DESC:2
[001] The present subject matter relates to a protection system. More particularly to a protection system for NOx sensor.
[002] In the light duty vehicle, the NOx sensor gets failures, due to water traces or water splash inside the NOx sensor. Due to water condensation, NOx sensor starts cracking, because it is made-up of ceramic material (an insulated materials), which results into failures of sensor frequently.
[003] Therefore, there is an unmet need of protection system to enhance the shelf-life of the NOx sensor, thereby minimize the functional failure or efficiency of the NOx sensor and increase the shelf-life of the NOx sensor.
[004] The present subject matter solves the aforementioned and other problems by providing a protection system for NOx sensor to enhance the shelf-life of NOx sensor, thereby minimize the functional failure or efficiency of the NOx sensor.
[005] The present subject matter relates to a protection system for NOx sensor. The protection system for NOx sensor comprising (a) a cap configured to engage with NOx sensor and act as a mounting feature (b) an integrated tube configured to engage with the cap to ensure NOx sensor functionality (min flow criteria) (c) a NOx sensor protection cover to protect from water traces or water splash.
[006] As we are aware that NOx sensor is a very costly item and mostly get imported to India. Therefore, it is an important and crucial item in the light duty vehicles. Further post NOx sensor comes on tail pipe and the functionality of post NOx sensor is to measure tail pipe emissions and giving feedback to OBD architecture for statutory regulations. It is widely seen the positional failure reason of NOx sensor is water traces / splash going inside sensing filament of the NOx sensor, which is made-up of ceramic materials. The sensor gets cracked, due to condensation of water resultant sensor completely get failed.
[007] The protection system for NOx sensor protect the NOx sensor by NOx sensor heat up mode, wherein it is done by delaying the sensor activation till the temperature limits achieved. The temperature limit threshold is the only limited to dew point strategy and during start of vehicle warm up. Further this strategy does not work during vehicle running. The protection system takes care of NOx sensor functionality as well as protection from splash water. The NOx sensor cannot work 3
by Just shifting it to end CAP, in that case the flow velocity may largely drop < (lesser than) 10m/sec. This will happen because of same gases will distribute to much higher cross section hence velocity get reduce. To overcome this problem, an integrated tube concept with end cap has been evolved. Now since the gases are again pushed to flow within a small cross section of tube so the velocity increases and it meets the minimum criteria of 10 m/sec. Further the added protection system of protection covers in front of sensor (without disturbing the flow pattern) to protect it from outside water splash. The protection cover design is being optimized through various CFD iterations, so that NOx sensor sensitivity doesn’t gets disturbed.
[008] The post NOx sensor is mounts after all gas catalytic conversion, near tail pipe. The NOx sensor only operates when gases are moving across its probe, if the velocity of gases drops beyond 10 m/ sec; then its sensitivity drops sharply and chances of misdetection. If we put a NOx sensor in a chamber, which is filled of NOx gases but it’s stationary, it will not detect NOx values to ensure minimum velocity by 10 m/sec
[009] To illustrate the hybrid mixer in more details herein below:
BRIEF DESCRIPTION OF DRAWINGS
[0010] Aspects of the present disclosure are illustrated by way of example(s), and not by way of limitation, in the accompanying drawings, wherein:
[0011] FIG. 1 depicts tail portion of old design muffler 100
[0012] FIG. 2 is illustrating overall construction of post NOx sensor positioning on end CAP 200
[0013] FIG. 3 is illustrating cross sectional view of post NOx sensor positioning on end CAP 300.
[0014] FIG. 4 is illustrating complete sectional view of NOx sensor tube 400 of present invention.
DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS
[0015] FIG. 1 depicts tail portion of old design muffler 100, wherein post NOx sensor is at tail pipe. The limitation or disadvantages of this design is prone to water splashing and water can enter very easily inside.
4
[0016] FIG. 2 is illustrating overall construction of post NOx sensor positioning on end CAP 200 of the present invention. In this design, the NOx sensor 202 is position at the end CAP and a semi tubular section 204 is visible. The semi tubular section 204 is a complete tube, which ensuring mass flow for sensor sensitivity.
[0017] FIG. 3 is illustrating cross sectional view of post NOx sensor positioning on end CAP 300. The part 302 is the NOx sensor protection cover, which helps in preventing splashes coming from outside to inside muffler as described in figure 1.
[0018] FIG. 4 is illustrating complete sectional view of NOx sensor tube 400 of present invention. The part 402 is the NOx sensor protection cover, which helps in preventing splashes coming from outside to inside muffler as described in figure 1.
[0019] The NOx of present subject matter is implemented in light duty vehicle, where the wheelbase is of 2.5 to 6 m. In small vehicles longer tail pipe can’t be packaged. Also long tail pipe adds back pressure to overall system and engine. The technical advantage of this system is to protect the NOx sensor without affecting its functionality.
[0020] It is to be understood that other embodiments of the present disclosure will become readily apparent to those skilled in the art from the following detailed description, wherein it is shown and described only various embodiments of the disclosure by way of illustration. Accordingly, the drawings and description are to be regarded as illustrative in nature and not as restrictive.
[0021] It would become abundantly clear to a person in the art, after reading this specification that the present subject matter also provides a protection system for NOx Sensor to ensure its functionality, avoids misdetection. More specifically, the present subject matter relates to a protection system for NOx sensor to protect the NOx sensor by NOx sensor heat up mode, wherein it is done by delaying the sensor activation till temp limits achieved. The protection system takes care of NOx sensor functionality as well as protection from outside splash water, without the assistance or intervention of a tool or a technician and without departing from the spirit of the present subject matter. While the subject matter may be susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and have been described herein. Alternate embodiments or modifications may be practiced without departing from the spirit of the present subject matter. The drawings shown are schematic drawings and may not be to the scale. While the drawings show some features of the subject matter, some features may be omitted. Alternatively, in some other cases some features may be emphasized while others are not. Further, the methods disclosed herein may be performed in manner and/or order in which the methods are explained. Alternatively, the methods may be performed in manner or order different than what is explained without departing from the spirit of the present subject matter. It should be understood that the subject matter is not intended to be limited to the particular forms disclosed. Rather, the subject matter is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the subject matter. ,CLAIMS:We claim:
1) A protection system for NOx sensor comprising (a) a cap configured to engage with NOx sensor and act as a mounting feature (b) an integrated tube configured to engage with the cap to ensure NOx sensor functionality (min flow criteria) (c) a NOx sensor protection cover to protect from water traces or water splash.
2) The protection system for NOx sensor as claimed in claim 1, wherein the NOx sensor comes on tail pipe and the functionality of post NOx sensor is to measure tail pipe emissions and giving feedback to OBD architecture for statutory regulations.
3) The protection system for NOx sensor as claimed in claim 1, wherein said protection system for NOx sensor protect the NOx sensor by NOx sensor heat up mode and it is done by delaying the sensor activation till the temperature limits achieved.
4) The protection system for NOx sensor as claimed in claim 3, wherein the said temperature limit threshold is the dew point temperature limited to start of vehicle warm up
5) The protection system for NOx sensor as claimed in claim 1, wherein an integrated NOx with end CAP protection sensor protect the NOx effectively.