Diagnosis methodology for the turbocharger groups installed on a 1 MW internal combustion engine

The issue of internal combustion engine (ICE) diagnosis attracts great interest because modern engines need continual control of the operational status, in order to obtain high efficiency in energy conversion and accurate control of the polluting emissions. In particular, in reference to an alternative ICE of 1 MW, the present study relates the development, through the design of neural simulators, of the turbocharger maps to reproduce the operational states characterized by new&clean conditions and allowing the evaluation of particular “health state” indices of such a module. In detail, after an experimental campaign, turbocharger fundamental characteristics referred to new&clean conditions, such as the compressor isoentropic efficiency and the mass flow elaborated by the turbine, were evaluated at different operation conditions of the alternative ICE Subsequently, the neural simulators were developed through the training and test of different neural architectures.     

Modeling of a 1 MW cogenerative internal combustion engine for diagnostic scopes

This paper contributes to the development of a thermo-dynamic model of the 1 MW cogenerative internal combustion engine (I.C.E.), including also an artificial neural network simulator of the electronic control module. Such a study is part of a more wide research activity, concerning the development of a diagnosis and monitoring system specifically for power plants. In particular, the engine model was realized to simulate the engine functioning also in the case of malfunctions and failures occurrence, taking in consideration the compensation effect operated by the regulation system.     

Fuzzy control of a bio-hydrogen internal combustion engine generating system

This study proposes a fuzzy control bio-hydrogen internal combustion engine (ICE) generating system. The ICE technology is composed of thermodynamics, mechanical engineering, hydrodynamics, and electrical engineering. Bio-hydrogen can provide clean and efficient power instead of conventional fuels applied in an ICE. The two critical cores of hydrogen ICE generator are ignition time control which can precisely ignite air-fuel mixtures to make generator output stable power and air-fuel ratio control which can adjust output power to satisfy load demand. Fuzzy logic can provide precise control and response fast within various air-fuel ratios.The study establishes a fuzzy control system with an output generator and an ICE with solenoid valve that controls bio-hydrogen injection. The experimental system successfully output stable power and carried out parameters of bio-hydrogen flow rate, air-fuel ratio, injection pressure, and ignition timing. Parameters and experimental data are analyzed in the study and can be references for future development of the bio-hydrogen internal combustion engine generating system.     

内燃机冷热电联产系统设计点性能分析

简介内燃机冷热电联产系统的发展现状,总结了发电用内燃机在设计点工况下主要参数的现有分布范围:排气温度约为450~600℃,排气流量基本上与额定功率呈线性关系,发电效率一般在33%~45%。对联产系统不同形式的能量输出、联产系统经济效率等进行分析研究,表明联产系统回收的能量主要来自排气和冷却水,排气回收能量一般高于冷却水回收能量。与热电联产系统相比,由于制冷比供热困难,冷热电联产系统的经济效率较高。     

Performance and emissions characteristics of a hydrogen enriched LPG internal combustion engine at 1400 rpm

Environmental concerns and depletion in petroleum resources have forced researchers to concentrate on finding renewable alternatives to conventional petroleum fuels. Hydrogen is thought to be a major energy resource of the future due to its clean burning nature and eventual availability from renewable sources. Hydrogen is widely regarded as a promising transportation fuel because it is clean and renewable.The authors manufactured a high accuracy heavy-duty variable compression ratio single cylinder engine to investigate its performance and emissions characteristics. The test engine was run at 1400 rpm with a compression ratio of 8. Spark timing was set to MBT (minimum spark advance for best torque). This paper investigates the effects of hydrogen enriched LPG fueled engine on exhaust emission, thermal efficiency and performance.     

