EPA and NHTSA have harmonized Regulations for Greenhouse Gas
(GHG) emissions and Corporate Average Fuel Economy (CAFE) for model
year (MY) 2012-16, published on April 1st, 2010. This requirement
applies to all passenger cars and light trucks. Therefore the
reduction of CO₂ emissions will be a major challenge for the
automotive industry in the coming years to achieve the targets (GHG
& CAFE) of 250 g/mi CO₂ and 35.5 miles per gallon (mpg) for MY
2016. In addition to combustion engine improvements, vehicle energy
management and operating strategies offer a huge potential to
reduce CO₂ emissions through innovative electronic systems.
The paper will show a possible implementation of a holistic
vehicle energy management system including the operating strategy
"Free wheeling." Starting from a top-down approach, we
have developed operating strategies that offer the possibility to
optimize the energy usage of the entire system. Energy recuperation
and advanced Stop/Start system are the main elements of the
operating strategies.
Design of new power net architectures is necessary to tackle the
requirements of the new systems. To achieve the same level of
reliability the vehicle systems and components must be adapted
accordingly to allow engine stop for vehicle speed not equal to
zero. The evaluation of the energy management strategies are based
on a "virtual" average CAFE passenger car. This vehicle
is investigated in simulating the driving cycles FTP-75 and HWFET.
The feasibility of the 35.5 mpg target will be shown.