Car engine diagnostics using a vacuum gauge

<div class="htmlview paragraph">In addition to first test results from a one single-cylinder engine with the UniValve fully variable valve lift and timing system - presented at the 2005 SAE Congress - this paper contains the results of a fired 2.0 I four cylinder gasoline engine <b>[<span class="xref">1</span>]</b>, <b>[<span class="xref">2</span>]</b>. The cylinder head has been replaced with a new cylinder head concept that includes the fully variable valve lift and timing system (VVTL system) UniValve. The other engines parameters and components have not been changed. The intention was to investigate the engine behavior only by exchanging the standard inlet valve train with for the UniValve fully variable valve train. The VVT engine load can be controlled either with a standard throttle or unthrottled, only through the fully variable variation of the valve lift and the valve opening period. The engine has been installed on a dynamic test bench. The torque behavior, the power output, the raw emissions and the fuel consumption have been measured for the standard series production engine directly in comparison with the VVT engine. The VVT engine was driven with both load control options. With different valve lift heights of two adjacent inlet valves the flow turbulence can be increased. This influence of this inlet valve phasing on the fuel consumption and on the emissions at part load will be measured on the UniValve engine too in 2006 too. With a special design of the turnable eccentric control shaft the engine can be driven with different loads for defined cylinder groups, so that for example for a specific engine load point a cylinder group runs with low load while the other cylinder group works with higher load. This load control strategy is called “Cylinder Up Loading”. The target therefore is to get still a higher efficiency and a better fuel consumption at higher part loads.</div>

<div class="section abstract"><div class="htmlview paragraph">Diesel engine is vital in the industry for its characteristics of low fuel consumption, high-torque, reliability, and durability. Existing diesel engine technology has reached the upper limit. It is difficult to break through the fuel consumption and emission of diesel engines. VVA (Variable Valve Actuation) is a new technology in the field of the diesel engines. In this paper, GT-Suite and ANN (artificial neural network) model are established based on engine experimental data and DoE simulation results. By inputting Intake Valve Opening crake angle (IVO), Intake Valve Angle Multiplier (IVAM) and Exhaust Valve Angle Multiplier (EVAM) into the ANN Model, and by using SA (simulated annealing algorithm), the optimized results of intake and exhaust valve lift under the target conditions are obtained. According to the optimized results, the fuel consumption of BSFC (brake specific fuel consumption) can be saved by 3.9%, 0.9%, and 7.3% at three different target working conditions, respectively (1000r/min with 50% load, 2000 r/min with 35% load, and 3000r/min with 20% load. Under the three conditions, the intake valve lifts are 1.10, 0.96, 1.10 times as the original respectively and the exhaust valve lifts are 0.98,0.94 and 1.10 times respectively. In addition, by adding the secondary opening strategy of the exhaust valve lift, internal exhaust gas recycling (IEGR) can be achieved. The exhaust gas temperature increased by 9.55% (66.64K) under low-speed working condition, and fuel consumption increased slightly by 6.15%, which is also important for exhaust thermal management and external emission control in the cold start phase of diesel engines. By changing the intake and exhaust valve control, there are obvious differences in the optimal valve lift under different working conditions. Therefore, the application of the VVA system in the diesel engine is of great significance.</div></div>

Emissions from gasoline and diesel engines vary on time scales including diurnal, weekly, and decadal. Temporal patterns differ for these two engine types that are used predominantly for passenger travel and goods movement, respectively. Rapid growth in diesel fuel use and decreasing NOx emission rates from gasoline engines have led to altered emission profiles. During the 1990s, on-road use of diesel fuel grew 3 times faster than gasoline. Over the same time period, the NOx emission rate from gasoline engines in California was reduced by a factor of approximately 2, while the NOx emission rate from diesel engines decreased only slightly. Diesel engines therefore grew in both relative and absolute terms as a source of NOx, accounting for about half of all on-road NO, emissions as of 2000. Diesel truck emissions decrease by 60-80% on weekends. Counterintuitive responses to these emission changes are seen in measured concentrations of ozone. In contrast, elemental carbon (EC) concentrations decrease on weekends as expected. Weekly and diurnal patterns in diesel truck activity contribute to variability in the ratio of organic carbon (OC) to EC in primary source emissions, and this could be a source of bias in assessments of the importance of secondary organic aerosol.

