WO2016063194A2

WO2016063194A2 - Self-cleaning poppet egr valve

Info

Publication number: WO2016063194A2
Application number: PCT/IB2015/058026
Authority: WO
Inventors: Kabir BHANDARI; Sandeep Kumar ANTIL; Amit Kumar LAL
Original assignee: Padmini Vna Mechatronics Pvt. Ltd.
Priority date: 2014-10-19
Filing date: 2015-10-19
Publication date: 2016-04-28
Also published as: WO2016063194A3

Abstract

This invention relates to an improved design of Poppet EGR Valve for self-cleaning feature wherein the EGR valve piston is enabled to execute dual direction movement in forward as well as reverse direction thereby automatically cleaning the soot deposited during the valve operation that leads to sticky piston after prolonged persistent use. The present invention adds a unique feature in the conventional poppet type EGR enabling it to clean the soot deposited on the valve seat, thereby obviating the blocking of valve which is one of the predominant reasons of valve failure.

Description

"SELF-CLEANING POPPET EGR VALVE"

FIELD OF THE INVENTION The invention relates to a Self-cleaning Poppet EGR Valve in a motor vehicle. More particularly, this invention relates to an improved design of Poppet EGR Valve for programmed self-cleaning wherein the EGR valve piston is enabled to have bidirectional movement in forward as well as reverse direction, thereby cleaning the soot deposited during continual and persistent valve operation.

BACKGROUND OF THE INVENTION

During operation period of engine when combustion temperature is very high, the nitrogen oxides emission is found as a major part of engine exhaust, which is one of the major components which cause air pollution. To prevent the formation of NOx the engine peak in-cylinder temperature has be to lowered which is done by adulating the fresh air with a part of engine exhaust which lead to improper combustion and hence reduction in peak cylinder temperature. Exhaust gas recirculation (EGR) system is designed to achieve this reduction in temperature which reduces the amount of oxides of nitrogen produced. This is done by re-circulating a controlled/regulated small amount of exhaust gas through EGR valve.

The re-circulated engine exhaust gas, laden with contaminants, comes in contact with many moving parts within the EGR valve including the valve orifice, piston and shaft. Contaminants get deposited on such moving parts, and may accumulate over time. The contaminants may accumulate to a level affecting EGR valve performance. For example, buildup of contaminants on the shaft can reduce clearance between the shaft and the bushing (or bearing) through which the shaft travels and results in increasing the frictional load on the shaft which reduces dynamic performance and can result in restriction in valve motion. Additionally, build-up on the piston or about the orifice can prevent a sealed engagement between the piston and the orifice. The contamination can increase a difference between actual and desired dilution of the engine fresh air charge, potentially increasing engine emissions and decreasing engine performance.

In conventional Poppet type EGR valves, the piston moves only in one direction to regulate exhaust gas flow and rest against a valve seat which restricts the valve movement in opposite direction. Exhaust soot keep on accumulating on valve seat area with the usage. Since conventional poppet type EGR valve doesn't have any positive self-cleaning feature thereby necessitating replacement of this integral pollution system component i.e. EGR valve. Therefore it is desirable to develop an EGR valve, wherein the EGR valve poppet has means of self-cleaning feature while operation. The EGR valve design allows the EGR valve piston to move forward and reverse direction; thereby self cleaning is done automatically by the movement of piston itself.

OBJECT OF THE INVENTION

The main object of the invention is to provide a unique Poppet EGR valve having self cleaning feature.

Yet another object of the invention is to provide a means that enables EGR valve piston to move in forward as well as reverse direction.

Yet another object of the invention is to provide a retractable piston ring, installed on the piston rod for restricting the axial movement allowing the exhaust gases to enter into the engine during normal operation and executing backward movement on programmed application.

Yet another object of the invention is to enable self-cleaning of the soot deposited in a Poppet EGR valve by forward and reverse motion of valve piston/poppet in valve seat area. Yet another object of the present invention is to provide an EGR valve which is capable of having its valve seat and closure element/piston ring cleaned.

Yet another object of the invention is to prevent the blocking of Poppet EGR valve.

Yet another object of the invention is to improve the performance and reliability of Poppet EGR valve.

Still another object of the invention is to increase the shelf-life of Poppet EGR valve.

