DESC:FIELD OF INVENTION
[0001] The present invention relates to a NOx reduction mechanism for an internal combustion engine and more particularly to NOx reduction by using a throttle controlled continuously regulated EGR (exhaust gas recirculation) mechanism.
BACKGROUND OF INVENTION
[0002] In general, an exhaust gas is emitted through a combustion process. The exhaust gas is actually a combination of many different gases like N2, CO2, CO, H2O, NO, and NO2etc. Though some are harmless, there are few that are harmful and are considered major pollutants. NO, and NO2 (combined called as NOx) are produced due to high temperature inside the combustion chamber. Devices for treating some components of exhaust gases (like HC, CO) uses the oxidation catalytic converters thereby these components are reduced from the exhaust gas. Exhaust gas recirculation (EGR) reduces NOx (NO, and NO2) production during the combustion of fuel air mixture by reducing flame temperature.
[0003] The existing technology utilizes secondary air injection (SAI), optimized catalytic converter for treating exhaust gases coming out of the combustion chamber. This particular method of injecting secondary air can though decrease the CO component, but above mentioned configuration leads to high NOx emission. Introduction of EGR will reduce NOx to a great extent and also reduce combustion noise. Spark timing optimization with optimized EGR flow rates can reduce NOx while maintaining fuel consumption at current levels. Various mechanisms for EGR to reduce the NOx in the exhaust gases are already known.
[0004] Exhaust Gas Recirculation (EGR) is typically done to reduce the tail pipe emission for meeting the regulation norms. The means of circulating the exhaust gas from exhaust port/manifold to intake port/manifold is done through vacuum operated valves. US11/671,945 this patent deals with electronically controlled throttles for exhausts and air circulation. Electronically controlled EGR has an advantage of precise control of timing and amount of exhaust gas and ease of varying the EGR flow at any point of time without modifying the part, instead modify the program which controls the exhaust gas. At the same time, the electronically controlled EGR has added disadvantage of being more costly and sophisticated equipments are needed to service or change the flow of exhaust gas.
SUMMARY OF THE INVENTION
[0005] The current invention discloses a hand operated throttle with spring loaded mechanically working EGR valve to achieve the exhaust gas circulation from exhaust port/manifold to intake port/manifold. In the present invention, valve actuation is controlled by hand-operated throttle. The flow is controlled by either linear or rotary motion inside the valve. The current invention uses lesser number of parts, which makes it simple to manufacture and assemble. In the present invention, exhaust flow can be easily metered by varying the hole size in rotary type and by providing required taper in linear type valve stem. It doesn’t require any sophisticated program to change the flow rate. Moreover, the profile of the taper portion of the valve stem can be altered as per the requirement of EGR at various throttle levels.
BRIEF DESCRIPTION OF DRAWINGS
[0006] Figure 1illustrates a typical two-wheeler.
[0007] Figure 2 illustrates a typical engine of a two-wheeler.
[0008] Figure 3 illustrates inlet and exhaust ports of a typical cylinder head of engine.
[0009] Figure 4 illustrates an exhaust gas recirculation (EGR) tube.
[00010] Figure 5 illustrates the EGR tube attached to a typical cylinder head.
[00011] Figure 6 illustrates exhaust gas flow from EGR tube to the cylinder head at zero throttle.
[00012] Figure 7 illustrates sectional view of EGR tube at zero throttle.
[00013] Figure 8 illustrates exhaust gas flow from EGR tube to the cylinder head at zero throttle.
[00014] Figure 9 illustrates sectional view of EGR tube at part throttle.
[00015] Figure 10 illustrates exhaust gas flow from EGR tube to the cylinder head at full throttle.
[00016] Figure 11 illustrates sectional view of EGR tube at full throttle.
[00017] Figure 12 illustrates internal construction and functioning of the EGR tube.
DETAILED DESCRIPTION OF THE INVENTION
[00018] In order that those skilled in the art can understand the present invention, the invention is further described below in detail so that various features of the invention thereof proposed here are discernible from the description thereof set out hereunder. However these descriptions and the appended drawings are only used for those skilled in the art to understand the objects, features, and characteristics of the present invention and not to be used to confine the scope and spirit of the present invention.
[00019] In the current invention, the flow of exhaust gases from exhaust port or exhaust manifold to intake port or intake manifold is controlled by a spring-loaded plunger or valve. The flow is regulated such that EGR is available all the time of engine operation other than idle and full throttle position. In addition, the availability of EGR, both in terms of quantity and instances of throttle can be regulated by using corresponding profile. In the current invention, the plunger motion is linear or rotary and is actuated by throttle cable.
