A new modeling approach of pressure waves at the inlet of internal combustion engines

This paper presents a new model used to describe the propagation of pressure waves at the inlet systems of internal combustion engine. In the first part, an analogy is made between the compressible air in a pipe and a mechanical ideal mass damper spring system. A new model is then presented and the parameters of this model are determined by the use of an experimental setup (shock tube test bench). With this model, a transfer function is defined in order to link directly the pressure and the air mass flow rate. In the second part, the model is included into an internal combustion engine simulation code. The results obtained with this code are compared to experimental ones which are measured on a one-cylinder engine test bench. This last one is driven by an electric motor in order to study only the effect of the pressure waves on the engine behavior. A good agreement is obtained between the experimental results and the numerical ones and the new approach is an alternative method for modeling the pressure wave phenomena in an internal combustion engine manifold.

Time-varying Performance Prediction and System Identification of Internal Combustion Engines

Design for life-time performance and proper maintenance measures are usually needed to prolong the mean-time-between-failures of complex equipments such as internal combustion engines.To reach this,it is important to obtain the information of time-varying system performance in design stage and to identify the structural change at each moment.So a multidisciplinary model based method is studied in this paper to unify the time-varying performance(TVP) prediction and system identification(SI) of equipments.The related multidisciplinary model in this paper should be not only precise to give simulation results but also sensitive to the variation of system parameters.So the varying history of system performance along with the structural change can be obtained from the model.Then the value of system parameters can be identified by seeking roots with given detected responding data and relationship between system responding data and system parameters.A case study on a low power gasoline engine shows that the method presented in this paper can provide useful information for the development and maintenance of complex equipments.

Influence of Valve's Characteristic on Total Performance of Three Cylinders Internal Combustion Water Pump

Intenal combustion pump （ICP） is a new type power device turning the thermal energy from fuel combustion into fluid pressure energy. Three cylinders prototype has just been developed. The study on the influence of valve＇s characteristic on ICP＇s total performance will found the base for its optimum design. Based on the theoretical and testing fruits of single cylinder prototype, the performance of the valves and complete appliance of the latest is simulated. When the natural frequency of valves is approximately to the round number times of the working frequency, volumetric efficiency is seriously low. The nominal rotational speed of the prototype is nearly to the speed where the volumetric efficiency is lowest, which is harmful to the normal work of ICP, so further structure optimization of valves should be carried out. The change of volumetric efficiency has great influence on the fuel consumption rate, output flow, effective thermal efficiency, effective power, and so on, but little on output pressure.

STEADY-STATE AND IDLE OPTIMIZA-TION OF INTERNAL COMBUSTION ENGINE CONTROL STRATEGIES FOR HYBRID ELECTRIC VEHICLES

A novel steady-state optimization （SSO） of internal combustion engine （ICE） strategy is proposed to maximize the efficiency of the overall powertrain for hybrid electric vehicles, in which the ICE efficiency, the efficiencies of the electric motor （EM） and the energy storage device are all explicitly taken into account. In addition, a novel idle optimization of ICE strategy is implemented to obtain the optimal idle operating point of the ICE and corresponding optimal parking generation power of the EM using the view of the novel SSO of ICE strategy. Simulations results show that potential fuel economy improvement is achieved relative to the conventional one which only optimized the ICE efficiency by the novel SSO of ICE strategy, and fuel consumption per voltage increment decreases a lot during the parking charge by the novel idle optimization of ICE strategy.

Non-linear Torsional Vibration Characteristics of an Internal Combustion Engine Crankshaft Assembly

Crankshaft assembly failure is one of the main factors that affects the reliability and service life of engines.The linear lumped mass method,which has been universally applied to the dynamic modeling of engine crankshaft assembly,reveals obvious simulation errors.The nonlinear dynamic characteristics of a crankshaft assembly are instructionally significant to the improvement of modeling correctness.In this paper,a general expression for the non-constant inertia of a crankshaft assembly is derived based on the instantaneous kinetic energy equivalence method.The nonlinear dynamic equations of a multi-cylinder crankshaft assembly are established using the Lagrange rule considering nonlinear factors such as the non-constant inertia of reciprocating components and the structural damping of shaft segments.The natural frequency and mode shapes of a crankshaft assembly are investigated employing the eigenvector method.The forced vibration response of a diesel engine crankshaft assembly taking into account the non-constant inertia is studied using the numerical integral method.The simulation results are compared with a lumped mass model and a detailed model using the system matrix method.Results of non-linear torsional vibration analysis indicate that the additional excitation torque created by non-constant inertia activates the 2nd order rolling vibration,and the additional damping torque resulting from the non-constant inertia is the main nonlinear factor.The increased torsional angular displacement evoked by the high order excitation torque relates to the non-constant inertia.This research project is aimed at improving nonlinear dynamics theory,and the confirmed nonlinear parameters can be used for the structure design of a crankshaft assembly.

