Sunday, February 1, 2015

Driving slowly

The thrill of driving a powerful gasoline powered car hard is sensational, from the forces exerted upon you to the sound effects emitting from the engine.  I should know, having owned a number of performance cars over the past three decades.  From my 1982 Mercury Capri with its powerful 5.0 liter V8, to the 1987 BMW 325i with its five-speed gearbox, to the 2001 Dodge Dakota Quad Cab with its pavement shredding V8 (coupled with trailer gearing), to my 2005 VW GTI turbo.  All of these cars are great fun to drive up hills, roar down the interstate, and pull away from a traffic light with great aplomb.  They also share the same drawback: trying to move slowly is a painful mix of lurching and clutch wearing strain.  Switching to an automatic transmission does little to resolve this either, as I have experienced in a Passat, an Audi A4, and a Toyota Corolla.  The fact is, gasoline powered cars were never designed to be driven slowly.

My (former) 1982 Mercury Capri in its new garage
Who needs to drive slowly?  Consider these situations …  You are stuck on I-405 approaching Century Blvd.  Finally, the traffic inches forward (literally, about 8 feet).  Or, you need to back into a gently sloping driveway.  Or, while visiting San Francisco, you have to stop at a stop sign on a 25% grade.  Or, you need to back your car into your underground parking space around the concrete pillar.  Too much gas, and you could slam your car into something not-soft.  Too little, and you could stall, changing your direction of travel unexpectedly.  Of all of these, the most annoying is trying to follow slow-moving traffic on the freeway that seems to lurch along.

I never expected that the electric motor would solve these issues.  The instant-on torque of the electric motor and the ability to deliver very precise amounts of current allow the electric car to thrive in these slow-motion environments.  In my Mitsubishi, the (software) engineers who programmed the motor controller were able to simulate the gasoline engine’s inability to stand still while in gear by allowing a small amount of current to flow to the motor while at “idle”.  The software does a spectacular job.  While backing into a gently upward sloping driveway, I was able to remove my foot from the “gas pedal” and the car backed itself up the driveway at about two to three MPH, allowing me to position the car deftly.  Another (software) engineering feat is just how smoothly the car transitions from standing still to a full run.  There is no jerk at all, and you can control the speed as slowly as you need, down to one or two MPH.  This came in very handy while inching into the parking lot for the electric car rally and parade recently, as the backup was over ½ a mile just to enter the parking lot.  (It takes a while to get 500 cars into a parking lot at the same time.)  While my electric car may be no faster than a cheap economy car on the highway, it more than makes up for it with its slow driving manners.

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