Honda Power Unit Hardware & Software

[gruntguru]

By the way on the other topic, what lambda ratio do you suppose the Mercedes engines use?

Huge guess here. Somewhere between 1.5 and 1.8

What intake air pressure (abs) and temperature do you estimate Lambda 1.5/1.8 equates to (pre-charge cooler)?

That depends on CAT (charge air temperature). Assuming 14.7:1 stoich for the fuel gives air flow of 0.6125 kg/s for lambda 1.5 and 0.735 for 1.8. This is trapped mass ie the air that stays in the chamber for combustion. If there is any scavenging, that will require additional air flow. Dealing with the trapped mass only for now:

Volume flow = displacement/2 x revolutions per second x VE(trapped) = (1.6 E-3)/2 x 11,000/60 x 1.1 = 0.1613 m3/s.

So for lambda 1.5 (air flow 0.6125 kg/s) the air density in the plenum needs to be 0.6125/0.1613 = 3.8 kg/m3 (DR = 3.8/1.2 = 3.17)
For lambda 1.8 the air density required is 0.735/0.1613 = 4.56 kg/m3. (DR = 4.56/1.2 = 3.8) (DR is Density Ratio - the ratio of charge density to ambient air density)

If the charge air is intercooled back to ambient temperature (not feasible but a useful benchmark) DR = PR so Lambda 1.5 and 1.8 require a PR of 3.17 and 3.8 respectively. Using ideal gas law => P1xV1/T1=P2xV2/T2 so P2/P1=V1/V2 x T2/T1 or
PR = DR x TR (V1/V2 = Density2/Density1 = DR)

So - pick your favourite CAT and plug into the formula.
For example
T1 (ambient) = 293K and T2 (CAT) = 313K and lambda 1.5 gives
PR=DRxTR= 3.17 x 313K/293K = 3.38

A more extreme example.
T1 (ambient) = 293K and T2 (CAT) = 343K and lambda 1.8 gives
PR=DRxTR= 3.8 x 343K/293K = 4.45 (which is approximately 4.45 bar absolute MAP.)

[Abarth]

Is the 46 MJKg value a close estimation to reality?

Hard to say. I always assumed it's rather high, and seemingly Mercedes gave a value of 44.72MJ/kg,
which makes all these power (=efficiency) numbers even more incredible...

http://www.f1technical.net/forum/viewto ... 35#p617058

[godlameroso]

Funny, apparently we're pretty much in the ballpark. The Honda runs just under 4 bar absolute in the race. Wouldn't be surprised then for Mercedes to be running ~4.5 bar abs like GG's upper limit suggests.

[PlatinumZealot]

Huge guess here. Somewhere between 1.5 and 1.8

What intake air pressure (abs) and temperature do you estimate Lambda 1.5/1.8 equates to (pre-charge cooler)?

That depends on CAT (charge air temperature). Assuming 14.7:1 stoich for the fuel gives air flow of 0.6125 kg/s for lambda 1.5 and 0.735 for 1.8. This is trapped mass ie the air that stays in the chamber for combustion. If there is any scavenging, that will require additional air flow. Dealing with the trapped mass only for now:

Volume flow = displacement/2 x revolutions per second x VE(trapped) = (1.6 E-3)/2 x 11,000/60 x 1.1 = 0.1613 m3/s.

So for lambda 1.5 (air flow 0.6125 kg/s) the air density in the plenum needs to be 0.6125/0.1613 = 3.8 kg/m3 (DR = 3.8/1.2 = 3.17)
For lambda 1.8 the air density required is 0.735/0.1613 = 4.56 kg/m3. (DR = 4.56/1.2 = 3.8) (DR is Density Ratio - the ratio of charge density to ambient air density)

If the charge air is intercooled back to ambient temperature (not feasible but a useful benchmark) DR = PR so Lambda 1.5 and 1.8 require a PR of 3.17 and 3.8 respectively. Using ideal gas law => P1xV1/T1=P2xV2/T2 so P2/P1=V1/V2 x T2/T1 or
PR = DR x TR (V1/V2 = Density2/Density1 = DR)

So - pick your favourite CAT and plug into the formula.
For example
T1 (ambient) = 293K and T2 (CAT) = 313K and lambda 1.5 gives
PR=DRxTR= 3.17 x 313K/293K = 3.38

A more extreme example.
T1 (ambient) = 293K and T2 (CAT) = 343K and lambda 1.8 gives
PR=DRxTR= 3.8 x 343K/293K = 4.45 (which is approximately 4.45 bar absolute MAP.)

I see, you worked it from the "system side." My God I'm rusty! used to do this back in Uni -I should be ashamed lol. Should have done this first before i looked at the turbo maps.
It looks my T88 compressor example was not the right fit. (where the pressure ratio is a low 2.2 for the given air flow).. it would better for a much bigger engine. Nonetheless it is good clue of the sizing of these F1 compressors. They seem to operate at a very high speed to got those sorts of high pressure ratios to ram the air into a tiny 1.6liter V6.

