Intake Valve Research Articles

Miller Cycle with Early Intake Valve Closing in Marine Medium-Speed Diesel Engines

Miller Cycle with Early Intake Valve Closing in Marine Medium-Speed Diesel Engines

Analysis of a tumbling motion using a clustering algorithm on dual-piv measurements: application to the in-cylinder flow of a miller cycle engine

This paper aims to study the internal aerodynamics of a Miller cycle gasoline engine. This cycle uses an over-expanded stroke to recover more work, for the same amount of fuel, than the classical Otto cycle. To achieve this, the effective compression stroke is made smaller than the expansion one by closing the intake valves prematurely. The in-cylinder tumble flow then stops being driven by the valve jet before the piston reaches the bottom dead center, which disturbs the movement. The flow is observed here on a motored single-cylinder transparent engine coupled to a dual-PIV system. This system allows two velocity fields per engine cycle to be measured. The temporal evolution of the flow structures could thus be followed, while keeping the high number of instantaneous fields measured by the traditional PIV systems. The data are then well adapted to statistical analysis. A clustering analysis method, using the k-means algorithm and adapted to dual-PIV data, is described here. The first part presents a method defining a criterion on the instantaneous center of rotation of the tumble motion that can improve the rotation rates by 17%. A second analysis classifies the velocity fields into three groups of strong, medium and weak rotation intensity. The evolution of the characteristic quantities of each group shows that the movements with high rotation rates, created upstream of the compression phase, can give high turbulence rates close to the top dead center of the piston.Graphical abstract

Numerical Investigation of the Application of Miller Cycle and Low-Carbon Fuels to Increase Diesel Engine Efficiency and Reduce Emissions

In this paper, validated simulations using Ricardo WAVE have been performed to investigate the effect of the Miller cycle and low-carbon fuels on the performance (power, torque, BTE and BSFC) and emissions of a diesel engine. The results show that the increased Miller cycle effect (larger deviation of the advanced or retarded intake valve closing from the standard intake valve closing time) will decrease NOx, CO and HC emissions, and slightly improve brake thermal efficiency (BTE) and brake specific fuel consumption (BSFC) with slight loss in engine performance and increase in soot emissions. An engine running B0 (diesel with 0% Biodiesel in the blend) with a −18% Miller cycle effect has a reduction in NOx of 9% and CO of 4.3% with a decrease of 1.6% in power at the rated engine speed. Using low carbon fuels drastically reduces emissions with reduced BTE and increased BSFC. When used in conjunction, the Miller cycle and low-carbon fuels have an improved effect on both performance and emissions. The optimal results demonstrate that using B60 (60% Biodiesel in the blend) and a −8% Miller effect contributes to a 1.5% improvement in power, 1.2% in BTE, 13.3% in NOx, 38.5% in CO, 8.9% in HC, and 33.0% in soot at a cost of 6.0% increase in BSFC. The results show that it is an easy way to reduce NOx, CO, HC and soot emissions and increase the BTE of the engine by combining Miller cycle and low-carbon fuels.

Comparision Deposit Formation On The Valve Diesel Engine Caused By Biodiesel And Petroleum Diesel Fuels

The research on the infl uence of the biodiesel to the formation of deposits on the intake and exhaust valves diesel engine has been carried out by means analysis of merit rating. The fuels used on this study are FAME (B-100), a mixture of 50% (v)of FAME in diesel fuel 48 (B-50), and diesel fuel 48 (B-0). The objective of this research is to obtain data which represent the infl uence of the biodiesel to the formation of deposits on the intake and exhaust valve diesel engine. The test used a diesel engine driving 5 KVA generator which is operated for 100 hours with 1.000 Watt electrical load. The results of the study show that the use of either FAME or biodiesel as alternative fuel in the diesel engine generator 5 KVA has a positive effect on reducing the deposit on the intake and exhaust valves.

