Abstract. Modern electric automobiles tend to have greater battery capacities. Battery packs with an average capacity of 16-22 kWh were used at the initial stage of manufacturing serial electric vehicles. A number of new models of electric vehicles are equipped with batteries, the capacity of which exceeds 30 kWh, which can result in a significant increase in the basic weight of the electric vehicle. Any increase in the weight can lead to an increase in energy consumption per km travelled. The present research developed a methodology for determining the range and dynamic parameters of electric vehicles depending on changes in the basic weight of the vehicles. The present research also calculated the effect of changes in the weight for various serial electric automobiles.Keywords: battery weight, electric automobile range, battery capacity, energy consumption, electric automobile dynamics. IntroductionDue to the need to reduce CO 2 emissions, the EU's climate protection programmes introduce support for alternative energy vehicles and related infrastructure. Electric automobiles are one of the kinds of alternative energy vehicles. Even though the first electric automobiles emerged along with internal combustion vehicles, i.e. more than 110 years ago, the electric automobiles have not become popular. The key reason that prevented electric automobiles from being broadly introduced was their heavy batteries and the relatively limited autonomy per charge. The reason of their relatively limited autonomy was the relatively low density of energy stored in the batteries, compared with the amount of energy available in liquid fuel. Electric automobiles were referred to many times during the evolution of auto transport, yet they were usually manufactured in small experimental series and were mainly custom-made.First hybrid technology automobiles were introduced at the beginning of the 21 st century, and later electric automobiles appeared as well. However, the key disadvantage of electric automobiles, just like it was 110 years ago, was the relatively heavy battery packs that did not allow considerably increasing the travel range of the electric automobiles. A lot of funds were invested in the fields of science related to the development of battery technologies for electric automobiles; however, at present, no very light and cheap batteries that, in terms of the weight and energy capacity, are equivalent to the fuel tank of internal combustion automobiles have been designed. For this reason, the buyers of electric automobiles need to choose the automobiles meeting the necessary operational conditions, one of which is the travel range per charge. An essential aspect in purchasing an electric automobile is the price of it [1].Research on the effects of the weight of batteries of an electric automobile and of the total weight of the electric automobile on its performance parameters is very urgent. In designing a greater capacity fuel tank for an internal combustion engine automobile, auto manufacturers only risk decreasing the...

When converting an internal combustion vehicle to electric power, it is important to choose the right transmission gear ratio to ensure optimum performance of the vehicle. A converted automobile is usually equipped with a standard transmission gearbox, while the motor control block is programmed for one particular gear. During the operation of an electric automobile, the gears could be shifted, when the automobile is stopped, as the clutch is not used by the electric automobile. In choosing a gear ratio, a priority could be to ensure good dynamic performance or high speed achievement. However, one of the most important parameters is energy consumption and the distance covered per charge. After identifying the optimum gear ratio or the gear to be used, the unused gears of the transmission gearbox of the converted vehicle could be dismantled, thereby reducing the weight of the vehicle and increasing the transmission gear ratio. A converted Renault Clio with a 96 V battery system and a standard 5-speed transmission gearbox was road tested. The experimental dataspeed, change in voltage and current, battery temperature and measurement time were recorded by a multichannel data logger. The road tests were carried out at constant speeds-50 and 90 km•h-1. The road tests showed that energy consumption by the electric automobile in the fourth gear at 50 km•h-1 was the lowest, consuming a power of 5.86 kW, while in the fourth gear at 90 km•h-1 it consumed 15.43 kW.

