Engine dynamic signal monitoring and diagnostics.

A study was undertaken to determine the feasibility of developing an engine dynamic signal monitoring and diagnostic system for use on-line in a high volume engine manufacturing plant as well as in a research environment for the development of new engine components. The system will enable rapid and precise diagnostics of the production engine for identifying and locating manufacturing or assembly defects which do not include thermodynamics, combustion/or emission related defects. Recently published literature on engine noise and vibration monitoring and diagnostic systems is reviewed with special emphasis on the use of noise and vibration for on-line monitoring and diagnosing. A complete bibliography of 175 references is appended, together with the summary chart outlining the subject classified by topics. The feasibility of using noise and vibration for the detection of engine manufacturing and assembly defects as well as evaluating the effectiveness of component design changes, was originally carried out in the dynamometer laboratory. Here, customer returned engines were evaluated for noise and vibration using three different monitoring systems developed for the same purposes. In these systems accelerometers, microphones and pressure transducers were used in conjunction with both a conventional dynamic signal analyzer and a specially designed eight channel data acquisition system coupled with custom designed computer programs. All these systems are capable of detecting defects in customer returned engines. Detail reviews were carried out emphasizing the advantages and disadvantages of each system. The noise and vibration measurements were then correlated with actual manufacturing and assembly defects. The systems were also tested for evaluating the noise and vibration characteristics of changes in piston design. With the success in diagnosing customer returned engines, a field study was undertaken to determine the feasibility of using noise and vibration for detecting missing connecting rod bearings, loose connecting rod nuts, and other related manufacturing/assembly defects. A modified monitoring system which includes accelerometers and microphones together with a uniquely designed data acquisition system was used to obtain the noise and vibration data. In the initial phase, data was collected from fifteen partially completed engines having different defects. These were then analyzed to set the vibration limits for rejection. The on-line engine monitoring and diagnostic system was implemented and it was observed that in the test of more than 120,000 engines, the success rate in reduction of defective engines was 100 percent. Thus it was concluded that the monitoring system with a specially designed data acquisition system is capable of on-line monitoring and rapid and precise diagnosing of production engines with manufacturing and/or assembly defects. The system is also well suited for use in evaluating the noise and vibration characteristics of any engine when one or more of its components has undergone design changes.Dept. of Mechanical, Automotive, and Materials Engineering. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis1993 .T565. Source: Dissertation Abstracts International, Volume: 54-09, Section: B, page: 4798. Adviser: Z. F. Reif. Thesis (Ph.D.)--University of Windsor (Canada), 1993

Wear mechanism evolution on brake discs for reduced wear and particulate emissions

Brake disc wear contributes heavily to particulate matter as non-exhaust emission in the transportation sector. To tackle this issue, research on this topic has so far been directed at obtaining a hard and dense disc surface to reduce abrasive wear. The present research manipulates the disc surface morphology so that an adhesive transfer layer can be formed during sliding to protect the disc from wear. The designed interlocking surface was prepared using plasma electrolytic aluminating (PEA) process. A non asbestos organic (NAO) brake pad was used for tribotests. The results showed that the PEA-treated brake disc exhibited negligible wear because of the thin protective layer generated by the pad material transfer onto the PEA-treated cast iron. The dimple-like surface, produced through the PEA process, enhanced the bonding of the transfer layer due to mechanical interlocking. The coated surface increased the coefficient of friction of the disc to some extent. The surface also resulted in a reduced wear rate of the brake pad, highlighting the potential for the PEA process to enable reduced wear debris and thus non-exhaust emission through an altered wear mechanism in future brake disc applications.</p