THE INFLUENCE OF OLEFIN CONTENT IN GASOLINE AGAINST DEPOSIT BUILD UP ON INTAKE VALVE OF MOTOR BIKE ENGINE

The specification of gasoline 91, according to Dirjen Migas decree No. 3674 K/24/DJM/2006 dated March,17 2006 define the limit (maximum) of aromatic content 50%volume, and benzene 5.0% volume, but does not define boundary for olefin content as its is regulated in others countries. Olefin compound happened to be saturated hydrocarbon, its has higher octane number, unstable, produces gum that later on could build up as deposit on intake valve of combustion chamber or nozzle tip of fuel injection system. The objective of this study was to know how far the influence of olefin content in gasoline 91 to deposit build-up in intake valve of motor bike engine after cruising on road test for certain distance. For this purpose, the motor bike will be fueled with gasoline 91 with olefin content variations and will be compared to motor bike that cruised at the same route and distance accumulation with regular gasoline 91. Effect of several volume variety of olefin content in gasoline againts deposit development of intake valve engine will be discuss in this paper.

The Influence Of Olefin Content In Gasoline Against Deposit Build Up On Intake Valve Of Motor Bike Engine

The specification of gasoline 91, according to Dirjen Migas decree No. 3674 K/24/DJM/2006 dated March,17 2006 define the limit (maximum) of aromatic content 50% volume, and benzene 5.0% volume, but does not define boundary for olefin content as its is regulated in others countries. Olefin compound happened to be saturated hydrocarbon, its has higher octane number, unstable, produces gum that later on could build up as deposit on intake valve of combustion chamber or nozzle tip of fuel injection system. The objective of this study was to know how far the influence of olefin content in gasoline 91 to deposit build-up in intake valve of motor bike engine after cruising on road test for certain distance. For this purpose, the motor bike will be fueled with gasoline 91 with olefin content variations and will be compared to motor bike that cruised at the same route and distance accumulation with regular gasoline 91. Effect of several volume variety of olefin content in gasoline againts deposit development of intake valve engine will be discuss in this paper.

Simulation Analysis of Fuel Economy of the GDI Engine with a Miller Cycle and EGR Based on GT-Power

A one-dimensional (1D) simulation calculation model was created using GT-Power software to investigate the effect of an exhaust gas recirculation (EGR) in concert with the Miller cycle on engine fuel economy and using a 1.5 T gasoline direct injection (GDI) engine as the source engine. The engine was tested under partial loading, full loading, and declared working conditions. The results show that under partial load, the Miller cycle could improve engine fuel economy by reducing pumping losses. In the low-speed 1000 r/min full load region, the Miller cycle had a significant effect on increasing the engine fuel economy. When the Miller intensity was −29 °CA, the fuel consumption decreased by a maximum of 10.5%. At medium speeds, 2000 r/min to 3600 r/min, the Miller cycle did not improve fuel economy significantly. For the Miller cycle with late intake valve closure (LIVC), when the EGR rate was about 7%, the fuel consumption was reduced by about 1.3% compared with the original engine at the same EGR rate. When opposed to the original engine without EGR, the fuel consumption was lowered by approximately 3.2 percent.

Thermodynamic analysis of improving fuel consumption of natural gas engine by combining Miller cycle with high geometric compression ratio

The goal of this work is to solve the problem of low thermal efficiency of stoichiometric natural gas engines by combining the Miller cycle with a high geometric compression ratio (GCR). A one-dimensional thermodynamic model of a stoichiometric natural gas engine with turbocharger is established, and its effectiveness is verified by experimental data. On this basis, the influence of the high GCR combined with the Miller cycle achieved by early intake valve closing (EIVC) or late intake valve closing (LIVC) on the fuel consumption is studied in detail. The results show that the reasonable matching of the GCR and intake valve lift profile is beneficial to improve fuel consumption. The upper limit of fuel consumption improvement is determined by the performance of the turbocharger. The EIVC50 + GCR14 and LIVC75 + GCR13.5 solutions can not only ensure that the load and knock level are consistent with the baseline engine (IVC558 + GCR11.5), but also obtain the optimal fuel economy. Thermodynamic analysis further reveals the fuel-saving mechanism. The fuel consumption can be improved by 4.1%, mainly thanks to a good balance between theoretical efficiency and combustion loss. In addition, the reduction in gas exchange loss further improves fuel consumption. Unfortunately, the increase in heat transfer loss and friction loss limits the further improvement in fuel consumption.

