Internal combustion engine

Abstract

An internal combustion engine. An internal combustion engine (100) is provided comprising a sensor (110) for sensing the concentration of unburned oxygen in the exhaust gas of the engine (100), and an intersection path (140) for passing gas in the exhaust gas of the engine (100). The sensor (110) is positioned directly within the flow path (140f) of the exhaust gas from the combustion chamber (150). The crossing path (140) has a thicker path (140D) and a thinner path (140d) connected to each other to form a closed path for recirculating exhaust gas for the warm-up sensor (110). A sensor (110) is positioned within and at the distal end of the crossing path (140), and proximate the spark plug (124) and on the right side of the engine. The present invention reduces the response time for maintaining an optimal air-fuel mixing ratio in an engine (100), thereby improving efficiency and reducing emissions.

Description

Technical Field

[0001] The present invention relates to internal combustion engines, and more particularly, to lambda sensors in internal combustion engines. Background Art

[0002] Technology has enabled continuous improvements in the performance of modern vehicles using various digital control systems. These control systems rely on inputs provided by different types of sensors in the vehicle to control the engine, monitor emissions, etc. It is desirable that the sensors provide accurate and real-time data so that the response time for the control unit is reduced. Types of sensors include mass air flow sensors, engine speed sensors, spark knock sensors, pressure sensors, oxygen sensors, etc. Oxygen sensors are also called lambda sensors. This sensor is present in the exhaust system of the vehicle.

[0003] In an internal combustion engine, a lambda sensor (oxygen sensor) is a small probe near the vehicle's exhaust. It is usually located between the engine's exhaust manifold and the catalytic converter. The lambda sensor senses the concentration of gases (such as oxygen) in the engine's exhaust and sends a signal to the electronic control unit (ECU) based on the oxygen concentration to adjust the amount of fuel sent to the engine cylinders by optimizing the composition of the air and fuel mixture. This helps to improve the efficiency of the engine. In addition, this also reduces the amount of harmful gas emissions by ensuring that the catalytic converter is working properly. Therefore, the lambda sensor helps to ensure that the vehicle meets the standard regulations for pollution and CO2 emissions. Since the lambda sensor is placed before the catalytic converter, it can measure the amount of air and fuel in the unburned hydrocarbons after combustion. The electronic control unit (ECU) that controls certain functions of the engine will receive the correct data about the emissions and then release the exact amount of gas required. This is crucial in reducing polluting emissions. The arrangement of sensors before and after the catalytic converter allows the hygiene of the exhaust to be maintained and the efficiency of the converter to be checked.

[0004] It is also known in the art to place two such lambda sensors in a vehicle: one positioned in the exhaust pipe just after the catalytic converter, and one positioned in the cylinder head in the exhaust port.

[0005] In existing internal combustion engines, the lambda sensor is immersed in the inside of the exhaust port from the top of the exhaust port. In order to operate normally, the lambda sensor needs to be heated to a certain temperature. Thus, in order to realize the preheating of the lambda sensor, preferably, if the sensor is located near the exhaust port, they will heat up quickly and provide data good enough to be used for closed-loop operation in a few seconds of engine start-up. Further, the distance between the exhaust valve and the position where the sensor is installed and the significant time of the response of its sensitive element are important for the effective operation of the sensor.

[0006] This existing arrangement places the oxygen sensor away from the exhaust valve and at a significant distance from the exhaust valve. This distance is significant enough to cause a delay in the response time of the engine's control system. The exhaust valve is placed down to the exhaust port. Therefore, when the valve is open, there is a significant delay in the time for the gas to reach the oxygen sensor, which is undesirable.

[0007] In a known prior art, a multi-cylinder internal combustion engine includes a cylinder head that defines exhaust passages internally, the exhaust passages extending from a plurality of combustion chambers that are partially defined by the cylinder head. The exhaust passages converge into a convergence region that is also defined internally in the cylinder head. An oxygen sensor for detecting the oxygen concentration in the exhaust gas enters the convergence region substantially parallel to the cylinder axis. As a result, the oxygen sensor can be mounted relatively close to the combustion chamber while allowing the sensor to be uniformly exposed to the exhaust gas from the combustion chamber of the entire cylinder group. Despite being close to the combustion chamber, its sensitive element has a significant response time, which can cause a delay in the continued maintenance of the fuel mixture, thereby affecting the performance of the oxygen sensor. Further, because the oxygen sensor requires a suitable higher temperature to operate, it is also necessary to place a preheated oxygen sensor here.

