Showing papers in "International Journal of Engine Research in 2012"
TL;DR: In this paper, the effects of changes in intake temperature and pressure on the pre-ignition of turbo-charged engines were investigated. But the results were limited to the case of turbocharged engines, and they were concluded from the evidence of engine pressure records.
Abstract: Earlier studies of pre-ignitions at hot surfaces are first reviewed. The concept of a critical radius of a hot pocket of gas, closely related to the laminar flame thickness, that is necessary to initiate a propagating flame, has been used successfully to predict relative tendencies of different fuel–air mixtures to pre-ignite. As the mixture is compressed, the thickness of potential laminar flames decreases, and when this becomes of the order of the thermal sheath thickness at the hottest surface, pre-ignition can occur there, creating a propagating flame. Measured engine pre-ignition ratings are shown to correlate well with laminar flame thicknesses. Predictions are made concerning the effects of changes in intake temperature and pressure on the pre-ignition of different fuels.A growing current concern is occasional gas-phase, autoignitive, pre-ignitions that can occur in turbo-charged engines, giving rise to very severe autoignition and knock. It is concluded from the evidence of engine pressure records...
229 citations
TL;DR: In this paper, the authors investigated reactivity controlled compression ignition operation on a four-cylinder light-duty diesel engine with production-viable hardware using conventional gasoline and diesel fuel and demonstrated diesel-like efficiency or better over the operating range explored with low engine-out nitrogen oxide and soot emissions.
Abstract: Reactivity controlled compression ignition is a low-temperature combustion technique that has been shown, both in computational fluid dynamics modeling and single-cylinder experiments, to obtain diesel-like efficiency or better with ultra-low nitrogen oxide and soot emissions, while operating primarily on gasoline-like fuels. This paper investigates reactivity controlled compression ignition operation on a four-cylinder light-duty diesel engine with production-viable hardware using conventional gasoline and diesel fuel. Experimental results are presented over a wide speed and load range using a systematic approach for achieving successful steady-state reactivity controlled compression ignition combustion. The results demonstrated diesel-like efficiency or better over the operating range explored with low engine-out nitrogen oxide and soot emissions. A peak brake thermal efficiency of 39.0% was demonstrated for 2600 r/min and 6.9 bar brake mean effective pressure with nitrogen oxide emissions reduced by an...
78 citations
TL;DR: In this article, the authors discuss the potential for increased emissions, increased fuel consumption, or engine damage due to failure of automotive engines, and suggest that these negative impacts may be prevented or at least alleviated if faul...
Abstract: Faults affecting automotive engines can potentially lead to increased emissions, increased fuel consumption, or engine damage. These negative impacts may be prevented or at least alleviated if faul...
69 citations
TL;DR: In this article, a flexible valve train for diesel engines is proposed to enable emissions reductions and fuel economy improvements in an advanced diesel engine architecture employing flexible valve trains, which enables engine designers to optimize the valve train.
Abstract: Advanced diesel engine architectures employing flexible valve trains enable emissions reductions and fuel economy improvements. Flexibility in the valve train allows engine designers to optimize th...
50 citations
TL;DR: In this article, a hybrid combustion control strategy in a partly premixed combustion diesel engine was developed and carefully optimized for high thermal efficiency and near-zero emissions in a wide engine with a wide output.
Abstract: A hybrid combustion control strategy in a partly premixed combustion diesel engine have been developed and carefully optimized for high thermal efficiency and near-zero emissions in a wide engine o...
46 citations
TL;DR: In this paper, the effects of fuel ignitability and volatility over a wide range of premixed low-temperature combustion (LTC) modes in diesel engines were investigated, and the combustion phasing was demonstrated to be a good indicator to estimate the in-cylinder peak pressure, exhaust gas emissions, and thermal efficiency in the LTC mode.
