A method for estimation of average engine fuel maps: power measurements at drive wheels

Ulf Hammarström
Mohammad-Reza Yahya

There is a need for engine maps in order to simulate fuel consumption for road vehicles after mechanistic principles. In an engine map, fuel consumption (g/kWh or g/s) is expressed as a function of engine speed and engine torque. In general, there is a considerable lack in engine map data. The main purpose of this study is to develop a tool for assigning any segment of the car fleet a representative engine map. Two methods have been developed: a "matrix" method based on interpolation of measured values to a uniform grid of values and a "function" method based on regressions. The function alternative is in focus in this documentation. The estimated functions have a high degree of explanation (>0,97). On commission of the Swedish Road Administration, Rototest AB has measured stationary fuel consumption and exhaust emissions for more than 400 cars of different year models. If this data set could be used in mechanistic simulation models one could expect increased representativity in different applications. Advantages with the Rototest method, where the engine at measurements is mounted in the vehicle, could be increased representativity and lower costs compared to motor test bench, which is the traditional method for engine map measurements. One problem with the Rototest data set is that engine torque or power, which is needed in an engine map, is not available, only the output power from the final gear box. In order to estimate crankshaft torque, transmission losses need to be estimated.



Cost Benefit Analysis (CBA) workshop in Stockholm

An open seminar and workshop in Stockholm will be held on 25-26 April 2018. The workshop deals with the use of CBA as a basis for decision-making in the public sector. The workshop is organized by, among others, Professor Jan-Eric Nilsson, VTI.



Ulf Sandberg has been presented with the TTI Lifetime Achievement Award 2018

VTI’s Senior Research Leader Ulf Sandberg has been presented with the TTI Lifetime Achievement Award 2018 for his work on research into tyres and road surface.


Steps need to be taken to increase traffic safety of automated cars

Several steps are necessary to ensure that automated and connected cars will lead to increased traffic safety – everything from ensuring that technology takes vulnerable road users into account, to new forms of driver training. This has emerged in a position...


FALCON examines challenges in the transport sector

VTI is one of several important partners in the major FALCON project*, whose purpose is to create knowledge and insight regarding the transport sector. In an initial subproject, VTI has produced a manual on transport, logistics and multimodality.


VTI joined research cooperation in China

In December 2017 VTI became a member of China-Sweden Research Centre for Traffic Safety (CTS).


Swedish German research collaboration on Electric Road Systems

The project “Swedish-German research collaboration on Electric Road Systems” (CollERS) has now officially started. The goal of the project is to increase the common knowledge around Electric Road Systems by cooperation between Germany and Sweden and to...


Electric Road Systems Conference 2018

After a successful first conference in June 2017, the Swedish research and innovation platform for electric roads is arranging the second dedicated International Conference on Electric Road Systems (ERS) June 13th and 14th 2018.