一种新概念内燃机--基于多孔介质燃烧技术的超绝热发动机

多孔介质中的超绝热燃烧是一种先进的燃烧技术，具有高效低污染的特点。将这一技术应用于发动机领域，有可能引起内燃机技术和产业的一场重大革新。介绍超绝热燃烧的概念，讨论了多孔介质中往复流动下超绝热燃烧的特点，对多孔介质发动机的工作循环作了简单的热力学分析。在此基础上，对当前国外超绝热发动机的基础研究进行综述，着重介绍了分别由美国、日本和德国提出的三种超绝热发动机的方案的理论和实验研究进展，以期引起我国内燃机界对这一发展动向的关注。     

内燃机活塞成组编码系统

内燃机活塞的生产方式已经由少品种、大批量演变为多品种、变批量的形式。本文采用成组技术的哲理，建立了内燃机活塞HSDM编码系统，用于在计算机辅助工艺设计过程对零件几何信息和工艺信息的表达。该编码系统也可应用在企业产品设计、生产管理等其它过程。     

Diagnosis of internal combustion engine through vibration and acoustic pressure non-intrusive measurements

The present study proposes a diagnosis methodology for internal combustion engines (I.C.E.) working conditions, by means of non-invasive measurements on the cylinder head, such as acoustic and vibration, related to the internal indicated mean effective pressure. The experimental campaign was carried out on the internal combustion engine of the cogeneration plant at the Faculty of Engineering – University of Perugia (Italy), for different values of the engine load. Results show that both the vibration and acoustic signals measured on the cylinder head are strictly related to the phenomena inside the cylinder, depending on the engine load and the combustion frequency. Some vibration and acoustic indexes were introduced, in order to evaluate the working regimen of the engine. Their values, obtained for different engine loads, constitute the reference values; when the methodology was implemented, the evaluation of such indexes allows to estimate the combustion quality, comparing measured and reference values.     

Production function of a simple model internal combustion engine

The paper deals with an analysis in terms of production function of a simplified Beau de Rochas irreversible engine. The combustion reaction is the main source of irreversibility. The production function is concave. This property is an extension of similar behaviours for endoreversible heat engines.     

Performance analysis of a novel eco‐friendly internal combustion engine cycle

The Miller cycle applications have been performed to diminish NO_x released from internal combustion engines (ICEs), in recent years. The Miller cycle provides decreased compression ratio and enhanced expansion ratio; hereby, maximum in‐cylinder combustion temperatures diminish, and NO_x formations slow down remarkably. Another less‐known method is Takemura cycle application, which provides heat addition into engine cylinder at constant combustion temperatures. In this study, a novel cycle including the Miller cycle and the Takemura cycle has been developed by using novel numerical models and computing methods with seven processes and a novel way to decrease NO_x emissions at higher levels compared with the single applications of known cycles. A comprehensive performance examination of the proposed cycle engine in terms of performance characteristics such as effective power (EFP), effective power density (EFPD), exergy destruction (X), exergy efficiency (ε), and ecological coefficient of performance (ECOP) has been conducted. The impacts of engine operating and design parameters on the performance characteristics have been computationally examined. Furthermore, irreversibilities depending on incomplete combustion loss (INCL), exhaust output loss (EXOL), heat transfer loss (HTRL), and friction loss (FRL) have been considered in the performance simulations. The minimum exergy destruction and maximum performance specifications have been observed with 30 of the compression ratio. Maximum effective power values have been obtained at range between 1 and 1.2 of equivalence ratio. The optimum range for exergy efficiency is between 0.8 and 1 of equivalence ratio. Increasing engine speed has provided enhancing effective power. However, an optimum range has been found for the exergy efficiency that is interval of 3000 to 4000 rpm. The results obtained can be assessed by researchers studying on modeling of the engine systems and designs.     

Study on the design of inlet and exhaust system of a stationary internal combustion engine

The design and operational variables of inlet and exhaust systems are decisive to determine overall engine performance. The best engine overall performance can be obtained by proper design of the engine inlet and exhaust systems and by matching the correct turbocharger to the engine. This paper presents the results of investigations to design the inlet and exhaust systems of a stationary natural gas engine family. To do this, a computational model is verified in which zero dimensional phenomena within the cylinder and one dimensional phenomena in the engine inlet and exhaust systems are used. Using this engine model, the effects of the parameters of the inlet and exhaust systems on the engine performance are obtained. In particular, the following parameters are chosen: valve timing, valve diameter, valve lift profiles, diameter of the exhaust manifold, inlet and exhaust pipe lengths, and geometry of pipe junctions. Proper sizing of the inlet and exhaust pipe systems is achieved very precisely by these investigations. Also, valve timing is tuned by using the results obtained in this study. In general, a very high improvement potential for the engines studied here is presented.     