Abstract: A comprehensive study of fuel property effects in internal combustion engines is required to enable fuel diversification as well as the development of applications to advanced engines for operation with a variety of combustion modes. The objective of this paper is to investigate the effects of fuel ignitability and volatility over a wide range of premixed low-temperature combustion (LTC) modes in diesel engines. A total of 23 fuels were prepared from commercial gasoline, kerosene, and diesel as baseline fuels and with the addition of additives, to generate a cetane number (CN) range from 11 to 75. Experiments with a single-cylinder diesel engine operated in moderately advanced-injection LTC modes were conducted to evaluate these fuels. The combustion phasing is demonstrated to be a good indicator to estimate the in-cylinder peak pressure, exhaust gas emissions, and thermal efficiency in the LTC mode. Fuel ignitability affects the combustion phasing by changing the ignition delay. The predicted cetane numb...
34 citations
TL;DR: In this paper, experimental studies on deposits in engine combustion chambers, with emphasis on deposit composition, damage to engines, formation mechanisms and study methods, are presented. But, the authors do not consider the effects of these studies on engine performance.
Abstract: This article reviews experimental studies on deposits in engine combustion chambers, with emphasis on deposit composition, damage to engines, formation mechanisms and study methods. The existence o...
33 citations
TL;DR: In this article, it is shown that engine vibrations of large amplitude are caused by inertial effects of the piston-crankshaft mechanism and gas forces, and are transmitted to the chassis of a vehicle in the form of periodically va...
Abstract: Engine vibrations of large amplitude are caused by inertial effects of the piston–crankshaft mechanism and gas forces, and are transmitted to the chassis of a vehicle in the form of periodically va...
28 citations
TL;DR: In this article, the authors investigated a model-based transient calibration process for diesel engines and found that a significant improvement in transient emissions and fuel consumption and a sizable reduction in calibration time and test cell requirements is achieved.
Abstract: This is the first part of a study investigating a model-based transient calibration process for diesel engines. The motivation is to populate hundreds of parameters (which can be calibrated) in a methodical and optimum manner by using model-based optimization in conjunction with the manual process so that, relative to the manual process used by itself, a significant improvement in transient emissions and fuel consumption and a sizable reduction in calibration time and test cell requirements is achieved. Empirical transient modelling and optimization has been addressed in the second part of this work, while the required data for model training and generalization are the focus of the current work. Transient and steady-state data from a turbocharged multicylinder diesel engine have been examined from a model training perspective. A single-cylinder engine with external air-handling has been used to expand the steady-state data to encompass transient parameter space. Based on comparative model performance and ...
26 citations
TL;DR: In this paper, a common chemical-kinetic software was employed to simulate, for n-heptane and methane fuels, fixed local conditions (standard diesel and low-temperature combustion) described by constant pressure, relative mixture fraction, oxygen mass fraction and initial and final reaction time.
Abstract: Over the past two decades, the amount of exhaust gas pollutants emissions has been significantly reduced due to the severe emission legislation imposed in most countries worldwide. Initial strategies simply required the employment of simple after-treatment and engine control devices; however, as the restrictions become more stringent, these strategies are evolving in the development of different combustion modes, specially characterized by having low-temperature combustion characteristics. These new working conditions demand the need to check the suitability of the current NO predictive models that coexist nowadays under standard diesel combustion characteristics, paying closer attention to the Thermal mechanism. In order to do so, a common chemical-kinetic software was employed to simulate, for n-heptane and methane fuels, fixed local conditions (standard diesel and low-temperature combustion) described by constant pressure, relative mixture fraction, oxygen mass fraction and initial and final reaction t...
24 citations
TL;DR: A comprehensive engine to drive-cycle modelling framework has been developed for evaluating fuel economy improvements of new engine technologies as discussed by the authors, which comprises three key components: (a) full engine system models and routines for the generation of engine performance and fuel consumption maps; (b) an improved experimental heat release analysis and model calibration tool, which was created by coupling an in-house heat release program to an engine cycle simulation, and which can be used for model calibration and validation when experimental data are available.
Abstract: A comprehensive engine to drive-cycle modelling framework has been developed for evaluating fuel economy improvements of new engine technologies. The framework comprises three key components: (a) full engine system models and routines for the generation of engine performance and fuel consumption maps; (b) an improved experimental heat release analysis and model calibration tool, which was created by coupling an in-house heat release analysis program to an engine cycle simulation, and which can be used for model calibration and validation when experimental data are available; and (c) an integrated vehicle modelling and drive-cycle simulation platform for fuel economy assessment. The framework implementation has been demonstrated through a fuel economy study of three engine and combustion technologies: a conventional spark-ignition (SI) engine, a high compression ratio SI engine with early intake valve closing (EIVC), and a homogeneous-charge compression ignition engine (HCCI) employing a recompression valv...