As the use of fossil energy sources in transport declines, new technologies, e.g., electric vehicles, are being introduced. One of the advantages of electric vehicles in urban driving is the possibility to charge their batteries with regenerative energy during braking. For this reason, electric cars usually have a longer range per charge in urban driving than in non-urban driving. This research experimentally examined the regenerative braking of a converted Renault Clio electric car at different regenerative braking settings in the range of 0–100%. An original research methodology was developed for road tests in urban driving. The driving cycle included aggressive driving with rapid acceleration and braking. The road test was conducted in second and third gears, which are the usual gears for driving an electric car in a city. The highest regenerative braking efficiencies were achieved at a 100% setting, which in some replications reached 24% of the total electrical energy consumed; however, the 100% setting was too high from the perspective of comfortable driving of the electric car and contributed to a too significant increase in the braking force at the initial stages of braking.

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An analysis of the grain industry in Latvia reveals that crop yields and the cropped area tended to increase in recent years. The most popular crops grown were wheat, barley and rapeseed. The research aim is to examine the characteristics of services provided by a grain pre-processing complex in the Latvian market based on the example of Amazone Ltd. The research compared the requirements of customers against the characteristics of grain pre-processing services by using a quality function deployment matrix, and direct competitors were compared by means of the point method. Grain pre-processing is a very specific industry; for this reason, experience and a workforce of high quality play an essential role in competing with market leaders.

In the last decade, alternative energy is being used in various vehicles due to the depletion of fossil energy resources. One of the kinds of alternative energy is electricity. Electric drive can be used in land vehicles, aircraft and watercraft. To identify the possibility of using electric watercraft and the technical parameters, an experiment was conducted in real navigation conditions in the territory of Jelgava city on the Driksa canal on a 1.62 km long route. The experiment used a data logger to take measurements of parameters of the motor and the solar cell, as well as of solar intensity. The experiment was done with a rebuilt pedal-powered catamaran equipped with a 445 W solar panel, a 40 Ah lithium-ion battery and a Minn Kota Endura C2 34 electric motor. The experimental data were processed to identify the power and energy generated and consumed parameters for the electric motor, the solar panel and the battery of the watercraft. On the day of the experiment at a solar intensity of 500-600 W·m-2, the catamaran could cover an unlimited distance at power settings 3 to 5 at a speed of 2.73 km h-1 to 3.79 km h-1. At power setting 5, the electric motor consumed a power input of 320-330 W – a power output generated by the solar cell in sunny weather. If the battery is discharged, the solar cell charges it when the watercraft is anchored in the port, as well as when moving in case the solar cell generates more energy than the motor consumes at a particular power setting. According to the results of the experiment, low-speed electric-drive watercraft equipped with solar cells can be operated without additional battery charging at all power settings at geographical latitudes up to 57° and solar altitudes up to 35°-56°.

In order to ensure the development and competitiveness of an organization, it is essential to continuously enhance processes, particularly those that generate revenue, i.e. business processes, as well as to introduce innovations. One of the business processes at BBS-Dizain Ltd that needs to be enhanced is the catering service. The aim of the research is to examine possibilities for shortening order processing times at BBS-Dizain Ltd. The research concluded that the average rating of order processing time at the restaurant given by the employees of BBS-Dizain Ltd (internal customers) was higher (4 points) than the rating given by visitors (external customers) (3.49 points). A contingency analysis showed that there was no correlation between the ratings given by external and internal customers; therefore, the restaurant’s personnel did not critically assess their performance in terms of order processing time. Since changes in the demand for the dishes on the menu of the restaurant exceeded 25%, and none of the dishes on the menu was a leader in terms of revenue generated, there were no dishes, the cooking process of which BBS-Dizain Ltd needed to optimize. The chefs of BBS-Dizain Ltd could enhance their skills in preparing Group AY meals, as the demand for them was relatively steady. Rearranging the workplace of a chef, using the 5S methodology, and replacing the worktop for the chef with a freezer allows significantly – two-fold – reducing the number of the steps made during the shift. However, rearranging the restaurant’s storeroom, using the 5S methodology, allows saving 95 % time spent on searching for things needed. Therefore, the possibilities to reduce order processing times at the restaurant of BBS-Dizain Ltd involve decreasing unnecessary movements of chefs at their workplaces and reducing the time spent on searching for things in the storeroom.