Claims:WE CLAIM:

1. A system (100) for controlling RPM of an engine during a power take-off (PTO) operation, the system comprising:
a selection lever (110) movable in one or more positions to select a particular PTO mode, each PTO mode corresponds to a pre-set RPM required for the PTO operation;
an accelerator lever (120) movable in one or more positions, each position of the accelerator lever (120) operates the engine at the pre-set RPM corresponding to selected PTO mode;
a first sensor (130) for detecting position of the selection lever (110); and
a second sensor (140) for detecting position of the accelerator lever (120); and
a control unit (150) configured to:
receive position information from the first sensor (130) to identify the PTO mode and the corresponding pre-set RPM;
receive position information from the second sensor (140) to monitor position of the accelerator lever (120), and verify if the accelerator level (120) is at the position required to operate the engine at pre-set RPM; and

lock position of the accelerator lever (120) if the accelerator lever (120) has reached the required position to operate the engine at the pre-set RPM.

2. The system (100) as claimed in claim 1, wherein the selection lever (110) is manually operated.

3. The system (100) as claimed in claim 1, wherein accelerator lever (120) is automatically operated or manually operated.

4. The system (100) as claimed in claim 3, wherein accelerator lever (120) is automatically operated by a stepper motor (160).

5. The system (100) as claimed in claim 1, wherein a locking mechanism is provided to lock the position of accelerator lever (120) for maintaining position of the accelerator lever (120) to operate the engine at the pre-set RPM.

6. The system (100) as claimed in claim 1, wherein the locking mechanism is an electromagnetic locking mechanism or solenoid based locking mechanism.

7. The system (100) as claimed in claim 1, wherein the first sensor (130) and the second sensor (140) is a position sensor.

8. A method for controlling RPM of an engine during a power take-off (PTO) operation, the method comprising the steps of:
selecting a PTO mode by moving a selection lever (110) in one or more positions, each PTO mode corresponds to a pre-set RPM required for the PTO operation;
detecting position of the selection lever (110) via a first sensor (130);
receiving at a control unit (150) position information from the first sensor to identify the PTO mode and corresponding pre-set RPM;
operating an accelerator lever (120) in one or more positions, each position of the accelerator lever (120) operates the engine at the pre-set RPM corresponding to selected PTO mode;
monitoring position of the accelerator lever (120) via a second sensor (140); to verify if the accelerator lever (120) is at the position required to operate the engine at the pre-set RPM; and
locking position of the accelerator lever (120) if the accelerator lever (120) has reached the required position to operate the engine at the pre-set RPM.

9. The method as claimed in claim 8, wherein the PTO mode is selected by manually operating the selection lever (110).

10. The method as claimed in claim 8, wherein the accelerator lever (120) is automatically operated or manually operated.
11. The method as claimed in claim 10, wherein the accelerator lever (120) is automatically operated by a stepper motor (160).

12. The method as claimed in claim 8, wherein a locking mechanism is provided to lock the position of accelerator lever (120) for maintaining position of the accelerator lever (120) to operate the engine at the pre-set RPM.

13. The method as claimed in claim 12, wherein the locking mechanism is an electromagnetic locking mechanism or solenoid based locking mechanism.

14. The method as claimed in claim 8, wherein the first sensor (130) and the second sensor (140) is a position sensor.

Dated this 31 day of December 2018

MAHINDRA & MAHINDRA LIMITED
By their Agent & Attorney

(Janaksinh Jhala)
of Khaitan & Co
Reg. No. IN/PA-2193
, Description:FORM 2

THE PATENTS ACT, 1970
As amended by the Patents (Amendment) Act, 2002
and
The Patents Rules, 2003
As amended by the Patents (Amendment) Rules 2016

COMPLETE SPECIFICATION
(Section 10 and Rule 13)

TITLE OF THE INVENTION
A system and method for controlling RPM of an engine

APPLICANTS
MAHINDRA & MAHINDRA LIMITED, an Indian company of Mahindra Research Valley, Mahindra World City, Plot No:41/1, Anjur P.O., Chengalpattu 603004, Tamilnadu, India

PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the invention and the manner in which it is to be performed

FIELD OF THE INVENTION
[001] The invention relates to controlling RPM of an engine, more particularly to a system and method for controlling RPM of an engine during a power take-off (PTO) operation.

