Effects of injection timing and CO2 dilution on combustion and emissions behaviors of a stoichiometric GDI engine under medium load conditions

Fuel ◽  
2021 ◽  
Vol 303 ◽  
pp. 121262
Author(s):  
Changming Gong ◽  
Xiankai Si ◽  
Fenghua Liu
Keyword(s):  
Injection Timing ◽  
Gdi Engine ◽  
Load Conditions

Investigation of Performance and Fuel Economy for Cylinder Deactivation Engine at Part Load Operation

2016 ◽  
Vol 819 ◽  
pp. 443-448 ◽  
Author(s):  
S.F. Zainal Abidin ◽  
Mohd Farid Muhamad Said ◽  
Azhar Abdul Aziz ◽  
Mohd Azman Abas ◽  
N.I. Arishad
Keyword(s):  
Fuel Economy ◽  
Fuel Injection ◽  
Injection Timing ◽  
Original Performance ◽  
Part Load ◽  
Automotive Engine ◽  
Engine Efficiency ◽  
Efficiency Performance ◽  
Valve Opening ◽  
Load Conditions

In automotive engine applications, the spark ignition (SI) engines can operate at various engine speed and load conditions. However, most of the time was spend at part load operations, where they operate below their rated output especially during cruising or idling. The needs of improvement in term of engine efficiency at part load operation become more popular among the engine manufacturers. One of the main reasons for efficiency dropped at part load conditions is the flow restrictions at the throttle valve opening area due to nearly-close position to control amount of inducted air into the cylinder, which leads to increasing in pumping losses. Hence, there are a lot of studies and investigations have been carried out to tackle these problems without sacrificing the original performance. This paper will investigate further the engine efficiency, performance as well as fuel economy by using one-dimensional (1-D) simulation tool. A baseline simulation model of a 1.6 liters four cylinders, port fuel injection engine has been developed based on the actual engine geometries. This baseline model applied predictive combustion to predict the amount of cylinder pressure based on actual ignition and injection timing on bench. The simulated results show a very good agreement with the measured data. Additionally, this study also proved that the deactivation half of the cylinders can significantly reduce the pumping losses of fired cylinder while eliminated the pumping work of unfired cylinders.

Study of low load performance on a two-stroke direct injection spark ignition aero-piston engine fuelled with diesel

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Rui Liu ◽  
Haocheng Ji ◽  
Minxiang Wei
Keyword(s):  
Fuel Consumption ◽  
Direct Injection ◽  
Spark Ignition ◽  
Injection Timing ◽  
Ignition Energy ◽  
Power Performance ◽  
Si Engine ◽  
Content Type ◽  
Low Load ◽  
Load Conditions

Purpose The purpose of this paper is to investigate power performance, economy and hydrocarbons (HC)/carbon monoxide (CO) emissions of diesel fuel on a two-stoke direct injection (DI) spark ignition (SI) engine. Design/methodology/approach Experimental study was carried out on a two-stroke SI diesel-fuelled engine with air-assisted direct injection, whose power performance and HC/CO emissions characteristics under low-load conditions were analysed according to the effects of ignition energy, ignition advance angle (IAA), injection timing angle and excess-air-ratio. Findings The results indicate that, for the throttle position of 10%, a large IAA with adequate ignition energy effectively increases the power and decrease the HC emission. The optimal injection timing angle for power and fuel consumption is 60° crank angle (CA) before top dead centre (BTDC). Lean mixture improves the power performance with the HC/CO emissions greatly reduced. At the throttle position of 20%, the optimal IAA is 30°CA BTDC. The adequate ignition energy slightly improves the power output and greatly decreases HC/CO emissions. Advancing the injection timing improves the power and fuel consumption but should not exceed the exhaust port closing timing in case of scavenging losses. Burning stoichiometric mixture achieves maximum power, whereas burning lean mixture obviously reduces the fuel consumption and the HC/CO emissions. Practical implications Gasoline has a low flash point, a high-saturated vapour pressure and relatively high volatility, and it is a potential hazard near a naked flame at room temperature, which can create significant security risks for its storage, transport and use. The authors adopt a low volatility diesel fuel for all vehicles and equipment to minimise the number of different devices using various fuels and improve the potential military application safety. Originality/value Under low-load conditions, the two stroke port-injected SI engine performance of burning heavy fuels including diesel or kerosene was shown to be worse than those of gasoline. The authors have tried to use the DI method to improve the performance of the diesel-fuelled engine in starting and low-load conditions.

