2012 Chevrolet Volt - Is it a Real Car? Conclusions
So, here we are. A week's worth of impressions with what is one of the more gutsy offerings from any automaker.
We are left with one last thing to answer - is it a 'real car' when all is taken into account?
There are many ways to tear the Volt apart, to call it a weird science experiment of a car that has no place in the modern automotive landscape. How do you rationalize the weirdness of a compact sedan that costs twice its most comparable sibling in the GM lineup? How do you justify an electric car with a sub-40 mile range and a full gas-fueled power train to cart around as well? How can you excuse a $40k compact Chevrolet that seats just 4?
Well, that is just it.
The Volt is a science experiment. Batteries and motors married to gas propulsion when most cars would be just as happy with just the gas engine. However, if you sat an uninitiated driver behind the wheel - what would they notice? Would they notice anything 'weird' about the experience?
A shifter falls readily to hand and behaves exactly as decades of automotive practice have lead them to expect. Pedals and controls exactly where we've all come to expect them. Quiet operation. Readily available power greater than they'd expect. Fancy displays that suggest high-technology, even if they didn't know what they were suggesting or trying to communicate. They might noice braking that seems a touch off if they were sophisticated enough to notice a slight blip, the barest inconsistency as regenerative braking transitions into pads against disks. But, for all intents and purposes, a 'car'.
Certainly, from a financial standpoint, the Volt is hard to justify at $40k or more unless you can get the federal tax credit. Bonus if happen to live in a state that has a credit of its own that brings the overall purchase down into normal compact sedan territory. GM has also partnered with their old GMAC financing arm (now called Ally Financial) to offer screaming good lease offers as well. Taken into account, the Volt doesn't cost like its MSRP suggests.
Then there is the angle of utility. Only you know if seating for 4 in compact proportions is reasonable, but this is comparable to most compact offerings on the market with any other form of propulsion.
You may not have the option of nightly charging - apartment or condo dwellers, I'm looking at you. In that case, a conventional car is going to be more efficient (a Volt purely on its 1.4 gas engine is not nearly as efficient as several of the comparably sized sedans on sale today.) But, if you have a readily available supply of electricity near your parking - plugging in is no more a burden than grabbing your briefcase or purse from the back seat every night.
But, beyond the few changes to routine - the Volt is built like and drives like a very well turned out compact sedan. A 'Real Car.'
That it just happens to preview where our modern world's march to reward fuel efficiency is very likely taking us is simply another reason to respect how well GM has done with this car. It certainly has me wondering what is coming next (and dreading 'eco' cars just that much less than I did before.)
We are left with one last thing to answer - is it a 'real car' when all is taken into account?
There are many ways to tear the Volt apart, to call it a weird science experiment of a car that has no place in the modern automotive landscape. How do you rationalize the weirdness of a compact sedan that costs twice its most comparable sibling in the GM lineup? How do you justify an electric car with a sub-40 mile range and a full gas-fueled power train to cart around as well? How can you excuse a $40k compact Chevrolet that seats just 4?
Well, that is just it.
A shifter falls readily to hand and behaves exactly as decades of automotive practice have lead them to expect. Pedals and controls exactly where we've all come to expect them. Quiet operation. Readily available power greater than they'd expect. Fancy displays that suggest high-technology, even if they didn't know what they were suggesting or trying to communicate. They might noice braking that seems a touch off if they were sophisticated enough to notice a slight blip, the barest inconsistency as regenerative braking transitions into pads against disks. But, for all intents and purposes, a 'car'.
Certainly, from a financial standpoint, the Volt is hard to justify at $40k or more unless you can get the federal tax credit. Bonus if happen to live in a state that has a credit of its own that brings the overall purchase down into normal compact sedan territory. GM has also partnered with their old GMAC financing arm (now called Ally Financial) to offer screaming good lease offers as well. Taken into account, the Volt doesn't cost like its MSRP suggests.
Then there is the angle of utility. Only you know if seating for 4 in compact proportions is reasonable, but this is comparable to most compact offerings on the market with any other form of propulsion.
But, beyond the few changes to routine - the Volt is built like and drives like a very well turned out compact sedan. A 'Real Car.'
That it just happens to preview where our modern world's march to reward fuel efficiency is very likely taking us is simply another reason to respect how well GM has done with this car. It certainly has me wondering what is coming next (and dreading 'eco' cars just that much less than I did before.)
2012 Chevrolet Volt - Is it a Real Car? Technology Part 2
After the prior post on technology, I realized that there are other pieces to the Volt solution that need to be covered, especially in light of issues recently publicized about the Nissan Leaf and its battery, the Fisker Karma and its recent recall for fires, and for those with a longer memory - the fire in a Volt after a government crash test.
So, let's go even deeper still...
1. Keep air out from under the car. As slippery as any car looks, a large portion of the drag comes from what the air encounters underneath. Suspension parts, fuel tank, exhaust system, and any other parts that hang underneath all create resistance. One way to improve this is by streamlining the underside, but also, you can get big wins by preventing air from flowing under the car.
