Vehicle Driveline example

Objectives

• Simulate a system comprising both linear and rotary mechanical components

• Use a duty cycle defined by the contents of an ASCII file

The system sketch for this exercise is shown below.

Figure 82: Sketch of the system

This is a very simple model of a complete car driveline and is set to model a hill start. Note that:

• A manual clutch is modelled using MECFR2R0A.

• The submodel WTX02 is a transformer between rotary and linear motion and models the differential, drive shafts and wheels.

• The inertia of the engine and gearbox are model using MECRL0.

• The system is built in such a way that the arrows in linear components and rotary components all point in the same direction. You should always try to obey this rule. If you break this rule, you may have to use negative gear ratios to get things working correctly.

• There are three duty cycle submodels used:

CONS0 which gives a constant value and is used to define the axle ratio.

UD00 which allows you to define piecewise a linear profile which is used to define the engine torque.

SIGUDA01 which takes a profile from an ASCII file and is used to define the operation of the clutch.

You could replace the SIGUDA01 submodel with another instance of UD00 but with SIGUDA01 you see how to use the Table Editor to create a data file. It would be easy to develop this model to be more accurate and realistic but it is a good principle in simulation to start with a simple situation and introduce additional complexity only if necessary to obtain realistic results. Open this system after copying it from the Simcenter Amesim Run demo area. It is called DriveLine.ame.