EGR System Research Articles

Monitoring of the states of malfunction of the EGR system in TDCi engines fueled with Ekodiesel Ultra and B10 fuel

The paper discusses the identification of malfunctions in the EGR system based on a list of OBD II error codes. The authors monitored EGR systems of vehicles fitted with DURATORQ TDCi engines. The Analysis of the processes of heat transfer and mass exchange in the engine intake system drew attention to a number of simplifications in the formal description introducing a wide range of tolerance for the instantaneous recirculation rate. The aim of this study was to determine the influence of diesel oil, Ekodiesel Ultra with biocomponents and B10 fuel used for the fueling of diesel engines on the formation of deposits in the EGR system. The analysis was performed in a laboratory utilizing the methods of energy dispersive X-ray fluorescence and infrared spectroscopy.

静電サイクロン方式 DPF の開発 - 高効率・コンパクト化とトータル排ガス処理システムの検討

The authors have newly developed an Electrostatic Cyclone DPF to reduce PM emission in diesel exhaust. The PM collection test with the DPF was investigated using two types of marine diesel engines, i.e., a low speed two-stroke engine (3UEC37LA, 1105 kW, 188 rpm) and a high speed four-stroke engine （3L13AHS, 74 kW, 1200 rpm）. Two types of fuels, MDO with a sulfur content of 0.07 % and HFO with a sulfur content of 2.2 %, were used for the tests. The results of the tests are as follows: (1) The Electrostatic Cyclone DPF can reduce PM emission by over 90 %. The DPF has high collection efficiency not only for soot but also for sulfate and soluble organic fraction (SOF) in PM. (2) The PM collection efficiency for HFO was higher than that for MDO; therefore it was confirmed that the DPF is applicable to marine diesel engines operated with HFO. (3) The majority of the PM particles have diameters less than 500nm, and the PM collection efficiency for particles smaller than 100nm is greater than 95 %. (4) An exhaust gas processing system which can reduce PM, SOx and NOx is realized by application of the DPF. The proposed exhaust gas processing system consists of the DPF, the scrubber and the EGR system.

Simultaneous Air Fraction and Low-Pressure EGR Mass Flow Rate Estimation for Diesel Engines

This paper describes a low-pressure exhaust gas recirculation (LP-EGR) mass flow rate estimation method and a robust air mass fraction observer for a Diesel engine with dual-loop EGR system. Both observers operate simultaneously eliminating the need for pressure measurement upstream the LP-EGR valve. A sliding mode observer is designed to estimate the LP-EGR mass flow rate using the standard sensors available in commercial Diesel engines. A robust linear parameter varying Kalman filter is designed for the air mass fraction estimation. The convergence and robustness of the observers are ensured by means of Lyapunov stability and a linear matrix inequality (LMI) framework for the sliding mode observer and robust Kalman filter, respectively. The observers are evaluated with a Motor Vehicle Emission Group (NMVEG) cycle using an engine model validated on an experimental benchmark as a reference.

外部EGRシステムによる舶用機関のNOx低減

外部EGRシステムによる舶用機関のNOx低減

Uniportal Endoscopic Gastrocnemius Recession for Treatment of Gastrocnemius Equinus with a Dedicated EGR System with Retractable Blade

This study examined the effectiveness and safety of a uniportal endoscopic gastrocnemius recession with a specifically designed uniportal endoscopic system. Fifty-three patients underwent 60 endoscopic gastrocnemius recessions. Their mean range of ankle dorsiflexion changed from a preoperative value of –2.9° ± 1.9° to a postoperative value of 12.8° ± 1.7°, for a total increase of 15.7° ± 1.8° of ankle dorsiflexion (p < .001). The average time from skin incision to closure was 4 minutes and 19 ± 33.6 seconds. Overall, 4 (6.67%) cases (procedures) were associated with a complication, including 1 (1.67%) case of triceps surae weakness that resolved after physical therapy. Three (5%) cases developed nerve complications, with 2 (3.33%) cases of transient neuritis that spontaneously resolved at 5 and 8 weeks postoperatively, respectively, and 1 (1.67%) that experienced persistent cutaneous anesthesia in the distribution of the sural nerve along the lateral aspect of the foot up to 4 months postoperatively. There were no cases of wound dehiscence or delayed healing, painful scar formation, infection at the surgical site, hematoma, or deep venous thrombosis. Endoscopic gastrocnemius recession with a uniportal system appears to be safe and effective.

