Stupid things non petrolheads say... Vol 2
Discussion
Pebbles167 said:
Two different colleagues were confused by engine sizes recently. One in his Vauxhall Movano loan van claimed it had a 3.5 litre, another said his brother just bought a 5.5 litre Audi A6. They each had the numbers '3500' and '55' on the back respectively, so was easy to see that it was an innocent enough mistake and not just bulls
t.
That daft Audi nomenclature is nonsensical and deceptive. Putting the actual power output on a little badge would be a lot less confusing.t.Pan Pan Pan said:
Exactly. Heavy cars require more energy to accelerate them up to a required speed, than is needed for a light car. That is why F1 and many other competition cars, tend to be lighter rather than heavier, as they are generally faster, and easier to accelerate, stop, and get around bends.
I see you are still at it.The electric car pictured below has a 100 kWh battery, and, like all EVs, is fitted with regenerative braking.
100 kWh is the same amount of energy contained in 10 litres of diesel.
Last year the car drove from Stuggart to Silverstone, covering 747 miles at an average speed of over 50 mph.
It was not recharged once during the journey.
The car has a kerb mass of 1750 kg.
With 2 people on board, that's over 4000 lbs.
Do you have any explanation at all as to how a near 2 ton car managed to cover that distance with the equivalent of just over 2 gallons of diesel, which would equate to well over 300 mpg?
Please spare me the haulage firm analogy, that one is getting really boring, as well as being completely irrelevant.
GT9 said:
Pan Pan Pan said:
Exactly. Heavy cars require more energy to accelerate them up to a required speed, than is needed for a light car. That is why F1 and many other competition cars, tend to be lighter rather than heavier, as they are generally faster, and easier to accelerate, stop, and get around bends.
I see you are still at it.The electric car pictured below has a 100 kWh battery, and, like all EVs, is fitted with regenerative braking.
100 kWh is the same amount of energy contained in 10 litres of diesel.
Last year the car drove from Stuggart to Silverstone, covering 747 miles at an average speed of over 50 mph.
It was not recharged once during the journey.
The car has a kerb mass of 1750 kg.
With 2 people on board, that's over 4000 lbs.
Do you have any explanation at all as to how a near 2 ton car managed to cover that distance with the equivalent of just over 2 gallons of diesel, which would equate to well over 300 mpg?
Please spare me the haulage firm analogy, that one is getting really boring, as well as being completely irrelevant.
What The Deuces said:
As I originally said, Regen is more effective in heavier cars. I doubt that would have been achievable had the kerb mass been 2000lbs all up
Hang on a minute, are you saying a lighter car would have worse economy 
There is indeed a similar looking very-low-drag car with a small diesel engine and a small battery to allow for the use of regenerative braking.
The VW XL1 has a kerb mass of only 800 kg, less than half the Mercedes EQXX I referenced.
The XL1 achieved a real-world economy of around 120 mpg.
As soon as you add a combustion engine into the equation, the real-world economy goes to s
t (comparatively).And no amount of regen, mass savings or low-drag aero will get you anywhere near what a pure EV can achieve.
What The Deuces said:
As I originally said, Regen is more effective in heavier cars. I doubt that would have been achievable had the kerb mass been 2000lbs all up
Having to decelerate a heavier load does not automatically equate to increased effective.How is that energy harvested and what percentage of that energy can be used to recharge the batteries or any other energy store?
As many EVs only have 2 driven wheels that automatically restricts the energy recuperation potential especially if those driven wheels are the rear ones and deceleration (braking) is very much front loaded.
Electric cycles incorporate regeneration so clearly even at low weights it is worthwhile.
I cannot see how a logical conclusion can be drawn that the heavier the vehicle the more efficient the regeneration is as that same load still has to be accelerated again. It is energy overall that matters.
