Why an electric motor is used in hybrid cars

[JimiJams]

I've been wondering about hybrid car technology lately and I'll start with just the most basic question to try and gain some clarity. I'll ask more specific questions if they come to mind after someone explains this first question. So, I was wondering why an electric motor is used in hybrid cars if it's just being charged by an IC engine anyway. Why not just use that small IC engine alone to power the car and eliminate the electric motor?

 

[berkeman]

I've been wondering about hybrid car technology lately and I'll start with just the most basic question to try and gain some clarity. I'll ask more specific questions if they come to mind after someone explains this first question. So, I was wondering why an electric motor is used in hybrid cars if it's just being charged by an IC engine anyway. Why not just use that small IC engine alone to power the car and eliminate the electric motor?

One reason is regenerative braking. What can you tell us about how that works, and why it is an improvement?

 

[JimiJams]

So, is regenerative braking one of the main reasons? Correct me if I'm wrong , but the bulk of great fuel economy can be attributed to the really small combustion engine, right?

I'm no mechanical engineer (preparing to study EE), but from what I read briefly today, regenerative braking is thermal energy captured from the brakes by the electric engine and stored back in the batteries.

Does regenerative braking really contribute much to energy and fuel economy? And are there any other reasons why the electric engine is used instead of a small IC engine alone?

 

[berkeman]

So, is regenerative braking one of the main reasons? Correct me if I'm wrong , but the bulk of great fuel economy can be attributed to the really small combustion engine, right?

I'm no mechanical engineer (preparing to study EE), but from what I read briefly today, regenerative braking is thermal energy captured from the brakes by the electric engine and stored back in the batteries.

Does regenerative braking really contribute much to energy and fuel economy? And are there any other reasons why the electric engine is used instead of a small IC engine alone?

Wikipedia lists 3 main reasons that hybrid electric vehicles are more efficient...

http://en.wikipedia.org/wiki/Hybrid_car#Environmental_issues

.

 

[JimiJams]

It seems to me that most of the energy used by the electric motor comes from the combustion engine, though. So is the electric motor just responsible for regenerative braking and extra power when it's needed? The combustion engine seems like it's being used the most in a hybrid car, which means most of the lower emissions and fuel economy can be attributed to just a small IC engine.

 

[SteamKing]

Shhh. You're asking too many questions. Next, you'll be wondering if hybrids are cost effective in terms of fuel savings v. price differential for a hybrid over a regular power train.

 

[russ_watters]

A couple not mentioned:
Electric motors are efficient over a much broader range of power outputs than ICE's.
Electric motors start faster and therefore can be shut off when not in use.

These two factors are a lot of the reason ice cars are so inefficient at city driving but hybrids are efficient.

[Edit]Would be nice to see an accounting of the energy benefit to f each feature.

 

[JimiJams]

I think I understand the role of the two motors now. The small combustion engine can charge the batteries much more efficiently than it can run the car because of the different work loads. Then the electric motor can be used to run the car off the energy stored in the batteries because it operates more efficiently than the IC engine. I can see the whole picture now, thanks for the clarity guys!

 

[OmCheeto]

..., I was wondering why an electric motor is used in hybrid cars if it's just being charged by an IC engine anyway.

This article may be almost 2 years old, but I think it somewhat answers your question:

http://www.engadget.com/2011/11/19/jay-lenos-chevy-volt-still-has-original-tank-of-gas-11-000-mil/

The Chevy Volt is a hybrid. Leno drove it over 11,000 miles, without refilling his gas tank, implying that his electric motor was almost never charged by his IC engine.

Electric motors can be plugged in when you get home. They can also be plugged in when you get to work. They can also be plugged in when you get to the store. If none of the previous three sentences are true where you live, then you don't live where I do.

Why not just use that small IC engine alone to power the car and eliminate the electric motor?

IC engines are at the most, 25% efficient, and in the real world, less than 5% efficient. (Based on my research of the data available from the Carnegie Melon Univ. "Charge Car" program.)
E-engines don't suffer from this inefficiency.
and E-engines, although minuscule, can deliver neck breaking acceleration.

https://www.youtube.com/watch?v=GDHJNG2PngQ

I once saw the Killacycle in real life. I got whiplash*, just from watching it.

----------------------------
*Ok, slight exaggeration... It just seemed like a neck snapping event. But wow.

