The Metal Powder Industries Federation (MPIF) has identified variable valve timing (VVT) as a Powder Metallurgy (PM) Industry Landmark technology for its innovative and significant use of PM parts. The recognition was announced at PowderMet2010, International Conference on Powder Metallurgy & Particulate Materials, June 27–30, Ft Lauderdale, Florida, USA.
Originally introduced in the late 1960s, VVT systems began using PM parts in North American internal combustion engines in 2000. The technology assists automakers to meet environmental and fuel-efficiency standards by advancing or retarding the timing of the intake or exhaust valves. VVT allows cam timing to change, which results in improved engine efficiency and power over a wider range of engine RPMs.
The PM industry supplies an estimated 40 million PM steel parts for VVT systems annually in North America alone, which is projected to grow to 70 million parts annually by 2015. Most current VVT systems contain three complex PM parts, a vane rotor, sprocket, and thrust plate, weighing about one pound each. PM’s net-shape, weight-saving, high-volume part-to-part consistency and superior surface finish advantages provide substantial value to OEMs in this application. Making PM parts for VVT systems offers substantial cost savings over machining from wrought steel as well as precision thickness tolerances in the range of 30 microns. This application is one of the most outstanding examples of the PM industry’s innovative strides in the automotive market.