Opel's new generation 2.0-liter turbo diesel boasts of high power output and torque as well as low fuel consumption and emissions – as delivered with a best-in-class refinement. This new diesel engine will be first fitted under the hoods of the Insignia and Zafira Tourer, both of which will be shown at the "Mondial de l'Automobile 2014" in Paris, France.
Replacing the current 2.0 CDTI engine that delivers 120 kW (163 hp), the new 2,0 turbo diesel mill offers up to 125 kW (170 hp) of max output and 400 Nm of peak torque. Already compliant with Euro 6 regulations, the new diesel engine could generate five percent more output and 14 percent more torque than its predecessor. It also consumes less fuel and emits less carbon dioxide. Thanks to Opel's focus on 'sound engineering' measures to minimize NVH (noise, vibration, harshness), the new diesel engine is remarkably quiet and smooth.
Michael Ableson, Vice President for Vehicle Engineering Europe, called the new engine as a perfect partner for Opel’s top models Insignia and Zafira Tourer, thanks to its high power density, frugal nature, refined character and sheer fun-to-drive attributes. He added that with Euro 6 compliance, the new 2.0 CDTI engine already meets future requirements while significantly enhancing the appeal of Opel’s diesel portfolio.
Opel will make the new 2.0 CDTI engine available starting next year. This new mill is the first in a new family of large diesel engines that were developed in-house by a global team of engineers in Turin and Russelsheim, with support from engineers in North America. Opel will build the new mill at its Kaiserslautern engine plant in Germany.
The new 2.0 CDTI engine delivers a specific output of 85 hp per liter, which is the same power density as carmaker’s new-generation 1.6 CDTI mill. This means that the new 2.0 CDTI engine delivers as much energy from as little diesel fuel as possible. This new engine is a small but fun-to-drive mill that delivers 125 kW (170 hp) of max output at just 3,750 rpm as well as 400 Nm of peak torque available between 1,750 rpm and 2,500 rpm.
The impressive performance of the new 2.0 CDTI engine is thanks to features like its newly designed combustion chamber, re-profiled intake ports and a new fuel injection system that offers 2,000 bar and 10 max injections per cylinder cycle. With these elements, the new engine could deliver high power, enhanced fuel atomization and quieter operation. To achieve this, the combustion chamber was subjected to over 80 computer design simulations, before the best five were picked for hardware development.
Meanwhile, the engine’s variable geometry turbocharger (VGT) comes with an electrical actuator for the variable aspect turbine, allowing for 20-percent quicker boost response than a vacuum actuator. This fast response was also made possible by the compact packaging of the VGT and intercooler as this configuration minimizes the air volume between the turbocharger and engine. To make the engine more durable, Opel installed a water-cooled turbocharger that features an oil filter at the oil inlet point for reduced wear in the bearing system.
Opel designed the VGT and exhaust gas recirculation (EGR) module as a single system to attain optimal efficiency. Opel derived the EGR module from a new stainless steel radiator concept that offers a near 90-percent cooling efficiency. Meanwhile, an integrated, water-cooled EGR bypass valve help reduce pressure drop. Its closed loop control could dramatically improve NOx/PM trade-off under transient driving conditions as well as enhance the management of HC and CO emissions.
Engineers wanted the new 2.0 CDTI engine to boast of a consistent improvement in NVH attributes under all operating conditions. Thus, even before Opel built the first prototypes, the carmaker executed several CAE acoustic optimization loops on each engine component and sub-system.
Opel focused the architectural improvements on two high noise emitting areas of the engine: the top and bottom. This prompted the carmaker to use a new aluminum cylinder head design, a decoupled plastic cam cover with isolated fixings, as well as a sealing gasket. Furthermore, Opel wrapped the intake manifold in a single shell cover made from sound-absorbing material.
In addition, the carmaker fitted a new balancer shaft module -- made from high pressure die-cast aluminum -- at the bottom of the engine. This module accommodated two counter-rotating shafts that could offset up to 83 percent of secondary order engine vibrations. One of the balancer shafts -- geared to drive the other shaft – is driven by a helical gear on the crankshaft. Since scissor gear control guarantees seamless gear teeth meshing, Opel removed the drive chain to get rid of the risk of rattle noise. Following a detailed analysis, the carmaker opted to use plain bearings – instead of roller versions -- for the balancer shafts, resulting to lower levels of NVH and weight.
In addition, the oil pan now features a new design, with a two-piece solution replacing the single piece design. The new solution fixed a lower sheet metal pan to an upper section in high pressure, die-cast aluminum. Moreover, Opel improved the NVH performance of the engine through a number of analysis loops, allowing the carmaker to acoustically optimize the internal and external ribs of both sections of the oil pans.