Exhaust system
Contents
1. TECHNICIAN Exhaust system SAIL TRAINING ACADEMY Ss Way of Life SUZUKI Engine Auxiliary Systems Course code ENO5 Student training manual Suzuki Online Training Foreword This training manual contains basic information on the exhaust system We will study exhaust system components and their functions the catalytic convertor and exhaust gas analysis using the exhaust gas analyzer After your have completed this course also complete the relevant section in the Practical Activities Student Workbook and the online test Smart manuals Co Some sections of this training manual contain videos with detailed information on the topics you are studying If you are studying this training manual on a PC look out for the green play video symbol on any part of this training manual click on the green button to watch a video providing you with detailed information on that topic Note Internet connection required This document Is intended solely for training purposes only All vehicle repairs and adjustments must be carried out according to the procedures stipulated in current service manuals and technical bulletins ENO5 Engine Auxiliary System Starting system Suzuki Technician curriculum This training manual is part of the Non Suzuki Technician to Suzuki Technician curriculum The curriculum consists of the following modules GEO1 Suzuki Introduction GEO2 Electrical and Electronics2. catalytic converter ENO5 Engine Auxiliary System Starting system Function The main purpose of the exhaust system is to e Extract exhaust gases from the exhaust manifold and discharge them off at a suitable place in the vehicle e Reduce muffle exhaust gas noise produced during the combustion process of the internal combustion engine e Reduces environmental pollutants in the exhaust gases Figure 1 Exhaust system components Suzuki Kizashi ENO5 Engine Auxiliary System Starting system Exhaust system components The exhaust system is made up of the following components figure 1 1 Exhaust manifold 2 Warm up three way catalytic converter 3 Catalytic converter 4 Exhaust pipe No 1 5 Exhaust pipe No 2 6 Exhaust muffler 1 7 Exhaust muffler 2 8 Front muffler 9 A F sensor 10 HO2S gt Fresh air Exhaust gases Exhaust manifold Que The exhaust manifold is mounted directly onto the cylinder head exhaust side and it is made of pipes that cover the Openings of the exhaust ports on the cylinder head Its main function is to extract the exhaust gases and channel them into the exhaust pipes The exhaust system is usually made of cast iron stainless steel or light weight steel tubing A gasket is used between the cylinder head and the exhaust manifold to prevent leakage Catalytic Converter Figure 3 Catalytic converter Function The catalytic converter is an emission cont
3. of exhaust gas readings measured 14 Hydrocarbon HC levels gt Oxygen 02 Levels HC is un burnt fuel that remains as a result of misfire When Oxygen is measured by the exhaust gas analyzer in combustion doesn t take place or only part of the air fuel percentages The amount of oxygen produced by the charge burns hydrocarbon levels go up The hydrocarbons are engine is affected by how close the air fuel ratio is to measured by an exhaust analyzer in parts per million ppm stoichiometry As the mixture goes lean oxygen increases The following figures are offered as a guide Carburetor models The normal readings are below 1 5 Petrol injection and it decreases as the mixture goes rich At idle speed At 3000 rpm Poor Compressions Mixture too weak Valve timing incorrect ENO5 Engine Auxiliary System Starting system models Below 100 ppm Below 50 ppm Ignition misfire HC EMISSION TOO HIGH Engine designed with full vacuum advance at idle Below 300 ppm Leak in exhaust system Ignition misfire Below 100 ppm Incorrect ignition timing O2 readings above 1 5 Mixture too rich Ignition or valve timing Mixture excessively weak incorrect Dribbling injectors 15 Carbon Monoxide CO level Carburetor engines _ Carbon monoxide is measured by the exhaust analyzer in or parts per hundred CO is a byproduct of combustion the
