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Power and efficiency versus intake air temperature

Power and efficiency versus intake air temperature

Power and efficiency versus intake air temperature

We have a couple of CAT 1600F gensets powered by their CAT3512B intercooled diesel engines. These are running where the ambient air temperature is 116F. With some additional ducting we are looking at drawing air from outside the building where the air temperature is about 104F. Has anybody got power or efficiency versus intake air temperature for these engines so that we can decide whether it is worthwhile to make the changes.

RE: Power and efficiency versus intake air temperature

Can you provide some specific info on you engines like a serial number? If these are older JWAC aftercooled engines the impact of ambient air temp is much greater, newer engines with SCAC aftercooling usually have a larger margin and are less affected. Also, are these engines in an area with strict air quality requirements?


RE: Power and efficiency versus intake air temperature

Off the top of my head, I believe intake air temperature generally improves power and slightly reduces efficiency. The improved power results from increased air density and the associated increase of air mass in the cylinder which allows more fuel for a given air/fuel ratio. The slight loss of efficiency is due to cooling of the combustion chamber.

RE: Power and efficiency versus intake air temperature

The gen set is relatively new as in 2 years old. The serial number is CAT3512BJYAY01408. The engine has a number of IGZ09077, if that helps.

The gen sets are operating up in Africa where air quality requirements are very lax.

I need to do a cost justification for the modifications therefor I need to quantify the returns on moving the air intake. I was hoping there was a graph available showing power/efficiency at different ambient temperatures which I could use as a basis to work on.

Thanks for you input so far.

RE: Power and efficiency versus intake air temperature

Unless the control system is de-rating the engine because of the temperature, I doubt there will be significant improvement in efficiency or power.

je suis charlie

RE: Power and efficiency versus intake air temperature

Touch base with the local dealer, they will give you everything anyone else can legally provide. There are also forums on the Cat website that are frequented by service engineers who may be able to help.

RE: Power and efficiency versus intake air temperature

At the least you should notice a change in efficiency as the temp varies through the day; see if you can get a mass-flow meter to measure the fuel consumption against intake temp and output power. (I see there is a monitor available that should have this same info.)

However I would expect the additional power to make up for the increased intake length would eat most of the temp-related improvement.

RE: Power and efficiency versus intake air temperature

Your actual serial numbers are, (1GZ09077)-Engine (L1R00699)-Generator (YAY01408)-Genset Package.

From some rule of thumb commissioning info I have for 3500B diesel units, Rated conditions ambient air temperature to the air cleaner is 25 degrees C/77 degrees F.

Power derate based on the performance data (assuming sea level altitude)does not change, however this unit was shipped without a radiator, so I don't know ambient capability of your aftercooler radiator. The performance data for you unit as shipped indicates a rated aftercooler water temp of 86 degrees F, to provide a nominal manifold air temp of 117 degrees F at full load.

Do get an accurate derate calculation I would need to know your full load aftercooler water temp (outlet of cooler/inlet to pump) and the inlet air manifold temp.

I attached a performance data sheet for your reference.

Your local CAT dealer should be able to provide this information for you as well.

Hope that helps, MikeL.

RE: Power and efficiency versus intake air temperature

Thanks for the info, especially Catserveng for the pdf document. The genset is on a mine in Mali and we are based in South Africa. I contacted the local CAT agents who are Barlow Power. They ignored my request for information, probably because they weren't the original equipment suppliers. I then contacted CAT USA who referred me back to Barlow Power, who again failed to respond. I have given up with Barlow Power.

I will have to spend the next few weeks crunching some numbers and see what they say.

RE: Power and efficiency versus intake air temperature

The performance Data Sheet at sea level doesn't start to de-rate till 120°F +.

je suis charlie

RE: Power and efficiency versus intake air temperature

Thanks all for the information

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