RE: Final EU vote on 2035 engine phaseout delayed
Discussion
500TORQUES said:
GT9 said:
Yes, because it get to higher speeds.
Energy is definitely lost to drag, yes.
That energy on a per unit distance basis increases with the square of the speed you are travelling at.
Energy is also lost to rolling resistance, and is approximately the same value on a per unit distance basis, regardless of speed.
Energy is also lost to friction braking, which is the car's kinetic energy converted to heat.
Now if you can retrieve that kinetic energy, rather than heating the brakes, .....wellllllll that's called regenerative braking.
The kinetic energy is a function of the square of speed.
Regardless of how fast you accelerated to a given speed, the kinetic energy is the same.
The rate of acceleration determines the power required to add kinetic energy and is governed by this rule of thumb: 6 bhp per ton per g per mph.
That's the crucial bit that you missed and what led to the whole latest exchange of post.
And of course, energy is also lost to the inefficiency of the drivetrain, which is where the EV makes its greatest gains over ICE, combined with the benefits of regenerative mentioned above.
The single largest loss of energy in an ICE goes straight from the engine to the atmosphere via the radiator or the exhaust, usually about 70% or more of the energy in the fuel.
A lack of understanding of that last sentence seems to be the root cause of so much of the misconception about the difference in energy efficiency between ICEs and EVs.
GT9 said:
The single largest loss of energy in an ICE goes straight from the engine to the atmosphere via the radiator or the exhaust, usually about 70% or more of the energy in the fuel.
A lack of understanding of that last sentence seems to be the root cause of so much of the misconception about the difference in energy efficiency between ICEs and EVs.
Thermal efficiency of coal-fired power stations is around 33% whereas gas-fired plant averages 50%. Electrical energy from these carbon emitting sources is used to power EVs.A lack of understanding of that last sentence seems to be the root cause of so much of the misconception about the difference in energy efficiency between ICEs and EVs.
Puts a dent in their global on-road operating efficiency...
bigothunter said:
Thermal efficiency of coal-fired power stations is around 33% whereas gas-fired plant averages 50%. Electrical energy from these carbon emitting sources is used to power EVs.
Puts a dent in their global on-road operating efficiency...
Correct me if I'm wrong, but coal is only 1% of the UK's supply, so barely worth considering, and gas accounts for around 40%, a number which I'd guess will gradually reduce. I'm pretty sure that would still put the EV's on-road efficiency miles ahead of an ICE?Puts a dent in their global on-road operating efficiency...
TheBinarySheep said:
bigothunter said:
Thermal efficiency of coal-fired power stations is around 33% whereas gas-fired plant averages 50%. Electrical energy from these carbon emitting sources is used to power EVs.
Puts a dent in their global on-road operating efficiency...
Correct me if I'm wrong, but coal is only 1% of the UK's supply, so barely worth considering, and gas accounts for around 40%, a number which I'd guess will gradually reduce. I'm pretty sure that would still put the EV's on-road efficiency miles ahead of an ICE?Puts a dent in their global on-road operating efficiency...
You are correct, BH likes to be otherwise now and again.
He is also overlooking the fact the petrol does not arrive at the pumps without a fairly significant upstream energy consuming chain of events.
For the present UK mix of renewables vs fossil fuels, the effect of the losses in the fossil fuel electricity supply chain and their proportional contribution to overall electricity generation effectively 'cancels out' the ICE upstream fossil fuel supply chain, which is of course a 100% proportional contribution.
What that means is that it is valid in the UK to compare tank-to-wheel efficiency for the ICE vs battery-to-wheel efficiency for the EV and just ignore the upstream stuff.
In 2030 and beyond the efficiency gap will grow significantly in favour of the EV due to a higher mix of renewables.
TheBinarySheep said:
bigothunter said:
Thermal efficiency of coal-fired power stations is around 33% whereas gas-fired plant averages 50%. Electrical energy from these carbon emitting sources is used to power EVs.
Puts a dent in their global on-road operating efficiency...
Correct me if I'm wrong, but coal is only 1% of the UK's supply, so barely worth considering, and gas accounts for around 40%, a number which I'd guess will gradually reduce. I'm pretty sure that would still put the EV's on-road efficiency miles ahead of an ICE?Puts a dent in their global on-road operating efficiency...
