A Study of Injection Strategy to Achieve High Load Points for Gasoline Compression Ignition (GCI) Operation

2017 ◽  
Author(s):  
Khanh Cung ◽  
Stephen Ciatti
Keyword(s):  
High Efficiency ◽  
Cetane Number ◽  
Load Condition ◽  
Low Noise ◽  
High Load ◽  
Premixed Combustion ◽  
Injection Timing ◽  
Compression Ignition ◽  
Injection Strategy ◽  
Engine Load

Many studies have shown that gasoline compression ignition (GCI) can replace conventional diesel combustion (CDC) by achieving high efficiency and low smoke and toxic gaseous emissions simultaneously. This is due to the low cetane number of gasoline that results in long ignition delay, allowing very advanced injection timing. This gives even longer time for fuel-air mixing, thus resulting in locally lean combustion that produces low particulate matter (PM). However, GCI operation faces challenges at high engine load condition. At high load conditions, large amounts of fuel injected early for premixed combustion can lead to high combustion noise from premixed combustion. Meanwhile, more fuel late injected late leads to poor mixing, hence higher smoke. Multiple injections can offer the flexibility in controlling the in-cylinder fuel stratification level. In this study, moderate to high engine loads of 8 to 14 bar BMEP were accomplished by utilizing an optimal multiple injection scheme. Injection timing of pilot, main, and post injections was investigated individually for its effect on the emission and engine performance. A moderate level of exhaust gas recirculating (EGR) was used to achieve low temperature combustion (LTC) condition. While higher EGR reduced NOx significantly due to lower combustion temperature, it affected the maximum boost that could be acquired by the turbocharger due to the reduction in exhaust enthalpy. During the engine load/speed sweep, calculations of combustion, thermodynamics, gas exchange, and mechanical efficiencies were analyzed to identify factor that needs to be improved for GCI operation. This study also demonstrates the importance of injection strategy including high injection pressure to attain high load points with low smoke and low noise.

Effect of Injection Timing on PPCI and MPCI Mode Fueled With Straight-Run Naphtha

2013 ◽  
Vol 136 (3) ◽  
Author(s):  
Hongqiang Yang ◽  
Shijin Shuai ◽  
Zhi Wang ◽  
Jianxin Wang
Keyword(s):  
Diesel Fuel ◽  
Single Injection ◽  
Operating Conditions ◽  
Premixed Combustion ◽  
Spray Combustion ◽  
Injection Timing ◽  
Soot Emission ◽  
Compression Ignition ◽  
Injection Strategy ◽  
Injection Strategies

Partially premixed compression ignition (PPCI) and multiple premixed compression ignition (MPCI) mode of straight-run naphtha have been investigated under different injection strategies. The MPCI mode is realized by the multiple premixed combustion processes in a sequence of “spray-combustion-spray-combustion” around the compression top dead center. The spray and combustion events are preferred to be completely separated, without any overlap in the temporal sequence in order to ensure the multiple-stage premixed compression ignition. The PPCI mode is well known as the “spray-spray-combustion” sequence, with the start of combustion separated from the end of injection. Straight-run naphtha with a research octane number (RON) of 58.8 is tested in a single cylinder compression ignition engine whose compression ratio is 16.7 and displacement is 0.5 l. Double and triple injection strategies are investigated as the last injection timing sweeping at 1.0 MPa IMEP and 1800 rpm conditions. The MPCI mode is achieved using the double injection strategy, but its soot emission is higher than the PPCI mode under triple injection strategy. This is mainly because of the lower RON of the straight-run naphtha and the ignition delay is too short to form an ideally premixed combustion process after the second injection of straight-run naphtha. Diesel fuel is also tested under the same operating conditions, except for employing a single injection strategy. The naphtha PPCI and MPCI mode both have lower fuel consumption and soot emission than diesel fuel single injection mode, but the THC emissions are both higher than that of diesel fuel.

