At least one can rely on the petrol pumps. If you fill up, e.g., with 45 litres, then they have been run through a certified measure, which is probably quite regularly checked. Ok, in winter you get a little more mass than in summer, which improves your fuel consumption very slightly, indeed, the manufacturer can do nothing about that.
When buying a car, this is increasingly no longer the case. If the prospectus maintains, that the car has a fuel consumption of 4,8 l/100 km, in reality it can be as much as 50% higher. The only value that you can count on, is that a petrol driven car has an even higher consumption.
'Der Spiegel' (a German magazine) printed a report about the special tricks used. They mention test tracks, which have a downhill slope that is just inside the allowed regulations and tyres, which have been specially prepared to give a low consumption. For a long time now, we know all about intelligent engine-management, which recognizes test situations and handles the expensive fuels accordingly.
It's not only the favourable consumption the manufacturers have in mind, but the linked thereto CO2-value. This is something that's giving the German manufacturers headaches, with their large, heavy cars. They have at least managed, at the end of 2013, on straight, flat roads, to achieve an average value of 130g/km, which was the target for 2015, and this value will still be substantially reduced. You can read more about this here.
VW Passat 2.0 TDI Old: 4,6 l/100km at 103 kW (140 HP) New: 4,0 l/100km at 110 kW (150 HP) Do you believe this?
The last few percent, as far as consumption reduction is concerned, are more difficult to achieve. Thus the clearly falling value, down to less than 95 g/km in 2002, could more or less level out, there are however, a number of ways in which the manufacturers can be helped along, e.g., by the respective government. Politics had e.g., provided the wondrous thriftiness of hybrid vehicles, whereby the first battery-charging was not considered in the equation. It would help the manufacturers if more vehicles like this were to be sold.
Pure E-mobiles will be given even more Super-Credits.
The manufacturers themselves, have also found loop-holes, for example, the start-stop automatic, which in the meantime, they can install in nearly all cars. In real life traffic situations however, their usefulness is limited. One is always unsure, whether the chance to drive on will arise, exactly then when the engine cuts out. Indeed, in the standardised driving cycle there are currently 13 (!) situations where this feature can be sensibly applied. Not only for this reason, are urgent changes in the testing necessary.
The hope of finding a more practice-orientated test method will be the last thing to die. What, at the end of the day, is more reliable in politics than lobbying. Then, when the testing is done according to the Worldwide harmonized Light vehicles Test Procedure, the legal departments and the engineers will be combing through the directives to find loop-holes, and they will use all the tricks in the book. We will nevertheless, be another step further.09/14