The Effects of the Compression Ratio, Equivalence Ratio, and Intake Air Temperature on Ignition Timing in an HCCI Engine Using DME Fuel

2005 ◽  
Author(s):  
Keisuke Hamada ◽  
Shun Niijima ◽  
Kazunori Yoshida ◽  
Koji Yoshida ◽  
Hideo Shoji ◽  
...  
Keyword(s):  
Air Temperature ◽  
Compression Ratio ◽  
Equivalence Ratio ◽  
Ignition Timing ◽  
Hcci Engine

Simulation of HCCI Combustion Characteristics for Low RON Gasoline Surrogate Fuels

2014 ◽  
Vol 694 ◽  
pp. 54-58
Author(s):  
Ling Zhe Zhang ◽  
Ya Kun Sun ◽  
Su Li ◽  
Qing Ping Zheng
Keyword(s):  
Equivalence Ratio ◽  
Chemical Kinetic ◽  
Combustion Characteristics ◽  
Material Strength ◽  
Inlet Temperature ◽  
Compression Ignition Engine ◽  
Chemical Kinetic Model ◽  
Hcci Engine ◽  
Surrogate Fuels ◽  
Inlet Conditions

A reduced chemical kinetic model (103species and 468 reactions) for new low-RON(research octane number) gasoline surrogate fuels has been proposed. Simulations explored for ignition delay time have been compared with experimental data in shock tubes at pressure of 10atm-55 atm and temperatue of 600-1400 K (fuel/air equivalence ratio=0.5,1.0,2.0 and EGR rate=0, 20%). The simulation data presented 15% enlargement compared with experiments showed applicability of the new kinetic mode in this work. A combustion simulation model has been build for HCCI(homogeneous charge compression ignition) engine with Chemkin-pro. The effects of different air inlet temperature, inlet pressure, engine speed and the fuel air equivalence ratio on the combustion characteristics of the fuel were researched. The results indicated the combustion in an HCCI engine worked sufficiently with lean mixtures and low speed. Meanwhile the material strength could be influenced when the inlet conditions changed. This helps to promote the low-RON gasoline surrogate fuel application in the HCCI engine.

Residual-effected homogeneous charge compression ignition at a low compression ratio using exhaust reinduction

2003 ◽  
Vol 4 (3) ◽  
pp. 163-177 ◽  
Author(s):  
P. A. Caton ◽  
A. J. Simon ◽  
J. C. Gerdes ◽  
C. F. Edwards
Keyword(s):  
Compression Ratio ◽  
Equivalence Ratio ◽  
Homogeneous Charge Compression Ignition ◽  
Compression Ignition ◽  
Single Digit ◽  
Hcci Combustion ◽  
Actuation System ◽  
Order Of Magnitude ◽  
No Emissions ◽  
Homogeneous Charge

Studies have been conducted to assess the performance of homogeneous charge compression ignition (HCCI) combustion initiated by exhaust reinduction from the previous engine cycle. Reinduction is achieved using a fully flexible electrohydraulic variable-valve actuation system. In this way, HCCI is implemented at low compression ratio without throttling the intake or exhaust, and without preheating the intake charge. By using late exhaust valve closing and late intake valve opening strategies, steady HCCI combustion was achieved over a range of engine conditions. By varying the timing of both valve events, control can be exerted over both work output (load) and combustion phasing. In comparison with throttled spark ignition (SI) operation on the same engine, HCCI achieved 25–55 per cent of the peak SI indicated work, and did so at uniformly higher thermal efficiency. This was accompanied by a two order of magnitude reduction in NO emissions. In fact, single-digit (ppm) NO emissions were realized under many load conditions. In contrast, hydrocarbon emissions proved to be significantly higher in HCCI combustion under almost all conditions. Varying the equivalence ratio showed a wider equivalence ratio tolerance at low loads for HCCI.

Pressure Sensitivity of HCCI Auto-Ignition Temperature for Oxygenated Reference Fuels

2012 ◽  
Author(s):  
Ida Truedsson ◽  
Martin Tuner ◽  
Bengt Johansson ◽  
William Cannella
Keyword(s):  
Compression Ratio ◽  
Ignition Temperature ◽  
Equivalence Ratio ◽  
Engine Speed ◽  
Pressure Sensitivity ◽  
Hcci Combustion ◽  
Air Temperatures ◽  
Auto Ignition ◽  
Temperature Heat ◽  
Pressure Trace

The current research focuses on creating an HCCI fuel index suitable for comparing different fuels for HCCI operation. One way to characterize a fuel is to use the Auto-Ignition Temperature (AIT). The AIT can be extracted from the pressure trace. Another potentially interesting parameter is the amount of Low Temperature Heat Release (LTHR) that is closely connected to the ignition properties of the fuel. The purpose of this study was to map the AIT and amount of LTHR of different oxygenated reference fuels in HCCI combustion at different cylinder pressures. Blends of n-heptane, iso-octane and ethanol were tested in a CFR engine with variable compression ratio. Five different inlet air temperatures ranging from 50°C to 150°C were used to achieve different cylinder pressures and the compression ratio was changed accordingly to keep a constant combustion phasing, CA50, of 3±1° after TDC. The experiments were carried out in lean operation with a constant equivalence ratio of 0.33 and with a constant engine speed of 600 rpm. The amount of ethanol needed to suppress LTHR from different PRFs was evaluated. The AIT and the amount of LTHR for different combinations of n-heptane, iso-octane and ethanol were charted.