[Brian Coat]

Huge guess here. Somewhere between 1.5 and 1.8

What intake air pressure (abs) and temperature do you estimate Lambda 1.5/1.8 equates to (pre-charge cooler)?

That depends on CAT (charge air temperature). Assuming 14.7:1 stoich for the fuel gives air flow of 0.6125 kg/s for lambda 1.5 and 0.735 for 1.8. This is trapped mass ie the air that stays in the chamber for combustion. If there is any scavenging, that will require additional air flow. Dealing with the trapped mass only for now:

Volume flow = displacement/2 x revolutions per second x VE(trapped) = (1.6 E-3)/2 x 11,000/60 x 1.1 = 0.1613 m3/s.

So for lambda 1.5 (air flow 0.6125 kg/s) the air density in the plenum needs to be 0.6125/0.1613 = 3.8 kg/m3 (DR = 3.8/1.2 = 3.17)
For lambda 1.8 the air density required is 0.735/0.1613 = 4.56 kg/m3. (DR = 4.56/1.2 = 3.8) (DR is Density Ratio - the ratio of charge density to ambient air density)

If the charge air is intercooled back to ambient temperature (not feasible but a useful benchmark) DR = PR so Lambda 1.5 and 1.8 require a PR of 3.17 and 3.8 respectively. Using ideal gas law => P1xV1/T1=P2xV2/T2 so P2/P1=V1/V2 x T2/T1 or
PR = DR x TR (V1/V2 = Density2/Density1 = DR)

So - pick your favourite CAT and plug into the formula.
For example
T1 (ambient) = 293K and T2 (CAT) = 313K and lambda 1.5 gives
PR=DRxTR= 3.17 x 313K/293K = 3.38

A more extreme example.
T1 (ambient) = 293K and T2 (CAT) = 343K and lambda 1.8 gives
PR=DRxTR= 3.8 x 343K/293K = 4.45 (which is approximately 4.45 bar absolute MAP.)

Thanks, GG. Lets assume your second example.

A couple of things strike me.

For the ~4.5 Bar case, the compressor exit must be 500K+ even if the compressor is very efficient. So that's a heck of a lot of enthalpy being chucked out of the sidepod during intercooling, even if it's "only" taken down to 343K. Lost energy.

Also, if we believe the 20:1 CR rule for next year is anywhere near a "constraint on current practice" then starting from 343K/4.45Bar, the pressure and temperature approaching TDC would be very high indeed, which makes for interesting combustion system speculation re: Mercedes Benz.

Make sense or not?

[godlameroso]

Makes you wonder if there's any benefit to recover heat energy from the compressor side, makes you wonder about Ferrari's water to air and air to air charge cooler setup. And how much heat is actually coming from that compressor.

[PlatinumZealot]

Waste heat can be used to heat fuel... Say the same water lines from the inter-cooler you pass into the fuel heater. Might be redundant.. but hey..

Another interesting option is a closed loop rankine cycle. Generate steam to make electrical energy. You will still need a condenser and another heat exchanger to cool the water enough so that it can be used to cool the charge air again though.

[godlameroso]

Waste heat can be used to heat fuel... Say the same water lines from the inter-cooler you pass into the fuel heater. Might be redundant.. but hey..

Another interesting option is a closed loop rankine cycle. Generate steam to make electrical energy. You will still need a condenser and another heat exchanger to cool the water enough so that it can be used to cool the charge air again though.

Interesting, could be, there's no rule that says you can only harvest electricity from the turbine. Only that you use a mgu-h to do it. You could use a thermoelectric generator incorporated into the MGU-H which could absorb heat convert it to electricity and generate a cooling effect somewhere else, like in the charge cooling.

https://en.wikipedia.org/wiki/Thermoelectric_cooling

current technology is limited, but every bit helps, and who knows what this tech could be developed into.

Even BMW took a stab at it so I'm guessing this tech is floating around the car world waiting for someone to tap it

http://energy.gov/sites/prod/files/2014 ... /mazar.pdf

[gruntguru]

What intake air pressure (abs) and temperature do you estimate Lambda 1.5/1.8 equates to (pre-charge cooler)?

That depends on CAT (charge air temperature). Assuming 14.7:1 stoich for the fuel gives air flow of 0.6125 kg/s for lambda 1.5 and 0.735 for 1.8. This is trapped mass ie the air that stays in the chamber for combustion. If there is any scavenging, that will require additional air flow. Dealing with the trapped mass only for now:

Volume flow = displacement/2 x revolutions per second x VE(trapped) = (1.6 E-3)/2 x 11,000/60 x 1.1 = 0.1613 m3/s.

