Will We Have a 100-mpg Car Soon?

[sentiententity]

My 77 year old neighbour only has one leg, so cycling 2.7 miles to church is possibly not an option, whereas an automatic Smart car is

Cue violins as evil econut forces one-legged old lady to cycle to church. Not. Did you read either of my previous posts? I said MOST journeys, NEVER "all".

What about the other points/questions I had?

s.

[clv101]

clv101 said:

I don't understand this. 100mpg is almost twice 55mpg. How does a different battery pack manage to get almost twice the work out of the same fuel? The engine is the same, the duty cycle can be improved a bit, but I wouldn't have thought anywhere near a doubling.

The standard battery and electric motor can run the car for around 3 miles without using the gasoline motor, after which the battery has run down, causing the gasoline motor to start up to recharge the battery. The lithium battery can power the car for around 30 miles without using the gasoline motor. The clue is in the term MPG ...the car is basically travelling more miles without using gasoline, hence increased MPG.

No - it doesn't work like that. You need to think about the total amounts of energy involved. All the energy comes from the petrol. The Li battery just stores more than the originals. All the larger battery store does for you is allow for a more optimum duty cycle from engine.

There are serious diminishing returns on investment here so I'll wager than the battery swap improves the mpg by no more than 10% on average.

[PS_RalphW]

No...clv101's question is a good one. There is a lot more useful energy coming from somewhere in the Li battery scenario: where from? Does the Li battery hold a lot more charge than the standard one? If that is all, it's not really improved mpg, because extra gas must be burnt to charge the battery, surely? (albeit burnt on the previous journey, so that you start your efficiency test with a full battery). Or is the system more efficient for some reason, that is, energy contained in the petrol was wasted as heat with the old battery, but this energy is usable with the Li ion battery? There is a massive claim of improved efficiency here, which seems unlikely without a reduction in vehicle weight, improvement in aerodynamics, etc.

s.

I think it's a conversion to a plug in hybrid. Less petrol, lots of electricity from coal powered stations...

[fifthcolumn]

I think it's a conversion to a plug in hybrid. Less petrol, lots of electricity from coal powered stations...

Ralph is right.

For those who don't know:
There is a difference between a plain vanilla "hybrid" and a "plug in" hybrid.

The plain hybrid is the one the poster described as getting all it's energy from petrol (and regenerative braking) and this charges up the battery.

The "plug in" hybrid is a modification of a plain hybrid where the battery can be charged up by plugging it in (to the coal powered mains, or solar panels or wind or whatever other form of electricity). The advantage of the plug in version is that it is a pathway to a non-fossil-fuel powered form of personal transport as well as reducing the amount of petrol that is burnt.

[clv101]

Okay, a plug-in can approximately double efficiency. I thought we were just talking about a battery swap out.

[fifthcolumn]

Okay, a plug-in can approximately double efficiency. I thought we were just talking about a battery swap out.

A plug-in can do more than double efficiency.
A prius with an appropriate plug in battery pack can get 160mpg which is well over double the standard prius's 48 mpg.

A ford escape (SUV) plug-in can get over 100 mpg.

In any event, plug-ins are only the mid-term solution to getting rid of fossil fuel powered personal transport altogether. For those that will be able to afford cars in the future they're likely to be all-electric.

If there is no economic collapse I see plug-ins as a bridge till batteries are cheap enough to mass produce something like the Th!nk city car at a price everyone can afford.

[goslow]

I agree with many points here:

For sure electric cars will generally be more efficient than the cars we have now.

Cycling is not so easy in hilly areas, but if you can cycle or walk, its a great idea!

I am trying to get our kids used to walking into town, they can manage about 1-2 miles at the moment. They also love their scooters and that allows us to get places more quickly on foot.

I expect the requirement for journeys by car will reduce as we forced to re-localise our work and community activities PPO. And more deliveries of goods to houses instead of individual shopping trips. And more use of shared/public transport rather than individuals all going to work/church/school etc in their own cars. Even in the countryside, things will change.

I would hope that the disabled, aged etc will be able to get lifts with friends with cycle operated rickshaws!

[sentiententity]

A plug-in can do more than double efficiency.
A prius with an appropriate plug in battery pack can get 160mpg which is well over double the standard prius's 48 mpg

Ah...this makes more sense. Although we can't calculate efficiency ([Energy in/Energy out]x100%) until we know how much the car got out of the mains when the battery was charged, we do know that we are probably not more than doubling it. What we are (hopefully) doing is reducing the emissions per mile as the car relies more on its battery for the journey. These will vary, depending on whether it is charged from a wind turbine in the back garden or a non-CCS coal-fired power station, or whatever in between.

s.

[fifthcolumn]

Ah...this makes more sense. Although we can't calculate efficiency ([Energy in/Energy out]x100%) until we know how much the car got out of the mains when the battery was charged, we do know that we are probably not more than doubling it.

How?

For someone who didn't even know what a plug-in was before it was explained to you (in brief) you are able to pull efficiency numbers out of the air?

I think not.

I won't just accept somebody's breezy statement as truth without verification.

Personally I have done a great deal of research into this and if someone can't be bothered to go read before offering their opinion I consider them not to have a right to even open their mouth.

Try googling "well to wheel" and get back to us with your recalculated efficiency numbers before offering an ill-thought through opinion again.

[PS_RalphW]

Try googling "well to wheel" and get back to us with your recalculated efficiency numbers before offering an ill-thought through opinion again.