 

[russ_watters]

Wow, really? An electric car doesn't use gas? That's profound! Plug-in hybrids - and in particular that article - make the efficiency situation cloudier, not clearer because you typically aren't even told how much energy is being used in them and from what source (or are only told the gas and the electricity is treated like it magically appears in the car, from an eternal fountain!), much less how it is being used!

IC engines are at the most, 25% efficient, and in the real world, less than 5% efficient. (Based on my research of the data available from the Carnegie Melon Univ. "Charge Car" program.)

I'd like to see where exactly you got that, because it really doesn't compute. It doesn't even actually make any sense: they can't be both at the same time. 25% sounds about right for real-world efficiency of a car engine on a highway. And city driving varies widely of course, but as rated tends to be something like 2/3 what the highway efficiency is.

And in any case, if an article on the issue makes no comparison with electric motor driven efficiency, it is completely useless anyway! What is the energy use/cost difference between the two? Hypothetically, if the energy comes from gas (oil) either way, how much less oil does an electric car actually use? These aren't questions that can be handwaved away with the utterly pointless statement that an electric car doesn't use gas.

Here's an article that actually discusses the issue. And shares my sarcastic exasperation about the pointless, hand-wavey, worshipey treatment the issue typically gets: http://www.motortrend.com/features/consumer/1010_chevy_volt_the_real_efficiency_number/viewall.html

Here's what it says about the volt:

So during its 40 or so miles of EV operation, the Volt's rate of energy use is around 0.32 kW-hr/mile (32.0 kW-hr/100 miles if you don't like fractions) or 105 miles per equivalent gallon of gas.

Then they go on to derate the Volt's number a little more due to the charging inefficiency that isn't picked up in those numbers:

So while we're saying that our Volt returned 126.7 mpg over its 299 mile run here, when you account for it electrical consumption, the total number drops to 72.9 miles per combined gallons. Still pretty good - though a normal Prius can get 50 mpg.

That's actually surprisingly poor to me. Since a car engine is at best about 25% efficient, I would have expected an electric to be at least 3x the efficiency, so if under gas power it is a 40mpg car, I would have expected at least 120mpg equivalent electrical operation. And remember, that electricity comes from a power plant which if it runs on fuel is probably only 40% efficient anyway. Now that 73mpg is more like 30mpg! It means a plug-in hybrid or electric isn't really any more energy efficient than typical gas driven car, much less a gas hybrid!

In terms of cost:

At a typical price of $0.12 per kW-hr (quoting the EPA), the Volt's cost per mile whilst EVing is about 3.8 cents. By comparison, in its gas-burning mode -- assuming 40 mpg and a national average of $2.80 per gallon -- you're looking at 7 cents per mile.

Old numbers and both are low, so the ratio is probably about the same. As an electric, it costs half as much as as a strictly gas powered car.

So if there is no actual energy benefit, why would there be a cost benefit? The fossil (and other) fuels used in generating electricity (coal and natural gas, 35% of our power each) are much cheaper than gasoline, that's why!

For example, what if we just used the natural gas in a car?

In the Civic CNG’s favor is the ridiculously low price of its fuel. The national average for CNG in January 2012 (the most recent month of the EPA’s regular reports) was $2.13 per equivalent gasoline gallon. In EPA highway figures and using the most recent national average price of $3.52 per gallon for regular gasoline, the Civic LX and hybrid cost 9.0 and 8.0 cents per mile compared with just 5.6 cents per mile for the CNG.

http://www.caranddriver.com/reviews/2012-honda-civic-natural-gas-test-review

1.4:1, so not as good as the 2:1 for electricity, but I suspect that is because of the low penetration of CNG results in a huge mark-up. That cost quoted is much, much higher than the low pressure natural gas people burn in their homes/businesses: more than 50% higher for the home retail price alone and that's even higher than the commercial price.

But even at that, a natural gas hybrid (instead of natural gas ICE alone) would necessarily make up all of the rest of that difference, being as cheap and efficient to operate as an electric. Good news because it means in the short term, while natural gas is plentiful, we never really have to suffer the limitations of full electrics. Natural gas hybrids will provide exactly the same energy performance without the limitations.

 

[AlephZero]

Electric motors start faster and therefore can be shut off when not in use.

