Heat Exchanger - Ducati.ms

Sputniks · Oct 7th, 2011, 10:44 pm

After looking at one of the RetroSBK bikes published on the cover of the magazine....
I have noticed an oil radiator (just below the liquid one) that looks "suspiciously" the same as the one found on Ducati Classic bikes.

If the Streetfighter's heat-exchanger is really the oil radiator why then it doesn't look like a radiator. It is positioned in a poorly ventilated area (behind the lower coolant radiator and it is enclosed by the side plastic guards). Aside from a "strange" placement and weird angle its shape is rather interesting too. I am not an engineer but it wouldn't take much to realize that its cooling capabilities must be rather weak:

Compare it to Monster's or Paul Smith Oil Radiators. They look both functional and beautiful (from engineering standpoint) at the same time:

FlyingQ · Oct 7th, 2011, 10:53 pm

I don't think it's a cooler per se. I believe it's actually a heat exchanger used to warm the oil quickly to ensure proper cold-motor lubrication and reduce the chance of a cold seizure. It would also seem to provide for stable oil temps due to the more-or-less constant temp of the coolant being run through it. But, then again, I could be totally wrong also.

The Monster oil coolers you posted are, in fact, oil coolers. But, they are being used on an air cooled engine. With most "air cooled" motors, oil serves two purposes: lubrication, and cooling.

Sputniks · Oct 7th, 2011, 11:08 pm

Very cool. The assumption that the heat-exchanger is used to warm the oil up to an operational temperature quicker is quite interesting. How would it work then? That could be a reason why they called it an "exchanger" and not the cooler or the radiator....

FlyingQ · Oct 7th, 2011, 11:22 pm

This is how I believe the heat exchanger is being used, but like I said, I could be totally wrong. The engine coolant warms up relatively rapidly. It's circulated through the oil heat exchanger to increase the oil temperature to it's normal temp more quickly and provide for stable oil temperature in the normal operating range by providing a medium to transfer heat to and from the oil and coolant. The coolant temp is, of course, controlled by a thermostat and cooled using the two radiators. To some degree, the coolant temperature can be used to stablize/control the oil temp. That's how I see it...

FlyingQ · Oct 8th, 2011, 12:11 am

BTW, the 1098 & 1198 do not have this heat exchanger. They have one coolant radiator and one oil cooler.

Maximmagnum · Oct 8th, 2011, 12:24 am

don't read into the name too much, a radiator is a heat exchanger, just by a different name. A heat exchanger from a thermodynamics standpoint is just a way to transfer energy from one reservoir to another. Sometimes you want to get rid of heat, and sometimes you want to recycle it...don't automatically assume that you want to get rid of it. Many large industrial engines (like a turbine engine on an M1 Abrams main battle tank use heat exchangers to take heat from the exhaust and put that heat back into the air intake before it gets to the engine. This allows it to recycle this otherwise wasted energy, by raising the energy level inside of the incoming air charge...increasing power and fuel efficiency.) For the instance on our motorcycle, I don't know what this heat exchanger does, but FlyingQ's answer sounds quite reasonable, and would necessitate NOT exchanging the unit for an aftermarket part.

cts · Oct 8th, 2011, 3:41 am

flying is right, thats what this heat exchanger does.
it is so much better when it comes to how early you can push the engine when you have a cold start, but has one draw back thought, that it could operate in lower oil temps if it was out getting air, for example when you push the bike on the track....i guess you cant have it all! but i prefer the method the sf s is using to keep the oil in a good temp!

Sputniks · Oct 8th, 2011, 9:25 am

The thermostat's job is to assure the coolant's temperature reaches the operational temperature as early as possible by blocking the coolant from going to water radiators. After the coolant "minimum" temperature is reached the thermostat assures the temp never falls below a minimum threshold.
The reason why the thermostat approach wasn't implemented for the oil could be because there is no oil radiator on Streetfighter to block the oil from going to.
The implementation of the heat-exchanger is to share the coolant/water cooling system with the oil. Instead of cooling the coolant only the system cools the oil too. The limited space is the main reason why Ducati did it this way. Since the front of the bike was already taken by the liquid radiators there was no space left for the oil radiator. Without a heat exchanger there would be no way to control the maximum oil temperature. The coolant radiators fans kick at 103 degrees of Celsius assuring the coolant temp stays below it. Without the heat-exchanger there would be no mechanism to control the oil temperature.

Bloodshot · Oct 8th, 2011, 11:34 pm

I was thinking about moving the heat exchanger up next to the engine where the charcoal canister is on stock bikes. Can anyone think of a reason this would be a bad idea?

Sputniks · Oct 8th, 2011, 11:59 pm

Quote:

Originally Posted by Bloodshot

I was thinking about moving the heat exchanger up next to the engine where the charcoal canister is on stock bikes. Can anyone think of a reason this would be a bad idea?

I wouldn't mind to replace the stock heat exchanger with a dedicated oil radiator! Just like on the image here: