Project: ELinGO - Electrification of heavy freight transport. Work package 3

The purpose of WP3 is to develop a model for calculating power and energy requirements for vehicles. It should cope with different vehicle types and configurations, and use factors we know affects the results, such as road topography and speed profile. Much of the literature in this field refers to vehicle energy requirements in litres per km, or Mega Joules (MJ) per km. The problem is that this information is valid only for one vehicle doing one specific drivecycle. Any changes in topography, speed profile, weight or other factors will give other results. These numbers cannot be transferred to other situations, and this is a problem when looking at the effects of changes in road geometry, driver behaviour and vehicle improvements. By changing the focus to more fundamental factors like geometry, speed profiles and drivetrain efficiency, a more adaptable model can be developed. The simplest approach to calculating a route in more detail is to analyse each road segment by itself, assuming constant speed and load, and then add all results. In many cases this is fine, but the method hides the real utilization of engine and brakes (including regenerative brakes), and will not produce a realistic speed profile. The method described here uses output speed from one short segment as input speed to the next short segment. This assures that the effects of varying speed preferences and road geometries can be expressed. Speed profile and engine/brake load along geometrically equal road segments will vary a lot with the properties of the preceding segments, being uphill, downhill, roundabout or other, so the ordering of segments is important. The recent improvements in national roads databases and speed preference models make such a detailed calculation model both possible and practical. Besides better calculations of total energy and fuel consumption, it is also possible to see where along the route fuel is spent. This information is important for assessing the need for charging of electric vehicles but could also be useful for studying local emissions and noise.