Optimization Analysis of Locomotive Diesel Engine Intake System Based on Matlab-Simulink and GT-Power

In this paper, based on the coupling calculation of Simulink software and GT-Power software, an Optimizer model method was proposed for a 16V265H diesel engine to study the effects of different ratios of biodiesel (B0, B10, and B20) on the performance of a 16V265H diesel engine at 1000 rpm and 75% load. Firstly, the four parameters of diesel engine power, BSFC, soot emission, and NOx emission were taken as the result variables of the optimization model. Taking the intake and exhaust timing of the diesel engine as the independent variable of the optimization model, the maximum power, minimum BSFC, and minimum diesel engine emission were studied and analyzed. Finally, the performance parameters were comprehensively analyzed to determine the best intake and exhaust valve timing. Moreover, based on the model optimization, the diesel engine’s BSFC and power performance were compared, and the optimal intake timing scheme for the diesel engine with different biodiesel ratios at 75% operating conditions was obtained. The results showed that the maximum power, optimum BSFC, and minimum emissions of the 16V265H diesel engine with different ratios of biodiesel and different intake valve timing angles were also different. Under 75% load conditions, the BSFC reduction rate was up to 6.32%, and the power increase rate was up to 5.87%. In addition, by optimizing the model with B10 biodiesel and the intake valve timing close to 202°CA and the exhaust valve timing close to 98°CA, the diesel engine had the lowest NOx emission; with B10 biodiesel and the intake timing at 180°CA, the diesel engine had the lowest BSFC; and with B10 biodiesel and the intake valve timing close to 179.5°CA, the diesel engine had the maximum power. In conclusion, the diesel engine is best with B10 biodiesel. This research method can provide a reference for implementing variable intake system technology for the 16V265H diesel engine.

The Effect of Intake Valve Timing on Spark-Ignition Engine Performances Fueled by Natural Gas at Low Power

To reduce the greenhouse effect, it is important to reduce not only carbon dioxide but also methane emissions. Methane gas can be not only a fossil fuel (natural gas) but also a renewable energy source when it is extracted from biomass. After biogas has been purified, its properties become closer to those of natural gas or methane. Natural gas is an alternative energy source that can be used for spark-ignition engines, but its physicochemical properties are different from those of gasoline, and the spark-ignition engine control parameters need to be adjusted. This article presents the results of a study that considers a spark-ignition engine operating at different speeds (2000 rpm, 2500 rpm, and 3000 rpm) and the regulation of the timing of intake valve closure when the throttle is partially open (15%), allowing the engine to maintain the stoichiometric air–fuel mixture and constant spark timing. Studies have shown a reduction in engine break torque when petrol was replaced by natural gas, but break thermal efficiency has increased and specific emissions of pollutants (NOx, HC, CO2 (g/kWh)) have decreased. The analysis of the combustion process by the AVL BOOST program revealed different results when the engine ran on gasoline as opposed to when it ran on natural gas when the timing of intake valve closure changed. The volumetric efficiency of the engine and the speed of the combustion process, which are significant for engine performance due to the different properties of gasoline and natural gas fuels, can be partially offset by adjusting the spark timing and timing of intake valve closure. The effect of intake valve timing on engine fueled by natural gas more noticeable at lower engine speeds when the engine load is low.

Thermal fatigue analysis of different nano coating thickness by air plasma spraying in diesel engine thermal barrier coating

Abstract The use of Atmospheric Plasma Spraying (APS) and yttria stabilized zirconia (YSZ) nanostructured coatings has been applied to the bond layer of NiCrAlY coated engine cylinder heads, pistons, and valve substrates. Thermal barrier coatings (TBCs) have been utilized to increase the engine performance in the design of combustion chamber components for internal combustion engines. ASTM-C-633-01 standard has been employed to conduct the bonding strength testing. It was also considered and directed to estimate the coating’s thermal performance by evaluating its insulation value and conducting a thermal insulation durability assessment. Field emission scanning electron microscope (FESEM) and X-ray diffraction (XRD) were used to look at the nano powders and coatings’ microstructures and phase compositions. In YSZ, it was discovered that the topcoat of samples had a tri-modal pattern of nano sized particles engaged by the powder, micro-columnar grains generated from the re-solidification of the molten part of the powder, and almost equiaxed grains, which were a unique construction feature. The results demonstrated the creation of nano zones in one of three nanostructured coating zones and improved the top coating properties, including bonding strength and thermal insulation capacity. The high temperature of the diesel engine caused fatigue failure in the intake and exhaust valves.

