A Calculation Methodology for Predicting Exhaust Mass Flows and Exhaust Temperature Profiles for Heavy-Duty Vehicles
Abstract:
The predictive control of commercial vehicle energy management systems, such as
vehicle thermal management or waste heat recovery (WHR) systems, are discussed
on the basis of information sources from the field of environment recognition
and in combination with the determination of the vehicle system condition.
In this article, a mathematical method for predicting the exhaust gas mass flow
and the exhaust gas temperature is presented based on driving data of a
heavy-duty vehicle. The prediction refers to the conditions of the exhaust gas
at the inlet of the exhaust gas recirculation (EGR) cooler and at the outlet of
the exhaust gas aftertreatment system (EAT). The heavy-duty vehicle was operated
on the motorway to investigate the characteristic operational profile. In
addition to the use of road gradient profile data, an evaluation of the
continuously recorded distance signal, which represents the distance between the
test vehicle and the road user ahead, is included in the prediction model. Using
a Fourier analysis, the trajectory of the vehicle speed is determined for a
defined prediction horizon.
To verify the method, a holistic simulation model consisting of several
hierarchically structured submodels has been developed. A map-based submodel of
a combustion engine is used to determine the EGR and EAT exhaust gas mass flows
and exhaust gas temperature profiles. All simulation results are validated on
the basis of the recorded vehicle and environmental data. Deviations from the
predicted values are analyzed and discussed.