So for lambda 1.5 (air flow 0.6125 kg/s) the air density in the plenum needs to be 0.6125/0.1613 = 3.8 kg/m3 (DR = 3.8/1.2 = 3.17)
For lambda 1.8 the air density required is 0.735/0.1613 = 4.56 kg/m3. (DR = 4.56/1.2 = 3.8) (DR is Density Ratio - the ratio of charge density to ambient air density)

If the charge air is intercooled back to ambient temperature (not feasible but a useful benchmark) DR = PR so Lambda 1.5 and 1.8 require a PR of 3.17 and 3.8 respectively. Using ideal gas law => P1xV1/T1=P2xV2/T2 so P2/P1=V1/V2 x T2/T1 or
PR = DR x TR (V1/V2 = Density2/Density1 = DR)

So - pick your favourite CAT and plug into the formula.
For example
T1 (ambient) = 293K and T2 (CAT) = 313K and lambda 1.5 gives
PR=DRxTR= 3.17 x 313K/293K = 3.38

A more extreme example.
T1 (ambient) = 293K and T2 (CAT) = 343K and lambda 1.8 gives
PR=DRxTR= 3.8 x 343K/293K = 4.45 (which is approximately 4.45 bar absolute MAP.)

Thanks, GG. Lets assume your second example.

A couple of things strike me.

For the ~4.5 Bar case, the compressor exit must be 500K+ even if the compressor is very efficient. So that's a heck of a lot of enthalpy being chucked out of the sidepod during intercooling, even if it's "only" taken down to 343K. Lost energy.

Also, if we believe the 20:1 CR rule for next year is anywhere near a "constraint on current practice" then starting from 343K/4.45Bar, the pressure and temperature approaching TDC would be very high indeed, which makes for interesting combustion system speculation re: Mercedes Benz.

Make sense or not?

Assuming Isentropic compression and ideal gas (a bit rubbery for such high pressures and temps), 20:1 CR will increase pressure by a factor of 66 so 4.45 bar @ BDC becomes 293.7 bar @TDC (plus pressure rise due to combustion).

Similarly temperature increases by a factor of 3.3 so 343K becomes 1132K (859*C) at TDC.

[loner]

so 2 tokens 1 for lighter block another for the exhaust
so what was that quote in the mobil1 website then

Honda have earmarked development tokens to be spent in Malaysia to allow a big upgrade to the engine. With the turbo, MGU and inlet system all now optimal, it’s expected that a lean burn technology will be the result of this development.

[PhillipM]

Well, you knew that was speculation/rubbish because Honda themselves said they wouldn't introduce the new combustion concept this year.

[GoranF1]

The new power unit has a lighter engine block for better reliability and a redesigned exhaust to boost efficiency

http://m.bbc.com/sport/formula1/37503760

[diffuser]

Well, you knew that was speculation/rubbish because Honda themselves said they wouldn't introduce the new combustion concept this year.

I saw somewhere that it would require too much work to remap/retune the PU for the new combustion concept.

I guess he'd rather have them working on next years PU.

[godlameroso]

I wonder how making the block, or crank case lighter would improve reliability. Maybe it means the thinner but equally strong block has less heat sink effect? As for the exhaust I'm curious as well, I wonder if they tried to design a scavenge pipe like Ferrari used in its v8.

[PlatinumZealot]

A little in accurate news from Mobil1, but at least we know Honda does intend to introduce Jet-ignition sometime in the future.

http://www.mobil1thegrid.com/article/st ... ress-2016/

Nevertheless, there have been races this season where the McLaren-Honda still appears to lack far more than a few tenths of horsepower. This is where Honda are about to catch up. In a race, the Honda engine currently uses too much fuel relative to its rivals, who have applied highly advanced lean burn combustion solutions, which allows the limited fuel to produce maximum horsepower throughout the race.

With a conventional combustion set up, the Honda cannot match this from good engineering alone, so a step change is required in the combustion design. For Ferrari and Mercedes, this is a process known as pre-chamber ignition, whereby a small chamber is formed inside the cylinder head between the spark plug and the main combustion chamber. This gets filled with a rich fuel mixture. The main combustion chamber gets filled with only a very weak fuel air mix, which would be hard to ignite with a conventional spark plug. When the spark plug ignites the fuel in the pre-chamber, the resulting flame vents through small holes into the main combustion chamber, which then burns the weak fuel mix easily. This creates a long power stroke, despite the largely weak fuel mix.

Such technology requires a very different cylinder head architecture, along with special fuel injectors, spark plugs and – critically – special fuel, to be able to react to the unusual combustion process.

Honda have earmarked development tokens to be spent in Malaysia to allow a big upgrade to the engine. With the turbo, MGU and inlet system all now optimal, it’s expected that a lean burn technology will be the result of this development. This will ultimately bring Honda closer into line with its rivals, allowing them to push the engine for maximum power throughout the race, rather than having to curb its performance to manage the fuel available. This could be the key that unlocks the McLaren-Honda’s potential.

How many tokens are left for 2016 now?