Re: G.M. ‘Officially’ Introduces 2011 Chevrolet Volt Amid Controversy

Apples and oranges. For one, like any other car engine that "requires" premium fuel, the generator engine in the Volt will run fine on regular gas.

Secondly hybrids, like the Toyota and Ford models, can be motivated by the gas engine alone. The Volt 4cy engine is not capable of motivating the vehicle by itself, it can only assist at highway speeds.

The Volts is an electrically power vehicle, it needs a predetermined voltage level, or it can not be driven. In Toyota and Ford hybrid models can be driven even if the voltage is zero. Huge difference

3rd paragraph: "A 1.4-liter engine running on premium gasoline...". $40K > plus and it has to run on $premium$ ? > > > G.M. ?Officially? Introduces 2011 Chevrolet Volt Amid Controversy >
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> General Motors began its official press introduction of the 2011 Chevrolet > Volt on Sunday. Yes, that would be the same vehicle G.M. has been > introducing with a barrage of auto show appearances and news releases > since 2007. > > G.M.?s press materials call the Volt ?an electric vehicle with extended > range,? though the company has acknowledged all along that this electric > vehicle would have a gasoline engine under the hood. And while G.M. has > provided more product information than was available in the past, its > continued characterization of the car as ?purely electrically driven? > glosses over operational details that suggest otherwise. > > What G.M. has told the press is that the Volt can cover 25 to 50 miles on > electric power alone, depending on the terrain, driving techniques and > temperature. A 1.4-liter engine running on premium gasoline turns a > generator that can power the electric drive motor and extend the range up > to an additional 310 miles before needing to refuel the 9.3-gallon gas > tank. The Volt?s electric motor produces 149 horsepower and can accelerate > the four-passenger sedan to 60 miles an hour in less than nine seconds. > G.M. claims a top speed of 100 miles an hour. > > Extensive wind tunnel work has reportedly made Volt the most aerodynamic > car Chevrolet has ever produced, with a drag coefficient of 0.28. The > vehicle platform is typical of today?s automobiles with a unitized body > and frame riding on a MacPherson strut suspension. > > So what product feature has G.M. neglected to mention? Simply that when > driving in extended range mode at high speeds ? when the battery has run > down and the gas engine is powering the generator ? the engine provides > some assist by means of a planetary gear set that couples it (G.M says > ?indirectly?) to the powertrain. > > In terms of vehicle dynamics and performance, that may well be an > advantage. In terms of electric-vehicle categorization, it clouds the > picture, making the Volt?s engineering layout more like a Toyota Prius, > which is a parallel hybrid, than G.M had led journalists to believe. > > G.M.?s stance, at least in the materials distributed to the press, is that > the Volt?s design is singular: ?The Chevrolet Volt is not a hybrid. It is > a one-of-a-kind, all-electrically driven vehicle designed and engineered > to operate in all climates.? > > That depends on how one defines a hybrid. Logically, any vehicle equipped > with both a combustion engine and an electric motor is a hybrid. In > keeping with the electric powertrain terminology common to diesel-electric > locomotives, the Volt would best be described as a series hybrid. > > G.M.?s insistence that the car is fully electric is hard to understand in > light of the fact that the gas engine provides motive power under certain > conditions. > > A G.M. spokesman, Tom Wilkinson, said, ?There is some mechanical drive > force at high speed. The engineers wanted to maximize the overall > performance and eliminate any potential flat spots in the acceleration > curve.? > > When asked why G.M. didn?t mention this high-speed gas-engine assist > previously, Doug Parks, a global electric vehicle executive for G.M., said > that the automaker chose not to publicize this feature to protect the > technology during the process of obtaining patents. > > In the end, how the vehicle performs in the real world will be much more > important than any terminology. But it may be a while before that > information is available. Numerous publications are anxious to conduct > long-term tests, and some have complained publicly because they?ve been > unable to secure cars. > > ?We simply don?t have enough cars at this time to satisfy the demand,? Mr. > Wilkinson said. A two-week press event is under way, and almost every > available Volt is being used at that event. What?s more, all of the Volts > available for testing are preproduction cars. Production-line vehicles are > not yet available. > > > -- > Service Guarantees Citizenship
Reply to
Mike
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Mine from Ford says regular gas only.

What was GM th> Apples and oranges. For one, like any other car engine that "requires"

Reply to
Canuck57

Very few twenty year old Fords used premium fuel. ;)

Reply to
Mike

No, they can't. Without MG1 providing a countertorque on the sun gear of the PSD the engine torque has nowhere to go so the engine freewheels. Once MG1 is providing a countertorque, either by electricity being drawn off or by it being turned backwards as a motor then can the torque from the engine can go from the planet gears to the ring gear and hence the wheels. Or if MG1 is generating it electrically goes from MG1 to the battery and/or directly to MG2. MG2, the ring gear, and the wheels are all directly linked. This is what makes them series-parallel hybrids not just series like the Volt or just parallel like the Honda IMA system.

Toyota hybrids don't have a 12v starter motor, without HV to spin MG1 and crank up the engine the vehicle goes nowhere. Honda models (or at least the original Insight) have a 12v starter for backup and can be driven with a dead HV battery.

Reply to
Daniel who wants to know

What? Once MG1 is providing a countertorque, (SIC) either by electricity being drawn off or by it being turned backwards as a motor then can the torque from the engine can go from the planet gears (etc.)

Reply to
Mike

Look at it like an open differential with say 4.10 gears. Turn the prop/drive shaft at 410 rpm and the wheels turn at 100 rpm. If you let one side freewheel the other side stops. If you now stop one wheel the other turns at 200 rpm. If you drive one side backwards at 100 rpm the other turns at 300.

This is how the PSD works as a virtual CVT. The driveshaft (pinion gear) is equivalent to the planet gears, one axle shaft (the sun gear) is connected to MG1 and the other axle shaft (the ring gear) is connected to MG2 and the final drive and thus the wheels. If you let MG1 freewheel the engine also freewheels.

Per

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if you are going 60MPH and all 3 parts of the PSD were turning the same speed the engine, MG1, and MG2 would all be turning at about 3575 rpm. If you now want an overdrive effect and want the engine to instead turn at

2000 rpm you need to drive MG1 backwards at about 2100 rpm. This is known as heretical mode or energy recirculate mode because during this mode the roles of the 2 MGs are reversed. MG2 generates and MG1 consumes. Some energy goes in a loop from MG1-sun-planet-ring-MG2-inverter and back to MG1. You would think this would be too lossy but apparently it is more efficient/less lossy than running the engine at a higher rpm.
Reply to
Daniel who wants to know

Got it!!

Reply to
Mike

took the test drive last month at the local Sustainable Energy HQ. The local tree-huggers and "electric purists" were casting shame on the Volt.

Chevy struck a neat balance between range and the downside of having to haul around a massive battery. This has cost, environmental and rear seat benefits. >80% of my trips will be all electric,

Reply to
pete jensen

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