As automakers strive to improve internal combustion engine efficiency, more functions are switching to electrical from mechanical. That's the case with camshaft phasers, the devices at the ends of camshafts that vary the timing of the intake and exhaust valves to improve performance, reduce emissions and keep the engine running in its "sweet spot."
Until now, cam phasers have been activated by oil pressure. But when the engine is cold and the oil is thick, cam phasers are slow to react and cause the engine to work harder to pump the oil.
Schaeffler engineers have addressed that problem with electric cam phasers, which respond faster and reduce oil pumping losses. Nissan's Infiniti luxury division uses electric cam phasers on V-6 engines such as the 3.5-liter in the QX60 midsize crossover.
Electric cam phasers offer another major benefit. After the engine is turned off, the phasers can position the valves for faster, smoother and more efficient starts. This is especially beneficial for hybrids and vehicles with stop-start systems.
"We don't want to wait for oil pressure to be good enough to operate the cam phasers," said Andrew Mlinaric, a senior product development engineer at Schaeffler. "We want to be in the optimum position right at startup.
"The main benefit is comfort," he said. "And on a hybrid application, you want the engine to start up as fast as possible."
