A Study of Combustion Inefficiency in Diesel LTC and Gasoline-Diesel RCCI via Detailed Emission Measurement

2014 ◽  
Author(s):  
Shouvik Dev ◽  
Prasad Divekar ◽  
Kelvin Xie ◽  
Xiaoye Han ◽  
Xiang Chen ◽  
...  
Keyword(s):  
Diesel Fuel ◽  
Combustion Process ◽  
Speciation Analysis ◽  
Ratio Test ◽  
Emission Measurement ◽  
Exhaust Gas ◽  
Compression Ignition ◽  
Engine Operation ◽  
Incomplete Combustion ◽  
Production Of Hydrogen

Reduction of engine-out NOx emissions to ultra-low levels is facilitated by enabling low temperature combustion (LTC) strategies. However, there is a significant energy penalty in terms of combustion efficiency as evidenced by the accompanying high levels of hydrocarbon (HC), carbon monoxide (CO), and hydrogen emissions. In this work, the net fuel energy lost as a result of incomplete combustion in two different LTC regimes is studied. The first LTC strategy, partially premixed compression ignition (PPCI), is investigated using a single, high pressure, in-cylinder injection of diesel fuel along with the application of exhaust gas recirculation (EGR). The second strategy includes dual-fuel application – reactivity controlled compression ignition (RCCI) of port injected gasoline and direct injected diesel. Moderate to high levels of EGR are necessary during engine operation in either of the two LTC pathways. A detailed analysis of the incomplete combustion products was conducted while the engine was operated in the aforementioned LTC modes. Speciation analysis of hydrocarbons was performed by sampling the exhaust gas in an FTIR. The total HC and the CO emissions were simultaneously measured using an FID and an NDIR, respectively. The production of hydrogen during the combustion process was also evaluated using a mass spectrometer. Engine tests were conducted at a baseline load level of 10 bar IMEP in the PPCI and RCCI modes. Load extension tests, up to 17 bar IMEP, were then conducted in the RCCI mode by increasing the gasoline-to-diesel fuel ratio. Test results indicated that CO, H2, and light HC made up for most of the combustion in-efficiency in the PPCI mode while heavier HC and aromatics were significantly higher in the RCCI mode.

scholarly journals Research on combustion process of gasoline homogenous charge compression ignition engine

2018 ◽  
Vol 184 ◽  
pp. 01013
Author(s):  
Corneliu Cofaru ◽  
Mihaela Virginia Popescu
Keyword(s):  
Experimental Research ◽  
Fuel Injection ◽  
Combustion Process ◽  
Fuel Mixture ◽  
Spark Ignition Engine ◽  
Injection System ◽  
Compression Ignition ◽  
Compression Ignition Engine ◽  
Engine Operation ◽  
Homogenous Charge Compression Ignition

The paper presents the research designed to develop a HCCI (Homogenous Charge Compression Ignition) engine starting from a spark ignition engine platform. The chosen test engine was a single cylinder, four strokes provided with a carburettor. The results of experimental research data obtained on this version were used as a baseline for the next phase of the research. In order to obtain the HCCI configuration, the engine was modified, as follows: the compression ratio was increased from 9.7 to 11.5 to ensure that the air – fuel mixture auto-ignite and to improve the engine efficiency; the carburettor was replaced by a direct fuel injection system in order to control precisely the fuel mass per cycle taking into account the measured intake air-mass; the valves shape were modified to provide a safety engine operation by ensuring the provision of sufficient clearance beetween the valve and the piston; the exchange gas system was changed from fixed timing to variable valve timing to have the possibilities of modification of quantities of trapped burnt gases. The cylinder processes were simulated on virtual model. The experimental research works were focused on determining the parameters which control the combustion timing of HCCI engine to obtain the best energetic and ecologic parameters.