The Volt takes advantage of the latter with a deep chin spoiler. Made of flexible rubber and missing the ground by just a couple inches - the Volt directs air around rather than under the body. The down-side is that the spoiler does drag on even slight imperfections and contours. Intersections that dip down then back up - you hear it rub. Pulling into driveways or parking lots that slant up from the road - drag again. It will either drive you crazy or you can think of it as a way you have something in common with an exotic sports car.
GM does offer a spoiler with more clearance as an accessory - but you'll have to accept a mileage penalty for letting more air get under the car.
2. Mirrors. They stick out on any car like ears. Catching air that is accelerated by being pushed up by the hood and away by the windshield. They are encountering air moving faster than the car and turbulent to boot. You might notice the Volts aren't smaller but they are held away on wings. This gets them out of the most turbulent air for enhanced aero efficiency. GM reports that they are good for an extra 0.5 miles of range with this design.
3. Sharp rear corners. As important as managing how air flows around the car is how it leaves the car once it has passed through. To make air cleanly break away from the sides, the Volt has sharp corners on the trailing edge of the sides. This makes the air separate rather than swirl around and continue to drag on the body as it passes through. Just further attention to detail that you see on this and soon most other cars as federal mandated mileage increases take effect.
So, let's go even deeper still...
Aerodynamics
It is one thing to make an electric car efficient in storing, turning power into motion, and reclaiming it as well. But, any electric car has to keep an eye on any energy lost that isn't helping keep the car moving. First and foremost, we have energy lost to the air the car moves through. This is why the Volt has the shape it does, but a few tricks are interesting to call out.The Volt takes advantage of the latter with a deep chin spoiler. Made of flexible rubber and missing the ground by just a couple inches - the Volt directs air around rather than under the body. The down-side is that the spoiler does drag on even slight imperfections and contours. Intersections that dip down then back up - you hear it rub. Pulling into driveways or parking lots that slant up from the road - drag again. It will either drive you crazy or you can think of it as a way you have something in common with an exotic sports car.
GM does offer a spoiler with more clearance as an accessory - but you'll have to accept a mileage penalty for letting more air get under the car.
2. Mirrors. They stick out on any car like ears. Catching air that is accelerated by being pushed up by the hood and away by the windshield. They are encountering air moving faster than the car and turbulent to boot. You might notice the Volts aren't smaller but they are held away on wings. This gets them out of the most turbulent air for enhanced aero efficiency. GM reports that they are good for an extra 0.5 miles of range with this design.
Rolling Resistance
Tires not only hold up your car, they provide all the traction needed for accelerating, braking, and cornering. The negative is that they take energy away just to roll. Wizards at the tire companies have worked for years to make 'low rolling resistance' tires that attempt to have all the right amounts of traction with a minimum amount of drag. The Volt is equipped with Goodyear Assurance tires for that reason.Battery technology
Battery packs are new additions to a car. Lithium Ion batteries also have specific needs to have long lives needed in a car that might drive a couple hundred thousand miles. There are things that engineers choose to do or not do that affect the reliability and safety of the batteries and the vehicle occupants.
1. Lifespan of the battery. A Lithium based battery, like we mentioned earlier, doesn't react well to full charges or discharges. GM's answer is to equip the Volt with a larger than needed pack and never fully charge or discharge the cells - extending their range. Another piece to long-life is temperature extremes. A pack like that in a Volt, Leaf, or Fisker Karma do not like getting overly cold or overly hot. A way to control this temperature is to give the pack it's own dedicated climate control system. GM has decided to design in the ability for the Volt to heat or cool its pack to keep it within a healthy temperature range, but that is expensive.
Recently, you might have heard a controversy concerning Nissan Leaf owners and range loss in their cars. While Nissan has ultimately decided that this was due to many of these cars being driven more than the designed for 12k miles per year - meaning that are more than a year into owning them as far as the engineers are concerned (figure that 18k miles would mean that the battery is more like 1.5 years of battery life into its driving).
Also, many of these drivers also live in very hot climates (Arizona, for example). It might be significant to note that the Leaf has a heating system for its battery, but no cooling - depending on air-flow to keep the pack from overheating. This allows the Leaf to come in at a lower cost, but might ultimately end up meaning that Leafs (Leaves?) could take a certain hit in battery life-span. Time will tell.
2. Fire. Some time ago, the US government agency, NHTSA, conducted a crash test of the Volt. It was highly publicized that the Volt caught fire after the crash.
What was not necessarily covered well was that it was well over a week after the crash test when this happened. Also, while NHTSA drains the fuel tanks of all crash test 'victims' the Volt's battery pack was left charged - leaving behind the energy needed to cause a fire. Even so, Chevrolet performed a running change and recalled 8000 Volts to install body reinforcements to prevent any intrusion into the battery pack area that could lead to a fire.