TL;DR: In this article, results of an experimental investigation carried out in a modern diesel engine running at different operating conditions and fuelled with blends of gasoline-diesel and n-butan.
Abstract: In the present paper, results of an experimental investigation carried out in a modern diesel engine running at different operating conditions and fuelled with blends of gasoline–diesel and n-butan...
TL;DR: Experimental results show that the online time-sequence incremental and decremental LS-SVMs are superior to the other three typical methods and significantly shorten the function updating time as compared with function retraining from scratch.
Abstract: Fuel efficiency and pollution reduction relate closely to air-ratio (i.e. lambda) control among all the engine control variables. Lambda indicates the amount that the actual available air-fuel rati...
TL;DR: In this article, a model-based transient calibration process for diesel engines was investigated and it was shown that simple regression models perform better than more powerful methods such as neural networks or localized regression.
Abstract: This is the second part of a study investigating a model-based transient calibration process for diesel engines. The first part addressed the data requirements and data processing required for empirical transient emission and torque models. The current work focuses on modelling and optimization. The unexpected result of this investigation is that when trained on transient data, simple regression models perform better than more powerful methods such as neural networks or localized regression. This result has been attributed to extrapolation over data that have estimated rather than measured transient air-handling parameters. The challenges of detecting and preventing extrapolation using statistical methods that work well with steady-state data have been explained. The concept of constraining the distribution of statistical leverage relative to the distribution of the starting solution to prevent extrapolation during the optimization process has been proposed and demonstrated. Separate from the issue of ext...
TL;DR: In this article, the effects of hydraulic flow rate variation in combination with very high injection pressures are investigated for a single-cylinder research engine, which is based on a light-duty direct injection diesel engine.
Abstract: Injection pressure and hydraulic nozzle flow rate are significant parameters that influence mixture formation and combustion in the direct injection (DI) diesel combustion process. An injection pressure increase enhances mixture formation as well as combustion. Decreasing the hydraulic flow rate, by means of reducing spray hole orifice diameter, affects mixture formation primarily through improved gas entrainment processes. Both injection pressure increase and hydraulic flow rate decrease therefore benefit mixture formation and combustion, which cause less soot emissions. Thus, the application of higher exhaust gas recirculation rates to decrease nitrogen oxide emissions is possible. The objective of this paper is to determine the effects of hydraulic flow rate variation in combination with very high injection pressures.Engine tests are carried out using a single-cylinder research engine, which is based on a light-duty DI diesel engine. With a displacement of 755 cm3 per cylinder, the engines range betwee...
TL;DR: In this paper, the effects of fuel injection parameters on combustion-induced noise in a small single-cylinder direct-injection diesel engine used in a generator set are described.
Abstract: In this paper, the effects of fuel injection parameters on combustion-induced noise in a small single-cylinder direct-injection diesel engine used in a generator set are described. A range of fuel ...
TL;DR: In this paper, a phenomenological model is developed to enable parametric understanding of the combustion and emission characteristics of multiple-injection common rail direct injection engines, based on a two-zone formulation comprising of fuel-air spray and the surrounding air.
Abstract: The high-pressure multiple injections in common rail direct injection diesel engines offer a possibility of simultaneous reduction of exhaust smoke and oxides of nitrogen. The purpose of the present work is to develop a phenomenological model to enable parametric understanding of the combustion and emission characteristics of multiple-injection common rail direct injection engines. The model is based on a two-zone formulation comprising of fuel–air spray and the surrounding air. The model predictions for combustion and emissions are validated with measured results of different multiple-injection schedules available in the published literature. The effect of parametric variations of multiple-injection scheduling on emission characteristics are predicted using the proposed model. It is observed that the simultaneous reduction of oxides of nitrogen and smoke is possible with an optimized pilot fuel quantity and dwell between the injection pulses.
TL;DR: In this paper, the authors investigated the effect of hydrogen (H2) addition on the exhaust emissions of a 1999 Cummins ISM370 heavy-duty diesel engine with H2 continuously supplemented to intake air.
