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But if the engine's temperature is too low, such as when it's being started or being operated under very low loads, the mixture doesn't get hot enough to combust. And at high loads, when the temperature is high, the mixture can combust too early, out of sync with the cycling of the engine, causing a potentially damaging phenomenon called knock. Differences in fuels can also affect precisely when the mixture combusts.
The hybrid system switches between the two forms of combustion. To do this requires changing the way the engine deals with combusted gases. During spark combustion, the gases are forced out through an open valve. In HCCI, the timing of the opening of that valve is changed so that it closes before the gases completely escape, trapping them inside.
John Heywood, a professor of mechanical engineering at MIT who was not involved with this work, says that HCCI could eventually provide even greater benefits as researchers find ways to adapt the engine so that they can use it for a wider range of loads. What's more, it could be used in combination with other gas-saving technologies already available on many vehicles. The extent to which HCCI can be combined with other approaches could determine how widely it's adopted, suggests Heywood.
An engine from Lotus and Continental Powertrain consumes 15 percent less fuel.
A new engine design could significantly improve fuel efficiency for cars and SUVs, at a fraction of the cost of today's hybrid technology.
Electric Motors Still 3x Better
Typical electric vehicle motors still operate above the 90% efficiency mark, so I think that they will win in the end.
For a good comparison between an electric drive train and other types of drive trains for a given amount of energy input, take a look at this slideshow (click on "view presentation" button to bring up slides:
http://www.teslamotors.com/blog2/?p=25
Re: Electric Motors Still 3x Better
First let me state that I'm not a automotive engineer, just someone who finds the topic interesting.
Even though electrical is more efficient, you still have to generate that power. Until someone develops a battery pack that delivers 400 miles per charge and the cost is comparative to gas, it'll never find more than a toe hold in the market.
What I don't understand is why a smaller battery pack isn't put into a car (able to hold, say a charge to carry the car 20 miles) and then a ultra efficient engine is used to charge the battery. If many of the energy efficient concepts were used (say, HCCI and BMW's new 6 stroke concept that is due out in the next couple of years), I don't see why getting 60mpg OR MORE isn't possible out of a midsize car. The battery pack would be nothing but a buffer between the engine and the drivetrain, allowing the engine to operate within a narrow band for best efficiency. As best I know, no one's doing this so I suspect that I'm over simplifying the issue. So, what is it that I'm missing?
Re: Electric Motors Still 3x Better
The technology you refer to is what Toyota is pursuing with the "pluggable" hybrid. The battery pack has been substantially increased allowing the car to run about 10 miles before the gasoline engine kicks in. The plans are to increase the range substantially.
At night the car can be plugged into the home's house current to use the household electricity to drive the first 10 miles.
Re: Electric Motors Still 3x Better
well let us look at the electrical grid... some 50 percent efficient natural gas turbine sends 85 percent to the house where you charge your car...
Why not just use the natural gas engine with an HCCI design? ORNL is doing this research now and with diesel engines. We will wait for the battery that charges enough power to run the 18 wheelers for a long while.
Re: Electric Motors Still 3x Better
I would agree that electric cars need to be cheaper with comparable performance in terms of speed and acceleration, but I think the range is more of an perceived issue than a real one.
I know not everyone is like this, but I probably drive more than 200 miles in a single day 5 or 6 times a year, if that. I would be glad to have an electric car to drive during my normal commute + errands, etc., and then use our other car, or even rent another car, for longer trips. With no oil changes, no fill-ups (plug in at night though), no problems with mufflers, catalytic converters, or all of the other heat- and vibration-related wear on the vehicle, electric vehicles may be very easy to own and operate, and very desireable--even without a full tank of gas range.
I guess time will tell . . .
Re: Electric Motors Still 3x Better
Check out http://www.chevrolet.com/electriccar/
Due out by 2010 I think.
Re: Electric Motors Still 3x Better
If you are going for a shorter charge, why not just plug in a lot of high capacity capacitors? They wont wear out as quickly and are probably safer than using chemical batteries. I also suppose you could get higher discharge rate than what a given battery can provide.
Re: Electric Motors Still 3x Better
Ultracapacitors will truly change the game if they can be developed to deliver enough energy and power. For now I know that ultracap's are being used in some smaller, shorter-range EV's. TechReview did a story earlier this year on a company called EEStor, which is in this industry and has shown some promise in developing the technology.
