Actuator Fault Diagnosis with Application to a Diesel Engine Testbed

This work addresses the issues of actuator fault detection and isolation for diesel engines. We are particularly interested in faults affecting the exhaust gas recirculation (EGR) and the variable geometry turbocharger (VGT) actuator valves. A bank of observer-based residuals is designed using a nonlinear mean value model of diesel engines. Each residual on the proposed scheme is based on a nonlinear unknown input observer and designed to be insensitive to only one fault. By using this scheme, each actuator fault can be easily isolated since only one residual goes to zero while the others do not. A decision algorithm based on multi-CUSUM is used. The performances of the proposed approach are shown through a real application to a Caterpillar 3126b engine

A novel fuzzy logic variable geometry turbocharger and exhaust gas recirculation control scheme for optimizing the performance and emissions of a diesel engine

Variable geometry turbocharger and exhaust gas recirculation valves are widely installed on diesel engines to allow optimized control of intake air mass flow and exhaust gas recirculation ratio. The positions of variable geometry turbocharger vanes and exhaust gas recirculation valve are predominantly regulated by dual-loop proportional–integral–derivative controllers to achieve predefined set-points of intake air pressure and exhaust gas recirculation mass flow. The set-points are determined by extensive mapping of the intake air pressure and exhaust gas recirculation mass flow against various engine speeds and loads concerning engine performance and emissions. However, due to the inherent nonlinearities of diesel engines and the strong interferences between variable geometry turbocharger and exhaust gas recirculation, an extensive map of gains for the P, I, and D terms of the proportional–integral–derivative controllers is required to achieve desired control performance. The present simulation study proposes a novel fuzzy logic control scheme to determine appropriate positions of variable geometry turbocharger vanes and exhaust gas recirculation valve in real-time. Once determined, the actual positions of the vanes and valve are regulated by two local proportional–integral–derivative controllers. The fuzzy logic control rules are derived based on an understanding of the interactions among the variable geometry turbocharger, exhaust gas recirculation, and diesel engine. The results obtained from an experimentally validated one-dimensional transient diesel engine model showed that the proposed fuzzy logic control scheme is capable of efficiently optimizing variable geometry turbocharger and exhaust gas recirculation positions under transient engine operating conditions in real-time. Compared to the baseline proportional–integral–derivative controllers approach, both engine’s efficiency and total turbo efficiency have been improved by the proposed fuzzy logic control scheme while NOx and soot emissions have been significantly reduced by 34% and 82%, respectively

A Numerical Study of the Effects of Oxy-Fuel Combustion under Homogeneous Charge Compression Ignition Regime

The European Union (EU) has recently adopted new directives to reduce the level of pollutant emissions from non-road mobile machinery engines. The main scope of project RIVER for which this study is relating is to develop possible solutions to achieve nitrogen-free combustion and zero-carbon emissions in diesel engines. RIVER aims to apply an oxy-fuel combustion with Carbon Capture and Storage (CCS) technology to eliminate NOx emission and to capture and store carbon emissions. As part of this project, a computational fluid dynamic (CFD) analysis has been performed to investigate the effects of oxy-fuel combustion on combustion characteristics and engine operating conditions in a diesel engine under Homogenous Charge Compression Ignition (HCCI) mode. A reduced chemical n-heptane-n-butanol-PAH mechanism which consists of 76 species and 349 reactions has been applied for oxy-fuel HCCI combustion modeling. Different diluent strategies based on the volume fraction of oxygen and a diluent gas has been considered over a wide range of air-fuel equivalence ratios. Variation in the diluent ratio has been achieved by adding different percentages of carbon dioxide for a range from 77 to 83 vol. % in the intake charge. Results show that indicated thermal efficiency (ITE) has reduced from 32.7% to 20.9% as the CO2 concentration has increased from 77% to 83% at low engine loads while it doesn’t bring any remarkable change at high engine loads. It has also found that this technology has brought CO and PM emissions to very ultra-low level (near zero) while NOx emissions have been completely eliminated

Effects of Intake Charge Temperature on Oxy-Fuel Combustion (OFC) in an HCCI Diesel Engine under Different CO2 Dilutions

