An exhaust system for processing exhaust gases

Abstract

The claimed matter discloses an exhaust system 102 for processing exhaust gases of an internal combustion engine 104. The exhaust system 102 comprises an exhaust pipe for channeling exhaust gases, at least one first catalytic converter 302, 402 and at least one second catalytic converter 304, 404. The at least one first catalytic converter 302, 402 and the at least one second catalytic converter 304, 404 are disposed in series in the exhaust pipe. The volume of the at least one noble metal used in the at least one first catalytic converter 302, 402 is lesser than the volume of the at least one noble metal used in the at least one second catalytic converter 304, 404.

Description

TITLE OF THE INVENTIONAN EXHAUST SYSTEM FOR PROCESSING EXHAUST GASESTechnical field

[0001] The claimed subject matter in general relates to exhaust systems for internal combustion engines. The claimed subject matter, in particular relates to optimization of catalytic converters used in the exhaust systems.Background

[0002] The motor vehicles which use internal combustion engine for power generation, need to process the exhaust gases before releasing them into the atmosphere. Some of the harmful gases coming out of the exhaust port of the combustion engine are unbumt hydrocarbons (HC), carbon monoxide (CO), nitrogen oxide (NO2) and Nitric oxide. These harmful gases need to be processed to convert them into less harmful gases. One of the major components used in the exhaust gas treatment is a catalytic converter (CATCON).

[0003] The catalytic converter typically consists of a ceramic structure coated with a metal catalyst, usually platinum, rhodium and / or palladium. These are referred as noble metals. The structure exposes the maximum surface area of the catalyst to the exhaust gases.

[0004] When the exhaust gases come in contact with the surface of the catalytic converter, a chemical reaction takes place. In the catalytic converter, oxygen is used in oxidation and reduction reactions to convert harmful gases into less harmful substances.

[0005] The catalytic converter requires a certain operating temperature, typically around 250 degrees Celsius, to efficiently convert emissions. However, a common challenge faced by traditional catalytic converters is the delay in reaching this optimal temperature, particularly during the initial start-up of the vehicle. This delay, known as the "light-off time," results in higher emissions during the initial phase of engine operation when the catalytic converter is not yet fully effective. This extended light-off time leads to increased emissions during theinitial minutes of engine operation, contributing significantly to the overall emission output of the vehicle.

[0006] Further, catalytic converters rely on noble metals (such as platinum, palladium, and rhodium) to facilitate the chemical reactions that convert exhaust gases. However, a higher noble metal content can lead to the catalytic converter operating at temperatures beyond the safe operating zone, potentially causing damage to the catalytic converter and reducing its efficiency and lifespan.

[0007] The claimed subject matter addresses these issues.Summary

[0008] The claimed subject matter is defined in the independent claims. Further details are defined in the dependent claims.

[0009] The claimed subject matter relates to exhaust systems for processing the exhaust gases in internal combustion engines. The claimed subject matter proposes a system for processing of exhaust gases and a method of manufacturing the system.

[0010] The solution in the claimed subject matter proposes at least two catalytic converters disposed in series in an exhaust path / exhaust pipe. At least one catalytic converter, referred as a first catalytic converter, is smaller in volume compared to the other catalytic converter, referred as second catalytic converter. The first catalytic converter is disposed upstream of the second catalytic converter in the exhaust path in the direction of flow of the exhaust gases. The volume of the first catalytic converter may be between 80% and 99% of the volume of the second catalytic converter. Further, the volume of the at least one noble metal used in the first catalytic converter is 25% to 75% lower than the volume of the second catalytic converter.

[0011] The features discussed herein and advantages of the claimed subject matter will be better understood with reference to the detailed description, drawings and claims. This summary is provided to introduce the claimed subject matter in a simplified form. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.Brief description of the drawings

[0012] The detailed description is described with reference to the accompanying figures. In the figures, similar reference numerals are used throughout the drawings to reference like features and components.Figure 1 illustrates a two wheeled motor vehicle.Figure 2 illustrates a system for processing exhaust gases in prior arts.Figure 3 illustrates a system for processing exhaust gases in one embodiment according to the claimed subject matter.Figure 4 illustrates a system for processing exhaust gases in another embodiment according to the claimed subject matter.Figure 5 illustrate a method of manufacturing an exhaust system.Detailed description

[0013] The claimed subject matter now will be described with exemplary embodiments. However, the claimed subject matter may be embodied in many different forms and should not be construed as limited to the embodiments described herein. These embodiments are provided only as examples so that this disclosure is clear and concise.

