Sustainability

Reducing the fuel consumption of vehicles is one of the most important issues today. Recently,
intelligent transport systems (ITS) technologies have been used to develop ways to reduce fuel consumption by avoid traffic congestion. In this paper, we propose an ecological route search that generates routes requiring the least amount of fuel by considering many factors such as traffic information, geographic information, and vehicle parameters. We report here on our fuel consumption prediction model and the results of comparative driving experiments using our ecological route search and conventional time priority route search methods. 

Hitachi Research Laboratory, Hitachi, Ltd.

Xanavi Informatics Corporation

NISSAN MOTOR CO., LTD.

Presented at the 15th World Congress on Intelligent Transport Systems, November 16-20, 2008, New York, New York

Traditionally the speed limit in urban areas has been 50 km/h, but recently in many cities and
towns it has been reduced even down to 30 km/h. This has been motivated especially by the
traffic safety, but sometimes we have also heard claims that it would reduce fuel consumption
and pollutant emissions, too. Driving slowly in a steady state means driving at low gears, and 
then the engine does not operate efficiently. On the other hand driving in urban conditions is
not only driving in a steady state, but the transient state dominates remarkably. Especially the
acceleration phase is fatal from the viewpoint of emissions and fuel consumption, and the
lower the speed limit is the less is the share of the acceleration phase in the vehicle motion.  

FinnRA

Presented at the 15th World Congress on Intelligent Transport Systems, November 16-20, 2008, New York, New York

This paper will present the implementation strategy for Intelligent Speed Adaptation (ISA) in Stockholm, and especially our goals and methods for combining ISA with functions for fuel saving and less emissions. As a basis for further ISA implementation, the City of Stockholm has tested active ISA in 20 vehicles. Speeding was reduced with 30% and the acceptance was good. After the trials, the City Council of Stockholm has decided that the goal is to have ISA in all vehicles driving for the City of Stockholm before 2010. An implementation strategy has been accepted which includes an ambition to exploit the possibilities of saving fuel and environment with ISA and also to use this as an argument for implementing ISA. A new concept for how to combine ISA with support for economical driving will be developed and tested in Stockholm. This concept is based on saving fuel by reducing speeding and improving economical driving. Speeding is reduced by the ISA-component and more economical driving will be achieved by combining support before driving (education, incentives), with support during driving (from vehicle computer) and support after driving (statistics, feed-back). “Ecodriving” is not a new concept - the new part is that we can use the ISA-equipment and the ISA-organisation also for ecodriving. This will make it easier and cheaper to implement both ISA and economical driving. The goal is to save at least 10 percent fuel and the corresponding amount of CO2.

City of Stockholm

Presented at the 15th World Congress on Intelligent Transport Systems, November 16-20, 2008, New York, New York

Today a rich amount of information about location, grade, and traffic speed
can be made available to a vehicle. It is proposed to use this information to design a smart
engine control strategy using predictive control that will trade off fuel economy versus
trip duration, with only minor hardware modifications. 
 
The predicted vehicle state and traffic information are used to determine a velocity
envelope that a vehicle may take over a given path. A predictive control strategy
optimizes the engine torque to trade off fuel consumption and trip time while keeping the
vehicle within a time-varying vehicle speed envelope. This paper presents the control
design approach and preliminary simulation results. The vehicle parameters used in
simulation have been provided by Audi, a premium brand of Volkswagen Group.

Volkswagen Group of America, Inc. Electronics Research Laboratory

University of California at Berkeley 

Presented at the 15th World Congress on Intelligent Transport Systems, November 16-20, 2008, New York, New York

In freight transportation vehicles are very heavy, especially in the Nordic countries of Europe.
Therefore the impacts on the fuel consumption as well as pollutant emissions are sensitive for
slight changes in the vehicle motion. The fleet itself is small compared to the one of passenger
cars, but due to the large size of the vehicles the energy need and emissions occupy an
essential share of the totality. In order to reduce the energy consumption and avoid climate
changes attention must be paid to way, how these vehicles are used. Truck drivers are in a key position, and they can affect the climate change by the driving technique. 
 
In case of a heavy duty vehicle the driving technique comprises two items, the (target) speed
selection and the gear shift strategy. The target speed is the speed, which the driver tries to
maintain any time when possible, but on upward slopes the speed naturally falls from the
target speed like 80 km/h, which is a typical legal speed in most countries of Europe. When
this slope ends, the vehicle will be naturally accelerated back up to the target speed. 
 
In the concept of the target speed there is also another factor, which does not appear in case of passenger cars or in general light vehicles. This is called a “schwung”, which means the
excess of the speed that can be utilized on downward slopes achieved by the gravitation. The
grade resistance is negative on downward slopes and causes high acceleration for a heavy
vehicle, and no fuel is consumed. The kinetic energy is increased and can be utilized on the
next upgrade. However, the “schwung” appears only, if the vehicle is heavy and the road must be hilly. Utilizing the “schwung” is one of the most efficient ways to save energy, although it is not legal, if the base target speed is equal to the speed limit.  

FinnRA 

Presented at the 15th World Congress on Intelligent Transport Systems, November 16-20, 2008, New York, New York