18 replies to this topic

[mariner]

Interesting comments from Vettel about the climate change relevance of the F1 hybrid power units

 

https://www.autospor...brids/10310787/

 

I think he has a point as the regen. which boosts economy relies on massive de- acceleration rates which are irrelevant in road cars. Obviously you can harvest power quick and fast or slow and low for same KWH's but , as I understand the whole battery design is different and F1 uses only quick and fast.

 

To throw a retro rock in as well, US Sprint cars develop the same 900 bhp and use 100% non fossil fuel, they only weight 650KG too!

 

 

 

[Magoo]

I think he's mainly correct, but I don't think Formula 1 needs to justify itself in that regard. It's entertaining; it pursues technology in general; and the race cars are hardly an environmental threat in  themselves. The planes and trucks carrying everything and everyone to and from the events no doubt have a far greater footprint. 

[Greg Locock]

If you could manage 600 kW regen then you could do away with mechanical brakes, but designing your whole electronic drive system around a once in 5 years event is not cost effective for road cars.

[gruntguru]

I am sure the vast majority of braking energy is dissipated in urban driving and at a speed and decel where most EV/HEV systems have sufficient retardation power.

 

The value of the MGUH is far more questionable - road cars operate at sufficiently high power levels for only a small fraction of the time.

Edited by gruntguru, 27 May 2022 - 04:05.

[Greg Locock]

95% of braking events are 0.3g or less, as a rule of thumb. Old school batteries didn't like being charged at 100s of kW, so it didn't really come up. Worst case is coming down a mountain and braking from high speed, there's some mountain pass in Italy that is the usual standard for brakes. Oh, I forgot, you can't totally rely on regen because if your battery is at 100% then you can't brake. So given you have to have mechanical brakes, it just becomes a tradeoff.

[Henri Greuter]

Interesting comments from Vettel about the climate change relevance of the F1 hybrid power units

 

https://www.autospor...brids/10310787/

 

I think he has a point as the regen. which boosts economy relies on massive de- acceleration rates which are irrelevant in road cars. Obviously you can harvest power quick and fast or slow and low for same KWH's but , as I understand the whole battery design is different and F1 uses only quick and fast.

 

To throw a retro rock in as well, US Sprint cars develop the same 900 bhp and use 100% non fossil fuel, they only weight 650KG too!

And how much kgs of that 100% non fossil fuel ( Methanol I assume....) do they need for running the same distance as an F1 car? (Adding up to the starting weight...)

 

Or phrased differently;

If both cars have the same fuel tank capacity: how much distance will that US sprint car cover on a full fuel tank compared with the F1 car????

[mariner]

I am very sure the MPG of a Sprint car is much worse than F1 car but that really isn't relevant because Sprint car races are very short, sometimes only 5 miles and not more than 40 miles ( i.e 80 laps of a1/2 mile oval.)

 

As the whole race meeting takes place in 4- 5 hours with the same 30 or so cars re- running in heats etc. the overall environmental cost per race meeting  is smaller than 3 days of F1 with several hundred laps per car around a 2- 3mile track in many cases.

 

It doesn't mean one is beter than teh other - jsut diferent.

[Henri Greuter]

I am very sure the MPG of a Sprint car is much worse than F1 car but that really isn't relevant because Sprint car races are very short, sometimes only 5 miles and not more than 40 miles ( i.e 80 laps of a1/2 mile oval.)

 

As the whole race meeting takes place in 4- 5 hours with the same 30 or so cars re- running in heats etc. the overall environmental cost per race meeting  is smaller than 3 days of F1 with several hundred laps per car around a 2- 3mile track in many cases.

 

It doesn't mean one is beter than teh other - jsut diferent.

Several hundred laps per car around a 2 - 3 mile in many cases?

 

Well, is 2 means several for you....

But I think you would be surprised about the number of occasions that any driver will turn more than 200 laps combined in all practice and qualifaying sessions and the race combined in an event during an entire season. Only the events on a very short track with high numbers of laps for the full race distance sich as Monaco, Austria and Zandvoort  you might get close to and perhaps beyond 200.

And I dare to take just about a bet on anything you offer for a driver making more than 300 laps in a race weekend that you won't find such an occasion to happen.

[Wuzak]

Monaco - 20-30 laps per practice session. Let's use the lower end - 3 x 20 = 60 laps.

 

12-15 laps in qualifying. Depending on how far in qualifying the driver proceeds. Let's call it 15 - 1 run in Q1, 2 runs in Q2 and Q3.

 

Race is (scheduled) 77 laps. Total 152 laps.

 

Of course, many of those laps in practice and qualifying will be at much less than full pace.

 

On longer tracks the numbers will be much smaller (except qualifying).

[gruntguru]

At a given power output a methanol sprintcar will consume fuel at four times the rate of an F1 eg at 700 hp the sprintcar uses about 300 kg/hr and the F1 about 80 kg/hr.

[ray b]

95% of braking events are 0.3g or less, as a rule of thumb. Old school batteries didn't like being charged at 100s of kW, so it didn't really come up. Worst case is coming down a mountain and braking from high speed, there's some mountain pass in Italy that is the usual standard for brakes. Oh, I forgot, you can't totally rely on regen because if your battery is at 100% then you can't brake. So given you have to have mechanical brakes, it just becomes a tradeoff.

why not power brake with a full battery

when we race slot cars an added small battery was used to boost the regen braking

effect of freewheeling then adding a bit of reverse as needed to slow

 

so no need for pure mechanical brakes unless by rule

[gruntguru]

why not power brake with a full battery

There is no such thing.

The braking energy has to go somewhere. You can either heat up the motor, heat up some wiring somewhere or charge the battery (not possible with a full battery).

Edited by gruntguru, 15 June 2022 - 20:39.

[Greg Locock]

You'd end up with a red hot motor if you are implying short circuiting the motor, which certainly can be used. You are putting a car's worth of KE into 50 kg of copper, very toasty. But yes, it is an approach that can be used at some scales.

[just me again]

Diesel electric locomotives, brake 2500tons trains with the electric motors without batteries. So it can be done. You just have to turn the braking in to heat.

[mariner]

Diesel  electric locos use "dynamic braking" which simply heats up big wire grids on the roof , cooled by large fans.

 

It is not regen and it is wasting kinetic energy as heat.

 

It is not used so much to stop a  train as to keep it's speed to a safe constant on long declines.

 

Fi you go train spotting in a hilly US state you will hear a very loud whining noise which is the dynamic brakes at work.

 

Very similar tot the well known truck/bus Telma retarder .

Edited by mariner, 16 June 2022 - 19:20.

[just me again]

It is wasting energy. But it shows that you can brake electric, even when the battery are full. So if you want. You can do without normal brakes!

[gruntguru]

You haven't said where you are going to put the waste energy? As Greg said, you can do away with your friction brakes as long as you have somewhere to put 600 kW. Delete four brake discs and calipers and replace with a 600 kw fan heater and ducting?

 

Here's a 125 kW fan heater. 

 

https://www.alibaba.....f5545e7arNMUvo

Edited by gruntguru, 18 June 2022 - 05:04.

[Fat Boy]

It is wasting energy. But it shows that you can brake electric, even when the battery are full. So if you want. You can do without normal brakes!

I can play "Yankee Doodle Dandy" on my armpit, but that fact hardly makes it the preferred method of musical expression.

[Ross Stonefeld]

We get the right producer, a Name, call it a remix and...