It seems that the fire risk of battery equipped cars isn't unique to the Volt (recently, the Fisker Karma, another extended range electric, also had some bad press when a pair of their cars were lost to fire while in customer hands - though at least one of those was tied to a faulty cooling fan, not the battery pack). Even with thousands of battery powered cars on the road, equipped with unfamiliar technology to many, the fire risk does not appear to be significant compared to 'conventional' cars.
So, the Volt is a high-tech car that has its own challenges that are largely shared with others of its ilk. Something that any owner should keep in mind if considering one of their own.
Next up, our conclusion to our multi-part review of the Chevrolet Volt - Is it a Real Car?
2012 Chevrolet Volt - Is it a Real Car? The Big Drive
The Big Drive:
After spending a few days using the Volt to commute and needing only a small amount of gasoline per day to complete my drives, this left me wondering how things get when you have an even longer drive. How would the Volt behave when leaning heavily on the range-extending gas engine?
In keeping with Volts MO, the first 61.0 miles were on battery capacity (um, what was that about a rated 35 miles in electric again?) and the remainder on gas (182.2). Apparently the missing 0.1 is lost in 'GM Math-land'
While higher speeds on the gas engine were a bit drone-y (due to the higher RPM the engine needs to run at to provide adequate electricity to maintain speed) otherwise the car simply behaves as expected with no obvious downside to running in this mode (though there were no situations where I needed emergency passing power or to climb severe grades beyond the 6-mile/1500 foot elevation gain drive at the end of my daily drives - situations where I might expect to feel that I only had 74hp at my disposal).
I also got a chance to use the Volt's Mountain Mode feature. On a completely flat battery and 15 or so minutes before heading up the last climb to home, I switched to that mode by pressing the 'Driving Mode' button three times. The Mountain Mode attempts to achieve or maintain 40% charge in the battery. If you are already at or above that charge level - the engine does not turn on. If you are below that level, the engine will start and attempt to put charge into the battery as well as propelling the car to get you back up to 40%.
In this case, the engine, which was running most of the time anyway turned on, at high rpm, and stayed on (see my prior observation about drone). In this mode, the battery never showed a charge during this time, leaving you largely in the dark as to what it is doing. However, once I turned Mountain Mode off right as the climb started, the engine switched off and it never turned on during the entire climb.
In other words, if you are willing to plan climbs, even on high-mile/range-extended days, you will appreciate the work this mode does to prepare the Volt for the more strenuous loads.
So, after what is significantly more than the battery-only range, what do the numbers look like?
Gas in the tank was still worth $3.699 a gallon
Electricity was still $1.04, total, for the 12kWh (amount estimated to recharge).
I burned 4.39 gallons today, for 41.45 mpg during the actual miles driven under gasoline power (the 55.3 mpg listed above is because the Volt calculates based on total miles vs the gasoline burned).
$16.24 in fuel and $1.04 in electricity for a total of $17.28 to do today's driving.
Compared again to ye olde mid-size sedan I normally spend seat time in...
It gets 25 mpg in my driving. 9.732 gallons would have been burned. $36.00 in gas.
So, I saved $18.72 in energy expenses.
You start to see what we might have expected...savings are not linear with miles traveled since your biggest wins are when you stick to the cheapest energy per mile - the kWh living in the battery pack.
However, there is another way to look at this (one that GM hopes consumers will think about)... if I were in a Nissan Leaf (a car that would handle the day-to-day commuting just fine) for this drive, I'd have been sleeping in it that night waiting for the battery to charge somewhere less than half the way through the day's driving. This is the usage case for which the Volt seems designed.
Next up, more talk about the Volt's underlying technology and how it compares against competitors.
2012 Chevrolet Volt - Is it a Real Car? Technology
While it is relatively straightforward to grok how a conventional car works (fuel burns, moves pistons, this drives a car forward through gears and drive shafts and axles...the Volt is a touch harder if only because of its different technique.
So, we've talked at a high level about how it works, now lets go a bit deeper.
For well over 100 years, cars have been powered almost exclusively by burning of fossil fuel. This centers on capturing the energy of burning fuel into mechanical motion that is transferred through transmissions, drive shafts, axles, to wheels.
Returning to a stop is accomplished by using plates (brake calipers), covered in a friction material (brake pads), that rub against disks or drums to slow the vehicle by turning that motion into heat.
The rub here is that once fuel is burned, it quickly escapes as waste heat (radiated from the engine having done nothing to move the car or exiting through the exhaust system having only helped in the case of a turbo-charged car that reclaims that exhaust energy to boost the engine's power) or becomes motion that ultimately dies an unceremonious death as heat through the brakes or other friction (with the air, with the road through tires, or in countless other places where that energy passes on its way to move the car along).
You can use the word 'efficiency' to refer to how much work is done (to move the car from point A to point B) by that burned fuel before it becomes heat in one of those many forms and is lost.