[0008] In another known prior art, an internal combustion engine management system uses an exhaust system sensor that senses exhaust gases by extracting exhaust gases from the exhaust device of the engine. In some instances, this is done directly from the cylinder, while in other instances, this is done in the exhaust system. However, in each case, the sensor is arranged in an accumulator chamber to provide an accurate signal of the instantaneous engine operating conditions. The use of the accumulator chamber ensures that the combustible gas is not diluted by the fresh air intake, but can be purified from one cycle to another, thereby providing cycle-by-cycle information. Various arrangements for protecting sensor elements are provided, including serpentine flow paths, shielding, the direction of exhaust gas delivery, lubricant catalysts, conduit shapes, sensor cooling, and combinations of these features. In addition, various structural elements help to protect the exterior of the oxygen sensor (such as a housing) from damage, place the sensor in an engine recess, and form the sensor in one piece in the cylinder block. Therefore, there is a delay in the continuous maintenance of the air-fuel mixture.

[0009] In another prior art, a cylinder head of an internal combustion engine has an intake valve and an exhaust valve arranged in a V-shape, wherein an exhaust port is bent from an axis of the exhaust valve in a direction opposite to the intake valve, and a mounting surface for an exhaust member is formed at a downstream end of the exhaust port. A mounting structure for an exhaust gas sensor, wherein the exhaust gas sensor is positioned at a periphery of the mounting surface so as to protrude from an outer side surface of the exhaust port in a condition where the exhaust gas sensor is inclined relative to the axis of the cylinder.

[0010] In the prior art arrangement, the distance between the exhaust valve and the location where the sensor is mounted (the top of the exhaust port) is significant. This distance is significant enough to affect the response time of its sensitive element. This can cause undesirable system delays without preventing the continued maintenance of a stoichiometric fuel mixture, thereby affecting the effective performance of the oxygen sensor and the engine. Further, it is desired that the sensor reaches an optimal performance temperature and also remains at the desired optimal temperature while the engine is running. Further, since a separate opening must be present in the exhaust port, the compactness of the engine is affected. In addition, if any cracks occur in the exhaust port due to such an opening of the oxygen sensor, incorrect data measurements from the oxygen sensor will result.

[0011] Therefore, there is a need in the art for an internal combustion engine with an oxygen sensor that at least solves the above problems. Summary of the invention

[0012] In one aspect, the invention relates to an internal combustion engine, comprising a sensor for sensing the concentration of a gas in the exhaust of the engine, and a cross-path for passing the gas in the exhaust of the engine. The sensor is mounted on a cylinder head of the engine. The sensor is positioned directly within the flow path in the direction of the flow path of the exhaust gas out of the combustion chamber through the exhaust valve of the engine. The cross-path has a thicker path and a thinner path. The diameter of the thicker path is greater than the diameter of the thinner path. The sensor is positioned within the cross-path.

[0013] In one embodiment, the coarser path is substantially consistent with the flow path. The coarser path implements and directs the exhaust gas toward the sensor. The sensor is positioned within the distal end of the coarser path.

[0014] In one embodiment, the sensor is an oxygen sensor. The oxygen sensor is configured to measure the concentration of oxygen in the gas in the exhaust gas. The oxygen sensor has a longitudinal arm for retaining the sensor in the cylinder head.

[0015] In one embodiment, the sensor is positioned adjacent to a spark plug of the engine and substantially closer to the spark plug than to an exhaust port of the engine. The sensor is positioned adjacent to a valve stem of an exhaust valve and directly aligned with a valve opening of an exhaust valve of the engine. The sensor is positioned adjacent to the spark plug and on the right side of the vehicle relative to a vehicle rider.

[0016] In one embodiment, the crossover path enables recirculation of gases in the exhaust of the engine. The recirculation occurs in the cylinder head of the engine and enables preheating of the sensor.

[0017] In one embodiment, the cylinder head has a sensor opening positioned adjacent to the spark plug. The sensor is mounted on the cylinder head through the sensor opening. The internal combustion engine includes a plug top. The plug top is configured to close at least a portion of the crossover path. The plug top enables access to the crossover path. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Reference will be made to embodiments of the present invention, examples of which are illustrated in the accompanying drawings. These drawings are intended to be illustrative, not restrictive. Although the present invention is generally described in the context of these embodiments, it should be understood that it is not intended to limit the scope of the present invention to these specific embodiments.

[0019] Figure 1 A cross-sectional front view of a portion of an internal combustion engine according to an embodiment of the present invention is illustrated.

[0020] Figure 2 A cylinder head of an internal combustion engine according to an embodiment of the present invention is illustrated in a perspective view.

[0021] Figure 3 A cylinder head of an internal combustion engine according to an embodiment of the present invention is illustrated in another perspective view.

[0022] Figure 4 A cylinder head of an internal combustion engine according to an embodiment of the present invention is illustrated in yet another perspective view. DETAILED DESCRIPTION

[0023] The present invention relates to internal combustion engines. More particularly, the present invention relates to sensors for sensing the concentration of exhaust gases in internal combustion engines.

