Hydrogen—An Alternative Fuel for Automotive Diesel Engines Used in Transportation

Considering the current environmental restrictions, particularly those imposed on fossil fuel exploitation, hydrogen stands out as a very promising alternative for the power and transportation sectors. This paper investigates the effects of the employment of hydrogen in a K9K automotive diesel engine. Experiments were conducted at a speed of 2000 min−1 with various engine load levels of 40%, 55%, 70%, and 85%; several quantities were monitored to evaluate the performance with hydrogen use in terms of brake-specific energetic consumption (BSEC), fuel economy, maximum pressure, and heat-release characteristics. It was found that at 55% engine load, the engine efficiency increased by 5.3% with hydrogen addition, achieving a diesel fuel economy of 1.32 kg/h. The rate of increase of the peak pressure and maximum pressure started to increase as a consequence of the higher fuel quantity that burned in the premixed combustion phase, while still remaining within reliable operational limits. The accelerated combustion and augmented heat release rate resulted in a combustion duration that was reduced by 3° CA (crank angle degree), achieving a mass fraction burned percentage of 10% to 90% earlier in the cycle, and the combustion variability was also influenced. Hydrogen use assured the decrease of CO2, HC, NOx, and smoke emission levels in comparison with classic fueling.

Оценка спектральной оптической толщины пламени в камере сгорания судового дизеля

Использование математических моделей, в основу которых положен зональный метод расчета теплообмена излучением, применительно к камере сгорания судового дизеля, требует предварительного определения ряда энергетических характеристик. Важнейшей из них является спектральная оптическая толщина племени. Целью данной статьи является разработка расчетного метода для оценки спектральной оптической толщины пламени в камере сгорания судового дизеля 6 ЧН 24/36. Показано, что величина спектральной оптической толщины пламени зависит от трех основных параметров: коэффициента ослабления излучения, концентрации частиц сажи и их оптических характеристик (среднего диаметра и параметра дифракции). Представлены распределение частиц сажи по размерам и значения спектральной оптической толщины пламени в функции угла поворота коленчатого вала для судового дизеля 6 ЧН 24/36 при испытании его по нагрузочной характеристике. Приведены основные подходы, позволяющие определить интегральную степень черноты пламени в камере сгорания с использованием полученных расчетных данных по его спектральной оптической толщине.Application of mathematical models in the base of them a zonal method of calculation of radiative transfer is included in additional to marine diesel combustion chamber, it is required first determination the number of power data. Spectral optical thickness of flame is very important. Development of method calculation for the estimation of spectral optical thickness of flame in marine diesel 6 ChN 24/36 combustion chamber is the purpose of this paper. A value of spectral optical thickness of flame depends from three basic data: coefficient of attenuation radiation, concentration of soot particles and its optical data (mean diameter and parameter of diffraction) is given. Distribution of soot particles according to sizes and values of spectral optical thickness of flame in function of crank angle degree for marine diesel 6 ChN 24/36 in its power data is shown. Basic methods per missing to determine integral degree of flame blackness in combustion chamber with application of calculation data on its spectral optical thickness is determined.

Real-Time Classification of Diesel Marine Engine Loads Using Machine Learning

An engine control system is responsible for controlling the combustion parameters of an internal combustion engine to increase the efficiency of the engine. An optimized parameter setting of an engine control system is highly influenced by the engine load. Therefore, with a change in engine load, the parameter settings need to be updated for higher engine efficiency. Hence, to optimize parameter settings during operation, engine load information is necessary. In this paper, we propose a real-time engine load classification from sensed signals. For the classification, an artificial neural network is used and trained using processed, real, measured data. To that end, a magnetic pickup sensor extracts the rotational speed of the prime mover of a four-stroke V12 marine diesel engine. The measured signal is then converted into a crank angle degree (CAD) signal that shows the behavior of the combustion strokes of firing cylinders at a particular engine load. The CAD signals are considered an input feature to the designed network for classification of engine loads. For verification, we considered five classes of engine load, and the trained network classifies these classes with an accuracy of 99.4%.

