Precision Flow EGR Cuts NOx, Sips Fuel

Volvo developed Precision Flow exhaust-gas recirculation (EGR) to improve fuel economy by 3 percent even as they met EPA's 2007 emissions standards for on-road diesel engines. An electronic turbocharger actuator on the D11, D13 and D16 engines accurately controls backpressure, and a near-side EGR valve close to the turbo precisely regulates flow as the driver modulates his foot on the accelerator. Volvo confirms flow with a downstream pressure sensor. The net result? "We get exactly the amount of cooled EGR we need — no more, no less — which improved fuel economy while meeting emissions," according to Volvo.