1. Suspension Tester Specification
SWG6 UPDATE
AICA 14/11/2017

2. "Adhesion alone is not adequate for the conclusive evaluation of shock absorbers. The phase angle is a function of the damping value at different frequencies and should be used for evaluation of the damper performance. ...“ SAE Technical Paper , 1996, Tsymberov A.
Eusama needed improvements because of:
New super light city vehicles
Vehicles with Run Flat Tires
Vehicles with very low profile tires
Some heavy vehicles which succeded the test despite a bad working damper
-> Recent developments in the vehicle industry had their influence on parameters like tire rigidity and unsprung mass
-> These parameters influences the road adhesion by consequence also the Eusama value
Frequency-domain response:
magnitude response ("road adhesion"): indicative to vehicle safety, unreliable for dampers
magnitude + phase response ("phase shift"): vehicle safety AND dampers condition

3. Phase shift φ
The minimum phase shift φmin is the lowest value of the phase shift φ determined during the test between the sprung and unsprung mass resonant frequencies.

4. Phase shift φ
The phase shift φ = the angular difference between the absolute “sinusoidal” position of the suspension tester platform & the “sinusoidal” vertical tire contact force between the tire + the suspension tester platform..

5. Test bench specifications
Metal plate designed for vibrating in the range of [25 - 5] Hz with a peak to peak amplitude of 6 mm
Weight measuring points per plate
Sensor to detect the plate’s vertical position
A drive of the frequency variation in order to have a more correct measurement by dissipating more energy in the proximity of the unsprung mass resonance frequency (min 7 sec).

6. Influence of the stroke of measuring plate

7. Influence of the Sprung Mass (car body)

8. Influence of the Tire Rigidity
Influence of the Tire Rigidity !!!!! cases with even negative Eusama have the Minimum Phase Shift still above 35°

9. Influence of the main spring

10. Influence of the Unsprung Mass (wheel)

11. GOCA 2010 spec. doc CEN standard compatible format
Removed references to EUSAMA and GOCA
EUSAMA replaced by max force amplitude unbalance
Removed details to specific implementations (e.g. Inverter). «What vs How»
Deep analisys of each technical details nothing missed or misunderstood
Redefined absolute and relative criterias
TBD Approval procedure & Calibration procedure
TBD Calibration tool & Who will certify it

12. Calibration tool from VIAS institute (www. vias
Calibration tool from VIAS institute ( TBD the Egea ones, VIAS seems not interested in selling his solution

13. Goals Without ambiguity, everyone can make their own bench
Add basic raccomandation about the system should work
Convince the European commission from a nice to have to mandatory

14. 4 key reasons to adopt it EU-wide…
Single test method applicable across all European Member States for roadworthiness testing
Minimum change to existing installations of suspension tester design/specification or for new installations
Minimised costs due to a higher volumes of existing design and functions
Existing GOCA database of test results ensures benchmarking (from 2011 ~25M vehicles tested)