Ultracaps could potentially endure millions of discharge cycles, and be recharged in seconds to minutes--more quickly and easily than filling up your tank.
http://en.wikipedia.org/wiki/EEstor
Re: Electric Motors Still 3x Better
Hey thanks for the link, I have always wondered what has been holding capacitors back, I guess the market has been focusing too much in other areas and just needed more of an impetus to go back to an old technology.
Guest (CarlHitchon)
Re: Electric Motors Still 3x Better
Most people drive less than 40 mile/day. E.g. I have a 30 mile round trip commute. A commuting car that gets 40 miles on a charge would do the trick for me. If you need a long range, you can use another vehical. If everyone with less than a 40 mile commute used electic, there would be a large savings. Central electric power generation is much more efficent that auto engines. Besides there are alternate ways to get that power.
Re: Electric Motors Still 3x Better
Unfortunately, there are 70% losses in generating electricity so electric motors are nice, but electric powered vehicles total energy consumption ends up being lower efficiency than gasoline / internal combusions engines.
Re: Electric Motors Still 3x Better
70% losses?, where did you get this piece of misinformation
Re: Electric Motors Still 3x Better
Older power plants have a 30% rate of converting the energy in the fuel to electricity (due to losses in the process). The newer plants are approching 40%.
Re: Electric Motors Still 3x Better
Yeah, I don't understand where your losses come in. Any clarification?
Re: Electric Motors Still 3x Better
Don't know where that 70% comes from, but remember that you also have to transport gasoline from refinery to gas tank. Not to mention refining the gasoline out of the crude oil. Not to mention shipping the crude from well to refinery. Not to mention the considerable costs of finding, drilling, running, and protecting the oil wells, most of which seem to be located in either inhospitable or politically unstable areas.
BUT!!! For whatever reason, electric vehicles are currently very expensive. The prices are downright shocking, so ordinary consumers are resistant to buying them. (Puns intended, but point is still valid.)
People can make efficiency comparisons 'til they're blue in the face, but in the end the only thing that matters is cost. A new Toyota Prius (hybrid) costs about $20K, while a new Honda Civic (nonhybrid) costs about $15K. Driving them around the city, people are reporting MPGs of 40 and 30. If you drive 10K mile/year (which is a lot, considering we're talking about mostly urban driving), then the Prius will use 250 gallons of gas, while the Civic will use 333. If gas averages $5/gallon over the next decade, that's a cost difference each year of $415. So it will take 12 years to make up the $5K initial cost difference of the vehicles. But if you take into account that the Civic buyer could put his $5K into long-term investments, plus pays less on car insurance, then the Prius owner NEVER catches up.
I invite you to make these kinds of TCO comparisons for all-electric vs. similarly-performing all-gas cars. I think you will be disheartened.
My advice to everybody is: Move close to work, if possible. Otherwise, car-pool. Also try to work four 10-hour days, if that's allowed. (Saves 20% on commuting costs, pollution, greenhouse gases, etc.)
Guest (gcrdyes)
Re: Electric Motors Still 3x Better
I love the holistic economic train of thought. People do not take into account the full spectrum of finance when determining what is "economical".
As former member of the military I have been in the middle east and it was not fun. So I applaud people buying expensive hybrids for environmental purposes. But what about 10 years from now? What is going to happen to the millions of pounds of batteries? With battery and ultracap technology evolving so quickly there is a chance that these batteries will not be recycled/refurbished.
In addition to living close to work, carpooling and telecommuting people should try biking as often as possible/practical. It would do more for America than just decrease our dependency on oil. Biking more often would help alleviate our burgeoning health crisis as well.
I do not know where you live at but there is a majority in this country(U.S.A.) that does not have the option to "move closer" to work and this alone would bring about an inimaginable set of circumstances. So what we would need would be 50 New Yorks or Mexico Cities in every state and then congestion charge taxes on vehicles like the UK. This would certainly solve the problem of commuting. How about if we just wind back the clock, and go back to the old horse and buggy. I like living in a rural area where crime is low, we don't have armed guards at the stores, and little peep holes to receive purchases through. We still pay for our fuel($2.499 and comparatively low considering national averages), after we pump.
We could just use technology to find a better solution.
I am certainly not an engineer but have been an automotive technician for years. I am still trying to figure out why, with current technology, the "brains" out there has not exploited forward motion technology to the fullest.
Are there any "brains" out there that can convince me that a self charging electric vehicle can not be designed or, if already designed(as I am sure it is), improved as to be practicle. We are working over time to improve the batteries or charge packs and capacitors for improved mileage per charge but not on the actual issue.