That isn't new technology, for IC engines. There have been IC engine cars marketed in Europe with engine shut off for 30 years or more. The interest has increased in the last decade. In 2011 Bosch (the auto components and subsystems supplier) forecast that 50% of new Europoean car sales would have the technology by 2013 (but I don't know how that forecast turned out).

It integrate nicely with manual transmissions as the "default" in Europe. The engine stops when the transmission is in neutral and the clutch pedal is up, and restarts when you press the clutch. The extra fuel cost of a "hot start" is claimed to be less than 1 second of fuel consumption at idle.

The modern systems are smarter than the old ones - e.g. they system disables itself if the battery charge is low, since obviously the electrical load of lights, aircon, etc is not being met from the alternator when the engine is off.

Future developments are "early engine stop" when the car is predicted to be slowing to a stop (possibly including sensors to detect other vehicles). and "auto coasting" to disengage and stop the engine at any speed where no power is being supplied to the drive train. IIRC Porsche are working on "auto coasting", which probably means it will soon filter down to VW and Audi.

Given the "baseline" fuel consumption for medium size diesel engined cars in real driving conditions is the EU is "60 mpg at 60 mph" these days, even without that technology hybrids aren't a no-brainer option.

 

[AlephZero]

It's interesting the way small gasoline engnes are developing these days. I recently had a courtesy car with a 1200cc engine. One of the "features" (on the cheapest model in the range) was a display of the recommended gear for best fuel consumption. It was a bit surprising to see such a small engine recommending the highest gear at only 1500 RPM (and speeds below 30 mph) but for town driving the performance was perfectly acceptable. I guess the engine management system was set up to run that way.

 

[russ_watters]

That isn't new technology, for IC engines. There have been IC engine cars marketed in Europe with engine shut off for 30 years or more. The interest has increased in the last decade. In 2011 Bosch (the auto components and subsystems supplier) forecast that 50% of new Europoean car sales would have the technology by 2013 (but I don't know how that forecast turned out).

It integrate nicely with manual transmissions as the "default" in Europe. The engine stops when the transmission is in neutral and the clutch pedal is up, and restarts when you press the clutch. The extra fuel cost of a "hot start" is claimed to be less than 1 second of fuel consumption at idle.

That's great: I was aware the technology existed (as does the ability to do it yourself, of course), but didn't realize it was so widely used in Europe. It is my understanding that there is virtually none of it in the US. Perhaps that explains the always perplexing to me higher fuel efficiency of European cars vs American cars (that and the smaller engines of course)?

Lots of cars have an "Eco" button now in the US. They should include that as an optional feature. It would do more good than the usual meaningless tactic of softening the gas pedal. For an automatic car, it would have to be based on brake pedal use.

Future developments are "early engine stop" when the car is predicted to be slowing to a stop (possibly including sensors to detect other vehicles). and "auto coasting" to disengage and stop the engine at any speed where no power is being supplied to the drive train.

I can't see how that would provide much benefit at all, since it is my understanding that a gas engine doesn't use any gas when coasting anyway. I suppose if you are coasting but not stopping it isn't slowing you down as much as coasting against the engine, but if you are coasting to a stop anyway, all it should do is wear out your brakes faster.

 

[OmCheeto]

Wow, really? An electric car doesn't use gas? That's profound!

Much has changed in the last 5 years

https://www.physicsforums.com/showpost.php?p=1776095&postcount=19

Plug-in hybrids - and in particular that article - make the efficiency situation cloudier, not clearer because you typically aren't even told how much energy is being used in them and from what source (or are only told the gas and the electricity is treated like it magically appears in the car, from an eternal fountain!), much less how it is being used! I'd like to see where exactly you got that, because it really doesn't compute.

It does to me. Or did. I re-ran the numbers just now on my commute, from the numbers at CMU, and the efficiency was nearly 23.62%. I was almost ready to concede that you were correct.

But as I recall, they had a maximum regen number. I'm pretty sure I ran all the numbers myself, and determined, that if I could ixnay their regen numbers, I could invalidate my current foible.

It doesn't even actually make any sense: they can't be both at the same time. 25% sounds about right for real-world efficiency of a car engine on a highway.

It is, absolutely.

And city driving varies widely of course, but as rated tends to be something like 2/3 what the highway efficiency is.

And that's where everything falls apart.