Experimental investigation of diesel/gasoline dual-fuel premixed compression ignition strategies for high thermal efficiency and high load extension

2017 ◽  
Vol 232 (10) ◽  
pp. 1374-1384 ◽  
Author(s):  
Jeongwoo Lee ◽  
Sanghyun Chu ◽  
Kyoungdoug Min ◽  
Hyunsung Jung ◽  
Hyounghyoun Kim ◽  
...  
Keyword(s):  
Thermal Efficiency ◽  
Ignition Delay ◽  
Load Condition ◽  
High Load ◽  
Premixed Combustion ◽  
Dual Fuel ◽  
Compression Ignition ◽  
Lean Premixed Combustion ◽  
Diesel Injection ◽  
Low Load

In this study, two different operating strategies of gasoline and diesel dual-fuel premixed compression ignition (PCI) were investigated by using a single cylinder compression ignition engine. Verification of high thermal efficiency potential under the low load condition and the suppression of the maximum in-cylinder pressure rise rate (PRRmax) under the relatively high load condition were considered in this study. Two approaches to implement dual-fuel PCI were considered. The first approach (A-mode PCI) was an early diesel injection with very leaner overall equivalence ratio condition. In this case, a high exhaust gas recirculation (EGR) rate was not needed because lean premixed combustion promised to provide low nitrogen oxides (NOx) and particulate matter (PM) emissions. The second method (B-mode PCI) involved the use of a high EGR rate to moderate dual-fuel combustion with adjusting diesel injection timing. The first operating strategy prolonged the ignition delay via early diesel injection and lean mixture condition; in this manner, a high EGR helped to increase ignition delay. The experimental result showed that the A-mode PCI strategy promised higher gross indicated thermal efficiency (GIE) than that of the B-mode PCI. However, the B-mode PCI strategy provided a lower PRRmax than that of the first case. By applying the A-mode PCI, which was implemented by the early diesel injection with overall lean premixed combustion, a high GIE of 47.8 % could be obtained under low speed and low load condition. In addition, the dual-fuel PCI operating range could be increased using a gross indicated mean effective pressure (gIMEP) of 14 bar at 2000 r/min with a low PRRmax of 7 bar/deg (constraint 10 bar/deg) by applying the B-mode PCI strategy, which split the heat release rate (HRR) peaks to enable smooth combustion.

Comparing Cetane Number Measurement Methods

2020 ◽  
Author(s):  
Riley C. Abel ◽  
Jon Luecke ◽  
Matthew A. Ratcliff ◽  
Bradley T. Zigler
Keyword(s):  
High Pressure ◽  
Diesel Engines ◽  
Ignition Delay ◽  
High Efficiency ◽  
Performance Metrics ◽  
Fuel Injection ◽  
Cetane Number ◽  
Compression Ignition ◽  
Fuel Performance ◽  
Compression Type

Abstract Cetane number is one of the most important fuel performance metrics for mixing controlled compression-ignition “diesel” engines, quantifying a fuel’s propensity for autoignition when injected into end-of-compression-type temperature and pressure conditions. The historical default and referee method on a Cooperative Fuel Research (CFR) engine configured with indirect fuel injection and variable compression ratio is cetane number (CN) rating. A subject fuel is evaluated against primary reference fuel blends, with heptamethylnonane defining a low-reactivity endpoint of CN = 15 and hexadecane defining a high-reactivity endpoint of CN = 100. While the CN scale covers the range from zero (0) to 100, typical testing is in the range of 30 to 65 CN. Alternatively, several constant-volume combustion chamber (CVCC)-based cetane rating devices have been developed to rate fuels with an equivalent derived cetane number (DCN) or indicated cetane number (ICN). These devices measure ignition delay for fuel injected into a fixed volume of high-temperature and high-pressure air to simulate end-of-compression-type conditions. In this study, a range of novel fuel compounds are evaluated across three CVCC methods: the Ignition Quality Tester (IQT), Fuel Ignition Tester (FIT), and Advanced Fuel Ignition Delay Analyzer (AFIDA). Resulting DCNs and ICNs are compared for fuels within the normal diesel fuel range of reactivity, as well as very high (∼100) and very low DCNs/ICNs (∼5). Distinct differences between results from various devices are discussed. This is important to consider because some new, high-efficiency advanced compression-ignition (CI) engine combustion strategies operate with more kinetically controlled distributed combustion as opposed to mixing controlled diffusion flames. These advanced combustion strategies may benefit from new fuel chemistries, but current rating methods of CN, DCN, and ICN may not fully describe their performance. In addition, recent evidence suggests ignition delay in modern on-road diesel engines with high-pressure common rail fuel injection systems may no longer directly correlate to traditional CN fuel ratings. Simulated end-of-compression conditions are compared for CN, DCN, and ICN and discussed in the context of modern diesel engines to provide additional insight. Results highlight the potential need for revised and/or multiple fuel test conditions to measure fuel performance for advanced CI strategies.

