Effects of application of variable valve timing on the exhaust gas temperature improvement in a low-loaded diesel engine

Başaran, Hasan Üstün; Özsoysal, Osman Azmi

doi:10.1016/j.applthermaleng.2017.04.098

Cited by 61 publications

(28 citation statements)

References 26 publications

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“…As illustrated on Figure 9 below, IEGR causes reduction on volumetric efficiency as well. However, the reduction is relatively low compared to aforementioned conventional airflow reduction techniques [13][14][15][16]. Thus, it can be predicted that IEGR can be more successful during transient operations compared to those methods.…”

Section: Resultsmentioning

confidence: 98%

“…Therefore, it requires fuel consumption penalty (above 5 %) to keep engine load constant [12]. In addition to EEVO, decreasing in-cylinder air induction can also increase exhaust temperatures on diesel engine systems [13][14][15][16]. Those air-flow reducing methods are highly effective, however, they cause a dramatic reduction on volumetric efficiency which can be critical during transientstate operations.…”

Section: Introductionmentioning

confidence: 99%

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Improving Exhaust Temperature Management At Low-loaded Diesel Engine Operations Via Internal Exhaust Gas Recirculation

Başaran¹

2019

deufmd

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ÖzModern karayolu otomotiv araçları sıkı emisyon yönetmeliklerini karşılamak için genellikle egzoz arıtım sistemleri (EAS) kullanmaktadırlar. Bu sistemler emisyon oranlarını azaltmada çoğu zaman etkili olsa da, düşük-yüklerde düşük egzoz sıcaklıkları (250 o C'nin altında) yüzünden etkisiz olmaktadırlar. Bu çalışma, bir dizel motor modeli üzerinde, egzoz sıcaklıklarının düşük yüklerde iç egzoz gazı devridaimi (İEGD) metoduyla 250 o C'nin üzerine çıkarılabileceğini göstermektedir. Motor sistemi 1700 devir/dakika hızda ve 2,5-4,5 bar fren ortalama efektif basınç motor yükleri arasında çalışmaktadır. İEGD silindir-içi sıcak artık egzoz gazı miktarını arttırmakta ve bu yüzden önemli bir egzoz sıcaklığı artışına (70 o C'ye kadar) sebep olmaktadır. Daha sıcak egzoz sistemi, EAS emisyon dönüşüm verimini çoğunlukla % 90'ın üstünde tutar ve arttırılan ısı transfer oranlarıyla (% 142'ye kadar) EAS katalizör yatağının daha hızlı ısınmasını sağlar. İEGD geleneksel EAS ısıtma teknikleri kadar yakıt tüketici değildir ve yakıt tüketimi artışını % 5'in altında tutabilmektedir. AbstractModern on-road automotive vehicles mostly utilize exhaust after-treatment (EAT) systems to meet the stringent emission regulations. Although those systems are generally effective to reduce emission rates, they are ineffectual at low loads due to low exhaust temperatures (below 250 o C). This study demonstrates on a diesel engine model that exhaust temperatures can be increased above 250 o C at light loads through internal exhaust gas recirculation (IEGR) method. Engine system operates at 1700 RPM engine speed and within 2.5-4.5 bar brake mean effective pressure (BMEP) engine loads. IEGR increases the amount of in-cylinder hot residual exhaust gas and thus causes a considerable exhaust temperature rise (up to 70 o C). Warmer exhaust system keeps EAT emission conversion efficiency mostly above 90 % and accelerates EAT catalyst bed warm-up through increased (up to 142 %) heat transfer rates. IEGR is not as fuel-consuming as conventional EAT warming techniques and can keep the fuel consumption rise below 5 %.

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Section: Resultsmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Improving Exhaust Temperature Management At Low-loaded Diesel Engine Operations Via Internal Exhaust Gas Recirculation

Başaran¹

2019

deufmd

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“…The model is used on a previous study by the author to demonstrate that exhaust temperatures can be increased above 250 o C at low loads through reasonable control of IVC [17]. Nominal valve timings and valve lifts on Table 1 are also taken from Ref.…”

Section: Engine Properties and Simulation Modelmentioning

confidence: 99%

“…Nominal valve timings and valve lifts on Table 1 are also taken from Ref. [17]. On this earlier work, the model is also validated with the experimental results of a similar diesel engine [38].…”

Section: Engine Properties and Simulation Modelmentioning

confidence: 99%

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Utilizing Exhaust Valve Opening Modulation for Fast Warm-up of Exhaust After-treatment Systems on Highway Diesel Vehicles

Başaran

2020

International Journal of Automotive Science and Technology

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Current on-road vehicles are generally outfitted with exhaust after-treatment (EAT) systems to meet the stringent emission regulations. At cold start and low-loaded operations, those systems need to be warmed up above a threshold temperature (generally 250oC) for effective performance. High exhaust temperatures and high exhaust flow rates are required to accelerate the EAT warm up which are mostly not available at low-loaded diesel vehicle operations. Therefore, the objective of this work is to improve EAT warm up at low loads through utilizing exhaust valve opening (EVO) modulation which allows both elevated exhaust temperatures and exhaust flow rates. A 1-D engine simulation program is used to model the system which is set to operate at 1200 RPM engine speed and at 2.5 bar brake mean effective pressure (BMEP) engine load. Exhaust temperature can be increased above 250oC via either early or late EVO timings. Reduced expansion work in advanced EVO timings and increased pumping loss in retarded EVO timings require higher fuel consumption (up to 15 % and 20 %, respectively) to keep engine load constant. Those high fuel penalties reduce engine air-to-fuel ratio and rise exhaust temperature more than 55oC. Exhaust mass flow rate is improved up to 9 % in the system as well. The method increases exhaust gas energy up to 40 % and rises heat transfer rate to the EAT system up to 140 % compared to nominal condition. The technique is highly effective at heating up EAT systems, however, it also causes high fuel inefficiency which needs to be considered.

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Engine Performance Analysis

Maurya

2019

Mechanical Engineering Series

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Effects of application of variable valve timing on the exhaust gas temperature improvement in a low-loaded diesel engine

Cited by 61 publications

References 26 publications

Improving Exhaust Temperature Management At Low-loaded Diesel Engine Operations Via Internal Exhaust Gas Recirculation

Improving Exhaust Temperature Management At Low-loaded Diesel Engine Operations Via Internal Exhaust Gas Recirculation

Utilizing Exhaust Valve Opening Modulation for Fast Warm-up of Exhaust After-treatment Systems on Highway Diesel Vehicles

Engine Performance Analysis

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