Cooled EGR 시스템의 EGR률과 연료분사시기가 소형 디젤엔진의 배기 배출물 특성에 미치는 영향에 관한 연구

Cooled EGR system is widely used to reduce NOx emissions in diesel engine. But when EGR rate was increased, combustion stability was worsened and PM level was increased. So determining optimized control point of EGR rate is important. In order to determine this point, it is important to figure out the effect of EGR system on the exhaust emissions. In this research, NOx and PM emissions were analyzed with various coolant temperature supplied to the EGR cooler at several positions such as downstream of turbocharger, upstream and downstream of DPF. Effects of some variables such as EGR rate, hot / cooled EGR and change of injection timing were estimated. And <TEX>$CO_2$</TEX> emissions were measured at exhaust and intake manifold to calculate EGR rate at each engine operating condition. Also combustion analysis was performed in each engine operating conditions. In the result of this study, there was trade-off between NOx emissions and PM emissions. When EGR rate was increased, combustion pressure was decreased and COV of IMEP was increased.

Study on EGR Control Strategy for Vehicle Diesel Engine Based on Experiment

To carry out electronic control EGR strategy in diesel engine the calculation model using GT-POWER is built. The thesis uses simulation software GT-POWER to establish the calculation model of 4JB1 intake system of turbocharged diesel engine with EGR system and the results agree well. According to the simulation results, it can predict the main performance indicators of the diesel engine when it works at the maximum torque condition, which includes A/F, IMEP, Maximum Pressure, and Intake Pressure and so on. Then after controlling the volume of gas by modifying the EGR valve, it can find out the regulation how EGR effects the engine's emissions, torque, power and the inlet temperature of turbo. Referring to the simulation results, it includes from four aspects：EGR can significantly improve the quality of emission gas; NOx and PM have a trade-off relationship; applying higher EGR rate in heavy load can lead to the low torque and power less; the inlet temperature of turbo increases with the augment of EGR rate. In the experiment, the inlet oxygen concentration method is used to determine the EGR rate, and to realize it, the oxygen concentration detection module is also successful designed. Then a close-loop control strategy is proposed based on the EGR rate. It proves it is feasible to guide the ECU programmer development by the simulation results of engine control strategy. It is also can be referred by other engine control systems development.

Study on the Combustion Process and Emissions of a Turbocharged Diesel Engine with EGR

A high pressure EGR system was adopted to a turbocharged inter-cooled diesel engine, to analyze its combustion and emission characteristics under the condition of different loads and constant speed. Under the same steady operating mode, with the increase of EGR rate, the temperature of compressed gas ascended, the ignition delay was shortened, the pressure and temperature of the burned gas descended, and the combustion process was prolonged. According to the experimental data, it was found that, at the same EGR rate, lower the load of engine was, lower the temperature in cylinder, and higher the increase rate of CO was. However, the increase rate of HC present a falling trend. The decrease rate of the specific emission of NOxlinearly varied with EGR rate with a slope of 1.651. The increase rate of smoke opacity behaved a second-order polynomial uprising trend, and the higher the load was, the sharpener the smoke opacity deteriorated, with the increase of EGR rate. From the point of emission view, the engine with EGR system can achieve the lesser exhaust emissions in some operations by adjusting the engine parameters.