If a vehicle could be designed with a generator or generator pack(all 4 wheels) that would be geared for minimum drag, multi-stage charge, and be economically massed produced. There would be less need to super improve batteries, especially with the super capicitor theory. Then mileage per charge would be moot.
This, to me, would not be a monumental task for all the brains contemplating the greenhouse effects for the next 10 generations.
A generator for producing lights on a bicycle has been around for a long time. An electric engine at rest requires no power. Only lights at night, and creature comforts. When a vehicle is in motion I have full confidence that a system could be designed to exploit this motion to produce a charge.
At the very least this would deminish the need for super batteries and extend mpg of hybrids. Using the motion of the wheels, a ratio gearing system, and our current electronics technology, could not be that hard.
Oh! but getting past the battery companies would probably be like getting past the oil companies right?
An auxillery engine would then only be needed for those in hotter climates(the elderly or sick) requiring A/C. It would only need to run at idle, when the vehicle is not in motion or under high energy drain. This could improve mpg to 100 or much higher. With these "super capacitors", a second smaller electric motor, and also a secondary pully and switching system, the stored charge could be used to power an A/C at rest for a time.
Now, if this would not be practical in sort term urban driving it could certainly be advantageous on longer runs.
Now, add to this a coupling systen that could free wheel under no load situations, like a bicycle when going down hill, and the power consumption would be futher reduced and the charging capacity enhanced.
This is just off the top of my head, without study, but surely has merit, so any thoughts?
I wish I would have gone to MIT as I have other areas of interest where I see the need for improvement but lack the knowledge to invent.
Re: Coasting and Electric Motors Still 3x Better
We returned over the weekend from a long drive through the mountains of New Mexico and Colorado. I applied coasting to reduce consumption in our REV4 4-Wheel Drive 2007 Toyota. The REVA does 26 mile freeway and 18 city. I boosted the efficiency of the ride to 35 mpg through mountains and on the freeway to 33 mpg. Electric wins however. There is not shortage of gasoline and price per gallon is too low to stimulate movement to electrics or coasting. I coast alone but now have a coasting habit.
Re: Electric Motors Still 3x Better
Note, in cold weather it is very efficient to use the "waste" heat from an internal combustion engine to heat the car. The term for this concept is co-generation. In addition an electric car can be no more efficient than the power generation facility that produces the electricity used by the car and to claim that the total efficiency is three times that of an internal combustion engine is a gross exaggeration. Those that advocate plug-able hybrids with an efficient internal combustion engine partnered with an advanced battery, such as the one produced by Altairoano, are on the right track for the most efficient and practical vehicle.
Why not integrate this into the GM volt as it uses an electric motor to drive the vehicle but utilizes a small generator to charge the batteries when they are low. if you integrate this technology into the generator you wouldnt have to worry about load change as it would be a near constant consisntent load?
Guest (Arthur Hanson)
Mercedes has already built and tested an engine that does this
Why go to the complicated and costly HCCI engine to improve engine efficiency?
Cutting a few grooves, shaving of the head to improve CR as per US Patent of Mr Somender Singh will increase mileage by 20% plus, reduce exhaust pollution and keep the engine oil cleaner for a longer period and this has been achieved in hundreds of cars. Details are available in his
website www.somender-singh.com.(email: garudarad1@rediffmail.com. The cost of modification is approx.US$350 in India. please find below the engine exhaust analysis of a modified 1000cc car taken from the web:
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2nd September 2006, 19:20 #82 (permalink)
Kaizer Sozay
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Join Date: Apr 2005
Location: Bombay Blues!!!
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The PUC Report!!!
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A PUC Report in a way vaildates the change in performance of the engine.
I got the PUC done today on a PUC machine called ULTRA-TEC the readings are as follows (Both the readings are from the same machine at the same petrol pump)
Reading ----- Today----- 1 Year Ago
CO: ----- 0.326% Vol -----1.459% Vol
CO2:----- 12.19%vol ------11.49% Vol
HC: ----- 135PPM Vol----- 234PPM Vol
O2: ----- 0.00% Vol -----3.24% Vol
Lamda: ----- 0.982 -----1.113
AFR: ----- 14.43 -----16.36
I do not know what these readouts like Lambda & AFR are but every reading shows a significant Drop
The Permissible limit for CO is 3% The reading now is 1/10th of that All I can gather from this is that the Engine is Much More Enviormentally Friendly.
This is only possible if the combustion process is Complete & there is no Un burnt fuel being thrown out from the exhaust,
Also There is a lot of water being thrown out from the tail pipe.
