Catching Money as it Flies Out the Tailpipe

I have been giving a lot of thought to the efficiency of my car over the past few years. Yes, I agree with the "green" movement when it comes to transportation. I think we drive too much and waste too much gas in vehicles that are bigger and faster then we need. However, this is much closer to home for me.

You see about 2 years ago, before my third child was born, we realized there was a need for a better family car. Our existing vehicles (a Jeep, a small truck, and a small Kia Sephia) couldn't hold 3 kids at once. Small kids have to be in the back seat and in a safe and properly installed car seat. We needed a new car.

After months of searching, we finally settled on a certified used Toyota Sienna. Despite originally completely resisting the minivan market, that's what we ended up with. I like my newish car. It's a great vehicle and Toyota made some excellent design decisions. We can fit all three kids across the middle seats even with the larger (and safer) Britax car seats. This leaves the entire back of the van with its fold down seats available for hauling stuff. Packing up for trips to Grandma's or even just taking bikes to the park is a cinch and has the excellent feature of being able to haul more people when needed.

We had to sacrifice some ideals though. The car market does not cater to parents at all. We had three basic requirements: reliability, safety (which included room for all three kids' car seats installed properly and winter driving), and efficiency (our Kia gets 30+ mpg easy). We soon realized that there are no efficient cars on the market that would fit the seats. We looked at SUV's, Subaru, large sedans, and eventually... minivans. The closest thing to our original requirements is the Toyota Highlander Hybrid with its nifty fold down rear seat to make a third row, but it is marketed as a luxury car, to get it without leather seats and the deluxe options required a special order. Also, no car seats allowed in the back and only two latch spots in the middle. None of the other car dealers had anything close and no, I don't want a Ford Behemoth SUV, thanks.

So the Sienna van met all the requirements beautifully, except efficiency. There is no hybrid version of the minivan in the United States (there is one in Japan), despite weighing about the same as a Highlander. The van gets a respectable 30+ mpg on the highway, but in town it is down around 12mpg.

That's another thing. We live in a smallish town of about 30K people. This means we have about everything we need in town and rarely even have to drive the 9 miles to the next city. We might drive a whole 30-40 miles a week during the busy school year. I used to commute to work 1.5 miles each way. We could easily get by on an electric car that only gets 50 miles per charge. The only time we drive more is when we take the 45 minute or 1.5 hour trip to nearby cities or the 6 hour trip to Grandma's house. Now we have an excellent vehicle that gets 12 mpg starting and stopping every 2 blocks and rarely gets above 25mph. Occasionally, we will go the whopping speed of 30-35mph. I am willing to bet that a lot more people in the US then just me have this kind of driving style. They might drive more per week, but a lot of it is start and stop at low speeds.

So there you go, that's why I have been giving this lots of thought. Why aren't there more efficient family cars and what can we do about it? Short term not much but wait for the market demand to create new products. I think the demand is there and government regulation coming down the pipeline might speed the process for better or worse.

In the meantime, I noticed something. Everyone knows you get worse gas mileage starting out from a stop and moving at slow speeds. The best mpg is usually on the highway when speed and forward momentum means you just have to sip gas to maintain forward velocity. I didn't realize just how bad this effect was until I took advantage of a feature on our new van. It shows you a real-time estimate of about what it thinks you are getting in gas mileage as you drive. That 12mpg average really fluctuates. Most of the time we get about 20 mpg cruising around at 25-30 mph. However, starting out at those stop signs every few blocks means you are starting out only getting 1-5 mpg and then efficiency goes up as you gain speed. That is what kills the averages. All cars except for newer hybrids and some small and light 5-speed commuter cars get horrible in-town gas mileage.

Here is what I want to see:

An upgrade system for existing combustion engine cars. An electric single low-geared drive system that charges off of the alternator and runs at slow speeds. Your combustion engine still runs all the time, even just to idle when you are stopped. That means the alternator is constantly charging the battery, but after the main car battery is charged, that is all lost potential energy. I want to harvest that with a second battery system that could then be used to propel the car at slow (and very inefficient) speeds. If I didn't waste so much gas starting out and driving at slow speeds, I could potentially boost my in-town mileage up to 18 or 20 mpg. since that is a bulk of my driving, it might lower my gas bill 30%.

1. Install a secondary battery pack using the new Li-ion cell technology that they use in some electric cars and electric motorcycles (think of a box containing 50-100 small AA size Li-ion batteries). It can be in the engine compartment (as lots of cars have room for a secondary battery) or even place them in the rims or undercarriage. The shape of a grid of small batteries is highly variable. You could make it long and skinny, round, or even mostly flat. This battery pack would charge off of the alternator when the main battery is charged up. Possibly a generator / alternator upgrade would be needed, but that depends on the vehicle.

2. Install a small electric motor capable of only one speed, slow (basically it would just replace first gear). This could power the car out of a stop and up to 10 or 12 mph. This would have to be placed in the drive line and be able to engage and disengage as needed.

3. have some kind of transmission computer bypass that allows the cars computer to engage and disengage this electric motor instead of using first gear. In an emergency you would want the speed and power of the full engine, so it would also need a safety protocol that, depending on how fast the car needed to accelerate (how fast you were pushing down the gas pedal), it would decide whether to use or not use the electric "starter" motor.

Ideally this would be a conversion kit able to be installed by most mechanics for a reasonable price point. How much? I don't really know, but I would be willing to pay over $1000 for this. A $2-3000 system installed on a newer 30-50K truck, van, SUV, or large car sounds reasonable as it would have saving over the lifetime of the vehicle several times the installation cost. Not to mention potential subsidies and tax breaks. The point is it doesn't have to be fancy or big, it's a one trick pony designed to alleviate the single biggest single gas waste in my vehicle.

Depending on how it is wired up, you might even be able to move a car around a parking lot or driveway without even turning over the engine. Also, my minivan has a roof rack that doesn't get any use. I would be fine with strapping a $500 ergonomically shaped solar panel up there if it means I can cut my gas bill down while I drive back and forth across town.  (editors note:  especially if it powered the AC like on the new Prius)

A larger system for large industrial trucks would also be nice to see. Can you imagine how much gas UPS/Fedex/USPS could save in a year with all the starting and stopping their drivers do?

Is it possible? I don't know I am not a mechanic, but I am pretty sure a group of smart engineers could work out the quirks and the manufacturers would have to be partially involved on the transmission programming part.

Wishful thinking? I am not sure. Something has to be done, and if we are going to insist on continuing to release old technology combustion (which is cheap and powerful, I know) instead of moving to new technologies in cars, I want my family vehicle to be as efficient as possible in the meantime. This might be a fancy transitional upgrade, but it would still be better then the status quo.

Got something like this in development? Send it my way, I'll test it out for you. :)


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