Transient Torque Control of a Diesel Hybrid Powertrain for NOx Limitation

This paper describes a strategy for the reduction of the transient nitrogen oxides (NOx) emissions in a diesel hybrid electric vehicle (HEV). This strategy limits the dynamics of the engine by using the electric motor to maintain the wheel torque demand. Thus, the split ratio between the motor and the engine, initially computed from a steady-state optimal control strategy, is corrected during transient operations where NOx are produced. The engine torque correction relies on mean value models for the EGR system dynamics and for the NOx formation. The strategy is combined with a static EMS and implemented into a software in the loop platform including a detailed engine model with NOx prediction capabilities. This model based approach for the transient engine torque limitation allows a significant NOx reduction with a limited increase in the fuel consumption.

EE2-3 Transient EGR Ratio Measurement by Heated NDIR Method and Analysis of Engine EGR Response Time(EE: Exhaust Emissions and Measurement,General Session Papers)

Most of the recent clean diesel engines are generally equipped with an exhaust recirculation (EGR) technology in order to meet the strict criteria of NOx emission regulations. In the field of emission control, accurate and fast transient EGR ratio operation is becoming very critical. In this study, a transient EGR analyzer has been developed and evaluated with a conventional exhaust gas analyzer system to confirm the advantage of the transient EGR analyzer. As a consequence, the faster response has been observed from the transient EGR analyzer without significant transient error under transient test cycles. The EGR ratio measured by the transient EGR analyzer followed up the EGR valve operation well. These results show the advantages of the transient EGR analyzer for measuring EGR ratio under the transient cycle. Additionally, a simulation of the optimum response time was conducted. The gas transition time of the engine EGR system was simulated by z-transformation using the response time of measured actual exhaust gas. As a result, the optimum response time required to the EGR measurement system was estimated for the test engine.

G090011 筒内燃焼における NO_x ・ SO_x 等排ガス特性

The diesel engine has the high thermal efficiency and can be powered by the various species of fuels. However, the contents of exhaust gas from diesel engine such as NO_x, SO_x, CO_2 and other substances cause to the air pollution. Recently, EGR and Urea SCR is effective as NO_x reduction technology. Fuel desulfurization is existed as SO_x reduction technology. However, sulfur-rich fuels such as C-heavy fuel and asphalt are used mainly on marine diesel. Therefore, new SO_x reduction technology is needed. The objectives of this study is to investigate experimentally the influence on combustion in a diesel engine by mixing N_2, CO_2, CH4, N_2+CH_4, CO_2+CH4 to utilize renewable bio-mass fuels and changing temperature of combustion air to come close to EGR system. Also a study using the thermal non-equilibrium plasma as one of the new reduction methods of NO_x and PM. In this research, it is performed corona discharge to intake air and positive corona or negative corona are produced and intake air is activated by a part of intake air is ionized. The results are obtained as follows. (1)When mixing CH_4 with N_2 or CO_2 with intake air, NO_x and SO_2 concentration is decreased. And CO_2 concentration is higher due tocombustion is improved by mixing CH4. (2)When engine loading rate is higher and intake air is performed negative discharge, it is most effective method as NO_x concentration and SO_2 concentration are reduced.

Study on Effect of Electronically Controlled EGR System on Diesel Engine Performance

This paper designs an electronic control EGR system used in diesel engine and researches the influence of different EGR rate on engine economy and the emission characteristics of the 13- modes cycle. The results show that the specific fuel consumption of the test engine rises at different degrees after using electronically controlled EGR technology, especially in high load areas; NOx emissions have a more significant decline and particles increase to a certain extent; Overall, however, emissions of HC do not nearly change; CO emissions are closely related to EGR rate.

