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Technical Paper

Road Tests of a Misfire Detection System

This paper presents the theory and experimental performance of a system for detecting engine misfires in automobiles. The method is potentially suitable for meeting the California Air Resources Board (CARB) requirements under On Board Diagnostics II (OBDII) rules. The instrumentation for the present method measures (noncontacting) crankshaft instantaneous angular speed. Highly efficient signal processing algorithms permit detection of each individual misfire. The performance of the present method is expressed in terms of error rates made in detecting individual misfires. Normal operating conditions yield error rates under 10-4. Under worst case conditions consisting of light load, high RPM and rough roads with the torque converter in lockup are under 10-3.
Technical Paper

An Effective Logical Wire Connection Verification Algorithm for Automotive Wiring System

As the number of user selectable electrical modules increases for passenger car, the number of cars with different combinations of option can easily exceed 100,000 cars. It results to a situation where we can not manually verify all the logical connection by making wiring combinations for each car. In this paper, we propose an algorithm that can reduce verification time for all possible wiring with available option combinations. The algorithm separates the whole wiring circuits into independent circuits and verifies the logical connections for each independent circuit with all possible options. The algorithm is time effective so the required time to verify the connections increases logarithmically as the number of possible car increases. The algorithm was implemented as software verification tool and its effectiveness was proved to be feasible.
Technical Paper

A Screening Attenuation Evaluation Method for HEV Power Cable

This paper proposes a new screening attenuation evaluation method (PHSA) for hybrid power cables. Hybrid power cables connect battery, inverter and motor. As the noise and shield characteristics of these cables are different from general communication shield wires, new method for evaluating screening attenuation is needed. We considered the radiation direction, noise current path and various load terminations to evaluate the screening attenuation which is different from standard screening attenuation measurement. Feasibility and effectiveness of the proposed method were verified with real experiment results.
Technical Paper

User Interface Based Shield Effectiveness Analysis Modeling Tool for Hybrid Electric Vehicle Three Phase Power Harness

In automotive industry, to deal with EMI problems, an efficient and proper screening attenuation measurement method is needed to make high performance and low cost shielded electrical wiring harness. Previously a screening attenuation measurement method titled PHSA (Power Harness screening attenuation) method [ 1 ] was proposed to measure screening attenuation in shielded power cable, which evaluates the shielding performance that prevents radiation from inner core to outside environment. The method was used to practically check the effects on performance of cable shield (shield effectiveness) due to different combinations of length and braid density against radiated noise. But the measurement time for actually performing experimental tests limits measurable combinations to evaluate the shielding performance of the wiring harness.
Technical Paper

Development of Module Based IPS Evaluation System

A module based IPS (Intelligent Power Switch) evaluation system is proposed in this paper. As the IPS is gradually replacing the conventional relay and fuses, the stability and reliability of power system depends more on these IPS. The proposed IPS evaluation system outperforms the conventional manual evaluation in terms of speed and efficiency. This paper will introduce the structure of hardware and software of the IPS evaluation system. The system is placed between the module and cable connector to evaluate the module in an operating car without changing the cables. The control and signal processing is carried out by personal computer which is connected to the evaluation system by USB (Universal Serial Bus). The load resistance can be switch from actual load to arbitrary value using relay circuitry and DC electric load controlled by GPIB (General Purpose Interface Bus). CAN (Controller Area Network) circuits were added to control the IPS mounted inside the module.
Technical Paper

Systematic Automotive Wiring Guideline Based on Coupling Theory

This paper introduces a systematic wiring guideline which includes coupling noise calculation, wire layout design, and wire type selection methodologies. The coupling theory between wires has been introduced long time ago but it was not successfully applied to real automotive wiring design due to the complexity in the theory such as large number of parameters and many different conditions in automotive wiring environment. In this paper, the complexity is reduced by separating physical parameters and electrical parameters and identifying controllable parameters and given parameters. This paper first introduces parameters which are used in the coupling equations and automotive wiring design, then the coupling noise calculation method which uses the coupling equations is introduced. The systematic automotive wiring guideline which prevents noise problem in various design stage such as system filter design, wire layout design, wire type selection is introduced.
Technical Paper

Development of Ground Level Simulation Tool for Automotive Applications

This paper describes the ground system model and algorithm for a ground level simulation tool. First, the modeling of an automotive ground system will be discussed and the algorithm for a simulation tool will be explained. We divided the model into a ground tree and a ground body. The ground tree model consists of resistance formed by the wires that connect the load to ground point with various structures and the ground body model consists of resistance between ground points in the car body. The wires with large current, such as engine ground cable, was modeled in detail by dividing the resistance into wire, bolt, and clamping resistance, in order to simulate the effect of increased contact resistance after durability test. The algorithm of the ground level simulation tool was designed to adjust the currents of the alternator, battery, and ground points in order to evaluate the various driving and load conditions.
Technical Paper

Software Reuse in Development of In-Vehicle Network Analyzer

In-Vehicle Network (IVN) protocol such as CAN, MOST, Flexray and etc. have been extensively applied in automotive communication systems. Analyzer development for network diagnoses purpose correspondingly becomes an emerging industry in automotive field. To reduce the increasing software development costs for protocol of various types, reusable analyzer software architecture and standardized system composition mechanism are needed. In this paper, we propose reusable analyzer software architecture, a system integrating mechanism and a component replacing policy. We built the reusable architecture by extracting similarities of different analyzer development. In system integrating phase, components are abstracted so that they can be located, compared and selected by system integrators. And component replacing policy is used to reuse the software for new analyzer development.
Technical Paper

Wire Segment Error Locating Algorithm for Wiring Connection Verification Tool

Due to increasing amount of modules and customized options in commercial vehicles, it becomes more and more difficult to verify the circuit design. In this paper, a wire segment error locating algorithm is proposed to automate the exact wire segment error locating process. When a wrong connection is found by existing tool, guided by the exact description of wire segment error, this algorithm can locate exact wire segment error in the connection by searching for the one that has at least one neighboring segment from a correct connection.
Technical Paper

An Evaluation Algorithm of IPS in Automotive Application

Currently Intelligent Power Switch (IPS) is substituting the fuse and relay in automotive electronic systems due to its simplicity in design, assembly, and maintenance as well as its advantages of cost reduction. As the percentage of IPS in automotive power system gets higher, the stability and credibility of the automotive power system depends more by IPS evaluation. Since IPS is semiconductor device, the performance is more influenced by its ambient temperature than replacing fuses and relays. As reliability is one of the most important characteristics in automotive system, wire protection, over-current protection, and short-circuit protection should be considered. The evaluation algorithm of IPS must include these characteristics. This paper describes the algorithm development of effective IPS (Intelligent Power Switch) evaluation software for automotive applications.
Technical Paper

A study on Reducing the Computing Burden of Misfire Detection using a Conditional Monitoring Method

This paper presents a conditional misfire monitoring method to reduce the computing burden of the motoring. In this conditional monitoring method, the ECU performs misfire detection only when there is high probability of misfire events. The condition for performing the misfire detection is determined by the pre-index which is defined as the deviation of the segment durations of the crankshaft in this paper. The quantity of the code of calculating the pre-index is 7 times less than that of a conventional monitoring method so that the computing burden can be reduced with the conditional monitoring method. The experimental results shown that the pre-index and the conditional monitoring method are valid.