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Last edited by Kaizer Sozay : 2nd September 2006 at 19:25.
Unquote
When will the car manufacturers incorprate this modification in the cars produced by them? Such a modification during the car manufacturing stage will cost very little and benefit the car owners by lowering the running cost of their cars.
Why one or the other? Why not both? For that matter, build a motor into the flywheel for a "soft hybrid". See how it stacks up against a Sterling external-combustion engine. We need to combine known technologies when they can synergize without sacrificing reliability.
My favorite near-term would be a plug in hybrid with a small high efficiency engine such as diesel or what is being proposed here, elec motor, plus thin film PV panels on the roof, ultra low drag and light weight design. If my Prius can get 50 real world mpg, a vehicle like that should be capable of 70-90, perhaps?
Individuals who started with a Prius platform created a plug in hybrid and then an upgrade kit, showing Toyota it could be done and now Toyota has taken up the torch. The same could be done to retrofit PVs onto the plug in version, or Singh the engine's head, or add a Sterling generator to the exhaust system. I say, go for it!
Here is what I remember from my combustion class: AFR is most likely Air Fuel Ratio (wtair/wtfuel). Lambda looks like equivalence ratio which is AFR/AFRstoichiometric. So, 16.36/1.113=14.699 and 14.43/.982=14.695 so it looks like you're using same fuel (14.7 to 1 is right for gasoline). However, because the previous reading is above stoichiometric (more air than absolutely necessary) and second is below stoichiometric (you can also tell this by 02 output) the combustion dynamics are different, probably higher temp etc. Point being to compare like fruit you want to run same AFR for both cases.
AFR is air fuel ratio. The "perfect" AFR is called stoichiometrics or fuel stochiometry. This would be 14.7:1 on a gasoline engine. It does vary acording to several indicators such as altitude, temperature, and fuel density(type and even grade of fuel).
The correct AFR is the ultimate goal of all things mechanical in combustion engines. When a perfect combustion takes place all the fuel is burned and a large amount of CO2 is expelled. The problem is that a "perfect" AFR is not easily obtained at cruise speeds or idle so getting very close is much desired. Also with engine advances such as EGR's, and many other things, there has been a need to lower the AFR some for the desired emissions. This can sometimes be 13.8 to 14.5:1.
This is my though:
The desired AFR that an engine was designed to operate at should actually be included in vehicle factory information including area of manufacturer tests.
This could be a great thing for a technician during testing. All that would be required would be a program with a variable change compensation chart. Then no matter where you would be located the desired AFR could be reflected for that location. A technician and the consumer would then be able to tell at a glance if the vehicle was operating at desired factory specifications for maximum fuel economy. A green lettered indicator, for acceptable, could indicate that a certain criteria has been met, and all the useless information to the layman could be explained with final numbers and an answer to; does my car still perform to factory specification?
Yes there are computations for this but look up air fuel ratio on Wikipedia and see if you have the math skills to compute this with the information you have.
I am just a technician and have to deal with what I am given. Too bad I didn't go to MIT
Good luck.
Am a trained mechanic from Kenya Polytchenic university, i would like to know more from your organistion. Am soon opening an Auto Parts shop and am considering these organisation as my main supplier.
Could this be something along what Smokey Yunick may have developed in the early 80's? Though i believe his design still used spark plugs it did use something he refered to as a homogenizer to premix a pre-heated air fuel mixture. It's just what i recall reading about 25 years ago. The article also stated that his design was such that it wouldn't pre-detonate or knock even when attempting to get the vehicle moving in high gear.
It could be. Predetonation or knock concerns, which would have been more of a problem then, can be almost be a non-existant concern with current technology. When an almost(as close as possible) perfect AFR is obtainted there will be no "knock".
But I have a more efficent engine
yes I have a spark fired engine that uses 50% Less fuel than normal, this is true with low and meduim loads, at high loads its worse but its only my second prototype.
My city and hwy consumptions are very similar.
I am doing 40 mpg(imp) average eg city/hwy.
I have video evdence of idle fuel consumption on youtube if you want to check it out search smoking2wheels note there are 5 clips in the test.
Whats an engine worth that is 40% thermally efficent??????
Ps: my record is near 100% better but its at 80 km/h
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18 Comments
WHAT ABOUT THIS IN...
A wankel engine?, as other reseach using a dual injection system (gasolina and etanol), the principle of engine efficiency is based in drastic increase of compresion ratio to 20:1 instead of actual 8:1.
A rotatory engine can handle this sistem more efficiently than a reciprocal and reduce engine size keeping HP.
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