Transmission technologies



If you’ve been looking at buying or leasing a new car, we’re sure you’ve discovered that a lot of things have changed “under the hood”.

At Natural Resources Canada, we think that a little knowledge can go a long way toward helping you find a vehicle that will deliver good gas mileage and reduce greenhouse gases, effectively harnessing these new technologies for your – and the planet’s – benefit.

Let’s talk about changes in powertrains, and how they’re helping make vehicles more efficient.

Gears – The more the merrier.

We’re sure you’ve seen how sophisticated bicycles have gotten, with 21, 24, 27 gears and more. Why are bicycles set up this way and why are they so popular? Because there’s a gear for every situation, from the flattest straight to the toughest incline… and everything in between.

Let’s take that principle… lots of gears… and apply it to your vehicle.

Additional gearing in traditional transmissions – manufacturers are now offering 7, 8 and even 9-speed transmissions to give the car more ratios to create more opportunities for the car’s engine to work within its “sweet spot” (a certain power band measured in RPM in which torque, horsepower, revs, and efficiency are optimized).

By the way, these choices are made seamlessly in automatic transmissions by on-board computers; and if you like to shift for yourself… you’ve got a choice for every condition. These types of transmissions can give you between 6 and 8% better fuel efficiency compared to traditional transmissions.

CVT (continuously variable transmissions): Keeping it Simple!

CVTs are infinitely variable transmissions and they’re becoming more and more popular. The beauty of the CVT is its simplicity: it does away with the traditional limitation of “gears” in order to find the best possible ratio for the physical conditions of the vehicle.

Modern CVTs work a lot like the simple snowmobile transmission, in which two clutches “interact” with one belt to change ratios constantly. The transmission itself and associated computers sense changes in terrain and throttle pressure, and adjust the ratio accordingly. What is special about a CVT is that choices for that ratio are essentially infinite, because there are no gears.

The result is no traditional shifts – and up to 7% better fuel efficiency.

Two clutches, no waiting!

Dual clutch automatic transmissions are significantly more efficient than traditional automatics.

This transmission differs from a traditional automatic transmission in that it has two clutch packs instead of a torque converter to help reduce fuel consumption; one clutch for even-numbered gears, and the other for odd-numbered gears.

This allows the vehicle to preselect the next expected gear ratio sooner.

Resulting in smoother shifting.

Dual-clutch transmissions deliver from 6 to 9% better fuel efficiency compared to a traditional 4 speed automatic!

Stop-start technology: an open and shut case!

It’s been proven that unnecessary idling wastes fuel and creates greenhouse gases and other types of pollution. What if we just… turned the car off? That’s how idle stop-start works.

When your vehicle comes to a full stop – at a set of traffic lights, for instance – your engine shuts off for that brief interval, and restarts when you release the brake, and press the accelerator in order to get going.

An on-board computer senses when you’ve come to a stop… and senses when you take your foot off the brake to get the engine going again.

Now don’t worry – your lights, heating or air conditioning, audio controls and other systems keep right on working during this brief interval.

By the way, idle stop-start vehicles typically have more robust starter motors and batteries in order to manage this increased starting activity.

The system has been proven to have no detrimental effects on your starter motor or other driveline and engine components. And did you know that there is also new technology that uses the energy from braking to store power for those start-ups and lessen the effect on your battery using regenerative braking and a sophisticated capacitor to store electricity.

Idle stop-start: a classic example of technology working simply to provide big returns.

Okay – that’s it for now.

Here’s the thing to remember: all these technologies have been created as manufacturers try to squeeze more and more efficiency out of powertrains.

At the end of the day, you benefit, and so does the environment. So reflect on how you drive, where you drive, and how much you drive as you choose your next vehicle… and enjoy the advantages of these new technologies!