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Technical Paper

The Auto-Generation of Calibration Guides from MATLAB® Simulink®

With the inception of model-based design and automatic code generation, many organizations are developing controls and diagnostics algorithms in model-based development tools to meet customer and regulatory requirements. Advances in model-based design have made it easier to generate C code from models and help software engineers streamline their workflow. Typically, after the software has been developed, the models are handed over to a calibration team responsible for calibrating the features to meet specified customer and regulatory requirements. However, once the models are handed over to the calibration team, the calibration engineers are unaware of how to calibrate the features because documentation is not available. Typically, model documentation trails behind the software process because it is created manually, most of this time is spent on formatting. As a result, lack of model documentation or up-to date documentation causes a lot of pain for OEM’s and Tier 1 suppliers.
Technical Paper

Closed Loop Pressure Control System Requirements and Implementation

Electro-hydraulic actuation has been used widely in automatic transmission designs. With greater demand for premium shift quality of automatic transmissions, higher pressure control accuracy of the transmission electro-hydraulic control system has become one of the main factors for meeting this growing demand. This demand has been the driving force for the development of closed loop pressure controls technology. This paper presents the further research done based upon a previously developed closed loop system. The focus for this research is on the system requirements, such as solenoid driver selection and system latency handling. Both spin-stand and test vehicle setups are discussed in detail. Test results for various configurations are given.
Technical Paper

Improving Time-To-Collision Estimation by IMM Based Kalman Filter

In a CAS system, the distance and relative velocity between front and host vehicles are estimated to calculate time-to-collision (TTC). The distance estimates by different methods will certainly include noise which should be removed to ensure the accuracy of TTC calculations. Kalman filter is a good tool to filter such type of noise. Nevertheless, Kalman filter is a model based filter, which means a correct model is important to get the good filtering results. Usually, a vehicle is either moving with a constant velocity (CV) or constant acceleration (CA) maneuvers. This means the distance data between front and host vehicles can be described by either constant velocity or constant acceleration model. In this paper, first, CV and CA models are used to design two Kalman filters and an interacting multiple model (IMM) is used to dynamically combine the outputs from two filters.
Journal Article

Energy-Efficient Air Conditioning Systems Utilizing Pneumatic Variable Compressors

Air Conditioning systems with reheat reduction based for energy efficiency have generally been implemented with either electronic variable compressors through active stroke control or with fixed displacement compressors through modifying the cycling set point. The present work demonstrates a unique concept of achieving energy efficiency via cycling a pneumatic variable compressor at elevated set points. The energy efficiency of such a system approaches that of an electronic variable but significantly higher than that of a fixed displacement compressor system. The cost of the system, on the other hand, is substantially lower than that of an electronic compressor. Secondary benefits include a softer start than with a fixed compressor and a considerably simpler control scheme than that required by an electronic variable compressor.
Journal Article

Fuel Efficiency Improvements from Lean, Stratified Combustion with a Solenoid Injector

In light of the growing emphasis on CO2 emissions reduction, Delphi has undertaken an internal development program to show the fuel economy benefits of lean, stratified combustion with its outwardly-opening solenoid injector in a vehicle environment. This paper presents the status of this ongoing development activity which is not yet completed. Progress to date includes a logical progression from single- and multi-cylinder dynamometer engines to the vehicle environment. The solenoid-actuated injector used in this development has an outwardly-opening valve group to generate a hollow-cone spray with a stable, well-defined recirculation zone to support spray-guided stratification in the combustion chamber. The engine management system of the development vehicle was modified from series-production configuration by changing the engine control unit to permit function development and calibration.
Journal Article

Diagnostics based on the Statistical Correlation of Sensors

The paper describes a new strategy for real-time sensor diagnostics that is based on the statistical correlation of various sensor signal pairs. During normal fault-free operation there is a certain correlation between the sensor signals which is lost in the event of a fault. The proposed algorithm quantifies the correlation between sensor signal pairs using real-time scalar metrics based on the Mahalanobis-distance concept. During normal operation all metrics follow a similar pattern, however in the event of a fault; metrics involving the faulty sensor would increase in proportion to the magnitude of the fault. Thus, by monitoring this pattern and using a suitable fault-signature table it is possible to isolate the faulty sensor in real-time. Preliminary simulation results suggest that the strategy can mitigate the false-alarms experienced by most model-based diagnostic algorithms due to an intrinsic ability to distinguish nonlinear vehicle behavior from actual sensor faults.
Technical Paper

A Statistical Approach for Real-Time Prognosis of Safety-Critical Vehicle Systems

The paper describes the development of a vehicle stability indicator based on the correlation between various current vehicle chassis sensors such as hand wheel angle, yaw rate and lateral acceleration. In general, there is a correlation between various pairs of sensor signals when the vehicle operation is linear and stable and a lack of correlation when the vehicle is becoming unstable or operating in a nonlinear region. The paper outlines one potential embodiment of the technology that makes use of the Mahalanobis distance metric to assess the degree of correlation among the sensor signals. With this approach a single scalar metric provides an accurate indication of vehicle stability.
Technical Paper

Overview of Remote Diagnosis and Maintenance for Automotive Systems

Advances in wireless communications, model-based diagnostics, human-machine interfaces, electronics and embedded system technologies have created the foundation for a dramatic shift in the way the vehicles are diagnosed and maintained. These advances will enable vehicle diagnosis and maintenance to be performed remotely while the vehicle is being driven. There also has been recent strong consumer interest in Remote Diagnosis and Maintenance (RD&M). As a consequence, RD&M is drawing increased attention in the automotive industry. This paper provides the current status of vehicle remote diagnosis and maintenance, analyses the potential features of RD&M and their significance, and discusses how next generation automotive products could benefit from research and development in this area.
Technical Paper

Diagnosis Concept for Future Vehicle Electronic Systems

As automotive electronic control systems continue to increase in usage and complexity, the challenges for developing automotive diagnostics also increase. Reduced development cycle times, the increased significance of diagnostics for safety critical systems, and the integration of vehicle systems across multiple control systems all add to the tasks of developing diagnostics for the automobiles of today and tomorrow. Addressing automotive diagnostics now requires the Tier 1 supplier to utilize a formal diagnostic development methodology. There are also opportunities for Tier 1 suppliers to add value by developing vehicle-level supervisory diagnostic strategies, in addition to subsystem and system-level diagnostic strategies. There is also a prospect to provide strategies and tools to enhance service at the vehicle level. This paper proposes an approach for Tier 1 suppliers to address diagnostic and service issues at the component, system, and vehicle level.
Technical Paper

Toward an Objective Understanding of Perceived Glovebox Closure Sound Quality

As an essential dimension of product harmony and craftsmanship, product sound quality has drawn increasing attention from customers in recent years. To meet this customer requirement, Delphi Corporation has been taking a proactive role in understating customer preferences, improving designs, and developing a sound quality knowledge base for this purpose. This study investigates the characteristics of the glovebox closure sound that affects the customer's perception of the product harmony and craftsmanship. Previous research has indicated that the perceived closure sound quality is affected by the spectral balance, the occurrence of multiple impulses, and the duration of the closing event. The primary goal of this study is to explore how these parameters affect the perception of glovebox sounds and to what extent. A jury evaluation was conducted with a sequence of glovebox closure sounds, which were derived from an existing recording.