Method and arrangement for determining the remaining driving range in an electric vehicle

摘要

The invention relates to a method for determining the remaining driving range in an electric vehicle with accumulator battery, the energy E removed during a discharge being measured. In addition, for the accumulator battery a characteristic curve which fixes the available charge Qvert for a predetermined discharge current with the available charge Qvert as ordinate and a discharge current as abscissa. When the electric vehicle is travelling, the current removed from the accumulator battery is measured and and integrated over the driving time with the aid of an integrator. From this, the average value I of the power drain is formed with the aid of an average value former. In accordance with the characteristic curve and the average value I of the power drain, the available charge Qvert and the available energy Evert are initially determined and with the aid of two subtractors the remaining energy ERest is determined from the available energy Evert and the energy E already removed and the remaining charge QRest is determined from the available charge Qvert and the charge Q removed. In addition, the power removed from the accumulator battery during travel is measured. It is integrated over the driving time with the aid of an integrator. From this, the partial amount of energy Edt corresponding to a last travel time interval dt is formed with the aid of an adder. This value is constantly updated with an updating period which is small in relation to the specified travel time interval dt. In addition, the path Sdt covered in the travel time interval is measured. From this, the quotient Sdt/Edt is formed with the aid of a divider. This quotient is multiplied by the remaining energy ERest with the aid of a multiplier - and this variable is used as a measure of driving range. In general, it is sufficient to operate with a travel time interval dt which constitutes approximately 10 minutes for determining the specific energy consumption and constitutes the entire travel time since the start of discharging for determining the remaining range, whilst the updating time is 30 seconds. IMAGE