Talking to a turbo expert

[Tommy Cookers]

and now even electric assisted turbo compound as in F1 2014. I'm wondering what that technology will do to hybrid road cars. I'm guessing it will be smooth and very fuel efficient.

the Wright Turbo-Compound at best efficiency (0.38 lb/bhp-hour BSFC 35% efficiency) only recovered 6% of its output from the turbines
the efficiency was largely due to running without (significant ?) throttling, enabled by the very lean mixture and 'super overdrive' aerodynamic CVT effect derived from the continuous variability of propellor pitch
ie the non-compound brothers of this engine were 33% efficient in this way
a million or so engines did the same, all with mechanically-driven centrifugal superchargers

going from 33% to 35% was not a game-changer

[350matt]

Will the new engines use EGR?

they'd be fools not to

and nothing in the rules to say you shouldn't

[Tommy Cookers]

Will the new engines use EGR?

at 10500 rpm the expected 2014 F1 engines will access the max fuel rate
as the revs rise to 12200 the cylinder pressure can fall to maintain mixture strength
or cylinder pressure can be maintained and mixture become 16% leaner
or cylinder pressure can be maintained (in part or wholly) by managed reduction in scavenging ie 'poor man's EGR'

IMO this last will be used, as the best option
it's all a matter of choice of exhaust valve timing and turbine loading by the generator (for power recovery ie compounding)
it's an inevitable consequence of increasing recovery (with only 1 turbine)

anyway, what's not to like ?

[WhiteBlue]

going from 33% to 35% was not a game-changer

I thought we expect a bit higher percentage from the 2014 F1 engines. There are some years of technology between. And you also have to consider where F1 is coming from.

[Dragonfly]

at 10500 rpm the expected 2014 F1 engines will access the max fuel rate
..............

Are we speaking about Exhaust Gas Recirculation or the abbreviation has another meaning?

[Tommy Cookers]

Exhaust Gas Recirculation

[Dragonfly]

Ah, thanks. Now I am going to carefully read and try to comprehend what you wrote. I'm not into engines and have some thin knowledge about EGR in road cars but would like to broaden my horizon a bit.

[Tommy Cookers]

the Ford Ecoboost data plots that pgfpro kindly posted show (3/3) that the downsized downspeeded Ecoboost engine is a dead dog below 60 kph, compared to an equal NA engine
there is a reference to gradeability and towing as performance considerations
(the PR dept censor missed those ?)

governments demand numbers, the car industry complies, in the real world the benefits fall far short of the numbers
everyone finds their 65 mpg cars (SI) are really 45 mpg and not much better in consumption than before
the 2014 rules are another face of the same process, the FIA has declared its goal (starting by demonizing the incumbent NA)

BTW this seems a good time to say that I have never disputed the efficiency of the turbocharged SI engine

@Dragonfly
this would be internal EGR, which is rather different in purpose to the much older and better known (external) EGR

[olefud]

Will the new engines use EGR?

at 10500 rpm the expected 2014 F1 engines will access the max fuel rate
as the revs rise to 12200 the cylinder pressure can fall to maintain mixture strength
or cylinder pressure can be maintained and mixture become 16% leaner
or cylinder pressure can be maintained (in part or wholly) by managed reduction in scavenging ie 'poor man's EGR'

IMO this last will be used, as the best option
it's all a matter of choice of exhaust valve timing and turbine loading by the generator (for power recovery ie compounding)
it's an inevitable consequence of increasing recovery (with only 1 turbine)

anyway, what's not to like ?

I need a bit more explanation. I understand EGR to lower combustion temps and avoid NOx. But it would seem that once the max fuel flow is reached there is little to gain in going to higher RPM and/or adding inert exhaust gas “filler”. Higher RPM would add friction but no additional energy with limited fuel flow.

When NASCAR first went to restrictor plate racing, engines were run at the old 8xxx RPM range with hyper CR. But then the RPM came down into the 6xxx range, though with probably pressure wave tuning and other refinements the RPM has crept back up a bit.