And in any case, if an article on the issue makes no comparison with electric motor driven efficiency, it is completely useless anyway! What is the energy use/cost difference between the two? Hypothetically, if the energy comes from gas (oil) either way, how much less oil does an electric car actually use? These aren't questions that can be handwaved away with the utterly pointless statement that an electric car doesn't use gas.

Here's an article that actually discusses the issue. And shares my sarcastic exasperation about the pointless, hand-wavey, worshipey treatment ...

I'll try and find my non-hand wavy numbers. They are on my old laptop.

She still has some battery power left in her. And if not, I have another i-charger.

 

[xxChrisxx]

You boys have to be careful here. As this:

That's actually surprisingly poor to me. Since a car engine is at best about 25% efficient, I would have expected an electric to be at least 3x the efficiency, so if under gas power it is a 40mpg car, I would have expected at least 120mpg equivalent electrical operation. And remember, that electricity comes from a power plant which if it runs on fuel is probably only 40% efficient anyway. Now that 73mpg is more like 30mpg! It means a plug-in hybrid or electric isn't really any more energy efficient than typical gas driven car, much less a gas hybrid!

Is 'dodgy' use of numbers, especially the bold bit. As you've now taken MPG and MPGe which are comparable, as they are tank-to-wheel numbers (inc. charging loss which is acceptable to include). Then applied a factor that is then taking into account upstream efficiency on the EV but not on the conventional fuel.

You've also got to be to be very careful about where you getting figures from. Strictly speaking you can't compare 'real world' driving, as it doesn't provide a comparable test. As flawed as drive cycles are, they do provide a direct comparison between.

As an example, if you are real world test of an EV and ICE in stop start town driving. You are playing to the strengths of the emotor. If you go on a long steady cuise you are playing to the strengths of a combustion engine.

So all we can safely conclude is: it is difficult to conclude anything just from a numbers excercise.

 

[OmCheeto]

That's great: I was aware the technology existed (as does the ability to do it yourself, of course),

I would highly recommend that everyone ignore this comment.
As one of my hero's says; "We blow things up, so you don't have to."

I performed this experiment on my last vehicle, where if I thought I was going to be sitting for at least 20 seconds, I shut off my engine. My starter lasted a week. It may have been a coincidence, but I don't think so. Starters on regular vehicles are simply not designed to start your engine every 5 minutes. Of course, if you doubt me, you are welcome to do the experiment yourself. My starter wasn't really that difficult to replace. And we can always use more data points. And just as a reference, the Charge Car data of my trip to work indicates that I stopped 20 times over the 10 mile distance.

It may have been Charge Car's analysis of the cost of my commute where I came up with my numbers yesterday. That was back in November of 2009, so my memory is a bit fuzzy.

Compute Cost of Trip:

Estimated miles per gallon of this vehicle: 30 mpg
Price of gas: $4/gallon
Price of electricity: $0.11/kWh

With this car, this trip will cost: $1.35
With an electric car, this trip will cost: $0.26
By using an electric car, you save: $1.09, a savings of 81%!

Of course, it's all theoretical.

One thing I find funny is to what extent some people will go to, to prove that electric vehicles are not a viable alternative. Charge Car requested people upload, from their GPS devices, the data from their trips to and from work. Check out this persons daily commute:

Trip Statistics:

Total Distance: 959.88 miles
Trip Duration: 20 hrs 28 mins 54 secs
Time Idle: 2 hrs 28 mins 35 secs
Net Elevation Change: 4.69 feet
Average Speed: 35.96 mph
Max Speed: 81.31 mph

He doesn't need an EV, nor even an ICE. That dude need a nuclear reactor!
I'm curious what he does for a living(newspaper route for the entire state?), and how much a year he spends on amphetamines and coffee.


I've done other experiment that have gone wrong. I once over-pressurized my tires by about 10%, and one of them had what I would call a "dissociation" failure. It started bulging, which gave the car a somewhat Dr. Seuss kind of ride. It had to be replaced, and I didn't do that again, either.

... I can't see how that would provide much benefit at all, since it is my understanding that a gas engine doesn't use any gas when coasting anyway. ...

I'll interpret this as; "It was after midnight and my brain wasn't working right."

Unless you turn a gas engine off, it is using gas.

Didn't you say a while back that you'd purchased one of those fancy aftermarket fuel consumption gauges? Does it read out in gallons per hour? Or liters per minute. I really need to get one of those.