[00020] During idling condition, the flow path is blocked by the plunger or the valve. Once the throttle is actuated beyond the idling conditions or into the stage wherein the exhaust flow into intake is required, the flow opens to the intake port. When the throttle reaches the maximum position, or into the stage wherein the exhausts flow into intake is not required in linear type, plunger blocks the flow path. In rotary type, the valve closes the hole through which the EGR flows. This type of mechanism provides controlled flow of EGR. Variable EGR amount can be controlled by providing taper in the plunger or by varying hole sizes in the rotary type valve.
[00021] Figure 1 shows a fuel tank 1, rider seat 2, rear wheel 3, center stand 4, engine 5, front wheel 6, front fork 7, and head lamp 8 in vehicle 10. In general, the combustion of fuels inside the internal combustion engine 5 produces exhaust gases which exits through an exhaust muffler connected to the exhaust port of said engine 5.
[00022] Figure 2 shows engine 5, cylinder block 21, cylinder head 22, magneto cover 23, carburetor assembly 24 and transmission sprocket 25. The cylinder head comprises of the ports functioning as inlet and exhaust inlets. Generally, the intake port is connected to the carburetor assembly 24 to receive the charge for combustion whereas the exhaust port is connected to the exhaust muffler to discharge the exhaust gases.
[00023] Figure 3 shows cylinder head 22, intake port 31; exhaust port 32 and exhaust pipe 33. As per the current invention, the exhaust pipe 33 connects the intake port 31 and the exhaust port 32. The exhaust pipe 33 has an internal construction in such a way that exhaust gases from the exhaust port is channelized from one tube and is fed to the intake port 31.
[00024] Figure 4 illustrates a detailed internal construction of exhaust pipe 33 showing hose clip 36,intake tube 41,exhaust tube 42,valve body 43,valve mechanism 44,valve-body gap 45,stem 46,stem spring 47, hose 48 and plunger 49.The plunger 49 is accommodated inside the hose 48. Plunger 48 is equipped with further portions valve body 43,valve mechanism 44, valve-body gap 45, stem 46 and a portion of which is enveloped by a spring 47. The exhaust tube 42 carries exhaust gases and depending upon the passage defined by the profile on the valve mechanism 44 and valve-body gap 45, an appropriate amount of EGR is channelized and passed to the intake tube 41.
[00025] The more detailed internal construction and functioning of the valve mechanism 44 are illustrated in Figure 12. Figure 12 shows exhaust pipe 33, intake tube 41, exhaust tube 42, stem spring 47, plunger 49, plunger washer 112, and plunger circlip 113 and throttle cable slot 114. A throttle cable is connected to the throttle cable slot 114. When the throttle is varied, correspondingly, the plunger 49 which is enveloped by stem spring 47 moves in the direction of throttle cable movement while compressing said stem spring 47 in-between the plunger washer 112 and the stem 46. During this motion of the plunger 49, there comes an instance when the inlet of the intake tube 41 and the valve-body gap 45 are aligned and the exhaust gas coming from the exhaust tube 43 can enter the intake tube 41.
[00026] Figure 5 shows the sectional view of cylinder head showing the arrangement of the exhaust pipe 33 and its connection therein. Figure 5 shows cylinder head 22, intake port 31, exhaust port 32, exhaust pipe 33, intake tube 41, exhaust tube 42 and hose 48.
[00027] Figure 6 shows the EGR flow under zero throttle condition. Figure 6 shows intake port 31, exhaust port 32, exhaust pipe 33, valve body 43, hose 48 and plunger 49. As illustrated in Figure 6, The EGR coming out of the exhaust port 32 is blocked by the valve mechanism 44 and no EGR is able to reach the intake port 31. The internal mechanism of this EGR blocking during zero throttle is illustrated more clearly in Figure 7.
[00028] Figure 7 further shoes the sectional view of the valve mechanism. Figure 7 further shows exhaust pipe 33,intake tube 41,exhaust tube 42,valve body 43,valve mechanism 44,valve-body gap 45, plunger first wide end portion 71 and a plunger second wide end portion 72. During zero throttle, the valve-body gap 45 is not aligned with the intake tube 41. The plunger first wide end portion 71 and the plunger second wide end portion 72 have a clearance gap that allows the plunger 49 to slide inside the valve body 43 but inhibit the passage of exhaust gases. Furthermore, the profile of the plunger 49 in between said plunger first wide end portion 71 and the plunger second wide end portion 72 can be customized to either initiate or inhibit the EGR (exhaust gas recirculation) through the tube at any desired percentage of wide open throttle (WOT).
[00029] Figure 8 shows the EGR flow under part throttle condition. Figure 8 shows intake port 31, exhaust port 32, exhaust pipe 33 and a hose 48. As illustrated in Figure 8, The EGR coming out of the exhaust port 32 is channelized by the valve mechanism 44 and the EGR is able to reach the intake port 31 by passing through the valve-body gap 45. The internal mechanism of this EGR passage during part throttle is illustrated more clearly in Figure 9.
