Exhaust Heating System Performance for Boosting SCR Low Temperature Efficiency

Culbertson, David; Khair, Magdi; Zha, Yuhui; Diestelmeier, Jeff

doi:10.4271/2018-01-1428

Cited by 9 publications

(2 citation statements)

References 10 publications

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“…In the FTP cycle cold start experiment, it takes the 18 kW electric heaters 188 s to raise the temperature in the middle of the SCR to 200 • C. For 12 kW heaters, the SCR can reach the same temperature after 289 s. However, during this time, the engine's exhaust temperature is only about 120 • C. The electric heating produces favorable operating conditions that allow the SCR to quickly reach the light-off temperature and perform the purifying function. To heat a two-stage SCR on a 6.7 L Cummins diesel engine platform, Culbertson D. et al [39] use a DC heater. An urban bus running cycle characterized by lower loads, slower engine speeds, and exhaust temperatures below 170 • C is selected for the experiment.…”

Section: Application To Diesel Vehiclesmentioning

confidence: 99%

Applications of Electric Heating Technology in Vehicle Exhaust Pollution Control

Li,

Xiao,

Wang

et al. 2024

Processes

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Motor vehicle exhaust is an important cause of atmospheric pollution. Nowadays, mainstream exhaust emission aftertreatment technologies, such as TWC, DOC, SCR, and DPF, usually require sufficient temperature to perform good purification or maintain normal working conditions. Compared with exhaust gas heating technologies such as engine enrichment and fuel injection, electric heating technology can quickly increase the temperature of exhaust gas aftertreatment devices without adverse effects on engine operating conditions. This article introduces the research and progress of electric heating technology combined with traditional aftertreatment devices on major types of vehicles, such as gasoline vehicles, diesel vehicles, motorcycles, and hybrid vehicles, to improve exhaust purification efficiency and its accompanying fuel consumption impact. In addition, the common structure and characteristics of electric heaters, as well as the current status and development trend of electric heating unit technologies such as electric heating power supply are introduced.

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Section: Application To Diesel Vehiclesmentioning

confidence: 99%

Applications of Electric Heating Technology in Vehicle Exhaust Pollution Control

Li,

Xiao,

Wang

et al. 2024

Processes

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“…However, during inner-city transport, vehicles mostly operate at low loads due to the traffic congestion or the need to work on a stop-and-go schedule (such as public buses or goods distribution vehicles). Exhaust temperatures at those cases mostly fall below 250 o C [18][19][20] which is inadequate to keep TWC systems at effective levels. Therefore, particularly at light loads, there is a continuing search to improve diesel exhaust temperatures [21].…”

Section: Introductionmentioning

confidence: 99%

Effects of Intake Valve Lift Form Modulation on Exhaust Temperature and Fuel Economy of a Low-loaded Automotive Diesel Engine

Başaran

2021

International Journal of Automotive Science and Technology

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Exhaust after-treatment (EAT) systems on automotive vehicles cannot perform effectively at low loads due to low exhaust temperatures (Texhaust < 250 o C). Conventional late intake valve closure (LIVC) technique -a proven method to improve diesel exhaust temperatures -generally requires the modulation of the whole valve lift profile. However, an alternative method -boot-shaped LIVC -only needs partial lift form modulation and can rise exhaust temperatures significantly. Therefore, this study attempts to demonstrate that boot-shaped LIVC can be an alternative solution to improve exhaust temperatures above 250 o C at low-loaded operations of automotive vehicles.A 1-D engine simulation program is used to model the diesel engine system operating at 1200 RPM engine speed and at 2.5 bar brake mean effective pressure (BMEP) engine load. Boot-shaped LIVC is achieved via keeping the valve lift constant (at 4.0 mm) for a while during closure and then closing it at different closure angles. The method results in up to 55 o C exhaust temperature rise through reduced in-cylinder airflow and thus, is adequate to keep EAT system above 250 o C at low loads. The longer the boot is kept during closure, the lower the air-to-fuel ratio is reduced and the higher the exhaust temperature flows at turbine exit. Similar to conventional LIVC, boot-shaped LIVC improves fuel consumption as pumping losses are decreased in the system. Despite aforementioned improvements, EAT warm-up is affected negatively due to the significant drop-off on exhaust mass flow rates. The need to modify only some parts of the lift profile is a technical advantage and can reduce production costs.

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