Implementation Challenges and Solutions for Homogenous Charge Compression Ignition Combustion in Diesel Engines

2014 ◽  
Author(s):  
Usman Asad ◽  
Ming Zheng ◽  
David Ting ◽  
Jimi Tjong
Keyword(s):  
High Pressure ◽  
Diesel Engines ◽  
Performance Metrics ◽  
Pressure Rise ◽  
Engine Performance ◽  
Injection Pressure ◽  
Combustion Stability ◽  
Compression Ignition ◽  
Hcci Combustion ◽  
Homogenous Charge Compression Ignition

Homogenous charge compression ignition (HCCI) combustion in diesel engines can provide for cleaner operation with ultra-low NOx and soot emissions. While HCCI combustion has generated significant attention in the last decade, however, to date, it has seen very limited application in production diesel engines. HCCI combustion is typically characterized by earlier than top-dead-center (pre-TDC) phasing, very high pressure rise rates, short combustion durations and minimal control over the timing of the combustion event. To offset the high reactivity of the diesel fuel, large amounts of EGR (30 to 60%) are usually applied to postpone the initiation of combustion, shift the combustion towards TDC and alleviate to some extent, the high pressure rise rates and the reduced energy efficiency. In this work, a detailed analysis of HCCI combustion has been carried out on a high-compression ratio, single-cylinder diesel engine. The effects of intake boost, EGR quantity/temperature, engine speed, injection scheduling and injection pressure on the operability limits have been empirically determined and correlated with the combustion stability, emissions and performance metrics. The empirical investigation is extended to assess the suitability of common alternate fuels (n-butanol, gasoline and ethanol) for HCCI combustion. On the basis of the analysis, the significant challenges affecting the real-world application of HCCI are identified, their effects on the engine performance quantified and possible solutions to overcome these challenges explored through both theoretical and empirical investigations. This paper intends to provide a comprehensive summary of the implementation issues affecting HCCI combustion in diesel engines.

Implementation Challenges and Solutions for Homogeneous Charge Compression Ignition Combustion in Diesel Engines

2015 ◽  
Vol 137 (10) ◽  
Author(s):  
Usman Asad ◽  
Ming Zheng ◽  
David S.-K. Ting ◽  
Jimi Tjong
Keyword(s):  
High Pressure ◽  
Diesel Engines ◽  
Homogeneous Charge Compression Ignition ◽  
Performance Metrics ◽  
Pressure Rise ◽  
Injection Pressure ◽  
Combustion Stability ◽  
Compression Ignition ◽  
Hcci Combustion ◽  
Homogeneous Charge

Homogeneous charge compression ignition (HCCI) combustion in diesel engines can provide cleaner operation with ultralow NOx and soot emissions. While HCCI combustion has generated significant attention in the last decade, however, till date, it has seen very limited application in production diesel engines. HCCI combustion is typically characterized by earlier than top-dead-center (pre-TDC) phasing, very high-pressure rise rates, short combustion durations, and minimal control over the timing of the combustion event. To offset the high reactivity of the diesel fuel, large amounts of exhaust gas recirculation (EGR) (30–60%) are usually applied to postpone the initiation of combustion, shift the combustion toward TDC, and alleviate to some extent, the high-pressure rise rates and the reduced energy efficiency. In this work, a detailed analysis of HCCI combustion has been carried out on a high-compression ratio (CR), single-cylinder diesel engine. The effects of intake boost, EGR quantity/temperature, engine speed, injection scheduling, and injection pressure on the operability limits have been empirically determined and correlated with the combustion stability, emissions, and performance metrics. The empirical investigation is extended to assess the suitability of common alternate fuels (n-butanol, gasoline, and ethanol) for HCCI combustion. On the basis of the analysis, the significant challenges affecting the real-world application of HCCI are identified, their effects on the engine performance quantified, and possible solutions to overcome these challenges explored through both theoretical and empirical investigations. This paper intends to provide a comprehensive summary of the implementation issues affecting HCCI combustion in diesel engines.

