Jun 26, 2008
2009 Smart Fortwo Test Drive: With Li-Ion Smart Two Years Out, European Eco Trifecta Gives Preview
SEVILLE, Spain — With prices starting at $11,590 for the basic Pure model, the Smart Fortwo is one of the most economical rides in the States—even if it's a long way from being the cheapest. The tiny, 70-hp Smart car was introduced in the United States this January and has sold like wildfire through Penske Automotive Group dealers. It's good for 90 mph and 0-60 mph times around 12.8 seconds. No, it's not going to embarrass your neighbor's AMG—unless you're competing for fuel economy, that is. The Smart delivered a rather frugal 33 mpg city and 41 mpg highway in the 2008 EPA tests. And that's not good enough, says Smart's parents at Mercedes-Benz, which recently unveiled a trio of even more economical Smart cars. We recently drove all three over here across the pond.
And maybe even better news: Mercedes-Benz's head honcho Dieter Zetsche announced this week that the German company will sell an electric Smart for 2010, along with an electric Mercedes-branded vehicle. It's likely that both will use lithium-ion battery technology. But 2010 seems like an awfully long time to wait these days, so we slid behind the wheel of the first-gen Smart EVs—part of a research project in conjunction with British electronic specialists Zytek. Closer to reality is the new the micro-hybrid-drive gasoline Smart with a stop/start system. It will be introduced into all gasoline Smart models with the exception of the tuned-up Brabus version (Europe only), beginning in September. The new Smart diesel will be introduced in Europe this year, but probably won't make the jump over to the States. —Andrew English
Based on the previous Smart model, over 100 of these battery-electric vehicles have been converted in Fradley, Staffordshire and are on test all over the UK. The 30kW/41hp brushless, liquid-cooled, DC motor is designed and built by Zytek, with the motor, inverter and controlling electronics in one housing. All that fits onto the conventional engine's three mounting points. The conventional transmission is locked into second gear, as there's no need for more given the torque delivery characteristics and 12,000-rpm peak operating speed of the electric motor. The high-temperature salt battery is a natrium-nickel chloride unit made by MES-DEA of Switzerland, which is mounted under the floor where the fuel tank sits in a conventional Smart.
Top speed is 75 mph and the 0-37 mph acceleration is quoted at 5.7sec, about the same as that achievable with the petrol Smart. Maximum range (with very gentle driving) is 70 miles. But you need to avoid fast acceleration and hard braking to achieve this. Brake gently, and the kinetic energy is recycled as electricity; brake hard, and the friction linings are brought into play, wasting energy as useless heat. The battery can be recharged via a conventional British 220/240 volt socket, and it takes eight hours for a full charge from empty. But it takes three and a half hours to recoup from 30 to 80 percent of its capacity. On the European Combined cycle, power consumption is about 12kW/hrs per 62 miles and at current values this costs around 0.02 Euros per kilometre ($0.05 per mile). The battery can be recharged at least 1,000 times, which in normal use gives a life of about 10 years. Currently, British firms are paying about $750 per month in leasing costs to use these little cars—plus the recharging costs, of course.
Inside, the EV Smart is almost identical to its gas sister, although there's only a two-position gearlever (Drive and Reverse). The charge-level indicator is in the middle of the instrument binnacle. The battery remains hot all the time, so starting takes no more than five seconds after a systems check. Then you simply press the throttle and go.
The little car is quick off the mark as the traction motor delivers all of its 88.5 lb.-ft. of torque to the rear wheels from zero revs. As a result, it's difficult to maneuver in tight places as the car tends to surge forward. You need to keep your left foot covering the brake. You also need to keep your hand on the horn, as pedestrians don't hear the little Smart coming and will step off the sidewalk right into its path—this is going to be an ongoing problem for electric vehicles in built-up areas.
The standard Smart is hardly the acme of ride quality, and with 242 pounds more weight, the electric version is worse. On smooth roads, this electric-powered two seater is fine, but the individual wheel rates are high and the wheels crash into pot holes and sleeping policeman. It's an experience best forgotten. In addition, the electricity-powered air conditioning system is, frankly, a joke.
On suburban roads, though, the electric Smart is a hoot. The limited top speed never seems to be a problem, and there's always enough instant surge to go to for the gaps. Of course, the emissions-free operation only applies to the tail pipe, and fans of pure battery technology always seem to have a blind spot about what lies beyond the plug and where the electricity comes from, but for polluted city centers, the advantages of this silent-running bollide are obvious—even if you end up driving around pedestrians like cones on a slalom course.