Spark-based Advanced Ignition Control for Future Diluted Gasoline Engines

To meet the mandatory CO2 emissions regulations in the future, current gasoline engines require significant work for efficiency improvement. One critical part of combustion optimization is to improve the spark ignition process, especially for the engines that utilize charge dilution concept incorporated with strong cylinder flow. Such high efficiency combustion process requires the ignition systems to effectively ignite the mixture and secure the flame kernel until developing to self-sustainable propagation. In this paper, the extent of spark stretching and the ability to withhold from restrike in high-speed flow are investigated for various sparking strategies. A thick plasma channel that is generated by boosted glow current is less prone to be blown off by the strong flow, consequently, the restrike frequency is lowered. In comparison with a low current long lasting spark generated by the dual-coil continuous discharge strategy, the boosted current strategy can lead to a faster flame kernel growth. Single-cylinder engine experiments indicate that the combustion phasing controllability and the stability of lean/diluted engine operation can be improved by using the boosted current ignition strategies with conventional spark plug. Extensive engine test results indicate that the multi-core ignition can better control the gasoline combustion and extend the operable limits of lean/diluted engine combustion, compared with single-pole ignition for low to medium engine loads. Experimental results indicate that the multi-core ignition strategy, even with lower current on each pole, have clear advantages over the high current single-pole strategies such as the multi-coil ignition and the boosted current ignition, with respect to the combustion phasing controllability of super lean gasoline combustion. Multiple-cylinder production gasoline engine test results show that the multi-core ignition can improve the stability of gasoline engine at high levels of dilution, thereby leading to improvement of indicated specific fuel consumption

Intelligent Detection and Real-time Monitoring of Engine Oil Aeration Using a Machine Learning Model

This research work develops a machine learning model for detecting and real-time monitoring engine oil aeration in an internal combustion engine using only single high-speed oil pressure sensor. The presented method uses a five level cascading discrete wavelet transform with Daubechies 4 tap wavelet and an associated variance metric to identify features related to oil aeration from a set of recorded oil pressure traces. A Gaussian process regression model is then used to correlate the identified features to measured oil aeration and the presented approach is successfully able to predict engine oil aeration to an uncertainty of under ±0.02 from the measured oil aeration values. The sensitivity of this method to varying sampling frequencies is also tested and the method is found to be successful over a wide range of sampling frequencies. This method of predicting measured oil aeration using a single high-speed oil pressure sensor has the benefit of monitoring engine oil aeration without the need for direct measurement

Numerical and Experimental Validation of Natural Fiber Orientation in Viscous Fluid of Injection Cavity

In an injection moulded product, the orientation of short fiber in polymer composite influences the strength of the product. A method was developed to predict orientation of natural fiber in thermoset composite. The purpose of this investigation is to predict the orientation of natural fiber in a viscous fluid and to study fiber flow in mould cavity. An experimental set up was developed on injecting viscous fluid with short natural inside the transparent mould cavity and visualize the orientation of short natural fiber and flow front during filling period of cavity. The proposed model for natural fiber orientation was derived by coupling the tangential orientation of natural fiber in flow front and constant curling factor in angular velocity of fluid element. The orientation angle was predicted through proposed model at specified position and was validated with experimental method through digitized image analysis technique

Implementation Challenges and Solutions for Homogenous Charge Compression Ignition Combustion in Diesel Engines

Homogenous charge compression ignition (HCCI) combustion in diesel engines can provide for cleaner operation with ultra-low NOx and soot emissions. While HCCI combustion has generated significant attention in the last decade, however, to date, it has seen very limited application in production diesel engines. HCCI combustion is typically characterized by earlier than top-dead-center (pre-TDC) phasing, very high pressure rise rates, short combustion durations and minimal control over the timing of the combustion event. To offset the high reactivity of the diesel fuel, large amounts of EGR (30 to 60%) are usually applied to postpone the initiation of combustion, shift the combustion towards TDC and alleviate to some extent, the high pressure rise rates and the reduced energy efficiency. In this work, a detailed analysis of HCCI combustion has been carried out on a high-compression ratio, single-cylinder diesel engine. The effects of intake boost, EGR quantity/temperature, engine speed, injection scheduling and injection pressure on the operability limits have been empirically determined and correlated with the combustion stability, emissions and performance metrics. The empirical investigation is extended to assess the suitability of common alternate fuels (n-butanol, gasoline and ethanol) for HCCI combustion. On the basis of the analysis, the significant challenges affecting the real-world application of HCCI are identified, their effects on the engine performance quantified and possible solutions to overcome these challenges explored through both theoretical and empirical investigations. This paper intends to provide a comprehensive summary of the implementation issues affecting HCCI combustion in diesel engines

Adaptive Smooth Variable Structure Filter Strategy for State Estimation of Electric Vehicle Batteries