 

[xxChrisxx]

Unless you turn a gas engine off, it is using gas.

Injected engines don't fuel on overrun. The advantage of stopping an engine and coasting (ie disconnecting it from the drivetrain) is that you don't have pumping losses.

It's the next step to 'stop start', the car acutally coasts with the engine fully off. Though with EPAS and vacuum storage and other electric driver aids you don't lose steering or assisted brakes. Which is nice.

 

[OmCheeto]

You boys have to be careful here. As this:



Is 'dodgy' use of numbers, especially the bold bit. As you've now taken MPG and MPGe which are comparable, as they are tank-to-wheel numbers (inc. charging loss which is acceptable to include). Then applied a factor that is then taking into account upstream efficiency on the EV but not on the conventional fuel.

You've also got to be to be very careful about where you getting figures from. Strictly speaking you can't compare 'real world' driving, as it doesn't provide a comparable test. As flawed as drive cycles are, they do provide a direct comparison between.

As an example, if you are real world test of an EV and ICE in stop start town driving. You are playing to the strengths of the emotor. If you go on a long steady cuise you are playing to the strengths of a combustion engine.

So all we can safely conclude is: it is difficult to conclude anything just from a numbers excercise.

I pretty much agree with everything, except your last comment.

This will probably be the 10th time I've quoted this guy's lecture:

The US imported $430,000,000,000 worth of oil last year.

Now, I'm not sure where he got that number, as he was only the energy secretary.

But taking that number, the number of gallons consumed(~4) by Jay Leno driving 11,000 miles, the cost of solar panels(~$1/watt woo hoo!)... Well, you do the math. People keep whining about how taxes are too high. I say BS. Taxes get recycled in this country. That $430 billion(every freakin' year!) does not. It's money down the drain, or out the tailpipe, whatever.

The sooner people figure out that getting 200 mpge is kinda cool, the better.

-----------------------
ps. 386 dtg, and the Koch brothers, OPEC, Exxon, etc., will be out to kill me...

 

[OmCheeto]

...

I'll interpret this as; "It was after midnight and my brain wasn't working right."

Unless you turn a gas engine off, it is using gas.

...

Injected engines don't fuel on overrun. The advantage of stopping an engine and coasting (ie disconnecting it from the drivetrain) is that you don't have pumping losses.

It's the next step to 'stop start', the car acutally coasts with the engine fully off. Though with EPAS and vacuum storage and other electric driver aids you don't lose steering or assisted brakes. Which is nice.

Apparently it was my brain that wasn't working right.
Such things (DFCO = Deceleration Fuel Cut Off) do exist.

In their quest for fuel efficiency, automakers look to every part of the drive cycle to determine where they can make gains. A recent innovation is shutting off the fuel flow to the cylinder when the car is decelerating. Cars traditionally have gone to idle speed when you take your foot off the gas, still feeding fuel to the cylinders to keep the engine turning. But if the car is moving at sufficient speed, its own momentum can keep the engine turning.

I'll blame my ignorance on being old. I didn't have that on my 61 beetle, and if I shut the engine off while driving, it did all sorts of weird things.

This technology must require some healthy automation. With the foot off the accelerator, the system would shut off the fuel, but this would create significant braking, so the system would have to open the butterfly valves, but that would reduce the vacuum available to the power brakes, making it a bit more dangerous. Ah! Sometimes technology scares me.

hmmm... I wonder...

By Ralph Vartabedian and Ken Bensinger
October 18, 2009
The 2009 Lexus ES 350 shot through suburban San Diego like a runaway missile, weaving at 120 miles an hour through rush hour freeway traffic as flames flashed from under the car.

At the wheel, veteran California Highway Patrol Officer Mark Saylor desperately tried to control the 272-horsepower engine that was roaring at full throttle as his wife, teenage daughter and brother-in-law were gripped by fear.

"We’re in trouble. . . . There’s no brakes,"

272 hp? That's more than my truck, two gliders*, and all my outboards put together.

On one website I visited, someone mentioned that DFCO was more an emissions thing than a fuel saving thing.

Anyways, thank you everyone for educating me.

*glider is an EV enthusiast term for a car that doesn't have a working ICE.

 

[SteamKing]

I pretty much agree with everything, except your last comment.

