GME GME16200 PDF

Introduction

Note: Nothing in this standard supersedes applicable laws and regulations.

Purpose. Primary aim of this test is to measure in-car the drag torque of the drive train as a function of speed in neutral gear.

As a welcome side-effect also the inertia of the drive train is an intermediate result of the evaluation.

Foreword. Transmission drag in neutral is a subset of the total vehicle road load.

The vehicle road load is a prerequisite to run emission and fuel consumption tests (e.g. for type approval) on a roller dynamometer.

The road load is usually determined by vehicle coast downs on a proving ground. By means of spin down test results the number of required vehicle coast downs can be reduced to at least 1 drive train variant per carline. The remaining variants are calculated by subtracting and adding the drag torque of different drive trains from / to the road load of at least 1 available vehicle road load.

Beside of that the drag torque is an adequate indication for the efficiency / losses of a transmission. But as a matter of course the spin down test is not a substitute for a transmission efficiency map, since it is conducted without torque transfer (gear = neutral).

Applicability. All vehicles with a mechanical drive train.