Claims:I Claim:

1. An exhaust charging pump (100) for an exhaust gas recirculation (EGR) system,

said exhaust charging pump (100) comprising at least a first inlet (102) and a second inlet (104), and at least one outlet (106);

said first inlet (102) in flow communication with exhaust from a first path (108) of said EGR system, and said second inlet (104) in flow communication with exhaust mixed with air from a second path (110) of said EGR system; and

exhaust received in said first inlet (102) provides pulsation for compressing said exhaust charging pump (100) for delivery of said exhaust mixed with air into said outlet (106), said outlet 106 in flow communication with inlet of said engine.

2. An exhaust gas recirculation (EGR) system (200), comprising at least,

an exhaust path (202) from an engine, said exhaust path 202 opening into at least a first path (108) and a second path (110), characterized in that

an exhaust charging pump (100) comprising at least a first inlet (102) and a second inlet (104), and at least one outlet (106);

said first inlet (102) in flow communication with exhaust from said first path (108), and said second inlet (104) in flow communication with exhaust mixed with air from said second path (110); and

exhaust received in said first inlet (102) provides pulsation for compressing said exhaust charging pump (100) for delivery of said exhaust mixed with air into said outlet (106), said outlet (106) in flow communication with inlet of said engine.
, Description:Field of the invention
[0001] This invention relates to the field of exhaust gas recirculation system.
Background of the invention
[0002] Exhaust gas recirculation for engines is required in order to reduce pollutants and particulate matter from exhaust before the exhaust is sent to the atmosphere. In a conventional EGR system, the exhaust gas passes through a cooler and a flow regulating valve before mixing with air and reaching the inlet of the engine. In case of engines with smaller capacity, like, for example, single cylinder naturally aspirated engines, there is a need to increase the power produced in the engine. Since smaller capacity engines are generally used for low cost application, the introduction of a supercharger to increase the power generated by the engine, might increase the overall cost of the vehicle. Moreover, if a supercharger is directly exposed to exhaust then it would lead to issues like, deposition of soot in the components of the supercharger, leading to decrease in efficiency over a period of time. However if the available exhaust is utilized in a manner such that it can used to increase the density of air supplied to the engine, then it would increase the power of the engine, decrease specific fuel consumption and also reduce emissions. The subject of interest here is about making use of the available exhaust and channeling the exhaust in a manner so as to increase the power produced in the engine.
[0003] Prior art patent application DE-102012209230 discloses an internal combustion engine for motor car, has AGR pump conveying exhaust gas from exhaust pipe into air inlet, where gas is injected into air inlet with tangential direction component at mixture location before entering compressor. The engine has a compressor for compressing combustion air flowing in an air inlet. A suction side of an AGR pump is connected optionally with an exhaust pipe or the air inlet. The AGR pump conveys exhaust gas from the exhaust pipe into the air inlet upstream of the compressor. The gas conveyed from the AGR pump is injected into the air inlet with a tangential direction component with respect to direction of flow of the combustion air at a mixture location before entering the compressor. The AGR pump comprises an electric drive. The combustion engine works based on Otto- or diesel engines processes.

Brief description of the accompanying drawing
[0004] Different modes of the invention are disclosed in detail in the description and illustrated in the accompanying drawing:

[0005] FIG. 1 illustrates an exhaust charging pump for an Exhaust charge recirculation (EGR) system; and

[0006] FIG. 2 illustrates an Exhaust charge recirculation (EGR) system.

