Horsepower of the engines.

[Sixbarboost]

Please explain, the ES power can only be used through the 120 kW MGU-K, no?

[bergie88]

Please explain, the ES power can only be used through the 120 kW MGU-K, no?

Also by the MGU-H to assist the turbo when it is not delivering the desired boost through exhaust gasses only (the well-known turbo lag)

[Sixbarboost]

Still don't get it, even with 40% efficiency from the ICE with 45 MJ/kg, it's no more than 500 kW plus 120 in total?

[gruntguru]

...... in "qualy mode" where the ES is driving both the MGUK and the supercharger (via MGUH) allowing the wastegate to be open and zero exhasut backpressure on the engine.
In one sense the MGUH is actually driving the crankshaft in "qualy mode" - powering the supercharger which in turn pushes down on the pistons during the intake stroke (the more boost the better in this mode) without the parasitic pressure normally applied to the pistons during the exhaust stroke.

'the more boost the better' ..... in qualy mode ?
because there's no back pressure, won't the boost needed for a given air massflow be lower ?

how about running the ICE (part-wastegated?) as a turbocharged engine only ? - this also lowers the backpressure
(combining this with 120 kW motoring from the mgu-k and ES of course)

In supercharged mode, every bar of additional boost is approx. 1 bar increase in BMEP. Likewise 1 bar BP reduction = 1 bar BMEP increase. Sure the air massflow will increase but clever manipulation of the DI strategy could still produce an ideal AFR in the rich (stratified) zone.

[gruntguru]

Still don't get it, even with 40% efficiency from the ICE with 45 MJ/kg, it's no more than 500 kW plus 120 in total?

620 kW = 825 hp. On top of that, if the MGUH is briefly used to power the supercharger, the wastegate can be opened and the ICE operated with no exhaust back pressure allowing it to produce more power at the crankshaft. This is what I refer to as "qualy mode".

[Tommy Cookers]

...... in "qualy mode" where the ES is driving both the MGUK and the supercharger (via MGUH) allowing the wastegate to be open and zero exhasut backpressure on the engine.
In one sense the MGUH is actually driving the crankshaft in "qualy mode" - powering the supercharger which in turn pushes down on the pistons during the intake stroke (the more boost the better in this mode) without the parasitic pressure normally applied to the pistons during the exhaust stroke.

'the more boost the better' ..... in qualy mode ?
because there's no back pressure, won't the boost needed for a given air massflow be lower ?

how about running the ICE (part-wastegated?) as a turbocharged engine only ? - this also lowers the backpressure
(combining this with 120 kW motoring from the mgu-k and ES of course)

In supercharged mode, every bar of additional boost is approx. 1 bar increase in BMEP. Likewise 1 bar BP reduction = 1 bar BMEP increase. Sure the air massflow will increase but clever manipulation of the DI strategy could still produce an ideal AFR in the rich (stratified) zone.

again, why not run the ICE 'part-wastegated' ie as a turbocharged engine .......

running fully wastegated is disproportionately expensive in ES energy
gg talks of 80 kW for the compressor but has ignored the additional WASTE OF POWER turning the turbine ??
(it's not isolated in vacuum or in a sealed circulatory system ? )
ie total ES power required by the mgu-h for FW running is maybe 120 kW or more ??? (ie total ES power maybe 240 kW or more ?)

so as a trading of stored electrical power for mechanical power, FW running is surely less efficient than has been presented ?

but as this sized turbine will drive the compressor with relatively low BPs
such 'partially wastegated' running will surely give a more efficient use of ES power (total ES power is 120 kW)

with this PW running the temporary power output will not be quite as high as with FW running, but it will last much longer
and so give to a qually lap the greatest energy boost (ie more than FW will), and so give the fastest laptime
ie the greater 'bang per ES buck'
and similarly so in the race

[bergie88]

In supercharged mode, every bar of additional boost is approx. 1 bar increase in BMEP. Likewise 1 bar BP reduction = 1 bar BMEP increase. Sure the air massflow will increase but clever manipulation of the DI strategy could still produce an ideal AFR in the rich (stratified) zone.

again, why not run the ICE 'part-wastegated' ie as a turbocharged engine .......

running fully wastegated is disproportionately expensive in ES energy
gg talks of 80 kW for the compressor but has ignored the additional WASTE OF POWER turning the turbine ??
(it's not isolated in vacuum or in a sealed circulatory system ? )
ie total ES power required by the mgu-h for FW running is maybe 120 kW or more ??? (ie total ES power maybe 240 kW or more ?)

so as a trading of stored electrical power for mechanical power, FW running is surely less efficient than has been presented ?

but as this sized turbine will drive the compressor with relatively low BPs
such 'partially wastegated' running will surely give a more efficient use of ES power (total ES power is 120 kW)

with this PW running the temporary power output will not be quite as high as with FW running, but it will last much longer
and so give to a qually lap the greatest energy boost (ie more than FW will), and so give the fastest laptime
ie the greater 'bang per ES buck'
and similarly so in the race

Surely there is a tradeoff between reducing backpressure and needed power from the MGU-H when the wastegate is opened. The sweet spot of this tradeoff can be found by simulations and on the test bench, no wonder a lot of simulation engineers and test benches are working almost non-stop at the factories.

