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Technical Paper

Rapid Aerodynamic Development of Two-Volume Vehicle Shapes

2000-03-06
2000-01-0488
The objective behind this effort is rapid aerodynamic development of vehicle themes, in the early stages of vehicle development. This paper describes a process that is suitable for the development of two-volume (or two-box) vehicle shapes (such as station wagons, minivans or sports utility vehicles). Traditionally, aerodynamic development at this stage is accomplished using wind-tunnel tests of full or partial scale test models or relying on simulations of aerodynamics employing computational fluid dyanmics (CFD). In either case, the process is not particularly effective in sustaining the desired level of communication between designers (engaged in styling activities) and engineers (engaged in packaging and aerodynamics). A key drawback here is the delay in the generation of aerodynamic drag estimates for the proposals under consideration through use of wind-tunnel tests or CFD computations.
Technical Paper

Conversion of a Multivalve Gasoline Engine to Run on CNG

2000-03-06
2000-01-0673
A production SI engine originally designed at Fiat Auto to operate with unleaded gasoline was converted to run on natural gas. To that end, in addition to designing and building the CNG fuel plant, it was necessary to replace the multipoint electronic module for injection-duration and ignition-timing control with an ECM designed to obtain multipoint sequential injection. The engine was modified so as to work either with gasoline or natural gas. For the present investigation, however, the engine configuration was not optimized for running on methane, in order to compare the performance of the engine operated by the two different fuels with the same compression ratio. In fact, the engine is also interesting as a dual-fuel engine because of its relatively high compression ratio ≈10.5 that is almost suitable for CNG operation. The engine had the main features of being a multivalve, fast-burn pent-roof chamber engine with a variable intake-system geometry.
Technical Paper

A Side-Slip Angle Estimation Using Neural Network for a Wheeled Vehicle

2000-03-06
2000-01-0694
Decreasing a stabilizing yaw moment by a large side-slip angle of a vehicle causes an unstable motion in a nonlinear region. Recently, in order to stabilize the vehicle motion in the region, Direct Yaw Moment Control (DYC) by using differences of driving and braking forces on right and left wheels has been developed and focused. Especially, performances of the handling and the stability are improved by DYC became DYC the side-slip angle together with a yaw rate control. For such DYC, the side-slip angle is crucial information. However, it has been difficult to utilize a control system by using DYC with the side-slip angle, because a special devise for the measurement is necessary. Moreover, time-integration is not suitable for sensor data such as the lateral acceleration, the vehicle velocity, and the yaw rate because of an accumulation of noise and measurement errors.
Technical Paper

Fuel Economy Improvements through Improved Automatic Transmission Warmup - Stand Alone Oil to Air (OTA) Transmission Cooling Strategy with Thermostatic Cold Flow Bypass Valve

2001-05-14
2001-01-1760
The stand alone oil to air (OTA) transmission cooling strategy with thermostatic cold flow bypass valve has been shown to be an effective means of improving the warmup of an automatic transmission. Improving the system warmup rate of an automatic transmission significantly improves its efficiency by reducing losses resulting from extremely viscous transmission fluid and can allow for calibration changes that improve overall transmission performance. Improved transmission efficiency in turn allows for improved engine efficiency and performance. The improvements obtained from increased transmission and engine efficiency result in an overall increase in vehicle fuel economy. Fuel economy and consumption are important parameters considered by the vehicle manufacturer and the customer. Fuel economy can be considered as important as reliability and durability.
Technical Paper

AIR COOLING SYSTEM FOR SMALL INTERNAL COMBUSTION ENGINE EXPERIMENTAL ANALYSIS.

2001-12-01
2001-01-1790
0 In this work we illustrate a data acquisition system realization and set up for the experimental description of an air cooling system for a four stroke, one - cylinder engine used on scooters. The high importance of the power absorbed by cooling system at medium and high rotational speeds is the first reason of this investigation, our target is to point out possible increasing in the forced ventilation cooling system performances. First of all, in order to foresee the magnitude order of the measured variables, we developed a theoretical one-dimensional description of the centrifugal blower, with this approach we can forecast, even if in an approximated way, the measured variables magnitude order. Obviously, in order to realize the blower and flow experimental characterization, it was necessary the choice of the right test rig.
Technical Paper

Development of PEMS Models for Predicting NOx Emissions from Large Bore Natural Gas Engines

2001-05-07
2001-01-1913
In this work two different Parametric Emissions Monitoring System (PEMS) models are developed, an algebraic, semi-empirical model and a neural network model. The semi-empirical model is based on general relationships between oxides of nitrogen (NOx) emissions and engine parameters. The neural network model utilizes a similar set of input parameters, but relies on the neural network code to determine the relationships between input parameters and measured NOx emissions. Two sets of data are used for model development. The first set is composed of typical engine parametric variations and is used to train the models. The second set is used to test the models and is composed of changes to engine operation associated with engine degradation, termed Operations and Maintenance (O&M) issues.
Technical Paper