So, all of the efforts to achieve 'high efficiency' in cars are exercises in increasing efficiency by doing something to get more motion out of the energy put into the system.
Techniques that can be used include reducing friction. Aerodynamics reduce the friction with the air. Low rolling resistance tires reduce friction with the road. Optimizations in the moving parts of a car can reduce loss of energy through friction, either through improved lubrication or changing the types of connections to ones that might be more expensive, but lose less energy to friction.
Vehicles that carry batteries and electric motors of any kind (hybrids, full electrics, and cars like the Volt) also carry out another trick - they reclaim energy of motion back into the battery through a technique known as regenerative braking. Electric motors that can propel the car reverse their function and become generators powered by the motion of the car itself. Turning that motion into electricity slows the car. The electricity is stored in batteries that then power the motors again to re-propel the car later.
So, that covers some of the techniques generally used today to improve efficiency but how does a Volt work?
A Volt is not exactly as a hybrid like a Toyota Prius nor a pure battery electric vehicle like a Nissan Leaf - rather it can be thought of as an electric car with an on-board generator powered by gasoline.
So, how is that different than a hybrid like the Prius?
A hybrid uses a gasoline engine and electric motor/battery to propel the car. At low speeds, the electric motor can propel the car by itself, but at moderate to high speeds (or when significant acceleration is needed), the gasoline engine must be engaged to assist. The efficiency gains of a hybrid occur mainly in stop and go driving when the regenerative braking and low speed electric operation combine to reclaim energy and use it again, reducing the amount of fuel that has to be burned in slow-speed operation (this also points to why hybrids typically have better mileage in city driving than on the highway - the electric propulsion either doesn't come into play on the highway or is insignificant).
Also, there is added complexity that comes from having the gas engine and electric motor operating simultaneously to move the car along - both have to supply power to a common transmission that then combines the inputs and supplies a single output force to the drive wheels. Obviously this works, but it is complex.
A Volt, by contrast, provides drive power to the wheels through a pair of electric motors. They get their electric power from a battery pack or from the generator driven by the gas engine. In normal operation, when there is power in the battery pack, all the electricity needed to drive the Volt is coming from its battery and the gas engine does not run. In my testing, I was often able to go 50+ miles (arguably, my first 8+ miles are down a long mountain grade, so that is why my range is higher than the EPA rated 35 miles) before the gas engine needed to start. If my daily drive was less than that 50 miles, I would not burn any gasoline at all.
So, it is like an electric car like a Nissan Leaf? Not exactly.
In a battery-only electric car like the Leaf, you can only go as far as the energy in the battery can sustain you. Once you have run out of electricity, you must re-charge. The downfall of this is the recharge time of a modern battery. Even with higher voltage 240V (level-2) charging, it will take hours to 'refill' the battery. Compare this against the sub-10 minute refill time of a gasoline powered car and you see that an electric is often limited to commuter car duty, and why some people have a problem buying into this technology - even if it would actually meet their needs.
In a Volt, once the battery is depleted, a gas engine (1.4 liter 4-cylinder that runs on premium fuel) starts and runs an electrical generator. Power from this generator now becomes the input to the electric motors that propel the car. Since the engine/generator pair only put out the equivalent of 74hp, less than half the 150hp combined output of the electric motors, the Volt is actually slower in this mode than when the battery pack is being used. However, I found that even in this mode, the Volt could sustain 50-55mph up mountain grades and interstate speeds were no problem.
This combination of battery with generator fall-back give the Volt a real-world advantage over both a traditional hybrid and a full-electric car. Efficiency in normal day-to-day driving is significantly better than a hybrid and for the occasional drive that exceeds your electric-only range, you just continue on as you always have in gasoline-powered cars of old.
However, this dual-power trick the Volt attempts isn't without its own complexities. First of all, you are carrying both the electric propulsion items (motors, electronics, batteries) as well as all the parts you know from a conventional gasoline powered car (gas tank, engine, radiator). All of this brings weight and complexity (though not really more than you would get with a hybrid that also has a dual-power system).
Secondly, because of the expected short time the gas engine would be used in day-to-day driving, the Volt carries only a small (9.3 gallons) tank of fuel. This provides a somewhat shorter range than a conventional gas-powered car. And, even with this small a tank, there needs to be logic built into the Volt that occasionally runs the engine to burn off fuel before it becomes 'stale' in the tank. The tank is also lightly pressurized to extend the life of the gasoline even further.
Finally, there is the complexity that comes with carrying batteries. The Volt does have a fairly large battery pack. This pack is made of 288 individual lithium-ion cells similar to those found in modern portable electronics. The battery in a Volt has a total capacity of 16kWh, though you may have noticed that I only saw 10kWh of energy before the car switched to gas engine/range extended mode. This is because of an interesting little secret of lithium-ion batteries. Li-Ion really hates to be fully charged or fully discharged. Putting in as much power as it can hold or pulling all the power completely out reduces its lifespan greatly (which is why the battery in your cell phone dies a couple years after you bought it - portable electronics use the full capacity of the battery.) In an automotive application, a battery needs to live closer to 10 years. In order to get there, GM designed the Volt's battery to only use the middle of its capacity - they never fully charge or discharge the pack and, as a result, expect 70-90% of its new capacity to be retained after 10 years. Time will tell if this actually ends up to be true.
