how much turbo pressure does today's f1 engines have?

[J.A.W.]

See pressure charts here: http://www.flightglobal.com/pdfarchive/ ... 01223.html

The aforementioned Napier Nomad was operating on a "...nominal comp-ratio of 49/1".
(On a 2T static/geometric ratio of 8:1)

[Tommy Cookers]

the Nomad showed that CI with CR as low as a compounded SI engine's could use cheap fuel - but it was not more efficient
ie the Nomad 1 had the same 'best bte' as the Wright Turbo Compound (and the Nomad 2's was worse ?)
but diesel fuel seems to be not intrinsically cheap

normal piston engines are anyway compounded in flight at reasonable altitude and speed by inherent exhaust jet effect
Napier (and Wright) clearly claim merit only in relatively slow flight
the only significant CI (mechanically) compounded engine was/is a USSR 42 and 56 cylinder marine job - eg 5200 hp/unit

yes these to a greater or lesser extent benefit from heat dilution as does F1
the Nomad of course had multi-stage compressors and axial turbines - F1 limits itself to single stage

btw
airliners operate in cruise with their altimeters set to 1013 millibar regardless of actual surface or sea level pressure
so eg Flight Level 360 means fictitious 36000' reading not 36000' actual
and the plane coming the other way will be flying at a similarly fictitious 37000' reading - so is seperated by an actual 1000'

[strad]

wuzak ;
Is this the same as the MAP sensor on some cars?
If so maybe you can help me understand why some American cars run a MAF sensor and some run a MAP sensor.
And if you can why some people say one is better to run than the other.

[J.A.W.]

the Nomad showed that CI with CR as low as a compounded SI engine's could use cheap fuel - but it was not more efficient
ie the Nomad 1 had the same 'best bte' as the Wright Turbo Compound (and the Nomad 2's was worse ?)
but diesel fuel seems to be not intrinsically cheap

normal piston engines are anyway compounded in flight at reasonable altitude and speed by inherent exhaust jet effect
Napier (and Wright) clearly claim merit only in relatively slow flight
the only significant CI (mechanically) compounded engine was/is a USSR 42 and 56 cylinder marine job - eg 5200 hp/unit

yes these to a greater or lesser extent benefit from heat dilution as does F1
the Nomad of course had multi-stage compressors and axial turbines - F1 limits itself to single stage

btw
airliners operate in cruise with their altimeters set to 1013 millibar regardless of actual surface or sea level pressure
so eg Flight Level 360 means fictitious 36000' reading not 36000' actual
and the plane coming the other way will be flying at a similarly fictitious 37000' reading - so is seperated by an actual 1000'

Actually T-C, if you take the trouble to read the 'Flight' article..
- it is pointed out that the Wright 'blow-down' type of turbo-compound was fully efficient only over a narrow
operating band (while running on expensive hi-test avgas - 115/145 - & yet still hard on the limits of meltdown)..

By contrast, the Napier was more fuel efficient, & over the full range of engine operations (power settings
and altitude bands) while safe against detonation - on any available aviation fuel..

The Napier Deltic is a turbo-compound engine, others inc' Detroit Diesel & Volvo - are still in production.

[McMrocks]

100kg/h= 0.0027kg/s of fuel
Ratio of Air to fuel is 14.7
0.0027*14.7 = 0.408 kg/s of air is needed

And that mass needs to fit in following Volume: 12000rpm ASSUMPTION!
V=0.5*V*n = 0.5*1,6l/1000*12000/60= 0.16 m³/s

density is 0.408kg/0.16m³= 2,55kg/m³
density = 2.55 kg/m³
R = 287.2 KJ/(KgK)
T= 50°C = 323.15°K ASSUMPTION!!!!
p= density * R* T

p= 2.55*287.2*323.15= 236662.134 N/m²
=2.36662 bar

That is the pressure at the inlet valve. The assumption is that the air has 50°C after the intercooler. Furthermore that calculation is made at 12000rpm as u can see above.

To know the pressure after the TC you need to know the drop in pressure in the intercooler as well as the actual temperature at the air inlet valve.

Good night. It's not accurate at all. The engines can handle the 100kg/h at rpms under 12.000. Which means the same mass of air needs to be pressed into a even tinier volume. Just change the numbers if you know the miniumum rpm that a F1 engine needs to burn 100kg/h.

I am drunk. So i'll stop here

[roon]

The engines can handle the 100kg/h at rpms under 12.000. Which means the same mass of air needs to be pressed into a even tinier volume. Just change the numbers if you know the miniumum rpm that a F1 engine needs to burn 100kg/h.

