YPE html PUBLIC “-//W3C//DTD XHTML 1.0 Transitional//EN” “http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd”> As most gearheads are aware, the valve train acts as the lungs of an engine, managing the intake of air for combustion and the discharge of post-combustion exhaust. Modern engines control these inputs and outputs through complex mechanical means, but traditional mechanical control has its drawbacks. First, valve trains are complex and therefor expensive to design and manufacture. Second, once a valve train is built, its mechanical control methods can’t be modified to meet new operating conditions. In their latest foray into engine technology, engineers have built a hydraulically actuated system that is controlled electronically by a solenoid coil. “As soon as a control current flows, a specially designed hydraulic valve opens, allowing hydraulic fluid to open the gas exchange valve to the desired extent in milliseconds counter to a spring. When the current is switched off, the gas exchange valve is closed again by the spring force and feeds a large part of the hydraulic energy required for opening back into the hydraulic system. The syste...