This present disclosure relates generally to a vehicle exhaust system, and more particularly to an exhaust system which is optimized to better monitor and adjust the air fuel ratios in a vehicle engine.
Internal combustion engines utilize feedback from Exhaust Gas Oxygen (EGO) sensors to maintain desired air-fuel ratio mixtures during combustion, at least under some conditions. The EGO sensors are part of the emissions control system and feeds data to the engine control module (ECM) to adjust the fuel to air ratio for the vehicle engine. Various types of EGO sensors may be used, such as linear type sensors, sometimes referred to as Universal Exhaust Gas Oxygen (UEGO) sensors, and switching type sensors such as Heated Exhaust Gas Oxygen (HEGO) and Exhaust Gas Oxygen (EGO) sensors, depending on whether a heater is included.
As is known, a vehicle engine burns gasoline in the presence of oxygen. It turns out that there is a particular ratio of air and gasoline that is “perfect,” and that ratio is 14.7:1. It is understood that different fuels may have different “perfect ratios”—the ratio depends on the amount of hydrogen and carbon found in a given amount of fuel. If there is less air than this perfect ratio, then there will be fuel left over after combustion. This is called a rich mixture. Rich mixtures are bad because the unburned fuel creates pollution. If there is more air than this perfect ratio, then there is excess oxygen. This is called a lean mixture. A lean mixture tends to produce more nitrogen-oxide pollutants, and, in some cases, it can cause poor performance and even engine damage.
Oxygen sensors are positioned in the exhaust pipe and can detect rich and lean mixtures in each of the engine cylinders. The mechanism in most sensors involves a chemical reaction that generates a voltage. The engine's computer looks at the voltage to determine if the mixture is rich or lean, and adjusts the amount of fuel entering the engine accordingly in order to make sure that all engine cylinders are operating correctly and under uniform conditions.
The reason why the engine needs the oxygen sensor is because the amount of oxygen that the engine can pull in depends on various things, such as the altitude, the temperature of the air, the temperature of the engine, the barometric pressure, the load on the engine, etc. In internal combustion engines equipped with an exhaust catalyst to reduce undesirable emissions, it has been found that modulation of the air-fuel ratio to rich and lean of stoichiometric conditions may also improve the efficiency of the catalyst under some conditions. One application of EGO sensors is to provide feedback upon which air-fuel ratios may be modulated. One prior approach involved modulating the air-fuel ratio using feedback from a Catalyst Monitor Sensor (CMS) such as a HEGO sensor to identify the stoichiometric conditions around which modulation was to take place.
Accordingly, it would be desirable in the industry to produce a vehicle exhaust system which is designed to provide accurate post O2 sensor data feedback to the engine control module in order to correctly modulate the air-fuel ratio.
Accordingly, the present disclosure provides an exhaust system for a vehicle having a catalytic converter, an exhaust manifold, an inlet sensor, an outlet sensor in addition to inlet and outlet pipes. The catalytic converter includes an integrated oxygen sensor mount, an entry, and an outlet. The integrated oxygen sensor mount may be operatively configured to mix the exhaust gas and may be configured to receive any one of a variety of oxygen sensors. The exhaust manifold is configured to couple a vehicle combustion chamber to the entry of the catalytic converter via a front pipe. The inlet oxygen sensor may be affixed to the front pipe upstream of the catalytic converter wherein the inlet oxygen sensor and the outlet oxygen sensor are in communication with an engine control module. The outlet pipe may be affixed to the outlet of the catalytic converter.
The present disclosure also contemplates the non-limiting example of an exhaust system having an exhaust manifold, a catalytic converter, a first catalytic converter pipe, a second catalytic converter pipe, an integrated oxygen sensor mount, and an engine control module wherein the integrated oxygen sensor mount is formed in at least one of the first catalytic converter pipe and the second catalytic converter pipe. The catalytic converter includes an inlet and an outlet. The first catalytic converter pipe may be affixed to the entry of the catalytic converter and the second catalytic converter pipe may be affixed to the outlet of the catalytic converter. The integrated sensor mount may be operatively configured to receive an oxygen sensor. The exhaust manifold may be operatively configured to couple a vehicle combustion chamber to the entry of the catalytic converter via the first catalytic converter pipe. The engine control module may be in communication with the oxygen sensor and a secondary oxygen sensor.
