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The Challenges of Electrification in Premium Luxury Vehicles

2012-03-27
JLR is on track to develop stop-start, parallel hybrid and plug-in parallel hybrid vehicles in the next few years. Plug-in hybridization is arguably the most suitable technology for large, premium luxury vehicles for the foreseeable future. Range_e is a UK based demonstrator for a plug-in hybrid system and has brought into sharp focus the attribute issues and wider challenges that need to be taken into consideration when moving towards production. Presenter Paul Bostock, Jaguar Land Rover
Technical Paper

Complete Body Aerodynamic Study of three Vehicles

2017-03-28
2017-01-1529
Cooling drag, typically known as the difference in drag coefficient between open and closed cooling configurations, has traditionally proven to be a difficult flow phenomenon to predict using computational fluid dynamics. It was seen as an academic yardstick before the advent of grille shutter systems. However, their introduction has increased the need to accurately predict the drag of a vehicle in a variety of different cooling configurations during vehicle development. This currently represents one of the greatest predictive challenges to the automotive industry due to being the net effect of many flow field changes around the vehicle. A comprehensive study is presented in the paper to discuss the notion of defining cooling drag as a number and to explore its effect on three automotive models with different cooling drag deltas using the commercial CFD solvers; STARCCM+ and Exa PowerFLOW.
Technical Paper

Sand Dune Impact Simulation

2017-03-28
2017-01-1318
Robustness to sand dune impact is one of the key requirements for Jaguar Land Rover products. Historically off road vehicles were built on a ladder sub frame; and the steel cross beam at the front provided robust protection for the cooling pack. With the move to monocoque construction, the cooling pack became vulnerable to low speed grounding damage. Unfortunately this vulnerability is not confirmed until later in the program when fully representative vehicles are available, which results in late engineering changes that are expensive, time consuming and stressful. Like all late changes it is rarely optimised for cost and weight. With no historic literature or procedure available, the challenge was to model the physics of sand media and also solve the complex multi-physics problem of impact of the whole vehicle with the sand dune.
Technical Paper

Prediction of Vehicle Interior Sound Pressure Distribution with SEA

2011-05-17
2011-01-1705
Statistical Energy Analysis (SEA) is the standard analytical tool for predicting vehicle acoustic and vibration responses at high frequencies. SEA is commonly used to obtain the interior Sound Pressure Level (SPL) due to each individual noise or vibration source and to determine the contribution to the interior noise through each dominant transfer path. This supports cascading vehicle noise and vibration targets and early evaluation of the vehicle design to effectively meet NVH targets with optimized cost and weight. A common misconception is that SEA is only capable of predicting a general average interior SPL for the entire vehicle cabin and that the differences between different locations such as driver's ear, rear passenger's ear, lower interior points, etc., in the vehicle cannot be analytically determined by an SEA model.
Technical Paper

SEA Wind Noise Load Case for Ranking Vehicle Form Changes

2011-05-17
2011-01-1707
Vehicle manufacturers demand early design assessment of vehicle wind noise attribute so as to eliminate engineering waste induced by late design changes. Vehicle wind noise attribute can be simulated with a Statistical Energy Analysis (SEA) model using exterior surface turbulence pressure on the vehicle greenhouse panel as the wind noise load. One important application of SEA wind noise model is the wind noise assessment for vehicle form design. Vehicle form optimization for wind noise plays an important role in lightweight vehicle architecture, since that reduction in the wind noise load will compensate the loss of vehicle body acoustic attenuation caused by down-gauge glazing and body panels. In this paper, two SEA wind noise load cases currently used in vehicle SEA wind noise modeling have been analyzed and evaluated against vehicle measurements.
Technical Paper

Measurement of Exterior Surface Pressures and Interior Cabin Noise in Response to Vehicle Form Changes

