CLIAMS:We Claim:
1. A gear arrangement (100) for controlling an EGR valve (135) and an air throttle valve (130) in an internal combustion engine, said gear arrangement (100) comprising:
a first gear member (105), a second gear member (110), a third gear member (115) and a fourth gear member (120),
said second gear member (110) and said third gear member (115) are connected to a motor (125) through a common shaft (122),
said second gear member engaged to said first gear member (105) and said first gear member engages with an air throttle valve (130) through a first shaft (140); and
said third gear member 115 engaged to said fourth gear member (120), said fourth gear member (120) engages with an EGR valve (135) through a second shaft (145).

2. The gear arrangement (100) as claimed in claim 1, wherein said second gear member (110) engages said first gear member (105) for driving the first gear member (105).

3. The gear arrangement (100) as claimed in claim 1, wherein said third gear member (115) engages said fourth gear member (120) for driving the fourth gear member (120).

4. A device for controlling an EGR valve (135) and an air throttle valve (130) in an internal combustion engine, the device comprising:
a motor (125); and
a gear arrangement (100) driven by a motor (125) through a common shaft (122) connecting said gear arrangement (100) and said motor (125), said gear arrangement (100) comprises a first gear member (105), a second gear member (110), a third gear member (115) and a fourth gear member (120);
said second gear member (110) and said third gear member (115) are connected to said motor (125) through said common shaft (122);
said second gear member engaged to said first gear member (105) and said first gear member engages with an air throttle valve (130) through a first shaft (140); and
said third gear member (115) engaged to said fourth gear member (120), said fourth gear member (120) engages with an EGR valve (135) through a second shaft (145).

5. The device as claimed in claim 4, wherein diameter of said second gear member (110) and diameter of said third gear member (115) are unequal.

6. The device as claimed in claim 4, wherein profile of said second gear member (110) is such that gear teeth is present on at least a part of said second gear member (110) for operating said air throttle valve (130) at different engine operating conditions.

7. The device as claimed in claim 4, wherein profile of said third gear member (115) is such that gear teeth is present on at least a part of said third gear member (115) for operating said EGR valve (135) at different engine operating conditions. ,TagSPECI:The following specification particularly describes the invention and the manner in which it is to be performed.

Field of the invention
[001] This invention relates to a device for controlling an EGR valve and an air throttle valve in an internal combustion engine.

Background of the invention
[002] An air throttle valve located at an inlet manifold of an internal combustion engine controls quantity of intake air entering into the internal combustion engine. The air throttle valve operates based on engine operating conditions so that optimal combustion occurs in the internal combustion engine. A dedicated actuator rotates a shaft of the air throttle valve. Based on degree of rotation of the shaft, the air throttle valve is controlled. Similarly, for controlling Nox emission, exhaust gas is recirculated back into the inlet manifold. An EGR valve is used for controlling quantity of exhaust gases entering into the engine cylinder. Another dedicated actuator rotates a shaft of the EGR valve for controlling quantity of exhaust gases.

[003] According to a WIPO application numbered WO-2007089771, a technique of utilizing a single actuator for controlling both the air throttle valve and the EGR valve is disclosed. The single actuator actuates the EGR valve between a closed position, an intermediate position, and an open position, and a throttle valve between an open position and a closed position. The EGR valve is installed with an EGR line while the throttle valve is installed within an exhaust conduit in which the EGR line is connected to the exhaust conduit.

Brief description of the accompanying drawings
[004] Figure 1 illustrates a device for controlling an EGR valve and an air throttle valve in an internal combustion engine; and
[005] Figure 2 shows a gear arrangement for controlling an EGR valve and an air throttle valve in an internal combustion engine, in accordance with an embodiment.

Detailed description
[006] Figure 1 illustrates a device for controlling an EGR valve and an air throttle valve in an internal combustion engine.