In the European Combined economy tests, the standard Smart delivers 50.0 mpg (US) and emits just 116 grams of carbon dioxide on the EU combined cycle. Crikey, is it possible to save more fuel than that? Apparently so. Mercedes is claiming the Smart fortwo CDI's 799cc three-cylinder engine is the world's smallest direct-injection diesel, and that the CDI Smart is the world's most economical series production vehicle. It's also the noisiest.
Compared to the previous oil-burning Smart, this new model has common-rail fuel injection at higher pressures (up to 23,200 psi), new seven-hole fuel injectors and a particulate filter that captures 40 percent of particulate emissions. Power and torque are up 10 percent to 44 horsepower and 81 lb-ft of torque respectively. Mercedes says it will deliver 71.3mpg (US) and emit just 88g/km in the EU Combined cycle, which comfortably puts it at the forefront of any list of production economy cars. In fact this little car can do 621 miles on a brimmed tank, enough to travel the 1,200 miles between the farthest points on mainland Britain with just one tank fill.
But there's a hitch.
You'll need earplugs. The car, particularly after a cold start, sounds like a cement mixer on methanphetamine. That's from the sidewalk. From inside, the well-insulated cabin is more tolerable. The noise isn't the only disadvantage: top speed is 84mph and 0-62 mph takes nearly 20 seconds. So the diesel Smart isn't going to set the world alight. But for off-the-line bursts, it doesn't feel too bad.
The bête noir of the Smart range has always been its automated five-speed gearbox. While this new model is better, the transmission still blunts the performance by taking so long to swap ratios and occasionally disengaging drive for seconds at a time. You see the traffic gaps open, you bury your right foot and before the car has done anything, the gap closes again it's very frustrating. The Obox is also programmed to rev out towards the 4,000 rpm redline more strongly than suits the engine's torque curve. On occasions it might be better to short shift manually and let the torque do the work. In the end, however, you do learn to make reasonable progress in the diesel Smart by never lifting off, looking as far down the road as possible and anticipating traffic flows to avoid using the brakes.
This latest-model Smart is vastly improved over its predecessor, which was never sold in the US. The trunk has a proper external release, the door mirrors are now big enough to let you spot stuff smaller than a truck behind you and the facia is better made and less toy like. The cabin is more than big enough for two large adults and the trunk will take a couple of small suitcases. The car is also a great deal more stable at freeway speeds, although it still feels top heavy in corners and the brakes are overly sharp. The two-seat cabin also restricts its practicality and makes this something of an urban eco toy for the wealthy middle classes and their nannies. When we get the diesel here in Britain, it will cost about $1,300 more than the standard gasoline model. And unfortunately, we'll not get the new start/stop function that comes to all gas models this September.
You do suffer for the diesel and not just in the sticker price. It's slower, a lot less refined and downright noisy. The upside is the fuel consumption. Over here, diesel costs about $10 a (US) gallon at the moment. A diesel Smart returning this sort of fuel economy is pretty much immune from the effects of the oil-price crisis, which leaves you lots of spare money to buy a nice pair of Bose noise-canceling headphones for when you're in the car—or a high-tech hearing aid for when you leave it.
The Micro Hybrid Drive
The Micro Hybrid Drive (MHD) isn't a hybrid in the accepted sense of the word. The drive doesn't "drive" the car, and doesn't power the air conditioning. This "hybrid" unit is a beefed-up, belt-driven alternator/starter, which simply powers the stop/start function by recharging the battery on over-run and restarting the car quickly. The 70 horsepower, one-liter gas engine cuts out as the car rolls to a stop at under 5mph. And it automatically starts again as soon as you take your foot off the brake pedal.
It's a simple system that has a big fuel consumption benefit. Mercedes reckons the MHD Smart will return 54.7 mpg (US) in the EU Combined cycle, which is an eight percent improvement. Fuel savings could be as high as 19 percent in crowded city streets. In use, it's almost pain-free. Restarting involves a little more noise and vibration than the equivalent system on BMW's bigger diesel MINI. This is not such a bad thing, however, as there is at least the confidence that the engine is actually running when the lights change and you put your foot on the throttle.
The system will be fitted to all non-diesel Smarts from September this year, although the company is vague as to whether US Smarts will get the drive immediately.
We hope they do: it seems like such an eco no brainer. Just imagine if every engine in Los Angeles was stopped as soon as its speed dropped below 5 mph.
What would that do for fuel consumption? Or air-born particulate emissions?
How much sweeter the air would be, how much quieter the sidewalk