• Oct 7th 2009 at 1:31PM
  • 23
Chevrolet Volt prototype at Pikes Peak - click above for high-res image gallery

One of the main concerns that many people have about the Chevy Volt is how well it will perform when running in charge sustaining mode with the engine-generator cranking away. While we haven't yet had an opportunity to try out any of the Volts or Cruze mules operating in this fashion, the engineering team has. John Blanchard, the lead calibration engineer for the engine-generator, has posted on the Voltage blog about a recent trip to Pikes Peak in Colorado with the Volt prototypes.

According to Blanchard, the Volt got to the top of the 14,110 foot peak faster than anticipated and did a good job of replenishing the battery on the downhill run. What is not clear is exactly what GM has been anticipating. The engine generator only puts out a bit over 100 hp while the traction motor has a 160 hp output. We know the Volt will be able to draw down the battery below its 30-35 percent depletion point for transient full power acceleration, using regen and surplus energy from the generator to replenish it back to depleted mode when the load drops off.

A sustained uphill run like this means that either the car will loose a significant amount of performance or draw the battery way down. Until we have a chance to talk to Blanchard or someone else on the team, we won't know for sure which it is.

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    • 1 Second Ago
      • 5 Years Ago
      How much will the generator degrade at that high an altitude? It's not going to put out 100hp.
        • 5 Years Ago
        I've personally driven up Pike's Peak, and you'll be lucky to do 10 MPH once you catch up to the first minivan. There are few guard rails, so parents get rather nervous in the turns.

        Even when it's gasping for air at 14,000 feet, the 100 HP generator will be more than enough to get you to the top.
      • 5 Years Ago
      Hmmm. I'm not sure this is the best test. In my own area (Sacramento) one of two widely traveled mountain runs is over the Sierra on US50; From the town of El Dorado Hills to Echo Summit is about 67 miles of twisty mountain highway with an elevation change from ~200 to over 7200 feet above sea level. It's almost all uphill, so there's little chance to recapture energy with regen brakes. Moreover, many weekend tourists are from the SF Bay Area, so their Volts will be in charge sustaining mode long before the first foothill.

      Any thoughts on how the Volt would perform in this scenario?
      • 5 Years Ago
      You're not going to use 160hp all the way up the mountain, only if you floor it continuously, in which case you're not going to need to worry about anything anymore because that's the life of a pancake at the bottom of a cliff. The average hp needed to climb the mountain [at a reasonable less-than-race speed] is going to be much less than 100hp (especially considering the electric torque which will maintain speed without strain). If you want to race up at 70mph, you're not going to do it in a Volt, or even a Camry, so comparing the Volt to a high horsepower sports car or hill climb race car is pointless and paranoid.
      • 5 Years Ago
      In a sustained climb like this it will limit the performance. But simply slowing a bit will fix you right up (like a VW van!). Hopefully 100HP is enough to sustain 55mph. 65mph is probably a dream.

      Also, "lose", not "loose".
        • 5 Years Ago
        Regarding: Also, "lose", not "loose".

        Amen to that! It's bad enough that the general public posting replies can't keep "lose" and "loose" straight, but if you're posting articles presumably you're supposed to know how to write!
        • 5 Years Ago
        If you find any spelling mistake you are more than welcome to keep them for free! ;o)
      • 5 Years Ago
      "What is not clear is exactly what GM has been anticipating. "

      For 100 hp, the theoretical fastest you'd get there is :

      14,110 ft * 4000 lbs / (100 * 550 ft*lbs/sec) = 17 minutes

      at 12.42 miles, that's 43.9 mph which is about as fast as any sane person would want to drive a Volt up Pike's peak.

      If you lose 20% to drag, rolling resistance, etc., you're gonna climb Pike's Peak at 35 mph. Sounds acceptable to me.
        • 5 Years Ago
        "I think you're right, the generator shouldn't be the limiting factor. The battery capacity (under normal charge/discharge cycle) is supposed to be 8 kWh. With your assumption of 4000 lb total weight, a 4700-ft climb requires only 7 kWh of energy."

        I disagree with your assumptions.

        Unless you live next door to Pike's Peak, the battery pack will be fully discharged (or nearly so) when you get there.
        • 5 Years Ago
        Forget everything I said - the elevation ascended is only 4,721 ft.