SUMMARY OF THE INVENTION

The invention relates to a self-cleaning Poppet EGR Valve utilized in a motor vehicle. More particularly, this invention relates to an improved design of Poppet EGR Valve for self-cleaning feature wherein the EGR valve piston is enabled to execute dual direction movement in forward as well as reverse direction thereby automatically cleaning the soot deposited during the valve operation, that leads to sticky piston after prolonged persistent use. The present invention adds a unique feature in the conventional poppet type EGR enabling it to clean the soot deposited on the valve seat, thereby obviating the blocking of valve which is one of the predominant reasons of valve failure.

In one aspect, the present invention is directed to a mechanism for allowing valve piston in an exhaust gas recirculation (EGR) valve assembly in a motor vehicle to move forward as well reverse direction resulting in self cleaning of the soot deposited in the valve seat of the EGR valve during operation. The EGR valve for an engine comprising a means for mounting the valve to an engine, including an inlet adapted to receive exhaust gas, and an outlet adapted to communicate the received exhaust gas to the intake of the engine and a valve seat positioned about the inlet and a piston connected to valve shaft, a piston ring fixed on the periphery of the piston is adapted to move forward as well as reverse direction. While moving in forward direction the piston would regulate the EGR flow and while moving reverse direction the piston would clean the soot deposited on valve seat.

In one aspect, the present invention provides a retractable piston ring, installed on the piston rod for restricting the axial movement allowing the exhaust gases to enter into the engine during normal operation and executing backward movement on progra mmed application wherein the retractable piston ring, is pulled backwards under programmed application which retracts the edges thereby allowing the backward movement of the piston and clearing up any particulate matter that may have accumulated due to facilitated intake of the exhaust gases due to axial piston movement.

In yet a nother aspect of the invention, the present invention provides a secondary va lve seat that restricts the backward movement of the piston a nd rests on the housing.

Thereby, the present invention is directed to a valve maintenance method providing for periodic valve self cleaning operations having no associated emissions or performance penalty.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from the detailed

description and the accompanying drawings, wherein: FIG. 1 is a sectional view showing a conventional Poppet EGR valve;

FIG. 2 is a view showing Piston movement in both directions i.e. Reverse direction for soot cleaning and Forward direction to regulate EGR flow according to the invention;

FIG. 3 is a view showing exhaust gas flow direction; and FIG. 4 is a view showing exploded view of Poppet EGR valve according to the invention. DESCRIPTION OF THE PREFERRED EMBODIMENT

Hereinafter, embodiments of the invention will be described in detail with reference to the accompanying drawings.

However, the invention is not limited to the following embodiments, but can be modified in va rious forms.

As shown in Fig. 1, a sectional view showing a conventiona l Poppet EGR valve is illustrated. The conventional Poppet EGR valve comprising of Actuator assembly 1, U- arm 2, CAM shaft 3, CAM 4, Seal Gas 5, Guide Bush 7, Scrapper 8, Piston rod 9, Valve seat 10, Piston ring 11, and Piston 12. The Poppet EGR valve includes housing means supported by the mounting means including an atmospheric chamber a nd a vacuum chamber. The housing means including mea ns for communicating vacuum to the vacuum chamber and a valve seat 10 & piston ring assembly supported by the housing means for dividing the housing means into the atmospheric and vacuum chambers. The assembly further includes piston 12 means comprising an upper element adapted to receive the inner portion of the piston ring 11, a rod extending from the upper element through the inlet and an outward opening valve closure element for seating upon the valve seat 10. A default position arrangement is operationally configured in such manner that the EGR valves piston 12 moves only in one direction to regulate exhaust gas flow and rest against a valve seat 10 which restricts the valve movement in opposite direction.

As shown in FIG. 2, a view showing exploded view of conventional Poppet EGR valve according to the invention is illustrated. The conventional Poppet EGR valve comprising of Actuator assembly 1, U-arm 2, CAM shaft 3, CAM 4, Seal Gas 5, Guide Bush 7, Scrapper 8, Piston rod 9, Valve seat 10, Piston ring 11, and Piston 12.

As shown in FIG. 3, Piston 12 movements in both directions is elucidated i.e. reverse direction for soot cleaning and forward direction to regulate EGR flow according to the invention is illustrated. While moving in forward direction the piston 12 would regulate the EGR flow and while moving in reverse direction the piston 12 would clean the soot deposited on valve seat 10. At Position 1, the Piston 12 movement is in reverse direction or backward movement for soot cleaning; at Position 2, the Piston 12 is in neutral position; and at Position 3, the Piston movement in forward direction to regulate EGR flow. Thereby, the EGR valve is directed to a maintenance method providing for periodic valve self cleaning operations.

