Don Terrill’s Speed-Talk

ptuomov wrote:I personally think that they are more likely to burn the oil in the exhaust port and manifold than in the combustion chamber. Oil in the combustion chamber is a bit difficult to control as it cause preignition. In the exhaust manifold, it can be used to run the turbo, which has the electric recovery system attached to it.

Ah ! Turbo,, This shows how close i follow F1, i had totally forgotten thet went back to turbo engines and my post re octane was relevent to info i had read on the N/A F1 engines. I get the donkey of the day award!
That video link posted by tjus explaining the system they use is quite interesting.

The oil/fuel mix injector is an interesting and relatively exotic piece as opposed to a pump fed set of oil squirters. Im interested as to where the mixture takes place.

Reminds me of a two stroke.

They "only" rev to 12500rpm as opposed to the 20000rpm of the normally aspirated V8's of just a few years ago...

they achieved a remarkable 50-percent thermal efficiency figure from the 1.6-liter 90-degeree V6 turbo-hybrid screamer, marking the first time any of their competition engines have made more useful power than waste energy.

Very bad writing.

Wondering what the efficiency is without all the hybrid add ons?

On another note the heat recovery device (MGU-H as they call it) is attached to the turbo and within the V of the engine. Its supposed to by the most expensive and difficult to develop part of the whole system. One of the reasons why Honda has been having such a hard time this season....

the oil they use is no more related to oil you would be used to or even have seen a spec on , ill see can i find an articular i used for classes where the oil companies fought back to the city electric car and hired a few old f1 designers and a collage , any way engine was super efficient high rpm 2 ring piston , carbon chassis , when they requested an oil for the engine the oil companies had to make one to suit , and even after supplying it they had no grade on it as it didn't fit in the conventional specs charts , don't forget the fuel they used the last time they had turbos for the 1500bhp 1.5 lit was i think near 70 stg a lit back then , not even closely related to petrol

cjperformance wrote:

ptuomov wrote:I personally think that they are more likely to burn the oil in the exhaust port and manifold than in the combustion chamber. Oil in the combustion chamber is a bit difficult to control as it cause preignition. In the exhaust manifold, it can be used to run the turbo, which has the electric recovery system attached to it.

Ah ! Turbo,, This shows how close i follow F1, i had totally forgotten thet went back to turbo engines and my post re octane was relevent to info i had read on the N/A F1 engines. I get the donkey of the day award!
That video link posted by tjus explaining the system they use is quite interesting.

Just because it's turbo doesn't mean things don't get "weird" at higher RPM.

It's my understanding that the F1 engines revving to 20000 was not a mechanical limitation, but a fuel limitation. If the "gasoline" could burn faster, they'd go higher. Even at "only" 10-12,5k with a turbo, flame speed is really important.

Detonation kills engines at low RPM, not so much at high RPM if it ever happens in the first place.

From what I remember they did hit 22000rpm for a while , they idle was 5000rpm ,

tjus wrote: ↑Mon Sep 18, 2017 5:39 pm funny how they had to limit oil consumption in f1 engines....

They have a maximum fuel flow rate combined with a maximum fuel quantity. If you could add 1% oil you could get 1% more fuel flow in the form of oil and slightly more than 1% more power. The problem of the lower octane of oil appears not to be a problem, perhaps due to the ability of direct injection, with trick injection timing, multiple squirts, etc, to suppress detonation; also the possibility you can use the oil during "energy harvesting" when the peak cylinder pressure is lower(?).
Ferrari actually used some kind of special oil separate from engine oil, but that suggests that the engine oil also could be some kind of high octane oil.
I was wondering how they inject the oil without having an obvious special injection system if they aren't just mixing it with the gas where it should show up in the after-race fuel analysis.

They no longer do this (in a way the FIA can detect).

Anyway, ...if ya ain't cheatin, ya ain't tryin...

gunt wrote: ↑Sat Oct 07, 2017 4:56 pm From what I remember they did hit 22000rpm for a while , they idle was 5000rpm ,

Yes, 22,000 was the highest IIRC. The FIA imposed an 18,000 rpm limit for a while, then for this V6 formula I think it's 15,000 rpm. The teams ended up using less than 11,500 rpm due to the premium on efficiency.

peejay wrote: ↑Mon Sep 18, 2017 8:30 pm I don't think it is necessarily "burns slower" as much as it is that they had/have been running the engines on controlled detonation, since they were finding the burn speed limitations of gasoline-ish fuels. If you can't get it to burn fast enough, make it detonate!

But, these engines run slower than 2/3 the rpms they were using before. I don't think they would need to speed up the burn.

peejay wrote: ↑Wed Sep 20, 2017 8:49 pm
It's my understanding that the F1 engines revving to 20000 was not a mechanical limitation, but a fuel limitation. If the "gasoline" could burn faster, they'd go higher. Even at "only" 10-12,5k with a turbo, flame speed is really important.

No, it was absolutely a mechanical limitation. They did have problems with the burn, but that was the result of the ultra short strokes due to mechanical limits with the consequent large piston diameters. The chamber ended up in the volume of the valve reliefs. It limited their CR. Honda was at one time using 13.5:1 instead of the 15.5:1 they wanted. Honda went to fused hollow rods to lower the amount of twist so they could reduce the valve/valve relief clearance and gain some CR.

Also, the short stroke, big piston area changed the balance of stress (tension vs compression) on the rods to favor I-beams which are ultimately much stronger overall than H-beams (H-beams have a slight advantage in tensile strength to weight whereas I-beams are much stronger in compression). They gave up on H-beams after about 1997 (about 16,500 rpm) after using them almost exclusively since about the late 1970s.

ptuomov wrote: ↑Mon Sep 18, 2017 9:40 pm I personally think that they are more likely to burn the oil in the exhaust port and manifold than in the combustion chamber. Oil in the combustion chamber is a bit difficult to control as it cause preignition. In the exhaust manifold, it can be used to run the turbo, which has the electric recovery system attached to it.

At first I thought this was not an effective idea as the engine has to run lean to burn oil in the exhaust, but if it is done during "harvesting" it would be ok to run the engine lean, so this then solves the octane/detonation and oil/fuel mixture problems. It will put a little more energy into the batteries. Good idea!

MikeD wrote: ↑Mon Sep 18, 2017 12:48 pm http://www.enginelabs.com/news/video-me ... fficiency/

Ah-Ha. The commentators during F1 racing had said more than once they were getting 50% efficiency. I was astounded. But, this is on a test bench. It would be very interesting to see what cycle they are using. How much shaft power is coming out of the engine vs what is coming off the turbine through its generator? If you don't already know, gas turbine-engined generators get almost 60% efficiency. The turbine is MUCH more efficient as a motor than is a reciprocating engine.

The F1 systems can have a decoupled compressor. The turbine is not directly running the compressor so is not necessarily supercharging the engine. Now the engine is inherently only about 30% efficient at maximum, but the turbine is MUCH better. If the turbine runs a generator instead of a compressor you can get something approaching 60%.
My guess is that the engine is basically feeding the turbine and a very high share of the total power output is coming off the the turbine's generator with little turbine power going to the compressor and the engine is running at low boost, if any boost, and moderate or low engine power output. So, the 50% efficiency cycle should be a moderate or low cruse cycle with engine running rather slow.
Just a guess.