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Bigbadspoon · 09-16-2010, 10:32 PM

Hi all. Been a while since I posted, but I'm in my junior year in mechanical engineering and just finished discussing junior/senior design projects with one of my professors. We refined the idea down to a project on using waste heat to power some sort of steam engine (quasiturbine, cyclone, something cheaper?) but one of the hurdles we want to overcome is the operating temperature of the radiator.

That being said, yes, the exhaust is fairly fertile ground for harvesting heat, but the coolant is easier to control the flow for a heat exchanger, though the final product may well cover both.

Anyway, we'll be using my Honda Civic, which operates around 195 degrees F, which is simply not hot enough to boil pure water. We discussed raising the operating temperature to a higher level, but can't find any specific data on just exactly how this will affect engine life. Thermal expansion and reduction of oil viscosity would be the key things to look at, however we're aiming for something like 220-240 degrees. Incidentally, if we raise the engine temp, overall efficiency should increase because of the difference in exergy and all

From what I know of the aluminum and steel, their coefficients of thermal expansion are relatively small, especially for a change of only 30-50 degrees F. So, I don't think that will really be an issue of concern.

Has anyone seen data regarding the loss of oil life at temp? I've seen some viscosity figures like SAE 30 at 190F is about the same viscosity as SAE 40 at 240 degrees or some such, but nothing about breakdown or even multi-viscosity oils. We are in FL, so multi-viscosity is not critical as the ambient temp is rarely below 50 degrees, but I'd still feel better having that option.

Of course, if all else fails, we may just use the radiator as a warmer and send the near-boiling water over a specially constructed exhaust manifold/heat exchanger.

But I would love to get some input from you guys about the overall idea, as well as any pertinent information you may have regarding oil life vs engine temp.

09-16-2010, 10:32 PM	#1 (permalink)
Bigbadspoon EcoModding Lurker Join Date: Feb 2008 Location: Florida Posts: 17 Thanks: 0 Thanked 1 Time in 1 Post	Engine Temp and wear Hi all. Been a while since I posted, but I'm in my junior year in mechanical engineering and just finished discussing junior/senior design projects with one of my professors. We refined the idea down to a project on using waste heat to power some sort of steam engine (quasiturbine, cyclone, something cheaper?) but one of the hurdles we want to overcome is the operating temperature of the radiator. That being said, yes, the exhaust is fairly fertile ground for harvesting heat, but the coolant is easier to control the flow for a heat exchanger, though the final product may well cover both. Anyway, we'll be using my Honda Civic, which operates around 195 degrees F, which is simply not hot enough to boil pure water. We discussed raising the operating temperature to a higher level, but can't find any specific data on just exactly how this will affect engine life. Thermal expansion and reduction of oil viscosity would be the key things to look at, however we're aiming for something like 220-240 degrees. Incidentally, if we raise the engine temp, overall efficiency should increase because of the difference in exergy and all From what I know of the aluminum and steel, their coefficients of thermal expansion are relatively small, especially for a change of only 30-50 degrees F. So, I don't think that will really be an issue of concern. Has anyone seen data regarding the loss of oil life at temp? I've seen some viscosity figures like SAE 30 at 190F is about the same viscosity as SAE 40 at 240 degrees or some such, but nothing about breakdown or even multi-viscosity oils. We are in FL, so multi-viscosity is not critical as the ambient temp is rarely below 50 degrees, but I'd still feel better having that option. Of course, if all else fails, we may just use the radiator as a warmer and send the near-boiling water over a specially constructed exhaust manifold/heat exchanger. But I would love to get some input from you guys about the overall idea, as well as any pertinent information you may have regarding oil life vs engine temp.