Utjecaj povrata ispušnih plinova (EGR) na rad Ottovog motora

undergraduate thesis

• Title (english): The influence of exhaust gas recirculation (EGR) on SI engine operation
• Author: Martina Šimag
• Mentor: Darko Kozarac (mentor)
• Granter: University of Zagreb; Faculty of Mechanical Engineering and Naval Architecture; Zagreb
• Defense date and country: 2017-03-02, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Mechanical Engineering

Abstract

Emisije štetnih ispušnih plinova ograničene su strogim zakonskim propisima, zbog čega je zadatak inženjera pronaći načine na koji će smanjiti emisiju štetnih ispušnih plinova. Povrat ispušnih plinova razvio se prvenstveno kod Dieselovih motora kako bi smanjivao emisiju dušikovih oksida ograničavajući temperature u cilindru razrjeđivanjem svježeg zraka u usisu s određenim udjelom EGR-a .

Danas se povrat ispušnih plinova počeo primjenjivati i kod Ottovih motora zajedno s ostalim naprednim tehnologijama za smanjivanje emisija štetnih ispušnih plinova. Povrat ispušnih plinova kod Ottovih motora primarno se koristi kako bi smanjivao gubitke rada izmjene radne tvari pri djelomičnom opterećenju, tako poboljšavajući potrošnju goriva i sekundarno kako bi se smanjila emisija dušikovih oksida. Najveća prednost EGR-a je sposobnost smanjenja sklonosti detonantnom izgaranju.

Svrha ovog rada je istražiti utjecaj EGR-a na izgaranje i rad Ottovog motora. Istraživanje je provedeno na jednocilindarskom četverotaktnom Ottovom motoru pri različitim udjelima EGR-a. Mjerenja su se odvijala pri konstantnoj brzini vrtnje motora i stehiometrijskoj gorivoj smjesi.

Nakon provedene analize rezultata zaključuje se da se povratom ispušnih plinova smanjuje emisija dušikovih oksida s istovremenim povećanjem emisija neizgorjelih ugljikovodika i ugljikovog monoksida u ispušnim plinovima kao posljedica nepotpunosti procesa izgaranja. Također je prikazan utjecaj EGR-a na smanjenje potrošnje goriva i povećanje korisnosti motora te na ostale veličine kao što su tlak u cilindru, brzina oslobađanja topline te temperatura ispušnih plinova.

Abstract (english)

The exhaust emissions are limited by stringent regulations that are defined by the state government, which is why the task of engineers is to find ways to reduce exhaust emissions now days. Exhaust Gas Recirculation (EGR) was firstly adopted in diesel engine as one of the effective measures to reduce formation of nitrogen oxides by limiting the combustion chamber temperature thanks to the dilution of the fresh charge with a certain amount of exhaust gases at the engine intake.

Today, EGR is commonly used also in spark-ignited engine together with other advanced techniques. Exhaust Gas Recirculation on spark-ignited engine is employed primarily to reduce throttling loss at part load range, thus reducing the fuel consumption, and secondarily, to reduce the emission of nitrogen oxides. The crucial benefit of application of EGR is that it improves the detonation resistance at full load operation.

The aim of this work is to review the influence of EGR on engine combustion and running on spark-ignited engine. Investigation was carried out on a single-cylinder four-stroke spark-ignited engine at different EGR ratios. Measurements were carried out at constant load speed and with stoichiometric mixture.

From deep analysis, with the EGR the NOx emission is reduced with the increased rates of unburnt hydrocarbons and carbon monoxide as a result of incomplete combustion. The influence of EGR is also shown on reduced fuel consumption and increased engine efficiency as well as other values such as in-cylinder pressure, rate of heat release, exhaust temperature.

• Keywords: ispušni plinovi; ottov motor
• Keywords (english): EGR; ispitivanje motora; analiza rezultata
• Language: croatian
• URN:NBN: urn:nbn:hr:235:161031
• Study programme: Title: Mechanical Engineering; Study programme type: university; Study level: undergraduate; Academic / professional title: sveučilišni/a prvostupnik/ prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka strojarstva (sveučilišni/a prvostupnik/ prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka strojarstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2019-05-22 19:03:59