A new compact exhaust system now in prototype development is aimed at hybrid-electric and plug-in HEV applications. It is designed to "fit within a small packaging footprint on electrified vehicles," Mike Clegg, Chief Technical Officer and North American Vice President of Innovation & Advanced Engineering at Faurecia Emissions Control Technologies, told AEI.
Faurecia's exhaust system features a fabricated manifold with integrated close-coupled catalytic converter, referred to as a "maniverter." Additionally, the prototype's ultra-thin-wall (0.8-mm/.0315-in) pipes control the flow of exhaust gases to a safe exit point on the vehicle. The pipes also facilitate sound control as does the system's main muffler and its small resonator unit.
"For acoustic control and to further reduce the weight of the exhaust system, electric and adaptive valves are available as options. And, the system can incorporate a heat recovery system," explained Clegg.
Compared to a conventional exhaust system, the Faurecia concept prototype is considerably smaller.
Although the size and weight of Faurecia's exhaust system is based on several variables—including location within the vehicle structure and engine configuration (i.e., inline or V-type)—the most likely configuration is 3 to 4 ft (0.9 to 1.2 m) in length, 2 to 2.5 ft (0.61 to 0.76 m) in width, and 1.5 to 2 ft (0.46 to 0.61 m) in height.
The exhaust system's weight would vary between 30 and 40 lb (13.6 to 18.1 kg), depending on the use of the company's patented Exhaust Heat Recovery System (EHRS) and/or the patented Adaptive Valve technology.
"The EHRS, if integrated into the exhaust assembly, would collect and direct heat to the vehicle heating system via the use of the engine coolant, which is heated by the EHRS when needed," Clegg explained.
Faurecia's concept prototype exhaust system uses reactive and dissipative tuning to control the engine's sound output.
"Reactive tuning is based on reflective wave control of sounds. Dissipative tuning is the use of absorption material to transform sound into heat," he said. "The system also uses heat management components, such as insulating shells or a heat shield, to prevent overheating of parts that are close to the exhaust system."
The exhaust system is designed to be flexibly packaged, depending on engine and powertrain configurations. For compatibility with diesel engines, an aftertreatment suite including diesel particulate filter (DPF), selective catalytic reduction (SCR), or other emissions control components would be added. The DPF or SCR likely would be used in place of the resonator or muffler since those components provide a level of acoustic control, according to Clegg.
Once a specific engine/vehicle application is lined up, Faurecia engineers could have a production-ready exhaust system within two years, Clegg noted.