[WhiteBlue]

the Ford Ecoboost data plots that pgfpro kindly posted show (3/3) that the downsized downspeeded Ecoboost engine is a dead dog below 60 kph, compared to an equal NA engine
there is a reference to gradeability and towing as performance considerations
(the PR dept censor missed those ?)..

Dead dog is a bit over the top. This traction is only relevant for people who want to tow a 2ton trailer behind their tiny Fiesta. They should probably buy another car anyway.

[pgfpro]

the Ford Ecoboost data plots that pgfpro kindly posted show (3/3) that the downsized downspeeded Ecoboost engine is a dead dog below 60 kph, compared to an equal NA engine
there is a reference to gradeability and towing as performance considerations
(the PR dept censor missed those ?)..

Dead dog is a bit over the top. This traction is only relevant for people who want to tow a 2ton trailer behind their tiny Fiesta. They should probably buy another car anyway.

I have a friend that bought a new Ecoboost F150 and this thing is amazing. It pulls like a big block even below 60kph and gets great fuel mileage. A very fun truck to drive. the hard part is keeping your foot out of the gas.

[Tommy Cookers]

at 10500 rpm the expected 2014 F1 engines will access the max fuel rate
as the revs rise to 12200 the cylinder pressure can fall to maintain mixture strength
or cylinder pressure can be maintained and mixture become 16% leaner
or cylinder pressure can be maintained (in part or wholly) by managed reduction in scavenging ie 'poor man's EGR'

IMO this last will be used, as the best option
it's all a matter of choice of exhaust valve timing and turbine loading by the generator (for power recovery ie compounding)
it's an inevitable consequence of increasing recovery (with only 1 turbine)

I need a bit more explanation. I understand EGR to lower combustion temps and avoid NOx. But it would seem that once the max fuel flow is reached there is little to gain in going to higher RPM and/or adding inert exhaust gas “filler”. Higher RPM would add friction but no additional energy with limited fuel flow.
When NASCAR first went to restrictor plate racing, engines were run at the old 8xxx RPM range with hyper CR.

since CVT is not allowed (for 2014 F1, assuming that is sufficiently 'on thread')
avoiding rpm higher than 10500 means mostly running between 9000 and 10500 rpm
IMO this is worse, throwing away much free fuel and some recoverable power without worthwhile benefits

maximum useful PV cycle excursion in-cylinder throughout the rpm range is crucial IMO
higher in the rpm range, packing the cylinders by including some EG is better than the other two strategies (is my guess)
because it will better maintain temperature/pressure at the top of the cycle as rpm rises and outstrips the fuel supply
and it minimises losses in blowdown, by having less difference at blowdown between cylinder pressure and exhaust pressure

the rules are the way they are for good reasons (is my guess)
ie future sweating out of ever more recovered power will take us into ever higher exhaust pressures anyway (is my guess)

alternatively (and conventionally), retard ignition around 10500 to allow higher CR matched to 11200-12200 running with normal ignition timing and cylinders charged for stoichiometric mixture (or more heavily charged for lean mixture)
combustion chamber temps will constantly change, so ign retard/knock sensor must be available with any engine strategy


the transmission can at most circuits be used as a 'poor man's CVT' to alleviate the above engine difficulty
(I believe 2014 will have the same 8 gears and the same final drive ratio for all/nearly all circuits)
typically eg (having accelerated through the gears) the driver could hold at max speed 7th 12200 rpm or 8th 10500 rpm
so the engine need only be optimised re CR/'boost' match for an 8% rpm range, eg 10500-11300 or 11300-12200
(this would be helped if the final drive ratio could be varied with the circuit)

all this assumes that we are not allowed modulated displacement (loosely, 5 cylinder running that would work very well here)

[olefud]

at 10500 rpm the expected 2014 F1 engines will access the max fuel rate
as the revs rise to 12200 the cylinder pressure can fall to maintain mixture strength
or cylinder pressure can be maintained and mixture become 16% leaner
or cylinder pressure can be maintained (in part or wholly) by managed reduction in scavenging ie 'poor man's EGR'