Carbon dioxide is one of the leading contributors to global warming. Oxy-fuel combustion (OFC) integrated with Carbon Capture and Storage (CCS) technology is an efficient way to reduce carbon dioxide emissions. In OFC, pure oxygen is used instead of air to react with hydrocarbon fuel. Consequently, the products of combustion mainly include CO2 and water vapor (H2O) under lean conditions. Meanwhile, due to the absence of N2 in the intake charge, nitrogen-related emissions such as NOx are greatly removed from the exhaust gases. In the present study, the effect of intake charge temperature on OFC has been investigated in a diesel engine under the Homogeneous Charge Compression Ignition (HCCI) mode. In order to control combustion temperature and avoid overheating problems caused by pure oxygen in OFC, a portion of the exhaust CO2 was added to the oxygen. For this purpose, different CO2 dilutions ranging from 79-85% have been employed. It has been found that OFC can significantly reduce CO and PM emissions while eliminating NOx emissions. With a higher intake charge temperature, combustion occurs earlier with shorter main stages, reducing the Indicated Mean Effective Pressure (IMEP) and increasing the Indicated Specific Fuel Consumption (ISFC), whereas, with a lower intake charge temperature, combustion stability deteriorates leading to incomplete OFC. By raising the intake charge temperature from 140°C to 220°C and applying 21% O2 and 79% CO2 v/v, the Indicated Thermal Efficiency (ITE) is increased by 34.6%. However, ISFC is adversely affected by 18%

Implementation of Oxy-Fuel Combustion (OFC) technology in a Gasoline Direct Injection (GDI) engine fuelled with gasoline-ethanol blends

Nowadays, to mitigate the global warming problem, the requirement of carbon neutrality has become more urgent. Oxy-Fuel Combustion (OFC) has been proposed as a promising way of Carbon Capture and Storage (CCS) to eliminate Carbon Dioxide (CO2) emissions. This article explores the implementation of OFC technology in a practical Gasoline Direct Injection (GDI) engine fuelled with gasoline-ethanol blends, including E0 (gasoline), E25 (25% ethanol, 75% is gasoline in mass fraction) and E50 (50% ethanol, 50% is gasoline in mass fraction). The results show that with a fixed spark timing

Comparative investigation on macroscopic and microscopic characteristics of impingement spray of gasoline and ethanol from a GDI injector under injection pressure up to 50 MPa

Particulate Matter (PM) emissions from passenger vehicles have attracted considerable interest over the last decade. In order to reduce PM emissions, improving maximum injection pressure has been a developing trend for new generation GDI engines. However, comparing gasoline and ethanol impingement spray characteristics from a GDI injector under high injection pressure is still unclear. In this paper, a comparative investigation on both the macroscopic and microscopic characteristics of impingement spray from a GDI injector fuelled with gasoline and ethanol was performed under injection pressure up to 50 MPa, providing new findings to promote a more homogeneous air-fuel mixture and reduce PM emissions. The experimental results show that under the sam

Exploring the potential benefits of Ethanol Direct Injection (EDI) timing and pressure on particulate emission characteristics in a Dual-Fuel Spark Ignition (DFSI) engine

Nowadays, particulate matter emitted by vehicles severely impacts environmental quality and human health. In this paper, the potential benefits of Ethanol Direct Injection (EDI) timing and pressure on particulate emission characteristics in a Dual-Fuel Spark Ignition (DFSI) engine were initially and systematically explored. The experimental results illustrate that by delaying EDI timing from -340 ºCA to -300 ºCA, there is a significant benefit in both particulate number and mass concentration. Furthermore, the size distribution curve of particulate number changes from bimodal to unimodal, meantime size distribution curves of particulate mass consistently concentrate on the accumulation mode. By increasing EDI pressure from 5.5 MPa to 18 MPa, the droplet size of ethanol spray can be effectively reduced. The benefit of increasing EDI pressure is more apparent in reducing particulate number is than particulate mass. The concentration of number and mass for total particulates have a reduction of 51.15% and 22.64%, respectively. In summary, it was demonstrated that an appropriate EDI timing or high EDI pressure could be a practical and efficient way to reduce particulate emissions in a DFSI engine

Tools of Lyapunov Functions for Qualitative Analysis of Time-Switched Linear System

International audienceWe investigate a switched system given by a set of linear systems. We offer the tools of qualitative system analysis using multiple Lyapunov function method and obtain the estimations of system solution at the final time moment depending of initial state. The estimation are obtained by composition of perturbations of the separate subsystems on each time intervals of switched system

CLF-Based Nonlinear Control Design for Turbocharged Diesel Engine

International audienceIn this paper, we propose Control Lyapunov Function based nonlinear robust controller for turbocharged diesel engine. The basic idea is to develop inverse optimal control and utilize more general Lyapunov function which provides additional degree of freedom in order to desire better performance. The obtained controller gain guarantees the global convergence of the Diesel Engine system and regulates flows for the Variable Geometry Turbocharger and Exhaust Gas Recirculation systems in order to optimize oxygen-fuel ratio and intake manifold EGR fraction. Simulation of the control performance shows the effectiveness of this approac