scholarly journals Experimental Investigation of Performance Characteristics of Compression Ignition Engine Fuelled with Punnai Oil Methyl Ester Blended Diesel

2017 ◽  
Vol 60 (1) ◽  
pp. 23-28
Author(s):  
Mathan Raj Vijayaragavan ◽  
Ganapathy Subramanian ◽  
Lalgudi Ramachandran ◽  
Manikandaraja Gurusamy ◽  
Rahul Kumar Tiwari ◽  
...  
Keyword(s):  
Cetane Number ◽  
Load Condition ◽  
Calorific Value ◽  
Mechanical Efficiency ◽  
Performance Characteristics ◽  
Brake Specific Fuel Consumption ◽  
Compression Ignition ◽  
Compression Ignition Engine ◽  
Brake Thermal Efficiency ◽  
Full Load

Biodiesel is a renewable substitute to conventional diesel and offers cleaner performance. Thispaper deals with performance characteristics of four stroke, water cooled Compression Ignition (CI) enginefuelled with four different oils: diesel, diesel-punnai oil biodiesel 10% (B10), diesel-punnai oil biodiesel20% (B20) and diesel-punnai oil biodiesel 30% (B30). The present research, experiments were conductedto study the effect of viscosity, cetane number, flash point, calorific value and density on performancecharacteristics of diesel, Punnai oil biodiesel and its different blends (B10, B20, B30). The experimentalresults of this study showed that the diesel has 2.6% and 4.6% higher brake specific fuel consumption(BSFC) as compared to B10 and B20, respectively at full load, whereas BSFC of diesel was same as B30at higher load. Volumetric efficiency and mechanical efficiency of B10 was 1.2% and 7.5% higher ascompared to diesel at full load condition. Brake Thermal Efficiency (BTE) and indicated thermal efficiencyof B20 was 8.12% and 7% higher as compared to diesel at full load. From this study, it is concluded thatPunnai oil biodiesel could be used as a viable alternative fuel in a single cylinder, four stroke, water cooleddirect injection diesel engine.

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.

scholarly journals A Review of Early Injection Strategy in Premixed Combustion Engines

2019 ◽  
Vol 9 (18) ◽  
pp. 3737 ◽  
Author(s):  
Xingyu Liang ◽  
Zhiwei Zheng ◽  
Hongsheng Zhang ◽  
Yuesen Wang ◽  
Hanzhengnan Yu
Keyword(s):  
Diesel Engines ◽  
Alternative Fuels ◽  
Exhaust Emissions ◽  
Injection Timing ◽  
Compression Ignition ◽  
Injection Strategy ◽  
Advantages And Disadvantages ◽  
Injection Parameters ◽  
Performance And Emissions ◽  
Early Injection

Due to the increasing awareness of environmental protection, limitations on exhaust emissions of diesel engines have become increasingly stringent. This challenges diesel engine manufacturers to find a new balance between engine performance and emissions. Advanced combustion modes for diesel engines, such as homogeneous charge compression ignition (HCCI) and premixed charge compression ignition (PCCI), which can simultaneously reduce exhaust emissions and substantially improve thermal efficiency, have drawn increasing attention. In order to allow enough time to prepare the homogeneous mixture, the early injection strategy has been utilized widely in HCCI and PCCI diesel engines. This paper is aimed at providing a comprehensive review of the effects of early injection parameters on the performance and emissions of HCCI and PCCI engines fueled by both diesel and alternative fuels. Various early injection parameters, including injection pressure, injection timing, and injection angle, are discussed. In addition, the effect of the blending ratio of alternative fuels is also summarized. Every change in parameters has its own advantages and disadvantages, which are explained in detail in order to help researchers choose the best early injection parameters for HCCI and PCCI engines.

