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

Micro Gas Turbine Range Extender Performance Analysis Using Varying Intake Temperature

A micro gas turbine (MGT) can potentially be an alternative power source to the conventional internal combustion engine as a range extender in hybrid electric vehicles. The integration of the MGT into a hybrid vehicle needs a new approach for technical validation requirements compared to the testing of an internal combustion engine. Several attributes of the MGT are predicted to cause concerns for vehicle sub-system requirements such as high ambient temperature and start-stop behaviour. This paper describes the results from specially developed experimental techniques for testing the MGT in a typical automotive environment. A black box MGT was used in this study for performance investigation during hot and cold starts. The MGT was instrumented and fitted with automotive standard components to replicate typical vehicle operational conditions. The intake air temperature was varied between 10 and 24 °C. A significant reduction in the power output of the MGT was observed as the intake temperature was increased. The proposed case scenario caused a reduction in nitrogen oxide emissions in the range of 0.02−0.04 g/km because of the lower combustion temperature at high intake temperature. However, hydrocarbon and carbon monoxide emissions have not shown a noticeable reduction during the power output degradation. The experimental results have highlighted the potential issues of using the MGT at higher intake temperatures and suggest design change to take the effect of higher engine bay temperature into account

Characterisation of micro turbine generator as a range extender using an automotive drive cycle for series hybrid electric vehicle application

This study investigated a micro turbine generator (MTG) as a range extender for a series hybrid electric vehicle application for a range of constant and dynamic power demand strategies. The power demands were calculated through a mathematical model based on a specific vehicle platform using the New European Drive Cycle (NEDC). The power demands were then used to characterize the MTG in a controlled test environment. Each of the strategies produced interesting results in terms of fuel consumption, specific emissions, net efficiency, and power responses. The experimental results revealed the lowest specific emissions, and fuel consumption while the MTG operated at constant power demand. One of the dynamic power demand strategies also produced low fuel consumption, but with higher specific emissions. Although exhaust emissions in each strategy were well below the Euro 6c limits. These results indicate the potential of MTG as a range extender in a series hybrid vehicle. Even, the MTG can be operated dynamically with relatively low fuel consumption and very low specific emissions, compared to the traditional approach of a constant power demand

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

Micro gas turbine range extender : validation techniques for automotive applications

A Micro Gas Turbine (MGT) can be considered as an alternative to the internal combustion engine as a range extender for electric vehicles. The MGT produces less raw exhaust gaseous emissions such as HC and CO in aerospace and static applications compared to the internal combustion engine. In addition, the MGT weight is less than an equivalent internal combustion engine and potentially can reduce the level of CO2 further in a vehicle application. However, the use of the MGT in an automotive domain has some unique technical and commercial requirements that will require new validation approaches. An air filtration system is known to be one of the important elements to characterise the performance and the emissions of the MGT. In the past, most of the efforts on MGT were focused on the vehicle development and packaging studies, where the technical requirements of the test standards for the air filtration system were not considered. Furthermore, the validation techniques of the air filtration system for automotive applications have different requirements to those of a large scale turbine for aerospace use. A test method has been developed to investigate the effect of the automotive air filtration system on the MGT’s characteristics in terms of the electrical power output and potentially the gaseous emissions. The outcomes of the research have provided good understanding of the MGT validation process in the automotive applications. It addresses the potential challenges that may hamper the MGT range extender for hybrid electric vehicle development processes