Application of the Passive MAHLE Jet Ignition System and Synergies with Miller Cycle and Exhaust Gas Recirculation

2020 ◽  
Author(s):  
Adrian Cooper ◽  
Anthony Harrington ◽  
Michael Bassett ◽  
Simon Reader ◽  
Michael Bunce
Keyword(s):  
Exhaust Gas Recirculation ◽  
Exhaust Gas ◽  
Miller Cycle ◽  
Ignition System ◽  
Gas Recirculation

Extending Lean and Exhaust Gas Recirculation-Dilute Operating Limits of a Modern Gasoline Direct-Injection Engine Using a Low-Energy Transient Plasma Ignition System

2016 ◽  
Vol 138 (11) ◽  
Author(s):  
James Sevik ◽  
Thomas Wallner ◽  
Michael Pamminger ◽  
Riccardo Scarcelli ◽  
Dan Singleton ◽  
...  
Keyword(s):  
Direct Injection ◽  
Exhaust Gas Recirculation ◽  
Low Energy ◽  
Gasoline Direct Injection ◽  
Combustion Stability ◽  
Exhaust Gas ◽  
Ignition System ◽  
Plasma Ignition ◽  
Gas Recirculation ◽  
Transient Plasma

The efficiency improvement and emissions reduction potential of lean and exhaust gas recirculation (EGR)-dilute operation of spark-ignition gasoline engines is well understood and documented. However, dilute operation is generally limited by deteriorating combustion stability with increasing inert gas levels. The combustion stability decreases due to reduced mixture flame speeds resulting in significantly increased combustion initiation periods and burn durations. A study was designed and executed to evaluate the potential to extend lean and EGR-dilute limits using a low-energy transient plasma ignition system. The low-energy transient plasma was generated by nanosecond pulses and its performance compared to a conventional transistorized coil ignition (TCI) system operated on an automotive, gasoline direct-injection (GDI) single-cylinder research engine. The experimental assessment was focused on steady-state experiments at the part load condition of 1500 rpm 5.6 bar indicated mean effective pressure (IMEP), where dilution tolerance is particularly critical to improving efficiency and emission performance. Experimental results suggest that the energy delivery process of the low-energy transient plasma ignition system significantly improves part load dilution tolerance by reducing the early flame development period. Statistical analysis of relevant combustion metrics was performed in order to further investigate the effects of the advanced ignition system on combustion stability. Results confirm that at select operating conditions EGR tolerance and lean limit could be improved by as much as 20% (from 22.7 to 27.1% EGR) and nearly 10% (from λ = 1.55 to 1.7) with the low-energy transient plasma ignition system.

scholarly journals Miller cycle combined with exhaust gas recirculation and post–fuel injection for emissions and exhaust gas temperature control of a heavy-duty diesel engine

2019 ◽  
Vol 21 (8) ◽  
pp. 1381-1397 ◽  
Author(s):  
Wei Guan ◽  
Vinícius B Pedrozo ◽  
Hua Zhao ◽  
Zhibo Ban ◽  
Tiejian Lin
Keyword(s):  
Control Strategies ◽  
Exhaust Gas Recirculation ◽  
Exhaust Gas ◽  
Post Injection ◽  
Miller Cycle ◽  
Gas Temperature ◽  
Heavy Duty Diesel ◽  
Exhaust Gas Temperature ◽  
Gas Recirculation ◽  
Total Fluid

Miller cycle has been shown as a promising engine strategy to reduce in-cylinder nitrogen oxide (NOx) formation during the combustion process and facilitate its removal in the aftertreatment systems by increasing the exhaust gas temperature. However, the level of NOx reduction and the increase in exhaust gas temperature achieved by Miller cycle alone is limited. Therefore, research was carried out to investigate the combined use of Miller cycle with other advanced combustion control strategies in order to minimise the NOx emissions and the total cost of ownership. In this article, the effects of Miller cycle, exhaust gas recirculation, and post-injection were studied and analysed on the performance and exhaust emissions of a single cylinder heavy-duty diesel engine. A cost–benefit analysis was carried out using the corrected total fluid efficiency, which includes the estimated urea solution consumption in the NOx aftertreatment system as well as the fuel consumption. The experiments were performed at a low load of 6 bar net indicated mean effective pressure. The results showed that the application of a Miller cycle–only strategy with a retarded intake valve closing at −95 crank angle degree after top dead centre decreased NOx emissions by 21% to 6.0 g/kW h and increased exhaust gas temperature by 30% to 633 K when compared to the baseline engine operation. This was attributed to a reduction in compressed gas temperature by the lower effective compression ratio and the in-cylinder mass trapped due to the retarded intake valve closing. These improvements, however, were accompanied by a fuel-efficiency penalty of 1%. A further reduction in the level of NOx from 6.0 to 3.0 g/kW h was achieved through the addition of exhaust gas recirculation, but soot emissions were more than doubled to 0.022 g/kW h. The introduction of a post-injection was found to counteract this effect, resulting in simultaneous low NOx and soot emissions of 2.5 and 0.012 g/kW h, respectively. When taking into account the urea consumption, the combined use of Miller cycle, exhaust gas recirculation, and post-injection combustion control strategies were found to have relatively higher corrected total fluid efficiency than the baseline case. Thus, the combined ‘Miller cycle + exhaust gas recirculation + post-injection’ strategy was the most effective means of achieving simultaneous low exhaust emissions, high exhaust gas temperature, and increased corrected total fluid efficiency.

