Application of Air Suspension System on Multi-purpose Forest Fire Fighting Vehicle for Reducing Dynamic Load

PurposeDuring operation, dynamic load from the road surface acting on the vehicle affects the dynamic safety of the vehicle. Therefore, it is necessary to research solutions to reduce the dynamic load of the multi-purpose forest fire fighting vehicle. While the active and semi-active suspension system equipped on the vehicle has not been effective compared to the price, the optimal solution to reduce the current dynamic load is to replace the traditional suspension using springs with the air suspension system. This research aims to replace the leaf spring suspension of a multi-purpose forest fire fighting vehicle with an air suspension system in an effort to lessen the vehicle's dynamic load.MethodsBy building a dynamic model of the vehicle according to the method of splitting the structure of the multi-body system (MBS) and the Newton-Euler equation, in which the binding force between the suspended and unsuspended masses is described by two submodules are "leaf-spring" and "air balloons". Use this model to investigate the influencing factors including vehicle speed and road type on the dynamic load of the vehicle. The results of the study were carried out on the road type in accordance with ISO 8608:2016 to estimate the DLC value for vehicles utilizing spring suspension and air suspension to evaluate the level of decrease in dynamic loads placed on the vehicle.ResultsThe survey results of the model with two types of suspension systems compared show that when using an air suspension instead of a metal suspension (leaf-spring) on a multi-purpose forest fighting vehicle, the dynamic load can be reduced up to 19.6%, contributing to reducing the impact load on the vehicle.ConclusionsThe author has conducted research and analysis on the capability of reducing dynamic loads based on road type and speed, and evaluation according to DLC criteria. According to the findings, automobiles equipped with air suspension systems perform significantly better; according to ISO 8608:2016, when a vehicle is moving on a road of class A, B, or C, the vehicle is not limited in speed but nevertheless ensures road-friendly criteria. This ensures the detailed durability and dynamic safety of the vehicle. Class D roads are restricted to a maximum speed of 15 km/h, which helps to meet the aforementioned standards, Even with the air suspension system, the vehicle fails to achieve the road-friendly criteria necessary to guarantee its detailed durability and dynamic safety when driving on extremely poor roads (class F), but wheel separation appears narrower than leaf spring suspension.