The Effects of Injection Timing and Injected Fuel Mass on Local Charge Conditions and Emissions for Gasoline Direct Injection Engines

2017 ◽  
Author(s):  
Doohyun Kim ◽  
Angela Violi ◽  
André Boehman
Keyword(s):  
Combustion Chamber ◽  
Direct Injection ◽  
Gasoline Direct Injection ◽  
Injection Timing ◽  
Charge Composition ◽  
Gaseous Species ◽  
Fuel Mass ◽  
Soot Precursors ◽  
Gdi Engine ◽  
Fuel Mixing

Increased Particulate Matter (PM) emissions from Gasoline Direct Injection (GDI) engines compared to conventional Port Fuel Injection (PFI) engines have been raising concerns because of the PM’s detrimental health effects and the stringent emissions regulations. One of the widely accepted hypotheses is that local rich pockets inside the combustion chamber are the primary reason for the increased PM emissions. In this paper, we investigate the effects of injection strategies on the charge composition and local thermodynamic conditions of a light duty GDI engine, and determine their impact on PM emissions. The operation of a 1.6L GDI engine is simulated using a 3-D Computational Fluid Dynamics (CFD) code. Combustion characteristics of a 3-component gasoline surrogate (n-heptane/iso-octane/toluene) are analyzed and the effects of injection timing (300° vs 240° vs 180° BTDC) and injected fuel mass (globally stoichiometric vs fuel rich) are explored at 2000 rpm, 9.5 bar BMEP condition, focusing on the homogeneity of the charge and the formation of the gaseous species that are soot precursors. The results indicate that when the physical time for air/fuel mixing is not long enough, fuel-rich pockets are present until combustion occurs, where high concentrations of soot precursors are found, such as acetylene and pyrene. In addition, simulation results indicate that the location of wetted surface as well as the in-cylinder flow structure induced by the fuel jet hitting the piston bowl is significantly influenced by varying the injection timing, which affects subsequent air/fuel mixing. When the injected fuel mass is increased, the equivalence ratio distribution inside the combustion chamber shifts toward fuel-rich side, generating more mixtures with Φ > 1.5, where formation of acetylene and pyrene are favored.

Effect of Conical Spray and Multi-Hole Spray on Gasoline Engine Mixture Formation and Combustion Performance Based on Different Injection Strategies

2020 ◽  
Vol 143 (6) ◽  
Author(s):  
Shengli Wei ◽  
Zhiqing Yu ◽  
Zhilei Song ◽  
Fan Yang ◽  
Chengcheng Wu
Keyword(s):  
Gasoline Engine ◽  
Direct Injection ◽  
Mixture Distribution ◽  
Gasoline Direct Injection ◽  
Injection Timing ◽  
Mixture Formation ◽  
Injection Strategy ◽  
Gdi Engine ◽  
The Difference ◽  
Injection Strategies

Abstract This article presents a numerical investigation carried out to determine the effects of second and third injection timing on combustion characteristics and mixture formation of a gasoline direct injection (GDI) engine by comparing conical spray against multihole spray. The results showed that at the engine 80% full load of 2000 r/min, the difference in mixture distribution between the two sprays was obvious with double and triple injection strategies. With the second injection timing from 140 deg CA delay to 170 deg CA, the in-cylinder pressure, the in-cylinder temperature, and the heat release rate of the conical spray increased by 20.8%, 9.8%, and 30.7% and that of the multihole spray decreased by 30.7%, 13.6%, and 37.8%. The delay of the injection time reduced the performance of the engine with the multihole spray, and the performance of the multihole spray was obviously in the simulation of the triple injection strategy. However, for the conical spray, the application of the triple injection strategy increased the temperature and the pressure compared with the double injection strategy.

Assessment of the impacts of combustion chamber bowl geometry and injection timing on a reactivity controlled compression ignition engine at low and high load conditions

2020 ◽  
pp. 146808742096121
Author(s):  
Bahram Jafari ◽  
Mahdi Seddiq ◽  
Seyyed Mostafa Mirsalim
Keyword(s):  
Combustion Chamber ◽  
Fuel Consumption ◽  
High Load ◽  
Injection Timing ◽  
Compression Ignition ◽  
Compression Ignition Engine ◽  
Load Range ◽  
Reactivity Controlled Compression Ignition ◽  
Diesel Injection ◽  
Load Conditions

