Diagnostics and adaptation of the gas fuel supply control system in a spark ignition engine.
Students Name: Sahaiko Serhii Serhiiovych
Qualification Level: magister
Speciality: Motor Vehicle Transport
Institute: Institute of Mechanical Engineering and Transport
Mode of Study: full
Academic Year: 2020-2021 н.р.
Language of Defence: ukrainian
Abstract: Sagaiko S, Britkovsky V. (head). Diagnostics and adaptation of the gas fuel supply control system in a spark ignition engine. Master’s qualification work. - National University "Lviv Polytechnic", Department of "Operation and repair of automotive equipment". - Lviv, 2020. The technical development of society leads to an increase in the number of vehicles for the movement of population and goods. With the growth of the world fleet of vehicles, the amount of emissions of harmful substances into the atmosphere is increasing. To curb this increase, many countries are introducing exhaust gas toxicity standards for vehicle engines. The limits in the toxicity standards adopted by a country depend on the technical and economic levels of development. The most developed countries have stricter requirements for exhaust gas toxicity. Currently, there are several common types of alternative fuels for cars: liquefied petroleum gas, natural gas, bio-diesel, hydrogen. The object of research - the processes of adaptation and diagnosis of gas fuel control systems. The subject of research - the impact of methods of adaptation and diagnosis of control systems for gas supply on the performance of cars. The purpose of the work is to increase the performance of cars running on gas. The substantiation of the use of natural gas for internal combustion engines in the period of transition to higher requirements for exhaust gas toxicity is performed. The analysis of gas fuel supply generations is carried out. To meet modern and promising requirements for the toxicity of exhaust gases of the internal combustion engine requires the use of gas cylinder equipment, at least the 4th generation with an electronic engine management system. The analysis showed that the use of gaseous fuels imposes its features on: filling the cylinders with a gas-air mixture; choice of consumption characteristics of the electromagnetic nozzle; change of power and engine torque during the transition from liquid to gaseous fuel; design of the engine fuel system taking into account safety requirements. The requirements to the elements of gas cylinder equipment are considered. The effect of the pressure drop on the injector valve and the influence of the supply voltage on the injector valve on its flow characteristic are shown theoretically. The characteristics and design differences of gas injectors are considered, the main ones are the linearity of the reaction time of its injector. The exact volume of the gas mixture is affected by the following factors: the installation angle of the fitting; the size of the length of the hoses going from the fittings to the nozzles; the installation point of the fitting based on the design of the block head. The parameters of gas nozzles popular in Ukraine are compared. The comparison of gas nozzle parameters was carried out according to the main indicators, it gave the following results: Barracuda and Hana nozzles are the best in terms of linearity; Keihin and Barracuda are the best in terms of reaction time, followed by Valtek by a wide margin; on the performance of the nozzle set, the best performance for Keihin and Barracuda; for stability of parameters from temperature and for stability of parameters taking into account wear, the best Baraccuda. Methods of adaptation and diagnostics of gas-balloon equipment of the car are presented. The variance in the performance of the set of injectors that stand on the engine negatively affects the performance of the internal combustion engine, in the first place it is poor car dynamics, fuel consumption and unstable operation of the internal combustion engine in various modes, including idling. To compensate for the scatter of productivity, a method of correction of gas injectors on the signal of the oxygen sensor is proposed. With its help it is possible to estimate and correct rather cylindrical balance of gas nozzles in the idling mode quickly enough, without application of any additional tools. The only condition for the implementation of this technique is a connected oxygen sensor to the appropriate input of the gas controller. Key words - gas equipment, injector, diagnostics, oxygen sensor, adaptation.