The Effects of Backpressure on the Performance of Internal Combustion Engine and Automobile Exhaust Thermoelectric Generator

The maximum generated power of automobile exhaust thermoelectric generator (AETEG) can be enhanced by applying inserted fins to its heat exchanger, for the temperature difference of thermoelectric modules (TEMs) is increased. However, the heat exchanger will result in undesired backpressure, which may deteriorate the performance of the internal combustion engine (ICE). To evaluate the backpressure on the performance of both the ICE and the AETEG, the model of ICE integrated with AETEG was established with the GT-power software and validated with the AETEG test bench. The heat exchangers with chaos shape and fishbone shape were proposed, their pressure drop with different engine speeds was studied, and their effects on the performance of both the AETEG and the ICE were analyzed. The results showed that compared with the fishbone-shaped structure, the pressure drop of chaos-shaped heat exchanger is larger at the same engine speed, which contributes to the increased maximum power and hot side temperature of the AETEG. Moreover, compared with the ICE without heat exchanger, the brake torque, brake power, volumetric efficiency and pumping mean effective pressure of the ICE assembled with chaos-shape and fishbone-shape heat exchanger reduce, and the corresponding brake specific fuel consumption, CO emission and CO2 emission increase because of the raised backpressure caused by the heat exchanger.

GAS DISTRIBUTION PHASES HYDRAULIC CONTROLLED INTERNAL COMBUSTION ENGINE VALVES

The efficiency of an agricultural car or tractor depends on the characteristics of the engine determined by the gas distribution mechanism (GRM). Traditional timing with fixed valve timing does not provide high-quality gas exchange at all engine operating modes. The aim of the work is to improve the characteristics of the engine by using the hydraulic drive of the timing valves. The drive allows you to turn off individual valves, set the moments of their opening and closing in an arbitrary way, provide several triggering of the internal combustion engine valves during the operating cycle. The drive is controlled by an electronic control unit (ECU). The advantage of the drive is its ease of integration into the internal combustion engine. The hydraulic drive ensures that the timing valves are lifted to a height of about 14 mm. The law of displacement of the valve, revealed experimentally, is close to trapezoidal. The use of a hydraulic valve drive has a positive effect on the "time-section" factor in the area of low and medium crankshaft rotational speeds. The increment of the factor "time-section" is due to the significant speeds of opening and closing the valves. Due to the peculiarities of the kinematic characteristics of the movement of the valves when using a hydraulic drive for their movement, the use of serial phases of gas distribution of the engine is impractical. Numerical modeling of the operation of the internal combustion engine determined the regularity of the change in valve timing from the high-speed operating mode of the engine. Optimization criterion is the achievement of maximum engine power. When choosing the valve timing, the possibility of meeting the intake and exhaust valves with the engine piston was excluded. The use of optimal phases leads to an increase in power up to 4.5% at a low crankshaft speed. With an increase in the speed mode, the increase in power decreases, and with a high frequency of rotation of the crankshaft, its slight decrease (1.4%) is observed. An increase in torque, up to a power utilization factor of 0.9, and its subsequent decrease, allow stabilizing the vehicle speed on a road with variable resistance. An increase in the working pressure in the hydraulic drive of the valves makes it possible to intensify gas exchange even at a high speed of rotation of the crankshaft

Ducted Wind Turbine in Generating Set Air Flow

The growing need to use renewable sources and the current difficulty in spreading the electricity grid in a widespread manner raise the question of how to respond to the need for more electricity immediately. The idea behind this study is to power a horizontal axis wind turbine with the air flow generated for cooling a stationary internal combustion engine. The power extracted from this solution is significantly lower than that of the internal combustion engine (about 0.3%) and could be advantageous only in limited contexts. Installation costs are limited because many elements deriving from wind variability can be removed or simplified.

Automation of an automobile internal combustion engine bench calibration tests

Introduction (problem statement and relevance). The article presents the work on the automation of an internal combustion engine (ICE) calibration tests results on a motor stand. The relevance of the article is due to the high labor intensity of such tests, the complexity of documentation and decisionmaking based on the results of the work.Purpose of the study. This work is part of a comprehensive methodology, the purpose of which is to reduce the duration of tests and improve the calibration results quality of the vehicle’s power plant. The entire methodology description as a whole is also given in the publication.Methodology and research methods. The achievement of this goal is ensured with the help of special systems – INCA-FLOW (test automation) and ASCMO (processing results and optimization), produced by Bosch/ETAS. The approbation of the technique was carried out on a motor stand in the MADI training box in relation to the problem of forming an ignition timing map.Scientific novelty and results. As a result of the methodology application, a 4.8 times reduction in the motor tests duration takes place if 2 people work in manual mode at the test bench without interruption.At the same time, the variance of the adequacy of Sad of the torque empirical model Mk turned out to be, on average, 1.5 times less if the model was built according to the automated tests results. The obtained data indicated an improvement in the quality of measurements in the transition to automated test methods.From a scientific point of view, the most original part of the work is the application of the “Gaussian process” method to build empirical models. This method provides more accurate results than, for example, the traditional method of least squares.The practical significance of the work lies in the ability to considerably reduce routine actions on a motor stand, and the additional time spent on developing and testing a test scenario (program) is compensated for by the fact that scenario models can be used in the future for other similar tests. The proposed methodology makes it possible to cover a significant part of the internal combustion engine calibration tests. For example, you can apply it if you possess the preliminary information about the test object (basing on which you can draw up an experiment plan) and the engine is to be prepared either for a car road tests or tests under special conditions.

Experimental study of an internal combustion engine fueled by a low-calorific value producer gas

This paper describes an experimental study of the operation of an internal combustion engine of fueled by a low-calorific value gas. The main operating parameters of low-power ICE were determined. Efficiency was also evaluated when the ICE was converted to operate on producer gas. In the experiment, it was shown that the engine reached a stable operating mode under load and data on the temperature and exhaust gases composition were obtained. According to our estimates, in the steady-state operation of the internal combustion engine with a load, the efficiency factor was about 22 %. When using the model gas, the from generator output power, was about 30-40 % of the nominal value, under variable load conditions. However, it was found that in steady-state operation, the power of the internal combustion engine was 40-55% of the nominal value.

The Costs of Charging Electric Vehicles in Poland

The very important factor that influences the decision of those interested in buying a vehicle is its operating costs. This paper determines the costs of driving 100km for various electric vehicles, charging service providers and chargers, which was then confronted with the costs of refueling. Based on the analysis carried out, it was determined that, at present, the lowest costs of fueling/charging of a vehicle in Poland are connected with use of an electric vehicle, but only when the charging is performed with use of public AC chargers. Moreover, it was determined that the savings that will result from charging electric vehicles at AC charging stations as compared to filling up internal combustion engine vehicles are small and do not compensate for the purchase price of an electric vehicle.