DESC:FIELD OF INVENTION
[0001] The present invention relates to an internal combustion engine and more particularly to a pollution controlling mechanism for the engine.

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, few are harmful and 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 vacuum operated, spring and diaphragm loaded 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 vacuum created in the intake pipe. The flow is controlled by a control valve mechanism incorporated inside the EGR valve. In the present invention, exhaust flow can be easily metered by calibrating the opening of the EGR valve with respect to the range of vacuum created inside the intake chamber. It does not require any sophisticated program to change the flow rate. Moreover, the valve portion of the EGR valve stem can be altered to get a more range for calibration and more accuracy for EGR at various desired instances of intake vacuum.
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 control valve mechanism of the EGR system.
[00010] Figure 5 illustrates the EGR system attached to a typical cylinder head.
[00011] Figure 6 illustrates exhaust gas flow from EGR tube to the intake port at zero throttle.
[00012] Figure 7 illustrates exhaust gas flow from EGR tube to the intake port at part throttle.
[00013] Figure 8 illustrates exhaust gas flow from EGR tube to the intake port at full throttle.
[00014] Figure 9 illustrates sectional view of EGR control valve at zero throttle.
[00015] Figure 10 illustrates sectional view of EGR control valve at part throttle.
[00016] Figure 11 illustrates sectional view of EGR control valve at full throttle.
DETAILED DESCRIPTION OF THE INVENTION
[00017] 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.
[00018] In the current invention, a spring-loaded plunger or valve controls the flow of exhaust gases from exhaust port or exhaust manifold to intake port or intake manifold. 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 of the shaft valve. In the current invention, the plunger motion is linearly actuated based on the vacuum sensed by the diaphragm of an EGR control valve.
[00019] During idling condition, a valve seat second end 46 and operating shaft second stopper 47 block the flow path. Once the combustion starts and vacuum decreases, a operating shaft first stopper 44 is actuated and moved towards a valve seat first end 45, thus creating a gap between the operating shaft second stopper 47 and the valve seat second end 46. EGR is required 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, operating shaft first stopper 44 touches the valve seat first end 45 and thus thereby blocks the passage of EGR into the intake tube 30. This type of mechanism provides controlled flow of EGR.
[00020] 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 headlamp 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 the engine 5. Though for illustration purposes, a two-wheeled motorcycle is shown, this invention is applicable to any internal combustion engine.
[00021] Figure 2 shows engines 5, intake manifold 12, cylinder block 21, cylinder head 22, and intake pipe 23 and exhaust port 25. Though for illustration purposes, a geared two wheeled motorcycle engine is shown, this invention is also applicable to an internal combustion engine with CVT type transmission.
[00022] Figure 3 shows cylinder block 21, intake pipe 23, intake port 24, exhaust port 25, vacuum tube 26, exhaust tube 27, valve top body 28, EGR valve 29 and tube intake assembly 30. The air fuel mixture enters the internal combustion engine from the intake manifold 12, travels through the intake pipe 23 and enters the intake port 24. The combustion of the fuel takes place inside the cylinder and exhaust gases leave the cylinder from the exhaust port 25. An exhaust tube 27 has been introduced which connects the exhaust port 25 to the EGR valve 29. The outlet of EGR valve 29 is further connected to a tube intake assembly 30, through which a controlled amount of exhaust gases are recirculated to the intake port 24. The EGR valve 29 controls the amount of EGR fed to the intake port 24. The functioning of EGR valve 29 is further dealt in more detail further in the description. The EGR valve 29 gets its input to control the EGR amount from the vacuum generated inside the intake port through a diaphragm mechanism inside the valve top body 28. According to an embodiment of the present invention, the diaphragm is sandwiched to the valve top body 28 and hence whenever the spring compresses or expands, the diaphragm moves accordingly. The valve top body is internally connected to the intake pipe 23 through a vacuum tube 26. Hence, the vacuum generated inside the intake port is transferred to the diaphragm inside the valve top body 28 through the vacuum tube 26 and a shaft attached to the diaphragm controls the flow of EGR back to the tube intake assembly 30.