NOx Emission of Diesel Fuel Blended with Different Saturation Degrees of Biofuel and with Oxygenator

2014 ◽  
Vol 660 ◽  
pp. 397-401 ◽  
Author(s):  
Mohd Fareez Edzuan bin Abdullah ◽  
Mohd Hisyamuddin bin Sulaiman ◽  
Noor Aliah Binti Abdul Majid
Keyword(s):  
Diesel Fuel ◽  
Flue Gas ◽  
Combustion Process ◽  
Nox Emission ◽  
Dominant Factor ◽  
Compression Ignition ◽  
Nox Formation ◽  
Fuel Blends ◽  
Combustion Tests ◽  
Co Emission

This paper discusses the nitrogen oxides (NOx) emission characteristics of compression ignition diesel engine operating on diesel fuel blends with different saturation degrees of biofuel and with methanol. In order to investigate the dominant factor of increased NOx in biofuels, diesel combustion tests were conducted under idling condition and the tailpipe exhaust emissions were measured by a flue gas analyzer. The general trend where NOx emission increased and reduced carbon monoxide (CO) emission in the biofuel and methanol blend cases were observed. The NOx emission levels increased as the biofuel saturation degree decreased, where it may be suggested that the prompt NOx mechanism is significant in total NOx formation of biofuel combustion process.

Combustion Mode Switching Characteristics of a Medium-Duty Engine Operated in Compression Ignition/PCCI Combustion Modes

2018 ◽  
Vol 140 (9) ◽  
Author(s):  
Akhilendra Pratap Singh ◽  
Nikhil Bajpai ◽  
Avinash Kumar Agarwal
Keyword(s):  
Combustion Engine ◽  
Mode Switching ◽  
Exhaust Gas ◽  
Compression Ignition ◽  
Oxides Of Nitrogen ◽  
Combustion Mode ◽  
Engine Operation ◽  
Combustion Modes ◽  
Brake Mean Effective Pressure ◽  
Study Results

Premixed charge compression ignition (PCCI) combustion is a novel combustion concept, which reduces oxides of nitrogen (NOx) and particulate matter (PM) emissions simultaneously. However, PCCI combustion cannot be implemented in commercial engines due to its handicap in operating at high engine loads. This study is focused on the development of hybrid combustion engine in which engine can be operated in both combustion modes, namely, PCCI and compression ignition (CI). Up to medium loads, engine was operated in PCCI combustion and at higher loads, the engine control unit (ECU) automatically switched the engine operation to CI combustion mode. These combustion modes can be automatically switched by varying the fuel injection parameters and exhaust gas recirculation (EGR) by an open ECU. The experiments were carried out at constant engine speed (1500 rpm) and the load was varied from idling to full load (5.5 bar brake mean effective pressure (BMEP)). To investigate the emission and particulate characteristics during different combustion modes and mode switching, continuous sampling of the exhaust gas was done for a 300 s cycle, which was specifically designed for this study. Results showed that PCCI combustion resulted in significantly lower NOx and PM emissions compared to the CI combustion. Lower exhaust gas temperature (EGT) in the PCCI combustion mode resulted in slightly inferior engine performance. Slightly higher concentration of unregulated emission species such as sulfur dioxide (SO2) and formaldehyde (HCHO) in PCCI combustion mode was another important observation from this study. Lower concentration of aromatic compounds in PCCI combustion compared to CI combustion reflected relatively lower toxicity of the exhaust gas. Particulate number-size distribution showed that most particulates emitted in PCCI combustion mode were in the accumulation mode particle (AMP) size range, however, CI combustion emitted relatively smaller sized particles, which were more harmful to the human health. Overall, this study indicated that mode switching has significant potential for application of PCCI combustion mode in production grade engines for automotive sector, which would result in relatively cleaner engine exhaust compared to CI combustion mode engines.

An Experimental Investigation of the Exhaust Emissions From Spark-Assisted Homogeneous Charge Compression Ignition in a Single-Cylinder Research Engine

2009 ◽  
Author(s):  
P. E. Keros ◽  
B. T. Zigler ◽  
J. T. Wiswall ◽  
S. M. Walton ◽  
M. S. Wooldridge
Keyword(s):  
Homogeneous Charge Compression Ignition ◽  
Exhaust Emissions ◽  
Nox Emissions ◽  
Exhaust Gas ◽  
Compression Ignition ◽  
Cylinder Pressure ◽  
Engine Operation ◽  
Single Cylinder ◽  
Spark Timing ◽  
Homogeneous Charge