In the most preferred mode of operation the piston assembly 400 comprising of a piston ring 11, a piston rod 9 and a primary valve seat 10. The piston ring 11 is attached radially to the piston rod 9 for restricting the axial movement of the piston rod 9 by engaging into the valve seat 10 which is supported on the housing assembly 500; the housing assembly 500 provides passage for exhaust gases located in the lower side of the piston assembly, from which the piston rod 9 allows restrictive flow of the exhaust into the engine; the actuator assembly 100 seated co-axially on the piston assembly and attached to a piston assembly, controlling the piston and therefore the gas flow; and the CAM assembly 200 which translates the gear box rotary output to a valve shaft linear motion, employed between actuator output drive shaft and valve shaft wherein the piston assembly 400 is modified comprising of a modified piston ring 13, a piston rod, a primary valve seat 14 and a secondary valve seat ring 16 attached radially to piston rod ;the modified piston ring 13 providing retractable edges allowing backward movement of the piston rod 9, when modified piston ring 13 is stopped by the primary valve seat 14, on programmed application the piston rod 9 is pulled back and the retractable edges allows backward movement clearing off the particulate settlement; and a secondary valve seat 16 positioned anterior to the primary valve seat 14, restricting the axial movement of the piston rod after the piston rod 9 is pulled back and the retractable edges allows backward movement clearing off the particulate settlement by engaging into the secondary valve seat 16 that is supported on the housing assembly 500.

As shown in FIG. 4, a view showing exhaust gas flow direction is illustrated. Accordingly, the invention comprises an EGR valve for self-cleaning feature wherein the EGR valve piston is enabled to have automatic movement in forward as well as reverse direction thereby cleaning the soot deposited during the valve operation.

In the embodiment described above, the system according to the present invention was described as applied to the engine for an automotive vehicle. The system according to the present invention is not limited to such an application. It can be applied similarly to various engines useful as power sources, and can bring about similar advantages.

The invention is not restricted to the embodiments described above. The embodiments are not intended as limitations on the scope of the invention. Processes, methods, apparatus, compositions, and the like described herein are exemplary and not intended as limitations on the scope of the invention. Changes therein and other uses will occur to those skilled in the art. The scope of the invention is defined by the scope of the claims.

Claims

CLAIMS We Claim:

1. A modified EGR valve comprising:

a housing assembly having slots for fitting various assemblies and further providing atmospheric and vacuum chambers;

an actuator assembly fitted into said housing;

a piston assembly seated co-axially on said actuator assembly comprising a piston, a piston ring, a piston rod and a primary valve seat;

a CAM assembly which translates a gear box rotary output to a valve shaft linear motion, employed between an actuator output drive shaft and a valve shaft; and a valve body assembly fitted co-axially on said actuator assembly and said piston assembly;

Wherein: said piston assembly having a modified piston ring providing retractable edges allowing backward movement of the piston rod, when the modified piston ring is stopped by the primary valve seat, on programmed application the piston rod is pulled back and the retractable edges allows backward movement clearing off the particulate settlement; and a secondary valve seat positioned on top of the primary valve seat, restricting the axial movement of the piston rod after the piston rod is pulled back by engaging into the secondary valve seat that is supported on the housing assembly.

2. The modified EGR valve as claimed in claim 1, wherein said modified piston ring installed on the piston rod.

3. The modified EGR valve as claimed in claim 1, wherein said modified piston ring retracts the edges under programmed application.

4. The modified EGR valve as claimed in claim 1, wherein the said programmed application provides a periodic valve self cleaning operations having no associated emissions or performance penalty.

5. The modified EGR valve as claimed in claim 1, wherein said piston is enabled to execute bi-directional movement in forward as well as reverse direction thereby automatically cleaning the soot deposited during the valve operation.

6. The modified EGR valve as claimed in claim 1, utilizes an electrical actuator based on DC Motor or Torque motor or Solenoid.

7. The modified EGR valve as claimed in claim 1, wherein said secondary valve seat piston is made up of stainless steel or materials alike.

8. The modified EGR valve as claimed in claim 1, wherein said modified piston ring is made up of stainless steel or materials alike.