Battery Management Systems (BMSs) are used to manage the utilization of batteries and their operation in Electric and Hybrid Vehicles. It is imperative for efficient and safe operation of batteries to be able to accurately estimate the State of Charge (SoC), State of Health (SoH) and State of Power (SoP). The SoC and SoH estimation must remain robust and accurate despite aging and in presence of noise, uncertainties and sensor biases. This paper introduces a robust adaptive filter referred to as the Adaptive Smooth Variable Structure Filter with a time-varying Boundary Layer (ASVSF-VBL) for the estimation of the SoC and SoH in electrified vehicles. The internal model of the filter is a third-order equivalent circuit model (ECM) and its state vector is augmented to enable estimation of the internal resistance and current bias. It is shown that system and measurement noise covariance adaptation for the SVSF-VBL approach improves the performance in state estimation of a battery. The estimated internal resistance is then utilized to improve determination of the battery’s SoH. The effectiveness of the proposed method is validated using experimental data from tests on Lithium Polymer automotive batteries. The results indicate that the SoC estimation error can remain within less than 2% over the full operating range of SoC along with an accurate estimation of SoH

Implementation challenges and solutions for homogeneous charge compression ignition combustion in diesel engines

Homogeneous charge compression ignition (HCCI) combustion in diesel engines can provide cleaner operation with ultralow NOx and soot emissions. While HCCI combustion has generated significant attention in the last decade, however, till date, it has seen very limited application in production diesel engines. HCCI combustion is typically characterized by earlier than top-dead-center (pre-TDC) phasing, very high-pressure rise rates, short combustion durations, and minimal control over the timing of the combustion event. To offset the high reactivity of the diesel fuel, large amounts of exhaust gas recirculation (EGR) (30-60%) are usually applied to postpone the initiation of combustion, shift the combustion toward TDC, and alleviate to some extent, the high-pressure rise rates and the reduced energy efficiency. In this work, a detailed analysis of HCCI combustion has been carried out on a high-compression ratio (CR), single-cylinder diesel engine. The effects of intake boost, EGR quantity/temperature, engine speed, injection scheduling, and injection pressure on the operability limits have been empirically determined and correlated with the combustion stability, emissions, and performance metrics. The empirical investigation is extended to assess the suitability of common alternate fuels (n-butanol, gasoline, and ethanol) for HCCI combustion. On the basis of the analysis, the significant challenges affecting the real-world application of HCCI are identified, their effects on the engine performance quantified, and possible solutions to overcome these challenges explored through both theoretical and empirical investigations. This paper intends to provide a comprehensive summary of the implementation issues affecting HCCI combustion in diesel engines

Effect of Natural Fiber Network on Permeability and Tensile Strength of Composites through Vacuum Infusion Process

This investigation is primarily focused to study the effect of fiber network on the permeability in vacuum infusion molding process. The unsaturated permeability of several natural fiber mats with different networks is measured. The experimental permeabilities are fitted by the Kozeny model and contact angle model. The outcome highlighted that the contact angle model shows more precise results as compared to kozeny model. The obtained permeability for the random fiber mats shows higher values than directional fiber mat. Furthermore, the maximum increase in tensile strength is observed in the unidirectional composites and the flow along the fiber direction

Implementation Challenges and Solutions for Homogeneous Charge Compression Ignition Combustion in Diesel Engines

Homogeneous charge compression ignition (HCCI) combustion in diesel engines can provide cleaner operation with ultralow NOx and soot emissions. While HCCI combustion has generated significant attention in the last decade, however, till date, it has seen very limited application in production diesel engines. HCCI combustion is typically characterized by earlier than top-dead-center (pre-TDC) phasing, very high-pressure rise rates, short combustion durations, and minimal control over the timing of the combustion event. To offset the high reactivity of the diesel fuel, large amounts of exhaust gas recirculation (EGR) (30-60%) are usually applied to postpone the initiation of combustion, shift the combustion toward TDC, and alleviate to some extent, the high-pressure rise rates and the reduced energy efficiency. In this work, a detailed analysis of HCCI combustion has been carried out on a high-compression ratio (CR), single-cylinder diesel engine. The effects of intake boost, EGR quantity/temperature, engine speed, injection scheduling, and injection pressure on the operability limits have been empirically determined and correlated with the combustion stability, emissions, and performance metrics. The empirical investigation is extended to assess the suitability of common alternate fuels (n-butanol, gasoline, and ethanol) for HCCI combustion. On the basis of the analysis, the significant challenges affecting the real-world application of HCCI are identified, their effects on the engine performance quantified, and possible solutions to overcome these challenges explored through both theoretical and empirical investigations. This paper intends to provide a comprehensive summary of the implementation issues affecting HCCI combustion in diesel engines