[007] The device for controlling an EGR valve 135 and an air throttle valve 130 comprises a motor 125 and a gear arrangement 100 that is driven by the motor 125 through a common shaft 122 connecting the gear arrangement 100 and the motor 125. The gear arrangement 100 comprises a first gear member 105, a second gear member 110, a third gear member 115 and a fourth gear member 120. The second gear member 110 and the third gear member 115 are connected to the motor 125 through the common shaft 122. The second gear member 110 is engaged to the first gear member 105 and the first gear member 105 is engaged to the air throttle valve 130 through a first shaft 140. The third gear member 115 engaged to the fourth gear member 120, the fourth gear member 120 engages with an EGR valve 135 through a second shaft 145.

[008] The gear arrangement 100 comprises four gears, the first gear member 105, the second gear member 110, the third gear member 115 and the fourth gear member 120. The second gear member 110 and the third gear member 115 are connected to a common shaft 122 of a motor 125. The motor 125 is driven by current supplied by an electronic control unit. The second gear member 110 and the third gear member 115 have unequal diameters for controlling the air throttle valve 130 and the EGR valve 135 at various combinations of percentage openings. In one embodiment, the diameter of the second gear member 110 is smaller than the diameter of the third gear member 115. The second gear member 110 drives the first gear member 105 and the third gear member 115 drives the fourth gear member 120. Also, the second gear member 110 and the third gear member 115 do not consist of gear teeth throughout the circumference. Presence of the gear teeth in at least one part of the second gear member 110 and the third gear member 115 are calibrated initially based on different engine operating conditions for which the air throttle valve 130 or the EGR valve 135 or both are required to be operated.

[009] The second gear member 110 engages with the first gear member 105 for controlling the air throttle valve 130 and the third gear member 115 engages with the fourth gear member 120 for controlling the EGR valve 135. The air throttle valve 130 and the EGR valve 135 may be a butterfly valve that is operated by a shaft or any other valve that is operated by a shaft. The first gear member 115 that is driven by the second gear member 110 operates the air throttle valve 130 through a first shaft 140 that is connected to both the first gear member 110 and the air throttle valve 130. Similarly, the fourth gear member 120 that is driven by the third gear member 115 operates the EGR valve 135 through a second shaft 145 that is connected to both the fourth gear member 120 and the EGR valve 135.

[0010] The electronic control unit supplies current to the motor 125 so that the motor 125 can drive the second gear member 110 and the third gear member 115 through the common shaft 122. The current supplied to the motor 125 is based on an engine operating condition. Once the current is supplied, the motor 125 begins to rotate thereby rotating the common shaft 122. Once the common shaft 122 begins to rotate, the second gear member 110 and the third gear member 115 begin to rotate.

[0011] The second gear member 110 now drives the first gear member 105 and the third gear member 115 drives the fourth gear member 120. The amount of time the second gear member 110 drives the first gear member 105 or the degree of rotation of the second gear member 110 for driving the first gear member 105 defines the percentage opening of the air throttle valve 130. The driving of the first gear member 105 by the second gear member 110 depends on the current supplied by the electronic control unit.

[0012] Similarly, the amount of time the third gear member 115 drives the fourth gear member 120 or the degree of rotation of the third gear member 115 for driving the fourth gear member 120 defines the percentage opening of the EGR valve 135. The driving of the fourth gear member 120 by the third gear member 115 depends on the current supplied by the electronic control unit.

[0013] In some cases, the current supplied to the motor 125 may be such that either the second gear member 110 drives the first gear member 105 and thereby operate only the air throttle valve 130 or the third gear member 115 drives the fourth gear member 120 thereby operating only the EGR valve 135. In such cases, position of the second gear member 110 and the third gear member 115 are calibrated such that either the second gear member 110 drives the first gear member 105 or the third gear member 115 drives the fourth gear member 120. In another case, both the air throttle valve 130 and the EGR valve 135 are operated simultaneously based on the engine operating condition. In such cases the second gear member 110 drives the first gear member 105 and the third gear member 115 drives the fourth gear member 120 at the same time. The percentage opening of each valve is defined by the current supplied by the electronic control unit to the second gear member 110 and the third gear member 115.