The present study investigates the potential impact of spark-assisted (SA) homogeneous charge compression ignition (HCCI) on pollutant exhaust gas emissions from an internal combustion engine. A single-cylinder research engine was used to compare the exhaust emissions of the engine when operated in HCCI, SA-HCCI and conventional spark ignited modes of operation. The study builds on previous results demonstrating the effects of the spark plasma kernel on the ignition process [1, 2]. Specifically, this study investigates the NOx, CO, and HC emissions from an optical engine fueled with indolene in HCCI and SA-HCCI modes at fuel lean conditions. Fuel/air equivalence ratios ranged from φ = 0.3–0.6. Time-averaged emissions were measured using an exhaust gas analyzer. In-cylinder pressure data were also acquired. The results show NOx emissions follow the trends of peak in-cylinder pressure implying that thermal NOx mechanisms dominate both the HCCI and SA-HCCI modes of engine operation. For SA-HCCI, spark timing could be used to change ignition phasing, and consequently change the in-cylinder peak pressure and resulting NOx emissions. Comparing HCCI and SA-HCCI emissions at nominally similar conditions (specifically, comparable indicated mean effective pressures and equivalence ratios) yielded similar NOx emissions. These data show that SA-HCCI may not have a NOx penalty when the spark timing is carefully applied.

Study of the Variations in Cylinder-Exhaust-Gas Temperature Over Inlet Air and Operation-Input Parameters of Compression-Ignition Engines

2014 ◽  
Vol 136 (6) ◽  
Author(s):  
Gong Chen
Keyword(s):  
Air Temperature ◽  
Thermal Loading ◽  
Exhaust Emissions ◽  
Exhaust Gas ◽  
Compression Ignition ◽  
Gas Temperature ◽  
Compression Ignition Engine ◽  
Engine Operation ◽  
Compression Ignition Engines ◽  
Exhaust Gas Temperature

Cylinder-exhaust-gas temperature (Texh) of a turbocharged compression-ignition engine indicates the levels of engine thermal loading on cylinder and exhaust components, thermal efficiency performance, and engine exhaust emissions. In consideration that Texh is affected by engine air inlet condition that primarily includes inlet air temperature (Ti) and pressure (pi), this paper studies the variation (ΔTexh) of Texh over varying the engine inlet air parameters of compression-ignition engines. The study is to understand ΔTexh with appropriate relations between the inlet parameters and Texh being identified and simply modeled. The regarded effects on Texh and ΔTexh for both naturally aspirated and turbocharged engines of this type are analyzed and predicted. The results indicate that Texh increases as Ti increases or pi decreases. The rate of variation in ΔTexh over varying Ti or pressure pi is smaller in a turbocharged engine than that in a naturally aspirated engine, as reflected from the model and results of the analysis. The results also indicate, for instance, Texh would increase approximately by ∼2 °C as Ti increases by 1 °C or increase by ∼35 °C as pi decreases by 10−2 MPa, as predicted for a typical high-power turbocharged diesel engine operating at a typical full-load condition. The design and operating parameters significant in influencing ΔTexh along with varying Ti or pi are studied in addition. These include the degree of engine cylinder compression, the level of intake manifold air temperature, the magnitude of intake air boost, and the quantity of cycle combustion thermal input. As those parameters change, the rate of variation in Texh varies. For instance, the results indicate that the rate of ΔTexh versus the inlet air parameters would increase as the quantity of cycle combustion thermal input becomes higher. With the understanding of ΔTexh, the engine output performances of thermal loading, efficiency, and exhaust emissions, concerning engine operation at variable ambient temperature or pressure, can be understood and evaluated for the purpose of engine analysis, design, and optimization.