Cylinder-specific model-based control of combustion phasing for multiple-cylinder diesel engines operating with high dilution and boost levels

Accurate control of combustion phasing is indispensable for diesel engines due to the strong impact of combustion timing on efficiency. In this work, a non-linear combustion phasing model is developed and integrated with a cylinder-specific model of intake gas. The combustion phasing model uses a knock integral model, a burn duration model, and a Wiebe function to predict CA50 (the crank angle at which 50% of the mass of fuel has burned). Meanwhile, the intake gas property model predicts the exhaust gas recirculation fraction and the in-cylinder pressure and temperature at intake valve closing for different cylinders. As such, cylinder-to-cylinder variation of the pressure and temperature at intake valves closing is also considered in this model. This combined model is simplified for controller design and validated. Based on these models, two combustion phasing control strategies are explored. The first is an adaptive controller that is designed for closed-loop control and the second is a feedforward model–based control strategy for open-loop control. These two control approaches were tested in simulations for all six cylinders, and the results demonstrate that the CA50 can reach steady-state conditions within 10 cycles. In addition, the steady-state errors are less than ±0.1 crank angle degree with the adaptive control approach and less than ±1.3 crank angle degree with feedforward model–based control. The impact of errors on the control algorithms is also discussed in the article.

Combustion phasing modeling and control for compression ignition engines with high dilution and boost levels

Because fuel efficiency is significantly affected by the timing of combustion in internal combustion engines, accurate control of combustion phasing is critical. In this paper, a nonlinear combustion phasing model is introduced and calibrated, and both a feedforward model–based control strategy and an adaptive model–based control strategy are investigated for combustion phasing control. The combustion phasing model combines a knock integral model, burn duration model, and a Wiebe function to predict the combustion phasing of a diesel engine. This model is simplified to be more suitable for combustion phasing control and is calibrated and validated using simulations and experimental data that include conditions with high exhaust gas recirculation fractions and high boost levels. Based on this model, an adaptive nonlinear model–based controller is designed for closed-loop control, and a feedforward model–based controller is designed for open-loop control. These two control approaches were tested in simulations. The simulation results show that during transient changes, the CA50 (the crank angle at which 50% of the mass of fuel has burned) can reach steady state in no more than five cycles and the steady-state errors are less than ±0.1 crank angle degree for adaptive control and less than ±0.5 crank angle degree for feedforward model–based control.

Determining selected diesel engine combustion descriptors based on the analysis of the coefficient of variation of in-chamber pressure

This paper presents a method that uses the coefficient of variation (COV) of pressure in a diesel engine combustion chamber to determine the crank angle degree (CAD) for which the heat release rate (HRR) reaches the maximum value. The COV was proposed for determining the point corresponding to the angle of start of combustion (SoC). Regression models were fit with these descriptors for the engine powered by diesel, biodiesel or a combination of both, operating under full- or part- load conditions. The uncertainty parameter in these models was determined. Good agreement between the experimental results and the literature data shows the validity of the analysis

Research of Working Mode Conversion Based on GDI Engine

This paper designs the control strategy of working mode conversion from stoichiometric homogeneous mixture to lean homogeneous mixture. First of all, after the types and parameters of electric hardware were selected in this system, a complete circuit layout of engine control system was designed, which used microcontroller named MC9S12XDP512 as control chip and the test bench was built. Then, we adjust the fuel injection pulse width and throttle opening to realize lean burn (lambda = 1.4) of torque being 40N.m at speed of 2500 r / min, and adjust injection timing to find the best injection timing which is 350 crank angle degree, and adjust the ignition advance angle to find the best ignition advance angle which is 13 crank angle degree. Finally, the work mode conversion was completed by the optimal parameters linear interpolation, reducing the fuel injection pulse width and increasing the throttle opening at the same time.

Turbulence Measurements Within a Cyclic Flow and Analysis in the Momentum Equation

Particle Image Velocimetry (PIV) measurements were performed within an optical water analog engine. A unique triggering and data collection system was developed to allow a CCD camera to acquire two consecutive image frames at predetermined crank angles. The water analog engine operated at 15 RPM and had a square cross-section with two circular valved inlets. Measurements were made throughout an entire cycle to determine mean and turbulence statistics and results at 60 crank angle degree are discussed in this paper. Different averaging techniques were used and results between the techniques were compared to provide a number of statistical quantities having large discrepancies in scales and distributions. A study of the equations of motion showed that different averaging techniques results in differing physical interpretations of the flow.