[0014] For operating the valves, different engine operating conditions is stored in a memory of the electronic control unit. Also, the valve that is required to be opened at different engine operating condition is also stored in the memory of the electronic control unit. Further, the percentage opening of each valve for each engine operating condition is also stored in the memory of the electronic control unit. Hence, different percentage openings for each valve are stored for different engine operating conditions. Furthermore, a current value for opening each valve at each percentage opening is also stored in the memory of the electronic control unit. Therefore different current values are used for opening each valve at different percentage openings.

[0015] The operation of air throttle valve 130 and the EGR valve based on engine operating conditions is explained in the form of different scenarios in the below paragraphs for the purpose of clear understanding of the disclosure.

[0016] In one case, the engine operating condition may be such that only air throttle valve 130 is required to be opened by a particular percentage value, for example 80%. In such a case, the electronic control unit supplies a particular current, for example, current I1 to the motor 125. This current is stored in the memory of the electronic control unit as described in the above paragraph. Upon supplying the current I1 to the motor 125, it begins to rotate the common shaft 122 thereby rotating the second gear member 110 and the third gear member 115. The position of the second gear member 110 is such that when current I1 is supplied to the motor 125, the second gear member 110 meshes with the first gear member 105 for operating the air throttle valve 130 such that the air throttle valve 130 opens by 80%. Also, since only air throttle valve 130 is required to be open, the position of the third gear member 115 when current I1 is supplied to the motor 125 is such that the portion of the third gear member 115 that does not include the gear teeth is in contact with the fourth gear member 120 so that the fourth gear member 120 does not rotate, thereby the EGR valve 135 is not operated at this engine operating condition.

[0017] Similarly if the air throttle valve 130 is required to be opened by a different percentage value then the electronic control unit will supply a corresponding current value to the motor 125 so that the second gear member 110 drives the first gear member 105 to an extent upto which that percentage value of the air throttle valve 130 is opened. However, the current value will be such that the EGR valve 135 is not operated.

[0018] The air throttle valve 130 is also configured to provide a feedback signal to the electronic control unit. A position sensor located in the air throttle valve 130 is used for providing the feedback signal. The feedback signal indicates if the air throttle valve 130 is opened to a desired percentage opening. In cases where the desired percentage opening is not acquired then in such cases the electronic control unit is adapted to alter the current that is supplied to the motor 125 based on the feedback signal until the air throttle valve 130 is opened to the desired percentage opening.

[0019] In another case, the engine operating condition may be such that only EGR valve 135 is required to be opened for a particular percentage value, for example 20%. In such cases, the electronic control unit supplies a particular current, for example I2 to the motor 125. Upon receiving the current I2, the motor 125 begins to drive the second gear member 110 and the third gear member 115. When the motor 125 drives the second gear member 110 and the third gear member 115 at current I2, the position of the third gear member 115 is such that it meshes with the fourth gear member 120 thereby operating the EGR valve 135. Also, when the motor 125 is driven by the current I2, the position of the second gear member 110 is such that the portion of the second gear member 110 that does not include the gear teeth is in contact with the first gear member 105 so that the first gear member 105 does not move and thereby the air throttle valve 130 is not operated at this engine operating condition.

[0020] If the EGR valve 135 is required to be open for a different percentage value then the electronic control unit will supply a corresponding current value to the motor 125 so that the third gear member 115 drives the fourth gear member 120 to an extent upto which that percentage value of the EGR valve 135 is opened. However, the current value supplied will be such that the air throttle valve 130 is not operated at this engine operating condition.

