Influence of gas-to-liquid fuel on the combustion and pollutant emission characteristics

Park, Su Han,Lee, Donggon,Lee, Chang Sik Professional Engineering Publishing Ltd 2014 Proceedings of the Institution of Mechanical Engin Vol. No.

<P>The purpose of this work was to investigate the combustion performance and the pollutant emission characteristics of gas-to-liquid fuel in a passenger car’s diesel engine. In order to perform this study, the test facilities were set up on a 1.6 l four-cylinder compression ignition diesel engine with a common-rail injection system. Gas-to-liquid fuel combustion under a high-engine-load condition was compared with conventional diesel and biodiesel derived from soybean oil. The performance test results revealed that the gas-to-liquid fuel shows more rapid ignition than diesel and biodiesel do because of its high cetane number. The rates of increase in the combustion pressure in gas-to-liquid fuel and biodiesel were smaller than that in diesel, and the maximum rate of heat release from gas-to-liquid fuel was the lowest among the three test fuels. In terms of emission analysis, gas-to-liquid fuel shows a slight decrease in the nitrogen oxide emissions and significant reductions in the hydrocarbon and the carbon monoxide emissions compared with other test fuels. Meanwhile, the combustion of gas-to-liquid fuel indicates a lower concentration of soot emissions than those from conventional diesel but slightly higher than those from biodiesel owing to the variation in the low heating value parameter.</P>

Observer design for exhaust gas recirculation rate estimation in a variable-geometry turbocharger diesel engine using a model reference identification scheme

Lee, Hyunjun,Park, Yeongseop,Sunwoo, Myoungho Professional Engineering Publishing Ltd 2014 Proceedings of the Institution of Mechanical Engin Vol. No.

<P>Exhaust gas recirculation systems are used in diesel engines to reduce nitrogen oxide emissions. Since excessive recirculation in the cylinders may lead to an increase in generation of particulate matter and to unstable combustion, the exhaust gas recirculation rate should be measured correctly and should be controlled precisely. Unfortunately, the harsh conditions of the exhaust gas recirculation path make it difficult to measure the exhaust gas recirculation mass flow rate directly by using the relevant sensors. Therefore, precise control of the exhaust gas recirculation system depends on accurate estimation of the exhaust gas recirculation rate. To estimate accurately the exhaust gas recirculation rate in a turbocharged diesel engine, we propose an observer based on a model reference identification scheme. A linear parameter-varying model of the intake manifold pressure was derived to serve as the observer’s reference model. An update rule of the observer was designed with the model reference identification scheme. The intake and exhaust temperature models were developed through an empirical approach. Convergence of the proposed observer was proven in terms of the Lyapunov stability criterion. The proposed observer was implemented on a real-time embedded system and validated successfully through experiments on the engine.</P>

Effect of additives on ignition of methane at homogeneous charge compression ignition engine-like conditions

Morsy, M. H.,Chung, S. H. Professional Engineering Publishing Ltd 2007 Proceedings of the Institution of Mechanical Engin Vol.221 No.5

Evaluation of the time-resolved nanoparticle emissions and the vehicle performance characteristics for a turbocharged gasoline direct-injection vehicle with a metal-foam gasoline particulate filter

Baek, Sungha,Jin, Dongyoung,Jang, Wonwook,Myung, Cha-Lee,Park, Simsoo,Lee, Jeongmin Professional Engineering Publishing Ltd 2016 Proceedings of the Institution of Mechanical Engin Vol. No.

<P>The nanoparticle emissions from gasoline direct-injection engines are of concern because of the high particle number concentrations compared with those from a gasoline port fuel injection engine. A gasoline particulate filter is a potential solution for reducing the particulate matter emissions. In this study, a 2.0 l turbocharged gasoline direct-injection vehicle with a metal-foam-type gasoline particulate filter was tested using the New European Driving Cycle and steady vehicle operating conditions. The particle number concentration, the particle-size distribution and the filtration efficiency were determined using a condensation particle counter and a fast response differential mobility spectrometer (DMS500). The particle number emissions (particle numbers per vehicle travelling distance (particles/km)) over the New European Driving Cycle were 1.95x10(12) particles/km for a base vehicle equipped with a three-way catalytic converter and 5.68x10(11) particles/km for the additional installation of a gasoline particulate filter on the base gasoline direct-injection vehicle. The filtration efficiency of the particle number and the particulate matter mass reached approximately 71% and 67% respectively. The nucleation-mode particles in the size range less than 23nm for the gasoline direct-injection vehicle equipped with a three-way catalytic converter were further reduced on installation of a gasoline particulate filter at the downstream position of the three-way catalytic converter. A sharp pressure drop between the gasoline particulate filter of 21.0 mbar was obtained at a vehicle speed of 120km/h in the New European Driving Cycle. The exhaust gas temperature before the gasoline particulate filter reached around 380-610 degrees C at steady vehicle speeds of 60-120km/h. The installation of the gasoline particulate filter has the potential to satisfy the Euro 6c particle number emissions regulations for light-duty gasoline direct-injection vehicles.</P>

