Ukrainian Journal of Mechanical Engineering and Materials Science

Permanent URI for this communityhttps://ena.lpnu.ua/handle/ntb/31565

Browse

Subject: search.filters.subject.car

Search Results

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Influence of the ignition system parameters on the ecological indicators of the automobile gas-fueled engine
    (Видавництво Львівської політехніки, 2019-03-20) Brytkovskyi, Vasyl; Kachmar, Roman; Lanets, Olena; Lviv Polytechnic National University
    The structure of the automobile service, since the beginning of the independence of Ukraine, has changed acutely. The number of private vehicles, the quality of service of which depends on the owner only, has increased. In addition to already existing automobile transport enterprises which has at least some existing production facilities with available cars of post-Soviet production and Russian cars of the middle time of Ukraine's independence, a large number of private small motor vehicles companies without any production base have appeared (in the best occasion with the available storage area), technical condition of the movable composition of which does not meet the requirements of European countries and the main transporting direction of these enterprises was concentrated in the directions of post-Soviet countries. In order to maximize efficiency, the owners of such vehicles carry out the transformation of power supplies to the system supplied with gas fuel. Despite the sufficient number of advantages, such refurbishment requires the introduction of constructive modifications and adjustments also in the ignition system of motor vehicles. And here, in the absence of systematic state control, many of the car owners in pursuit of maximum economy, trying not to make changes, causing violations in the work of car systems, which leads not only to the growth of fuel consumption and reducing of the effective performance of the engine, but also to increasing of emission of toxic components with the exhaust gas flow of the car engines. In conditions of Ukrainian cities, where emissions of toxic components by transport sources are up to 90% of all harmful effects [11], the search for ways to improve the system of technical service of vehicles is relevant in order to control and reduce the level of environmental hazards from the operation of vehicles. Therefore, researches that focus on determining the influence of regulation of the ignition system of engines powered by gas fuel, on the example of the spark plug gap influence on the indicators of the content of the components of the exhaust gases, are relevant. The method of research on the influence of the spark plug gap on the change in the composition of exhaust gases was developed in the paper, the research was carried out on ZAZ Lanos 1.4 engine MeMZ 317, on which is an assembly of gas equipment of the 4th generation Stag 200 GoFast. All experiments were carried out on the equipment of the Training Center for Computer Diagnostics of Vehicles “Lviv Polytechnic – Bosch Academy”. A set of new Champion RN9YC spark plugs was used, the gap of which was changed from 0.6 to 1.4 mm with a pitch of 0.1 mm. According to the values of the gap between the electrodes of the spark plug, with the use of Bosch BEA 460 gas analyzer, the content of the following components of the exhaust gases CO, HC, O2 and CO2 is determined for two engine's crankshaft frequencies.
  • Thumbnail Image
    Item
    Optimal gear shift algorithm in the car transmission during its deceleration
    (Lviv Politechnic Publishing House, 2018-01-29) Hashchuk, Petro; Pelo, Roman; Lviv State University of Life Safety; Lviv Polytechnic National University
    On the way to improving the car one can not avoid the problem of optimal gear shift in stage transmissions. Typically, the gear (stage) shift laws are distinguished, which are optimal because of fuel efficiency, either in terms of dynamics (speed), or in terms of comfort / safety of the car, etc. And all these types of laws are considered to be special, irreducible to each other. Because of this, in the designs of real automotive transmissions, it is often foreseen for the driver to have several automatic control programs at the same time. But everything that is entrusted to the driver is to some extent the subjective negation of automaticity and optimality. The purpose of the work is to refute such very common system of views on the optimality of transmission control as: it turns out there is a single optimal gear shift law, within which there are no contradictions, at least between energy efficiency requirements and the requirements for the dynamics (or performance) of the vehicle. The basis of the research methodology is the fully motivated principle of non-interference of the automatic transmission control system in the choice of the car movement program - a choice that is largely due to the circumstances and road conditions of the vehicle movement. So, optimizing the gear shift laws, it is necessary to consider the movement program to be predetermined (subject only to the driver), and the consequences of forced deviation from it during the operation of the elements of transmission control should be minimized. Specifically, gear shifting is considered during the car deceleration. Direct involvement of the engine in the process of gear changes is envisaged, that is, the implementation of the principle of active synchronization of the rotation speed of separate parts of the transmission on adjacent gears during their shifting. In this case, the transmission of mechanical energy through the transmission is carried out by a continuous flow. The implementation of the dynamic principles of automation also leads to a decrease in the amount of mechanical energy that is transformed into heat during the skid of gear shift elements (frictions, for example). This makes it possible to increase the durability of the gear-shift elements or to impose lighter requirements in the process of designing the transmission. The described algorithm of the optimal transmission control of the car provides grounds for the formation of motivated guidelines for selecting the moments of gear shift also during purely manual control of the car. The obtained results are quite general, although significant simplifications were introduced into the car model. In particular, the scheme of the gearbox, considered to be very simple, actually fully reproduces the principles of work of the mechanical stage transmission of any structure. The process of gear shifting is so fast that the linearized reproduction of the operating modes of the “engine-transmission” system is quite natural and such that it can not distort the idea of the optimal functioning of the engine-transmission system.