Abstract: This paper investigates the effect of hydrogen (H2) addition on the exhaust emissions of a 1999 Cummins ISM370 heavy-duty diesel engine with H2 continuously supplemented to intake air. Using the 13-mode European Stationary Cycle (ESC), the addition of 2 per cent H2 by volume increased the emissions of oxides of nitrogen (NOx) and nitrogen dioxide (NO2), but reduced nitric oxide (NO) emissions. The addition of 4 per cent H2 increased the emissions of NO, NO2, and NOx. When examined under constant load, the addition of H2 reduced the emissions of particulate matter (PM) and carbon monoxide (CO), but had very mild effects on hydrocarbon (HC) emissions. It was also shown that the reduction in PM emissions was due to the reduced diesel fuel flowrate rather than the improvement to the combustion efficiency of diesel fuel. However, the addition of a relatively large amount of H2 at medium to high (30–70 per cent) load substantially increased the emissions of NOx. This was due to an increase in maximum local comb...
TL;DR: In this article, a combustion control algorithm is presented that, in combination with rate shaping, allows closed-loop control of a cylinder pressure trace, given this system, it is possible to control the behavior of the entire combustion process.
Abstract: In this paper, a combustion control algorithm is presented that, in combination with rate shaping, allows closed-loop control of a cylinder pressure trace. Given this system, it is possible to control the behaviour of the entire combustion process. The paper starts with an explanation of the control algorithm that was developed based on iterative learning control. Consequently, the so-called α-process, which comprises a constant pressure rise, is presented as an example of the additional degrees of freedom gained. Based on the exact analysis of experimental results and combustion simulations, the effects of a peak pressure limitation on the emission behaviour of a single-cylinder engine powered by an α-process are analysed in detail. The capability of the developed control system to isolate certain effects of ideal combustion processes gives a wide range of possible further investigations. However, for practical applications, the use of injection rate shaping is coupled with high hardware costs. Therefore...
TL;DR: In an effort to reduce dependence on petroleum-based fuels and increase engine efficiency, fuel-flexible engines with advanced technologies, including variable valve timing, are being developed as discussed by the authors.
Abstract: In an effort to reduce dependence on petroleum-based fuels and increase engine efficiency, fuel-flexible engines with advanced technologies, including variable valve timing, are being developed. Fu...
TL;DR: In this paper, the authors presented the motivation behind the development of an active control turbocharger, along with the initial thinking that led to the basic concept of applying active flow control at the inlet to a turbo-charger turbine.
Abstract: In this paper, the motivation behind the development of an active control turbocharger is presented, along with the initial thinking that led to the basic concept of applying active flow control at the inlet to a turbocharger turbine. In addition, the concept of active control for turbochargers is analysed in depth with the purpose of presenting a theoretical basis for any subsequent application of this type of control of exhaust gas flow into a turbocharger turbine by providing the fundamental thermo-fluids background. Secondly, the aim was not only to merely present a theory summarising the behaviour of the exhaust gas flow occurring during turbocharger turbine inlet geometrical changes, but to also present the implications from the periodic nature of these geometric changes, in particular with respect to cycle performance results both for the turbocharger and for the engine. The effects of the application of active control turbochargers were demonstrated through testing of the first prototype active co...
TL;DR: In this paper, an optimization followed by a fuel-saving evaluation of a hybrid pneumatic-combustion engine that can be obtained by modifying a conventional internal combustion engine is described.
Abstract: In this paper, we describe an optimization followed by a fuel-saving evaluation of a new concept of a hybrid pneumatic–combustion engine that can be obtained by modifying a conventional internal co...
TL;DR: In this article, a single-cylinder diesel engine was used to investigate the potential of exhaust gas recirculation dilution stratification as a control technique for homogeneous charge compression ignition combustion with early direct injections.