[0021] The EGR valve 135 is configured to provide a feedback signal to the electronic control unit. A position sensor located in the EGR valve 135 provides such a feedback signal. The feedback signal indicates if the EGR valve 135 is opened to the desired percentage opening. In cases where the desired percentage opening is not acquired then in such cases the electronic control unit is adapted to alter the current that is supplied to the motor 125 based on the feedback signal until the EGR valve 135 is opened to the desired percentage opening.

[0022] In yet another case, the engine operating condition may be such that both air throttle valve 130 and EGR valve 135 is required to be open. The air throttle valve 130 may be required to be opened by 50% and the EGR valve 135 may be required to be opened by 30%. In such cases, the electronic control unit determines that both the air throttle valve 130 and the EGR valve 135 is required to be opened by 50% and 30% respectively. Further, the electronic current determines current value that is required to be supplied for operating the air throttle valve 130 to be opened by 50% and the EGR valve 135 to be opened by 30%. Let the current value for opening the air throttle valve 130 by 50% and the EGR valve 135 by 30% be I3. The current I3 is supplied to the motor 125. Similarly, current values that are required to be supplied to the motor 125 for different combinations of percentage openings of the air throttle valve 130 and the EGR valve 135 are stored in the memory of the electronic control unit. The motor 125 upon receiving current I3 rotates the second gear member 110 and the third gear member 115 through the common shaft 122. The second gear member 110 now meshes with the first gear member 105 and the first gear member 105 now rotates the first shaft 140 that is connected to the air throttle valve 130. The second gear member 110 drives the first gear member 105 until the air throttle valve 130 opens by 50%. Similarly, at current I3, the third gear member 115 meshes with the fourth gear member 120 and drives the fourth gear member 120. The fourth gear member 120 now rotates the second shaft 145 until the EGR valve 135 opens by 30%. The position of the second gear member 110, so that the second gear member 110 drives the first gear member 105 for opening the air throttle valve 130 by 50% at current I3 is initially calibrated. Similarly, the position of the third gear member 115, so that the third gear member 115 drives the fourth gear member 120 for opening the EGR throttle valve by 30% at current I3 is obtained because of initial calibration.

[0023] Figure 2 shows a gear arrangement 100 for controlling an EGR valve and an air throttle valve in an internal combustion engine, in accordance with an embodiment.

[0024] The device comprises a gear arrangement 100. The gear arrangement 100 comprises a first gear member 105, a second gear member 110, a third gear member 115 and a fourth gear member 120. The second gear member 110 and the third gear member 115 are connected to a motor 125 through a common shaft 122. The second gear member is engaged to the first gear member 105 and the first gear member engages with an air throttle valve 130 through a first shaft 140 and the third gear member 115 is engaged to the fourth gear member 120. The fourth gear member 120 engages with an EGR valve 135 through a second shaft 145.

[0025] The gear arrangement 100 is located at the inlet manifold of the internal combustion engine. In one embodiment diameter of the third gear member 115 is greater than the diameter of the second gear member 110. However, the diameter size is not limited to the one mentioned above and the diameter of second gear member 110 can be greater than the diameter of the third gear member 115. The diameters of the second gear member 110 and the third gear member 115 are unequal to facilitate different combination of percentage openings of the EGR valve 135 and the air throttle valve 130.

[0026] The profile of the second gear member 110 is such that gear teeth are present in at least one part of the second gear member 110. The remaining part of the second gear member 110 does not include the gear teeth. Similarly, the third gear member 115 such that gear teeth are present in at least one part of the third gear member 115 and the remaining part of the third gear member 115 does not include the gear teeth. The presence of gear teeth in at least one part of the gear member and not throughout is to facilitate different combinations of percentage openings of air throttle valve 130 and the EGR valve 135.

[0027] It must be understood that the embodiments explained above are only illustrative and do not limit the scope of the disclosure. Many modifications in the embodiments with regard to the type of gear members used, the type of motor 125 used are envisaged and form a part of this invention. The scope of the invention is only limited by the claims.