Development of a Miller cycle engine with single-stage boosting and cooled external exhaust gas recirculation

2016 ◽  
Vol 231 (6) ◽  
pp. 766-780 ◽  
Author(s):  
Yongsheng He ◽  
Jim Liu ◽  
Bin Zhu ◽  
David Sun
Keyword(s):  
Fuel Consumption ◽  
Compression Ratio ◽  
Fuel Economy ◽  
Exhaust Gas Recirculation ◽  
Operating Conditions ◽  
Single Stage ◽  
Exhaust Gas ◽  
Brake Specific Fuel Consumption ◽  
Miller Cycle ◽  
Gas Recirculation

In this paper, the development of a Miller cycle gasoline engine which has a high compression ratio from 11.5:1 to 12.5:1, single-stage turbocharging and external cooled exhaust gas recirculation is described. The improvement in the fuel economy by adding external cooled exhaust gas recirculation to the Miller cycle engine at different geometric compression ratios were experimentally evaluated in part-load operating conditions. The potential of adding external cooled exhaust gas recirculation in full-load conditions to mitigate pre-ignition in order to allow higher geometric compression ratios to be utilized was also assessed. An average of 3.2% additional improvement in the fuel economy was achieved by adding external cooled exhaust gas recirculation to the Miller cycle engine at a geometric compression ratio of 11.5:1. It was also demonstrated that the fuel consumption of the engine with external cooled exhaust gas recirculation was reduced by 3–7% in a wide range of part-load operating conditions and that the engine output of the Miller cycle engine at a geometric compression ratio of 12.5:1 increased at 2000 r/min in the full-load condition. The Miller cycle engine with external cooled exhaust gas recirculation at a geometric compression ratio of 12.5:1 achieved a broad brake specific fuel consumption range of 220 g/kW h or lower, with the lowest brake specific fuel consumption of 215 g/kW h. While there are still challenges in implementing external cooled exhaust gas recirculation, the Miller cycle engine with single-stage turbocharging and external cooled exhaust gas recirculation showed its potential for substantial improvement in the fuel economy as one of the technical pathways to meet future requirements in reducing carbon dioxide emissions.

scholarly journals Variable valve actuation–based combustion control strategies for efficiency improvement and emissions control in a heavy-duty diesel engine

2019 ◽  
Vol 21 (4) ◽  
pp. 578-591 ◽  
Author(s):  
Wei Guan ◽  
Vinícius B Pedrozo ◽  
Hua Zhao ◽  
Zhibo Ban ◽  
Tiejian Lin
Keyword(s):  
Control Strategies ◽  
Exhaust Gas Recirculation ◽  
Exhaust Gas ◽  
Effective Pressure ◽  
Miller Cycle ◽  
Variable Valve Actuation ◽  
Indicated Mean Effective Pressure ◽  
Variable Valve ◽  
Gas Recirculation ◽  
Valve Actuation

High nitrogen oxide levels of the conventional diesel engine combustion often requires the introduction of exhaust gas recirculation at high engine loads. This can adversely affect the smoke emissions and fuel conversion efficiency associated with a reduction of the in-cylinder air-fuel ratio (lambda). In addition, low exhaust gas temperatures at low engine loads reduce the effectiveness of aftertreatment systems necessary to meet stringent emissions regulations. These are some of the main issues encountered by current heady-duty diesel engines. In this work, variable valve actuation–based advanced combustion control strategies have been researched as means of improving upon the engine exhaust temperature, emissions, and efficiency. Experimental analysis was carried out on a single-cylinder heady-duty diesel engine equipped with a high-pressure common-rail fuel injection system, a high-pressure loop cooled exhaust gas recirculation, and a variable valve actuation system. The variable valve actuation system enables a late intake valve closing and a second intake valve opening during the exhaust stroke. The results showed that Miller cycle was an effective technology for exhaust temperature management of low engine load operations, increasing the exhaust gas temperature by 40 °C and 75 °C when running engine at 2.2 and 6 bar net indicated mean effective pressure, respectively. However, Miller cycle adversely effected carbon monoxide and unburned hydrocarbon emissions at a light load of 2.2 bar indicated mean effective pressure. This could be overcome when combining Miller cycle with a second intake valve opening strategy due to the formation of a relatively hotter in-cylinder charge induced by the presence of internal exhaust gas recirculation. This strategy also led to a significant reduction in soot emissions by 82% when compared with the baseline engine operation. Alternatively, the use of external exhaust gas recirculation and post injection on a Miller cycle operation decreased high nitrogen oxide emissions by 67% at a part load of 6 bar indicated mean effective pressure. This contributed to a reduction of 2.2% in the total fluid consumption, which takes into account the urea consumption in aftertreatment system. At a high engine load of 17 bar indicated mean effective pressure, a highly boosted Miller cycle strategy with exhaust gas recirculation increased the fuel conversion efficiency by 1.5% while reducing the total fluid consumption by 5.4%. The overall results demonstrated that advanced variable valve actuation–based combustion control strategies can control the exhaust gas temperature and engine-out emissions at low engine loads as well as improve upon the fuel conversion efficiency and total fluid consumption at high engine loads, potentially reducing the engine operational costs.

Sign in / Sign up

Export Citation Format

Share Document