This will probably be the 10th time I've quoted this guy's lecture:



Now, I'm not sure where he got that number, as he was only the energy secretary.

But taking that number, the number of gallons consumed(~4) by Jay Leno driving 11,000 miles, the cost of solar panels(~$1/watt woo hoo!)... Well, you do the math. People keep whining about how taxes are too high. I say BS. Taxes get recycled in this country. That $430 billion(every freakin' year!) does not. It's money down the drain, or out the tailpipe, whatever.

The sooner people figure out that getting 200 mpge is kinda cool, the better.

-----------------------
ps. 386 dtg, and the Koch brothers, OPEC, Exxon, etc., will be out to kill me...

Not all of the crude imported into the U.S. is turned into gasoline has everyone forgotten diesel and aviation fuel?). There are a myriad of other uses for crude besides fuel production. Even if 100% of the passenger cars in the U.S. were totally electric, this would not negate the need to fuel whatever was generating the electricity. Everyone talks about using solar and wind, but very few are willing to have these types of electricity generators sitting in their backyards. A lot of people naively think that electricity is obtained by plugging whatever into the closest available outlet, blissfully unaware of the source of this power, because the generating plant may not even be within the same city or state in which they reside.

 

[OmCheeto]

Not all of the crude imported into the U.S. is turned into gasoline has everyone forgotten diesel and aviation fuel?).

That is actually one of my goals. To have all oil used where it makes sense: Aviation, long distance trucking, that guy from Salem.

There are a myriad of other uses for crude besides fuel production. Even if 100% of the passenger cars in the U.S. were totally electric, this would not negate the need to fuel whatever was generating the electricity.

Solar manufacturing companies are dropping like flys. The precipitous drop in solar panel prices is a most wonderful byproduct.

Everyone talks about using solar and wind, but very few are willing to have these types of electricity generators sitting in their backyards.

Odd you should mention that. My two neighbors and I have been discussing the collective removal of 25+ >100 foot tall Douglas Fir trees that grow on our properties. I will be the happiest of course, as all of these trees yield me about 1 effective hour of sunlight during the winter months.

Hence my aversion to investing in more solar panels. But 4 of the trees are on my property, and would make excellent wind turbine generator stands. And I would finally be able to permanently install solar panels on my roof.

But I'm a geek nerd solar scientist all the way, and use what I have for all manner of experiment:

Emergency replacement of my alternator that fell off one day:

150 watts. It worked! Yippie!

Solar boat experiment:

It worked! But I burned my hand on the motor. But the water temperature was 42'F, so I just soaked it for half an hour. Not even a blister. Yippie!

Although not my creation, this vehicle was inspired by something I hobbled together a few years earlier:
Cal's solar powered, remote controlled, volleyball court watering device:

It's current incarnation has tank tracks.
Cal is now more popular than I am at the beach.
He had a gas powered version many years ago. I never saw it.
I've been trying to help him with the water pumping portion of the system, as when I saw it, I understood why it didn't work 1/10 as well as mine, even though he had spent 10 times as much as I had on pumps and batteries and pipes. He claimed; "I'm just a retired truck driver. What the hell do I know about this stuff."

Understanding the physics behind things is really important.

A lot of people naively think that electricity is obtained by plugging whatever into the closest available outlet, blissfully unaware of the source of this power, because the generating plant may not even be within the same city or state in which they reside.

I know where mine comes from. I opted for a wind farm green option on my electric bill, well over 15 years ago. It's a bit more expensive, I think. But I don't care, as I can afford to leave the world a little greener for my GNN's^*.

I'm not sure why people want to project onto me their thoughts: "You're only doing this for your self interest!".

Um no. I do it because:
a. I love science
b. I love tinkering
c. I would rather die poor and leave the world a better place, than die rich and leave my GNN's a spoiled planet.

Though my plans are to die rich, and leave them a better place to live. But I can't discuss that, until after the patents are filed, of course.

---------------------------
*GNN's = grandnieces and grandnephews
It was getting messy.
I never had kids myself.

 

[SirAskalot]

OmCheeto: I would love to see more of your 'inventions', you haven't thought about opening your own thread posting pictures and descriptions of your projects? 'Industry secrets' can be withheld from the public, but general experiences and conclusions would be interesting to hear. I keep getting fascinated about the projects people have going on.