The present disclosure and its particular features and advantages will become more apparent from the following detailed description considered with reference to the accompanying drawings.
These and other features and advantages of the present disclosure will be apparent from the following detailed description of preferred embodiments, and best mode, appended claims, and accompanying drawings in which:
FIG, 4 is an enlarged perspective view of the integrated oxygen sensor mount on a catalytic converter of the present disclosure.
Like reference numerals refer to like parts throughout the description of several views of the drawings.
Reference will now be made in detail to presently preferred compositions, embodiments and methods of the present disclosure, which constitute the best modes of practicing the present disclosure presently known to the inventors. The figures are not necessarily to scale. However, it is to be understood that the disclosed embodiments are merely exemplary of the present disclosure that may be embodied in various and alternative forms. Therefore, specific details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for any aspect of the present disclosure and/or as a representative basis for teaching one skilled in the art to variously employ the present disclosure.
Except in the examples, or where otherwise expressly indicated, all numerical quantities in this description indicating amounts of material or conditions of reaction and/or use are to be understood as modified by the word “about” in describing the broadest scope of the present disclosure. Practice within the numerical limits stated is generally preferred. Also, unless expressly stated to the contrary: percent, “parts of,” and ratio values are by weight; the description of a group or class of materials as suitable or preferred for a given purpose in connection with the present disclosure implies that mixtures of any two or more of the members of the group or class are equally suitable or preferred; the first definition of an acronym or other abbreviation applies to all subsequent uses herein of the same abbreviation and applies mutatis mutandis to normal grammatical variations of the initially defined abbreviation; and, unless expressly stated to the contrary, measurement of a property is determined by the same technique as previously or later referenced for the same property.
It is also to be understood that this present disclosure is not limited to the specific embodiments and methods described below, as specific components and/or conditions may, of course, vary. Furthermore, the terminology used herein is used only for the purpose of describing particular embodiments of the present disclosure and is not intended to be limiting in any way.
it must also be noted that, as used in the specification and the appended claims, the singular form “a,” “an,” and “the” comprise plural referents unless the context clearly indicates otherwise. For example, reference to a component in the singular is intended to comprise a plurality of components.
The term “comprising” is synonymous with “including,” “having,” “containing,” or “characterized by.” These terms are inclusive and open-ended and do not exclude additional, unrecited elements or method steps.
The phrase “consisting of” excludes any element, step, or ingredient not specified in the claim. When this phrase appears in a clause of the body of a claim, rather than immediately following the preamble, it limits only the element set forth in that clause; other elements are not excluded from the claim as a whole.
The phrase “consisting essentially of” limits the scope of a claim to the specified materials or steps, plus those that do not materially affect the basic and novel characteristic(s) of the claimed subject matter.
The terms “comprising”, “consisting of”, and “consisting essentially of” can be alternatively used. Where one of these three terms is used, the presently disclosed and claimed subject matter can include the use of either of the other two terms.
Throughout this application, where publications are referenced, the disclosures of these publications in their entireties are hereby incorporated by reference into this application to more fully describe the state of the art to which this present disclosure pertains.
The following detailed description is merely exemplary in nature and is not intended to limit the present disclosure or the application and uses of the present disclosure. Furthermore, there is no intention to be bound by any theory presented in the preceding background or the following detailed description.
Referring now to
Each combustion chamber 20 in the engine 18 is connected to an exhaust manifold 14, 16, through which exhaust gases 42 from the combustion reaction in the combustion chambers 20 are transferred to a catalytic converter 30, 32. As previously noted, the exhaust manifold 14, 16 may be coupled to the engine 18 at the combustion chambers 20. The exhaust system 10 according to the present disclosure however is not restricted to combustion engines having a specific number of cylinders/chambers and can be used with various types of combustion engines.