One last piece of the efficiency game, the regenerative braking trick used by hybrids, etc., is also used here. So, slowing a Volt will put power back into the battery for later use. The 'gear' selector has settings for Park, Reverse, Neutral, Drive, and Low - Drive and Low are different only in the amount of regenerative braking they provide - Low is useful in steep grades and in stop and go traffic where more pronounced slowing is nice to have. In fact, during stop-and-go driving, I could often use Low to slow the car all the way down to 3-5 mph before touching the brake pedal. This technique, which was far from 'hypermiling', maximized the energy I reclaimed.
So, as you can see, the Volt uses a combination of techniques and technologies to provide yet another take on the 'efficient car' game. It's downfalls are complexity, weight and cost of carrying dual power sources, and - strangely enough - the difficulty in explaining how this is different than a battery powered car or a hybrid. Call it an electric and that doesn't seem quite right. Call it a hybrid and that doesn't capture it either. Call it, like GM does, a Range-Extended Electric Vehicle - and you likely will get blank stares. But at least you know how it works now.
Next up, we cover a very busy day of driving and get back into how it is to live with in real-world use...
So, we've talked at a high level about how it works, now lets go a bit deeper.
Where we have been:
For well over 100 years, cars have been powered almost exclusively by burning of fossil fuel. This centers on capturing the energy of burning fuel into mechanical motion that is transferred through transmissions, drive shafts, axles, to wheels.
Returning to a stop is accomplished by using plates (brake calipers), covered in a friction material (brake pads), that rub against disks or drums to slow the vehicle by turning that motion into heat.
The rub here is that once fuel is burned, it quickly escapes as waste heat (radiated from the engine having done nothing to move the car or exiting through the exhaust system having only helped in the case of a turbo-charged car that reclaims that exhaust energy to boost the engine's power) or becomes motion that ultimately dies an unceremonious death as heat through the brakes or other friction (with the air, with the road through tires, or in countless other places where that energy passes on its way to move the car along).
Where we are going:
You can use the word 'efficiency' to refer to how much work is done (to move the car from point A to point B) by that burned fuel before it becomes heat in one of those many forms and is lost.
So, all of the efforts to achieve 'high efficiency' in cars are exercises in increasing efficiency by doing something to get more motion out of the energy put into the system.
Techniques that can be used include reducing friction. Aerodynamics reduce the friction with the air. Low rolling resistance tires reduce friction with the road. Optimizations in the moving parts of a car can reduce loss of energy through friction, either through improved lubrication or changing the types of connections to ones that might be more expensive, but lose less energy to friction.
Vehicles that carry batteries and electric motors of any kind (hybrids, full electrics, and cars like the Volt) also carry out another trick - they reclaim energy of motion back into the battery through a technique known as regenerative braking. Electric motors that can propel the car reverse their function and become generators powered by the motion of the car itself. Turning that motion into electricity slows the car. The electricity is stored in batteries that then power the motors again to re-propel the car later.
So, that covers some of the techniques generally used today to improve efficiency but how does a Volt work?
A Volt is not exactly as a hybrid like a Toyota Prius nor a pure battery electric vehicle like a Nissan Leaf - rather it can be thought of as an electric car with an on-board generator powered by gasoline.
So, how is that different than a hybrid like the Prius?
A hybrid uses a gasoline engine and electric motor/battery to propel the car. At low speeds, the electric motor can propel the car by itself, but at moderate to high speeds (or when significant acceleration is needed), the gasoline engine must be engaged to assist. The efficiency gains of a hybrid occur mainly in stop and go driving when the regenerative braking and low speed electric operation combine to reclaim energy and use it again, reducing the amount of fuel that has to be burned in slow-speed operation (this also points to why hybrids typically have better mileage in city driving than on the highway - the electric propulsion either doesn't come into play on the highway or is insignificant).
Also, there is added complexity that comes from having the gas engine and electric motor operating simultaneously to move the car along - both have to supply power to a common transmission that then combines the inputs and supplies a single output force to the drive wheels. Obviously this works, but it is complex.
 |
| Volt's 1.4l Gas engine (front and center) and the brains of its electric drive (to the right). Orange high-capacity power cables let the energy flow to where it's needed. |
So, it is like an electric car like a Nissan Leaf? Not exactly.
In a battery-only electric car like the Leaf, you can only go as far as the energy in the battery can sustain you. Once you have run out of electricity, you must re-charge. The downfall of this is the recharge time of a modern battery. Even with higher voltage 240V (level-2) charging, it will take hours to 'refill' the battery. Compare this against the sub-10 minute refill time of a gasoline powered car and you see that an electric is often limited to commuter car duty, and why some people have a problem buying into this technology - even if it would actually meet their needs.
