in downsized engines even further. “We planned to develop a high-performance concept based on an engine from the mass market segment. It was essential for us to remain within the boundary conditions for series production and the same engine family,” Paul Kapus, Head of Gasoline Engine Development at AVL said, adding: “The module concept, in other words the ‘engine family stretch’, is explained by the fact that an entire engine family achieves both lower consumption and higher peak output levels. In addition to having common bore and stroke, the engines belonging to the same family also share the same cylinder spacing, the same cylinder head base design with the same flange positions and the same valve train. So, essentially, all of the basic dimensions are the same. As a result, all of the interfaces to the periphery remain unchanged too, both on the inlet and the exhaust side. However, these interfaces are also used to connect different kinds of turbochargers, for example,” 1 1 F O C U S Paul Kapus said, explaining the concept of modularity. ELECTRIC SUPERCHARGING SINCE 2002 To achieve the flagship model target of 200 kW/l in the engine family stretch, it is essential to provide additional charging because of the large turbochargers. Without this additional boost, torque and response behavior would not be acceptable at low engine speeds. Obviously, it should be the objective of a flagship engine to achieve a faster response behavior than the base model, and not just a high specific output. AVL realized this back in 2002 when the first prototype featuring electric supercharging was engineered. For that reason, a 48-volt-driven electric compressor was chosen to improve response and low end torque in the 200 kW/l concept. From 2006 onward, AVL developed the demonstration vehicle VW Passat Electric Boost Low Cost Hybrid. This concept demonstrated that a 2l TGDI engine fitted with a turbocharger and electric supercharging combined with a transmission with long gear ratios was capable of achieving fuel economy comparable to that of diesel engines in similar engine-power classes. The latest The current trends on the automotive market are very clear. Due to legal requirements and customer demands, engines in the mass market segment with moderate demands on performance must prove compliance with ever decreasing CO2 emissions. Conversely, specific torque and specific output in the flagship segment are showing a sharp rise, especially in the 2-liter class. The desire to replace six-cylinder engines with powerful four-cylinder engines, in particular, is leading to a sharp rise in specific output. Such high demands on output are creating an ever widening spread in the engine families. This calls for a high level of modularity. EXTREME MODULARITY FOR A BROAD POWER RANGE Engineering work on the 1.75-liter four-cylinder engine initially started when AVL teamed up with Fiat/ Alfa Romeo to develop the concept of a 330 hp (139 kW/l) engine for an Alfa Romeo Giulietta, which was unveiled at the Vienna Motor Symposium in 2013. Not long after, the implementation of several optimizations led to a further upgrade of the concept engine’s output to 350 hp (148 kW/l), which made quite a stir and generated a great deal of interest. At the time, the engine became known for having the highest output per liter under series boundary conditions. This achievement was topped by Volvo and AVL in 2014, when they presented their 450-hp 2-liter concept engine. Yet it seemed to the engineers that with 450 hp and two liters of displacement (168 kW/l) they had still not reached the limit, so in 2015, AVL decided to raise the power > Volvo S60 demonstrator vehicle with 450 hp engine. Photos: Pages 10, 12, 13 - Gerhard Langusch. Photo page 11 - Volvo Car Corporation.
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