Static characteristics of a bellows-type flow regulator for the thrust control of a liquid rocket engine

Professional Engineering Publishing Ltd 2014 Proceedings of the Institution of Mechanical Engin Vol. No.

<P>A novel bellows-type flow regulator was designed with the ability to maintain a steady thrust level and to adjust the thrust of a liquid rocket engine. The flow regulator showed good performance not only in maintaining the flow rate despite changes in the pressure difference across the flow regulator, but also in adjusting the flow rate in response to a changing shaft angle. A mathematical static model of the flow regulator was developed. A design criterion for ideal performance of the flow regulator was derived by theoretical analysis of the mathematical model. It was established that the main design parameters of the flow regulator affecting flow rate maintenance were the number and the width of ports in the 2nd throttle. The static characteristics predicted by the mathematical model show good agreement with experimental results, thus validating the mathematical model.</P>

The effects of the combustion chamber geometry and a double-row nozzle on the diesel engine emissions

Choi, Seungmok,Shin, Seung-Hyup,Lee, Jeongwoo,Min, Kyoungdoug,Choi, Hoimyung Professional Engineering Publishing Ltd 2015 Proceedings of the Institution of Mechanical Engin Vol. No.

<P>This paper presents how injector nozzle distributions and the combustion chamber geometry affect the emission characteristics of diesel engines. The number of nozzle holes was increased from seven to 12 by a using double-row nozzle distribution to enhance the air–fuel mixing and the spatial distribution of the spray while avoiding spray overlap. The combustion chamber geometry was modified to have a wide shallow two-step bowl, which ensured adequate spray penetration with the double-row nozzle, to observe the influence of the spray–piston interaction on the combustion and emissions. Three hardware combinations (a seven-hole single-row nozzle with a conventional piston, a 12-hole double-row nozzle with a conventional piston, and a two-step piston) were tested in a single-cylinder direct-injection diesel engine under three boost and exhaust gas recirculation conditions. The injection timing was adjusted to result in a similar power by maintaining 50% of the total fuel mass fraction burned points for each hardware combination. For a conventional boost pressure (1.10 bar) and 30% exhaust gas recirculation, the 12-hole double-row nozzle with a conventional piston exhibited the best emission characteristics with a significant reduction in the particulate matter emissions. For a high boost pressure (1.30 bar) and 30% conventional exhaust gas recirculation, the nitrogen oxide emissions slightly increased and the particulate matter emissions decreased for the 12-hole double-row nozzle with a conventional piston compared with those for the seven-hole single-row nozzle. The two-step piston resulted in decreased particulate matter emissions but increased nitrogen oxide emissions under a high boost pressure. For 60% high exhaust gas recirculation, which is characterized by low-temperature combustion, the particulate matter emissions, the carbon monoxide emissions, and the total hydrocarbon emissions decreased simultaneously without an increase in the nitrogen oxide emissions using the 12-hole double-row nozzle with a two-step piston.</P>

Design of a novel adaptive fuzzy sliding mode controller and application for vibration control of magnetorheological mount

Phu, Do Xuan,Quoc, Nguyen Vien,Park, Joon-Hee,Choi, Seung-Bok Professional Engineering Publishing Ltd 2014 Proceedings of the Institution of Mechanical Engin Vol. No.