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.

An Experimental Research on the Effects of Negative Valve Overlap on Performance and Operating Range in a Homogeneous Charge Compression Ignition Engine With RON40 and RON60 Fuels

2020 ◽  
Vol 142 (5) ◽  
Author(s):  
Seyfi Polat ◽  
Hamit Solmaz ◽  
Ahmet Uyumaz ◽  
Alper Calam ◽  
Emre Yılmaz ◽  
...  
Keyword(s):  
Pressure Rise ◽  
Engine Performance ◽  
Maximum Pressure ◽  
Compression Ignition ◽  
Compression Ignition Engine ◽  
Operating Range ◽  
Hcci Combustion ◽  
Residual Gas ◽  
Negative Valve Overlap ◽  
Valve Overlap

Abstract In this study, the effects of negative valve overlap (NVO) on homogenous charge compression ignition (HCCI) combustion and engine performance were experimentally investigated. A four stroke, single cylinder, port injection HCCI engine was operated at −16 deg crank angle (CA), −8 deg CA, and +8 deg CA valve overlap values and different lambda values and engine speeds at wide open throttle. RON40 and RON60 were used as test fuels in view of combustion and performance characteristics in HCCI mode. The variations of indicated mean effective pressure (IMEP), residual gas, CA50, indicated thermal efficiency (ITE), indicated specific fuel consumption (ISFC), maximum pressure rise rate (MPRR) and ringing intensity (RI) were observed on HCCI combustion. The results showed that NVO caused to trap residual gases in the combustion chamber. Hot residual gases showed heating and dilution effect on HCCI combustion. Combustion was retarded with the presence of residual gas at −16 deg CA NVO. Test results showed that higher imep and maximum in-cylinder pressure were obtained with RON60 according to RON40. As expected, CA50 was obtained later with RON60 compared to RON40 due to more resistance of auto-ignition. RON60 residual gas prevented the rapid and sudden combustion due to higher heat capacity of charge mixture. RI decreased with the usage of RON60 compared to RON40. Significant decrease was seen on RI with RON60 especially at lower lambda values. It was seen that HCCI combustion can be controlled with NVO and operating range of HCCI engines can be extended.

INITIAL RESULTS ON A NEW LIGHT-DUTY 2.7L OPPOSED-PISTON GASOLINE COMPRESSION IGNITION MULTI-CYLINDER ENGINE

2022 ◽  
pp. 1-8
Author(s):  
Ashwin Salvi ◽  
Reed Hanson ◽  
Rodrigo Zermeno ◽  
Gerhard Regner ◽  
Mark Sellnau ◽  
...  
Keyword(s):  
Pressure Rise ◽  
Cost Effective ◽  
Combustion Noise ◽  
Combustion Stability ◽  
Residual Fraction ◽  
Compression Ignition ◽  
Light Duty ◽  
Peak Cylinder Pressure ◽  
Near Term ◽  
Initial Results

Abstract Gasoline compression ignition (GCI) is a cost-effective approach to achieving diesel-like efficiencies with low emissions. The fundamental architecture of the two-stroke Achates Power Opposed-Piston Engine (OP Engine) enables GCI by decoupling piston motion from cylinder scavenging, allowing for flexible and independent control of cylinder residual fraction and temperature leading to improved low load combustion. In addition, the high peak cylinder pressure and noise challenges at high-load operation are mitigated by the lower BMEP operation and faster heat release for the same pressure rise rate of the OP Engine. These advantages further solidify the performance benefits of the OP Engine and emonstrate the near-term feasibility of advanced combustion technologies, enabled by the opposed-piston architecture. This paper presents initial results from a steady state testing on a brand new 2.7L OP GCI multi-cylinder engine designed for light-duty truck applications. Successful GCI operation calls for high compression ratio, leading to higher combustion stability at low-loads, higher efficiencies, and lower cycle HC+NOX emissions. Initial results show a cycle average brake thermal efficiency of 31.7%, which is already greater than 11% conventional engines, after only ten weeks of testing. Emissions results suggest that Tier 3 Bin 160 levels can be achieved using a traditional diesel after-treatment system. Combustion noise was well controlled at or below the USCAR limits. In addition, initial results on catalyst light-off mode with GCI are also presented.