[0014] Some of the terms used in this document may be used with different expressions and also interchangeably. Some examples are given below.

[0015] The expression ‘exhaust gases’ or ‘gases’ may be used to indicate processed exhaust gases or unprocessed exhaust gases or both. The expression ‘exhaust path’ may be used to indicate an exhaust pipe connected to the IC engine. The expressions ‘Internal combustion engine’, ‘IC engine’ and ‘engine’ may be used interchangeably. The expression vehicle may be used to mean a two wheeled motor vehicle, a three wheeled motor vehicle or a four wheeled motor vehicle or all of them. The claimed subject matter is applicable to all types of vehicles. The expressions ‘two wheeled motor vehicle’, ‘motor vehicle’ and ‘vehicle’ may be used interchangeably. The expressions ‘first’ and ‘second’, while referring to ‘first CATCON or ‘second CATCON’ are used only symbolically and have no other attribute. These expressionsmay also be used interchangeably. The expressions ‘exhaust system’ and ‘system’ may be used interchangeably.

[0016] Only the details / components required to describe the claimed subject matter in specific, are disclosed in this document. The details / components which are commonly known or understood by people skilled in the art may not be covered in this document.

[0017] Figure 1 illustrates a typical two wheeled motor vehicle 100 according to one embodiment.

[0018] The two wheeled motor vehicle 100 is supported by a frame assembly, not shown. The two wheeled motor vehicle 100 includes a front wheel steered by a handlebar and a rear wheel. A rider seat for a rider and a seat for a pillion rider are placed rearward to a fuel tank. The Internal Combustion, IC, engine 104 is typically disposed below the fuel tank on the front portion of the two wheeled vehicle 100.

[0019] The IC engine 104 typically comprises an inlet port, an exhaust port or exhaust pipe / path, a combustion chamber, a crank shaft, a cam shaft, various valves, sensors etc. These are not shown in figures. Combustion chamber is where the fuel and air mixture is ignited. During the combustion process fuel ignites, creating high pressure gases that drive the engine’s 104 piston. The exhaust gases from the engine 104 pass through the exhaust system 102.

[0020] Figure 2 illustrates an exhaust system 102 for processing exhaust gases in prior arts. The system 102 comprises an exhaust pipe whose one end is connected to the exhaust port of the engine 104 and the other end is open to the atmosphere. A catalytic converter CATCON, not shown, is disposed in the exhaust pipe. Typically an oxygen sensor 204 is disposed in the exhaust pipe downstream of the CATCON. The exhaust gases entering the CATCON are normally referred as unprocessed exhaust gases and the exhaust gases coming out of the CATCON are referred as processed exhaust gases. The oxygen sensor 204 provides the information regarding the level of oxygen present in the processed exhaust gases. The level of oxygen is an indication of how efficiently the CATCON is functioning. As the chemical reaction in the CATCON uses part of the oxygen from the unprocessed exhaust gases, the level of oxygen in the processed exhaust gases indicates how efficiently the chemical reaction is happening, thereby indicating how efficiently the harmful exhaust gases are converted to lessharmful substances. Typically a controller (not shown) reads the data from the oxygen sensor 204 and may use the data to control some of the parameters of the engine 104.

[0021] There may be other components present in the exhaust system 102, for example, components for reducing noise in the exhaust pipes. However these are not described in this document.

[0022] Traditional catalytic converters, which are designed with a single, large-volume, experience a prolonged light-off time. This is the period during which the catalytic converter is not yet effective because it has not reached the optimal temperature (approximately 250 degrees Celsius) required to convert harmful emissions into less harmful substances. During this time, the vehicle emits higher levels of pollutants, contributing to overall air pollution.

[0023] CATCONs rely on noble metals (such as platinum, palladium, and rhodium) to facilitate the chemical reactions that convert exhaust gases. However, a higher noble metal content can lead to the CATCON operating at temperatures beyond the safe operating zone, potentially causing damage to the CATCON and reducing its efficiency and lifespan.

[0024] The proposed solution in the claimed subject matter addresses these issues.

[0025] Figure 3 illustrates a system 102 for processing exhaust gases in one embodiment according to the claimed subject matter.

[0026] The system 102 comprises the exhaust pipe as explained in previous paragraphs. At least one first CATCON 302 and at least one second CATCON 304 are disposed in series in the exhaust pipe. The at least one first CATCON 302 is disposed upstream of the at least one second CATCON 304 in the direction of the flow of the exhaust gases.

