Experimental Comparison of GCI and Diesel Combustion in a Medium-Duty Opposed-Piston Engine

2018 ◽  
Author(s):  
Reed Hanson ◽  
Ashwin Salvi ◽  
Fabien Redon ◽  
Gerhard Regner
Keyword(s):  
Thermal Efficiency ◽  
Combustion Efficiency ◽  
Experimental Comparison ◽  
Diesel Combustion ◽  
Compression Ignition ◽  
Piston Engine ◽  
Load Range ◽  
Combustion Performance ◽  
Poppet Valve

The Achates Power Inc. (API) Opposed Piston (OP) Engine architecture provides fundamental advantages that increase thermal efficiency over current poppet valve 4 stroke engines. In this paper, combustion performance of diesel and gasoline compression ignition (GCI) combustion in a medium duty, OP engine are shown. By using GCI, NOx and/or soot reductions can be seen compared to diesel combustion at similar or increased thermal efficiencies. The results also show that high combustion efficiency can be achieved with GCI combustion with acceptable noise and stability over the same load range as diesel combustion in an OP engine.

Experimental Comparison of Gasoline Compression Ignition and Diesel Combustion in a Medium-Duty Opposed-Piston Engine

2019 ◽  
Vol 141 (12) ◽  
Author(s):  
Reed Hanson ◽  
Ashwin Salvi ◽  
Fabien Redon ◽  
Gerhard Regner
Keyword(s):  
Thermal Efficiency ◽  
Combustion Efficiency ◽  
Experimental Comparison ◽  
Diesel Combustion ◽  
Compression Ignition ◽  
Piston Engine ◽  
Load Range ◽  
Combustion Performance ◽  
Poppet Valve

The Achates Power Inc. (API) opposed-piston (OP) engine architecture provides fundamental advantages that increase thermal efficiency over current poppet valve 4 stroke engines. In this paper, the combustion performance of diesel and gasoline compression ignition (GCI) combustion in a medium-duty, OP engine are shown. By using GCI, NOx and/or soot reductions can be seen compared with diesel combustion at similar or increased thermal efficiencies. The results also show that high combustion efficiency can be achieved with GCI combustion with acceptable noise and stability over the same load range as diesel combustion in an OP engine.

Effects of Heat Release Mode on Emissions and Efficiencies of a Compound Diesel Homogeneous Charge Compression Ignition Combustion Engine

2005 ◽  
Vol 128 (2) ◽  
pp. 446-454 ◽  
Author(s):  
Wanhua Su ◽  
Xiaoyu Zhang ◽  
Tiejian Lin ◽  
Yiqiang Pei ◽  
Hua Zhao
Keyword(s):  
Heat Release ◽  
Thermal Efficiency ◽  
Homogeneous Charge Compression Ignition ◽  
Experimental Comparison ◽  
Injection Timing ◽  
Compression Ignition ◽  
Multiple Injection ◽  
Hcci Combustion ◽  
Flexible Mode ◽  
Homogeneous Charge

A compound diesel homogeneous charge compression ignition (HCCI) combustion system has been developed based on the combined combustion strategies of multiple injection strategy and a mixing enhanced combustion chamber design. In this work, a STAR-CD based, multidimensional modeling is conducted to understand and optimize the multiple injection processes. The parameters explored included injection timing, dwell time, and pulse width. Insight generated from this study provides guidelines on designing the multipulse injection rate pattern for optimization of fuel-air mixing. Various heat release modes created by different injection strategies are investigated by experimental comparison of combustion efficiency, heat loss, and thermal efficiency. It is demonstrated that the process of fuel evaporation and mixing are strongly influenced by pulse injection parameters. Through control of the parameters, the stratification and autoignition of the premixed mixture, and the heat release mode can be controlled. The dispersed mode of heat release created only by the compound diesel HCCI combustion is a flexible mode in combustion control. The thermal efficiency with this mode can reach approximately to as high as that of conventional diesel combustion, while the NOx and smoke emissions can be reduced simultaneously and remarkably.