Combination of a vacuum solar collector system and an internal combustion engine in a local heat network

Different measures to reduce the space heating consumption can contribute to a more rational use of energy. Such measures are for example the use of solar collectors and the application of the principle of cogeneration by block-type thermal power stations (BTP) with internal combustion engines. This contribution presents some part of the results of an investigation in which the dimensioning of an internal combustion engine under the special conditions of the combination with a solar-heating system was analyzed. Concerning the course of the yearly duration curve which is an important criterion in dimensioning a BTP it can be found out that the shape of the course looks like a step. This is suitable for the block-type thermal power station if the thermal power of the combustion engine modules is chosen in a way that they fit in these steps.     

Energy and exergy analysis of a turbocharged hydrogen internal combustion engine

This paper has analyzed the energy and exergy distribution of a 2.3 L turbocharged hydrogen engine by mapping characteristics experiment. The energy loss during fuel energy conversion mainly includes: exhaust energy (23.5–34.7%), cooling medium (coolant and oil) energy (21.3–34.8%), intercooler energy (0.5–3.6%) and uncounted energy (5.8–14.1%), while the proportion of effective work ranges from 25.7% to 35.1%. Results show that all kinds of energies increase with engine speeds and they are not sensitive to the loads. However, the proportions of different kind of energy exhibit different characteristics. Moreover, the turbocharger can increase the brake thermal efficiency and the maximum can be increased by 4.8%. Exergy analysis shows exergy efficiency of the coolant energy does not exceed 5%, while the exergy efficiency of the exhaust energy can reach up to 23%. And the total hydrogen fuel thermal efficiency limit is theoretically above 59%.     

Backfire control and power enhancement of a hydrogen internal combustion engine

Frequent backfire can occur in inlet port fuel injection hydrogen internal combustion engines (HICEs) when the equivalence fuel–air ratio is larger than 0.56, thus limiting further enhancement of engine power. Thus, to control backfire, an inlet port fuel injection HICE test system and a computational fluid dynamics model are established to explore the factors that cause backfire under high loads. The temperature and the concentration of the gas mixture near the intake valves are among the essential factors that result in backfire. Optimizing the timing and pressure of hydrogen injection reduces the concentration distribution of the intake mixture and the temperature of the high-concentration mixture through the inlet valve, thus allowing control of backfire. Controlling backfire enables a HICE to work normally at high equivalence fuel–air ratio (even beyond 1.0). A HICE with optimized hydrogen injection timing and pressure demonstrates significant enhancement of the power output.     

Impact of carbon tax on internal combustion engine size selection in a medium scale CHP system

Combined heat and power (CHP) systems due to their high efficiency compared to the conventional power generation systems have received considerable attention as they have less harmful impact on the environment. Recently, the serious concern with reducing the greenhouse gas emissions has focussed the attention on the possibility of a carbon tax in some countries. Here, we address the impact of such tax on the sizing and economics of a CHP system.     

Experimental investigation of combustion characteristics and NOx emission of a turbocharged hydrogen internal combustion engine

In order to alleviate the contradictions of increasingly prominent environmental pollution, greenhouse gas emissions and oil resource security issues, the search for renewable and clean alternative energy sources is getting more and more attention. Hydrogen energy is known as a future energy source because of its safety, reliability, wide range of resources and non-polluting products. Hydrogen internal combustion engine combines the technical advantages of traditional internal combustion engines and has comprehensive comparative advantages in terms of manufacturing cost, fuel adaptability and reliability. It is one of the practical ways to realize hydrogen energy utilization. In this paper, the combustion characteristics and NOx emission of a turbocharged hydrogen engine were investigated using the test data. The results showed the combustion duration (the crank angle of 10%–90% fuel burned) at 1500 rpm and 2000 rpm was equal and the combustion duration is much bigger than the other loads when the BMEP is 0.27 MPa. The reason is the effect of the turbocharger on the gas exchange process, which will influence the combustion process. The cylinder pressure and pressure rise rate were also investigated and the peak pressure rise rate was lower than 0.25 MPa/°CA at all working conditions. Moreover, the NOx emission changed from 300 ppm to 1200 ppm with engine speed increasing and the maximum value can reach to 7000 ppm when the equivalence ratio is 0.88 at 2500 rpm, maximum brake torque. The NOx emission shows different changing tendencies with different working conditions. Finally, these conclusions can be used to develop controlling strategies to solve the contradictions among power, brake thermal efficiency and NOx emission for the turbocharged hydrogen internal combustion engines.     

