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Re: Mercedes Power Unit
Posted: 22 Jan 2017, 18:14
by godlameroso
roon wrote:Not sure. I'm more familiar with it as an emissions control technology. Strange thing is that it's explicitly mentioned and permitted in the rulebook.
Wikipedia lists its two main efficiency benefits as reduced throttling losses & reduced heat rejection due to lower combustion.
Regarding throttling losses, my take is that you could potentially leave the throttle wide open, maybe even ditch it, by using fine control of EGR, boost, fuel injection, & spark to act as your replacement 'throttle.'
I'd imagine you're right, I don't really think they use throttles with these engines. Considering cars haven't had throttle cables, or IACV's for over 10 years now, it makes sense. That stuff is old school.
Re: Mercedes Power Unit
Posted: 22 Jan 2017, 18:22
by roon
Considering F1's EBD experience & cold blowing, they know how to control an engine independent of throttle plate position. Ignition & injection controls, primarily, in the V8 era. Not sure about the V6's. They could be doing some of what I mentioned & already eliminated the throttle.
If the EGR loop connects pre-compressor to post-turbine, this would aid expansion after the turbine.
Re: Mercedes Power Unit
Posted: 22 Jan 2017, 21:38
by FW17
Craziest idea ever........
Mercedes using a liquid intercooler wherein the liquid is the fuel. The fuel is the cooled with a refrigeration cycle.
Re: Mercedes Power Unit
Posted: 22 Jan 2017, 21:57
by roon
I like it. Fuel is the only phase change fluid permitted in the regs. However there is a specific provision against cooling fuel (6.5.3).
Re: Mercedes Power Unit
Posted: 22 Jan 2017, 22:03
by hurril
roon wrote:I like it. Fuel is the only phase change fluid permitted in the regs. However there is a specific provision against cooling fuel.
Well just let the fuel get hot! It'll [the fuel] be a huge buffer in the beginning of the race.
Re: Mercedes Power Unit
Posted: 22 Jan 2017, 22:43
by PlatinumZealot
That not gonna work for any extended period of time though. Fuel would be so hot after a period of time. You would lose fuel thru the vents.
Re: Mercedes Power Unit
Posted: 23 Jan 2017, 00:14
by hurril
PlatinumZealot wrote:That not gonna work for any extended period of time though. Fuel would be so hot after a period of time. You would lose fuel thru the vents.
Straight into the compressor inlet!
Re: Mercedes Power Unit
Posted: 23 Jan 2017, 00:55
by roon
hurril wrote:PlatinumZealot wrote:That not gonna work for any extended period of time though. Fuel would be so hot after a period of time. You would lose fuel thru the vents.
Straight into the compressor inlet!
Why does this sound like an excerpt from one of Bernie's backroom negotiations?
If fuel is weighed before & after the race as gruntguru suggested then burning more fuel than what is recorded by the ECU would be noticed. Unless it was an amount small enough to be obscured by the accumulated recording error of a race duration.
Re: Mercedes Power Unit
Posted: 23 Jan 2017, 01:43
by hurril
roon wrote:hurril wrote:PlatinumZealot wrote:That not gonna work for any extended period of time though. Fuel would be so hot after a period of time. You would lose fuel thru the vents.
Straight into the compressor inlet!
Why does this sound like an excerpt from one of Bernie's backroom negotiations?
If fuel is weighed before & after the race as gruntguru suggested then burning more fuel than what is recorded by the ECU would be noticed. Unless it was an amount small enough to be obscured by the accumulated recording error of a race duration.
Ha! Hadn't even thought about that.
Re: Mercedes Power Unit
Posted: 23 Jan 2017, 01:44
by wuzak
roon wrote:I like it. Fuel is the only phase change fluid permitted in the regs. However there is a specific provision against cooling fuel (6.5.3).
And using phase changing fluids for cooling is banned.
Re: Mercedes Power Unit
Posted: 23 Jan 2017, 02:07
by roon
7.6 The cooling systems of the power unit, including that of the charge air, must not intentionally make use of the latent heat of vaporisation of any fluid with the exception of fuel for the normal purpose of combustion in the engine as described in Article 5.14.
Re: Mercedes Power Unit
Posted: 23 Jan 2017, 05:38
by FW17
They are not cooling the engine but the fuel, the fuel the working fluid in the intercooler does not change state in the intercooler but in the tank. The tank is cooled to bring it back to ambient with refrigerant cycle.
Knowing how Charlie whiting works, he will not object to it till someone writes to him.
Re: Mercedes Power Unit
Posted: 23 Jan 2017, 05:48
by roon
6.5.3 The use of any device on board the car to decrease the temperature of the fuel is forbidden.
Re: Mercedes Power Unit
Posted: 23 Jan 2017, 08:55
by FW17
roon wrote:6.5.3 The use of any device on board the car to decrease the temperature of the fuel is forbidden.
That is applicable only below ambient temperature
Anyway I don't think they are doing anything like that. They are just using a large water cooled intercooler.
Previously I had written that it would be about the width of the monocoque at 600 mm, but I think it would not be any larger than 500mm to fit within the step in the floor.
Merc Intercooler size would be 300x500x150 mm
In comparison to the Ferrari intercooler of 2015 which was 300x300x125 mm
Re: Mercedes Power Unit
Posted: 23 Jan 2017, 18:31
by PlatinumZealot
From the photo the intercooler looks no taller than six inches and no deeper than six to 8 inches.
So probably 500 x 150 x 200..