Development of classic powertrains
Conventional vehicles still determine the look of our roads – and with good reason. Modern vehicles are extremely clean, use the energy of their fuel frugally and convert raw energy into the necessary propulsive power in extremely efficient ways. The result is impressive. This year, the Euro VI standard came into force for heavy commercial vehicles. From September this year, the Euro 6 exhaust standard will be binding on new type-tested passenger cars for the first time; one year later, it will apply to all newly registered cars. This means pollution emissions can be reduced by about 95 percent compared to Euro 0.
The NOX and particulate emissions that are in the public eye have been significantly reduced over recent years in particular: 80 percent NOX reduction and 50 percent particulate reduction from trucks in the last level alone (i.e., compared to Euro V). As far as cars are concerned, the 80 percent particulate reduction has already been implemented with Euro 5. In Euro 6, it is now the NOX emissions above all that are being reduced by a further 56 percent.
As far as efficiency is concerned, the conventional powertrain has undergone impressive development. The statistics relating to improvements in the efficiency of German automobiles speak for themselves. Internal combustion engines account for a large proportion of these improvements as their consumption and emissions values continue to fall year on year. The latest generation of petrol engines featuring displacement downsizing and supercharging, direct injection, stop-start technology and intelligent thermal management result in savings of almost 30 percent in fuel consumption over comparable conventional vehicles with a naturally aspirated injection engine and no charging system.
The results with diesel are similar. The direct-injection diesel engine with turbocharging is regarded as the state of the art. The latest generation of diesel engines features fewer cylinders and a smaller displacement, high-pressure multiple injection, higher charging, stop-start technology and intelligent thermal management. Overall, this means fuel savings of around one-third compared to the classic turbo-diesel engine.
A particularly frugal model of a modern, practical family car in the compact category with appealing driving performance and a propulsive output of 81 kW currently achieves average fuel consumption of as little as 3.2 l/100 km. This is made possible by a host of measures in the vehicle and powertrain: latest engine technology and optimization throughout every single ancillary unit: Low-friction valve trains, efficient alternators and oil pumps, electric servo pumps and high-efficiency, intelligent gearboxes. Most of these important components are from German components companies.
Classic optimization measures are approaching their limits, as a result of which increasing hybridization of vehicles is becoming more and more important. In principle, hybrid drives permit braking energy recuperation and a significantly greater level of system optimization. This makes it possible to tap new efficiency potential, which cannot be achieved with conventional powertrains alone. However, hybrid drives weigh more because of their additional components, something that has the effect of increasing consumption at higher speeds. On the other hand, this additional consumption can be more than compensated by the further optimization potential offered by the hybrid drive. Particularly during urban driving (stop/start, lots of part-load driving), a full hybrid can lead to consumption savings of more than 30 percent. The hybrid is now part of the standard product range offered by German manufacturers, whether in the compact, medium or upper categories. It is also represented in the sports car segment. The German automotive industry is a global producer and development partner of hybrid components and systems.
In spite of increasing electrification, an internal combustion engine will remain the principle source of energy in the hybrid in the future as well. As a result, optimization of the conventional powertrain remains a key task of development departments at German manufacturers and components companies. In future, indeed, 80 percent of cars will have an electric drive, but at least 80 percent of future cars will also continue to have an internal combustion engine. Only fully electric vehicles (BEVs) as well as fuel cell vehicles can dispense with an internal combustion engine.