Simulation and Optimization of the Longitudinal Dynamics of Parallel Hybrid Railway Vehicles - Forms/Format 2010 - page 157

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Fig. 1. Simulation structure for a parallel hybrid railway vehicle.

by the torque which is necessary to follow the duty cycle. Additionally, fuel
consumption, NOx -and PM emissions are determined. The way how the
electrical part (consisting of the electric motor/generator, the energy stor-
age device, and the electrical auxiliaries) is used, depends on the operating
strategy to be optimized in Sec. 3.

2.1 Forward and Backward Calculation on the Vehicle

In Fig. 2, the block of the vehicle subsystem and its interface variables are
depicted. The different kinds of arrows again indicate the direction of the
forward and the backward calculation, respectively. The inputs of the forward

Fig. 2. Interface variables of the vehicle model.

calculation match the outputs of the backward calculation and vice versa. The
braking force F brake , however, is considered as an additional driver input for
the forward approach only. The mathematical model in this paper is restricted
to the longitudinal dynamics because the lateral dynamics do not have an
important influence on the optimization task to be performed. In the forward
calculation, the corresponding force balance can be stated as

m veh a veh = F wheel − F brake − F res − F inc . (1)

Here, m veh represents the total vehicle mass. The force F wheel acting at the
wheels is related to the torque T wheel at the wheel and the wheel diameter
d wheel according to

F wheel = 2

T wheel
d wheel

.

(2)