I suppose if you tried maximum fuel flow at too low an engine speed, you would end up with this:

https://www.youtube.com/watch?v=kqVwHJPV-XE
See dyno runs at 3:00.

It would be interesting to know what RPM range these engines would run at if they dropped the 10.5k RPM threshold for the maximum fuel flow rate. Minimum engine speeds would be limited by cylinder pressures, but advantaged by reduced piston speed & acceleration. Would development trend toward heavier, slower running components with high cylinder pressures? Or toward lighter, faster running components with lower cylinder pressures?

[wuzak]

wuzak ;
Is this the same as the MAP sensor on some cars?

Yes

If so maybe you can help me understand why some American cars run a MAF sensor and some run a MAP sensor.
And if you can why some people say one is better to run than the other.

Mass air flow is what you are trying to read to calculate the amount of fuel required for combustion.

I think, therefore, the MAF would be more accurate, but I am not sure. Wiki suggests MAF is very accurate when used in conjunction with an oxygen sensor in the exhaust.

https://en.wikipedia.org/wiki/Mass_flow_sensor
https://en.wikipedia.org/wiki/MAP_sensor

[strad]

Ok Thanks
My 04 Cobra has a 90mm MAF.
On some sites there is discussion about the MAP vs MAF and they had me confused. Not too hard to do.

[wuzak]

Ok Thanks
My 04 Cobra has a 90mm MAF.
On some sites there is discussion about the MAP vs MAF and they had me confused. Not too hard to do.

Probably has the oxygen sensor too.

[Tommy Cookers]

[quote=J.A.W.]The Napier Deltic is a turbo-compound engine, others inc' Detroit Diesel & Volvo - are still in production.[/quote]

Napier never claimed the Deltic was compounded ie recovered significant power from the turbine
like a typical diesel it had a high CR (variously 15.5 - 19.2:1)and didn't preserve its exhaust pulses
the rail Deltic 18-25 had 4.2 psi 'boost' - not enough to actually give the engine a supercharge
(btw the generator was 89% efficient and the traction motors maybe 85% and the train heating was electrical etc etc)
the naval Deltic 18-25 had best bsfc of 0.382 lb

Napier stated the later T models had 'geared-in' turbochargers
the main naval 2500 hp Deltic had 7.9 psi boost - the last 3700 hp Deltics for Indian navy used 19 psi
the similarly-purposed USSR Zvedza M504 etc has 'only' 13:1 CR and recovers only at high power - best bsfc c. 0.37 lb

so you'll find Detroit Diesel and Volvo recover similarly token amounts

of the engines that were called compounds by their makers .....

Napier's E185 Compound Deltic (prototyped-only) had a 12 stage compressor/3 stage turbine unconnected to the crank
(aimed at 6000 hp though failing at 5600 hp as the rod design predicted) it presumably like the Nomad had a low CR
only the Nomad II (also having many staged turbo) claimed really outstanding efficiency - 0.32 lb/ehp
but Nomad I (0.35 lb) and II claimed sfc wrt effective horsepower ie they counted exhaust thrust (which Wright didn't)
Nomads were test flown (Napier at Luton) on a Lincoln (with its Merlins presumably)

btw
Napier closed Acton in 1968
Napier Liverpool supplied new 500 hp Sea Lions till 1956

[J.A.W.]

Actually T-C, Rolls-Royce preremptorily closed Napier as an aircraft engine concern in 1962,
& subsequently the Acton works - sans concern for the extant cadre of highly experienced designers, engineers & craftsmen - as such, it was a cause of 'questions in Parliament' - in 1963..

The Napier name today is still attached to big turbo-tech, & somewhat ironically, Detroit Diesel 2T mills
(still widely used for NATO Mil Spec purposes) are built/supported/owned by R-R.

[gruntguru]

wuzak ;
Is this the same as the MAP sensor on some cars?

Yes

If so maybe you can help me understand why some American cars run a MAF sensor and some run a MAP sensor.
And if you can why some people say one is better to run than the other.

Mass air flow is what you are trying to read to calculate the amount of fuel required for combustion.

I think, therefore, the MAF would be more accurate, but I am not sure.

A "hot wire" MAF directly measures air mass flow - exactly what you need to know when you want to flow fuel into the engine at a chosen AFR.
A MAP sensor measures the pressure in the intake plenum. To calculate mass flow, the system must also measure air temperature in the plenum, and engine speed. The system then assumes the VE of the engine at various RPM to calculate mass flow. There are many conditions where the assumed VE can be wrong - engine wear, carbon buildup, blocked exhaust etc etc. This is the main source of "inaccuracy" when compared to the MAF sensor.