Study of Lubrication Oil Ignition in a Rapid Compression Machine Under Sporadic Pre-ignition Conditions PDF Download
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Author: Morgen Paul Sullivan
Publisher:
ISBN:
Category :
Languages : en
Pages : 97
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Book Description
In recent years, the industry has shifted toward down-sizing and turbo-charging spark ignition (SI) engines in an effort to increase fuel conversion efficiency. However, this has given rise to a destructive phenomenon known as sporadic pre-ignition (SPI). At low cranking speeds and high loads, engines have been observed to knock violently for brief and infrequent intervals. If allowed to continue, these periods of knock will result in a destroyed engine. This study looks at the propensity of lube oil vapor appearing in the cylinder as a cause for this phenomenon. The theory is that a local oil vapor/air mixture pocket may auto-ignite and start a flame in the charge. The pre-ignition would produce extreme knock. A rapid compression machine (RCM) was used to simulate this scenario and determine if oil vapor can cause SPI, and if so, to relate the auto-ignition tendency to the oil properties. The RCM was used to measure the ignition delay of a cloud of oil vapor in a stoichiometric gasoline/air mixture. The ignition delays were then correlated to chemical and physical properties of the oils. Finally, the effect of diluting the mixture was assessed. The results suggest that lube oil is a plausible source of SPI. The oil ignition delay times are sufficiently short to produce extreme pre-ignition consistent with SPI. Further supporting evidence lies in the fact that oil ignition delay times concur with SPI behavior in engines. It was found that the base stock, degradation, and chemical additives all play a role in oil ignition delay times. The results also demonstrate. that dilution significantly slows auto-ignition of the oil.
Author: Morgen Paul Sullivan
Publisher:
ISBN:
Category :
Languages : en
Pages : 97
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Book Description
In recent years, the industry has shifted toward down-sizing and turbo-charging spark ignition (SI) engines in an effort to increase fuel conversion efficiency. However, this has given rise to a destructive phenomenon known as sporadic pre-ignition (SPI). At low cranking speeds and high loads, engines have been observed to knock violently for brief and infrequent intervals. If allowed to continue, these periods of knock will result in a destroyed engine. This study looks at the propensity of lube oil vapor appearing in the cylinder as a cause for this phenomenon. The theory is that a local oil vapor/air mixture pocket may auto-ignite and start a flame in the charge. The pre-ignition would produce extreme knock. A rapid compression machine (RCM) was used to simulate this scenario and determine if oil vapor can cause SPI, and if so, to relate the auto-ignition tendency to the oil properties. The RCM was used to measure the ignition delay of a cloud of oil vapor in a stoichiometric gasoline/air mixture. The ignition delays were then correlated to chemical and physical properties of the oils. Finally, the effect of diluting the mixture was assessed. The results suggest that lube oil is a plausible source of SPI. The oil ignition delay times are sufficiently short to produce extreme pre-ignition consistent with SPI. Further supporting evidence lies in the fact that oil ignition delay times concur with SPI behavior in engines. It was found that the base stock, degradation, and chemical additives all play a role in oil ignition delay times. The results also demonstrate. that dilution significantly slows auto-ignition of the oil.
Author: Tairin Hahn
Publisher:
ISBN:
Category :
Languages : en
Pages : 162
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Book Description
As it becomes more and more difficult to find "easy" oil, various alternative fuels are introduced to the markets. These fuels have chemical properties that are different from the traditional gasoline and diesel fuels so that engine efficiency and other engine behaviors may be affected To improve engine efficiency and to identify which alternative fuel is the cleanest fuel solution, it is necessary to compile information about the ignition delay, which governs auto-ignition in spark-ignition (SI), compression-ignition (CI) and homogeneous charge compression-ignition (HCCI) engines. In this study, we measured ignition delay on the Rapid Compression Machine (RCM). RCM is a single-stroke device, which compresses uniform mixtures to engine-like condition. We can interpret from the pressure the detailed heat release process. A comprehensive ignition delay database of toluene/n-heptane mixtures and gasoline/ethanol mixtures was established The data allow us to calculate the auto-ignition behavior in engines. Depending on application the correct choice of alternative fuels may be made.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 14
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Book Description
The use of gasoline in homogeneous charge compression ignition engines (HCCI) and in duel fuel diesel - gasoline engines, has increased the need to understand its compression ignition processes under engine-like conditions. These processes need to be studied under well-controlled conditions in order to quantify low temperature heat release and to provide fundamental validation data for chemical kinetic models. With this in mind, an experimental campaign has been undertaken in a rapid compression machine (RCM) to measure the ignition of gasoline mixtures over a wide range of compression temperatures and for different compression pressures. By measuring the pressure history during ignition, information on the first stage ignition (when observed) and second stage ignition are captured along with information on the phasing of the heat release. Heat release processes during ignition are important because gasoline is known to exhibit low temperature heat release, intermediate temperature heat release and high temperature heat release. In an HCCI engine, the occurrence of low-temperature and intermediate-temperature heat release can be exploited to obtain higher load operation and has become a topic of much interest for engine researchers. Consequently, it is important to understand these processes under well-controlled conditions. A four-component gasoline surrogate model (including n-heptane, iso-octane, toluene, and 2-pentene) has been developed to simulate real gasolines. An appropriate surrogate mixture of the four components has been developed to simulate the specific gasoline used in the RCM experiments. This chemical kinetic surrogate model was then used to simulate the RCM experimental results for real gasoline. The experimental and modeling results covered ultra-lean to stoichiometric mixtures, compressed temperatures of 640-950 K, and compression pressures of 20 and 40 bar. The agreement between the experiments and model is encouraging in terms of first-stage (when observed) and second-stage ignition delay times and of heat release rate. The experimental and computational results are used to gain insight into low and intermediate temperature processes during gasoline ignition.
