18 Jan Variable Valve Timing Improves Engine Efficiency
Quality oil is vital for keeping sensitive components clean
Variable valve timing (VVT) is one of the big-three engine technologies (along with turbocharging and direct fuel injection) automakers have turned to in the last several years to meet increasingly strict fuel-economy and emissions requirements without sacrificing vehicle performance.
Although it sounds complicated, VVT is based on the simple principle that engine efficiency can be increased by adjusting when the engine’s valves open and close. Say you’re cruising down the highway and approach a logging truck. As you depress the accelerator to pass, an engine with VVT can quickly adjust when the valves open, allowing the combustion chamber to fill with air and fuel more efficiently. This results in better torque, helping you easily pass the truck and be on your way. When you let off the accelerator, the VVT system adjusts the timing again relative to your driving conditions so the valves open and close in a way that returns optimum efficiency at lower engine speeds. Overall, the vehicle delivers increased torque and fuel economy while cutting emissions.
The keys to the system working are the components responsible for advancing or retarding valve timing in response to driving conditions. Although each system is slightly different, they all use motor oil as a hydraulic fluid to move the necessary components. Many accomplish this with cam phasers that provide extra rotation to the camshaft, thereby adjusting when the valves open and close. VVT components typically contain tiny openings through which the oil must flow in order to function properly, as you can see in the images. The solenoid pictured, from a 3.5L Ford* EcoBoost* engine, contains openings .007 of an inch across, which is about the thickness of two sheets of paper.
The solenoid directs oil flow based on a signal from the computer. Pressurized oil enters the middle ring (where most of the deposits are on the solenoid). Then it sends oil out the top or bottom ring to advance or retard timing. In the case of this engine, deposits prevented oil from flowing properly. The computer detected incorrect valve timing, illuminating the check-engine light.
Even the slightest amount of deposits can lodge in these tiny openings and negatively affect the system. In some cases, dealerships view these problems as non serviceable and recommend engine replacement instead of repairs.
The good news is, many VVT issues can be avoided simply with a combination of proper maintenance and high-quality oil and filtration. AMSOIL synthetic motor oil resists deposits and sludge better than conventional oils, helping keep sensitive VVT components clean and functioning properly. It also resists viscosity loss, meaning it consistently performs the duties of a hydraulic fluid, which is vital to proper operation of VVT components.
The vast majority have VVT engines, so stress the importance of following the appropriate oil change guidelines. Many engines with VVT are also turbocharged, including the EcoBoost from which this solenoid originated. Turbocharged engines automatically fall under our severe-service category, meaning customers who use Signature Series
Synthetic Motor Oil can extend their drain intervals up to 15,000 miles, 700 hours or one year if they choose. Even if a customer is not interested in extended drain intervals, Signature Series is an excellent choice for maximum engine and turbocharger protection.
They should also be using AMSOIL Ea® Oil Filters. They offer a filtering efficiency of 98.7 percent at 20 microns. Twenty microns is roughly 10 times smaller than the openings in the solenoids pictured. Compared to conventional filters, Ea Oil Filters do a better job trapping and holding the deposits that could otherwise end up negatively affecting VVT components.
VVT systems aren’t going anywhere anytime soon. The challenges they present to motor oil are really opportunities in disguise. Selling a high-quality synthetic motor oil and advanced filters becomes easier when your customers realize the importance of superior protection to the life and performance of their vehicles.