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Is there a future for hybrid vehicles? Part 2

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eric123
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re: Is there a future for hybrid vehicles? Part 2
eric123   9/15/2010 5:12:15 PM
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Dave, Excellent article. Understanding the need for space limitations there is one element of certain hybrid systems which should be mentioned, which is the change from an Otto cycle to Akinson cycle ICE which ipproves the IEC fuel consuption performance at the trade off of a loss of low RPM torque. This low end torque is replaced by the electric motor. The advantage of the Akinson cycle ICE is a driver for better fuel economy but performance wise not an option for pure ICE vehicles. Also it should be noted that the hybrids being on the road are providing the real word experence with a number of technologies which will develop the engineering (and other disiplines) knowledge for further development into fuel cells or battery power vehicles. Eric Honsowetz

mr88cet
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re: Is there a future for hybrid vehicles? Part 2
mr88cet   9/15/2010 4:52:51 PM
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One thing I've found curious is the critique, often from German automakers, that power-split hybrids are complicated, requiring large "part" counts. For that they cite the need for two motor/generators. Some of those automakers therefore promote pure-parallel hybrids. I would buy the argument if you count a transmission as one "part." As we know, a transmission could easily consist of 10-20 individual gears, various hydraulic subsystems, solid- or fluid-mechanical clutches, and so forth. The equivalent of the transmission on a power-split hybrid consists of a planetary-gear system (5-6 total gears), and the two MGs. At least by that count, power-split hybrids have a far smaller part count, but then again, you also have to add electrical parts, to both.

AlexKovnat
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re: Is there a future for hybrid vehicles? Part 2
AlexKovnat   9/15/2010 2:00:17 PM
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A problem I see with fuel cells is, they are fussy things regarding fuel. The only fuel they can handle all that easily, is hydrogen. How are you going to distribute hydrogen to thousands of service stations, or millions of homes? You would need a new system of pipelines. And if you decide to reform natural gas on site to provide hydrogen, you negate perhaps a good part of the efficiency advantage of a fuel cell vis-a-vis use of natural gas directly in a well-designed piston engine. And now, the matter of pressure. The only way to get a decent range with a hydrogen-fueled vehicle is to use pressures of 5000 psi, and I've heard talk of pressures as high as 10,000 pounds per square inch. I see a problem with this. Compression to such a pressure would also negate a part of the efficiency advantage claimed for fuel cells. By contrast, compressed NG vehicles use lesser maximum storage pressure, i.e. 3600 psi. Direct Methanol fuel cells could be utilized, but people concerned about safety are going to want to add ingredients to methanol to make flames more visible in case of tanker disasters, and also ingredients to create a bitter taste owing to methanol's well-knwon toxicity. Fuel cells, being such fussy things, might not tolerate said additives. Since a fuel cell doesn't develop mechanical torque, you would need an electric drive system (including batteries) similar to the Chevrolet Volt. This would create cost disadvantages similar to those cited for the Volt or the Prius. So while I hate to burst anyone's bubble, I would rather not own a fuel cell vehicle for my own use.

TOEKNEE0
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re: Is there a future for hybrid vehicles? Part 2
TOEKNEE0   9/15/2010 8:56:05 AM
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In Australia there has been E10 & E20 fuel blends available for some time now and soon we will be having E85(85% Ethanol) fuel blend available. So whats holding America back? I notice the Dodges we get here have "FlexiFuel/E85" badges on the rear....

GREAT-Terry
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re: Is there a future for hybrid vehicles? Part 2
GREAT-Terry   9/15/2010 2:45:04 AM
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I agree there are still rooms of improvement on ICE, but this is also true for the electric motor and battery technology! Why can't keep on improving both so that finally a plug-in hybrid can be well adopted in all kind of cars? Fuel cell is only a kind of energy source so we are not limited to gasoline. The idea is to make good use of "hybrid". A "hybrid" indeed should be considered to mix two or more energy delivering system so as to fulfill the wide loading (speed/mileage/torque) range of vehicle as there all energy delivering system has there sweet spot (or range) of efficient energy delivery. We just need to make the whole range as flat as possible by using different tool at different sessions.

DrQuine
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re: Is there a future for hybrid vehicles? Part 2
DrQuine   9/14/2010 11:53:59 PM
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Urban vehicles spend a lot of time inching ahead in traffic. Why not modify conventional vehicles to allow a small electric motor to inch the vehicle ahead in traffic? It would enable vehicles to "auto shut off" their motors (as hybrids often do and some Audi diesels do in Europe) when stuck in traffic. The gear shift could have a position for battery only - or the gas pedal could have a very low speed range in which the electric motor propelled the vehicle. Much of the traffic benefit of hybrid driving could be achieved at a very low cost across a broad spectrum of vehicles.

Kinnar
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re: Is there a future for hybrid vehicles? Part 2
Kinnar   9/11/2010 11:02:55 AM
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Good Comment that cross votes the opinion of the author. But improvement in ICE in a way it will give better efficiency compared to hybrid, will be more cost effective for the world, as 90% of the roads are flat, I mean only 10% of the roads are in the hilly area. But city traffic is the point where ICE needs some improvement, that starting mechanism (Starter) should be modified in a way engine can be turned on and off with less battery power consumption and automatic. That way city traffic drive can be made cost effective.

Ecspansion
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re: Is there a future for hybrid vehicles? Part 2
Ecspansion   9/10/2010 8:34:41 PM
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Good analysis of the reasons HEV's have better fuel economy than pure ICE cars. Of course there are some ICE cars that get 40-50 mpg in highway, but they are small, light, with no AC, power seats, power windows, air bags, power side mirrors, etc. If same small and ligh vehicle uses Hybrid engine, it can get 60+mpg (old 3 cylinder Honda Insight). Also try getting 40-50 mpg in an ICE car in stop and go traffic. Most Hybrids get better milage the worse the traffic gets. Regarding conservation of energy, you did not mention potential energy. When driving downhill, the potential energy of the car is converted to kinetic and converted to electric energy by the regenerative breaking action of the MG. Of course only as much energy as can be stored in the battery can be recovered. When driving up-hill, the stored energy is used to reduce the load on the Gas engine. Pure ICE cars have no way of recovering this lost potential (or kinetic) energy. It is true that Hybrids cost more, but compare the extra cost to the cost of options like 8 way adjustable power seat, auto-dimming rear-view mirror, 8 speaker Stereo and the like, and suddenly the extra cost of the Hybrid becomes more justifyable.

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