Effects of fuel injection parameters on premixed charge compression ignition combustion and emission characteristics in a medium-duty compression ignition diesel engine

2019 ◽  
pp. 146808741986701 ◽  
Author(s):  
Santiago Molina ◽  
Antonio García ◽  
Javier Monsalve-Serrano ◽  
David Villalta
Keyword(s):  
Diesel Engine ◽  
Fuel Injection ◽  
Transport Sector ◽  
Injection Timing ◽  
Compression Ignition ◽  
Injection Strategy ◽  
Low Load ◽  
Main Injection ◽  
Compression Ignition Combustion ◽  
The Impact

From the different power plants, the compression ignition diesel engines are considered the best alternative to be used in the transport sector due to its high efficiency. However, the current emission standards impose drastic reductions for the main pollutants, that is, NO x and soot, emitted by this type of engines. To accomplish with these restrictions, alternative combustion concepts as the premixed charge compression ignition are being investigated nowadays. The objective of this work is to evaluate the impact of different fuel injection strategies on the combustion performance and engine-out emissions of the premixed charge compression ignition combustion regime. For that, experimental measurements were carried out in a single-cylinder medium-duty compression ignition diesel engine at low-load operation. Different engine parameters as the injection pattern timing, main injection timing and main injection fuel quantity were sweep. The best injection strategy was determined by means of a methodology based on the evaluation of a merit function. The results suggest that the best injection strategy for the low-load premixed charge compression ignition operating condition investigated implies using a high injection pressure and a triple-injection event with a delayed main injection with almost 15% of the total fuel mass injected.

Fuel Stratification and Partially Premixed Combustion With Neat n-Butanol in a Compression Ignition Engine

2018 ◽  
Vol 140 (12) ◽  
Author(s):  
Shouvik Dev ◽  
Tongyang Gao ◽  
Xiao Yu ◽  
Mark Ives ◽  
Ming Zheng
Keyword(s):  
Fuel Injection ◽  
Direct Injection ◽  
Premixed Combustion ◽  
Injection Timing ◽  
Compression Ignition ◽  
Compression Ignition Engine ◽  
Fuel Stratification ◽  
Partially Premixed Combustion ◽  
Partially Premixed ◽  
Ci Engines

Homogeneous charge compression ignition (HCCI) has been considered as an ideal combustion mode for compression ignition (CI) engines due to its superb thermal efficiency and low emissions of nitrogen oxides (NOx) and particulate matter. However, a challenge that limits practical applications of HCCI is the lack of control over the combustion rate. Fuel stratification and partially premixed combustion (PPC) have considerably improved the control over the heat release profile with modulations of the ratio between premixed fuel and directly injected fuel, as well as injection timing for ignition initiation. It leverages the advantages of both conventional direct injection compression ignition and HCCI. In this study, neat n-butanol is employed to generate the fuel stratification and PPC in a single cylinder CI engine. A fuel such as n-butanol can provide additional benefits of even lower emissions and can potentially lead to a reduced carbon footprint and improved energy security if produced appropriately from biomass sources. Intake port fuel injection (PFI) of neat n-butanol is used for the delivery of the premixed fuel, while the direct injection (DI) of neat n-butanol is applied to generate the fuel stratification. Effects of PFI-DI fuel ratio, DI timing, and intake pressure on the combustion are studied in detail. Different conditions are identified at which clean and efficient combustion can be achieved at a baseline load of 6 bar IMEP. An extended load of 14 bar IMEP is demonstrated using stratified combustion with combustion phasing control.

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