Application of non-equal interval GM(1,1)model in oil monitoring of internal combustion engine

The basic difference non-equal interval model GM(1,1) in grey theory was used to fit and forecast data series with non-equal lengths and different inertias, acquired from oil monitoring of internal combustion engines. The fitted and forecasted results show that the length or inertia of a sequence affects its precision very much, i.e. the bigger the inertia of a sequence is, or the shorter the length of a series is, the less the errors of fitted and forecasted results are. Based on the research results, it is suggested that short series should be applied to be fitted and forecasted; for longer series, the newer datum should be applied instead of the older datum to be analyzed by non- equalinterval GM(1,1) to improve the forecasted and fitted precision, and that data sequence should be verified to satisfy the conditions of grey forecasting.

NO_x emission characteristics of hydrogen internal combustion engine

To study the economic advantages of hydrogen internal combustion engine, an experimen- tal study was carried out using a 2.0 L port fuel-injected （PFI） hydrogen internal combustion engine. Influences of fuel-air equivalence ratio φ, speed, and ignition advance angle on heat efficiency were determined. Test results showed that indicated thermal efficiency （ ITE ） firstly increased with fuel- air equivalence ratio, achieved the maximum value of 40. 4% （ φ = 0.3 ）, and then decreased when was more than 0. 3. ITE increased as speed rises. Mechanical efficiency increased as fuel-air equiva- lence ratio increased, whereas mechanical efficiency decreased as speed increased, with maximum mechanical efficiency reaching 90%. Brake thermal efficiency （BTE） was influenced by ITE and me- chanical efficiency, at the maximum value of 35% （φ =0.5, 2 000 r/min）. The optimal ignition ad- vance angle of each condition resulting in the maximum BTE was also studied. With increasing fuel- air equivalence ratio, the optimal ignition angle became closer to the top dead center （ TDC ）. The test results and the conclusions exhibited a guiding role on hydrogen internal combustion engine opti- mization.

Research on Simulation and Prediction of Internal Combustion Engine Structural Acoustic Radiation

With the purpose of efficiently predicting structural radiated noise of internal combustion engine（I.C.E.）,a new simulation technique is introduced,which is an approach based on boundary element method （BEM）,acoustic transfer vector（ATV） technique and coupled boundary element model and finite element model （BEM-FEM） approach.Analyses of vibration exciting loads,computing structural dynamic characteristics and dynamic responses have led to theoretical results,which are tested on an L6 diesel engine to validate this proposed technique in engineering practice.

Development of Valve Steel for Internal Combustion Engine in China

This paper first briefly introduces the history of the development of China valve steel from mainly adopting valve steel from the former Soviet Uinoin in the fifties, manufacturing by herself in the sixties, to introducing advanced valve steel from other countries and instituting Chinese valve steel system since the seventies.The demand of valve steel for China internal combustion engine including material specification and quantity required at present is discussed. The principal difficulties being faced with in the development of China valve steel at the moment are put forward. Finally, a detailed discussion is made on the development of China valve steel with suggstions of developing 5Cr8Si2 and MF811 martensitic steels, 21 2N austenitic steel used for gasoline engine, 23 8N austenitic steel used for diesel engine, 21 4NWNb high strength austenitic steel and LF2 and LF4 for valve alloy.[WT5”BZ〗

Improvement on Performances of Internal Combustion Engine Using the Technology of Ceramic Coating

This paper introduces a new technology of using ceramic coating on piston rings of an internal combustion engine, and the comparison of mechanical efficiency and performances of an actual engine before and after the application of ceramic coating on the piston rings. The experimental results show that the mechanical efficiency and power output are enhanced by 4% and 2.6%, respectively, with fuel consumption reduced by (2.9%.) Further studies on coating processing and coating materials as well as the reliability and durability will be of great significance in the application and popularization of the new technology.