[00030] Figure 9 further shoes the sectional view of the valve mechanism. Figure 9 shows exhaust pipe 33,intake tube 41,exhaust tube 42,valve body 43,valve mechanism 44,valve-body gap 45,plunger first wide end portion 71,plunger second wide end portion 72 and exhaust flow direction 91. During part throttle, the valve-body gap 45 is aligned with the intake tube 41. The plunger first wide end portion 71 and the plunger second wide end portion 72 have enough clearance gap that allows the plunger 49 to slide inside the valve body 43 and also for the passage of exhaust gases.
[00031] Figure 10 shows the EGR flow under full throttle condition. Figure 10 shows intake port 31, exhaust port 32, exhaust pipe 33 and hose 48. As illustrated in Figure 10, the EGR coming out of the exhaust port 32 is blocked by the valve mechanism 44 and no EGR is able to reach the intake port 31. The internal mechanism of this EGR blocking during full throttle is illustrated more clearly in Figure 11.
[00032] Figure 11 further shoes the sectional view of the valve mechanism. Figure 11 shows exhaust pipe 33, intake tube 41,exhaust tube 42,valve body 43,valve mechanism 44,valve-body gap 45,plunger first wide end portion 71 and plunger second wide end portion 72. During full throttle, the valve-body gap 45 is not aligned with the intake tube 41. The plunger first wide end portion 71 and the plunger second wide end portion 72 have very minimal clearance gap that allows the plunger 49 to slide inside the valve body 43 but to inhibit the passage of exhaust gases. Furthermore, as described earlier, the profile of the valve mechanism 44 in between said plunger first wide end portion 71 and the plunger second wide end portion 72 can be customized to either initiate or inhibit the EGR (exhaust gas recirculation) through the tube at any desired throttle percentage near the wide open throttle (WOT) stage.
[00033] Figure 12 shows exhaust pipe 33, intake tube 41, exhaust tube 43, stem spring 47, plunger 49, plunger washer 112, and plunger circlip 113 and throttle cable slot 114. A throttle cable is connected to the throttle cable slot 114. When the throttle is varied, correspondingly, the plunger 49 which is enveloped by stem spring 47 moves in the direction of throttle cable movement while compressing said stem spring 47 in-between the plunger washer 112 and the stem 46. During linear motion of the plunger 49, at the instances when the inlet of the intake tube 41 and the valve-body gap 45 are aligned, the exhaust gas coming from the exhaust tube 43 is channelized into the intake tube 41. The EGR flow is restricted during the linear motion of the plunger 49, at the instances when the intake tube 41 and first wide end portion (71) or second wide end portion (72) are aligned, at zero throttle and full throttle respectively.
,CLAIMS:We claim:
1. A system of exhaust gas recirculation (EGR) for an internal combustion engine (5); said internal combustion engine comprising:
an intake port (31); said intake port receiving air fuel mixture for combustion;
an exhaust port (32) which provides a passage for exhaust gases;
an exhaust pipe (33) comprising an intake tube (41) and an exhaust tube (42), the intake tube (41) connected to said intake port (31) and the exhaust tube (42) connected to said exhaust port (32);
characterized in that:
the exhaust pipe (33) comprises of a valve body (43) in-between said intake tube (41) and the exhaust tube (42), the valve body (43) comprises of a valve mechanism (44) to control the amount and instances of EGR introduction through said intake tube (41) inside said intake port (31) based on actuation of throttle hose (48).
2. The system of exhaust gas recirculation for an internal combustion engine as claimed in claim 1 wherein valve-body gap (45) of the valve mechanism (44) in said EGR pipe (33) aligns with said intake tube (41) to activating the EGR flow.

3. The system of exhaust gas recirculation for an internal combustion engine as claimed in claim 1 wherein said valve-body gap (45) is aligned with said intake tube (41) during part throttle.

4. The system of exhaust gas recirculation for an internal combustion engine as claimed in claim 1 wherein said valve-body gap (45) is aligned with a plunger first wide end portion (71) during zero throttle.

5. The system of exhaust gas recirculation for an internal combustion engine as claimed in claim 1 wherein said valve-body gap (45) is aligned with a plunger second wide end portion (72) during full throttle.

6. The system of exhaust gas recirculation for an internal combustion engine as claimed in claim 1 or claim 3 wherein the EGR circulation is present during part throttle.
7. The system of exhaust gas recirculation for an internal combustion engine as claimed in claim 1 or claim 4 or claim 5 wherein the EGR circulation is restricted during zero throttle and full throttle.