Effects of Exhaust Gas Recirculation on Knock Intensity of a Downsized Gasoline Spark Ignition Engine

2018 ◽  
Vol 141 (1) ◽  
Author(s):  
Mingzhang Pan ◽  
Haiqiao Wei ◽  
Dengquan Feng
Keyword(s):  
Compression Ratio ◽  
Fuel Injection ◽  
Maximum Amplitude ◽  
Exhaust Gas Recirculation ◽  
Spark Ignition Engine ◽  
Exhaust Gas ◽  
Engine Knock ◽  
Intake Pressure ◽  
Control Port ◽  
Gas Recirculation

Exhaust gas recirculation (EGR) has gained prominence as a significant method to control port fuel injection engine knock caused by high compression ratio and high intake pressure (IP). In this paper, the effect of EGR on knock intensity was investigated under various conditions which included different compression ratios (9:1, 10:1, 11:1), IPs (1.0 bar, 1.2 bar, 1.4 bar) and intake temperatures (ITs, 20 °C, 40 °C, 60 °C). The torque output being a crucial variant was also considered. The results showed that EGR effectively reduced the maximum amplitude of pressure oscillations (MAPO) and knock intensity factor (KI20). The effect of EGR on knock resistance was more significant at higher compression ratio, IP, and IT. The output torque of the engine reached a peak value with a suitable EGR ratio which also controlled the intensity of knock under different conditions.

scholarly journals Enhancement of combustion characteristics of VCR diesel engine by optimizing engine parameters

2021 ◽  
Vol 3 (8) ◽  
Author(s):  
Prabhakara Rao Ganji ◽  
Rajesh Khana Raju Vysyaraju ◽  
Srinivasa Rao Surapaneni ◽  
B. Karuna Kumar
Keyword(s):  
Diesel Engine ◽  
Compression Ratio ◽  
Fuel Injection ◽  
Injection Pressure ◽  
Exhaust Gas Recirculation ◽  
Exhaust Gas ◽  
Performance And Emission ◽  
Start Of Injection ◽  
Fuel Injection Pressure ◽  
Gas Recirculation

AbstractIn recent years, engine emissions have been one of the important problems which are of great concern. Hence, there is a growing need to develop engines with reduced emission. In the present study, Variable Compression Ratio diesel engine model has been validated by comparing the simulation results with the experimental. The study is aimed at analyzing the effect of compression ratio, exhaust gas recirculation, fuel injection pressure and start of injection on engine performance and emission characteristics. Using composite desirability technique, the engine parameters have been optimized to achieve lower NOx, soot and ISFC. The optimum combination has been observed at Compression ratio 17.52, Start of injection −30.1 °aTDC, Fuel injection pressure 736.06 bar and Exhaust gas recirculation 28.29%. ISFC, NOx and soot are reduced by 2.37%, 29.11% and 83.81% respectively. Higher Target Fuel Distribution Index indicates the improved mixture homogeneity for the optimized parameters.

scholarly journals Experimental study on knock sources in spark ignition engine with exhaust gas recirculation

2018 ◽  
Vol 165 ◽  
pp. 35-44 ◽  
Author(s):  
Mladen Božić ◽  
Ante Vučetić ◽  
Momir Sjerić ◽  
Darko Kozarac ◽  
Zoran Lulić
Keyword(s):  
Experimental Study ◽  
Exhaust Gas Recirculation ◽  
Spark Ignition ◽  
Spark Ignition Engine ◽  
Exhaust Gas ◽  
Gas Recirculation

Diesel Engine Intake Condition Control-Oriented Models for Active Fuel Injection Profile Control

2011 ◽  
Author(s):  
Fengjun Yan ◽  
Junmin Wang
Keyword(s):  
Diesel Engine ◽  
Diesel Engines ◽  
Fuel Injection ◽  
Combustion Process ◽  
Exhaust Gas Recirculation ◽  
High Fidelity ◽  
Exhaust Gas ◽  
Engine Model ◽  
Profile Control ◽  
Gas Recirculation

Fueling control in Diesel engines is not only of significance to the combustion process in one particular cycle, but also influences the subsequent dynamics of air-path loop and combustion events, particularly when exhaust gas recirculation (EGR) is employed. To better reveal such inherently interactive relations, this paper presents a physics-based, control-oriented model describing the dynamics of the intake conditions with fuel injection profile being its input for Diesel engines equipped with EGR and turbocharging systems. The effectiveness of this model is validated by comparing the predictive results with those produced by a high-fidelity 1-D computational GT-Power engine model.

Quantification of knock benefits from reformate and cooled exhaust gas recirculation using a Livengood–Wu approach with detailed chemical kinetics

2016 ◽  
Vol 18 (7) ◽  
pp. 717-731 ◽  
Author(s):  
David K Marsh ◽  
Alexander K Voice
Keyword(s):  
Carbon Monoxide ◽  
Compression Ratio ◽  
Exhaust Gas Recirculation ◽  
Spark Ignition ◽  
Mitigation Strategies ◽  
Exhaust Gas ◽  
Spark Ignition Engines ◽  
Volume Percent ◽  
Hydroxy Radicals ◽  
Gas Recirculation

In this work, a simple methodology was implemented to predict the onset of knock in spark-ignition engines and quantify the benefits of two practical knock mitigation strategies: cooled exhaust gas recirculation and syngas blending. Based on the results of this study, both cooled exhaust gas recirculation and the presence of syngas constituents in the end-gas substantially improved the knock-limited compression ratio of the engine. At constant load, 25% exhaust gas recirculation increased the knock-limited compression ratio from 9.0 to 10.8:1 (0.07 compression ratio per 1% exhaust gas recirculation) due to lower end-gas temperature and reactant (fuel and oxygen) concentrations. At exhaust gas recirculation rates above 43%, higher intake temperature outweighed the benefits of lower end-gas reactant concentration. At constant intake temperature, cooled exhaust gas recirculation was significantly more effective at all exhaust gas recirculation rates (0.10 compression ratio per 1% exhaust gas recirculation), and no diminishing returns or optimum was observed. Both hydrogen and carbon monoxide were also predicted to improve knock by reducing end-gas reactivity, likely through the conversion of high-reactivity hydroxy-radicals to less reactive peroxy-radicals. Hydrogen increased the knock-limited compression ratio by 1.1 per volume percent added at constant energy content. Carbon monoxide was less effective, increasing the knock-limited compression ratio by 0.38 per volume percent added. Combining 25% cooled exhaust gas recirculation with reformate produced from rich combustion at an equivalence ratio of 1.3 resulted in a predicted increase in the knock-limited compression ratio of 3.5, which agreed well with the published experimental engine data. The results show the extent to which syngas blending and cooled exhaust gas recirculation each contribute separately to knock mitigation and demonstrate that both can be effective knock mitigation strategies. Together, these solutions have the potential to increase the compression ratio and efficiency of spark-ignition engines.

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