31 May 2012
The ASME 2012 Internal Combustion Engine Division Spring Technical Conference was held May 6-9 at the NH Ambasciatori hotel in Turin, Italy. The conference was hosted by Politecnico di Torino. There were over 150 registered attendees and about 100 technical papers. The two- day technical program addressed a number of current trends in internal combustion engine development in seven parallel tracks: Large Bore Engines; Fuels; Advanced Combustion; Emissions Control Systems; Instrumentation, Controls, and Hybrids; Numerical Simulation; and Mechanical Design, Analysis, Vibration, and Lubrication. The conference concluded with a technical tour on the third day to the Politecnico di Torino Engine Research Center.
The conference started with a keynote address by Michael Potter, Chief Engineer, Diesel Advanced Engineering, GM Powertrain Europe. He discussed GM’s perspective on Development Trends for the Next Generation of Highly-Efficient Diesel Engines for Passenger Car Application. In order to demonstrate the potential of light-duty diesel engines, in 2010 GM started a demonstration project aimed at developing a highly efficient engine prototype based on an upgraded version of its popular 2.0 L diesel powertrain, which was then integrated into the Opel Insignia, with the objective of reducing CO2 emissions below 100 g/km at Euro 5 emission certification.
In order to reduce the motoring torque, base engine hardware was upgraded with low-friction and low-parasitic loss components including a high-efficiency low-friction vacuum pump, an electronically controlled variable displacement oil pump and camshafts supported by needle bearings. The combustion system performance and thermodynamic efficiency was enhanced as well by introducing a new-generation omega- shaped combustion bowl with low flow number 2000 bar piezo injectors.
The EGR system was equipped with a high efficiency, dual temperature cooler with the low temperature loop cooled by an independent, low temperature liquid circuit. The EGR system can be operating in three modes: at high load, both high and low temperature coolers are used. At medium and low load, only the high temperature cooler is used to avoid excessive CO and THC emissions. During warm- up, both coolers are bypassed entirely to provide uncooled EGR to the engine.
Thermo-management of the engine was controlled via a Valeo Themis 3-position valve instead of the conventional thermostat to allow engine coolant flow and temperature control based on engine power output and elapsed time after cranking. The coolant circuit incorporated three coolant pumps: a mechanical pump driven by the engine, an electric pump for start/stop operation and an electric pump for the low temperature EGR circuit. In addition to the powerplant changes, the vehicle incorporated start-stop and an optimally matched 6 speed transmission.
Compared to the current-production 2.0 L diesel Euro 5 engine, an improvement of ~10% of steady-state total engine efficiency was achieved in the NEDC relevant area of the engine operating map. This represents roughly 2/3 of the theoretical potential efficiency improvement in that area. An interesting observation was that over the NEDC, a major share of the input chemical energy was necessary to warm up the engine components and aftertreatment system to their operating temperature. In total, about 57% of the fuel energy was directed towards component warm-up and heat rejection. The low exhaust temperatures would also present a major challenge for NOx aftertreatment, with an underfloor SCR catalyst being particularly critical.
Next Conference. Next ASME conference—the 2012 ICE Fall Technical Conference—will be held in Vancouver, BC, Canada on September 23-26, 2012. the event will be hosted by Westport Innovations.
Conference website: asmeconferences.org/ICES2012