GT9 said:
What The Deuces said:
As I originally said, Regen is more effective in heavier cars. I doubt that would have been achievable had the kerb mass been 2000lbs all up
Hang on a minute, are you saying a lighter car would have worse economy I'm saying Regen is more effective in heavier cars
Lighter cars would obviously be more efficient in the first place... but in a heavier car regen would recover a higher percentage of energy spent than in a lighter car....... not saying that the overall system of a lighter car wouldn't be more efficient because it invariably would be
Edited by What The Deuces on Monday 24th April 09:22
Edited by What The Deuces on Monday 24th April 09:25
GT9 said:
I see you are still at it.
The electric car pictured below has a 100 kWh battery, and, like all EVs, is fitted with regenerative braking.
100 kWh is the same amount of energy contained in 10 litres of diesel.
Last year the car drove from Stuggart to Silverstone, covering 747 miles at an average speed of over 50 mph.
It was not recharged once during the journey.
The car has a kerb mass of 1750 kg.
With 2 people on board, that's over 4000 lbs.
Do you have any explanation at all as to how a near 2 ton car managed to cover that distance with the equivalent of just over 2 gallons of diesel, which would equate to well over 300 mpg?
Please spare me the haulage firm analogy, that one is getting really boring, as well as being completely irrelevant.
As is a car not on sale yet The electric car pictured below has a 100 kWh battery, and, like all EVs, is fitted with regenerative braking.
100 kWh is the same amount of energy contained in 10 litres of diesel.
Last year the car drove from Stuggart to Silverstone, covering 747 miles at an average speed of over 50 mph.
It was not recharged once during the journey.
The car has a kerb mass of 1750 kg.
With 2 people on board, that's over 4000 lbs.
Do you have any explanation at all as to how a near 2 ton car managed to cover that distance with the equivalent of just over 2 gallons of diesel, which would equate to well over 300 mpg?
Please spare me the haulage firm analogy, that one is getting really boring, as well as being completely irrelevant.
What The Deuces said:
No
I'm saying Regen is more effective in heavier cars
Lighter cars would obviously be more efficient in the first place... but in a heavier car regen would recover a higher percentage of energy spent than in a lighter car....... not saying that the overall system of a lighter car wouldn't be more efficient because it invariably would be
Could you show your working to evidence please as I do not see the logic in your statement. I'm saying Regen is more effective in heavier cars
Lighter cars would obviously be more efficient in the first place... but in a heavier car regen would recover a higher percentage of energy spent than in a lighter car....... not saying that the overall system of a lighter car wouldn't be more efficient because it invariably would be
Edited by What The Deuces on Monday 24th April 09:22
Edited by What The Deuces on Monday 24th April 09:25
Have you taken into account the extra losses of the heavier vehicle? e.g. drive train losses, friction and drag.
GT9 said:
So an engineering feat is not valid because you can't buy the car, righto.
PPP is stuck in a parallel universe where the ONLY thing that affects a car's performance is its kerb mass.
Just trying to bring him back to planet earth.
No different to EV fans trying to make out that 2000kg cars are going to be 'fun' and not a compromise. PPP is stuck in a parallel universe where the ONLY thing that affects a car's performance is its kerb mass.
Just trying to bring him back to planet earth.
You are not impartial on the subject, so probably aren't the right judge?
Nomme de Plum said:
What The Deuces said:
As I originally said, Regen is more effective in heavier cars. I doubt that would have been achievable had the kerb mass been 2000lbs all up
Having to decelerate a heavier load does not automatically equate to increased effective.How is that energy harvested and what percentage of that energy can be used to recharge the batteries or any other energy store?
As many EVs only have 2 driven wheels that automatically restricts the energy recuperation potential especially if those driven wheels are the rear ones and deceleration (braking) is very much front loaded.
Electric cycles incorporate regeneration so clearly even at low weights it is worthwhile.
I cannot see how a logical conclusion can be drawn that the heavier the vehicle the more efficient the regeneration is as that same load still has to be accelerated again. It is energy overall that matters.
