DEVICE FOR ESTIMATING VEHICLE MASS

PROBLEM TO BE SOLVED: To provide a device for estimating vehicle mass capable of accurately estimating the vehicle mass with a simple and inexpensive constitution. SOLUTION: This device for estimating vehicle mass obtains vehicle estimation mass (gear-shift-time vehicle estimation mass) dRWM estimated based on the vehicle acceleration before start of the gear shift operation (state where a driving force is transmitted to a driving wheel) and the vehicle acceleration during the gear shift operation (state where no driving force is transmitted to the driving wheel), averages the obtained gear-shift-time vehicle estimation mass dRWM (refer to another routine of Fig. 3), estimates the slope of the vehicle travel road surface based on the averaged gear-shift-time vehicle estimation mass RWM (S3 and S4), substitutes the estimated gradient into a mass formula of acceleration expression to obtain the vehicle estimation mass dMAM (S9 and S10), averages them to obtain an average MAM (S12), and hence makes the vehicle estimation mass close to the true value (S15). Therefore, even when the chance of gear shift is small, the vehicle mass can be estimated accurately. COPYRIGHT: (C)2008,JPO&INPIT