4. will be able to e Name the gases that can be found in exhaust gases up Stream of the catalytic converter e Name the gases that can be found in the exhaust system down stream of the catalytic convertor e Describe the effect of the stoichiometric ratio in the composition of exhaust gases e Interpret exhaust gases ENO5 Engine Auxiliary System Starting system 10 The relevant gases and substances o Carbon Monoxide CO Hydrocarbons HC Nitrogen Oxides NOx Nitrogen dioxide NO2 Nitric oxide NO Hydrocarbons HC Oxygen 02 Carbon dioxide C02 Benzene A hydrocarbon Lead Pb ENO5 Engine Auxiliary System Starting system Effects of rich and lean mixtures on exhaust gases The concentrations of pollutants in the untreated exhaust gas upstream of the catalytic converter largely depend on the air fuel ratio A mixture composition in the stoichiometric ratio A 1 results in exhaust gases that have very low levels of pollutants The ideal theoretical stoichiometric ratio is 14 1 14 parts of air mixed with 1 part of fuel _ 0 975 1 0 1 025 1 05 rich Excess air factor A lean Figure 1 Effects of air fuel mixture on exhaust gases a Exhaust gases upstream of catalytic converter b Exhaust gases downstream of catalytic converter c Electrical voltage of two step A sensor 11 The perfect combustion HC from petrol O2 form the air 0
5. 12 4 14 1 16 4 18 4 _ Air Fuel Ratio W Perfect combus Figure 2 02 level against air fuel ratio A Stoichiometric band R Rich W Weak ENO5 Engine Auxiliary System Starting system The imperfect combustion Composition of exhaust gases HC from petrol O2 form the air E CO2 18 1 E H20 9 2 E N2 71 E O2 amp inert gases 0 7 Imperfect combustion E Pollutants 1 Figure 3 Composition of exhaust gases CO 0 85 HC 0 05 NOx 0 08 Solids 0 005 Figure 4 Composition of pollutants in exhaust gases ENO5 Engine Auxiliary System I Starting system 13 Exhaust gas analysis Use of the exhaust gas analyzer can be helpful in troubleshooting both emissions and drivability concerns engine malfunctions Figure 5 Exhaust gas analyzer ENO5 Engine Auxiliary System Starting system Diagnosis using exhaust gas analysis In troubleshooting always remember the combustion chemistry Fuel Hydrogen carbon sulfur air Nitrogen oxygen Carbon dioxide water vapor oxygen carbon monoxide hydrocarbon oxides of nitrogen sulfur oxides In any diagnosis of emission or drivability related concerns ask yourself the following questions What is the symptom What are the baseline exhaust readings At idle 2500 rpm acceleration deceleration light load cruise load Which sub systems or components could cause the combination
6. CT sensor or MAF sensor Faulty throttle body assembly Faulty APP sensor Faulty injector s Faulty ECM Engine not at normal operating temperature Clogged air cleaner Vacuum leak Camshaft position control system out of order Improper ignition timing Lead contamination of catalytic converter Fuel pressure out of specification Closed loop system A F feedback compensation fails faulty TP sensor poor performance of ECT sensor or MAF sensor Faulty throttle body assembly Faulty APP sensor Faulty injector s Faulty ECM Camshaft position control system out of order ENO5 Engine Auxiliary System Starting system Exhaust emissions analysis The following photo shows the analysis of exhaust gases in a Suzuki Swift AZH414 with no engine malfunctions HESHBON MEM HG 520 CO Ho HC Figure 6 Exhaust gas analysis Suzuki Swift CO 0 00 HC 0 ppm C02 12 8 02 0 07 1 003 Air Fuel Ratio 15 5 20 Summary A catalytic converter removes harmful pollutants from the exhaust gases though chemical reactions Excess oxygen in the exhaust gas results in increase NOx Oxygen reacts with the carbon monoxide and hydrocarbons to produce water and carbon dioxide The carbon monoxide reacts with NOx to produce nitrogen and carbon dioxide The exhaust mufflers are used to reduce exhaust noises generated during the combustion process The upstream oxygen sensor is used by the engine control
7. Diagnostics ENO2 Engine Mechanical part En03 Engine Mechanical part II ENO4 Engine Mechanical part III ENO5 Engine Auxiliary systems DS01 Driveshaft Axle DSO2 Driveshaft Axle transfer case 10 BRO2 Brake control systems 11 Manual transmission transaxle 12 CS02 Control system body electrical 13 CS03 Communication bus systems a at ee ee eS en iS You are currently studying ENO5 Engine Auxiliary Systems This module consists of the following courses e Charging systems e Starting systems e Exhaust system Click on the other training modules to view their training contents Table of contents Exhaust system 4 Exhaust components 5 Exhaust manifold 6 Catalytic converter 6 Muffler 9 Connecting pipes 9 Exhaust gas composition 10 The relevant gases and substances 11 Effects of stoichiometric ratio In catalytic converter efficiency 12 Composition of exhaust gases 13 Exhaust gas analysis 14 HC levels 15 O2 levels 15 Carbon Monoxide levels 16 Carbon dioxide levels 19 Suzuki exhaust symptom diagnosis 20 ENO5 Engine Auxiliary System Starting system Exhaust system In this lesson we will study the basic function of the exhaust system and its components Objectives At the end of this lesson you will be able to e Describe the function of the exhaust system e Name the basic components making up the exhaust system e Describe the functions of individual exhaust gas components e Describe the functions of the