scholarly journals Tailoring Charge Reactivity Using In-Cylinder Generated Reformate for Gasoline Compression Ignition Strategies

2016 ◽  
Author(s):  
Isaac W. Ekoto ◽  
Benjamin M. Wolk ◽  
William F. Northrop ◽  
Nils Hansen ◽  
Kai Moshammer
Keyword(s):  
Performance Metrics ◽  
Engine Performance ◽  
Combustion Stability ◽  
Gas Temperature ◽  
Exhaust Temperature ◽  
Start Of Injection ◽  
Main Period ◽  
Piston Crevice ◽  
Ignition Characteristics ◽  
Negative Valve Overlap

In-cylinder reforming of injected fuel during an auxiliary negative valve overlap (NVO) period can be used to optimize main-cycle combustion phasing for low-load Low-Temperature Gasoline Combustion, where highly dilute mixtures can lead to poor combustion stability. The objective of this work is to examine the effects of reformate composition on main-cycle engine performance for a research gasoline. A custom alternate-fire sequence with nine pre-conditioning cycles was used to generate a common exhaust temperature and composition boundary condition for a cycle-of-interest. Performance metrics such as main-period combustion stability and total cycle efficiency were collected for these custom cycles. The NVO-produced reformate stream was also separately collected using a dump valve apparatus and characterized in detail using both gas chromatography and photoionization mass spectroscopy. To facilitate gas sample analysis, sampling experiments were conducted using a five-component gasoline surrogate (iso-octane, n-heptane, ethanol, 1-hexene, and toluene) that matched the molecular composition, 50% boiling point, and ignition characteristics of the research gasoline. For the gasoline, it was found that the most advanced NVO start-of-injection (SOI) led to the most advanced main-cycle 10% burn angle. The effect was more pronounced as the fraction of total fuel injected in the NVO period increased. With the most retarded NVO SOI, shorter residence times and piston spray impingement limited the opportunity for injected fuel decomposition. For the gasoline surrogate, the most advanced NVO SOI had reduced reactivity relative to more intermediate NVO SOI, which was attributed to rapid in-cylinder mixing that led to a large amount of fuel quench in the piston crevice. For all NVO periods, combustion phasing advanced as the main-period fueling decreased. Slower kinetics for leaner mixtures were offset by a combination of increased bulk-gas temperature from higher charge specific heat ratios and increased fuel reactivity due to higher charge reformate fractions.

Initial Results on a New Light-Duty 2.7L Opposed-Piston Gasoline Compression Ignition Multi-Cylinder Engine

2018 ◽  
Author(s):  
Ashwin Salvi ◽  
Reed Hanson ◽  
Rodrigo Zermeno ◽  
Gerhard Regner ◽  
Mark Sellnau ◽  
...  
Keyword(s):  
Pressure Rise ◽  
High Load ◽  
Combustion Stability ◽  
Residual Fraction ◽  
Compression Ignition ◽  
Cylinder Pressure ◽  
Peak Cylinder Pressure ◽  
Low Load ◽  
Initial Results ◽  
Load Conditions

