What are the main methods of chassis tuning?

Main methods of chassis tuning

Automobile companies have always regarded chassis tuning as their specialty, and the complexity and difficulty of the technology are self-evident in the process of vehicle performance development. Automobile performance is generally evaluated by evaluation indicators such as power, fuel economy, braking, handling stability, smoothness and passability. Vehicle tuning mainly carries out corresponding work around these indicators. The chassis tuning mentioned generally refers more to how to improve the overall performance of the chassis and ensure the best balance between comfort and handling during the chassis performance tuning process.

For a car to have good steering performance, handling stability and driving comfort, on the one hand, the overall structure of the vehicle should be optimized during design to have good K&C performance, which involves the design of the hard points of the suspension system, steering characteristics, wheel alignment parameters, etc. On the other hand, it involves the development and matching of components and systems such as springs, stabilizer bars, shock absorbers, tire bushings, and steering systems.

The methods of automobile chassis performance tuning include virtual tuning and subjective tuning. Among them, the virtual tuning method is low-cost and high-efficiency, while the subjective tuning method uses human senses to ultimately confirm the perceived quality of the product.

01Subjective Adjustment Method

Usually, the subjective evaluation scoring system divides performance equivalence into 10 levels, with the best getting 10 points and the worst getting 0 points. The scores are presented in the form of a butterfly chart.

Figure 2 shows the subjective evaluation results of a certain model before tuning, the evaluation results of the bidding car, and the target value that the model is expected to achieve. The ultimate goal is to narrow the gap between the model and the bidding car, and make the subjective evaluation score of the model not lower than the target value after the tuning is completed.

Figure 2 Evaluation results and target setting values ​​of a certain model and bidding models

02Virtual Adjustment Method

Subjective evaluation methods have limitations that are difficult to quantify. Automobile companies will use some commercial software to model the entire vehicle as a virtual prototype and complete model calibration to conduct qualitative verification of the tuning results. Commonly used software include multi-rigid body dynamics software Adams/car, carsim, etc.
Standards such as "Automobile Handling Stability Test Method". The important research object in chassis tuning is the suspension, and the K&C performance of the suspension is a concept that cannot be ignored.

K&C performance: K stands for Kinematic,
which means the wheel movement related to the suspension linkage without considering the movement of force and mass; C stands for Compliance, which means the wheel movement related to the deformation of the springs, rubber bushings and components of the suspension system due to the deformation caused by the applied force.

The K&C test of the suspension system simulates the suspension movement caused by road excitation on the test bench.