Characterizing the cyclic variability of ignition timing in a homogeneous charge compression ignition engine fuelled with n-heptane/iso-octane blend fuels

2008 ◽  
Vol 9 (5) ◽  
pp. 361-397 ◽  
Author(s):  
M Shahbakhti ◽  
C R Koch
Keyword(s):  
Equivalence Ratio ◽  
Homogeneous Charge Compression Ignition ◽  
Coolant Temperature ◽  
Cyclic Variation ◽  
Compression Ignition ◽  
Ignition Timing ◽  
Compression Ignition Engine ◽  
Hcci Combustion ◽  
Cyclic Variations ◽  
Homogeneous Charge

The cyclic variations of homogeneous charge compression ignition (HCCI) ignition timing is studied for a range of charge properties by varying the equivalence ratio, intake temperature, intake pressure, exhaust gas recirculation (EGR) rate, engine speed, and coolant temperature. Characterization of cyclic variations of ignition timing in HCCI at over 430 operating points on two single-cylinder engines for five different blends of primary reference fuel (PRF), (iso-octane and n-heptane) is performed. Three distinct patterns of cyclic variation for the start of combustion (SOC), combustion peak pressure ( Pmax), and indicated mean effective pressure (i.m.e.p.) are observed. These patterns are normal cyclic variations, periodic cyclic variations, and cyclic variations with weak/misfired ignitions. Results also show that the position of SOC plays an important role in cyclic variations of HCCI combustion with less variation observed when SOC occurs immediately after top dead centre (TDC). Higher levels of cyclic variations are observed in the main (second) stage of HCCI combustion compared with that of the first stage for the PRF fuels studied. The sensitivity of SOC to different charge properties varies. Cyclic variation of SOC increases with an increase in the EGR rate, but it decreases with an increase in equivalence ratio, intake temperature, and coolant temperature.

scholarly journals Compression Ratio Influence on Maximum Load of a Natural Gas Fueled HCCI Engine

2002 ◽  
Author(s):  
Jan-Ola Olsson ◽  
Per Tunestål ◽  
Bengt Johansson ◽  
Scott Fiveland ◽  
Rey Agama ◽  
...  
Keyword(s):  
Natural Gas ◽  
Compression Ratio ◽  
Maximum Load ◽  
Hcci Engine ◽  
Gas Fueled

Effect of Ethanol-Air Equivalence Ratio on Performance of an Endoreversible Otto Engine

2011 ◽  
Vol 110-116 ◽  
pp. 273-277
Author(s):  
Rahim Ebrahim ◽  
Mahmoud Reza Tadayon ◽  
Farshad Tahmasebi Gandomkari ◽  
Kamyar Mahbobian
Keyword(s):  
Performance Evaluation ◽  
Compression Ratio ◽  
Power Output ◽  
Thermal Efficiency ◽  
Equivalence Ratio ◽  
Maximum Power ◽  
Otto Cycle ◽  
World Community ◽  
Maximum Power Output ◽  
The World

Today, the world community is looking for fuel efficient and environmentally viable alternatives for many of the traditional energy conversion approaches. This development has further worked to increase the technical focus on conventional cycles for making them more optimum in terms of performance. Hence, the objective of this paper is to study the effect of ethanol-air equivalence ratio on the power output and the indicated thermal efficiency of an air standard Otto cycle. Optimization of the cycle has been performed for power output as well as for thermal efficiency with respect to compression ratio. The results show that the maximum power output, the optimal compression ratio corresponding to maximum power output point, the optimal compression ratio corresponding to maximum thermal efficiency point and the working range of the cycle first increase and then decrease as the equivalence ratio increases. The result obtained herein provides a guide to the performance evaluation and improvement for practical Otto engines.

The Development of Combustion Strategy in Improving the Performances of SI-PFI Engine Using E50 of Gasoline-Bioethanol Fuel Blend

2021 ◽  
pp. 115-135
Author(s):  
M. Paloboran ◽  
H. Syam ◽  
M. Yahya ◽  
Darmawang
Keyword(s):  
Linear Programming ◽  
Compression Ratio ◽  
Engine Speed ◽  
Standard Condition ◽  
Spark Ignition Engine ◽  
Ignition Timing ◽  
Fuel Blend ◽  
Non Linear Programming ◽  
Non Linear ◽  
Bioethanol Fuel

This research aims to improve the combustion performance of gasoline-bioethanol fuel blended in the ratio of 50:50 (E50) on the spark-ignition engine by employing a new combustion strategy. The Box Behnken Design of Response Surface Methodology and Non-Linear Programming was employed to optimize the performance of the engine and create some engine parameters. The performance of the engine consists of power, torque, thermal efficiency, fuel consumption, and the emission of CO and HC, while the engine and combustion parameters are compression ratio, ignition timing, and engine speed. A new combustion strategy will be applied in this study with a tiered mapping process for each engine parameter based on the MBT. The brake torque increased by 13.5 % while HC and CO emissions decreased by 15 % and 71 % respectively when the combustion strategy applied if compared o the pure gasoline in engine standard condition. Furthermore, the BSFC increased by 33 % while BTE decreased by 15 % towards the gasoline fuel. The non-linear programming applied in this study intended to figure out the best combination of the engine parameters in obtaining optimum engine performances. In the RSM analysis, the codes --1, 0, 1 represented 12, 12.5, and 13 of compression ratio, 16, 20, and 24 BTDC of ignition timing and 2000, 5000, and 8000 rpm of engine speed. Therefore, 20 BTDC of ignition timing and 13:1 of compression ratio is the optimum engine parameters used in gaining the optimal performance of the engine when E50 runs in SI-PFI engine of 150 cm3

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