Posted on 10/11/2010 12:10:12 PM PDT by dangerdoc
Interesting news from General Motors today that's resulted in some puzzled expressions at Engadget HQ. We've learned that the Volt, which Chevrolet has been making quite a fuss about calling an "extended range electric vehicle," is actually just a traditional hybrid with some... potentially misleading marketing behind it. Since the concept stage the company has been saying how the onboard internal combustion engine was just to charge the batteries, that only the electric motors (there are two) are actually connected to the drivetrain. Indeed that's what we were told in person when we test drove the thing back in March. We're now learning that is not the case, that the Volt's gasoline engine can directly provide power to the wheels in concert with the electric motors.
Is that a problem? In terms of efficiency the answer is "apparently not," as we're guessing the car would not have been designed this way if it weren't the most frugal way to go. So, why all the deception? Why insist this isn't just a hybrid when it apparently is? When the company went looking for a government bailout it was in part awarded one because of the innovation shown in the Volt. Now that we're learning the Volt is basically just a plug-in hybrid with a bigger than average battery pack (Popular Mechanics is finding 30-odd miles of purely electric range), we're left wondering: where's the innovation?
This epicyclic drive is pretty innovative. The prius drive train never locks any of the elements meaning that there is a ratio of at all times between the 3 elements sun planets and ring, at some point the ice engine must start spinning its part or the smaller motor gen overspeeds. The volt drives its epicyclic differently and has 3 clutches to stop and start different elements at different speeds. at all times the primary electric drive motor must supply torque, however above 70 mph the primary motor starts to over speed so the second motor is clutched in and together with the sun and ring gears they lower the speed of the primary motor to an acceptable level. when the battery is depleted a second clutch closes and the engine is coupled to the smaller motor/generator providing torque to it as well as the ring gear which previously was driven solely by the smaller motor/gen now the smaller motor consumes torque to generate electricity for sustaining the battery pack level and simultaneously to power the primary electric motor. The deficit of previously supplied torque from the smaller motor/gen is now mechanical supplied via the clutch and ring gear this is genius. The third clutch is to disconnect the smaller motor/gen from the ring gear at low speeds and allow the ice to turn it as a true generator in pure series hybrid mode again genius. This is a series electric + mechanical parallel+ electric cvt system the best of all the current hybrid modes. Should be a winner technically.
No mining for rare earth elements to make the batteries.
No battery disposal issues.
No possible electrocution issues for Emergency Personnel when rescuing occupants after a collision.
No $10,000 Taxpayer funded Tax Credits and Rebates to make the car affordable for the “working class”.
It should be noted that they purposely left out clutch 4 which would have allowed the ICE to turn the wheels directly as this would void the EV tax credit. A clutch on the sun gear to disconnect the primary electric drive motor and a band clutch or one way gear to hold the planet carrier would allow the ICE a direct mechanical connection to the epicyclic output geared for hyway speed at the final ratio would have allowed even greater hwy mileage since sending torque via the motor/gen to the inverter to the primary drive motor in electric cvt mode at hwy speed is inherently less efficient than a direct drive but alas they need the tax credit so this clutch was left out.
“two words, Turbo Diesel..” four words Tier two Bin Five all light duty engines diesel or petrol must meet this standard in all 50 states and CARB is going to subT2B5 very soon. The emission control cats and particulate filters needed to meet T2B5 add thousands to the cost of a diesel here in the states euro diesel have to hit euro 5 which is an order of magnitude dirtier than T2B5, currently only Nox SCR cats plus DPF meet T2B5 and that requires urea injections only a few Benz and VW have invested in teh capital expenses to bring T2b5 engines here.
All “academic” anyway...I will never go near a “Government Motors” product...latest debacle is $500,000,000.00 of taxpayer money to Mexico for plant upgrades! They had better pay off that 61% ($50 Billion) government stake fast, or it is bankruptcy part II.
Been a Mopar guy all my life, but nothing but Ford or Honda for me in the future!
Also our refinery infrastructure is not such to have large amounts of diesel light duty vehicles, we get 19.5 gallons of petrol and only 9 ish of diesel per 42 gal barrel here in the states, we would have to retool our refineries to start oligomerizing short chain to long chain paraffins this would be massively expensive.
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