Each of the exhaust manifolds 14, 16 is connected to corresponding front pipes, 34, 36 in which catalytic converters 30, 32 are provided for purifying the exhaust gas. A muffler 40 is provided downstream of the front pipe such that the respective portions of the front pipe 34, 36 may extend to the inside of the muffler 40. The muffler 40 is affixed to outlet pipe 44 where exhaust gases 42 are transmitted to the atmosphere.
In order to make sure that the vehicle engine 18 is provided the right mixture of air and fuel, an exhaust monitoring system 56 is implemented which includes an inlet oxygen sensor 48 (mounted at inlet/front pipe 34) as well as an outlet oxygen sensor 50 (mounted on a catalytic converter 30, 32) via integrated oxygen sensor mount 38. The inlet oxygen sensor 48 and/or outlet oxygen sensor 50 are responsible for keeping the air/fuel ratio of the mixture entering the engine 18 at the optimal level, which is approximately 14.7:1 or 14.7 parts of air to 1 part of fuel. When the inlet oxygen sensor 48 and/or outlet oxygen sensor 50 senses high level of oxygen content 60 (shown in
The exhaust monitoring process is continuous. The ECM 46 and the engine 18 constantly cycles between slightly lean and slightly rich conditions to keep the air/fuel ratio at the optimum level. This process is called closed loop operation. With reference to
As shown ire schematic
Outlet oxygen sensor 50 may be one of a variety of standard oxygen sensors which are commercially available in the automotive industry. The outlet oxygen sensor 50 may he received in the integrated oxygen sensor mount 38 and may measure the amount of oxygen 60 in the exhaust gases 42 via shroud 72 of the integrated oxygen mount 38. With reference to
Referring again to
With reference to
With reference to
As shown in
Noting that the apertures 70 in the shroud 72 may but not necessarily be spaced apart from the openings 82 in the sensor's steel shell 78 by a distance 150 (shown in
Therefore, as a result of the swirling or turbulence in the exhaust gas flow 42 proximate to the outlet oxygen sensor 50 (which is mounted to the catalytic converter 30, 32) the exhaust system 10 of the present disclosure may obtain a more accurate reading of the oxygen 62 levels in the exhaust gas flow 42. Again, this vehicle exhaust system 10 arrangement may accommodate a variety of types of oxygen sensors from various oxygen sensor manufacturers thereby providing a cost-efficient system vehicle system for vehicle manufacturers. Accordingly, regardless of which type of oxygen sensor implemented, the vehicle exhaust system 10 of the present disclosure provides an improved detection rate for the outlet oxygen sensor 50.
With reference to
Similar to the first embodiment having an integrated sensor mount 38 in the catalytic converter 30, 32 shown in
While one row 68 of apertures 70 are shown in
Noting that the apertures 70 in the shroud 72 for the catalytic converter pipe 37 are spaced apart from the apertures 70 in the steel shell which surrounds the sensing element, it is understood that exhaust gases 42 proximate to the oxygen sensor may flow through both sets of apertures 70—shroud apertures 70 and steel shell openings 82. As a result of having the exhaust gases 42 flow through both sets of apertures 70 and openings 82, the exhaust gases 42 may be mixed before they reach the sensing element 76 (
As noted, as a result of the swirling or turbulence in the exhaust as flow 42 proximate to the oxygen sensor 51, the exhaust system 10 of the present disclosure may obtain a more accurate reading of the oxygen content levels in the exhaust gas flow 42. Similar to the first embodiment describing a catalytic converter having an integrated oxygen sensor mount 38, this vehicle exhaust system arrangement with a catalytic converter pipe 37 with an integrated oxygen sensor mount 38 may accommodate a variety of types of oxygen sensors from various oxygen sensor manufacturers thereby providing a cost-efficient system vehicle system for vehicle manufacturers. Accordingly, regardless of which type of oxygen sensor implemented, the vehicle exhaust system of the present disclosure provides an improved detection rate for any oxygen sensor 50, 50′ which may be implemented.
While at least one exemplary embodiment has been presented in the foregoing detailed description, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration of the disclosure in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing the exemplary embodiment or exemplary embodiments. It should he understood that various changes can be made in the function and arrangement of elements without departing from the scope of the disclosure as set forth in the appended claims and the legal equivalents thereof.