[00023] Figure 4 shows intake pipe 23, exhaust port 25, vacuum tube 26, exhaust tube 27,valve top body 28, valve 29, tube intake assembly 30,dual way operating shaft 41, vacuum cover 42, spring 43, operating shaft first stopper 44, valve seat first end 45, valve seat second end 46 and operating shaft second stopper 47. The vacuum tube 26, valve top body 28, valve 29, tube intake assembly 30 and exhaust tube 27 form the essential elements of the EGR system according to the present invention. The dual way-operating shaft 41 is fastened to said deflectable valve top body (28) through a fastener (49). The exhaust tube 27 is connected to the exhaust port 25 to draw the exhaust gases and the vacuum tube 26 transfers the equivalent force to a diaphragm inside the valve top body 28. The diaphragm is further connected to a valve stem 41 that has a stopper and a vane mechanism to allow or to inhibit the flow of exhaust gases through the tube intake assembly 30.
[00024] Figure 5 illustrates the EGR system disclosed in Figure 4 attached to a typical cylinder head. Figure 5 shows intake port 24, exhaust port 25, vacuum tube 26,exhaust tube 27, tube intake assembly 30, dual way operating shaft 41, vacuum cover 42, operating shaft first stopper 44, valve seat first end 45, valve seat second end 46 and the operating shaft second stopper 47. Figure 5 illustrates the EGR flow from the exhaust port to the intake port. EGR flow under idle condition, part throttle condition and full throttle condition would be described herein further.
[00025] Figure 6 illustrates exhaust gas flow from EGR tube to the intake port at zero throttle level. Figure 6 shows intake port 24, exhaust port 25, vacuum tube 26,exhaust tube 27, valve top body 28, tube intake assembly 30, dual way operating shaft 41, spring 43, operating shaft first stopper 44,valve seat first end 45, valve seat second end 46 and the operating shaft second stopper 47. In idle condition, the vacuum created inside the intake chamber is more which is transmitted to the diaphragm 28 through a pipe 26 connected to the intake pipe 23. The larger vacuum inside the intake chamber results in the diaphragm getting deflected towards the intake pipe 23 resulting in operating shaft 41’s movement towards the diaphragm hence blocking the valve seat second end 46 with the operating shaft second stopper 47. Thus, there is no EGR, which can flow to the tube intake assembly 30. Hence no EGR is allowed inside the intake chamber through the tube intake assembly 30 during the idling condition.
[00026] Figure 7 illustrates exhaust gas flow from EGR tube to the intake port at part throttle. Figure 7 shows intake port 24, exhaust port 25, vacuum tube 26, exhaust tube 27,valve top body 28, tube intake assembly 30,dual way operating shaft 41, spring 43, operating shaft first stopper 44, valve seat first end 45, valve seat second end 46 and operating shaft second stopper 47. In part throttle condition, the vacuum created inside the intake chamber is decreased a little, which is transmitted to the diaphragm 28 through a pipe 26 connected to the intake pipe 23. The reduced vacuum inside the intake chamber results in the diaphragm getting deflected away from the intake pipe 23 resulting in operating shaft 41’s movement away from the diaphragm hence opening the valve seat second end 46 with the operating shaft second stopper 47. Thus, there is a small amount of EGR, which can flow to the tube intake assembly 30. Hence, a controlled amount of EGR is allowed inside the intake chamber through the tube intake assembly 30 during the part throttle condition.
[00027] Figure 8 illustrates exhaust gas flow from EGR tube to the intake port at full throttle condition. Figure 8 again shows intake port 24, exhaust port 25, vacuum tube 26, exhaust tube 27, valve top body 28, tube intake assembly 30, dual way operating shaft 41, spring 43, operating shaft first stopper 44, valve seat first end 45, valve seat second end 46 and operating shaft second stopper 47. At full throttle condition, the vacuum decreases to a level which pushes the diaphragm further more towards the operating shaft 41 till the operating shaft first stopper 44 encounters the valve seat first end 45 thereby sealing the passage of EGR flow from the exhaust tube 27 to the tube intake assembly 30.
[00028] Figure 9 illustrates the EGR valve functioning during exhaust gas flow from EGR tube to the intake port at zero throttle. Figure 9 shows intake pipe 23, exhaust port 25, valve top body 28, tube intake assembly 30, dual way operating shaft 41,spring 43, operating shaft first stopper 44, valve seat first end 45, valve seat second end 46, operating shaft second stopper 47, vacuum 91. The valve seat second end 46 sits on the operating shaft second stopper 47 thereby completely sealing the flow passage of EGR from the exhaust tube 27 to the tube intake assembly 30.