[0024] Figure 1 A cross-sectional front view of a portion of an internal combustion engine 100 according to an embodiment of the present invention is illustrated. As an example, the engine 100 is a single-cylinder, two-valve engine, typically used in two-wheeled vehicles such as scooters, motorcycles, etc. In other embodiments, the engine 100 is a multi-valve, multi-cylinder engine, in which the cylinders are arranged in a V-shaped arrangement, etc.

[0025] The engine 100 includes a sensor 110 for sensing the concentration of a gas in the exhaust gas of the engine 100 and a cross path 140 for passing the gas in the exhaust gas of the engine 100. The sensor 110 is mounted on the cylinder head 120 of the engine 100. The sensor 110 is directly positioned in a flow path 140f of the exhaust gas from the combustion chamber 150 through the exhaust valve 130 of the engine 100. The sensor 110 is directly positioned in line with and in the direction of the flow path 140f of the exhaust gas. The cross path 140 has a coarse path 140D and a fine path 140d (also in FIG. 140f). Figure 3 ).

[0026] The crossover path 140 provides a passage for the exhaust gas in the cylinder head 120 and is directly connected to the exhaust valve opening in the cylinder head 120. The diameter of the thicker path 140D is greater than the diameter of the thinner path 140d. The sensor 110 is positioned in the crossover path 140. The thicker path 140D starts from the exhaust valve opening and extends to the distal end, at least to the sensor location. The thinner path 140d starts from the location where the thicker path 140D ends at the distal end and connects to the thicker path 140D. The thinner path 140d ends at the distal end of the thicker path 140D to the exhaust port of the engine 100 and connects thereto.

[0027] In one embodiment, the coarser path 140D is substantially aligned with the direction of the flow path 140f. The coarser path 140D directs and guides the exhaust gas toward the sensor 110. The sensor is positioned within the distal end of the coarser path 140D.

[0028] After the combustion cycle is completed in the engine 100, when the exhaust valve 130 opens, the exhaust gas travels in the direction of the flow path 140f, through the coarser path 140D. The gases in the exhaust gas contact the sensor 110 located within and at the distal end of the coarser path 140D. The sensor measures the concentration of the gas within the exhaust.

[0029] Figure 2 A cylinder head 120 according to an embodiment of the present invention is illustrated in a perspective view. In one embodiment, the sensor 110 is an oxygen sensor. The oxygen sensor is configured to measure the concentration of oxygen in the exhaust gas. The oxygen sensor has a longitudinal arm 110a for holding the sensor in the cylinder head 120.

[0030] In one embodiment, sensor 110 is a lambda sensor. Lambda sensors, also known as oxygen sensors, measure the amount of unburned oxygen present in the exhaust gas. The output of sensor 110 is used to regulate the air / fuel mixture in engine 100. Sensor 110 helps determine whether the air-fuel ratio is low or high.

[0031] Reference again Figure 1In one embodiment, the cross path 140 enables recirculation of the exhaust gas of the engine 100. The recirculation occurs in the cylinder head 120 of the engine 100 and enables preheating of the sensor 110. Once the exhaust gas contacts the sensor 110, the exhaust gas is then directed and enters the finer path 140d to recirculate inside the exhaust valve 130 and the cylinder head 120. After recirculation, the exhaust gas is led out of the cylinder head 120 toward the muffler assembly connected to the engine 100. The sensor 110 has a heating sensor (not shown). The sensor 110 needs to be heated to reach the optimal performance temperature. The heating sensor helps to determine whether the sensor 110 has reached the optimal operating temperature. For example, the optimal temperature of the lambda sensor is 300°C to 600°C. The recirculation achieved by the cross path 140 enables the sensor 110 to reach the optimal temperature and maintain the temperature.

[0032] When the engine 100 reaches the correct temperature, the sensor 110 begins to measure the unburned oxygen present in the exhaust gas. This output is sent to the control unit, which calculates the air-fuel ratio and checks a lookup table to optimize it. Based on this information, the calculated amount of fuel required for the engine 100 to burn at a stoichiometric ratio is released, ensuring complete combustion.

[0033] Reference again Figure 2 In a preferred embodiment, the sensor 110 is positioned adjacent to the spark plug 124 of the engine 100 and substantially closer to the spark plug 124 than the exhaust port 126 of the engine 100. The sensor 110 is positioned near the valve stem of the exhaust valve 130 and is directly aligned with the valve opening of the exhaust valve 130 of the engine 100. In a preferred embodiment, the sensor 110 is positioned adjacent to the spark plug 124 and on the right side of the vehicle relative to the vehicle rider / driver. While the vehicle rider / driver is riding / driving the vehicle in a normal / conventional position, the sensor 110 is positioned on the engine 100 on the right side of the vehicle rider / driver. The sensor is placed so that it coincides with the opening angle of the exhaust valve 130. This substantially eliminates or at least reduces the delay of the exhaust gas contacting the sensor 110.

