metering process controlling the injector feed to the engine? Trying to discover how engine would respond to changes in fuel quality that might affect performance and fuel consumption. Also, would a C32 be similar in this respect to something like a 3512B series in the way the fuel dispensing is managed.

Regards,

Mark Phillips

Seattle,WA

 

Super Contributor

Re: Question about percent of return fuel on different types of Caterpillar engines

3300 series engines had very low return rates for for both the compact and new scroll fuel systems, typically around 1-2% of burn rate. 3400 series engines also had low return rates, but higher, at least in my experience, than 3300 series engines, typically around 3-4% of burn rate.

 

Until the introduction by CAT of unit injectors, either MUI, EUI or HEUI, the main function of return fuel flow was deareation, unit injectors require excess fuel flow for cooling. Actual rates vary by design of the installed fuel system but is typically 2-4 times burn rate for most engines.

 

Hope that helps,

 

Mike L.

Visitor

Question about percent of return fuel on different types of Caterpillar engines

Hi, I'm new to this forum and was particularly interested in any documentation or knowledge some of you may have on the volume of return fuel (say as a percent of total supply) that is returned to the fuel tank on engines like the 33, 34 and 35 series. I know old 2-stroke engines like the Detroit '71s and '92s are known for having very high return flow(perhaps as much as 70-90%) to dissapate heat from the engine. Others have told me these Cat engines have a miniscule amount of return fuel. Also does it differ if dealing with a mechanical or electronic form of these engines like the 3412 which comes in both configurations?

Thanks in advance to anyone who can offer any informed answers or references.

Regards,

Mark Phillips