In a Volt, once the battery is depleted, a gas engine (1.4 liter 4-cylinder that runs on premium fuel) starts and runs an electrical generator. Power from this generator now becomes the input to the electric motors that propel the car. Since the engine/generator pair only put out the equivalent of 74hp, less than half the 150hp combined output of the electric motors, the Volt is actually slower in this mode than when the battery pack is being used. However, I found that even in this mode, the Volt could sustain 50-55mph up mountain grades and interstate speeds were no problem.
This combination of battery with generator fall-back give the Volt a real-world advantage over both a traditional hybrid and a full-electric car. Efficiency in normal day-to-day driving is significantly better than a hybrid and for the occasional drive that exceeds your electric-only range, you just continue on as you always have in gasoline-powered cars of old.
However, this dual-power trick the Volt attempts isn't without its own complexities. First of all, you are carrying both the electric propulsion items (motors, electronics, batteries) as well as all the parts you know from a conventional gasoline powered car (gas tank, engine, radiator). All of this brings weight and complexity (though not really more than you would get with a hybrid that also has a dual-power system).
Secondly, because of the expected short time the gas engine would be used in day-to-day driving, the Volt carries only a small (9.3 gallons) tank of fuel. This provides a somewhat shorter range than a conventional gas-powered car. And, even with this small a tank, there needs to be logic built into the Volt that occasionally runs the engine to burn off fuel before it becomes 'stale' in the tank. The tank is also lightly pressurized to extend the life of the gasoline even further.
Finally, there is the complexity that comes with carrying batteries. The Volt does have a fairly large battery pack. This pack is made of 288 individual lithium-ion cells similar to those found in modern portable electronics. The battery in a Volt has a total capacity of 16kWh, though you may have noticed that I only saw 10kWh of energy before the car switched to gas engine/range extended mode. This is because of an interesting little secret of lithium-ion batteries. Li-Ion really hates to be fully charged or fully discharged. Putting in as much power as it can hold or pulling all the power completely out reduces its lifespan greatly (which is why the battery in your cell phone dies a couple years after you bought it - portable electronics use the full capacity of the battery.) In an automotive application, a battery needs to live closer to 10 years. In order to get there, GM designed the Volt's battery to only use the middle of its capacity - they never fully charge or discharge the pack and, as a result, expect 70-90% of its new capacity to be retained after 10 years. Time will tell if this actually ends up to be true.
One last piece of the efficiency game, the regenerative braking trick used by hybrids, etc., is also used here. So, slowing a Volt will put power back into the battery for later use. The 'gear' selector has settings for Park, Reverse, Neutral, Drive, and Low - Drive and Low are different only in the amount of regenerative braking they provide - Low is useful in steep grades and in stop and go traffic where more pronounced slowing is nice to have. In fact, during stop-and-go driving, I could often use Low to slow the car all the way down to 3-5 mph before touching the brake pedal. This technique, which was far from 'hypermiling', maximized the energy I reclaimed.
So, as you can see, the Volt uses a combination of techniques and technologies to provide yet another take on the 'efficient car' game. It's downfalls are complexity, weight and cost of carrying dual power sources, and - strangely enough - the difficulty in explaining how this is different than a battery powered car or a hybrid. Call it an electric and that doesn't seem quite right. Call it a hybrid and that doesn't capture it either. Call it, like GM does, a Range-Extended Electric Vehicle - and you likely will get blank stares. But at least you know how it works now.
Next up, we cover a very busy day of driving and get back into how it is to live with in real-world use...
2012 Chevrolet Volt - Is it a Real Car? Trivia
A little bit of Volt trivia, in light of it's green car mission. Specifically CO2 Emissions.
The numbers I was able to find shows that Colorado's electricity averages 1.93 lb /kWh of CO2 emitted. This is actually worse than the national average which is about 1.3-ish.
I had to do some digging to get CO2 emissions for gasoline powered cars. I found you are getting 20lbs of CO2 per gallon, 2 gallons for a 50 mile drive in my 25mpg car, so 40 lbs for the same distance. (data and explanation of how you end up with more than the weight of a gallon of gasoline from http://www.fueleconomy.gov/feg/co2.shtml )
So, figuring 12kWh is getting me about 50 miles - that maps to 23.16 lb of CO2 for that 50 miles (12kWH * 1.93 lb/kWH)
So, for _me_ (my drive, in my state) it appears CO2 emissions would be cut almost in half.
Also note, this does _not_ take into account things like emissions of any other pollutant, mainly from manufacturing the Volt (or any other new car). I'm just presenting this as a data point, nothing more.
More tomorrow.
