Analytical Traction and Propulsion Analysis

Conventional approach for vehicle traction and propulsion analysis used spreadsheets. This is inconvenient if one intends to vary a parameter, and it is even more difficult when multiple parameters are evaluated at the design phase. In this paper, it is intended to formulate two nonlinear differential equations representing road load and power consumption. By expanding inertia force, air drag, rolling resistance, gravitational force and tire tractive force, the equations can be simplified as the function of velocity v, i.e., s1 v̇ = s2 - S3V2 and mv̇ = -r1v3 - r2v + r3/v, respectively. With these two equations, it allows engineers to use either numerical or analytical method to study key parameters at the design phase. To demonstrate the effectiveness of these equations, Wright State's electric car model is used. The results for front-wheel drive (FWD), rear-wheel drive (RWD) and four-wheel drive (4WD) cases are presented.