Multi-objective optimization of internal combustion engine by means of 1D fluid-dynamic models

The definition of an efficient optimization methodology for internal combustion engine design using 1D fluid dynamic simulation models is presented. This work aims at discussing the fundamental numerical and fluid dynamic aspects which can lead to the definition of a best practice technique, depending on the complexity of the problem to be dealt with, on the number of design parameters, objective variables and constrains. For these reasons, both single-and multi-objective problems will be addressed, where the former are still of relevant interest (i.e. optimization of engine performances), while the latter have a much wider range of applications and are often characterized by conflicting objectives.     

Finding a suitable catalyst for on-board ethanol reforming using exhaust heat from an internal combustion engine

Ethanol steam reforming with pure ethanol and commercial bioethanol (S/C = 3) was carried out inside the housing of the exhaust gas pipe of a gasoline internal combustion engine (ICE) by using exhaust heat (610–620 °C). Various catalytic honeycombs loaded with potassium-promoted cobalt hydrotalcite and with ceria-based rhodium–palladium catalysts were tested under different reactant loads. The hydrogen yield obtained over the cobalt-based catalytic honeycomb at low load (F/W < 25 mL_liq·g_cat^?1·h^?1, GHSV = 4·10² h^?1) was remarkably high, whereas that obtained over the noble metal-based catalytic honeycombs was much superior at high loads (F/W = 25–150 mL_liq·g_cat^?1·h^?1, GHSV = 4·10²–2.4·10³ h^?1). At higher reactant loads the overall hydrogen production was limited by heat transfer from the exhaust heat to the reformer inside the housing of the exhaust gas pipe of the ICE. Extensive carbon deposition occurred over the cobalt-based honeycomb, making its use impractical. In contrast, stability runs (>200 h) at high load (F/W = 150 mL_liq·g_cat^?1·h^?1, GHSV = 2.4·10³ h^?1) showed that promotion of the ceria-supported noble metal catalyst with alumina and zirconia is a key element for practical application using commercial bioethanol. HRTEM analysis of post mortem honeycombs loaded with RhPd/Ce_0.5Zr_0.5O₂–Al₂O₃ showed no carbon formation and no metal agglomeration.     

Analysis of heat release dynamics in an internal combustion engine using multifractals and wavelets

In this paper we analyze data from previously reported experimental measurements of cycle-to-cycle combustion variations in a lean-fueled, multi-cylinder spark-ignition (SI) engine. We characterize the changes in the observed combustion dynamics with as-fed fuel–air ratio using conventional histograms and statistical moments, and we further characterize the shifts in combustion complexity in terms of multifractals and wavelet decomposition. Changes in the conventional statistics and multifractal structure indicate trends with fuel–air ratio that parallel earlier reported observations. Wavelet decompositions reveal persistent, non-stochastic oscillation modes at higher fuel–air ratios that were not obvious in previous analyses. Recognition of these long-time-scale, non-stochastic oscillations is expected to be useful for improving modelling and control of engine combustion variations and multi-cylinder balancing.     

Design of the measurements validation procedure and the expert system architecture for a cogeneration internal combustion engine

A research activity has been initiated to study the development of a diagnostic methodology, for the optimization of energy efficiency and the maximization of the operational time in those conditions, based on artificial intelligence (AI) techniques such as artificial neural network (ANN) and fuzzy logic.The diagnostic procedure, developed specifically for the cogeneration plant located at the Engineering Department of the University of Perugia, must be characterized by a modular architecture to obtain a flexible architecture applicable to different systems. The first part of the study deals with the identifying the principal modules and the corresponding variables necessary to evaluate the module “health state”.Also the consequent upgrade of the monitoring system is described in this paper. Moreover it describes the structure proposed for the diagnostic procedure, consisting of a procedure for measurement validation and a fuzzy logic-based inference system. The first reveals the presence of abnormal conditions and localizes their source distinguishing between system failure and instrumentation malfunctions. The second provides an evaluation of module health state and the classification of the failures which have possibly occurred. The procedure was implemented in C++.