2012 Chevrolet Volt - Is it a Real Car? Initial Impressions
DAY 1 Driving Impressions:
Let's give a bit of context to this set of pics below (taken after my first drive to work after charging fully):
I charged fully, overnight, from 120V using the Volt's included power cord (that normally lives under the cargo area floor). It took 10 hours to go from a complete discharged battery to full. Doing so resets the stats of the center display's energy usage stats. Normally this display shows the miles since last recharge divided by electric and gasoline powered miles as well as kWh used (the Volt has a 16kWh batter pack, of which 10.4kWh is usable - more on that in a bit) and gallons used. Also a measure of overall, lifetime mpg is shown (this is simply total miles divided by total gallons and ignores any sort of electricity to gasoline conversion like the EPA uses to generate their MPGe numbers.
Starting out, the car showed 39 miles of projected electric range. However, given my 8 mile downhill drive at the beginning of my commute, it used regenerative braking (using the electric motors as generators to turn energy you'd burn off as heat through the brakes back into electricity) to put even more charge into the battery than allowed by having it plugged-in (the car does some strange things with the battery pack to protect its lifespan, essentially leaving a fudge-factor at the charged and discharged end for things like 'a place to put regen energy when the battery shows full' and also 'a place to get reserve passing power when the battery shows empty' I've experienced both extremes in the course of less than 24 hours.
Tangent #1 - on the prior day's up-hill drive with a stated 'empty' battery, I did experience what felt like a kick-down to passing gear at one point on the hill. This apparently was the Volt deciding to let me tap into the reserve in the battery. However, the reserve was not enough to get me home before giving a warning message of 'reduced power' and I ended up losing about 10mph in the last 2 miles of the climb. This happened over the course of an 8-mile drive with 1500' elevation gain. Maximum speed ended up in this stress test as 50-55mph.
Tangent #2 - On the downhill side, I put the car into L ('mode') to increase the regenerative braking. This did successfully keep the downhill speed under control until it filled the reserve capacity of the battery. So, about 2/3 of the way down the hill, I went from having a feel of 'engine-braking' through the regeneration pulling off speed as electricity into the battery to then feeling like I was coasting (and then need to use the actual brakes to keep speed down).In both cases, you have to understand what the car is doing with energy management to not be caught off-guard by the behavior. I wonder if 'average' Volt buyers are going to understand what is going on - at least the first time.
But, I digress, the stated range on electric got as high as 50 miles by the time I got down to the bottom of that same 1500' elevation change and had pulled every bit of extra energy from the drop and stored it into the battery pack's reserve capacity.
I topped off the tank (premium fuel required), to have a good baseline, and it took about 1.5 gallons to have the tank full - we'll see after a week how much gas I really burn.
We'll just ignore the pie-in-the-sky figure of 250+ mpg for the trip for now.
The rest of the day saw a trip across town in Boulder, a drive up and through Longmont, then back to up the hill for the 1500 ft elevation gain to home.
I was able to make all but the last 7.4 miles of today's driving on electric. As you can see in the attached end of day energy use stats, I managed 52.5 miles of electric driving (not bad for a car that is rated at 35 miles of electric range - even if you figure the first 10 miles were essentially free as they were all down-hill).
I didn't use the Volt's 'mountain mode' to prepare for the climb. Mountain mode attempts to keep 40% charge in the battery. It will run the range extender at high-speed to charge the battery to this level if you are below, or do nothing at all if you are already at that charge level. This is to preserve some capacity for hill-climbing and would have been a good choice.
I ran out of juice only a couple miles right before the climbing beings in earnest and this time did not run into the dreaded 'reduced power' mode. However, this is largely due to keeping my speeds down to the 55mph that I was limited to in the reduced power mode the night before. Even so, the gas engine was revving quite high to generate all the power it could to keep things moving along (the generator is capable of 74hp - which is only slightly less than half the 150hp the electric drive motors can consume, which is why hill-climbing in this mode is not slower than if you have a charged battery.
Tomorrow will not have the extra errands thrown in, so I might be able to make the full drive on battery power - we'll see.
@ 8.7-ish cents per kWh for me, that means a total cost of driving today of $2.35.
Figuring the same drive in my comparably sized sedan @ 25mpg, I would have burned $8.85 of gas.
So, the Volt paid for my lunch today. ;-)
More tomorrow.
2012 Chevrolet Volt - Is it a Real Car? Introduction
Quick, how many automotive segments can you name? How do you even define the segments? Cars, trucks, SUVs, vans? How about sub-divisions between segments (crossovers anyone?). What about sizes within a segment? However you slice it, we are inundated with choices of cars and trucks and everything in between. In a world with such a wide array of options, imagine introducing a model that is something completely new. That is the daunting task facing GM with its Chevrolet Volt electric. They have the multiple tasks of introducing a new model as well as educating consumers about what makes is tick and why they should care.
The Volt is GM's latest foray into the electric car market. To the most jaded, it could be called a plug-in hybrid because in addition to electric drive it also is equipped with a gasoline engine. However, to the optimist as well as the marketers at GM, it can be (and likely, should be) viewed as an electric car that doesn't limit you to the range of its battery pack in per-day driving.