A Study of Combustion Inefficiency in Diesel Low Temperature Combustion and Gasoline–Diesel RCCI Via Detailed Emission Measurement

2015 ◽  
Vol 137 (12) ◽  
Author(s):  
Shouvik Dev ◽  
Prasad Divekar ◽  
Kelvin Xie ◽  
Xiaoye Han ◽  
Xiang Chen ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Low Temperature ◽  
Combustion Products ◽  
Combustion Efficiency ◽  
Emission Measurement ◽  
Low Temperature Combustion ◽  
Compression Ignition ◽  
Incomplete Combustion ◽  
Temperature Combustion ◽  
Energy Penalty

Reduction of engine-out NOx emissions to ultra-low levels is facilitated by enabling low temperature combustion (LTC) strategies. However, there is a significant energy penalty in terms of combustion efficiency as evidenced by the high levels of hydrocarbon (HC), carbon monoxide (CO), and hydrogen emissions. In this work, the net fuel energy lost as a result of incomplete combustion in two different LTC regimes is studied—partially premixed compression ignition (PPCI) using in-cylinder injection of diesel fuel and reactivity controlled compression ignition (RCCI) of port injected gasoline and direct injected diesel. A detailed analysis of the incomplete combustion products was conducted. Test results indicated that carbon monoxide (CO), hydrogen, and light hydrocarbon (HC) made up for most of the combustion in-efficiency in the PPCI mode, while heavier HC and aromatics were significantly higher in the RCCI mode.

Characteristics of Particulate Emissions of Compression Ignition Engine Fueled With Biodiesel Derived From Soybean

2008 ◽  
Vol 130 (5) ◽  
Author(s):  
Myung Yoon Kim ◽  
Seung Hyun Yoon ◽  
Jin Woo Hwang ◽  
Chang Sik Lee
Keyword(s):  
Size Distribution ◽  
Diesel Fuel ◽  
Engine Speed ◽  
Biodiesel Fuel ◽  
Exhaust Gas ◽  
Compression Ignition ◽  
Compression Ignition Engine ◽  
Particulate Size ◽  
Particulate Mass ◽  
Intake Pressure

An experimental investigation was performed on the effect of engine speed, exhaust gas recirculation (EGR), and boosting intake pressure on the particulate size distribution and exhaust gas emissions in a compression ignition engine fueled with biodiesel derived from soybean. The results obtained by biodiesel fuel were compared to those obtained by petroleum diesel fuel with a sulfur content of 16.3ppm. A scanning mobility particulate sizer was used for size distribution analysis, and it measured mobility equivalent particulate diameter in the range of 10.4–392.4nm. In addition to the size distribution of the particulates, exhaust emissions, such as oxides of nitrogen (NOx), hydrocarbon, and carbon monoxide emissions, and combustion characteristics under different engine operating parameters were investigated. The engine operating parameters in terms of engine speed, EGR, and intake pressure were varied to investigate their individual impacts on the combustion and exhaust emission characteristics. As the engine speed was increased for both fuels, the larger size particulates, which dominantly contribute particulate mass, were increased; however, total numbers of particulate were reduced. Compared to diesel fuel, the combustion of biodiesel fuel reduced particulate concentration of relatively larger size where most of the particulate mass is found. Moreover, dramatically lower hydrocarbon and carbon monoxide emissions were found in the biodiesel-fueled engine. However, the NOx emission of the biodiesel-fueled diesel engine shows slightly higher concentration compared to diesel fuel at the same injection timing. EGR significantly increased the larger size particulates, which have diameter near the maximum measurable range of the instrument; however, the total number of particulates was found not to significantly increase with increasing EGR rate for both fuels. Boosting intake pressure shifted the particulate size distribution to smaller particulate diameter and effective reduction of larger size particulate was found for richer operating conditions.

A detail simulation of reactivity controlled compression ignition combustion strategy in a heavy-duty diesel engine run on natural gas/diesel fuel

2017 ◽  
Vol 19 (7) ◽  
pp. 774-789 ◽  
Author(s):  
Mojtaba Ebrahimi ◽  
Mohammad Najafi ◽  
Seyed Ali Jazayeri ◽  
Ali Reza Mohammadzadeh
Keyword(s):  
Diesel Engine ◽  
Natural Gas ◽  
Diesel Fuel ◽  
Compression Ignition ◽  
Heavy Duty ◽  
Engine Operation ◽  
Reactivity Controlled Compression Ignition ◽  
Heavy Duty Diesel Engine ◽  
Heavy Duty Diesel ◽  
Compression Ignition Combustion