<div class="section abstract"><div class="htmlview paragraph">As the efforts to push capabilities of current engine hardware to their durability limits increases, more accurate and reliable analysis is necessary to ensure that designs are robust. This paper evaluates a method of Conjugate Heat Transfer (CHT) analysis for a gasoline and a diesel engine that combines combustion Computational Fluid Dynamics (CFD), engine Finite Element Analysis (FEA), and cooling jacket CFD with the goal of obtaining more accurate temperature distribution and heat loss predictions in an engine compared to standard de-coupled CFD and FEA analysis methods. This novel CHT technique was successfully applied to a 2.5 liter GM LHU gasoline engine at 3000 rpm and a 15.0 liter Cummins ISX heavy duty diesel engine operating at 1250 rpm. Combustion CFD simulations results for the gasoline and diesel engines are validated with the experimental data for cylinder pressure and heat release rate. Radiation models were implemented to estimate heat transfer more accurately for diesel engine. FEA simulations are performed in a separate software platform. Data exchanges between CFD and FEA software codes are performed at specified sub-cycle engine intervals and the simulations are continued for multiple engine cycles until cycle-to-cycle convergence of wall temperatures is achieved. The model predictions are validated against experimental data available from thermocouples embedded inside the cylinder head. The detailed CHT model includes the coolant circuit and oil gallery. The overall predictions from the model match closely with the experimental observations. The work establishes a validated modeling framework for CHT modeling in gasoline and diesel engines.</div></div>

<div class="htmlview paragraph">This paper presents a broad review of the whole subject of variable valve timing applied to both gasoline and diesel engines, including related technology such as the use of supplementary valves in the intake ports or manifolds. The current motivation to provide variable valve timing and the state of development of mechanisms to achieve it are discussed, followed by a prediction of possible future trends.</div>

<div class="htmlview paragraph">The paper presents an original review and extension of existing mathematical models for on-line residual gas fraction estimation. The resulting model has first of all been extended to take into account also the presence of externally recirculated exhaust gas (external EGR), and then critically analyzed to highlight the importance of a correct Intake Valve Opening and Exhaust Valve Closing effective position identification. As shown in the paper, such quantities may be evaluated by using experimental data, either acquired in the test-cell or on a valve flow bench.</div> <div class="htmlview paragraph">The main objective is to obtain a simple and reliable model (that could be run in real time within the engine control unit) also in presence of Variable Valve Timing (VVT, both on intake and exhaust valves) and external Exhaust Gas Recirculation (EGR) systems. In fact, the two main contributions to residual gas fraction (backflow of the burned gas during the valve overlap period, and amount of gas trapped within the cylinder) are strongly affected by intake and exhaust valves timing, and EGR flow should be taken into account in order to determine the total exhaust gas mass within the cylinder at IVC. Therefore, real time estimation of residual gas mass and composition is crucial for designing VVT and EGR management strategies that allow an optimal control of the combustion process.</div> <div class="htmlview paragraph">The new model has been applied to experimental data acquired on a 3.2 liter V6 GDI engine, equipped with intake and exhaust Variable Valve Timing systems. Tests were performed throughout the engine operating range for different combinations of intake and exhaust valve timings, while varying EGR flow. Model results are in good agreement with other measured quantities (such as Spark Advance angle and NO<sub>x</sub> emissions), and the proposed approach therefore represents a powerful tool for on-board optimal combustion control.</div>

Blending of ethanol with gasoline and diesel fuel – A review

Over the past two decades considerable effort has been taken to develop and introduce new alternate source of energy for the conventional gasoline and diesel. Environmental pollution and uncertainty in cost of petroleum products are the principal driving forces for this movement. The major pollutants from an Diesel engine system are NOx, Smoke, particulate matter, Soot. Several alternative fuels were tried but all of them are carbon based fuels, therefore net carbon based pollutants cannot be reduced. One alternative to carbon-based fuels is hydrogen. Hydrogen a non-carbon fuel only can meet zero emission vehicles standards in future. Hydrogen can be commercially used as a fuel even though it is having a number of technical and economical barriers. Numerous techniques are available for use in C.I. engine such as dual fuel made, by using spark plug, glow plug, DEE as an ignition enhancer. Hydrogen was used in a diesel engine in the dual fuel mode-using diesel as an ignition source in neat form using DEE. In neat form the DEE was introduced in the manifold. In order to have a precise control of hydrogen flow and to avoid the backfire and pre – ignition problems hydrogen was injection in to intake manifold; DEE injection follows the hydrogen injection. DEE mixed with air and flows into the combustion chamber as DEE auto ignites first followed by hydrogen combustion. A single cylinder-four stroke water-cooled naturally aspirated constant speed D.I. diesel engine with a rated output of 3.7 kW at 1500 rpm was used for the experimental purpose. Measurements were taken with respect to the performance, combustion and emission studies.

Compression ignition diesel engines are the most promising source of power for many stationary and commercial vehicles. The performance of the diesel engine could be improved by the optimum design of the combustion chamber, induction system and exhaust system. In the case of diesel engines, airflow inside the engine cylinder has a considerable influence on the combustion and emission levels of the engine. In this research work, engine performance investigations are carried out by improving air swirl motion by applying guide vanes inside the intake manifold. The effect of guide vane on airflow inside the cylinder is studied by using 3D internal combustion engine simulation software under motored engine conditions with the help of ANSYS-CFX. A single-cylinder diesel engine is modelled to analyse the effect of the design and geometry of guide vane on airflow inside the cylinder. The guide vanes are designed to incorporate into intake pipe of the engine in different geometries. The number of guide vanes and angle of inclination is configured on the basis of simulation. The simulation result shows that the four guide vanes with 180° helix improve in-cylinder airflow characteristics like pressure, velocity and turbulent kinetic energy. The optimized guide vane intake manifold was designed and tested on the designed experimental test set-up. The experimental results show that the swirl ratio is improved from 0.8 for the base model to 1.35 for the modified manifold model. The engine also tested on a test bench with an basic engine intake system and modified intake manifold. The results show that the modified intake manifold reduces specific fuel consumption by 1% and CO and HC emission by 20%.