Personally I thought it a well thought out, pertinent and humble comment.

Efficiency is very hard to define when comparing electric and liquid fuel vehicles. Given the relative efficiencies of initial generation, transmission and storage of the electricity, against the efficiency of the ICE. Also the relative embedded energies in the two systems, and what it is we are measuring - toxic emissions, CO2, or theoretical percentage of source energy that gets translated into useful work.

Generally speaking, the argument is hard to resolve between a pure electric car and an ICE car. If you consider a hybrid car as an electric car with a large, heavy ICE thrown in, it is likely to be less 'efficient' by any normal method when compared directly with a pure electric vehicle. What you gain is the option to use the ICE to give extra range. Improved utility, but not necessarily improved efficiency.

[fifthcolumn]

Personally I thought it a well thought out, pertinent and humble comment.

I'm sorry to hear that Ralph.

Efficiency is very hard to define when comparing electric and liquid fuel vehicles.

If it's hard for you to figure out then do the research instead.
Other people have already figured it out.

Offering opinions when you don't know and are unable to figure it out because "it's hard" just muddy the water.

In my opinion this is exactly the problem we have in this country.
Everybody has an opinion including those who have no knowledge.
How are the decision makers going to be able to tell the difference between them?

It's exasperating.

[sentiententity]

Me: Ah...this makes more sense. Although we can't calculate efficiency ([Energy in/Energy out]x100%) until we know how much the car got out of the mains when the battery was charged, we do know that we are probably not more than doubling it.

Fifthcolumn: How?

For someone who didn't even know what a plug-in was before it was explained to you (in brief) you are able to pull efficiency numbers out of the air?

What is this, Reading Comprehension Problems day on Powerswitch or something?

If you read my post (the bit that you quoted, no less), you'll see that pulling an efficiency number out of the air is exactly what I didn't do. What I did was realise that these high fuel efficiency numbers people are coming out with (for a plug-in hybrid) are wrong, because people are not counting the electrical energy obtained from the grid when they calculate mpg, so they end up with an unrealistic number of miles travelled on one gallon. They weren't travelled on one gallon: they were travelled on one gallon plus an unknown but large amount of energy obtained from the grid before setting off.

To increase true mpg would require improving the efficiency of the vehicle as I mentioned in my last post (i.e. convert more of the energy in the fuel into kinetic energy in the car). If input remains the same (one gallon of petrol), then efficiency must rise for output (miles travelled) to rise. This is achieved by improving the efficiency of the engine, changing the bodywork to reduce weight or improve aerodynamics, etc, which is not what is being done here.

Everybody has an opinion including those who have no knowledge.

There's no need to be snotty.

It's exasperating

We agree here.

s.

[fifthcolumn]

If you read my post (the bit that you quoted, no less), you'll see that pulling an efficiency number out of the air is exactly what I didn't do.

So the following aren't your words then:

Although we can't calculate efficiency ([Energy in/Energy out]x100%) until we know how much the car got out of the mains when the battery was charged, we do know that we are probably not more than doubling it.

What I did was realise that these high fuel efficiency numbers people are coming out with (for a plug-in hybrid) are wrong, because people are not counting the electrical energy obtained from the grid when they calculate mpg, so they end up with an unrealistic number of miles travelled on one gallon. They weren't travelled on one gallon: they were travelled on one gallon plus an unknown but large amount of energy obtained from the grid before setting off.

Woolly thinking.
They DO only use one gallon.
That part of the energy to move the vehicle comes from elsewhere doesn't increase the number of gallons used.

To increase true mpg would require improving the efficiency of the vehicle as I mentioned in my last post (i.e. convert more of the energy in the fuel into kinetic energy in the car).

What is "true mpg"? It means what it says it means "miles per gallon".
This is the same stupid confusion that occurs over on the oildrum about EROEI.

If input remains the same (one gallon of petrol), then efficiency must rise for output (miles travelled) to rise. This is achieved by improving the efficiency of the engine, changing the bodywork to reduce weight or improve aerodynamics, etc, which is not what is being done here.

No. You don't understand what's happening here and are confusing the whole thing. Which is exactly the problem.
1. There STILL is only one gallon of petrol going in.
2. An electric engine is more efficient than an ICE for the non-petrol part.

There's no need to be snotty.

On the contrary. Decision makers read this site. If woolly thinking people are encouraged to share their opinions, decion makers might come away ill-informed and bad decisions will be made which will ultimately affect all of us.

If you want to claim you are informed: go ahead and do the google "well to wheels". Don't let your pride get in the way just because I am snotty with you.

[JohnB]

My 77 year old neighbour only has one leg, so cycling 2.7 miles to church is possibly not an option, whereas an automatic Smart car is.

If neighbours with one leg, and other people who were unable to walk or cycle 2.7 miles, were the only ones who drove cars, it wouldn't matter if their cars did 20mpg. It's the fact that there are millions of cars, consuming vast amounts of fuel and causing huge amount of emissions, that's the problem.

The words pot, kettle and black spring to mind, as I've just driven my van to the supermarket, but it was 6 miles each way .

[Dan McNeil]

Poor old senile-entity. cvl101 too. The article on that Prius that I posted a link to clearly stated in about line 3 that it was a plug-hybrid. I mean, duhhhhh, read the link before tap tapping away. Now the self-styled econut is still digging away and getting confused about MPG.