You may have noticed that AMSOIL Fuel Efficient Synthetic (ATL) and Multi-Vehicle Synthetic ATF (ATF) are now recommended for electronically controlled continuously variable transmissions (eCVTs) in certain vehicles.
eCVTs, such as those found on the Toyota Prius, are significantly different from belt- and chain-driven continuously variable transmissions (CVTs). Several automakers use CVT technology, so it’s important to understand the differences between belt-and chain-driven CVTs and eCVTs, which are closer to traditional step-type automatic transmissions in design.The primary purpose of any transmission, regardless of type, is to transfer power from the engine through the drivetrain and, finally, to the wheels. To do so, it must work within a narrow engine rpm band to ensure it produces enough torque for the immediate needs of the vehicle and then transmit that torque to the driveline. Getting a heavy vehicle moving from a dead stop requires a lot of torque.
Step-type automatic transmissions use a set of gears called planetary gears that work together in different combinations called gear ratios. These gear ratios make it possible to get a vehicle moving from a dead stop and continue a smooth pattern of acceleration all the way up to cruising speed. Each “step” is simply the transmission changing from one gear ratio – or one speed – to the next. Traditional automatic transmissions select a low gear ratio to get the vehicle moving from a dead stop. As the vehicle builds momentum, less torque is required to keep it moving and the transmission shifts to higher gear ratios in sequence, slowing the engine at each step until the vehicle is at cruise.
Traditional automatic transmissions have been in use in the U.S. for over half a century. The efficiency of this technology has been enhanced over the years, but there is always room for improvement. With ever-rising fuel economy standards, auto manufacturers spend a lot of time looking at ways to use the transmission to improve the engine’s efficiency. Each engine design produces its most efficient power at a predetermined rpm – the “sweet spot.”
One key to better fuel efficiency is keeping the engine in its sweet spot for as long as possible.When you drive a conventional step type automatic transmission, you feel the rpm rise and drop each time the transmission shifts to the next gear ratio. Each one of these bumps is an inefficiency that consumes extra fuel because the engine is taken out of its sweet spot. The same is true when you’re climbing a grade and the transmission drops into a lower gear, making the engine run faster and use more fuel.
One way manufacturers address this issue is by adding more gear ratios. This has the benefit of shortening the duration of the bumps and gives the transmission more options to keep the engine at its optimum rpm. The inefficiencies can’t be completely eliminated, however, because the transmission is physically limited by a finite number of gear ratios. CVTs take a different approach to managing rpm. Instead of gears, the most common CVTs in the U.S. use a metal belt or chain running between two pulleys. These pulleys are designed to spread open or squeeze closed under hydraulic pressure, forcing the belt or chain to ride higher or lower in them. The advantage of this system is the vehicle’s computer can quickly and continuously adjust the pulleys to whatever ratio is required for peak efficiency because it isn’t physically limited by gears. When driving a CVT equipped vehicle the driver pushes on the gas pedal and the CVT adjusts to keep the engine at its most efficient rpm through the entire acceleration process.
There are no bumps or rpm increases felt by the driver. This is even true when climbing a grade. The engine stays at its most efficient rpm and the CVT adjusts to allow the car to get over the hill. The eCVT found on the Toyota Prius and other hybrids differs from CVTs found in other vehicles, such as the 2013 Nissan Altima or 2012 Scion iQ, because it does not use a belt or chain connected to a pair of variable pulleys. Instead, an eCVT uses electric motor/generators to control the speeds of planetary gearset components. This allows the eCVT to continuously change the gear ratio, keeping the engine’s rpm in the sweet spot. Just like when driving other CVT-equipped vehicles, drivers of vehicles with eCVTs don’t feel the step change common to traditional automatic transmissions, yet the mechanisms (planetary gears) to achieve acceleration are largely the same.
Recent test data has shown we can confidently recommend AMSOIL Fuel Efficient Synthetic Automatic Transmission Fluid and AMSOIL Multi-Vehicle Synthetic Automatic Transmission Fluid for eCVTs, and they will deliver the same high performance in eCVTs as they do in traditional automatic transmissions.
Epic Boat-Hauling Story Clinches AMSOIL Toughest Tow Contest The AMSOIL Toughest Tow Contest solicited extreme towing stories about how AMSOIL Signature Series Synthetic Automatic Transmission Fluid’s reserve protection against heat and wear ensured top transmission performance. AMSOIL received many impressive stories over the course of the contest, but AMSOIL Dealer and hauler Robert Ransom Williams IV of Mexico Beach, Fla. earned the top prize of $1,000.When the owner of the largest yacht dealership in Houston, Texas called Williams in Norfolk, Va. on a Wednesday afternoon, he was up against a wall. Five 32’ Scarab center-console boats with twin 250 engines had to be in Houston by Monday afternoon, but three were at dealerships in New Jersey, while the others were on the east coast of Florida. After a quick call to fellow hauler Donald “Chigger” Andrews for assistance with the New Jersey boats, and consulting with his trusted navigator, basset hound Daisy Lee, Williams accepted the challenge.
“We had two empty triple-axle trailers ready to roll, so within the hour we had both the big Cummins fired up and were headed north toward the Jersey Shore,” said Williams. “My partner, Cindy ‘Big Guns’ Kimmons, had some towing experience, but this was to be her first transcontinental multi-day trip. She was at the helm of my Dodge Ram 2500, while I was in the lead in the Ram 3500 Dually. Both trucks sported legendary Cummins 5.9 turbo-diesel engines and were lubricated with AMSOIL products from stem to stern.”Reaching Cape May, N.J. by Wednesday night, Williams and Kimmons were making good time, and they spent Thursday driving up the Jersey Shore, loading the boats and going through countless toll booths.
“Friday dawned as we crested the Blue Ridge Mountains,” said Williams. “Both trucks were pulling like angry mules and the boats were riding easy on the big triple trailers. This is when the confidence of knowing you are running AMSOIL ATF really pays off. Yanking 15,000 lbs. over the mountains at 70 mph is a stern test for any automatic transmission, and this tough tow was no exception.
‘Chigger’ was about a half-day behind us, and I seriously wanted to beat him to Houston. Our friendly rivalry pitted my Dodge Rams against his heavy Chevy with a new Allison transmission. He was using AMSOIL ATF in the one-ton dually tow rig, but swore by Rotella to lube the Duramax engine. We would just have to see.”Williams and Kimmons reached Houston by noon Saturday to unload the first two boats. “We waved to ‘Chigger’ about half an hour west of Beaumont on I-10,” said Williams. “He was making good time, but I could not resist giving him a rev as we were back light-loaded and flying toward the Sunshine State.”
The trucks ran perfectly over the long drive to Daytona, and they were loaded and on their way back to Houston on Sunday. “I was thankful that the weigh stations were closed as the brand-new Scarab beauties we were towing were nearly 10’ wide. Florida, Alabama, Mississippi, Louisiana – the states were clicking by, our transmissions were running cool and when the sun came up Monday morning, we could see the Houston skyscrapers on the horizon. We were going to make it, and AMSOIL products were a big reason why. Hauls like this one are made possible because of the extended change intervals offered by AMSOIL synthetic lubricants. AMSOIL synthetic gear lube, motor oil and ATF all provide the ability to get the most out of your towing equipment, and we certainly did.“The Houston dealer was both thrilled and impressed when we pulled into his shop with three hours to spare on Monday. He stroked me a fat check with a big smile on his face and told me that all five boats were being fitted on cradles and were to be loaded on an airplane that afternoon. Destination? Sierra Leone, Africa. Thanks to AMSOIL for making this tough tow possible, uneventful and highly profitable.”
