Application of Coulomb´s friction law to define energy consumption of new drive-trains

A key argument in the transport field is about improving the energy consumption of cars. Should we go electric, ban combustion, move to fuel cells or change to renewable fuels [1-5]? This is an important research question because the number of cars worldwide is predicted to grow from 0.7bn in 2010 to 2bn in 2050, leading to a huge penalty in fossil fuel depletion, climate change and energy security in the near future [6]. But these discussions of electric cars, new battery materials and renewable fuels have missed a key point:that the main difficulty with cars is their evolution in terms of increasing weight. Evidence shows that cars increase in weight by about 2% per annum. This paper demonstrates that car weight dominates the energy question by showing that Coulomb´s law of friction surprisingly applies to a complex system like a car, such that the energy usage, in other words overall friction force, depends mainly on weight. A new theory shows that dissipation in complex systems resolves into Coulomb´s Law. Experiments demonstrate that the results fit this theory reasonably well. We have tested a hydrogen fuel cell battery hybrid composite car of 7kN weight and present results better than all existing hydrogen cars in terms of low energy use. The conclusion is that Coulomb´s Law can be used to quantify precisely the energy consumption of cars and that lightweight designs are as important as hydrogen electric drive-trains in cutting fuel consumption.