Many new vehicles on the market today are equipped with engines that offer variable valve timing , but what does this mean exactly? Well, this technology basically improves performance by allowing the engine to adjust to different driving conditions, whether the car is racing along a highway or just puttering around town.
The setup of variable valve timing systems varies between different makes and models. Different automakers have their own acronyms for specific systems, such as Honda's VTEC (variable valve timing and life electronic control), Toyota's VVT-i (variable valve timing and lift with intelligence) and Nissan's VVL (variable valve lift).
These systems all essentially operate the same way, with minor differences. The Honda VTEC system is one of the most common setups, and it involves three steps to regulate engine function. The first is low-RPM driveability, where the engine uses a camshaft designed to offer a smooth ride, good fuel economy, low-end power and torque.
The VTEC system also includes a high-RPM performance setting, which is designed to take over when the engine computer signals that this mode would be better for the driving conditions. The engine will switch to a high-performance camshaft that allows the vehicle to access more power at higher RPMs. An on-board computer monitors the driving conditions, throttle position and engine speed to determine when to switch from low to high RPM settings.
This system was originally intended for sports cars and other high-performance vehicles, but it is growing more common among other cars and light trucks as a way to improve fuel economy. It also provides better torque and can even help to lower emissions. This is possible because variable valve timing allows for better handling of gases when they are still in the engine, ensuring that more of the noxious substances pass through the exhaust system and are filtered before they exit the vehicle.
Expect to see variable valve timing become even more commonplace in new vehicles, as automakers are racing to meet corporate average fuel economy (CAFE) standards set in place by the federal government.