Establishment of a CouplingModel for the Prediction of Heat Dissipation of the Internal Combustion Engine Based on Finite Element

The aerodynamics and heat transfer performance in the rear-mounted automobile cabin have an important influence on the engine’s safety and the operational stability of the automobile.The article uses STARCCM and GT-COOL software to establish the 3D wind tunnel model and engine cooling system model of the internal combustion engine.At the same time,we established a 3D artificial coupling model through parameter transfer.The research results show that the heat transfer coefficient decreases with the increase of the comprehensive drag coefficient of the nacelle.This shows that the cabin flow field has an important influence on the heat transfer coefficient.Themainstream temperature rise of the engine room increases with the increase of the engine load.It is proved that vehicle speed affects the amount of heat dissipation of the engine room internal combustion engine under certain load conditions.The article provides a more effective and fast calculation method for the research on the heat dissipation of the internal combustion engine and the optimization of the cooling system equipment.

Fault Identification of Internal Combustion Engine based on Support Vector Machine and Fuzzy Neural Network

The internal combustion engine is the main power source of current large⁃scale machinery and equipment.Overhaul and maintenance of its faults are important conditions for ensuring the safe and stable operation of machinery and equipment,and the identification of faults is a prerequisite.Therefore,the fault identification of internal combustion engines is one of the important directions of current research.In order to further improve the accuracy of the fault recognition of internal combustion engines,this paper takes a certain type of internal combustion engine as the research object,and constructs a support vector machine and a fuzzy neural network fault recognition model.The binary tree multi⁃class classification algorithm is used to determine the priority,and then the fuzzy neural network is verified.The feasibility of the model is proved through experiments,which can quickly identify the failure of the internal combustion engine and improve the failure processing efficiency.

Fault Diagnosis for IC Engines Using Wavelet Packet and Image Processing

There are few applications of image processing technology for diagnosing andstate monitoring for internal combustion (IC) engines, which is discussed in detail in this paper.The time-frequency distribution images of cylinder head vibration signals are obtained bydecomposing them with a wavelet packet algorithm. It is the first time that we look attime-frequency distribution images from the point of images. Based on this, a new method forapplying image processing technology for diagnosing and state monitoring for internal combustionengines is presented in this paper. A valve fault diagnosis model is set up by image matching, whichis realized on a four-stroke, six-cylinder diesel engine. At the same time, some notes arepresented in this paper. It has been proved that it is of no good effect to diagnose with histogramsof time-frequency images generated by cylinder head vibration signals that have been processed witha wavelet packet algorithm. The reason is given in this paper. Comparisons of diagnosing effect arecarried out between noise-added signals and original signals. It has little effect on diagnosingresults after signals have been added with noise. The results show that this method has a clearphysical meaning and is of good engineering practicability, feasibility, good precision and highspeed.

Simulation and Experiment for Oxygen-enriched Combustion Engine Using Liquid Oxygen to Solidify CO2

For capturing and recycling of CO2 in the internal combustion engine, Rankle cycle engine can reduce the exhaust pollutants effectively under the condition of ensuring the engine thermal efficiency by using the techniques of spraying water in the cylinder and optimizing the ignition advance angle. However, due to the water spray nozzle need to be installed on the cylinder, which increases the cylinder head design difficulty and makes the combustion conditions become more complicated. In this paper, a new method is presented to carry out the closing inlet and exhaust system for internal combustion engines. The proposed new method uses liquid oxygen to solidify part of cooled CO2 from exhaust system into dry ice and the liquid oxygen turns into gas oxygen which is sent to inlet system. The other part of CO2 is sent to inlet system and mixed with oxygen, which can reduce the oxygen-enriched combustion detonation tendency and make combustion stable. Computing grid of the IP52FMI single-cylinder four-stroke gasoline-engine is established according to the actual shape of the combustion chamber using KIVA-3V program. The effects of exhaust gas recirculation （EGR） rate are analyzed on the temperatures, the pressures and the instantaneous heat release rates when the EGR rate is more than 8%. The possibility of enclosing intake and exhaust system for engine is verified. The carbon dioxide trapping device is designed and the IP52FMI engine is transformed and the CO2 capture experiment is carried out. The experimental results show that when the EGR rate is 36% for the optimum EGR rate. When the liquid oxygen of 35.80-437.40 g is imported into the device and last 1-20 min, respectively, 21.50-701.30 g dry ice is obtained. This research proposes a new design method which can capture CO2 for vehicular internal combustion engine.

Full Cycle Cold Flow Analysis of the Effect of Twin Swirl Combustion Chamber Design in a Diesel Engine

New designs and adaptation methods are experimented to ensure compliance to ever increasing emissions and efficiency requirements of modern diesel engines. Piston head structure which influences the mixing rate and timing of the fuel within in the combustion chamber is known to enable increase in combustion efficiency and thus lower emission rates. In this paper, computation analysis of flow within a diesel engine cylinder with a twin swirl combustion chamber design throughout a full cycle is presented. The results obtained indicate that the effect of the twin swirl combustion chamber on the cold flow conditions is noteworthy and further analysis together with experiments may reveal information that may prove to be useful in further new designs.

