11/09/2017 Event
HOW AUTOMATIC TRANSMISSIONS HELP YOU SAVE MONEY
A computer that chooses the right gear for you and transmissions that consume less are just two of the reasons you should say goodbye to your clutch forever.
Don’t kid yourself. You might think you're a math genius, but there are devices that are smarter than you when it comes to choosing the right gear. If you spend half your time with one hand on the gearshift and want to cut your fuel bill, this post about automatic transmissions is for you.
Today, vehicle markets everywhere are wholeheartedly embracing transmissions whose computer selects the right gear. So is there some global conspiracy to do away with manual transmissions? Not really — the fast-paced trend has more to do with carmakers’ efforts to win the war on fuel consumption.
The truth is that manual shifting is not always carried out at the ideal time. We, the drivers, decide when. And, let’s face it, we don’t always get it right. That’s why the advances being introduced take the driver out of the equation to help improve fuel efficiency.
Dispelling Common Myths
In the past, automatic transmissions were seen as guzzlers. That’s no longer the case. You can actually save moneywith one — if you use and maintain it correctly. As you may have already guessed, you need to follow the manufacturer’s instructions about changing the transmission fluid.
Automatic transmissions select the gear ratio according to the data they receive regarding vehicle movement. A computer selects the most appropriate gear at all times, improving engine and transmission performance to deliver maximum efficiency. This helps manufacturers achieve their fuel economy goals.
Plus, continuous technological advancements have reduced energy use by automatic transmissions 10% compared to manual transmissions. And all these reasons are why 50% of vehicles manufactured today are equipped with automatic or semi-automatic transmissions. The market is expanding rapidly in countries such as the United States, Japan and South Korea.
Types of Automatic Transmission
There are several types of automatic or semi-automatic transmission.
Semi-Automatic Transmissions: These are the ordinary manual transmissions that include an automated manual transmission (AMT). Also known as clutchless manual transmissions, they are very popular in Europe and can be found in Alfa Romeo (Selespeed), Audi R8 (R-Tronic), BMW (SMG), Citroën/Peugeot (CMP), Fiat (Duallogic), Lancia (DFN) and Opel (Easytronic) vehicles, among others. They use the same transmission fluid as manual transmissions, although other products are required for automatic transmissions.
Automatic Transmissions: These are the traditional automatic transmissions with torque converters and planetary gearsets. A computer uses a hydraulic system to automatically change the gear. These transmissions require specific lubricants, such as Dexron or Mercon; the type used varies with the carmaker. The fluids must be replaced roughly every 60,000 kilometers. The transmissions can have four, six or eight gears, sometimes even more, and are very popular in the United States, Japan and South Korea.
Continuously Variable Transmissions (CVT): We covered this type of transmission in an earlier post. Two cones are connected by a belt that continuously drives a hydraulic variator to change the rotation speed and diameter of the cones. This system is used in Audi (Multitronic S), Jeep and Dodge (Autoshift), Mitsubishi (6S-CVT), Subaru (E5-AT Sportshift) and Mercedes (Autotronic) vehicles, among others. Japan and China are the largest markets. Specific fluids should be used depending on the type of transmission.
Dual-Clutch Transmission (DCT): This can be described as two separate manual transmissions, one for the even-numbered gears and the other that for the odd-numbered ones. Two clutches decide which axle is to be used, while the computer controls the clutches and the gears. This type of transmissions is gaining in popularity in Europe and China. The marques using this system include Volkswagen (DSG), BMW (DKG), Ford (PowerShift), Nissan (ATTESA E-TS), Volvo (Powershift) and Porsche (PDK). As already explained in a previous post, some DCT transmissions use dry clutches and others wet ones, i.e. bathed in oil. Dry single-plate clutches are more common and need a specific transmission fluid. Manual transmission fluid is unsuitable.
If you decide to go for one of these money-saving transmissions, remember what we always say here at Total: always use a premium lubricant that meets the manufacturer’s engine oil or transmission fluid specifications. Each type requires its own specific fluid.