Audi Dakar racer

[cjc_td5]

I'm interested in what Audi is doing in the current Dakar with its hybrid. It's hard to get too many details, but one note is that by optimising the engine to spin a generator only (rather than have to work a rev range spinning a gearbox) they recon they can get fuel efficiencies to only have to carry 300l of fuel vs 600l that the other ICE vehicles carry?

They've also only got about 50kwh of batteries onboard?

[Arapiles]

I'm interested in what Audi is doing in the current Dakar with its hybrid. It's hard to get too many details, but one note is that by optimising the engine to spin a generator only (rather than have to work a rev range spinning a gearbox) they recon they can get fuel efficiencies to only have to carry 300l of fuel vs 600l that the other ICE vehicles carry?

They've also only got about 50kwh of batteries onboard?


That's how Nissan's e-Power engines work: their e-Note hatchback (which is Corolla sized) can apparently get 2.9 l/100km:

J-Spec Imports (http://www.j-spec.com.au/lineup/Nissan/Note/e-Power_HE12/id-D17)

NB, as the above mentions, that works out at about 1500km to a 50 - 60 litre fuel tank.

It's also lower fuel use than most normal hybrids.

[cjc_td5]

I recall discussion on range extenders on here previously that there was too much efficiency loss in the mechanical - electric - battery - electric - mechanical process to be competitive against conventional mechanical drivetrains?? This Audi seems to have made progress on this?

[Arapiles]

I recall discussion on range extenders on here previously that there was too much efficiency loss in the mechanical - electric - battery - electric - mechanical process to be competitive against conventional mechanical drivetrains?? This Audi seems to have made progress on this?


The discussions I've read state that it's more efficient to have an ICE in a car running a generator than running the wheels. One of the factors is probably that when used to run a generator the ICE is always running at the optimum revs for fuel efficiency and not at the RPM required for the speed the car's running at.

It may be that the "normal" range extender arrangement (which is the ICE chiming in to run the wheels when the battery runs out) is less efficient than disconnecting the ICE from the wheels and using it only to run a generator. I have a vague recollection that the Holder Volt may have done both - i.e., in some circumstances the ICE ran the wheels.

In either case, Nissan has been doing for a couple of years what it sounds like Audi is doing with their Dakar vehicle.

NB, we seriously considered importing an e-Note through J.Spec.


Edit: it appears that Nissan will import an e_Power car into Australia this year. The attached article has some diagrams showing the different arrangements:

Nissan e-Power coming to Australia in 2022, Qashqai hybrid possible - Chasing Cars (https://www.chasingcars.com.au/news/future-cars/nissan-e-power-coming-to-australia-in-2022-qashqai-hybrid-possible/)


https://www.chasingcars.com.au/wp-content/uploads/2021/08/Nissan-e-Power-2022-3.jpg

[Arapiles]

Nissan e-POWER technology explained - YouTube (https://www.youtube.com/watch?v=T5wCppCiQE8&t=122s)

[Arapiles]

Double post

[cjc_td5]

A really quick google found one industrial 50kW gen set with a 3.4l turbo diesel, with a fuel burn rate of 4l/hr at max load. The engine size is about what I would expect. The fuel burn is 1/3-1/2 of what would be expected of a conventional mechanical drive train.

I would have thought that around 50kw ICE generation supplemented by up to 50kwh of battery, would move things along quite satisfactorily?

[Arapiles]

Audi says that it's a 52kWh battery:

Rallye Dakar: The high-voltage battery in the Audi RS Q e-tron | Audi MediaCenter (https://www.audi-mediacenter.com/en/press-releases/rallye-dakarthe-high-voltage-battery-in-the-audi-rs-q-e-tron-14453)

I can't see the output of the 2.0 litre ICE listed anywhere.

Edit: no output, but it operates between 4,500 - 6000 RPM:


Since the combustion engine is operated in the particularly efficient range of between 4,500 and 6,000 rpm, the specific consumption is well below 200 grams per kWh.

Audi RS Q e-tron: Test laboratory for possible future technologies at the Dakar Rally | Audi MediaCenter (https://www.audi-mediacenter.com/en/press-releases/audi-rs-q-e-tron-test-laboratory-for-possible-future-technologies-at-the-dakar-rally-14118)

According to this, they ran out of petrol on one stage and did the last 45km on battery only: that'd suggest that it would usually have the ICE running and not cycling on and off (because I wouldn't expect that you'd get more than 100km at race speeds out of a battery only a little bit bigger than a Leaf's):

Audi'''s EV Dakar Rally Car Is Resurrecting the Range Extender | WIRED UK (https://www.wired.co.uk/article/audi-ev-dakar-rally-car)

It's also interesting that the return to range extender technology is being explained by a dawning realisation that a wholly electric car fleet may not be possible due to the need to increase electricity generation, so this is very much a transitional technology.

[chuck]

Elevated work platforms have been using this technology for years.

All electric with small diesel motor to run generator to charge batteries when required.

Could never figure out why car manufactures did not go down that path.

Can still charge using GPO when practical i.e. at night when EWP is not being used.

[Xtreme]

I know it's not Land Rover but pretty impressive performance.

Mission accomplished | Audi Magazine Australia (https://magazine.audi.com.au/article/mission-accomplished?utm_campaign=AA-01-2022-MAG_HIGHLIGHTS_January.topCTA&utm_medium=email&utm_source=sfmc&utm_content=0032e0000082lNpAAI&j=665817&sfmc_sub=384909676&l=68_HTML&u=19074237&mid=100040973&jb=1164)

[cjc_td5]

Yes I think it is an interesting development of the technology. Basically half the fuel consumption of the conventional drivetrain vehicles.
I tried to kick start a conversation re this vehicle here.

Audi Dakar racer (https://www.aulro.com/afvb/alternate-energies/289594-audi-dakar-racer.html)

[Xtreme]

Sorry, I didn't see your other thread.
Mods might like to merge the two threads.

[cjc_td5]

I saw a youtube video the other day of the range extender unit screaming its bells off when the vehicle was parked up between a stage. Would be a bit disconcerting...