System Properties and Control of Turbocharged Diesel Engines with High-and Low-Pressure EGR

An extension of the air-and exhaust-system with a low-pressure EGR has the potential to significantly reduce the NOx emissions. Besides a cooled high-pressure EGR and the turbocharger with variable geometry turbine, the low-pressure EGR introduces an additional degree of freedom to control the cylinder charge. This increasing complexity of the air system can be handled with model based control structures and a model based controller calibration. Its static and dynamic properties are investigated. Besides the static couplings in the classical air path, additional couplings appear. A decentralised gain scheduled PI(D)-control approach is chosen to control the variables air mass flow rate, high-pressure EGR mass flow rate and charge air pressure. An automated controller calibration, based on a semi-physical mean value model of reduced complexity, is presented. The controller maps depend on the engine operation point and are calibrated by a local linearisation of the semi-physical model. Further, a semi-physical control is capable to almost solely control the air mass flow rate via the low-pressure EGR actuators. This control implicitly accounts for couplings between charge air pressure, high-pressure EGR and the low-pressure EGR system. Finally testbed results are shown.

Performance Analysis of a Turbocharged Heavy Duty Diesel Engine with a Pre-turbo Diesel Particulate Filter Configuration

The use of particulate filters (DPF) has become in recent years the state of the art technology for the reduction of soot aerosol emissions for light, medium and heavy duty Diesel vehicles. However, the effect of the system location on engine performance is a key aspect that should be studied. In the present work a numerical study has been carried out with the objective to analyze the effect on the engine performance of an innovative DPF placement upstream of the turbine. This study has been performed by means of the gas dynamic simulation of a two-stage turbocharged heavy duty Diesel engine, which has been previously modeled from experimental data obtained under steady state conditions. The original DPF has been divided into two monoliths for the case of the pre-turbo DPF configuration. Three cylinders discharge in each of these monoliths and after the filtration the flow is driven towards the high-pressure turbine and the EGR system. The engine response is compared with a pre-turbo DPF configuration under steady state conditions against the common DPF placement downstream of the turbine. The study covers a parametric study based on EGR and waste-gate valves opening. It has allowed comparing the variations on the engine operation as function of the EGR rate and the air-to-fuel ratio settings. Different soot loadings have been considered in order to extend the study over a wider range of operating conditions. Finally, the location of the DOC has been also considered as an additional parameter (upstream of the DPF or downstream of the turbines in the pre-turbo configuration). Results allow identifying the phenomena controlling the engine response when the DPF is placed upstream of the turbines. Among them highlight the increase of the thermal level that favors the passive regeneration, the DPF pressure drop reduction and the benefits that the use of two parallel monoliths brings out regarding the attenuation of the wave interference between cylinders during exhaust valve opening, which leads to make unnecessary the use of twin turbines. The analysis of the interaction among all the involved phenomena provides a comprehensive understanding of the proposed architecture and its potential regarding both the engine and the DPF behavior. Copyright © 2011 SAE International.

비도로 차량용 디젤엔진의 배기가스 저감에 관한 연구

비도로 차량용 디젤엔진의 Tier 4 interim 규제를 만족하기 위하여 입자상물질과 질소산화물 배출량은 현행 규제 대비 각각 95%, 30% 저감되어야 하며, 입자상 물질을 저감하기위한 방법으로 디젤산화촉매, 부분유량 매연 여과장치 및 매연여과장치가 비도로 차량용 디젤엔진에 적용될 수 있다. 또한 질소산화물을 저감하기위해 배기가스 재순환방법, 선택적 환원촉매와 희박 질소산화물 포집장치 등이 적용될 수 있다. 본 연구에서는 56㎾급 off-road 차량에서의 입자상물질과 질소산화물을 저감하기위해 매연여과장치와 고압루프 배기가스재순환 시스템이 연구되었다. 실험결과로서 디젤산화촉매와 매연여과장치는 입자상물질을 저감하는데 매우 효과적이었으며 낮은 배압과 함께 출력손실도 5%이내였다. 고압루프 배기가스재순환을 적용한 결과 중 저부하 조건에서 효과적으로 질소산화물을 저감하였으며 배기가스재순환율이 높을수록 질소산화물의 저감율도 증가하였다.