As for the future of hybrid vehicles, Volvo is thinking of using KERS (kinetic energy recovery system) as a option to battery storage. BMW is, as mentioned, producing cars with freewheel gearbox. This is in general not a new invention since a few cars back in the day had this function (with variable success).

 

[OmCheeto]

OmCheeto: I would love to see more of your 'inventions', you haven't thought about opening your own thread posting pictures and descriptions of your projects? 'Industry secrets' can be withheld from the public, but general experiences and conclusions would be interesting to hear. I keep getting fascinated about the projects people have going on.

As for the future of hybrid vehicles, Volvo is thinking of using KERS (kinetic energy recovery system) as a option to battery storage. BMW is, as mentioned, producing cars with freewheel gearbox. This is in general not a new invention since a few cars back in the day had this function (with variable success).

Ha! I have a webpage somewhere, with all of my failed attempts. I had to stop posting there of course, as, I started learning from this darned PF place, and eventually, solved some weird problems.

Along the way, I saw some beautiful images:

Circa 1920 Detroit Electric as seen in the rear view of a Tesla​

On a totally off topic, semi-on-topic, totally out of this world thought:

I wrote a short story in 2003, days after the invasion of Iraq.

Fearing another "War for Oil", as he termed it, President Powell funneled billions into photovoltaic technology companies. This, along with a $3/gallon gasoline tax, weaned America off of its foreign oil dependency within one year. Being able to travel for virtually nothing, the American people quickly amassed trillions of dollars in excess wealth. The rest of the world quickly followed America's lead.

It was, of course, a whimsical piece of fiction.

 

[OmCheeto]

OmCheeto: I would love to see more of your 'inventions', you haven't thought about opening your own thread posting pictures and descriptions of your projects? 'Industry secrets' can be withheld from the public, but general experiences and conclusions would be interesting to hear. I keep getting fascinated about the projects people have going on.

I put together an electric lawn mower this last Thursday.

Some might wonder what this has to do with the original OP. Well, it's kind of the point I've been trying to make. It doesn't make sense for that guy who drives 900+ miles on his daily commute to have an electric vehicle. Nor does it make sense for me to have a gas powered mower. I have a 100 foot long extension cord.

It did though take me until yesterday to get the mower to work. I apparently did not fully comprehend the physics of tall grass. And after breaking six sets of locking devices to keep the mower blade attached to the motor shaft, I got a little impatient and over-engineered the hell out of it. And now the lawn is mowed. And I never have to buy gas for it again. The motor is a 110vac model. I would have preferred using the 12vdc motor from my e-boat experiment, but I think I may have toasted it. I am apparently the epitome of some old guy's quote:

I have not failed. I've just found 10,000 ways that won't work.

As for the future of hybrid vehicles, Volvo is thinking of using KERS (kinetic energy recovery system) as a option to battery storage. BMW is, as mentioned, producing cars with freewheel gearbox. This is in general not a new invention since a few cars back in the day had this function (with variable success).

KERS and other ideas are covered in one of my favorite threads: You! Fix the energy crisis!

I don't see that we discussed the freewheel gearbox. My Chia Saab has one, as did my brothers 1959 Ford Pickup.

 

[DrClaude]

Not all hybrid cars have the wheels running only on electric motors:

http://www.volvocars.com/intl/campaigns/hybrid/pages/v60-plugin-hybrid.aspx

 

[OmCheeto]

Not all hybrid cars have the wheels running only on electric motors:

http://www.volvocars.com/intl/campaigns/hybrid/pages/v60-plugin-hybrid.aspx

Zounds like zee Volt tsu meer.

 

[mheslep]

...And remember, that electricity comes from a power plant which if it runs on fuel is probably only 40% efficient anyway.

If your calculation continues upstream from the tank (battery) back to the well (power station), then it should be done on both sides. An actual gallon of gas has to be transported and refined (10-20% energy overhead).

 

[OmCheeto]

...

I'll try and find my non-hand wavy numbers.

...

I'm still recovering from my birth week...

1/2 mv^2 & mgh, are all that I can comprehend...

 

[Jupiter6]

OmCheeto, I enjoy looking at your experiments but the pessimist in me is not sure solar cells will help us save money.