A study on premixed charge compression ignition combustion of natural gas with direct injection

2005 ◽  
Vol 6 (5) ◽  
pp. 443-451 ◽  
Author(s):  
T Ishiyama ◽  
H Kawanabe ◽  
K Ohashi ◽  
M Shioji ◽  
S Nakai
Keyword(s):  
Natural Gas ◽  
Fuel Injection ◽  
Direct Injection ◽  
Pressure Rise ◽  
Combustion Efficiency ◽  
Compression Ignition ◽  
Load Range ◽  
Injection Angle ◽  
Nozzle Orifice ◽  
Rich Mixture

In order to extend the available load range and obtain higher thermal efficiency in natural gas premixed charge compression ignition (PCCI) engines, a strategy for controlling direct injection combustion is discussed. Experimental results from single-cylinder engine tests demonstrate the possibility to extend load range by direct fuel injection. Reduced nozzle orifice size and reduced injection angle provide higher combustion efficiency; however, this promotes the tendency to knock because of the formation of a locally rich mixture. Arising from discussions based on prediction by computational fluid dynamics (CFD) code, considering mixture heterogeneity, it is suggested that controlling probability density functions (PDFs) of fuel concentration could be a means to control the rate of pressure rise. Restricted air utilization is useful to activate combustion at low overall equivalence ratios; on the other hand, full utilization of in-cylinder air and formation of a quantity of lean mixture can provide mild combustion.

Split Injection Strategies for Biodiesel-Fueled Premixed Charge Compression Ignition Combustion Engine—Part I: Combustion, Performance, and Emission Studies

2020 ◽  
Vol 142 (12) ◽  
Author(s):  
Akhilendra Pratap Singh ◽  
Avinash Kumar Agarwal
Keyword(s):  
Fuel Injection ◽  
Combustion Engine ◽  
Injection Pressure ◽  
Pilot Injection ◽  
Compression Ignition ◽  
Load Range ◽  
Performance And Emission ◽  
Combustion Performance ◽  
Combustion Modes ◽  
Injection Strategies

Abstract In this study, a single-cylinder research engine was used to investigate the comparative combustion, performance, and emissions characteristics of the engine in a premixed charge compression ignition (PCCI) mode combustion vis-a-vis baseline compression ignition (CI) mode combustion using three test fuels, namely, B20 (20% v/v biodiesel blended with mineral diesel), B40 (40% v/v biodiesel blended with mineral diesel), and mineral diesel. For both combustion modes, experiments were performed at constant fuel injection pressure (FIP, 700 bar), engine speed (1500 rpm), and fuel energy input (0.7 kg/h diesel equivalent). PCCI mode combustion experiments were performed at four different start of main injection (SoMI) timings using two different pilot fuel injection strategies, namely, single pilot injection (SPI, 35 deg before top dead center (bTDC)) and double pilot injection (DPI, 35 deg, and 45 deg bTDC). Results showed that advancing SoMI timing for both CI and PCCI combustion modes resulted in knocking; however, the DPI strategy resulted in relatively lesser knocking compared with the SPI strategy. The performance of PCCI mode combustion was relatively inferior compared with baseline CI mode combustion; however, biodiesel blends slightly improved the performance of PCCI mode combustion. Overall, this study shows that the PCCI mode combustion operating load range can be improved by using the DPI strategy.

Potential of reactivity-controlled compression ignition with reverse reactivity stratification (R-RCCI) fueled with gasoline and polyoxymethylene dimethyl ethers (PODEn)

2021 ◽  
pp. 146808742110136
Author(s):  
Huiquan Duan ◽  
Ming Jia ◽  
Jinpeng Bai ◽  
Yaopeng Li
Keyword(s):  
Thermal Efficiency ◽  
Volume Fraction ◽  
Pressure Rise ◽  
Combustion Efficiency ◽  
High Reactivity ◽  
Combustion Stability ◽  
Compression Ignition ◽  
Reactivity Controlled Compression Ignition ◽  
Trade Off ◽  
Polyoxymethylene Dimethyl Ethers