[0027] In one embodiment, the at least one first CATCON 302 is smaller in volume compared to the volume of the at least one second CATCON 304. In one embodiment the volume of the at least one CATCON 302 is about 80% to 99% of the at least one second CATCON 304.

[0028] By incorporating at least one first CATCON 302 which is smaller in volume compared to the at least one second CATCON 304, the proposed system 102 enables the at least one first CATCON 302 to heat up more quickly. This reduced volume ensures a faster attainment of theoptimal temperature, thereby decreasing the light-off time and reducing emissions during the engine start-up.

[0029] Figure 4 illustrates a system 102 for processing exhaust gases in another embodiment according to the claimed subject matter.

[0030] The system comprises the exhaust pipe as explained in previous paragraphs. At least one first CATCON 402 and at least one second CATCON 404 are disposed in series in the exhaust pipe. In one embodiment the volumes of the two CATCONs 402, 404 may be same. In one embodiment the at least one first CATCON 402 is smaller in volume compared to the volume of the at least one second CATCON 404. The at least one first CATCON 402 is disposed upstream of the at least one second CATCON 404 in the direction of the flow of the exhaust gases.

[0031] The CATCONs 402, 404 use noble metals like Ruthenium, Rhodium, Palladium and Platinum. In one embodiment, the volume of the at least one noble metal used in the at least one first catalytic converter 402 is lower than the volume of the at least one noble metal used in the at least one second catalytic converter 404. In one embodiment the volume of the noble metals used in the at least one first CATCON 402 is 25% to 75% lesser than the volume of the noble metals used in the at least one second CATCON 404.

[0032] The lower volume of the noble metals in the at least one first CATCON 402, provides controlled chemical process of reaction and reduction, thereby preventing the at least one first CATCON 402 from operating beyond safe temperature limits while still maintaining effective reduction of harmful emissions, thereby enhancing durability and cost-efficiency.

[0033] In one embodiment, the at least one first CATCON 302, 402 has lesser volume compared to the at least one second CATCON 304, 404, as well as the at least one first CATCON 302, 402 has lesser volume of the at least one noble metal compared to the volume of the at least one noble metal used in the at least one second CATCON 304, 404.

[0034] Figure 5 illustrates a method 500 of manufacturing the system 102 for processing exhaust gases. Only the specific steps required for the claimed subject matter are described. The steps which are commonly known are omitted. The method step 502 discloses manufacturing an exhaust pipe. The exhaust pipe may be for any kind of motor vehicle. Themethod step 504 discloses manufacturing at least one first CATCON 302, 402 and disposing it in the exhaust pipe. The method step 506 discloses manufacturing at least one second CATCON 304, 404 and disposing it in the exhaust pipe downstream of the at least one first catalytic converter 302, 402 in the direction of the flow of the exhaust gases, wherein the volume of the at least one noble metal used in the at least one first CATCON (302, 402) is lesser than the volume of the at least one noble metal used in the at least one second CATCON (304, 404).

[0035] The further method steps are disclosed in dependent claims. The method of manufacturing comprises manufacturing the at least one first catalytic converter 302, 402 with a volume which is between 80% and 99% of the volume of the at least one second catalytic converter 304, 404.

[0001] The proposed solution has multiple technical advantages, for example, some are described below:

[0036] Reduced Light-off Time: The at least one first CATCON 302, 402 which is smaller in volume, heats up more quickly due to its smaller volume. This allows the CATCON 302, 402 to reach its optimal operating temperature faster, significantly reducing the light-off time. Rapid attainment of the optimal temperature leads to lower emissions during the initial startup phase of the engine 104, thus improving the vehicle’s overall emissions performance and environmental compliance.

[0037] Efficient reduction of harmful emissions: The at least one first CATCON 302, 402, with its optimized noble metal content, ensures effective reduction of harmful emissions without the risk of overheating. Maintaining the at least one first CATCON 302, 402 within a safe operating temperature range prevents damage and degradation of the converter, ensuring sustained high performance in reduction of harmful emissions.

[0038] Enhanced Durability and Longevity: By preventing the at least one first CATCON 302, 402 from exceeding safe temperature limits, the risk of thermal degradation and premature wear is minimized. This enhances the durability and longevity of the at least one first CATCON 302, 402, reducing the need for frequent replacements and maintenance, thereby lowering the overall cost of maintenance of the vehicle.

