Browse Publications Technical Papers 2005-01-0406
2005-04-11

Streamlining Chassis Tuning for Chevrolet and GMC Trucks and Vans 2005-01-0406

This paper describes some methods for greatly reducing or possibly eliminating subjective tuning of suspension parts for ride and handling. Laptop computers can now be used in the vehicle to guide the tuning process. The same tools can be used to select solutions that reduce sensitivity to production and environmental variations.

OBJECTIVE

Reduce or eliminate time required for tuning of suspension parts for ride characteristics. Improve the robustness of ride performance relative to variations in ambient temperature and production tolerances.

PROBLEM REQUIRING SOLUTION AND METHOD OF APPROACH

Traditional development programs for new vehicles include time-consuming subjective ride evaluations. One example is shock absorber tuning. Even if sophisticated models define force-velocity curves, numerous hardware iterations are needed to find valvings that will reproduce the curves. Many evaluation rides are needed to modify the valvings to meet performance targets. If there are multiple ride packages, the process must be repeated. If the valvings result in validation concerns, more iterations may be needed.
With the increasing power of spreadsheet software (such as Microsoft Excel®), it is now possible to quickly predict shock valvings for the target force-velocity curves. By varying leak coefficients, fluid viscosity, friction, and other elements of the model, the robustness of the selected valvings can be evaluated. Finally, if models are created for different types of shock absorbers, they can be used to determine which type of shock (monotube, twin tube, deflected disc, blowoff, etc.) can come closest to matching the target force-velocity curve.
Data shown includes target curves, predicted curves, and test data for sample valvings in one type of shock absorber.

CONCLUSIONS

Spreadsheets and other tools can be used to reduce subjective evaluations and greatly shorten development time required for new products. The time between evaluations can be reduced significantly when the next valve settings are determined before returning to the garage by using a laptop computer in the vehicle. The results not only are achieved more quickly, but also are more likely to meet durability and other downstream requirements.

SAE MOBILUS

Subscribers can view annotate, and download all of SAE's content. Learn More »

Access SAE MOBILUS »

Members save up to 43% off list price.
Login to see discount.
Special Offer: With TechSelect, you decide what SAE Technical Papers you need, when you need them, and how much you want to pay.
X