Continuously Variable Valve Mechanism for Spark Ignition Engines Using Linear Actuator

In order to achieve higher performance in spark-ignition engines, it is required to control the intake and exhaust valves in stepless manner according to the engine speed. Our research group has been continuously studying the electromagnetic drive valve system using a linear actuator. In this report, we have designed a linear actuator with a dual Halbach array of permanent magnets in the stator to further increase the thrust of the linear actuator. The thrust characteristics of the proposed model were investigated using electromagnetic field analysis based on the finite element method. The analysis confirmed that the Halbach array concentrates the magnetic flux on the coil side, which generates Lorentz force.

Simulation of turbulent flow in a two-stroke grail engine cylinder

This paper investigates the implementation of computational fluid dynamics for the analysis of a grail internal combustion engine. This is intended to analyse the intake hole and channel shape variables as well as their corresponding influence on the fluid flow properties within the cylinder. Due to the geometry of the engine design which features an intake valve positioned directly on the piston, the combustion efficiency is therefore heavily dependent on the flow characteristics. This necessitates the need to understand and analyse the effects of intake hole and duct geometry as well as piston motion on flow dynamics. A numerical simulation using Autodesk CFD finite element solver was used to simulate the engine flow dynamics of the Grail engine. The results of the analysis show a violent tornado-like effect in the flow field as well as an observable swirl effect characterized by a cylinder-centred single vortex. The resultant flow field obtainable from the design of the Grain engines will therefore allow an ideal homogeneous/stoichiometric fuel-air mixture for increased combustion efficiency. The result of both 3-D static and dynamic simulations of the flow through the engine provided guidelines on the selection of several geometrical parameters for optimal performance. The pressure inside the cylinder of the Grail Engine is validated with the experimental setup. The values of TKE obtained from the numerical simulation are well within the limits obtained from the references.

Influence of Miller cycle on thermal load of high-boosted diesel engine

With the increase of the engine intensified degree, mechanical load and thermal load become to the two main factors limiting the engine to intensify. Application of Miller cycle, which can be realized by late intake valve closing (LIVC) and deeper late intake valve closing (DLIVC), has the potential to reduce the effective CR, mechanical load, and thermal load. In this paper, the effects of LIVC and DLIVC on the mechanical load and thermal load of a boosted DI diesel are experimentally compared. Compared to the original base case, the average cylinder temperature of LIVC and DLIVC is reduced by 90 and 52 K. The exhaust temperature of LIVC and DLIVC decreased by 26 and 14 K, and the maximum combustion pressure of LIVC and DLIVC decreased by 1.6 and 9.7 bar. The pumping losses of LIVC and DLIVC are reduced by more than 25%, while the actual cycle power does not decrease due to the late closing of the inlet valve. The fuel consumption rate decreased from 250.1 g/kWh of base case to 240 g/kWh of LIVC, reduced by 4.0%. The indicated thermal efficiency increased from 41.9% of base case to 43.7% and 42.5% of LIVC and DLIVC. Miller loss is only 2.55% with Miller inlet phase.

Effects of Intake Valve Closure Timing on Heavy-Duty Diesel Engine Performance

Effects of Intake Valve Closure Timing on Heavy-Duty Diesel Engine Performance

Assessment of the Miller cycle operation in a spark ignition engine via 1D numerical simulation

The article presents the results of a 1D numerical simulation of a spark ignition engine developed to operate in Miller cycle. Miller cycle offers better thermal efficiency compared to Otto cycle due to higher volumetric expansion than compression, which in the current context is of paramount importance. In an engine with fixed geometric compression ratio, Miller cycle operation could be realized by means of either early intake valve closing (EIVC) or late intake valve closing (LIVC). Both cases lead however to a lower volumetric efficiency, thus reducing the indicating mean effective pressure, which in its turn results to a lower power output. The simulation’s aim is not only to assess the impact of implementing the Miller cycle but also to obtain the necessary results for imposing the boundary conditions in a 3D CFD simulation whose purpose is to analyse the influence of the Miller cycle on the internal aerodynamics of the engine.