Gasoline compression ignition (GCI) is a cost-effective approach to achieving diesel-like efficiencies with low emissions. Traditional challenges with GCI arise at low-load conditions due to low charge temperatures causing combustion instability and at high-load conditions due to peak cylinder pressure and noise limitations. The fundamental architecture of the two-stroke Achates Power Opposed-Piston Engine (OP Engine) enables GCI by decoupling piston motion from cylinder scavenging, allowing for flexible and independent control of cylinder residual fraction and temperature leading to improved low load combustion. In addition, the high peak cylinder pressure and noise challenges at high-load operation are mitigated by the lower BMEP operation and faster heat release for the same pressure rise rate of the OP Engine. These advantages further solidify the performance benefits of the OP Engine and demonstrate the near-term feasibility of advanced combustion technologies, enabled by the opposed-piston architecture. This paper presents initial results from a steady state testing on a brand new 2.7L OP GCI multi-cylinder engine. A part of the recipe for successful GCI operation calls for high compression ratio, leading to higher combustion stability at low-loads, higher efficiencies, and lower cycle HC+NOx emissions. In addition, initial results on catalyst light-off mode with GCI are also presented. The OP Engine’s architectural advantages enable faster and earlier catalyst light-off while producing low emissions, which further improves cycle emissions and fuel consumption over conventional engines.

Parametric Study of Ignition and Combustion Characteristics From a Gasoline Compression Ignition Engine Using Two Different Reactivity Fuels

2016 ◽  
Author(s):  
Khanh Cung ◽  
Toby Rockstroh ◽  
Stephen Ciatti ◽  
William Cannella ◽  
S. Scott Goldsborough
Keyword(s):  
High Speed ◽  
Injection Pressure ◽  
Operating Conditions ◽  
Combustion Stability ◽  
Injection Timing ◽  
Strong Impact ◽  
Boost Pressure ◽  
Compression Ignition ◽  
Compression Ignition Engine ◽  
Ignition And Combustion

Unlike homogeneous charge compression ignition (HCCI) that has the complexity in controlling the start of combustion event, partially premixed combustion (PPC) provides the flexibility of defining the ignition timing and combustion phasing with respect to the time of injection. In PPC, the stratification of the charge can be influenced by a variety of methods such as number of injections (single or multiple injections), injection pressure, injection timing (early to near TDC injection), intake boost pressure, or combination of several factors. The current study investigates the effect of these factors when testing two gasoline-like fuels of different reactivity (defined by Research Octane Number or RON) in a 1.9-L inline 4-cylinder diesel engine. From the collection of engine data, a full factorial analysis was created in order to identify the factors that most influence the outcomes such as the location of ignition, combustion phasing, combustion stability, and emissions. Furthermore, the interaction effect of combinations of two factors or more was discussed with the implication of fuel reactivity under current operating conditions. The analysis was done at both low (1000 RPM) and high speed (2000 RPM). It was found that the boost pressure and air/fuel ratio have strong impact on ignition and combustion phasing. Finally, injection-timing sweeps were conducted whereby the ignition (CA10) of the two fuels with significantly different reactivity were matched by controlling the boost pressure while maintaining a constant lambda (air/fuel equivalence ratio).

Performance of Homogenous Charge Compression Ignition (HCCI) Engine With Premixed Methane/Air Supported by DME for Electrical Power Generation Application

2006 ◽  
Author(s):  
Mojtaba Keshavarz ◽  
Seyed Ali Jazayeri
Keyword(s):  
Electrical Power ◽  
Engine Performance ◽  
Compression Ignition ◽  
Power Cycle ◽  
Auto Ignition ◽  
Hcci Engines ◽  
Ic Engines ◽  
Working Region ◽  
Homogenous Charge Compression Ignition ◽  
Operation Cycle

Homogenous Charge Compression Ignition (HCCI) is a mode of combustion in IC engines in which premixed fuel and air is ignited spontaneously. There is a belief that there is a great potential to improve fuel consumption and reduce NOx emissions using HCCI. In this study, a single zone, zero dimensional, thermo-kinetic model has been developed and a computer program with MATLAB software is used to predict engine performance characteristics. This model has been used to predict the principal parameters of controlling auto-ignition to acceptable level and this work leads to achieving the working region with two limitations for knock and misfire. The cycle is simulated with premixed blend of methane and DME with air. To highlight the importance of using HCCI engines instead of conventional diesel engines, an ISO continuous operation cycle (COP) and prime power cycle (PRP) has been investigated. Also NOx level are compared in a diesel engine working as a conventional diesel and in HCCI mode.

Sign in / Sign up

Export Citation Format

Share Document