To improve the trade-off between thermal efficiency and peak heat release rate (HRR) of partially premixed combustion (PPC) and the combustion efficiency of reactivity-controlled compression ignition (RCCI), the combustion mode with premixed high-reactivity fuel and direct-injection (DI) low-reactivity fuel, called RCCI with reverse reactivity stratification (R-RCCI), was explored at low loads in a light-duty diesel engine in this study. Compared with diesel, polyoxymethylene dimethyl ethers (PODEn) has better volatility, which is beneficial for the formation of premixed charge, so it was used as the premixed high-reactivity fuel for R-RCCI in this work. The gasoline and P20G80 (PODEn/gasoline blends with the volume fraction of 20%/80%) were respectively applied as the DI low-reactivity fuel. By investigating the combustion characteristics of R-RCCI, it is found that R-RCCI can break the trade-off between combustion efficiency and nitrogen oxides (NOx) emissions. This is because the combustion efficiency of R-RCCI is dominated by the spray location of the DI fuel rather than the 50% burn point (CA50). As the start of injection (SOI) timing is retarded, the fuel injected within the piston bowl increases, and combustion efficiency, as well as indicated thermal efficiency (ITE), is considerably promoted. Meanwhile, CA50 progressively retards with delayed SOI timing, which effectively reduces NOx emissions. The soot emissions of R-RCCI are also extremely low. The maximum ITE of PODEn/P20G80 R-RCCI is significantly higher than that of PODEn/gasoline R-RCCI. This occurs because the higher reactivity of P20G80 can reduce the sensitivity of CA50 to SOI timing and improve combustion stability, so a more delayed SOI timing is allowed to improve ITE. With the same engine configurations, R-RCCI can reduce peak pressure rise rate and improve combustion stability, while enhancing combustion efficiency and ITE compared with RCCI at the low-load conditions tested in this study.

scholarly journals The use of partial fuel stratification to enable stable ultra-lean deflagration-based Spark-Ignition engine operation with controlled end-gas autoignition of gasoline and E85

2019 ◽  
Vol 21 (9) ◽  
pp. 1678-1695
Author(s):  
Zongjie Hu ◽  
Junjie Zhang ◽  
Magnus Sjöberg ◽  
Wei Zeng
Keyword(s):  
Thermal Efficiency ◽  
Direct Injection ◽  
Spark Ignition ◽  
Combustion Efficiency ◽  
Spark Ignition Engine ◽  
Load Range ◽  
Engine Operation ◽  
Lean Mixture ◽  
Stable Combustion ◽  
Fuel Stratification

Lean operation of Spark-Ignition engines can provide higher thermal efficiency compared to standard stoichiometric operation. However, for a homogeneous lean mixture, the associated reduction of flame speeds becomes an important issue from the perspective of robust ignition and fast flame spread throughout the charge. This study is focused on the use of a lean partial fuel stratification strategy that can stabilize the deflagration, while sufficiently fast combustion is ensured via the use of end-gas autoignition. The engine has a spray-guided Direct-Injection Spark-Ignition combustion system and was fueled with either a high-octane certification gasoline or E85. Partial fuel stratification was achieved using several fuel injections during the intake stroke in combination with a small pilot-injection concurrent with the Spark-Ignition. The results reveal that partial fuel stratification enables very stable combustion, offering higher thermal efficiency for parts of the load range in comparison to well-mixed lean and stoichiometric combustion. The heat release and flame imaging demonstrate that the combustion often has three distinct stages. The combustion of the pilot-injected fuel, ignited by the normal spark, acts as a “super igniter,” ensuring a very repeatable initiation of combustion, and flame incandescence reveals locally rich conditions. The second stage is mainly composed of blue flame propagation in a well-mixed lean mixture. The third stage is the compression autoignition of a well-mixed and typically very lean end-gas. The end-gas autoignition is critical for achieving high combustion efficiency, high thermal efficiency, and stable combustion. Partial fuel stratification enables very effective combustion-phasing control, which is critical for controlling the occurrence and intensity of end-gas autoignition. Comparing the gasoline and E85 fuels, it is noted that achieving end-gas autoignition for the higher octane E85 requires a more aggressive compression of the end-gas via the use of a more advanced combustion phasing or higher intake-air temperature.

Engine performance and emission characteristics of a compression ignition engine fuelled with diesel/dimethoxymethane blends

2005 ◽  
Vol 219 (7) ◽  
pp. 905-914 ◽  
Author(s):  
Y Ren ◽  
Z H Huang ◽  
D M Jiang ◽  
L X Liu ◽  
K Zeng ◽  
...  
Keyword(s):  
Thermal Efficiency ◽  
Mass Fraction ◽  
Volume Fraction ◽  
Engine Performance ◽  
Compression Ignition ◽  
Compression Ignition Engine ◽  
Performance And Emission ◽  
Fuel Blends ◽  
Performance And Emissions ◽  
Combustion Phase

The performance and emissions of a compression ignition engine fuelled with diesel/dimethoxymethane (DMM) blends were studied. The results showed that the engine's thermal efficiency increased and the diesel equivalent brake specific fuel consumption (b.s.f.c.) decreased as the oxygen mass fraction (or DMM mass fraction) of the diesel/DMM blends increased. This change in the diesel/DMM blends was caused by an increased fraction of the premixed combustion phase, an oxygen enrichment, and an improvement in the diffusive combustion phase. A remarkable reduction in the exhaust CO and smoke can be achieved when operating on the diesel/DMM blend. Flat NO x/smoke and thermal efficiency/smoke curves are presented when operating on the diesel/DMM fuel blends, and a simultaneous reduction in both NO x and smoke can be realized at large DMM addition. Thermal efficiency and NO x give the highest value at 2 per cent oxygen mass fraction (or 5 per cent DMM volume fraction) for the combustion of diesel/DMM blends.