Data-Based In-Cylinder Pressure Model including Cyclic Variations of an RCCI Engine

For advanced pre-mixed combustion concepts, Cylinder Pressure-Based Control is a key concept for robust operation. It also opens the possibility for on-line heat release shaping. For cost and time efficient development of these controllers, fast control-oriented combustion models that predict average in-cylinder pressure traces have been proposed. However, they are not able to capture cyclic variations. In this study, a data-based modelling procedure is proposed to predict the in-cylinder pressure trace and cyclic variation during the combustion cycle. The inputs to the model are the in-cylinder conditions at intake valve closing and the fuelling settings. The proposed model is based on experimental data, Principal Component Analysis and Gaussian Process Regression. This new data-driven approach is applied to model the combustion behaviour of a Reactivity Controlled Compression Ignition engine running on Diesel and E85. The resulting model has a root-square-mean-error of average behaviour and cyclic variance of 0.8° and 0.2°2 in CA50, 0.1bar and 0.03 bar2 in Gross Indicated Mean Effective Pressure, and 0.1% and 0.001 %2 in the Gross Indicated Efficiency, respectively.

Innovative developments of sucker rod pumps to improve the performance of sand producing wells

At the last stage of oil field development, the use of sucker rod pumps is widespread. Due to the drop in formation pressure and other reasons, the inflow of fluid into the well is reduced. The efficiency of the pumps decreases, the pump cylinder is not completely filled. To eliminate these obstacles, a new submersible pump has been developed with a intake valve, which opens and closes with the movement of the balance head. In flooded and sandy wells, sand destroys the working parts of the pump, especially the gap between the plunger-cylinder pair, as a result reduced productivity of the pump. The new pump design allows solving the problem by emulsifying part of the product. The operation of the pump is mathematically justified.

Design and Dynamic Analysis of an Innovative Axial Shift Valvetrain System (ASVS) for Variable Stroke Engine

A variable valvetrain system is the key part of the variable stroke engine (VSE), which could achieve higher power performance and low-speed torque. An innovative axial shift valvetrain system (ASVS) was put forward to meet the air-charging requirements of a 2/4-stroke engine and complete a changeover within one working cycle. Two sets of intake and exhaust cam profiles for both intake and exhaust sides in the 2/4-stoke mode were designed for 2/4-stoke modes. Furthermore, a simulation model based on ADAMS was established to evaluate the dynamic valve motion and the contact force at different engine speeds. The dynamic simulation results show that the valve motion characteristics meet the challenges at the target engine speed of 3000 r/min. In two-stroke mode, the maximum intake valve lift could achieve 7.3 mm within 78°CaA, and the maximum exhaust valve lift could achieve 7.5 within 82°CaA on the exhaust side. In four-stroke mode, the maximum intake valve lift can achieve 8.8 mm within 140°CaA, and the maximum exhaust valve lift can achieve 8.4 mm within 140°CaA. The valve seating speeds are less than 0.3 m/s in both modes, and the fullness coefficients are more than 0.5 and 0.6 in the 2-stroke and 4-stroke mode, respectively. At the engine speed of 3000 r/min, the contact force on each component is acceptable, and the stress between cam and roller can meet the material requirement.

Stochastic Bayesian optimization for predicting borderline knock

Engine knock is an undesirable combustion that could damage the engine mechanically. On the other hand, it is often desired to operate the engine close to its borderline knock limit to optimize combustion efficiency. Traditionally, borderline knock limit is detected by sweeping tests of related control parameters for the worst knock, which is expensive and time consuming, and also, the detected borderline knock limit is often used as a feedforward control without considering its stochastic characteristics without compensating current engine operational condition and type of fuel used. In this paper, stochastic Bayesian optimization method is used to obtain a tradeoff between stochastic knock intensity and fuel economy. The log-nominal distribution of knock intensity signal is converted to Gaussian one using a proposed map to satisfy the assumption for Kriging model development. Both deterministic and stochastic Kriging surrogate models are developed based on test data using the Bayesian iterative optimization process. This study focuses on optimizing two competing objectives, knock intensity and indicated specific fuel consumption using two control parameters: spark and intake valve timings. Test results at two different operation conditions show that the proposed learning algorithm not only reduces required time and cost for predicting knock borderline but also provides control parameters, based on trained surrogate models and the corresponding Pareto front, with the best fuel economy possible.