Some Statistical, Technical, and Practical Issues in Virtual Engine Testing

2001-05-07
2001-01-1906
API's Engine Oil Licensing and Certification System has implemented Provisional Licensing in response to a shortage of parts for the Sequence IIIE engine test. A Task Force delegated by the ASTM Sequence II/III Surveillance Panel was asked to develop a process, if appropriate, for the use of mathematical models as a substitute for the Sequence IIIE engine test. The Task Force tried to develop a fair and technically justifiable system for predicting engine oil performance based on models derived from existing engine test databases. The situation appeared to some to be the ideal application for initiating and proving a virtual test approach. In the end, others said the situation was too time-constrained or limited in scope. This paper describes some of the statistical, technical, and practical issues involved in specifying a process for virtual testing. Some perspectives on these issues as discussed in the Task Force effort are explored.
Technical Paper

Model Based Determination of Dynamic Engine Control Function Parameters

2001-05-07
2001-01-1981
The use of model based approaches in areas such as simulation, control design, optimization, etc. is crucial for the development of highly sophisticated systems. This is especially true for typically very tight time-to-market frames. Physical modeling of IC engine emissions based on first principles is extremely complex and still requires by far too much calculation time. However, special fast neural networks represent a promising alternative for an accurate modeling of the emission behavior, even for dynamic conditions. This paper first describes the process of developing dynamic neural emission models. The required data is collected by a specially designed dynamic measurement strategy. The models themselves are then used for the optimization of the dynamic engine behavior concerning consumption, emissions and drivability.
Technical Paper

Development of an Artificial Neural Network Based Fault Diagnostic System of an Electric Car

2000-03-06
2000-01-1055
The objective of this work is to develop a fault diagnostic system of an electric car based on artificial neural networks (ANN). Data from an on-board data acquisition system capable of measuring a number of parameters during the electric car operation are used to train an artificial neural network. The car's monitoring system using the computational power of modern portable personal computers, user-friendly data input and output, and full-screen editor capabilities is used for fault diagnosis. The ANN was trained to predict the temperature of the two motors of the electric car in order to detect any fault. The training data were learned by the ANN with an excellent accuracy. The results obtained for the training set are such that they yield coefficients of multiple determination (R2-values) equal to 0.9912 and 0.9939 corresponding to the values of the temperatures of the two motors respectively. Completely unknown data were then used for validation of the network.
Technical Paper

On Line Working Neural Estimator of SI Engines Operational Parameters

2000-03-06
2000-01-1247
In this paper the evaluation of the suitability of the Artificial Neural Networks for setting up simulation modules for “analytical redundancy” was further carried out. The performance of the ANN modules was enhanced, by taking into account the engine dynamics for the simulation of fast engine transients and obtaining satisfactory results. Working toward actual on board application in Fault Diagnosis systems, some ANN modules were implemented in an on-line system which acquires signals from an engine mounted on a test bench and compares in real time the experimental values with the estimated ones. In this way, it was possible to perform long duration tests of ANN's behaviour, substantially confirming the results of the conventional off-line analysis.
Technical Paper

Hybrid Air/Fuel Ratio Control Using the Adaptive Estimation and Neural Network

2000-03-06
2000-01-1251
The paper describes a hybrid air-fuel mixture control system that uses neural network and the direct adaptive algorithm. The A/F ratio stabilization to the stoichiometric value is required to obtain maximum efficiency of the three-way catalytic converter operation. The issues of the algorithm synthesis of the adaptive control of the fuel injection have been formulated. This was supplemented by the presentation of the state-of-the-art in the adaptive control theory as applied to non-stationary random object identification. The control algorithms of the fuel injection have been reviewed and classified. The fuel injection algorithms in the SI engine have been described and differentiated in terms of the used engine model and regulator structure. The algorithms comprise elements of the object modeling as well as adaptive coefficients for the control quality of the air-fuel ratio in the steady and non-steady conditions.
Technical Paper

Estimating the Air/Fuel Ratio from Gaussian Parameterizations of the Ionization Currents in Internal Combustion SI Engines

2000-03-06
2000-01-1245
In this paper we use the idea of parameterizing the ionization current using the sum of two Gaussian functions in an indirect scheme to estimate the AFR. In the first step of the scheme, the Gaussian functions are fitted to the ion signal using a standard least-squares fit. Then, as a second step, the AFR is estimated using the six parameters of the Gaussian functions plus the ignition angle and measurements of the engine speed. The experimental tests show that it is possible to estimate the AFR with good accuracy, using this approach. The best results were obtained using a neural network approach and it is shown in the paper that the AFR can be estimated from the ionization current down to approximately 0.1% in mean square error.
Technical Paper

Calibrating Powertrain Control Systems with 32-bit ECUs

2000-03-06
2000-01-1244
For more than a decade, automotive engineers have refined their techniques for developing control systems in automotive powertrain applications. One critical element of the product development process is real-time calibration of the control variables. Calibration of automotive powertrain control systems depends heavily on non-intrusive memory access for transparent data acquisition and calibration exercises during engine operation on the dynamometer and in-vehicle driveability testing. This paper provides a brief background and description of the challenges that will be encountered on ECU design projects incorporating 32-bit microprocessors. The most promising solutions to this problem are presented and the tradeoffs associated with their implementation are discussed.
Technical Paper