2011-05-17
2011-01-1618
Automotive manufactures demand early assessment of vehicle form design against wind noise attribute to eliminate any engineering waste induced by late design changes. To achieve such an assessment, it is necessary to determine a measurable quantity which is able to represent vehicle form changes, and to understand the relationship between the quantity and vehicle interior cabin noise. This paper reports experimental measurements of vehicle exterior surface pressure and the interior cabin noise level in response to the change of exterior rear view mirror shape. Measurements show that exterior surface pressure on vehicle greenhouse panel is a primary factor of wind noise load to the interior cabin noise; they can be used in preliminary wind noise ranking. Care should be taken when using them in ranking vehicle form wind noise performance. It has been observed that a change in surface pressure on the front side window does not necessarily lead to a change in the interior cabin noise.
Technical Paper

Effect of Setting Velocity on Self-Piercing Riveting Process and Joint Behaviour for Automotive Applications

2010-04-12
2010-01-0966
The increased application of lightweight materials, such as aluminium has initiated many investigations into new joining techniques for aluminium alloys. As a result, Self-piercing riveting (SPR) was introduced into the automotive industry as the major production process to join aluminium sheet body structures. Although both hydraulic and servo types of SPR equipment are used by the industry, the servo type is most commonly used in a volume production environment. This type uses stored rotational inertia to set the rivet. The initial rotational velocity of the mass dictates the setting force and hence the tool is described as velocity-controlled. A study was therefore conducted to examine the effect of setting velocity on the process including tooling and joint performance. It was found that the setting velocity would have a significant effect on tooling life. Over 80kN force could be introduced into the tooling depending on selection of the setting velocity.
Technical Paper

Model-Based Assurance for Justifying Automotive Functional Safety

2010-04-12
2010-01-0209
With the growing complexity of, and reliance on, safety-related electrical/electronic (E/E) systems in the automotive sector, the development of an explicit safety case is highly recommended to provide assurance to the different stakeholders interested in automotive functional safety. The production of a safety case is explicitly mandated by the draft automotive functional safety standard ISO26262. A safety case should consider all organisational and technical factors that may contribute to safety. For example, it should provide assurance for the safe behaviours of a particular system as well as assurance for the process by which this system is developed, operated and maintained. In this paper, we address one component of the overall safety case, namely the assurance of the functional safety concept. In particular, we examine how model-driven development and assessment can provide a basis for the systematic generation of functional safety requirements.
Technical Paper

The Effects of Unsteady On-Road Flow Conditions on Cabin Noise

2010-04-12
2010-01-0289
At higher speeds aerodynamic noise tends to dominate the overall noise inside the passenger compartment. Large-scale turbulent conditions experienced on the road can generate different noise characteristics from those under steady-state conditions experienced in an acoustic wind tunnel. The objective of this research is to assess the relationship between on-road flow conditions and the sound pressure level in the cabin. This research, covering links between the unsteady airflow around the vehicle and aeroacoustic effects, is a natural progression from previous aerodynamic studies. On-road testing was undertaken using a current production vehicle equipped with a mobile data logging system. Testing was carried out on major roads at typical highway speeds, where wind noise is very significant. Of particular interest are high-yaw conditions, which can lead to a blustering phenomenon.
Technical Paper

The Effect of Base Bleed and Rear Cavities on the Drag of an SUV

2010-04-12
2010-01-0512
Two methods of passive flow control were investigated to determine their effectiveness in reducing aerodynamic drag on large Sports Utility Vehicles (SUVs). Passive means of flow control were selected since all active methods require the input of additional energy (e.g., pressurized fluids or electrical energy). The selected methods were base bleed and the use of a rear cavity, and various combinations of these were experimentally tested in full-scale wind tunnels with and without a moving belt/rotating wheel assembly. Aerodynamic drag reduction was accomplished by restructuring the low-pressure wake directly behind the vehicle. External cavity depths ranging from d/h=0.17 to 0.83 were used, while body cavity depths ranged from d/h=0 to 0.83, where the depth of the cavity d is non-dimensionalized by the height h of the base area.
Technical Paper