[0039] Improved overall System Efficiency: The dual-catalytic converter configuration, with a smaller, quicker-to-heat first CATCON 302, 402 and a larger, more robust second CATCON 304, 404 ensures that the exhaust system 102 operates efficiently under various driving conditions. This results in an overall improvement in the vehicle’s emissions control system, providing consistent performance, meeting regulatory standards, and contributing to better fuel efficiency.

[0040] The oxygen sensors 204 are positioned in such a way that they provide accurate status of the processing of the exhaust gases. One oxygen sensor 204 is positioned upstream of the CATCONs 302, 402 and the other oxygen sensor is positioned downstream of the CATCONs 304, 404. This arrangement provides the oxygen contents in the unprocessed exhaust gases and also in the processed exhaust gases so that the controller can accurately compute engine parameters leading to efficient reduction of harmful gases and also longer durability of the exhaust system.Reference numerals and their description:100 Vehicle102 Exhaust system104 Engine 204 Oxygen sensor302, 402 First catalytic converter304, 404 Second catalytic converter

Claims

We claim:

1. An exhaust system (102) for processing exhaust gases of an internal combustion engine (104), the exhaust system (102) comprising:- an exhaust pipe for channeling exhaust gases;- at least one first catalytic converter (302, 402); and- at least one second catalytic converter (304, 404), wherein the at least one first catalytic converter (302, 402) and the at least one second catalytic converter (304, 404) being disposed in series in the exhaust pipe, and wherein the volume of the at least one noble metal used in the at least one first catalytic converter (302, 402) being lesser than the volume of the at least one noble metal used in the at least one second catalytic converter (304, 404).

2. The exhaust system (102) for processing exhaust gases of an internal combustion engine (104) as claimed in claim 1, wherein the at least one first catalytic converter (302, 402) being placed upstream of the at least one second catalytic converter (304, 404) in the direction of the flow of the exhaust gases.

3. The exhaust system (102) for processing exhaust gases of an internal combustion engine (104) as claimed in claim 1, wherein the at least one first catalytic converter (302, 402) being smaller in volume compared to the volume of the at least one second catalytic converter (304, 404).

4. The exhaust system (102) for processing exhaust gases of an internal combustion engine (104) as claimed in claim 3, wherein the volume of the at least one first catalytic converter (302, 402) being between 80% and 99% of the volume of the at least one second catalytic converter (304, 404).

5. The exhaust system (102) for processing exhaust gases of an internal combustion engine (104) as claimed in claim 1, wherein the volume of the at least one noble metal used in the at least one first catalytic converter (302, 402) being 25% to 75% lower than the volume of the at least one noble metal used in the at least one second catalytic converter (304, 404).

6. The exhaust system (102) for processing exhaust gases of an internal combustion engine (104) as claimed in claim 1, wherein the at least one noble metal is selected from Ruthenium, Rhodium, Palladium and Platinum.

7. A method (500) of manufacturing an exhaust system (102) for processing exhaust gases of an internal combustion engine (104), the method comprising:- manufacturing (502) an exhaust pipe;- manufacturing (504) at least one first catalytic converter (302, 402) and disposing it in the exhaust pipe; and- manufacturing (506) at least one second catalytic converter (304, 404) and disposing it in the exhaust pipe downstream of the at least one first catalytic converter (302, 402) in the direction of the flow of the exhaust gases, wherein the volume of the at least one noble metal used in the at least one first catalytic converter (302, 402) being lesser than the volume of the at least one noble metal used in the at least one second catalytic converter (304, 404).

8. The method (500) of manufacturing the exhaust system (102) for processing exhaust gases of an internal combustion engine (104) as claimed in claim 7, comprising manufacturing the at least one first catalytic converter (302, 402) which has smaller volume compared to the at least one second catalytic converter (304, 404).

9. The method (500) of manufacturing the exhaust system (102) for processing exhaust gases of an internal combustion engine (104) as claimed in claim 8, comprising manufacturing the at least one first catalytic converter (302, 402) having a volume which is between 80% and 99% of the volume of the at least one second catalytic converter (304, 404).

10. The method (500) of manufacturing an exhaust system (102) for processing exhaust gases of an internal combustion engine (104) as claimed in claim 7, comprising manufacturing the at least one first catalytic converter (302, 402) having a volume of the at least one noble metal used in the at least one first catalytic converter (304, 404) which is being 25% to 75% lower than the volume of the at least one noble metal used in the at least one second catalytic converter (304, 404).

11. The method (500) of manufacturing an exhaust system (102) for processing exhaust gases of an internal combustion engine (104) as claimed in claim 1, comprising selecting the at least one noble metal from Ruthenium, Rhodium, Palladium and Platinum.

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