What do you know about hybrid cars? Lots? Then you probably won't learn much here, sorry!

Until two weeks ago, I knew very little.

Until four weeks ago, I had little reason to learn about it. There was too much hype, maybe a bit of smug, and the family had all the cars it needed. But then our little sedan decided it could do without one of its wheels. Unfortunately, it made this decision while in traffic. Fortunately, this happened close to home. After 22 years with little brown car, it was time to let her go.

But we still need two cars. Some requirements from me and the missus: four wheel drive, not gross on gas, not grossly expensive, large enough for our soon-excruciatingly-tall boys and our scouting gear. Quickly, a Big Manly Pickup Truck was imagined then ruled out. I hate having too much choice, so I decided to narrow things down to hybrids. Two weeks later, hello there, "Cargoyle", our new Toyota RAV4 Hybrid. Assembled just a few miles away, just a few days ago.

OK, so what? I had no idea how neat it would turn out to be.

A brief recap on car technology. Normal gas/diesel cars burn fuel to turn an engine, which in turn powers the wheels and electric accessories. Old school, works fine, always burns gas. Recent models have tricks to shut parts of the engine off when not needed, whether individual cylinders, or (when stopped at a light) the whole thing.

Electric cars like the Tesla series and a few others have big-ass on-board batteries to power the vehicle. They have regenerative braking (so slowing down charges the battery). When the battery's empty, you're stuck for a slow or not-quite-as-slow recharge. Plus big batteries = big cost.

Hybrids cars, like the original Toyota Prius / Honda Insight from fifteen years ago, are a normal car, with a little wee electric car hidden inside. A transmission lets both a little gas engine and a little electric battery/motor drive wheels. On-board software determines what to use when. There's a couple-thousand-buck cost premium over regular cars, much less now than originally.

Plug-in hybrids are a hybrid between hybrids and electric cars. They have an intermediate size battery that's worth charging at home, but a normal engine too. The downside: the battery is large/heavy and the engine small, so performance is often a problem. So is the cost of the larger battery.

Or in tabular form:

type propulsion battery size cost fuel consumption pros cons
Regular gasoline engine none low moderate low price, common fuel usage
Electric electric motor large high none futuristic high price, recharge delay
Hybrid gas+electric small moderate low good compromise moderate price
Plug-in Hybrid gas+electric largish high very low fuel sipper, no recharge delay high price, weak

The engineer in me appreciates the compromises and complications required in a good product. Balancing out many conflicting factors is IMHO an art. I get the sense that these wacky Toyota guys/gals did it well, really well. The thing that strikes me is how they managed to make a vehicle that's performant when needed AND a miser on fuel the rest of the time.

The performant part means that the vehicle should have enough acceleration to easily perform maneuvers like merging onto highway traffic. (Quite a few hybrids are anemic.) So, this guy has a medium but not small gas engine connected in parallel with two electric motors (front & back axles). When I floor the throttle, the thing takes off noticeably faster than any other common car I've driven. (OK, except that Ford Mustang I rented accidentally that one time in Boston.)

The miser on fuel part means the rest of the time, the engine is turned on as little as possible. It's ridiculous how little this can be:

  • When the car is stopped, the engine doesn't need to run.
  • When the car is slowing down, the engine doesn't need to run, and the battery charges.
  • When the car is urban cruising, the engine doesn't need to run, and the battery discharges slowly.
  • When the car is accelerating gently, the engine doesn't need to run, and the battery discharges quicker.

There is a pattern here! On the other hand:

  • When the battery gets low, the engine needs to run.
  • When the cabin is cold and the wimpy human wants more heat, the engine needs to run, just long enough to build heat in its coolant.
  • When the requested power level is high (accelerating rapidly, going uphill, going fast against air resistance), the engine needs to run to help the electric motors.

... but those can be rare. What does all this add up to? A gasoline system where the engine is tuned to run intermittently, and an electric system that tries to harvest energy whenever it can.

The thing is silent at rest. It is silent when rolling out of the garage or from a stop. Well, it would be silent, if certain influential people didn't fear silent vehicles, so they mandated that they make a noise. Our RAV4 gives a weird electronic chime / choir chord sound when going forward, and a louder version of the same when going backward. So it is "silent" when going down hills. It is "silent" when slowing down for a red light. It is "silent" scurrying around a parking lot.

Power consumption is smoothed out by the battery, so the power production by the engine can be intermittent and as brief as possible. The thing might turn on for 30 seconds here and there, climbing across a bridge or hill, or taking a longer/harder acceleration. Then it goes back to sleep -- while one's still just driving around. It's ridiculous. The power transmission is so smooth that I just can't feel in the throttle/brake response when the engine comes on and off. One would be barely aware, were it not for the little extra vibration, and the energy monitor display. Energy can flow to or from each of the wheels and the battery, changing instantly with the conditions.

Some of the engine-control thresholds are controllable by the driver. There is an "ECO" mode knob beside the "gear" selector. There are other modes where the engine cuts in more aggressively to give more acceleration by default, or charge the battery to a higher threshold, not sure. I haven't used these modes, because the novelty of the hybrid is maximized at ECO.

What's the fuel consumption bottom line? I still can't quite believe it, but when just goofing around in an urban chore, this comfortable medium-sized 4-wheel-drive SUV can sip less than 5L/100km, which is about 50 mpg for our American friends. At the same time, I can floor the gas pedal and get a comfortably strong acceleration -- noticeably more than Big Yellow Car with its larger 3.4L V6 engine, which by the way never consumes below 10L/100km. On a fully-loaded rainy-night crap-weather long highway drive, a worst-case condition for hybrids, we got around 7L/100km. As long as the machine keeps working, it will be our primary vehicle for fuel efficiency, comfort, safety (more air bags and sensors and stuff I could go into if someone asks).

Will report on disappointments as/when they arise, but so far so good!