Numerical simulation of diesel combustion with a high exhaust gas recirculation rate

Cycle-to-cycle feedback control is employed to achieve optimal combustion phasing while maintaining high levels of exhaust gas recirculation by adjusting the spark advance and the exhaust gas recirculation valve position. The control development is based on a control-oriented model that captures the effects of throttle position, exhaust gas recirculation valve position, and spark timing on the combustion phasing. Under the assumption that in-cylinder pressure information is available, an adaptive extended Kalman filter approach is used to estimate the exhaust gas recirculation rate into the intake manifold based on combustion phasing measurements. The estimation algorithm is adaptive since the cycle-to-cycle combustion variability (output covariance) is not known a priori and changes with operating conditions. A linear quadratic regulator controller is designed to maintain optimal combustion phasing while maximizing exhaust gas recirculation levels during load transients coming from throttle tip-in and tip-out commands from the driver. During throttle tip-outs, however, a combination of a high exhaust gas recirculation rate and an overly advanced spark, product of the dynamic response of the system, generates a sequence of misfire events. In this work, an explicit reference governor is used as an add-on scheme to the closed-loop system in order to avoid the violation of the misfire limit. The reference governor is enhanced with model-free learning which enables it to avoid misfires after a learning phase. Experimental results are reported which illustrate the potential of the proposed control strategy for achieving an optimal combustion process during highly diluted conditions for improving fuel efficiency.

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In-cylinder stratification of external exhaust gas recirculation for controlling diesel combustion

International Journal of Engine Research ◽

10.1243/14680874jer04809 ◽

2009 ◽

Vol 11 (1) ◽

pp. 1-15 ◽

Cited By ~ 12

Author(s):

T Fuyuto ◽

M Nagata ◽

Y Hotta ◽

K Inagaki ◽

K Nakakita ◽

...

Keyword(s):

Exhaust Gas Recirculation ◽

Exhaust Gas ◽

Diesel Combustion ◽

Gas Recirculation

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Effect of bioethanol–diesel blends, exhaust gas recirculation rate and injection timing on performance, emission and combustion characteristics of a common rail diesel engine

Biofuels ◽

10.1080/17597269.2017.1329493 ◽

2017 ◽

Vol 10 (4) ◽

pp. 511-523

Author(s):

Venkatesh T. Lamani ◽

Aditya U. Baliga M ◽

Ajay Kumar Yadav ◽

G. N. Kumar

Keyword(s):

Diesel Engine ◽

Exhaust Gas Recirculation ◽

Combustion Characteristics ◽

Common Rail ◽

Injection Timing ◽

Exhaust Gas ◽

Recirculation Rate ◽

Gas Recirculation

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Effect of Air-Fuel Mixture Homogenisation and Exhaust Gas Recirculation on Formation of Nitrogen Oxides and Soot in a Diesel Combustion Chamber

Herald of the Bauman Moscow State Technical University Series Mechanical Engineering ◽

10.18698/0236-3941-2018-2-44-61 ◽

2018 ◽

Author(s):

Р.З. Кавтарадзе ◽

◽

Э.В. Бахрамов ◽

Keyword(s):

Nitrogen Oxides ◽

Combustion Chamber ◽

Fuel Mixture ◽

Exhaust Gas Recirculation ◽

Exhaust Gas ◽

Diesel Combustion ◽

Gas Recirculation

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Effect of balance valve on an asymmetric twin-scroll turbine for heavy-duty diesel engine

International Journal of Engine Research ◽

10.1177/1468087420930162 ◽

2020 ◽

pp. 146808742093016

Author(s):

Jianjiao Jin ◽

Jianfeng Pan ◽

Zhigang Lu ◽

Qingrui Wu ◽

Lizhong Xu

Keyword(s):

Fuel Economy ◽

High Speed ◽

Engine Speed ◽

Flow Parameter ◽

Engine Performance ◽

Exhaust Gas Recirculation ◽

Exhaust Gas ◽

Engine Fuel ◽

Recirculation Rate ◽

Gas Recirculation

A conventional asymmetric twin-scroll turbine with wastegate is capable of effectively tackling down the contradiction between fuel economy degradation and low nitrogen oxide emissions. However, as the engine speed has been rising at middle- and high-speed ranges, the pressure of small scroll inlet will be increasingly higher as compared with the intake pressure, thereby worsening fuel economy. In this study, a novel turbocharging technology of asymmetric twin-scroll turbine with a balance valve was first analyzed to more effectively balance the engine fuel economy and emission. The experiments on turbine test rig and engine performance were performed to explore the effects of balance valve on turbine performance, asymmetric ratio, exhaust gas recirculation rate, as well as engine performance. As the balance valve open degree was elevated, the turbine flow parameter was being extended, while the turbine efficiency was enhanced. Moreover, a lower asymmetric ratio could lead to a broader flow parameter range between that of partial admission and equal admission, thereby resulting in a broader regulating range of exhaust gas recirculation rate. In contrast with the asymmetric twin-scroll turbine with wastegate, the turbine running efficiency of asymmetric twin-scroll turbine with balance valve was enhanced by nearly 2%–11% at middle and high engine speed ranges, while the fuel economy was improved by nearly 1.5%–8%.

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In-cylinder studies of the effects of CO2 in exhaust gas recirculation on diesel combustion and emissions

Proceedings of the Institution of Mechanical Engineers Part D Journal of Automobile Engineering ◽

10.1243/0954407001527727 ◽

2000 ◽

Vol 214 (4) ◽

pp. 405-419 ◽

Cited By ~ 18

Author(s):

H Zhao ◽

J Hu ◽

N Ladommatos

Keyword(s):

High Speed ◽

Measurement Techniques ◽

Dilution Effect ◽

Exhaust Gas Recirculation ◽

Exhaust Emission ◽

Exhaust Gas ◽

Diesel Combustion ◽

Combustion Chambers ◽

Emission Analysis ◽

Gas Recirculation

This paper reports the results of the effects of CO2 in exhaust gas recirculation (EGR) on diesel combustion and emissions. The experiments were carried out on a specially designed single-cylinder diesel engine. In-cylinder measurements were obtained from the optically accessible swirl chamber using high-speed shadowgraphy, the two-colour method and laser extinction. Furthermore, in-cylinder pressure measurements from the combustion chambers were used to derive the heat release rates during combustion. Two experiments were carried out on the effects of CO2 on diesel combustion and pollutant formation. In the first series of experiments, CO2 was used to replace some of the oxygen in the intake mixture, which simulated the dilution effect of conventional EGR. This so-called replacement EGR method was characterized by the typical NOx and smoke trade-off, where NOx reduction was accomplished at the expense of exhaust smoke. In the second series of tests, CO2 was added to the intake charge so that the oxygen concentration in the combustion chamber was not affected. In this additional EGR method, CO2 was found to suppress both NOx and smoke emissions. The mechanisms of these two different EGR modes on diesel combustion and emissions were examined using the above in-cylinder measurement techniques and exhaust emission analysis.

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