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!
As far I can tell, this is a problem worth solving for electric engines on city streets. I can see some internet material about how trolleybuses in Brisbane are said to have earned the charming nickname 'whispering death', due to their sexy silent-running engines resulting in a tendency to sneak up on inattentive pedestrians. Most manufacturers have learned the lesson to include a noise-making component in their engines rather than putting the burden on drivers and pedestrians to be infallible. Mandates may end up causing the noise-maker to sound more obnoxious than it strictly needs to be.
Another note: how much transport technology seems to be decided by people's fetishes rather than evidence. Gas tanks and batteries are both vats of chemicals. This blog post lays out localized but convincing objective evidence that batteries are great to have but don't cover 100% of a car's use cases, making a hybrid car a much more logical compromise than a pure electric car. But everyone talks about Teslas and the supposed inevitable transition to 100% battery cars, although the economics of getting that many vats of those particular chemicals don't seem to add up.
I am emotionally partial to trains, streetcars, and trolleybuses that run on electric wires, preferably while making a tasteful sizzling noise. This is likely a huge bias, but it does make me notice how much emotional trends currently run in the other direction, infesting public decision-making with hatred of wires (or anything else that they will have to exhibit further diligence in maintaining). TTC will now, instead of expanding its bus fleet to run more service (with the logical option of diesel or hybrid buses) in areas with latent demand for service, use the resources to purchase sketchy and experimental buses from three battery-bus companies. Likewise Metrolinx has been tasked with 'electrifying' GO Transit, and has exhibited a decided aversion to trains that run on electric wires. Instead, they want to study hydrogen, a technology that does not actually exist for trains outside of tiny experiments by German and Japanese rail companies. (The Metrolinx stance on overhead wire being 'outdated' reminds me of the Soviet joke about a movie studio that wasn't making any movies because silent film was already obsolete, but non-silent film was not developed yet.) The Quebecois likewise want a reasonably cheap passenger link between Montreal and Quebec City. Because electric trains are unthinkable and have clearly never worked anywhere else in the world, their government got some guys to make 3D renders of a silly suspended monorail thingy that appears to fit 1/20th the number of passengers. Periodically the Hyperloop sellers pop up, but since the spec has been revised from "dirt-cheap scary claustrophobic projectile inside a paper-thin tube" (Musk's original whitepaper) to a more physically feasible but monstrously expensive and complex maglev pod inside a similarly monstrous and complex vacuum tube, I would bet safe money on no one ever building a Hyperloop at intercity scale.
I can't claim to know what mixture of cars/buses/trains makes sense for North America economically, but I can and will make fun of the local culture of ignoring careful incremental engineering experience from elsewhere in the world as 'obsolete', and then proceeding to not build things based on technologies that don't exist.
Agree re. ensuring some noise. It's interesting that Toyota decided to invent this weird choir/chime thing that isn't obvious to anyone, instead of something like the "beep beep beep" of reversing trucks. Hope there was some science there, but who knows.
And doubly agree re. the fashionable decision-making of urban transit mavens. They can afford to do so, because someone else is paying the bills, they get to bathe in the virtue press, and are not held responsible for the inevitable failures. But enough about government. :-)