Optimization methods play a key role in the design and control of modern powertrains in the current automotive industry. Emphasis is placed primarily on the implementation of optimization algorithms and predictive models that are used by engine control units. These are intended to ensure effective control of torque, fuel consumption and vehicle dynamics in real time depending on driving conditions and driver requirements. The aim of the paper was therefore to describe the results of research conducted in the field of multi-parametric optimization of fuel consumption and performance of a four-cylinder atmospheric internal combustion engine with a cylinder capacity of 1,390 cm3. Optimization of the operating parameters of the powertrain, such as fuel consumption and performance, was carried out with a view to the possibility of implementation into control algorithms and predictive models applicable to engine control units. The benefit of the proposed optimal operating mode of the powertrain, aimed at minimizing fuel consumption and maximizing its output power, is the achievement of high operating efficiency while maintaining favorable dynamic characteristics of the engine.
This paper investigates the relationship between the physical properties of a controlled dynamic system and the optimal configuration of hyperparameters in the multi-objective evolutionary algorithm NSGA-II (Non-dominated Sorting Genetic Algorithm II). The aim is to determine whether, and to what extent, the optimal hyperparameter settings of NSGA-II change in response to physical modifications of the system. The test model is a rotary inverted pendulum, whose physical characteristics are altered by shifting the position of its center of mass. For each tested center-of-mass position, NSGA-II generates a Pareto front of optimal settings of a linear quadratic regulator with respect to maximum overshoot and settling time of the controlled system. The search for optimal hyperparameters for each configuration is performed using Bayesian optimization. Experimental results show that some hyperparameters exhibit weak dependence on the physical changes in the model, while others remain stable. These findings may serve as a basis for establishing general guidelines for effective tuning of evolutionary algorithms depending on the characteristics of the controlled dynamic system.
Optimization methods play a key role in the design and control of modern powertrains in the current automotive industry. Emphasis is placed primarily on the implementation of optimization algorithms and predictive models that are used by engine control units. These are intended to ensure effective control of torque, fuel consumption and vehicle dynamics in real time depending on driving conditions and driver requirements. The aim of the paper was therefore to describe the results of research conducted in the field of multi-parametric optimization of fuel consumption and performance of a four-cylinder atmospheric internal combustion engine with a cylinder capacity of 1,390 cm3. Optimization of the operating parameters of the powertrain, such as fuel consumption and performance, was carried out with a view to the possibility of implementation into control algorithms and predictive models applicable to engine control units. The benefit of the proposed optimal operating mode of the powertrain, aimed at minimizing fuel consumption and maximizing its output power, is the achievement of high operating efficiency while maintaining favorable dynamic characteristics of the engine.
The aim of the research is to assess the energy efficiency of proposed heat, electricity and hot water supply systems for apartment buildings. Schematic solutions of heat and power generating units based on liquid-vapor jet devices. The proposed schemes are improved solutions for mini-TPP and heat pump unit, and fundamentally new decisions have been developed, the so-called combined scheme of heat-&-electricity power generating aggregate, which has all the advantages of the previous two schemes. For the studied building, the parameters determining the heating system operation were previously determined, including hot water consumption based on the number of residents and electricity consumption defining the required turbine power. To determine feasibility of using heat-&-electricity power generating aggregate based on liquid-vapor jet devices, thermodynamic, exergetic and thermoeconomic analyses were performed. As a result of thermodynamic analysis, the load and power of devices included in proposed scheme solutions were determined, as well as the values of the main material flows participating in the energy conversion process in the proposed schemes. As a result of the exergetic analysis, the efficiency of the proposed schemes was determined. The most effective was the combined scheme, which is 23% better than the heat pump unit and 11% better than the mini-TPP. According to the results of the thermoeconomic analysis, the tariffs at which residents will receive heat, hot water and electricity were determined and compared with the current state ones. The combined scheme turned out to be the best. For it, the tariffs are on average 32-35% lower than the state ones for civil consumers.
The work establishes a number of features regarding the mechanics of freezing wet quartz sands when manufacturing products of limited sizes from them. Products of limited sizes from frozen sand in foundry production are casting models used for manufacturing volumetrically closed and detachable casting molds using the SMS-process method, frozen casting molds and rods, etc. The work used quarry quartz sand of the 1K2O202 brand and tap water. The mass was measured on a VTA-60/6-73-AL-2 scale with an accuracy of +/- 1 g. The temperature was measured with an alcohol thermometer of the TTZ type and a chromel-copel thermocouple complete with an electronic device of the STC-1000 brand with an accuracy of +/- 1 degrees & Scy; with video recording of temperature changes over time with an interval of 1 s. Drying of sand was carried out in a microwave oven with a magnetron power of 900 W and a microwave radiation frequency of 2.45 MHz. Freezing of wet sand was carried out in a refrigeration chamber with a capacity of 17 kg/day at a temperature of-20 degrees C. According to the results of the research, it was found that flat products with a thickness of 10 mm, regardless of the water content (up to 12.5% above), under conditions of unidirectional heat removal, cool to 0 degrees C faster than dry quartz sand. Freezing of wet sand under conditions of multidirectional heat removal from it leads to a significant migration of water in the sand in the direction of gravity, i.e. from the solidification front of wet sand to a surface with a higher temperature, which is in the direction of movement of unfrozen water. Increasing the initial temperature of wet sand contributes to an increase in the rate of its cooling to 0 degrees C and the time of solidification of water, but increases the total time of solidification of wet sand.
