Transient Modeling for Heavy Tracked Vehicle Performance and Fuel Consumption under Accelerating Conditions

A personal computer-based transient simulation model has been developed to predict heavy tracked vehicle performance and fuel consumption under accelerating conditions. The model consists of a transient engine model, a transient powertrain model and a driving resistance model. Engine dynamics, turbocharger dynamics and governor dynamics are related with throttle position, clutch pedal and gear lever, and the effects of these factors on vehicle transient behavior are formulated. Engine transient performance is calculated based on the cycle by cycle analysis of engine running processes.

The computer simulation has been implemented for a 5-speed manual-transmission heavy tracked vehicle, and is validated by comparing the predicted values with the measured data.

The vehicle accelerating performance and fuel consumption have also been calculated by using the engine maps based on the steady-state experiments. The underestimation for the vehicle acceleration duration and fuel consumption is shown. The overall results have demonstrated the developed transient model is a useful tool. It can be applied conveniently in analyzing and predicting heavy tracked vehicle transient characteristics with a satisfactory accuracy in the early stages of the heavy vehicle design.