The present paper aims to assess the impacts of diesel injection timing and two bowl geometries including re-entrant and wide-shallow combustion chambers on the combustion characteristics, emissions formation, and fuel consumption in a reactivity controlled compression ignition diesel engine under low and high load (five and nine bar indicating mean effective pressure) conditions. The results revealed that diesel injection at −60 CA ATDC under low load conditions significantly decreased soot and NOx emissions simultaneously for both piston bowl geometries. The use of the wide-shallow chamber decreased the period of the ignition delay and increased the engine operable load range as a result of more stable combustion under high-load conditions compared to the re-entrant chamber. Moreover, at all diesel injection timings, the indicated specific fuel consumption was decreased by nearly 4.8 and 6.6% under low and high load conditions, respectively when the wide-shallow combustion chamber was used since the heat transfer loss was lower than that of the re-entrant chamber. However, NOx emission under high load conditions at the center of the combustion chamber and more soot emission in the exhaust gas are two disadvantages of the wide-shallow chamber versus the re-entrant combustion chamber.

Effects of Pre-Injection on Combustion Characteristics of a Single-Cylinder Diesel Engine

2009 ◽  
Author(s):  
M. Mittal ◽  
G. Zhu ◽  
T. Stuecken ◽  
H. J. Schock
Keyword(s):  
Diesel Engine ◽  
Combustion Process ◽  
Load Condition ◽  
Combustion Characteristics ◽  
Combustion Noise ◽  
Injection Timing ◽  
Single Cylinder ◽  
Multiple Injections ◽  
Main Injection ◽  
Load Conditions

Multiple injections used for diesel engines, especially pre- and post-injections, have the potential to reduce combustion noise and emissions with improved engine performance. This paper outlines the combustion characteristics of a single-cylinder diesel engine with multiple injections. The effects of pre-injection (multi-injection) on combustion characteristics are presented in a single-cylinder diesel engine at different engine speeds and load conditions. A common rail fuel system with a solenoid injector, driven by a peak and hold circuit, is used in this work. This enables us to control the number of injections, fuel injection timing and duration, and the fuel rail pressure that can be used to optimize the engine combustion process (e.g., eliminate engine knock). Mass fraction burned and burn durations are determined by analyzing the measured in-cylinder pressure data. Results are compared with the cases when no pre-injection was used, i.e. only main injection, at the same engine speeds and load conditions. In each study, different cases are considered with the variation in main injection timing. It is found that at full-load condition and lower engine speeds pre-injection is an effective method to alter the engine burn rate and hence to eliminate knock.

Simulation Research on the Spray and Formation of Mixture of Gasoline Direct Injection Engine

2013 ◽  
Vol 448-453 ◽  
pp. 3440-3444
Author(s):  
Bo Yu Chen ◽  
Ai Min Du ◽  
Zhi Jun Xu
Keyword(s):  
Computational Model ◽  
Cfd Simulation ◽  
Direct Injection ◽  
Simulation Software ◽  
Gasoline Direct Injection ◽  
Simulation Research ◽  
Gasoline Direct Injection Engine ◽  
Calculation Results ◽  
Gdi Engine ◽  
Load Conditions

A computational model of a GDI engine is established by 3D CFD simulation software. A simulation on the formation of mixture of the engine under 1500r/min, full load conditions are carried out. The calculation results provide a reference for the optimizing of the engine.

Study on Optimization of Control Parameters for the Second Cycle during Forward Rotation Direct-Start Process at a GDI Engine

2015 ◽  
Vol 742 ◽  
pp. 551-555
Author(s):  
Wen Xu Sun ◽  
Wei Hong ◽  
Fang Xi Xie ◽  
Yan Su
Keyword(s):  
Fuel Injection ◽  
Rotation Speed ◽  
Cooling Water ◽  
Injection Timing ◽  
Control Parameters ◽  
Ignition Timing ◽  
Cooling Water Temperature ◽  
Gdi Engine ◽  
Crankshaft Rotation ◽  
Start Process

To get better starting performance for GDI engine forward rotation direct-starting without starter, the optimized choices of fuel injection and ignition control parameters under different initial start conditions was carried out in a wall-guided GDI engine. The results showed that the ignition timing and injection timing have been less affected by the initial start conditions. When the ignition timing is kept near its compression TDC and the injection timing is kept within the scope of 2-10 °CA after the crankshaft rotation, the engine all can get higher rotation speed under different initial start conditions. When the fuel pressures and cooling water temperature are lower, the richer mixture was needed for obtaining higher rotation speed.

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