Numerical Investigation of the Effects of Port Water Injection Timing on Performance and Emissions in a Gasoline Direct Injection Engine

2020 ◽  
Author(s):  
Peng Yin ◽  
Xuesong Li ◽  
David Hung ◽  
Yadong Fan ◽  
Min Xu
Keyword(s):  
Numerical Investigation ◽  
Direct Injection ◽  
Water Injection ◽  
Gasoline Direct Injection ◽  
Injection Timing ◽  
Direct Injection Engine ◽  
Gasoline Direct Injection Engine ◽  
Performance And Emissions

Experimental Investigation of Water Injection Technique in Gasoline Direct Injection Engine

2017 ◽  
Author(s):  
Niranjan Miganakallu ◽  
Jeffrey D. Naber ◽  
Sandesh Rao ◽  
William Atkinson ◽  
Sam Barros
Keyword(s):  
Thermal Efficiency ◽  
Direct Injection ◽  
Water Injection ◽  
Load Condition ◽  
Gasoline Direct Injection ◽  
Injection Technique ◽  
Direct Injection Engine ◽  
Effect Of Water ◽  
Gasoline Direct Injection Engine ◽  
Combustion Knock

This paper experimentally investigates the effect of water injection in the intake manifold on a naturally aspirated, single cylinder, Gasoline Direct Injection engine to determine the combustion and emissions performance with combustion knock mitigation. The endeavor of the current study is to use water injection to attain the optimum combustion phasing without knocking. Further elevated intake air temperature tests were conducted to observe the effect of water injection with respect to combustion and emissions. Experiments were carried out at medium load condition (800 kPa NIMEP, 1500 RPM) at intake air temperatures between 30–90° C in 20° C increments. Two fuels, an 87 AKI and a 93 AKI were used in this study. Baseline tests were undertaken with the high-octane fuel (93 AKI) to achieve optimal combustion phasing corresponding to Maximum Brake Torque (MBT) without water injection. Water injection was utilized for the low octane fuel to achieve combustion phasing of 8–10° ATDC and within the controlled knock limit. Combustion phasing was achieved by controlling the ignition timing, water injection quantity and timing to the knock threshold. The results showed that water injection and the resultant charge cooling mitigates combustion knock and an optimum combustion phasing based on indicated fuel conversion efficiency is achieved with a water to fuel ratio of 0.6. Water injection reduces the NOx emissions while achieving better indicated thermal efficiency compared to the baseline tests. A detailed comparison is presented on the combustion phasing, indicated thermal efficiency, burn durations, HC, NOx and PN emissions in this paper.

Analysis of the relationship between particle number and fuel cutoff in a single-cylinder gasoline direct injection engine

2020 ◽  
Vol 234 (13) ◽  
pp. 3001-3010
Author(s):  
Jingeun Song ◽  
Mingi Choi
Keyword(s):  
Particle Number ◽  
Direct Injection ◽  
Gasoline Direct Injection ◽  
Injection Timing ◽  
Cylinder Pressure ◽  
Engine Load ◽  
Direct Injection Engine ◽  
Single Cylinder ◽  
Gasoline Direct Injection Engine ◽  
Load Change

This study investigates the effects of fuel cutoff on particle number in a single-cylinder wall-guided gasoline direct injection engine. Various durations of fuel cutoff and change in load and engine stop were tested, and the in-cylinder pressure, particle number, and NO x emissions were measured. The change in in-cylinder temperature during combustion stop was calculated using the in-cylinder pressure and the ideal gas law. Experimental results showed that as the fuel cutoff duration increased, the particle number increased significantly when combustion resumed. For the injection timing before top dead center 330°, the particle number, which was 600 × 103 #/cm3 under the continuous combustion condition, increased to 6700 × 103 #/cm3 after 30 s of fuel cutoff. Both the fuel cutoff and engine stop showed enormous amount of particle number when combustion restarted. A major factor that increased particle number was the temperature reduction of piston during the combustion stop. The peak in-cylinder temperature decreased by 38 K during 30 s of motoring, which was induced by the temperature drop of the piston. Therefore, in terms of particulate emissions, it is more advantageous to lower the engine load than to stop combustion: the piston surface remains hot during load reduction. In addition, it is recommended to change the engine load slowly to reduce the particle number emissions. In this study, the rapid load change from indicated mean effective pressure of 0.25 to 0.55 MPa showed 7% higher particle number emissions than the gentle load change. On the contrary, NO x was reduced because none was generated during combustion stop. However, the fuel cutoff would increase NO x in gasoline vehicles because the oxygen in the unburned air would significantly reduce the conversion efficiency of a three-way catalytic converter. It is especially worth investigating the reason for the increase in emissions because it is easy to think that all kinds of emissions will be reduced if fuel is not burned.

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