Author: Thorsten Schweizer
Publisher: Logos Verlag Berlin GmbH
ISBN: 3832582428
Category : Technology & Engineering
Languages : en
Pages : 140
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Book Description
The concept of increasing power density is a successful approach to improving the conflict between efficiency and emission behavior of spark-ignition engine drive units for light-duty vehicles. This leads to highly charged gasoline engines with direct injection and high specific torque and power densities, promoting a not yet fully understood combustion anomaly known as low-speed pre-ignition (LSPI). This unpredictable, multicyclic phenomenon limits the depictable in-cylinder pressures, further efficiency gains and engine reliability. Only with a holistic understanding of the LSPI root cause mechanisms and processes can targeted countermeasures be taken and further efficiency gains achieved. A novel methodology pathway for LSPI root cause analysis was developed to accompany the entire LSPI event emergence process path by means of a multi-experimental approach on a modern high efficiency engine. This includes the identification of key LSPI activity – engine parameter specification relations, minimally invasive high-speed endoscopic imaging and further LSPI key experiments. Only the accumulation of inorganic substances originating from lubricating oil additives enables specific deposits/particles to ignite the surrounding mixture over a multicyclic process due to the resulting increased oxidation reactivity. Through a final synthesis step of all results, a multi-cycle oxidation-reactivity-enhanced deposit/particle-driven LSPI root cause mechanism is established.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 23
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Book Description
Studying the details of hydrocarbon chemistry in an internal combustion engine is not straightforward. A number of factors, including varying conditions of temperature and pressure, complex fluid motions, as well as variation in the composition of gasoline, render a meaningful characterization of the combusting system difficult. Some simplified experimental laboratory devices offer an alternative to complex engine environments: they remove some of the complexities that exist in real engines but retain the ability to work under engine-relevant conditions. The choice of simplified experimental devices is limited by the range of temperature and pressure at which they can operate; only the shock tube and rapid compression machine (RCM) can reach engine-relevant temperatures and pressures quickly enough and yet withstand the high pressures that occur after the ignition event. Both devices, however, suffer a common drawback: the use of inert diluent gases has been shown to affect the measured ignition delay time under some experimental conditions. Interestingly, this effect appears to be opposite in the shock tube and RCM: in the comparative study of the carrier gases argon and nitrogen, argon decreases the ignition delay time in the shock tube, but increases it in the RCM. This observation is investigated in more detail in this study.
Author: Gautam Kalghatgi
Publisher: Springer Nature
ISBN: 9811687358
Category : Technology & Engineering
Languages : en
Pages : 339
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Book Description
This book focuses on gasoline compression ignition (GCI) which offers the prospect of engines with high efficiency and low exhaust emissions at a lower cost. A GCI engine is a compression ignition (CI) engine which is run on gasoline-like fuels (even on low-octane gasoline), making it significantly easier to control particulates and NOx but with high efficiency. The state of the art development to make GCI combustion feasible on practical vehicles is highlighted, e.g., on overcoming problems on cold start, high-pressure rise rates at high loads, transients, and HC and CO emissions. This book will be a useful guide to those in academia and industry.
Author: Arun S. P. Solomon
Publisher:
ISBN:
Category : Spark ignition engines
Languages : en
Pages : 17
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Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Author: Pyongwan Park
Publisher:
ISBN:
Category : Automobiles
Languages : en
Pages : 276
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Author: W. W. Haskell
Publisher:
ISBN:
Category : Combustion
Languages : en
Pages : 5
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