Approach of Debugging Control Laws of ABS Combined with Hardware-in-the-Loop Simulation and Road Experiment

2001-11-12
2001-01-2729
Anti-lock Braking System (ABS) is an important control system that can improve the automotive performance, reliability and safety obviously. Hardware-in-the-loop Simulation (HILS) testing is a promising method to assistant design automotive electronics system. In the State Key Laboratory of Automotive Safety and Energy, a HILS system was established to assistant design ABS. The HILS system is composed of a hydraulic control unit of ABS, a normal brake system, a commercial personal computer, a data acquisition card, and several signal-conditioning modules. Powerful software was programmed to perform managing input and output signals, solving 7-freedom and 15-freedom vehicle models, and acquiring response signals of the brake system. Based on the simulations of HILS system, the road experiments with the same conditions of ABS are very necessary and important.
Technical Paper

Utilization of Artificial Neural Networks in the Control, Identification and Condition Monitoring of Hydraulic Systems - An Overview

2000-09-11
2000-01-2591
There has been considerable interest and activity in the area of application of the artificial neural network (ANN) to hydraulic systems. The pattern recognition capabilities of the ANN has led to an early investigation in areas where the neural networks could be trained using signals that were at least statistically similar to those signals which the trained ANN would be exposed during operation. The dynamic and encompassing nature of hydraulic system signals poses more of a challenge to ANN training and implementation than one of only pattern recognition. However, in the past decade, there has been considerable activity and progress in the application of ANN techniques for hydraulic systems control, identification and condition monitoring. This paper provides an overview of work in this area. The ANN has proven to be a valuable addition to the current existing techniques.
Technical Paper

Different Strategies for Transient Control of the Air-Fuel Ratio in a SI Engine

2000-10-16
2000-01-2835
This paper compares several strategies for air-fuel ratio transient control. The strategies are: A factory standard look-up table based system (a SAAB Trionic 5), a feedback PI controller with and without feed-forward throttle correction, a linear feed-forward control algorithm, and two nonlinear feed-forward algorithms based on artificial neural networks. The control strategies have been implemented and evaluated in a SAAB 9000 car during a transient driving test, consisting of an acceleration in the second gear from an engine speed of 1500 rpm to 3000 rpm. The best strategies are found to be the neural network based ones, followed by the table based factory system. The two feedback PI controllers offer the poorest performance.
Technical Paper

Pass-By Noise Prediction for Trucks Based on Powertrain Test-Cell Measurements

2001-04-30
2001-01-1563
The paper outlines and discusses the possibilities of a new instrumentation tool for the analysis of engine and gearbox noise radiation and the prediction of pass-by noise from powertrain test cell measurements. Based on a 32 channel data acquisition board, the system is intended to be quick and easy to apply in order to support engineers during their daily work in the test cell. The pass-by prediction is a purely experimental approach with test cell recordings being weighted by measured transfer functions (from the powertrain compartment to the pass-by point).
Technical Paper

Data Acquisition and Power Control System for Thermal Test on Spacecraft at 4m Thermal Vacuum Chamber

2001-07-09
2001-01-2245
A computer based data acquisition and power control system has been designed and installed for conducting thermal test at 4M thermal vacuum chamber of ISRO Satellite Centre(ISAC), Bangalore, INDIA. The system consists of four main units viz. Temperature Signal Processing Unit(TSPU), Power and Control Unit(PACU), Spacecraft telemetry and thermal vacuum chamber facility data interface unit and Data Processing Unit(DPU). The system has capability of monitoring 512 thermocouple channels, 700 spacecraft telemetry thermal related parameters, facility parameters including chamber Vacuum level, chamber contamination level using Quartz Crystal Monitor data and 128 numbers of heat-flux/temperature control channels. TSPU and PACU are VME based system. DPU is based on Pentium processor with hot redundancy using Redundant Array Of Inexpensive Disks(RAID) to takeover in case of failure of a server. All the subsystem and their peripherals are networked using TCP/IP on Ethernet.
Technical Paper

A Microprocessor Based Soil Moisture Sensor System for Space Based Plant Growth Units

2001-07-09
2001-01-2181
A soil moisture sensor system consisting of small heat-pulse probes, a microcontroller, and software for data acquisition and signal conditioning was developed for use in space based plant growth units. The microcontroller allows the sensors to be used in a control application with minimum time demands on the control subsystem. A single digital serial link may be shared by up to 16 microcontrollers with 8 sensors each, for a total of 128 sensors. The microcontroller independently applies heat cycles to determine the current moisture level, and responds to a request from the computer with the last known value. Using the microcontroller system, repeatability testing was completed for wet 1–2 mm arcillite. The standard deviation in wet arcillite over a 16-hour period was about 3%. Software filtering can be used to reduce the standard deviation further.
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