So, first, the requisite background. What has led GM, a company largely known for their trucks and SUVs, to bring to market this unique take on the electric car? And, what is it that makes this a unique electric and not just another hybrid?
The real beginning of the Volt owes a lot to the hire of Bob Lutz by GM in 2001. While Mr. Lutz is known for shepherding development of cars such as the Viper and the big-rig inspired Ram truck (while at Chrysler in the 90's), part of what he did while working at GM was see a perception problem towards GM (especially compared to their closest competitor, Toyota).
Unlike GM's previous electric, the EV1 (leased in California and Arizona in the late 1990's), the Volt enhanced it's electric power-train with an on-board gasoline powered generator. The drive wheels are powered by electric motors, but once the battery was exhausted, the 'range extender' would start, running a generator that would then provide the electricity. In this way, the Volt concept would be able to run on battery power for most day-to-day driving without the danger of leaving an owner stranded and in need of an hours-long re-charge to get back on the road.
This solution acts as a bridge between a future of fast-charge/high-capacity batteries by allowing the Volt to run on pure electricity for the first 40 miles but also allowing trips of practically any distance beyond on gasoline. Need to drive back and forth to work? Battery will likely get the job done. Need to drive to grandma's across a couple states? The Volt has you covered there as well.
There is a certain engineering brilliance in the concept - provide electric-only driving for 80% of the world's commuters without the electric having to be a 'third car' in the garage. The other benefit is in allowing a smaller battery pack than any electric that has to provide all-day usability on a single charge (dual benefit due to the high cost of lithium-ion batteries and their long recharge times that only get longer with larger capacity).
Almost 2 years later, in September 2008, Chevrolet debuted the production version of the Volt. It was obvious from the radical styling change the Chevrolet was caught somewhat flat-footed by the positive response to the original concept. Changes had to be made to the shape of the car to even approach the promised 40 mile electric range (and even then, the best the engineers could do was 35 miles) through improved aerodynamics. Another surprising miss of the production car vs the concept was in MSRP. Where the concept was expected to come in in the upper-20k range (a projection tossed out during the concept's debut by Bob Lutz based on the cost of a comparable compact sedan + $8000 for the advanced battery pack), the production car ended up coming in at $40k, though with a $7500 federal tax credit it is down in the low $30k range. The cost over-run was another victim of efficiency needed by a car that runs everything off of battery capacity - items as varied as the stereo to the wiper motors had to be designed from scratch with an eye toward energy efficiency.
So, does the Volt, a car that missed by marginal amounts the promises made by GM during the concepts debut, still live up to the promise of this unique take on the electric car?
Subsequent posts here UOWCars.com will show what we found out. Stay tuned.
Chevy Volt approved for production!
I'm somewhat an oddity. I am a hard-core automotive enthusiast - but also incredibly conscious of the ecological impact of my hobby.As that, I am seriously stoked about the Chevy Volt concept.
If you've been under a rock for the last few months, the Volt was the first implementation of GM's E-Flex concept.
In essence, picture the E-Flex (and the Volt) as an electric car. Using cutting edge Li-Ion battery technology (similar to what you'd find in consumer electronics like laptops), the vehicle allows for range of around 40 miles on a charge and the ability to charge in a few hours from standard household current.
While 40 miles would not be enough to entice most folks, GM gets around this by putting a highly efficient secondary power source on board to help charge the batteries and produce electricity for times when the batteries are not sufficient. This provides flexible choices for the secondary power source, from gasoline engines, E85 powered engines, or even fuel cells.
With the secondary source, you get the ability to drive 40 miles on pure electricity while not having to worry that, if something unforeseen comes up, you might not be able to complete your trip and make it home (a major limitation of previous electric vehicles).
Given the optimized size of the secondary power source, you should see fuel economy numbers of at least 50-60mpg while seeing many owners never having to fuel the vehicle for months at a time and effective mileage in the hundreds of miles per gallon. And, unlike most previous electric vehicles, a Volt would have the utility and range of a conventional car (and the ability to refuel to extend your trip) - while giving you extreme fuel savings in your average day-to-day driving.
While this system has created quite a buzz, most (myself included) have been somewhat cautious about warnings from GM that battery technology might not allow the concept to come to market for some time.
Now, Automotive News (via Leftlane News) has reported that GM has officially green-lighted Volt for production. It will be an off-shoot of the Delta II chassis that will also serve as the basis for the next Chevy Cobalt as well as the next Saturn Astra (not the model that comes to market this fall).
Also of interest is that GM expects to make the production Volt available in 2010 and will offer a choice of either a gasoline or fuel cell secondary power source.
I'll be keeping a very close eye on this one and might consider it as one of my choices for my daily driver (while keeping a nice sports car on the side for my enthusiast 'needs').
Read about it at:
Leftlane News: Shocking! Volt Production by 2010?