Wear protection assessment of ultralow viscosity lubricants in high-power-density engines:A novel wear prediction algorithm

Durability and reliability have been studied for decades through intensive trial-error experimentation.However,there are numerous fields of application where the costs associated with this approach are not acceptable.In lubricated machines with severe dynamic loads,such as high-power-density engines,simulation tools offer clear advantages over intensive testing.Prototypes and multiple scenarios can be cost-effectively simulated to assess different lubricants and engine configurations.The work presented here details the study of wear based on a validated elastohydrodynamic(EHD)simulation model of the connecting rod journal bearing.This model accounts for elastic deformation through a connecting rod finite element model(FEM).In addition,multiple lubricant rheological and tribological dependences,determined by specific experimental tests,are applied in the model through their interaction with the simulation software.Correspondingly,a novel wear algorithm is proposed to predict wear depth over time evolution along a proposed wear cycle based on the typical working ranges of high-performance engines.A final assessment is presented to compare 4 different ultralow-viscosity lubricants in their protective performance under severe conditions.The results show the evolution of the wear load and wear depth over the wear cycle.This evaluation is key to describing a lubricant selection procedure for high-power-density engines.

Effect of temperature on tribofilm growth and the lubrication of the piston ring-cylinder liner system in two-stroke marine engines

This study is an optimized extension based on the authors’previous research on the tribo-chemical reaction under constant temperature field of two-stroke internal combustion engines(ICEs).It establishes a coupled analysis model that considers the tribo-chemical reactions,dynamic contact,and interface lubrication of the piston ring-cylinder liner(PRCL)system under transient temperature conditions.In this study,for the first time,the prediction of the tribofilm thickness and its influence on the surface micro-topography(the comprehensive roughness)are coupled in the working temperature field of the PRCL system,forming an effective model framework and providing a model basis and analytical basis for subsequent research.This study findings reveal that by incorporating temperature and tribofilm into the simulation model,the average friction deviation throughout the stroke decreases from 8.92%to 0.93%when compared to experimental results.Moreover,the deviation during the combustion regime reduces from 39.56%to 7.34%.The proposed coupled model provides a valuable tool for the evaluation of lubrication performance of the PRCL system and supports the analysis software forward design in two-stroke ICEs.

Fuel Economy Opportunities for Internal CombustionEngines by Means of Oil-Cooling

Comparative experiments of oil and water-cooling were performed on a 4-cylinder automotive gasoline engine and a single-cylinder direct injection Diesel engine. Measurements were made to investigate the variation of fuel consumption, combustor wall temperature and engine emissions (HC, CO, NOx and smoke) with two cooling media at steady-state conditions. Significant improvement of fuel economy was found mainly at partial load conditions with oil-cooling in comparison with the baseline waer-cooling both for the two engines. The experimental results also showed general trend of reduction in engine emissions using oil as the coolant. Measurements of wall temperature demonstrated that oil-cooling resulted in considerable increase of the combustor wall temperature and reduce of warmup period in starting process. For automotive gasoline engine, road tests indicated the same trend of fUel economy improvement with oil-cooling. The performance of the automotive oil-cooled engine was fUrther improved by internal cooling with water or methanol injection.

Exergy Analysis of Organic Rankine Cycles with Zeotropic Working Fluids

Waste heat recovery is one of the possible solutions to improve the efficiency of internal combustion engines.Instead of wasting the exhaust stream of an energy conversion system into the environment,its residual energy content can be usefully recovered,for example in Organic Rankine Cycles(ORC).This technology has been largely consolidated in stationary power plants but not yet for mobile applications,such as road transport,due to the limitations in the layout and to the constraints on the size and weight of the ORC system.An ORC system installed on the exhaust line of a bus powered by a natural gas spark ignition engine has been investigated.The thermal power available at engine exhaust has been evaluated by measuring gas temperature and mass flow rate during real driving operation.The waste thermal power has been considered as heat input for the ORC plant simulation.A detailed heat exchanger model has been developed because it is a crucial component for the ORC performance.The exergy analysis of the ORC was performed comparing different working fluids:R601,R1233zd(E)and two zeotropic blends of the two organic pure fluids.The model allowed the evaluation of the ORC produced energy over the driving cycle and the potential benefit on the engine efficiency.