<P>This paper presents vibration control of a mixed-mode magnetorheological fluid-based mount system using a new robust fuzzy sliding mode controller. A novel model of controller is built based on adaptive hybrid control of interval type 2 fuzzy controller incorporating with a new modified sliding mode control. The interval type 2 fuzzy is optimized for computational cost by using enhanced iterative algorithm with stop condition, and a new modified switching surface of sliding mode control is designed for preventing the chattering of the system. The controller is then experimentally implemented under uncertain conditions in order to evaluate robust vibration control performance. In addition, in order to demonstrate the effectiveness of the proposed controller, two fuzzy sliding mode control algorithms proposed by Huang and Chan are adopted and modified. The principal control parameters of three controllers are updated online by adaptation laws to meet requirements of magnetorheological mount system which has two operation modes: flow mode and shear mode. It is shown from experimental realization of three controllers that the proposed control strategy performs the best under uncertain conditions compared with two other modified controllers. This merit is verified by presenting vibration control performances in both time and frequency domains.</P>

Parallel singularity-free design with actuation redundancy: A case study of three different types of 3-degree-of-freedom parallel mechanisms with redundant actuation

Shin, Kyoosik,Yi, Byung-Ju,Kim, Wheekuk Professional Engineering Publishing Ltd 2014 Proceedings of the Institution of Mechanical Engin Vol. No.

<P>Typical parallel mechanisms suffer from parallel singularity due to kinematic coupling of multichains. This paper investigates how to remove parallel singularities by using redundant actuations. First, actuation wrenches and constraint wrenches forming the full direct kinematic Jacobian matrix are derived. After briefly addressing conditions for their constraint singularities, Grassmann–Cayley algebra is employed to identify parallel singularities. Then, employing Grassmann line geometry, the locations and the minimum number of redundant actuators are identified for the parallel mechanisms to have parallel singularity-free workspace. Three different types of 3-degree-of-freedom parallel mechanisms such as planar, spherical, and spatial parallel mechanisms are given as exemplary devices.</P>

Integrated differential braking and electric power steering control for advanced lane-change assist systems

Park, Manbok,Lee, Sanghyun,Kim, Myoungjune,Lee, Junyung,Yi, Kyongsu Professional Engineering Publishing Ltd 2015 Proceedings of the Institution of Mechanical Engin Vol. No.

<P>This paper describes the design and verification of a control algorithm for advanced lane-change assist systems with integrated control of the differential braking and the electric power steering system. The objective of the proposed control algorithm of the advanced lane-change assist system is to minimize the unexpected control input of electric power steering and to make maximum use of the differential brake effort. The advanced lane-change assist system can warn of potential rear and side crashes and prevent collisions in lane-change manoeuvres with active intervention when there is an upcoming vehicle with a potential risk to the rear in the next lane. An enhanced lane-change assist warning algorithm is developed with additional information on the estimated past trajectory of the subject vehicle. The upper controller of the advanced lane-change assist system determines the control on–off decision, the desired yaw rate for collision avoidance and the strategic control input distribution. The key strategy of this integrated control algorithm is to use the maximum tyre–road friction of the differential brake force and to operate with a smaller control effort of the electric power steering only when lacking in the level of yaw rate moment obtained by the electronic stability control, which is intended to minimize annoyance to a driver and control intervention. The lower controller decides the control input of the advanced electronic stability control and the electric power steering system. Finally the advanced lane-change assist system is implemented in a real vehicle and tested in both the steering-control-only case and the integrated-control case. It is shown that the proposed strategy can intervene appropriately and verifies the effectiveness of collision avoidance in a dangerous lane-change situation; a decrease in the electric power steering control input of about 20% can be achieved by the proposed algorithm.</P>

The effect of different forming parameters on the depth of bipolar-plate channels in static- and dynamic-load stamping

Kim, Min June,Jin, Chul Kyu,Kang, Chung Gil Professional Engineering Publishing Ltd. 2015 Proceedings of the Institution of Mechanical Engin Vol. No.

<P>A titanium alloy is selected as an ideal material for a fuel-cell bipolar plate because it has a low density and, like aluminium, exhibits excellent corrosion resistance due to an insulating oxide film. Microchannelled bipolar plates are fabricated using a 25-ton material-testing machine by varying the parameters of the static and dynamic loads (type of load wave, punch load, number of cycles) and the die curvature in order to evaluate the formability. The bipolar plate formed by dynamic-load stamping (square wave of 0.5 Hz, 32 load cycles, punch load of 90 kN) with die curvature of 0.3 mm resulted in 13.0% deeper channels compared to static-load stamping of 90 kN. Moreover, in the case of 0.1 mm die curvature, the bipolar plate formed by square-wave dynamic-load stamping had 22.7% deeper channels, compared to static-load stamping. Dynamic-load stamping with die curvatures of 0.1 and 0.3 mm shows a channel depth of 0.251 and 0.353 mm, respectively. Compared to die curvature of 0.1 mm, 0.3 mm die curvature resulted in channels that are deeper by 28.9%.</P>