Engine Test Data Quality Requirements for Model Based Calibration: A Testing and Development Efficiency Opportunity

2013-04-08
2013-01-0351
This paper documents some of the findings from a joint JLR and AVL project which was conducted at the JLR Gaydon test facility in the UK. A testing and development efficiency concept is presented and test data quality is identified as a key factor. In support of this methods are proposed to correctly measure and set targets for data quality with high confidence. An illustrative example is presented involving a Diesel passenger car calibration process which requires response surface models (RSMs) of key engine measured quantities e.g. engine-out emissions and fuel consumption. Methods are proposed that attempt to quantify the relationships between RSM statistical model quality metrics, test data variability measures and design of experiment (DOE) formulation. The methods are tested using simulated and real test data.
Technical Paper

Robustness Modelling of Complex Systems - Application to the Initialisation of a Hybrid Electric Vehicle Propulsion System

2013-04-08
2013-01-1231
Robustness is particularly important in complex systems of systems due to emergent behaviour. This paper presents two novel, techniques developed as part of a framework for design for robustness of complex automotive electronic systems, but in principle could be applied to a broad range of distributed electronic systems. The overall framework is described to give the context of use for the techniques. The first technique is a “robustness case” which is a structured argument for the robustness of a system analogous to a safety case. The second is a model based approach to early robustness verification of complex systems. The approaches are demonstrated by their application to the system initialisation of the propulsion control system of a hybrid electric vehicle. The hybrid system initialisation process is discussed in terms of the key objectives and the technical implementation, illustrating the level of complexity underlying a simple high level requirement.
Technical Paper

Exploring the Value of Open Source in SI Engine Control

2011-04-12
2011-01-0702
The notion of open source systems has been well established in systems software and typified by the development of the Linux operating system. An open source community is a community of interest that makes use of software tools in research and development. Their ongoing development is part of the free flow of ideas on which the community. The motivation for the work reported in this paper is to provide the research community in engine controls with a ready access to a complete engine management solution and the component parts. The work described in this paper extends open source principles to engine control with a portable spark ignition (SI) control strategy assembled using Simulink. The underlying low level drivers are written in C and designed for portability. A calibration tool is written in C and works over a controller area network (CAN) link to the engine control unit (ECU). The ECU hardware is based on the Infineon Tricore microcontroller.
Technical Paper

Design and Comparative Study of Yaw Rate Control Systems with Various Actuators

2011-04-12
2011-01-0952
The vehicle dynamics control systems are traditionally based upon utilizing wheel brakes as actuators. However, there has been recently strong interest in the automotive industry for introduction of other vehicle dynamics actuators, in order to improve the overall vehicle stability, responsiveness, and agility features. This paper considers various actuators such as active rear and central differentials and active front and rear steering, and proposes design of related yaw rate control systems. Different control subsystems such as reference model, feedback and feedforward control, allocation algorithm, and time-varying controller limit are discussed. The designed control systems are verified and compared by computer simulation for double lane change and slalom maneuvers.
Technical Paper

Recent Advances in Powertrain Sound Quality Hardware Tuning Devices and Perspectives on Future Advances

2009-05-19
2009-01-2192
Over the past decade there have been significant advances made in the technology used to engineer Powertrain Sound Quality into automobiles. These have included exhaust system technologies incorporating active and semi-active valves, intake system technologies involving passive and direct feedback devices, and technologies aimed at tuning the structure-borne content of vehicle interior sound. All of these technologies have been deployed to complement the traditional control of NVH issues through the enhancement of Powertrain Sound Quality. The aim of this paper is to provide an historical review of the recent industry-wide advances made in these technologies and to provide the author's perspective on what issues have been addressed and what opportunities have been delivered.
Technical Paper