8. ic converter and measure the amount of oxygen content in the exhaust gases The upstream oxygen sensor signal is used by the ECM to regulate very precisely the air fuel mixture for combustion to the value Lambda 1 The downstream oxygen sensor is used by the ECM to determine the efficiency of the catalytic converter Figure 6 Location of exhaust gas oxygen sensors 1 Catalytic Converter 4 Up stream oxygen sensor A F sensor 5 Down stream oxygen sensor H20S Muffler Exhaust mufflers smooth out exhaust gas pulsations and make them as inaudible as possible There are essentially two physical principles involved reflection and absorption E Figure 5 Exhaust muffler ENO5 Engine Auxiliary System Starting system Connecting pipes gt These are used to connect the exhaust components together e g connecting the catalytic converter tot the muffler At some instances flexible pipes are used to allow engine movement and reduce vibrations without passing it to the rest of the exhaust especially in front wheel drive vehicles It also helps with alignment of the pipes The complete exhaust system is secured to the vehicle using brackets and elastic mounting elements Figure 6 Dual exhaust mufflers Suzuki Kizashi 1 Connecting pipe Exnaust gas composition In this lesson we will study composition of the exhaust gases and the exhaust gas analyzer Objectives At the end of this lesson you
9. in the catalytic converter The harmful exhaust gasses react with the platinum to produce less harmful gases Platinum and palladium accelerate the oxidation of HC and CO while rhodium is responsible for reducing NOx ENO5 Engine Auxiliary System Starting system Two way catalytic convertors The two way catalytic convertor has two simultaneous tasks In this process Oxygen 02 reacts with Carbon monoxide CO to produce carbon dioxide C02 The Oxygen also reacts with hydrocarbons un burnt or partially burnt fuel to produce carbon dioxide CO2 and water H20 Two way catalytic convertors are unable to reduce Nitrogen Oxides Three Way Catalytic converter In addition to the two tasks performed by the Two way catalytic converter the Three Way Catalytic TWC convertor also uses carbon monoxide CO to convert Nitrogen Oxides NOx to Nitrogen N2 and Carbon dioxide C02 Reduction NOx CO gt N2 C02 Oxidation HC CO 02 gt H20 CO2 Figure 4 Function of the TWC Operating temperature of the catalytic converter Catalytic converters do not start significant conversion until they have reached a specific temperature On the TWC s this is approx 300 C Ideal conditions for high conversion rates are achieved at 400 C to 800 C figure 5 Exhaust gas oxygen sensor ENO5 Engine Auxiliary System Starting system Oxygen sensors WF Oxygen sensors are installed up stream and down steam of the catalyt
10. module correct the air fuel mixture The downstream oxygen sensor is used by the engine control module to monitor the efficiency of the catalyst Exhaust gas analysis can be used to diagnose engine malfunctions ENO5 Engine Auxiliary System Starting system Well done you have now completed the Exhaust system training course Please complete the online exam ENO5 Engine Auxiliary System Starting system ZZ
11. ncorrectly adjusted Control pressure too low K Jetronic Fuel pressure too high CO EMISSION TOO H IGH idle or cruise _ Air flow sensor incorrectly adjusted K Jetronic Injection duration too long electronic systems Worn injectors ENO5 Engine Auxiliary System Starting system Carbon Dioxide C02 level Carbon dioxide is a byproduct of efficient and complete combustion Near perfect combustion will result in carbon dioxide levels which approach the theoretical maximum of approximately 15 5 Carbon dioxide levels are affected by air fuel ratio spark timing and any other factors which affect combustion efficiency The minimum level should not be below 10 Poor Compressions Mixture too weak Valve timing incorrect Ignition misfire CO2 EMISSION TOO LOW Engine designed with full a a at i idle Incorrect ignition timing Mixture too rich Dribbling injectors 19 Suzuki exhaust emissions symptom diagnosis Excessive hydrocarbon HC or carbon monoxide CO emission Excessive nitrogen oxides NOx emission Faulty spark plug Faulty ignition coil with ignitor Low compression Lead contamination of three way catalytic converter Faulty evaporative emission control system Fuel pressure out of specification Closed loop system A F feedback compensation fails faulty TP sensor poor performance of E
