HD diesel engine – exhaust gas temperature management and advanced exhaust gas aftertreatment technology for ultra-low NOx emission legislation

Author(s):  
Jonas Edvardsson ◽  
Klaus Hadl ◽  
Eric Hein ◽  
Georg Kraus ◽  
Hannes Noll ◽  
...  
Author(s):  
Sungjun Yoon ◽  
Hongsuk Kim ◽  
Daesik Kim ◽  
Sungwook Park

Stringent emission regulations (e.g., Euro-6) force automotive manufacturers to equip DPF (diesel particulate filter) on diesel cars. Generally, post injection is used as a method to regenerate DPF. However, it is known that post injection deteriorates specific fuel consumption and causes oil dilution for some operating conditions. Thus, an injection strategy for regeneration becomes one of key technologies for diesel powertrain equipped with a DPF. This paper presents correlations between fuel injection strategy and exhaust gas temperature for DPF regeneration. Experimental apparatus consists of a single cylinder diesel engine, a DC dynamometer, an emission test bench, and an engine control system. In the present study, post injection timing covers from 40 deg aTDC to 110 deg aTDC and double post injection was considered. In addition, effects of injection pressures were investigated. The engine load was varied from low-load to mid-load and fuel amount of post injection was increased up to 10mg/stk. Oil dilution during fuel injection and combustion processes were estimated by diesel loss measured by comparing two global equivalences ratios; one is measured from Lambda sensor installed at exhaust port, the other one is estimated from intake air mass and injected fuel mass. In the present study, the differences in global equivalence ratios were mainly caused from oil dilution during post injection. The experimental results of the present study suggest an optimal engine operating conditions including fuel injection strategy to get appropriate exhaust gas temperature for DPF regeneration. Experimental results of exhaust gas temperature distributions for various engine operating conditions were summarized. In addition, it was revealed that amounts of oil dilution were reduced by splitting post injection (i.e., double post injection). Effects of injection pressure on exhaust gas temperature were dependent on combustion phasing and injection strategies.


2018 ◽  
Vol 20 (1) ◽  
pp. 141-154 ◽  
Author(s):  
P Maniatis ◽  
U Wagner ◽  
T Koch

A manipulation of the charge exchange allows controlling the amount of residual gas during engine warm-up. The residual gas during the warm-up phase leads to an increase of the exhaust gas temperature and supports to reach the exhaust after-treatment system operating temperature faster. In addition, the warm residual gas increases the combustion chamber temperature, which reduces the HC and CO emissions. However, fuel consumption increases. For that reason, such heating measures should be the best compromise of both, exhaust gas temperature increase and engine efficiency, in order to provide efficient heating strategies for passenger car diesel engines. Therefore, simulative and experimental investigations are carried out at the Institute of Internal Combustion Engines of the Karlsruhe Institute of Technology to establish a reliable cam design methodology. For the experimental investigations, a modern research single-cylinder diesel engine was set up on a test bench. In addition, a one-dimensional simulation model of the experimental setup was created in order to simulate characteristics of valve lift curves and to investigate their effects on the exhaust gas temperature and the exhaust gas enthalpy flow. These simulations were based on design of experiments (DoE), so that all characteristics can be used sustainably for modeling and explaining their influences on the engine operation. This methodology allows numerically investigating promising configurations and deriving cam contours which are manufactured for testing. To assess the potential of these individual configurations, the results obtained were compared with each other as well as with the series configuration. Results show that the combination of DoE and one-dimensional simulation for the design of camshaft contours is well suited which was also validated with experimental results. Furthermore, the potential of residual gas retention by favorable configurations with a second event already revealed in various publications could be confirmed with respect to exhaust gas temperature increase and engine efficiency.


Author(s):  
Bibhuti B. Sahoo ◽  
Niranjan Sahoo ◽  
Ujjwal K. Saha

Synthesis gas (Syngas), a mixture of hydrogen and carbon monoxide, can be manufactured from natural gas, coal, petroleum, biomass, and even from organic wastes. It can substitute fossil diesel as an alternative gaseous fuel in compression ignition engines under dual fuel operation route. Experiments were conducted in a single cylinder, constant speed and direct injection diesel engine fuelled with syngas-diesel in dual fuel mode. The engine is designed to develop a power output of 5.2 kW at its rated speed of 1500 rpm under variable loads with inducted syngas fuel having H2 to CO ratio of 1:1 by volume. Diesel fuel as a pilot was injected into the engine in the conventional manner. The diesel engine was run at varying loads of 20, 40, 60, 80 and 100%. The performance of dual fuel engine is assessed by parameters such as thermal efficiency, exhaust gas temperature, diesel replacement rate, gas flow rate, peak cylinder pressure, exhaust O2 and emissions like NOx, CO and HC. Dual fuel operation showed a decrease in brake thermal efficiency from 16.1% to a maximum of 20.92% at 80% load. The maximum diesel substitution by syngas was found 58.77% at minimum exhaust O2 availability condition of 80% engine load. The NOx level was reduced from 144 ppm to 103 ppm for syngas-diesel mode at the best efficiency point. Due to poor combustion efficiency of dual fuel operation, there were increases in CO and HC emissions throughout the range of engine test loads. The decrease in peak pressure causes the exhaust gas temperature to rise at all loads of dual fuel operation. The present investigation provides some useful indications of using syngas fuel in a diesel engine under dual fuel operation.


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