The Woods Motor Vehicle Company was dead and gone by the end of WWI, but they were oddly prescient with many of their ideas. For example, they had a gasoline/electric hybrid vehicle way back in 1914, the Dual Power Model 44. This wasn't the first hybrid ever, but it does show that they were seriously experimenting with the technology.

Now, at the time gasoline was still too cheap and people had yet to develop the ability to be really self-satisfied based on their fuel choices, so the car never took off, and the company didn't survive. But, during Woods' brief, innovative life, they did come up with one especially interesting prototype: the Woods Interurban.

The Interurban was an electric car, but only sometimes. Sometimes it was a gasoline car. It achieved this act of automotive schizophrenia not by being any sort of dual-motored hybrid monster, but rather by letting the driver choose to transplant one engine type for the other based on the trip: if it was local, stick with the electric. Going on a long trip? Pop in the gas motor.

See? The first car with intentionally swappable engines. It was a failure, and like almost all good failures (gum-filled Combos, rocket boots), I think it's worth another go.

In the case of the Interurban prototype, the electric motor could be swapped for an 8 HP two-cylinder gasoline engine, and the process was said to take about 15 minutes, which, for the era, was impressive. There's only one picture that seems to be the Woods Interurban, and looking at it shows a car with what appears to be a large, removable hood, and a design and layout very similar to Renaults of the era. Like the French cars, the Interurban looks to have its radiator mounted behind the engine, which may have made engine removal/replacement easier.


There's not much information available, but I suspect the reason the car was never developed further was because of the logistical difficulties in keeping around an extra motor to swap, and the mechanics of the swap itself.

Back in 1914, these problems must have seemed pretty insurmountable. But, nearly 100 years later, this is a very different story. Technology's changed a lot. Back then, if you wanted to play Angry Birds you had to hike on down to an aviary with your own rocks and pigs and slingshot. Today, the same activities can be had with something in your pocket. With the automotive industry, the changes are equally dramatic.

1914 and 2013 share one key thing when it comes to electric cars: nobody's really happy with batteries. Yes, battery technology has improved dramatically, but despite a century of work, we're still stuck with heavy, relatively inefficent batteries that make 100 mile+ ranged electric cars a rarity. The Nissan Leaf, currently the most popular pure-electric car, can go between 47-105 miles per charge, according to Nissan. In town, that's fine. But it just doesn't cut it for long trips.


Sure, some companies are pushing range-extending gas-powered trailers as an option, but those are clunky and heavy solutions, and driving a car with any kind of trailer is a pain in the ass, especially when it comes to backing up. There's got to be a better way.

And there is: revisiting the 1914 Woods Interurban engine-swap solution. By having separate, swappable drivetrains for our hypothetical New Interurban, a more limited set of batteries with a 40-50 mile range would be fine for city use, and a variety of gas motors could take the place of the electric motor/battery pack when needed.


The way I think this could best be done today is by having the whole drivetrain, with wheels and axles, swappable. As applied to a front-driver car (the most likely configuration) the entire front assembly would be swappable, including the front subframe with wheels, transaxle, gasoline engine with tank or electric motor with battery pack. The front fascia of the car may be a part of the unit as well, as the gas motor will require a more substantial radiator and cooling system.

Modern drive-by-wire controls would make interfacing brake, throttle, steering, and other functions vastly easier, with only electrical connections needed to and from the engine unit and the rest of the car.


To make this a viable proposition, the engine swap has to be as easy and painless as possible. Ideally, it will resemble nothing like a conventional engine swap, even a really, really fast one. No lifting, no grease and oil, no exertion of any kind. Ideally, the drivetrains should be able to be swapped in five minutes or so.

How? Well, it'll take some special infrastructure. Thats okay, since I'm just imagining this, and in my imagination I was approved for an imaginary loan with a surprisingly brutal interest rate that lets me spend whatever I need to make this happen. I like to keep my imagination a bit grounded. Also, in this scenario I'm imagining I have a jetpack, but my license for it was suspended.


The way to swap these drivetrains is to, essentially, roll them in and out,. To do that we'll need special swapping bays that are like regular parking spaces, but with a central guide rail. This rail both supports the front of the car when the power pack is rolled out, and the non-wheeled part of the power pack itself. You'd pull into a bay, tell your car you were ready for a swap via some manner of dash control, which would cause the car to unplug is electrical connections to the power pack.

Then, and these steps would be either automated or with actual, huggable humans, the front bumper assembly would be released and moved, the few physical mounts and connections would be released (ideally via tool-less means) and the whole power pack/front wheel assembly would be rolled away. In is place the other power pack (gas or electric) would be rolled into position, connected electrically and physically, and off you go.


The electric pack would include a central spine of batteries; in the gas version this volume would contain the gas tank, which would likely need to mate with a filler tube/cap assembly on the car. Once out of the car, the power pack would be recharged (in the case of an electric one) or serviced, and then stored to await the next car that needed it.

You could just swap depleted electrical power packs for charged electrical units, if wanted as well. Or, a variety of performance levels and sizes of gasoline engines could be offered as well.

I like this solution because it takes a bold, harsh look at the problem of battery range and bravely turns and runs away, into the welcoming arms of good old gasoline. Or diesel, for that matter. Or biofuel or CNG or whatever. Having a power-and-fuel agnostic car design means the job dictates the best choice to power your car, instead of having to try and cram one solution for everything.


So what do you think? How viable is this century-old idea I'm stealing?

CLARIFICATION UPDATE: Some people have been saying, wisely, that people wouldn't want to have to store an extra drivetrain. I agree. I was picturing this as something where a dealer or service facility keeps the engine you're not using. You don't really "own" it, when you buy your car you have a contract that you get whatever drivetrain you want from any authorized service center. So, you drive in, drop off your electric drivetrain, pick up your gas motor, take your trip, come back, and on your way to work the next day have another electric drivetrain popped in.

This also means no service is ever needed on your engine, since you're getting serviced units every time you swap. In theory, you could never swap, but part of the purchase may stipulate some mandatory maintenance swaps, for some period of time. Make sense?