Study of High Load Operation Limit Expansion for Gasoline Compression Ignition Engines

2006 ◽  
Vol 128 (2) ◽  
pp. 377-387 ◽  
Author(s):  
Koudai Yoshizawa ◽  
Atsushi Teraji ◽  
Hiroshi Miyakubo ◽  
Koichi Yamaguchi ◽  
Tomonori Urushihara
Keyword(s):  
Fuel Injection ◽  
Control Method ◽  
Combustion Process ◽  
High Load ◽  
Compression Ignition ◽  
Ignition Timing ◽  
Timing Control ◽  
Load Range ◽  
Compression Ignition Engines ◽  
Spark Plug

In this research, combustion characteristics of gasoline compression ignition engines have been analyzed numerically and experimentally with the aim of expanding the high load operation limit. The mechanism limiting high load operation under homogeneous charge compression ignition (HCCI) combustion was clarified. It was confirmed that retarding the combustion timing from top dead center (TDC) is an effective way to prevent knocking. However, with retarded combustion, combustion timing is substantially influenced by cycle-to-cycle variation of in-cylinder conditions. Therefore, an ignition timing control method is required to achieve stable retarded combustion. Using numerical analysis, it was found that ignition timing control could be achieved by creating a fuel-rich zone at the center of the cylinder. The fuel-rich zone works as an ignition source to ignite the surrounding fuel-lean zone. In this way, combustion consists of two separate auto-ignitions and is thus called two-step combustion. In the simulation, the high load operation limit was expanded using two-step combustion. An engine system identical to a direct-injection gasoline (DIG) engine was then used to validate two-step combustion experimentally. An air-fuel distribution was created by splitting fuel injection into first and second injections. The spark plug was used to ignite the first combustion. This combustion process might better be called spark-ignited compression ignition combustion (SI-CI combustion). Using the spark plug, stable two-step combustion was achieved, thereby validating a means of expanding the operation limit of gasoline compression ignition engines toward a higher load range.

A comparative numerical study of the combustion performance of the syngas-fueled HCCI engine using a toroidal piston, square bowl piston, and flat piston shape at different loads

2021 ◽  
pp. 1-27
Author(s):  
Kabbir Ali ◽  
Changup Kim ◽  
Yonggyu Lee ◽  
Seungmook Oh ◽  
Ki-Seong Kim
Keyword(s):  
Numerical Study ◽  
Pressure Rise ◽  
Fuel Mixture ◽  
Combustion Efficiency ◽  
Maximum Pressure ◽  
Cross Sectional ◽  
Combustion Performance ◽  
Hcci Engine ◽  
Heat Loss Rate ◽  
Piston Bowl

Abstract This study analyzes the combustion performance of a syngas-fueled homogenous charge compression ignition (HCCI) engine using a toroidal piston, square bowl, and flat piston shape, at low, medium, and high loads, with a constant compression ratio of 17.1. In this study, the square bowl shape is optimized by reducing the piston bowl depth and squish area ratio (squish area/cylinder cross-sectional area) from (34 to 20, 10, and 2.5) %, and compared with the flat piston shape and toroidal piston shape. This HCCI engine operates under an overly lean air–fuel mixture condition for power plant usage. ANSYS Forte CFD with GRI Mech3.0 chemical kinetics is used for combustion analysis, and the calculated results are validated by the experimental results. All simulations are accomplished at maximum brake torque (MBT) by altering the air–fuel mixture temperature at IVC with a constant equivalence ratio of 0.27. This study reveals that the main factors that affect the start of combustion , maximum pressure rise rate (MPRR), combustion efficiency, and thermal efficiency by changing the piston shape are the squish flow and reverse squish flow effects. Therefore, the square bowl piston D is the optimized piston shape that offers low MPRR and high combustion performance for the syngas-fueled HCCI engine, due to the weak squish flow and low heat loss rate through the combustion chamber wall, respectively, compared to the other piston shapes of square bowl piston A, B, and C, flat piston, and toroidal (baseline) piston shape.

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