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Just How Clean Is The Chevrolet Volt?

California regulators raise some concerns about emissions.

by on Oct.25, 2010

The 2011 Chevrolet Volt takes a hit in California's emissions tests.

Just how green is the Chevrolet Volt?  Not nearly as much as you might think – at least according to the results of a new test by the California Air Resources Board.

The agency has ruled that General Motors’ new plug-in hybrid falls short of not only conventional hybrids, like the Toyota Prius and Honda Insight but even the new diesel-powered Jetta TDI in a key test.  As a result, Volt not only doesn’t get a coveted PZEV (for Partial Zero-Emission Vehicle) rating but misses the next-best SULEV category and slips into the rankings as a ULEV vehicle.

But observers caution that the 2011 Chevy Volt may be taking hits because of its own efficiencies, ironically.  And California regulators may take steps to modify their rules so vehicles like Volt, designed to run primarily in electric mode, get the technical benefit of the doubt.

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The eagerly-awaited Volt has faced its fair share of controversy lately.  Earlier this month, a debate began swirling over what the Chevy battery car actually should be called.  Since the debut of the original Volt concept, GM had argued that it was an “extended-range electric vehicles,” since the car’s wheels, according to the maker, would only ever be driven by its two electric motors.

More recently, however, it has turned out that Volt gets a direct mechanical boost from its internal combustion engine under certain high-demand situations.  That has prompted even the Society of Automotive Engineers to begin referring to the 2011 Chevy as a plug-in hybrid.

(Just how DOES Volt work? Click Here for more.)

But GM’s argument remains reasonable: federal data show that up to 70% of Americans drive less than 40 miles a day, about what the 2011 Chevrolet Volt will get on battery power under typical conditions.  The problem is that this means the car’s onboard, 1.4-liter 4-cylinder engine will seldom fire up.

( test drives the 2011 Chevrolet Volt. Click Here for the review.)

When it does, the CARB test found that it produces an average 1.3 grams per mile of carbon monoxide, which lands it in the ULEV category.  To qualify as SULEV Volt would need to drop below 1.0 gram per mile.

The test does not average out emissions to account for the fact that under battery power the little Chevy produces no emissions at all – something a proposed revision, the CARB LEV III ruleset, would take into consideration.

The possibility that Volt owners might go weeks, even months, without using gasoline might sound great to environmentalists – and those who wish to curb our dependence upon foreign oil.  But there’s a downside.  Like a fine wine, gas ages over time, and Chevy engineers had to come up with a way to deal with older gas.

They also had to design Volt so that as it approached transition – the point where the battery runs down and the I-4 engine fires up – the vehicle’s catalytic convertor is pre-heated in order to reduce emissions once it shifts to gasoline mode.

Meanwhile, the first-year Volt won’t qualify for the much sought-after California HOV pass, the decal that lets a vehicle run in the car pool lane even with just one person aboard.  That and a $5,000 state incentive will have to wait until 2012, when GM upgrades the Volt’s emissions system to PZEV, eliminating evaporative emissions.

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