Monday, October 11, 2010

Chevrolet Volt Reliability Analysis and Report

Don't call the Volt a plug-in hybrid. GM engineers steadfastly claim that the Volt is an electric vehicle with an on-board generator, or in their words, an “EV with a range extender." We tend to favor the former. Semantics aside, the Volt is the most thoroughly tested car in GM's history, a new type of vehicle that vehicle line director Tony Posawatz claims is overengineered because, “Frankly, we have to change minds about the quality of GM vehicles." Ever since the concept debuted in Detroit in 2007, we've covered every tidbit Chevy felt worthy to release. Now, we've finally spent three unsupervised days and over 900 miles in the car that has been called “GM's moonshot." Does it deliver?

The Specs


With a 105.7-inch wheelbase and 177.0-inch exterior length, the Volt is about the same size as the upcoming Chevy Cruze, a car that shares some of the Volt's underpinnings. The big difference of course is that the Volt's 16 kwh T-shaped Toyota Prius. This arrangement allows both electric motors to power the wheels, a strategy that keeps each motor in its most efficient—and refined—operating mode.

As befitting this next-gen car, two seven-inch WVGA screens—one in the center console, the other in the gauge cluster—display relevant information and, of course, an efficiency coach with vibrant graphics. There's even a tutorial mode. While the standard heated seats and power windows seem like power hogs in an EV, the engineers counter that both actually save energy by encouraging drivers to open the windows in the summer and use less heat in the winter.

Capacitive-touch sensors operate basic functions like HVAC and the audio systems. There's also a smartphone app that allows user to specify start times and to precondition the cabin while the car is still plugged in.

The Volt will be monitored as never before thanks to GM's OnStar service. The usually pay-by-the-month feature will be free for five years on the Volt, primarily so data about the car and the health of the battery can be beamed back to GM HQ.

2011 Chevy Volt Reliability test photos


The Drive


Despite the Volt's unconventional powertrain, our test Volt arrived with the instructions, “Just use it like an everyday car." There wasn't even an owner's manual on board.

First impression from behind the wheel: It's library quiet inside. Sounds that usually take a back seat to the engine, like from the tires and suspension impacts, are now front and center. There's also a slight whir from the electric motor and a minor hum from the battery—we think—that gets more noticeable under braking.

Acceleration is as advertised—initially snappy and punchy at low speeds—but it trails off as velocity rises. In our test, the Volt reached 60 mph in 8.82 seconds, about the same as a typical four-cylinder sedan. An electronic speed limiter steps in at 101 mph, a speed at which the Volt tracks like it's made for the Autobahn.

Stopping from 60 mph requires 118.97 feet, which is quite good considering the Volt's low rolling resistance tires and 3790-pound weight. Unlike many hybrids, the Volt's brake pedal doesn't suffer from a step in pedal effort as the computer attempts to blend the retarding force from the brakes and regenerative system. But, oddly, the car stops with more force as the car's speed drops, despite keeping constant pressure on the pedal.

Otherwise, the Volt's a refined ride, with a suspension that feels tuned more toward the comfort end. The electrically-assisted steering is speed-dependant and the effort lightens dramatically at low speeds.

The dash readout has numerous graphics to display power flow and when the battery is discharged (we'll get to the EV range in a minute). Without the gauge we might not have noticed when the gas engine kicked on—it's that smooth. The engine does rev up during acceleration, which is definitely audible—but like any CVT engine speed is not proportional to vehicle speed.

There are three drive modes, normal, sport, and mountain. Switching to the sport mode causes the engine to rev higher, and the response to the “throttle" pedal is quicker. The mountain mode is meant to be used in special cases, like when you're crossing a high-altitude pass in the Rockies. When engaged, the engine revs to what feels like its redline—there's no tachometer to display rpm—and remains there regardless of vehicle speed. In this mode, the computer uses the engine to charge the battery and increase the charge buffer so the car maintains performance on a long, steep grade. “Remember," said Larry Nitz, GM executive director of hybrid and electrical powertrain engineering, “We've got a half-size engine." That half-size engine is hooked to a 74-hp generator—additional energy must come from the battery—so the mountain mode prepares by increasing the charge in the battery. “In the mountain mode," Nitz says, “the Volt zips right up Loveland Pass in Colorado at over 70 mph."

Michigan has no such grades so we couldn't test the mode's effectiveness, but when we switched it on the din in the cabin was raucous enough that we'd only use this feature if needed.

Any downsides? For one, the interior feels a bit like plastic land, a tad low-rent for what is otherwise an exceedingly refined $41,000 car. Some driver's weren't fond of the dash pads that are there to visually break up the distance between the base of the windshield and the dash's trailing edge.

There were no complaints about the exterior styling, however. If anything, the exterior suggests a sporty driving experience that the Volt's handling doesn't really deliver. But at least Chevy's designers penned an aggressive body that's a clean brake from the usual jellybean hybrid. We'd buy the car on looks alone.



Source: Popular Mechanics

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