Abstract: A single-cylinder diesel engine was used to investigate the potential of exhaust gas recirculation dilution stratification as a control technique for homogeneous charge compression ignition combustion with early direct injections. Experimental studies on both all-metal and optically accessible engines were performed to understand the processes involved when exhaust gas recirculation is introduced separately in the intake ports. Laser-induced fluorescence diagnostics were carried out in the optical engine in order to provide fuel and exhaust gas recirculation distributions.The results indicate that depending on the intake configuration, the exhaust gas recirculation stratification can be maintained until late timings corresponding to the combustion event, leading to decreased maxima of heat-release rates, as well as decreased combustion noise levels. This result suggests that exhaust gas recirculation stratification may be used as a control parameter for combustion speed and therefore may contribute to the...
TL;DR: In this article, a detailed multi-zone thermodynamic simulation for the direct-injection diesel engine combustion process was developed for the purpose of predicting heterogeneous type combustion systems, and the simulation was used to predict heterogeneous-type combustion systems.
Abstract: A detailed multi-zone thermodynamic simulation has been developed for the direct-injection diesel engine combustion process. For the purpose of predicting heterogeneous-type combustion systems, the...
TL;DR: In this paper, a cost-effective mild air hybrid engine concept for buses and commercial vehicles, RegenEBD, is presented, which is designed to convert kinetic energy into...
Abstract: In this paper, a novel cost-effective mild air hybrid engine concept for buses and commercial vehicles, RegenEBD, is presented. This air hybrid technology is designed to convert kinetic energy into...
TL;DR: In this article, a comparative experimental study for determining the functionality of a common-rail injection system used in light-duty diesel vehicles is presented, using two Bosch fuel-injection systems.
Abstract: This research paper presents a comparative experimental study for determining the functionality of a common-rail injection system used in light-duty diesel vehicles. Two Bosch fuel-injection system...
TL;DR: In this paper, a discrete multi-component fuel evaporation model was successfully integrated with a G-equation flame propagation combustion model, and the model was shown to be effective in the discrete multiscale model.
Abstract: A discrete multi-component fuel evaporation model has been successfully integrated with a G-equation flame propagation combustion model. In the discrete multi-component fuel evaporation model, the ...
TL;DR: In this paper, the authors report the measurement of emissions from diesel-style combustion of a single-cycle, free-piston research device capable of achieving compression ratios up to 100:1.
Abstract: As part of an ongoing effort to demonstrate operation of a free-piston internal combustion engine at extremely high compression ratios, this paper reports the measurement of emissions from diesel-style combustion of a single-cycle, free-piston research device capable of achieving compression ratios up to 100:1. The ability to measure gaseous and particulate emissions was added to the existing extreme-compression device. These systems and their characterization are described. Concentrations as well as specific emissions are reported for carbon monoxide, total oxides of nitrogen, unburned hydrocarbons, carbon dioxide, oxygen, and soot. A first set of emissions data is reported of a pure-component fuel (isooctane) at a moderate compression ratio (∼35:1) over a range of equivalence ratios, in order to characterize the emission measurement system as well as diesel-style combustion in the free-piston device. NOx emissions were essentially constant over the range of equivalence ratios. CO, HC, and soot emissions...
TL;DR: In this article, a hybrid pneumatic-combustion engine was proposed to convert mechanical energy into compressed air and convert compressed air back into mechanical energy, where the potential application for the concept is any use of the internal combustion engine where the load oscillates between a negative and a positive value.
Abstract: This work is a part of a research program that aims to modify a conventional internal combustion engine and turn it into a hybrid pneumatic–combustion engine. The hybrid pneumatic–combustion engine should be able to convert mechanical energy into compressed air and convert compressed air back into mechanical energy. The potential application for the concept is any use of the internal combustion engine where the load oscillates between a negative and a positive value, such as automobiles and hybrid wind diesel systems for remote area power generation. In the first application, during vehicle decelerations, an excess of power occurs, and a negative load could be applied to the engine, whereas during vehicle accelerations, a positive load is applied. In the second application, if the generated wind power is higher than consumption demand, then the load applied to the engine could be negative, and if the generated wind power is lower than consumption demand, then the load is positive. In previous work, we exp...
TL;DR: In this article, the performance of a turbo compressor for automo-compressor is represented using maps, measured for one set of inlet conditions and corrections are then applied to scale the performance to other inlet condition.
Abstract: Turbo performance is represented using maps, measured for one set of inlet conditions. Corrections are then applied to scale the performance to other inlet conditions. A turbo compressor for automo ...