The European Automobile Manufacturers Association EAMA has made an obligation to reduce the average carbon dioxide emissions in new vehicles to 140 g/km by the year 2008. This corresponds to a fuel consumption of 6.0 l/100 km for gasoline passenger cars and of 5.3 l/100 km for diesel passenger cars.

Furthermore, examinations are currently being performed to see if an EU threshold of 120 g/km is achievable by the year 2012. Even lower CO2 emission levels of 90 g/km are being discussed for the year 2010 by the EU in accordance with the goals of the Kyoto Accord.  

If you assume an average CO2 emission value of about 190 g/km in Europe, then you can see which technical developments are necessary to achieve these high goals. An increase in the percentage of diesel passenger cars in the fleet of passenger cars in Europe definitely has a positive effect on the CO2 emissions, but this alone will not lead us to the goal. Emphasis must be placed in development on improving the most commonly used drive unit, the gasoline engine, with respect to its efficiency and emissions. Considering the fact that 75% of all vehicles in Europe are driven by gasoline engines, the greatest effect would be gained by improving this engine design.
 
One of the most promising measures to reduce fuel consumption is downsizing. In this concept, large displacement, naturally aspirated engines are replaced by supercharged engines with small displacements and fewer cylinders. Downsizing leads to a shift in the load points of the engine operating points into areas of higher efficiency.

Smaller, more compact engines with fewer cylinders also have lower losses due to friction and are lighter than naturally aspirated engines with the same performance. Reductions in consumption of up to 20% can be achieved through consistent downsizing. Currently, engines with 3 or 4 cylinders and cylinder capacities between 0.6 and 2.0 liters are being discussed. The output density can vary between 60 kW/l and 100 kW.

 
The newest generation of charging systems from Junfeng Turbo Systems will therefore need to fulfill even higher demands than has been the case so far.  
 
• In future gasoline engines the demand for charging pressure will increase and the air flow  rate range will expand. The startup torque of the small displacement engine can be improved through the use of variable turbines (VTG or VST), Boosters or multistage charging systems.   

• The exhaust temperatures of future turbocharged gasoline engines will increase. The air  ratio at the rated output point is currently about λ=0.75-0.85 since a portion of the fuel is used to cool the inside of the engine. If the air ratio is increased to a value between λ=0.9-1.0, then a potential fuel savings of up to 20% can be attained. The exhaust temperature will rise by about 50 to 100 K depending on the air ratio.
 
• The thermal inertia and the surface area of the turbine housing are to be kept as small as  possible to keep emissions low. A reduction in the weight in this context also benefits the total weight of the vehicle.