        The hp should not be the limiting factor.
        • 5 Years Ago

        "1994: The Open wheel division record was set by Robby Unser at 10:05.85. He was driving a 1993 ADT/Speedway chassis powered by a Chevrolet engine. " - Wikipedia

        Thats 73.8 mph
        • 5 Years Ago

        I'm assuming that the Volt and its occupants and cargo weighed 4000 lbs.
        • 5 Years Ago
        I think you're right, the generator shouldn't be the limiting factor. The battery capacity (under normal charge/discharge cycle) is supposed to be 8 kWh. With your assumption of 4000 lb total weight, a 4700-ft climb requires only 7 kWh of energy.

        Road friction and air resistance would add to that, but even if it added 50%, you're only 2.5 kWh short. The 53kW generator on the Volt will provide that in less than 3 minutes.
      • 5 Years Ago
      Most likely it will still be able to pass most the Subaru Loyale's that are still on the road in Colorado.
        • 5 Years Ago
        Doubt it... But it wouldn't be a problematic drive either by any means. When you talk about a subaru you are talking about an AWD hill climbing machine...
      • 5 Years Ago
      Has there been a power bump for the generator?

      All the stuff I saw says about 50KW/70HP.

      Now this story says 100HP. That is a fair jump.
        • 5 Years Ago
        "There's no mention of a 100 hp generator in the story."

        Look up, way up at the story. 3rd line second paragraph.

        "The engine generator only puts out a bit over 100 hp"
        • 5 Years Ago
        There's no mention of a 100 hp generator in the story. Nor have I heard the Volt's traction motor rated at 160 hp output. Wikipedia still says "111 kW (149 hp) electric motor, 1.4 L 4-cylinder for powering 53 kW (71 hp) generator."

        Most people never user all the power their cars provide, they just want to feel the car surge forward when they press the go pedal. Many drivers complain if they have to drive in a lower gear or mash the pedal to the floor to go uphill.
      • 5 Years Ago
      "Do not use a cannon to kill mosquito."

      That's what the volt is, a complex answer to a simple problem.

      Its. overpriced, over-tech'd, and NOT unlike someone I know in the White House the savior himself. The only way this thing could save GM is if its got the fat profits built into it that their trucks do.

      Also, why years into developement are they just now driving up a mountain in the thing???

      Is everyone aware the Chinese have been building cars just like this for over 2 years now, about $19,000 U.S. money BTW.

      The biggest waste of billions of dollars since, oh wait, since the bailout. Since the fake stimulus, since... where does it end?!
        • 5 Years Ago
        Man are you slow in the head or something? This isn't a simple problem and the expensive first step that the volt is taking is a crucial one if GM wants to eventually make the electric technology more viable for the future. The volt isn't about saving money at the pump right now or being an economical decision, it's a technological showpiece.
        • 5 Years Ago
        Simple problem? You mean getting good fuel economy is a simple problem? My, all those automakers out there must be full of engineers and researcher who know nothing, because everyone is spending billions of dollars for just fun.

        Why just now driving up a mountain? Because developing a new car, and especially with a concept like this, takes far more work than people just making uninformed assumptions and talking away with keyboard.

        Enlighten me, which Chinese car 'just like this' for over 2 years? $19,000 in China is not the same as $19,000 in the US, by the way. Travel around a bit, will you?

        I hope you're not a policymaker, because that's what our bipartisan 'leaders' at Capitol are doing these days; bashing the people working their arse off for not knowing anything. Surely all those lawmakers got A's in their advanced Physics and Chemistry courses, right?
      • 5 Years Ago
      Frankly, I'm not sure how many people would want to travel more than 65 mph in a family sedan going up Pike's Peak...

      But in terms of flat road performance, it always amazes me just how little energy is actually required to move a car through the area.

      Assuming the Volt's got a Cd of 0.28, and a frontal area of 20 sq. ft, it requires just a little more than 13 hp at the wheels to keep it trucking along at 65 mph, and only 20 hp for 75 mph.

      The fact that we have 250+ hp daily people movers is pretty staggering.
        • 5 Years Ago
        Yep, a well balanced series hybrid could get away with as little as 10-15 kW of generating power. ( like the Lotus range extender package )
        You only need 100+ kW when you want a 0-60 mph in under 10 seconds. And you only need that power for those 10 seconds.

        GM however, can not afford to balance the Volt's power systems. It needs to perform well enough for the average American. And the average Tim Taylor does not accept any compromise.
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