12. ng Idle CO The CO is measured at the correct idle speed for the vehicle as specified by the service manual and compared with the manufacturers recommended figures Acceleration CO This can be measured by snapping open the throttle once and watching the CO level increase No Increase in CO after snap acceleration Cruising CO This can be measured by holding the engine at a steady 3000 Accelerator pump Induction system air i 4 linkage seized leak rom The readings should range between 0 and 1 on electronic systems and 0 and 2 5 on the K Jetronic Mechanical system ENO5 Engine Auxiliary System Starting system 17 Carbon Monoxide CO level Carbon Monoxide CO level Petrol injected engines continued Petrol injected engines continued Mixture incorrectly adjusted Throttle pot faulty Air flow sensor faulty Aur leak in induction trunking or manifold Fuel pressure too low No increase in CO after snap acceleration Control pressure too high K Jetronic Injection duration too short electronic systems CO EMISSION TOO LOW idle or cruise Air flow plate sticking Vacuum connection to pressure regulator faulty _ Air flow sensor incorrectly adjusted K Jetronic Blocked injector s Flow rate too low ENO5 Engine Auxiliary System Starting system 18 Carbon Monoxide CO level Petrol injected engines continued Mixture i
13. refore if combustion does not take place carbon monoxide will not be created Mixture incorrectly adjusted Float level too low Induction system air leaks Engine misfires Blocked jets CO EMISSION TOO LOW Check HC idle or cruise Anti run on valve Incorrect throttle plate position By pass idle carburettor In C Wrong jets fitted Sticking ENO5 Engine Auxiliary System Starting system Carbon Monoxide CO level Carburetor engines continued Mixture incorrectly adjusted om worn engine unburned fuel passing through breather A to richen mixture Worn needle worn loose jets or wrong jets fitted Float level too high carburettor flooding CO EMISSION TOO HIGH idle or cruise Carburettor diaphragms leaking Choked air filter Cold starting device stuck on Incorrect throttle plate position By pass idle carburettor 16 Carbon Monoxide CO level Carbon Monoxide CO level Carburetor engines continued Petrol injected engines The measure of CO percentage is used to assess the mixture Accelerator pump No oil in dashpot j diaphragm leaking Conan eA AeA strength of the vehicle The lower the CO level the weaker type carbuettors the mixture and conversely the higher the CO level the richer the mixture The CO level can be assessed under three different operating conditions Idle acceleration and cruisi
14. rol device added to the exhaust system to lower the levels of Hydrocarbon HC Carbon Monoxide CO and Oxides of Nitrogen NOx pollutants in exhaust gases A catalyst in the convertor chemically treats pollutants in the exhaust gases converting them to less harmful substances A Figure 2 Exhaust manifold 1 and catalytic catalyst causes a chemical reaction but after the reaction it converter 2 remains unchanged ENO5 Engine Auxiliary System Starting system Design The catalytic converter has a ceramic core housed in a Stainless steel shell The core contains many small passages through which the exhaust gas pass A thin coating of aluminum oxide covers these passages and has a rough Surface and is designed to provide a large surface area in the passages where the exhaust gasses pass Metal core This is made of finely corrugated 0 05mm thick metal foil wound around and brazed in a high temperature process It offers extremely low resistance to the flow of the gases Ceramic core The ceramic monolith is made of cordierite It has an extremely high stability to temperature and thermal shock but cannot be installed directly to the metal housing A special expanding mat is necessary to compensate for the difference between the thermal expansion coefficients of steel and ceramic and also protects the ceramic monolith against shocks Catalyst The catalyst is made of a precious metal Platinum is widely used as a Catalyst
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