Globally, many researchers have been trying to improve the fuel economy of a vehicle for satisfying future <TEX>$CO_2$</TEX> regulation and minimizing air pollution problem. For the same background, diesel engine and vehicle system optimization using simulation models have been key technologies for the improvement of vehicle system efficiency. Therefore, in this study, calibration method for the air breathing system of a WGT diesel engine using mean value model has been composed for efficient engine and vehicle optimization simulation researches. And virtual WGT performances have been calculated for a 2 cylinder downsized diesel engine system. From these researches, the calibration method for the boost pressure and EGR rate of a virtual diesel engine related with WGT performances could be composed and some of technical issue related with downsized diesel engine could be investigated.

디젤엔진은 바이오연료 적용을 위한 엔진으로서 가솔린엔진과 비교해 사용연료가 바이오연료와 유사한 높은 세탄가를 가지며, 가솔린엔진과 달리 점화계통 장치의 불필요 등 기존 엔진의 개조비용 등에서 유리한 장점이 있다. 따라서 본 연구에서는 상용 디젤 엔진의 커먼레일 분사시스템을 사용하여 바이오연료인 식물성 팜유의 분무거동특성을 해석하고, 그 결과를 기존의 디젤엔진 연료인 경유와 비교?분석하였다. 실험변수로서는 분사압력과 경유에 대한 바이오디젤 연료의 혼합비율(BD3, BD5, BD20, BD30, BD50, BD100)을 달리하였다. 분사압력은 500bar, 1000bar, 1500bar 및 1600bar로 설정하고 분사기간은 500μs로 동일하게 하였다. 본 연구의 결과로서, 분사압력이 동일한 경우 사용한 바이오디젤 연료의 혼합비 변화에 대한 거시적 분무거동특성(분무선단도달거리 및 분무각)의 변화는 뚜렷하지 않았다. 특히 분무각의 경우 본 연구의 모든 실험조건에 있어서 약 15°의 값을 나타내었다.

The aim of this study was to develop a diagnostic algorithm for assessing the technical condition of the lubrication system in KAMAZ diesel engines based on the analysis of used oil parameters. Experimental measurements were conducted to determine discrepancies between the actual and permissible (according to technical documentation) oil levels, as well as statistical calculations to evaluate the diagnostic value of specific parameters. The findings revealed that the maximum permissible oil volume in the KAMAZ-740 engine exceeds the nominal level by 30%, and in the KAMAZ-EURO engine by 24%. Statistical analysis identified the most informative diagnostic parameters as oil volume, viscosity, total base number, and flash point. Using the permissible values of the identified indicators, schematic plots were developed, each reflecting the current oil condition and enabling the identification of complex and combined faults. The results led to the development of a diagnostic algorithm for diesel engine lubrication system evaluation and a finite state machine method to predict critical oil levels and prevent typical problems and critical engine breakdowns. The projected annual economic benefit from implementing the developed diagnostic system amounted to USD 144,000 for a fleet of 2000 vehicles, based on an average annual mileage of 60,000 km.

A hybrid disturbance rejection control solution for variable valve timing system of gasoline engines

Modern cars operate in various climatic conditions and have a number of problems, one of which is fuel overheating at elevated ambient temperatures. This article is devoted to solving the problem of improving the reliability of the fuel supply system of a high-speed diesel engine by controlling the temperature of the fuel. Keywords: cooling, power supply system, heat exchanger, fuel equipment

The steady and reliable operation of a ship’s diesel engine is important to the ship’s electrical power system and the engine’s performance, and stable control of rotational speed is crucial to a diesel engine’s emission, economy and power performance. A ship’s diesel engine is a nonlinear and time-varying system. A traditional proportional–integral–derivative (PID) controller cannot regulate the speed under different working conditions. In this paper, a nonlinear mathematical model for speed regulation of diesel engines is established according to experiments and a multi-sliding surface variable structure controller for speed regulation of diesel engine is established by sliding mode control. A bulk cargo ship 500-I was analysed as an example. The MATLAB/Simulink simulation took the navigation environment and the effect of the ship propeller on the diesel engine into consideration. A simulation model considering the whole ship–engine–propeller system is built and some conclusions can be drawn from the simulation. The multi-sliding surface control can restrain the overshoot and realize a quick track of the targeted value with high accuracy and strong robustness. In addition, the fuel consumption and CO2 emission of this sliding mode variable structure control is reduced by 4.6% compared with traditional PID control.