Modelling of 4WD vehicle driveability during tip-in/tip-out events

This paper describes a modelling method to investigate the dynamic behaviour of 4WD vehicle under a severe driving condition, where the driver applies a rapid tip-in on the accelerator pedal in 2nd gear to achieve maximum engine torque. This is followed by a tip-out event by releasing the accelerator quickly. The Tip-In/Tip-Out events are one of important elements to assess the vehicle driveability. During these test events, the vehicle is expected to generate low frequency vibration between 2 Hz and 10 Hz and gives discomfort feelings induced by resonance effects on sensitive human organs. The aim of this paper is to develop a 4WD vehicle model in a modern object-oriented multi-body simulation tool and study its driveability

Shuffle frequency migration of 4WD vehicle

This paper explains the method to examine the driveability of Four Wheels Drive vehicle. One of key elements to assess the vehicle driveability is to expose the vehicle under harsh driving conditions such as feeding the crankshaft with wide open throttle torque within a short period of time. As a result of this abrupt torque excitation, the vehicle is expected to generate low frequency responses and deliver discomfort feelings induced by resonance effects on sensitive human organs. Understanding the interaction across vehicle component levels is imperative to address the root cause of driveability issues. Frequency migration analysis was carried out to determine the prevailing factors and sub-system components that control this occurrence. Matrices consisting of a range of frequencies have been structured and analysed to precisely pinpoint the sensitivity of vehicle shuffle frequency migration based on different operating mode

System modelling and analysis of the driveability response of 4WD vehicle

This paper presents a system modeling approach for examining the driveability of Four Wheels Drive vehicle. One of key elements to assess the vehicle driveability is to expose the vehicle under harsh driving conditions such as feeding the crankshaft with wide open throttle torque within a short period of time. As a result of this abrupt torque excitation, the vehicle is expected to generate low frequency responses and deliver discomfort feelings induced by resonance effects on sensitive human organs. Understanding the interaction across vehicle component levels is imperative to address the root cause of driveability issues. Frequency migration analysis was carried out to determine the prevailing factors and sub-system components that control this occurrence. Matrices consisting of a range of frequencies have been structured and analysed to precisely pinpoint the sensitivity of vehicle shuffle frequency migration based on different operating mode

A low fidelity non linear model of 4WD torsional stiffness at tip-in/tip-out

This paper describes the effects of torsional stiffness in the vehicle drivetrain on 4WD vehicle drivability during transient drive events. The approach uses acausal modelling methods to create a low fidelity torsional stiffness model for a 4WD vehicle during tip-in/tip-out events in response to torque inputs. The torsional response during these events is one of the key elements to assess the vehicle driveability. The paper focuses on the torsional frequencies in the range of 2Hz to 10Hz, where the human body is very sensitive to oscillation modes. The low fidelity model is correlated with a full nonlinear model. Real time simulation is included in the experiment to validate the response of the torsional model in real time test