Model Based Design of Robust Vehicle Power Networks

2008-04-14
2008-01-0898
Electrical power requirements for vehicles continue to increase. Future vehicle applications require the development of reliable and robust power supply strategies that operate over various ambient temperatures and driving conditions. Insufficient charge balance is one of the major concerns for conventional lead-acid battery systems when operated with limited charging times during short journeys or extreme climate conditions. For vehicle power supply analysis, a detailed understanding of the operational characteristics of the major components and how they interact as a part of the electric power system, including environmental and road conditions, is essential if the analysis is to aid system optimization. This paper presents a model based technique that enhances the process of vehicle electrical power system design. Vehicle system optimization using virtual prototypes has become critically important as more electrical features are added to future vehicles.
Technical Paper

An Optical Study of DMF and Ethanol Combustion Under Dual-Injection Strategy

2012-04-16
2012-01-1237
The new fuel, 2, 5-dimenthylfuran, known as DMF, captured worldwide attention since the discovery of its new production method. As a potential bio-fuel, DMF is competitive to gasoline in many areas, such as energy density, combustion efficiency and emissions. However, little work has been performed on its unconventional combustion mode. In this work, high speed imaging and thermal investigation are carried out to study DMF and gasoline dual-injection on a single cylinder, direct injection spark ignition optical engine. This dual-injection strategy combines direct injection (DI) and port fuel injection (PFI) simultaneously which means two different fuels can blend in the cylinder with any ratio. It provides a flexible way to use bio-fuels with gasoline. DMF DI with gasoline PFI and ethanol DI with gasoline PFI are studied under different injection proportions (by volume) and IMEPs.
Technical Paper

In-Cylinder Optical Study on Combustion of DMF and DMF Fuel Blends

2012-04-16
2012-01-1235
The bio-fuel, 2,5 - dimethylfuran (DMF) is currently regarded as a potential alternative fuel to gasoline due to the development of new production technology. However, little is known about the flame behavior in an optical engine. In this paper, high speed imaging (with intensifier) was used during the combustion of DMF and its blends with gasoline and ethanol (D50, D85, E50D50 and E85D15) in an SI optical engine. The flame images from the combustion of each fuel were analyzed at two engine loads: 3bar and 4bar IMEP. For DMF, D50 and E50D50, two modes were compared: DI and PFI. The average flame shapes (in 2D) and the average flame speeds were calculated and combined with mass fraction burned (MFB) data. The results show that when using DMF, the rate of flame growth development and flame speed is higher than when using gasoline. The differences in flame speed between DMF and gasoline is about 10% to 14% at low IMEP.
Technical Paper

Accurate Model Based Hardware-in-the-Loop Test for a Windscreen Wiper System

2012-04-16
2012-01-1164
Hardware-in-the-loop (HIL) simulations have long been used to test electronic control units (ECUs) and software in car manufacturers. It provides an effective platform to the rapid development process of the ECU control algorithms and accommodates the added complexity of the plant under control. Accurate Model based HIL simulation (AMHIL) is considered as a most efficient and cost effective way for exploration of new designs and development of new products, particularly in calibration and parameterization of vehicle stability controllers. The work presented in the paper is to develop a mathematical model of a windscreen wiper system for the purpose of conducting HIL vehicle test and eventually to replace the real component with the model for cost cutting and improved test efficiency. The model is developed based on the electro-mechanical engineering principles.
Technical Paper

An Initial Study to Develop Appropriate Warning Sound for a Luxury Vehicle Using an Exterior Sound Simulator

2011-05-17
2011-01-1727
Many electric (EV) and hybrid-electric (HEV) vehicles are designed to operate using only electric propulsion at low road speeds. This has resulted in significantly reduced vehicle noise levels in urban situations. Although this may be viewed by many as a benefit, a risk to safety exists for those who rely on the engine noise to help detect the presence, location and behaviour of a vehicle in their vicinity. In recognition of this, legislation is being introduced globally which will require automotive manufacturers to implement external warning sound systems. A key challenge for premium vehicle manufacturers is the development of a suitable warning sound signature which also conveys the appropriate brand aspirations for the product. A further major difficulty exists when trying to robustly evaluate potential exterior sounds by running large-scale trials in the real world.
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