[0034] Figure 4 Another perspective view illustrates a cylinder head 120 of an engine 100 according to an embodiment of the present invention. The cylinder head 120 has a sensor opening 110o positioned adjacent to a spark plug 124. The sensor 110 is mounted on the cylinder head 120 through the sensor opening 110o. The engine 100 includes a plug top 110p. The plug top 110p is configured to close at least a portion of the crossover path 140. The plug top 110p enables access to the crossover path 140. In one embodiment, the plug top 110p is made of aluminum.

[0035] Advantageously, the present invention provides a sensor arrangement in an internal combustion engine that eliminates the problem of distance between the exhaust valve and the sensor, thereby reducing response time. This allows for continued and better maintenance of a stoichiometric air-fuel mixture, thereby eliminating delays in the effective performance of the oxygen sensor. Furthermore, the crossover path created inside the engine allows for recirculation of hot exhaust gases inside the engine, thereby eliminating the need to preheat the oxygen sensor, since the sensor will remain continuously heated by the hot exhaust gases when close to the exhaust valve opening.

[0036] Further, the lambda sensor or oxygen sensor is placed on the side of the spark plug instead of on the exhaust port. Since the location of the sensor is near the spark plug side of the engine, the engine compactness is also maintained.

[0037] While the present invention has been described with respect to certain embodiments, it will be apparent to those skilled in the art that various changes and modifications may be made without departing from the scope of the invention as defined in the following claims.

[0038] List of reference numerals:

[0039] Internal combustion engine: 100

[0040] Sensors: 110

[0041] Longitudinal arm: 110a

[0042] Cylinder head: 120

[0043] Spark plug: 124

[0044] Exhaust ports: 126

[0045] Flow path: 140f

[0046] Sensor opening: 110o

[0047] Plug top: 110p

[0048] Crossing paths: 140

[0049] Thicker path: 140D

[0050] Thinner path: 140d

[0051] Exhaust valve: 130

[0052] Combustion chamber:150.

Claims

1. An internal combustion engine (100), comprising: a sensor (110) for sensing the concentration of a gas in the exhaust gas of the engine (100), the sensor (110) being mounted on a cylinder head (120) of the engine (100), wherein the sensor (110) is positioned directly within a flow path (140f) of the exhaust gas from a combustion chamber (150) through an exhaust valve (130) of the engine (100); and A cross path (140) is used for allowing the gas in the exhaust gas of the engine (100) to pass through, the cross path (140) having a thicker path (140D) and a thinner path (140d), the diameter of the thicker path (140D) being larger than the diameter of the thinner path (140d), and the sensor (110) is positioned in the cross path (140).

2. The internal combustion engine (100) according to claim 1, wherein: The coarser path (140D) is substantially consistent with the flow path, the coarser path (140D) enables and directs the exhaust gas toward the sensor (110), which is positioned within a distal end of the coarser path (140D).

3. The internal combustion engine (100) according to claim 1, wherein: The sensor (110) is an oxygen sensor configured to measure the concentration of oxygen in the gas in the exhaust gas, and has a longitudinal arm (110a) for retaining the sensor (110) within the cylinder head (120).

4. The internal combustion engine (100) according to claim 1, wherein: The sensor (110) is positioned adjacent to a spark plug (124) of the engine (100) and is substantially closer to the spark plug (124) than to an exhaust port (126) of the engine (100).

5. The internal combustion engine (100) according to claim 1, wherein: The sensor (110) is positioned near a valve stem of the exhaust valve (130) and is directly aligned with a valve opening of the exhaust valve (130) of the engine (100).

6. The internal combustion engine (100) according to claim 1, wherein: The crossover path (140) enables recirculation of gas in the exhaust gas of the engine (100), the recirculation being carried out in the cylinder head (120) of the engine (100) and enabling preheating of the sensor (110).

7. The internal combustion engine (100) according to claim 1, wherein: The cylinder head (120) has a sensor opening (110o), the sensor (110) is mounted on the cylinder head (120) through the sensor opening (110o), and the sensor opening (110o) is positioned adjacent to the spark plug (124).

8. The internal combustion engine (100) according to claim 7, wherein: The internal combustion engine (100) includes a plug top (110p) configured to close at least a portion of the crossover path (140), the plug top (110p) enabling access to the crossover path (140).

9. The internal combustion engine (100) of claim 1, wherein: The sensor (110) is positioned adjacent to the spark plug (124) and on the right side of the vehicle relative to a vehicle rider.

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