IMO this last will be used, as the best option
it's all a matter of choice of exhaust valve timing and turbine loading by the generator (for power recovery ie compounding)
it's an inevitable consequence of increasing recovery (with only 1 turbine)

I need a bit more explanation. I understand EGR to lower combustion temps and avoid NOx. But it would seem that once the max fuel flow is reached there is little to gain in going to higher RPM and/or adding inert exhaust gas “filler”. Higher RPM would add friction but no additional energy with limited fuel flow.
When NASCAR first went to restrictor plate racing, engines were run at the old 8xxx RPM range with hyper CR.

since CVT is not allowed (for 2014 F1, assuming that is sufficiently 'on thread')
avoiding rpm higher than 10500 means mostly running between 9000 and 10500 rpm
IMO this is worse, throwing away much free fuel and some recoverable power without worthwhile benefits

maximum useful PV cycle excursion in-cylinder throughout the rpm range is crucial IMO
higher in the rpm range, packing the cylinders by including some EG is better than the other two strategies (is my guess)
because it will better maintain temperature/pressure at the top of the cycle as rpm rises and outstrips the fuel supply
and it minimises losses in blowdown, by having less difference at blowdown between cylinder pressure and exhaust pressure

the rules are the way they are for good reasons (is my guess)
ie future sweating out of ever more recovered power will take us into ever higher exhaust pressures anyway (is my guess)

alternatively (and conventionally), retard ignition around 10500 to allow higher CR matched to 11200-12200 running with normal ignition timing and cylinders charged for stoichiometric mixture (or more heavily charged for lean mixture)
combustion chamber temps will constantly change, so ign retard/knock sensor must be available with any engine strategy


the transmission can at most circuits be used as a 'poor man's CVT' to alleviate the above engine difficulty
(I believe 2014 will have the same 8 gears and the same final drive ratio for all/nearly all circuits)
typically eg (having accelerated through the gears) the driver could hold at max speed 7th 12200 rpm or 8th 10500 rpm
so the engine need only be optimised re CR/'boost' match for an 8% rpm range, eg 10500-11300 or 11300-12200
(this would be helped if the final drive ratio could be varied with the circuit)

all this assumes that we are not allowed modulated displacement (loosely, 5 cylinder running that would work very well here)

I think I get your point. My take is that EGR is a bit illusory since, while increasing pressure, it dilutes the fuel/air mixture and decreases combustion temperature. Also, since the fuel flow limit means the Δ fuel is zero once the limit is reached, i.e. the HP curve falls off a cliff. Some revs beyond the HP max are useful, but IMO, a prompt shift would be necessary.

If higher revs are absolutely needed, I would first look at a higher CR with limited boost at lower revs and a clean fuel mixture. But I suspect that just taking what the engine allows with modest over the top of the HP curve and shifting when the HP falls to the HP a shift yields would be best. Of course I’m just speculating.

[Tommy Cookers]

now thinking .......
the rpm range in the highest gears currently is around 11% (increasing to about 20% in the lower gears)
so my 16% was pessimistic for the longest and most important phase, the high gear running
now I agree that under substantial acceleration they should typically use 9800 - 11300
at high speed they should always try to use 10500 or more (conceptually the power should be constant with any rpm over 10500)
actually it will fall slightly, depending on how the engine operates
but the better the power holds up over 10500 the better the available axle torque and performance from choosing to hold a gear or up-change, this will be important at places where the available high ratios are less than ideal
(once established, there will be only the same 8 ratios permitted for the whole season)

[Powerslide]

compression stroke pumping loss, what about the physic of a large piston's higher surface area but without boost compared to a boost but small piston? a chamber with atmospheric pressure but being compressed by a large piston compared to a smaller piston say with enough boost to equate to the same amount of air. would there be a reduction in pumping loss?

its like those rubber bag air spring where if lowered it flattens itself and become wider or increase in bore, it results in higher torque or harder suspension. (is there a term for this)