[00029] Figure 10 shows intake pipe 23, exhaust port 25, valve top body 28, tube intake assembly 30, dual way operating shaft 41,spring 43, operating shaft first stopper 44, valve seat first end 45, valve seat second end 46, operating shaft second stopper 47, vacuum 91. In the part throttle condition, the valve seat first end 45 or the valve seat second end 46 is neither in contact with the operating shaft first stopper 44 nor in contact with the operating shaft second stopper 47. Hence, the passage for EGR flow is open thereby the flow passage of EGR from the exhaust tube 27 to the tube intake assembly 30 is maintained.
[00030] Figure 11 shows intake pipe 23, exhaust port 25, valve top body 28, tube intake assembly 30, dual way operating shaft 41,spring 43, operating shaft first stopper 44, valve seat first end 45, valve seat second end 46, operating shaft second stopper 47, vacuum 91. Under full throttle condition, the valve seat first end 44 sits on the operating shaft first stopper 45 thereby completely sealing the flow passage of EGR from the exhaust tube 27 to the tube intake assembly 30.
[00031] The valve shaft 41 comprises mainly of the operating shaft first stopper 44, valve seat first end 45, valve seat second end 46 and operating shaft second stopper 47. The portion of the valve shaft 41 between the operating shaft first stopper 44 and operating shaft second stopper 47 can be given a desired shape to provide continuous regulated flow of EGR during the part throttle condition.
,CLAIMS:We claim:
1. A system of exhaust gas recirculation (EGR) for an internal combustion engine (5); the internal combustion engine comprising:
an intake port (24) connected to an intake pipe (23) to receive air fuel mixture for combustion and a tube intake assembly (30) to receive an exhaust gas recirculation;
an exhaust port (25) connected to an exhaust tube (27) with a provision made for tapping EGR;
an EGR valve (29) calibrated to control the flow of exhaust gases recirculated into the intake port (24) of the engine (5);
wherein the EGR valve (29) receives an actuating signal from a vacuum tube (26) connected to intake pipe (23) and exhaust gases through an exhaust tube (27); and
the EGR valve (29) releases a calculated amount of exhaust gases into the intake port (24) based on a pre-calibrated value of vacuum at the tube intake assembly (30).
2. The system of exhaust gas recirculation (EGR) for the internal combustion engine (5) as claimed in claim 1 wherein the EGR valve (29) comprises of a deflectable valve top body (28).
3. The system of exhaust gas recirculation (EGR) for the internal combustion engine (5) as claimed in claim 1 or claim 2 wherein the deflectable valve top body (28) is made up of an elastic material.
4. The system of exhaust gas recirculation (EGR) for the internal combustion engine (5) as claimed in claim 1 or claim 2 wherein the deflectable valve top body (28) is pneumatically actuated.
5. The system of exhaust gas recirculation (EGR) for the internal combustion engine (5) as claimed in claim 1 or claim 2 wherein the deflectable valve top body (28) is disposed in between a spring (43) and a dual way operating shaft 41.
6. The system of exhaust gas recirculation (EGR) for the internal combustion engine (5) as claimed in claim 1 or claim 2 wherein the spring (43) is disposed in between said deflectable valve top body (28) and a dual way operating shaft 41.
7. The system of exhaust gas recirculation (EGR) for the internal combustion engine (5) as claimed in claim 1 or claim 2 or claim 5 wherein the dual way operating shaft 41 is fastened to said deflectable valve top body (28) through a fastener (49).
8. The system of exhaust gas recirculation (EGR) for the internal combustion engine (5) as claimed in claim 1 or claim 2 or claim 5 wherein the spring (43) at a first end is fastened to EGR valve (29) casing and a second end is fastened to said deflectable valve top body (28) through a fastener (49).
9. The system of exhaust gas recirculation (EGR) for the internal combustion engine (5) as claimed in claim 1 or claim 2 or claim 5 wherein fastener (49) is used to fasten the spring (43), the deflectable valve top body (28) and the dual way operating shaft 41.