I suppose efficiency would be rated by identifying how much of the energy can be recovered. EV's can ignore using the brakes at all, in favour of increased regeneration force. At some point, that system can't recover energy at the required rate to stop the vehicle and will use the brakes to turn the kinetic energy to waste energy. I'm not intelligent enough to know the ins and outs of how each manufacturer deals with regen or how capable their chosen methods and components are.
Nomme de Plum said:
Could you show your working to evidence please as I do not see the logic in your statement.
Have you taken into account the extra losses of the heavier vehicle? e.g. drive train losses, friction and drag.
Just consider which of those are directly influenced by massHave you taken into account the extra losses of the heavier vehicle? e.g. drive train losses, friction and drag.
RazerSauber said:
A heavier vehicle will have more kinetic energy so there is more energy available to regenerate with, but that's obviously offset by the increase in energy to get a heavier object moving.
I suppose efficiency would be rated by identifying how much of the energy can be recovered. EV's can ignore using the brakes at all, in favour of increased regeneration force. At some point, that system can't recover energy at the required rate to stop the vehicle and will use the brakes to turn the kinetic energy to waste energy. I'm not intelligent enough to know the ins and outs of how each manufacturer deals with regen or how capable their chosen methods and components are.
There is the limiting factor of the absorption of the energy recovery and storage in the batteries. I suppose efficiency would be rated by identifying how much of the energy can be recovered. EV's can ignore using the brakes at all, in favour of increased regeneration force. At some point, that system can't recover energy at the required rate to stop the vehicle and will use the brakes to turn the kinetic energy to waste energy. I'm not intelligent enough to know the ins and outs of how each manufacturer deals with regen or how capable their chosen methods and components are.
It's pretty clear that a fully loaded HGV will have way more kinetic energy than any car but not really very relevant.
The question is what percentage of the energy can be recovered and recycled not the absolute number.
carlo996 said:
You are not impartial on the subject, so probably aren't the right judge?
What makes you say that. I've got more petrol coursing through my veins than most.
I absolutely love interesting petrol cars.
I'm even more passionate about engineering excellence, which I hope you are too, given your profession.
I post on this topic when I read poor or plainly incorrect assumptions about all drivetrains.
And, yes, especially electric ones.
What The Deuces said:
Nomme de Plum said:
Could you show your working to evidence please as I do not see the logic in your statement.
Have you taken into account the extra losses of the heavier vehicle? e.g. drive train losses, friction and drag.
Just consider which of those are directly influenced by massHave you taken into account the extra losses of the heavier vehicle? e.g. drive train losses, friction and drag.
Nomme de Plum said:
What The Deuces said:
As I originally said, Regen is more effective in heavier cars. I doubt that would have been achievable had the kerb mass been 2000lbs all up
Having to decelerate a heavier load does not automatically equate to increased effective.How is that energy harvested and what percentage of that energy can be used to recharge the batteries or any other energy store?
As many EVs only have 2 driven wheels that automatically restricts the energy recuperation potential especially if those driven wheels are the rear ones and deceleration (braking) is very much front loaded.
Electric cycles incorporate regeneration so clearly even at low weights it is worthwhile.
I cannot see how a logical conclusion can be drawn that the heavier the vehicle the more efficient the regeneration is as that same load still has to be accelerated again. It is energy overall that matters.
For normal driving, having rear-only regen isn't much of an issue. Just brake lighter and earlier and not engage the friction brakes (if they're using series vs parallel braking).
Nomme de Plum said:
What The Deuces said:
Nomme de Plum said:
Could you show your working to evidence please as I do not see the logic in your statement.
Have you taken into account the extra losses of the heavier vehicle? e.g. drive train losses, friction and drag.
Just consider which of those are directly influenced by massHave you taken into account the extra losses of the heavier vehicle? e.g. drive train losses, friction and drag.
Drag.... if i load up my van the drag doesn't increase.
Yes some frictional losses may increase but not at the same % as the increase in mass
I hope the degrees are a bit better these days
Gassing Station | General Gassing | Top of Page | What's New | My Stuff