Right now, you get a tax credit and a 15? year break even point? Eventually when everyone gets solar panels and energy companies start making solar panel fields and filling the oceans with solar panel barges, someone somewhere will do a study and conclude that not enough radiant heat is hitting the Earth and too much convective waste heat is being dumped by solar powered devices. Plant and sea life will suffer and the air temperatures will rise.

Under the guise of environmentalism, some energy companies will lobby politicians to impose taxes on private ownerships of: all new solar cells, square footage occupied by solar panels and kw-hrs generated by solar cells.

Or am I just being paranoid

I've always thought the solar collector/steam generators in the southwest were a great idea.

 

[OmCheeto]

OmCheeto, I enjoy looking at your experiments but the pessimist in me is not sure solar cells will help us save money. ...

I read the other day, that Feynman was inspired by his father. His father, IMHO, was correct:

What makes it go? Everything goes because the sun is shining.

No, the toy goes because the spring is wound up.

How did the spring get wound up?

I wound it up.

And how did you get moving?

From eating.

And food grows only because the sun is shining. So it's because the sun is shining that all these things are moving.

At which point, many years later, whilst recalling this, he would say;

That would get the concept across that motion is simply the transformation of the sun's power.

And then, some odd years later, you state;

Or am I just being paranoid
Right now, you get a tax credit and a 15? ...

I became a bit upset with someone, the other day, because they were projecting upon me, that I, should worry about money.

Taxes... Schmaxes...

I've always thought the solar collector/steam generators in the southwest were a great idea.

As do I.

But, we are of course, way off topic: why an electric motor is used in hybrid cars

To which I can only respond; "Because it makes sense".

 

[russ_watters]

I know I'm late, but...

As you've now taken MPG and MPGe which are comparable, as they are tank-to-wheel numbers (inc. charging loss which is acceptable to include). Then applied a factor that is then taking into account upstream efficiency on the EV but not on the conventional fuel.

Don't the upstream efficiency numbers of the EV exclude the same mining and refinement that the conventional fuel do? In other words, isn't the natural gas used in a gas turbine identical to what powers your stove? And isn't the fuel oil used in a power plant similar in its refinement to what is used in a car?

You've also got to be to be very careful about where you getting figures from.

So all we can safely conclude is: it is difficult to conclude anything just from a numbers excercise.

Understood, which is why for my purposes I tracked my fuel economy with a spreadsheet and made calculations based on my driving patterns to help decide if (not) I should by a hybrid or a regular gas car.

 

[russ_watters]

I would highly recommend that everyone ignore this comment.
As one of my hero's says; "We blow things up, so you don't have to."

I performed this experiment on my last vehicle, where if I thought I was going to be sitting for at least 20 seconds, I shut off my engine. My starter lasted a week. It may have been a coincidence, but I don't think so. Starters on regular vehicles are simply not designed to start your engine every 5 minutes.

Well, it isn't like I have the persistence to do this on a regular basis anyway, so I'm sure I'll be fine.

Unless you turn a gas engine off, it is using gas.

Didn't you say a while back that you'd purchased one of those fancy aftermarket fuel consumption gauges? Does it read out in gallons per hour? Or liters per minute. I really need to get one of those.

Yes, I have and it does. Once warmed-up, the engine does not use gas when coasting. Which therefore also means the fuel economy increases markedly when the engine is warm.

At idle, it uses about 0.5 gal/hr which if the car runs at 30mpg highway is 1/4 of highway fuel consumption at 60mph. That's an awful lot of gas wasted idling!

 

[russ_watters]

If your calculation continues upstream from the tank (battery) back to the well (power station), then it should be done on both sides. An actual gallon of gas has to be transported and refined (10-20% energy overhead).

As I asked-of Chris, doesn't a gallon of oil used to generate electricity also need similar refining and transporting?

 

[mheslep]

As I asked-of Chris, doesn't a gallon of oil used to generate electricity also need similar refining and transporting?

Sure, but then oil fired electric generation is less than 1% of US generation and falling. By contrast no refining step is required for natural gas.

 

[SteamKing]

When oil-fired generating plants were in operation, the fuel did not need to be highly refined like the motor fuels used in cars and trucks (i.e., gasoline and diesel). In fact, the residual fraction from the refinery (what was left after the gasoline and diesel was produced) was used for firing generating plants and for large ships which used heavy fuel oil for large steam or slow speed diesel propulsion plants. To be sure, the residual fraction was not used solely for fuel, but it was a by-product of the refining process.