Oil Price said:
Back in 1973, when total global energy supply was more than half the current supply, coal held a share of 24.5 percent of global energy supply, while oil accounted for the largest share at 46.2 percent, according to IEA’s estimates.
In 2018, the share of coal increased to 26.9 percent, while oil’s share of global energy supply dropped to 31.6 percent. The share of natural gas rose from 16 percent in 1973 to 22.8 percent in 2018, IEA’s statistics show.
As much as 64 percent of the newly commissioned coal capacity was in China, another 12 percent came from India, and the remaining 24 percent was mainly in Asian countries, including Malaysia, Indonesia, and Pakistan.
https://oilprice.com/Latest-Energy-News/World-News...
In 2018, the share of coal increased to 26.9 percent, while oil’s share of global energy supply dropped to 31.6 percent. The share of natural gas rose from 16 percent in 1973 to 22.8 percent in 2018, IEA’s statistics show.
As much as 64 percent of the newly commissioned coal capacity was in China, another 12 percent came from India, and the remaining 24 percent was mainly in Asian countries, including Malaysia, Indonesia, and Pakistan.
https://oilprice.com/Latest-Energy-News/World-News...
GT9 said:
You are correct, BH likes to be otherwise now and again.
He is also overlooking the fact the petrol does not arrive at the pumps without a fairly significant upstream energy consuming chain of events.
For the present UK mix of renewables vs fossil fuels, the effect of the losses in the fossil fuel electricity supply chain and their proportional contribution to overall electricity generation effectively 'cancels out' the ICE upstream fossil fuel supply chain, which is of course a 100% proportional contribution.
What that means is that it is valid in the UK to compare tank-to-wheel efficiency for the ICE vs battery-to-wheel efficiency for the EV and just ignore the upstream stuff.
In 2030 and beyond the efficiency gap will grow significantly in favour of the EV due to a higher mix of renewables.
Really should not be a matter of right or wrong. Much healthier to consider the whole scenario and reveal hidden baggage carried by ICEV and EV. Don't want EVs to become a doctrine do we?He is also overlooking the fact the petrol does not arrive at the pumps without a fairly significant upstream energy consuming chain of events.
For the present UK mix of renewables vs fossil fuels, the effect of the losses in the fossil fuel electricity supply chain and their proportional contribution to overall electricity generation effectively 'cancels out' the ICE upstream fossil fuel supply chain, which is of course a 100% proportional contribution.
What that means is that it is valid in the UK to compare tank-to-wheel efficiency for the ICE vs battery-to-wheel efficiency for the EV and just ignore the upstream stuff.
In 2030 and beyond the efficiency gap will grow significantly in favour of the EV due to a higher mix of renewables.
Of course ICE fuel supply has energy overheads. But I am not convinced they nullify the penalty of 27% coal-power electricity generation worldwide. That puts matters in a very different perspective.
But I suggest exploring that topic is beyond the intended scope of this thread...
500TORQUES said:
bigothunter said:
That's 0.98g (ok call it 1.0g).
Acceleration rate isn't a constant on a car.But 0-60 mph times are dominated by power/mass especially for powerful cars. Aero drag does not have much significance until higher speeds are reached.
You might record 1.2g peak value due to inertial effects possibly. But it won't be sustained for more than a few milliseconds.
Edited by bigothunter on Sunday 2nd April 20:11
bigothunter said:
For many reasons...
But 0-60 mph times are dominated by power/mass especially for powerful cars. Aero drag does not have much significance until higher speeds are reached.
You might record 1.2g peak value due to inertial effects possibly. But it won't be sustained for more than a few milliseconds.
This is painfull. Traction matters enormously in 0-60 times, so does gear shift speed.But 0-60 mph times are dominated by power/mass especially for powerful cars. Aero drag does not have much significance until higher speeds are reached.
You might record 1.2g peak value due to inertial effects possibly. But it won't be sustained for more than a few milliseconds.
Edited by bigothunter on Sunday 2nd April 20:11
500TORQUES said:
This is painfull. Traction matters enormously in 0-60 times, so does gear shift speed.
You have failed to mention:Weight transfer onto the driven wheels
Advantage of live axle over IRS for initial acceleration
Effect of decelerating a spinning flywheel which supplements engine torque
Reaction time of driver
State of his underpants
The list is endless. In which speed interval does your car achieve 1.2g ?
Does not need to start at zero...
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