Experimental Study of an LP EGR System on an Automotive Diesel Engine, compared to HP EGR with respect to PM and NOx Emissions and Specific Fuel Consumption

Maiboom, Alain; Tauzia, Xavier; Shah, Samiur Rahman; Hétet, Jean-François

doi:10.4271/2009-24-0138

Cited by 38 publications

(19 citation statements)

References 18 publications

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“…LP or long route EGR has recently been introduced primarily as a supplement to HP EGR to provide further reductions of NOx and PM emissions [4,5,6]. Instead of diverting exhaust gas flow from before the turbine directly to the intake manifold, LP EGR passes through the turbine and the after-treatment devices before mixing with fresh air upstream of the compressor inlet.…”

Section: Introductionmentioning

confidence: 99%

Experimental Investigation of Transient Response and Turbocharger Coupling for High and Low Pressure EGR Systems

Heuwetter¹,

Glewen²,

Foster³

et al. 2014

SAE Int. J. Engines

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The transient response of an engine with both High Pressure (HP) and Low Pressure (LP) EGR loops was compared by conducting step changes in EGR fraction at a constant engine speed and load. The HP EGR loop performance was shown to be closely linked to turbocharger performance, whereas the LP EGR loop was relatively independent of turbocharger performance and vice versa. The same experiment was repeated with the variable geometry turbine vanes completely open to reduce turbocharger action and achieve similar EGR rate changes with the HP and LP EGR loops. Under these conditions, the increased loop volume of the LP EGR loop prolonged the response of intake O2 concentration following the change in air-fuel ratio. The prolonged change of intake O2 concentration caused emissions to require more time to reach steady state as well. Strong coupling between the HP EGR loop and turbochargers was again observed using a hybrid EGR strategy. The potential benefit of the HP EGR loop's smaller volume and shorter residence time was largely negated by the simultaneous use of the larger LP EGR loop. Under these conditions, the intake charge oxygen concentration responded more quickly to actuation of the LP EGR valve than the HP EGR valve.

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Section: Introductionmentioning

confidence: 99%

Experimental Investigation of Transient Response and Turbocharger Coupling for High and Low Pressure EGR Systems

Heuwetter¹,

Glewen²,

Foster³

et al. 2014

SAE Int. J. Engines

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“…As to LP EGR loop systems are effective means of simultaneously reducing the NOx emission and fuel consumption [13]. Moreover, with LP EGR loop systems, the gas flow through the turbine is unchanged while varying the EGR rate [14]. However, if very high EGR rates are desired, it is sometimes necessary to close a backpressure valve placed in the exhaust line, which is usually referred to as exhaust throttle (ET) valve.…”

Section: Introductionmentioning

confidence: 99%

Analysis of low-pressure exhaust gases recirculation transport and control in transient operation of automotive diesel engines

Luján

Climent

Arnau

et al. 2018

Applied Thermal Engineering

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The objective of the study is to determine the behavior of the low pressure exhaust gas recirculation (LP EGR) transport phenomena in the intake manifold during engine transient operation. The investigation also analyzes the influence of the propagation of the pressure waves in the intake manifold on the engine performance. In this sense, there is a clear trade-off: long intake lines improve the engine volumetric efficiency at low engine speeds but delay the EGR transport in the system. The experiments were performed on a test bench with a 1.6 liter Euro-5 specification diesel engine. A CO2 fast tracking measurement device was setup and placed in two locations in the intake line in order to track the EGR transport in transient operation. The CO2 concentration is acquired with crank-angle resolution. Three different engine transients at constant engine speed were studied. They are extreme and worst-case scenarios in driving situations: (i) from low load to full load, (ii) from full load to low load, and (iii) from low load to medium load. In this way, it is possible to observe the behavior of the engine when: (i) leaving the EGR zone, (ii) entering into the EGR zone, and (iii) changing operating point without leaving the EGR zone. A consistent methodology that combines experimental results and a 1D model capable to predict the behavior of the engine was developed. The results obtained in this investigation show a relevant phenomenon: depending on the synchronization of the EGR and Exhaust Throttle (ET) valves, an overshoot occurs when the engine enters into EGR zone. In this study, the results show the importance of the synchronization of the valves that control the EGR strategy. Comparisons between measured and modeled CO2 concentrations lead to conclude that the EGR transport during engine transient operation is correctly predicted within a 1D engine code.

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“…Currently, EGR continues to be employed as a technique to reduce NOx. As NOx emissions become more stringent, the EGR rates increase and strategies using mixed EGR loops (high pressure and low pressure) are implemented in current engines, in some of these research works can be appreciated [1][2][3].…”

Section: Introductionmentioning

confidence: 99%

Exhaust gas recirculation dispersion analysis using in-cylinder pressure measurements in automotive diesel engines

Luján

Climent

Plá

et al. 2015

Applied Thermal Engineering

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Experimental Study of an LP EGR System on an Automotive Diesel Engine, compared to HP EGR with respect to PM and NOx Emissions and Specific Fuel Consumption

Cited by 38 publications

References 18 publications

Experimental Investigation of Transient Response and Turbocharger Coupling for High and Low Pressure EGR Systems

Experimental Investigation of Transient Response and Turbocharger Coupling for High and Low Pressure EGR Systems

Analysis of low-pressure exhaust gases recirculation transport and control in transient operation of automotive diesel engines

Exhaust gas recirculation dispersion analysis using in-cylinder pressure measurements in automotive diesel engines

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