About MGU-H power to provide the needed boost pressure, I think you are overestimating the number a bit. The only thing it has to do is to pump air to a certain pressure, which is limited because of the fuel flow limit (if I am correct?). I think it needs no more than around 50kW, but I am not sure.

[Tommy Cookers]

I used gg's value, in his post P22 of the TERS thread he gave 83.5 kW with 80% efficiency at his PR of 3.3
(75% efficiency would need 90kW, and Brayton power would be about 32 kW, far less than the blowdown power)

anyway the main point is the electrical power wasted turning the turbine, which to me seems unaccounted for

[gruntguru]

In supercharged mode, every bar of additional boost is approx. 1 bar increase in BMEP. Likewise 1 bar BP reduction = 1 bar BMEP increase. Sure the air massflow will increase but clever manipulation of the DI strategy could still produce an ideal AFR in the rich (stratified) zone.

again, why not run the ICE 'part-wastegated' ie as a turbocharged engine .......

running fully wastegated is disproportionately expensive in ES energy
gg talks of 80 kW for the compressor but has ignored the additional WASTE OF POWER turning the turbine ??
(it's not isolated in vacuum or in a sealed circulatory system ? )
ie total ES power required by the mgu-h for FW running is maybe 120 kW or more ??? (ie total ES power maybe 240 kW or more ?)

so as a trading of stored electrical power for mechanical power, FW running is surely less efficient than has been presented ?

but as this sized turbine will drive the compressor with relatively low BPs
such 'partially wastegated' running will surely give a more efficient use of ES power (total ES power is 120 kW)

with this PW running the temporary power output will not be quite as high as with FW running, but it will last much longer
and so give to a qually lap the greatest energy boost (ie more than FW will), and so give the fastest laptime
ie the greater 'bang per ES buck'
and similarly so in the race

I agree, the turbine is not runnng in a vacuum. On the other hand, with the wastegate(s) wide open (have you seen how massive the wastegate ducts are?) the turbine will still be passing some of the exhaust. In particular, the blowdown pulses will tend to take the straighter path to the turbine and impinge on the blade tips. I can imagine there being very little parasitic drag under those conditions.

I emphasised the wastegate size to make a point. They are much larger than what would be needed to merely control boost - suggesting that zero back pressure (when in "qualy mode") is the goal.

[Blackout]

Have you some pics of the 2015 wastegates? the 2014 Ferrari ones looked huge but have no clear pics of the 2014 Merc one. The 2014 Renault WG pipes looked very thin (except the Lotus E22).

[Blackout]

Many people say some 2015 wastegates and tehir related pipes look huge, similar to the F14T engine...
Another question, is it possible to make the wastegate completely bypass the turbine? I mean make it pass over 95per100 of the gases?

[bergie88]

Many people say some 2015 wastegates and tehir related pipes look huge, similar to the F14T engine...
Another question, is it possible to make the wastegate completely bypass the turbine? I mean make it pass over 95per100 of the gases?

The exhaust manifold will be designed to optimize the gasflow from the cylinders to the turbine wheel so there will always be some impulses on the turbine wheel, but when the wastegate is fully open almost all the gases wil bypass the turbine. CFD analysis or measurements will be needed to provide numbers on it, but I think it will be somewhere between 85 and 95 percent or something. Anyone here with some experience on this?

[adriannewey9864]

they need have be 1150 HP petrol part of engine, and 350 HP electric part

[Brian Coat]

This month's Race Engine Technology speculates Merc ICE hp at 700 bhp, "speculation based partly on the observations of rival power unit developers". Naturally Mr Cowell was neither dismissive nor confirmatory!

Other things I found interesting in the article:

Force India claims they don't use Merc's air-air+water-air double inter cooler system because they cannot afford the cost of offsetting the weight penalty.

Andy Cowell says all Merc's improvement at Canada was mapping, based partly on durability knowledge/confidence gained in the first part of the season.

[Blackout]

All ways lead to those numbers; around 700hp for the most powerful ICE and around 630 for the least powerful...
What do they mean with "Merc's air-air+water-air double inter cooler system?" Is merc using a classic sidepod-placed a-a intercooler in addition to their 'monocoque-integrated' w-a intercooler?