Detailed description of the embodiments
[0007] FIG. 1 illustrates an exhaust charging pump 100 for an Exhaust charge recirculation (EGR) system. The exhaust charging pump 100 comprises at least a first inlet 102 and a second inlet 104, and at least one outlet 106. The first inlet 102 is in flow communication with exhaust from a first path 108 of the EGR system, and the second inlet 104 is in flow communication with exhaust mixed with air from a second path 110 of the EGR system. The exhaust received in the first inlet 102 provides pulsation for compressing the exhaust charging pump 100 for delivery of the exhaust mixed with air into the outlet 106. The outlet 106 is in flow communication with inlet of the engine.
[0008] FIG. 2 illustrates an Exhaust charge recirculation (EGR) system 200. The EGR system 200 comprises at least an exhaust path 202 from an engine, opening into at least a first path 108 and a second path 110. The EGR system is characterized in having an exhaust charging pump 100 comprising at least a first inlet 102 and a second inlet 104, and at least one outlet 106. The first inlet 102 is in flow communication with exhaust from the first path 108, and the second inlet 104 is in flow communication with exhaust mixed with air from the second path 110. The exhaust received in the first inlet 102 provides pulsation for compressing the exhaust charging pump 100 for delivery of the exhaust mixed with air into the outlet 106. The outlet 106 is in flow communication with inlet of the engine. In an engine, pulsation is caused due to opening and closing of intake and exhaust valves and the reciprocating action of the piston.

[0009] The working of the above mentioned EGR system with respect to exhaust charging pump 100 will now be described in further detail. The exhaust charging pump 100 is adapted to perform at least two important functions. Firstly, suck the exhaust gas from the exhaust path 202 by creating a pressure difference between the exhaust charging pump 100 and the second path 110. Secondly, compress the exhaust, through pulsation of the exhaust charging pump 100, so as to deliver the charged exhaust to the inlet of the engine. During working of the engine, the exhaust generated due to combustion flows through the exhaust path 202 to reach first path 108 and the second path 110. The second path 110 may have a cooler to cool the exhaust and a control valve to control the rate of flow of exhaust into the inlet of the exhaust charging pump 100. Alternately, the control valve may be avoided, by using the sucking effect of the exhaust charging pump 100. The exhaust present in the second path 110 mixes with air. The second inlet 104 of the exhaust charging pump 100 has an inlet valve. The pressure available in exhaust mixed with air, causes the inlet valve to open and the space available in the exhaust charging pump 100 is filled with the above mentioned exhaust and air. The exhaust mixed with air in the exhaust charging pump 100 will now be referred to as an “exhaust charge”. Now, in order to compress the exhaust charge, a certain amount of energy has to be delivered. This is achieved through pulsation for compressing the exhaust charging pump 100. The pulsation concept will now be described in further detail.

[00010] The exhaust charging pump 100 has a flexible elastic membrane. The exhaust present in the first flow path provides pulsation for compressing said exhaust charging pump 100. In other words the energy available in the exhaust is transferred to the exhaust charge present in the exhaust charging pump 100 via the elastic corpus. The exhaust charge now has energy that is sufficient enough to open an outlet valve present in outlet 106. The outlet 106 is in flow communication with the inlet of the engine. The exhaust charge is given as an input to the fuel entering the inlet of the engine, resulting in combustion in the engine. Once the exhaust charge has been delivered to the engine, the exhaust charging pump 100 expands and is now in able to receive the exhaust charge for the next cycle of compression to happen. It should noted that through alternate compression and expansion of the elastic membrane, the exhaust charge is sucked into the exhaust charging pump 100, compressed and delivered as an input to the inlet of the engine. Once the energy from the exhaust is delivered to the exhaust charge present in the exhaust charge pump 100, the exhaust present in the first path 108 reaches the silencer. A fresh volume of exhaust then reaches the first path 108 for pulsation to happen again. By using the sucking effect of the exhaust charging pump, the EGR flow rate can be increased in the EGR system 200. Also, the working of the exhaust charging pump is such that it is in sync with the engine cycle, thereby ensuring that the exhaust charge is delivered to the inlet of the engine, only when the fuel enter the engine.

[00011] The above mentioned exhaust charging pump 100 can be easily serviced for removing dust, soot and other particulate matter present in the exhaust. With the proposed exhaust charging pump 100, we now have a simple mechanism to supercharge engines like single cylinder engines, thereby boosting their efficiencies. Also, by making use of exhaust charging pump 100 to suck more amount of exhaust gas, NOx emissions can be significantly reduced.

[00012] It should be understood that embodiments explained in the description above are only illustrative and do not limit the scope of this invention in terms of the type the engine used and the configuration of the EGR system. Many such embodiments and other modifications and changes in the embodiment explained in the description are envisaged. The scope of the invention is only limited by the scope of the claims.