ETC를 적용한 저압 EGR시스템의 엔진성능 및 배출가스 특성에 관한 연구

Research and development of LP EGR system for the performance improvement and emission reduction on diesel engine is proceeding at a good pace. LP EGR system seems to be helpful method to further reduce emissions while maintaining PM emissions at a low level because the boost pressure is unchanged while varying EGR rate. This study is experimentally conducted on a 2.0L common rail DI engine at the medium load condition (2000 rpm, BMEP 1.0 MPa, boost pressure 181.3 kPa) that difficult to use large amount of EGR gas because of deteriorations of performance and fuel consumption. And we investigated the characteristics of performance and fuel consumption while varying EGR systems. The overall results using LP EGR system equipped with ETC identified benefits on reduction of PM and improvement of fuel consumption and thermal efficiency while keep the level compared to HP EGR and LP EGR with back pressure valve.

Integrated Emission Management strategy for cost-optimal engine-aftertreatment operation

A new cost-based control strategy is presented that optimizes engine-aftertreatment performance under all operating conditions. This Integrated Emission Management strategy minimizes fuel consumption within the set emission limits by on-line adjustment of air management based on the actual state of the exhaust gas aftertreatment system. Following a model-based approach, Integrated Emission Management offers a framework for future control strategy development. This approach alleviates calibration complexity, since it allows to make optimal trade-offs in an operational cost sense. The potential of the presented cost-optimal control strategy is demonstrated for a modern heavy-duty Euro VI engine. The studied diesel engine is equipped with cooled EGR, Variable Geometry Turbocharger, and a DPF-SCR aftertreatment system. A simulation study shows that the proposed Integrated Emission Management strategy accomplishes 2% to 3% reduction in fuel consumption and operating costs compared to a baseline strategy. Further potential benefits include reduced heat rejection associated with the EGR system and reduced DPF regeneration frequency. © 2011 SAE International.

Development of Low Pressure Loop EGR System for Diesel Engines

Development of Low Pressure Loop EGR System for Diesel Engines

Experimental investigation of the influences of shape and surface area on the EGR cooler efficiency

The cooled EGR system is one of the most effective techniques currently available for reducing NOx emissions. In this study, engine dynamometer experiments were performed to investigate the efficiencies of the shell and tube-type and stack-type EGR coolers. The results show that the heat exchange of the stack-type EGR cooler is much more effective than that of the shell and tube type because of the increased surface area and better mixing of the coolant flow, and also more PM is produced at low exhaust gas temperature than at high temperature.

Calculation of mass emissions, oxygen mass fraction and thermal capacity of the inducted charge in SI and diesel engines from exhaust and intake gas analysis

New computational procedures are proposed for experimentally evaluating air–fuel ratio and mass fractions of exhaust emissions as well as EGR rate, oxygen mass fraction and thermal capacity of the inducted charge in IC engines running with diesel oil, gasoline or any alternative liquid or gaseous fuel, such as LPG or CNG. Starting from the chemical reaction of fuel with air, from gaseous and smoke level measurements in the raw gases, the procedures calculate the volume fractions of oxygen in the combustion air and of compounds in the exhaust gases, including those that are not usually measured, such as water, nitrogen and hydrogen. The methods also take the effects of various fuel and combustion air compositions into account, as well as to the presence of water vapor, CO 2, Ar and He in the combustion air. The algorithms are applied to four different automotive engines under wide ranges of steady-state operating conditions: three turbocharged diesel engines featuring high-pressure cooled EGR systems, and an SI naturally aspirated bi-fuel engine running on either gasoline or CNG. The computed air–fuel ratios are compared to those obtained from directly measured air and fuel mass-flow rates as well as from more conventional UEGO sensor data. The mass emissions are worked out in terms of both brake specific mass emissions and emission indexes of each pollutant species, and the results are compared to those obtained by applying SAE and ISO recommended practices. The computed oxygen mass fraction of the inducted charge was then compared to that derived from direct measurement of O 2 concentration in inlet manifold. Finally, the sensitivity of results to the main engine working parameters, the influence of environmental conditions (in particular the effect of air humidity on NO x formation) and the experimental uncertainties are determined.