The aim of this study is to investigate in details the effects of a number of combustion parameters to optimize the reactivity controlled compression ignition operation running on natural gas and diesel fuel. In the present work, a single-cylinder heavy-duty diesel engine with a specially modified bathtub piston bowl profile for reactivity controlled compression ignition operation is studied and simulated through commercial software. A broad load range from 5.6 to 13.5 bar indicated mean effective pressure at a constant engine speed of 1300 r/min, fixed amount of diesel fuel mass, and with no exhaust gas recirculation is considered. The results from the developed model confirm that the model can accurately simulate the reactivity controlled compression ignition combustion. Also, by focusing on the time of formation of certain important radicals in combustion, the start of combustion and the time of natural gas dissociation are accurately predicted. Furthermore, the influence of some parameters such as different diesel fuel injection strategies, intake temperature, and intake pressure on the reactivity controlled compression ignition combustion is evaluated and the limitation of the engine operation at low temperature combustion is investigated.

scholarly journals On the assessment of autoignition delay for Diesel fuel and Biodiesel B20

2018 ◽  
Vol 234 ◽  
pp. 03002
Author(s):  
Bogdan Radu ◽  
Alexandru Racovitza ◽  
Radu Chiriac
Keyword(s):  
Diesel Fuel ◽  
Compression Ignition ◽  
Single Cycle ◽  
Engine Operation ◽  
Compression Ignition Engines ◽  
Ci Engine ◽  
Biodiesel Fuels ◽  
Wu Method ◽  
Autoignition Delay ◽  
The Eu

The use of bio-fuels is a necessity nowadays, regulated by European legislation, which imposes to the EU-countries an increase in the substitution rate of classic fossil Diesel fuel. Biodiesel (B) fuel proves to be a reliable agent to fulfil this requirement, but a certain number of aspects have to be ameliorated regarding the compatibility of this kind of fuel with the existent compression ignition engines. One of these problems relies on the autoignition delay, on which the research results are still dispersed. The paper proposes an analysis of this autoignition delay when using a compression ignition (CI) engine fuelled with Diesel fuel and with blends of Diesel and Biodiesel fuels (B20 – 20% volumetric fraction of Biodiesel), starting from several correlations given by the literature, which are based on single-cycle analysis and application of the integral Livengood-Wu method. The obtained results offer an image of the in-cylinder processes complexity and of the B20 fuel behaviour related to the tested engine operation.

scholarly journals Effects of Two Pilot Injection on Combustion and Emissions in a PCCI Diesel Engine

Energies ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1651
Author(s):  
Deqing Mei ◽  
Qisong Yu ◽  
Zhengjun Zhang ◽  
Shan Yue ◽  
Lizhi Tu
Keyword(s):  
Diesel Engine ◽  
Combustion Process ◽  
Exhaust Gas ◽  
Pilot Injection ◽  
Compression Ignition ◽  
Ignition Timing ◽  
Turbocharged Diesel Engine ◽  
Injection Quantity ◽  
Low Load ◽  
Gas Recirculation

The effects of two pilot injections on combustion and emissions were evaluated in a single−cylinder turbocharged diesel engine, which operated in premixed charge compression ignition (PCCI) modes with multiple injections and heavy exhaust gas recirculation under the low load by experiments and simulation. It was revealed that with the delay of the start of the first pilot injection (SOI−P1) or the advance of the start of second pilot injection (SOI−P2), respectively, the pressure, heat release rate (HRR), and temperature peak were all increased. Analysis of the combustion process indicates that, during the two pilot injection periods, the ignition timing was mainly determined by the SOI−P2 while the first released heat peak was influenced by SOI−P1. With the delay of SOI−P1 or the advance of SOI−P2, nitrogen oxide (NOx) generation increased significantly while soot generation varied a little. In addition, increasing Q1 and decreasing the second pilot injection quantity (Q2) can manipulate the NOx and soot at a low level. The advance in SOI−P2 of 5 °CA couple with increasing Q1 and reducing Q2 was proposed, which can mitigate the compromise between emissions and thermal efficiency under the low load in the present PCCI mode.

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