BACKGROUND OF THE INVENTION
[002] Generally, work vehicles or agricultural vehicles, for example tractors, earth movers, etc., have working/auxiliary implements. A power take-off or PTO unit is provided on such vehicles for transferring power from the engine to the auxiliary implements.
[003] The PTO unit typically comprises of an actuation lever, and a shaft which engages with the auxiliary implements. In order to engage the PTO, the actuation lever is engaged and according to position of the actuation lever the engine is required to be accelerated manually by the operator to the required engine revolution per minute (RPM) via an accelerator lever. Manually operating the accelerator lever to achieve the required RPM requires skill. Thus, the chances of the engine being accelerated erroneously/wrongly are high.
[004] Considering, most of the auxiliary implements have different output requirements such as speed, torque, etc it is critical to operate the engine at the correct RPM. In case the engine is operated at a different engine RPM than the predefined/required RPM, then the required speed will not be achieved at the PTO. Also, higher RPM than required RPM results in higher fuel consumption of the engine or may even damage the implement, and lower RPM than required RPM effects the operability of the implement. Thus, it is important to achieve the right engine RPM to yield optimum result and for safety of PTO and attached implement. The present method/technique of setting of engine RPM being manual is prone to human errors.
[005] In view of the above, there is a need to address at-least the aforementioned shortcomings and provide a system which can provide better controlling of engine RPM corresponding to the output requirements at PTO.

SUMMARY OF THE INVENTION
[006] Accordingly, the present invention in one aspect provides a system for controlling RPM of an engine during a power take-off (PTO) operation, the system comprising: a selection lever movable in one or more positions to select a particular PTO mode, each PTO mode corresponds to a pre-set RPM required for the PTO operation; an accelerator lever movable in one or more positions, each position of the accelerator lever operates the engine at the pre-set RPM corresponding to selected PTO mode; a first sensor for detecting position of the selection lever; and a second sensor for detecting position of the accelerator lever; and a control unit configured to receive position information from the first sensor to identify the PTO mode and the corresponding pre-set RPM; receive position information from the second sensor to monitor position of the accelerator lever, and verify if the accelerator level is at the position required to operate the engine at pre-set RPM; and lock position of the accelerator lever if the accelerator lever has reached the required position to operate the engine at the pre-set RPM.
[007] In another aspect, the present invention provides a method for controlling RPM of an engine during a power take-off (PTO) operation, the method comprising the steps of selecting a PTO mode by moving a selection lever movable in one or more positions, each PTO mode corresponds to a pre-set RPM required for the PTO operation; detecting position of the selection lever via a first sensor; receiving at a control unit position information to identify the PTO mode and corresponding pre-set RPM; operating an accelerator lever in one or more positions, each position of the accelerator lever operates the engine at the pre-set RPM corresponding to selected PTO mode; monitoring position of the accelerator lever via a second sensor; to verify if the accelerator lever is at the position required to operate the engine at the pre-set RPM; and locking position of the accelerator lever if the accelerator lever has reached the required position to operate the engine at the pre-set RPM.

BRIEF DESCRIPTION OF THE DRAWINGS
[008] Reference will be made to embodiments of the invention, examples of which may be illustrated in accompanying figures. These figures are intended to be illustrative, not limiting. Although the invention is generally described in context of these embodiments, it should be understood that it is not intended to limit the scope of the invention to these particular embodiments.
Figure 1 shows a system for controlling RPM of an engine in accordance with an embodiment of the invention.
Figure 2 shows a method for controlling RPM of an engine in accordance with an embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[009] The present invention is directed towards controlling RPM of an engine during a power take-off (PTO) operation such that the RPM of the engine corresponds with the output requirements at PTO.
[010] Figure 1 shows a system 100 for controlling RPM of an engine during a PTO operation in accordance with an embodiment of the invention. As discussed hereinabove, a work vehicle has plurality of auxiliary implements and each such auxiliary implement has a specific RPM requirement. The system 100 of the present invention ensures that engine is operated at the correct RPM to drive each auxiliary implement.
[011] The system 100 comprises of a selection lever 110, an accelerator lever 120, a first sensor 130, a second sensor 140, and a control unit 150.
[012] The selection lever 110 is provided for selecting a PTO mode for operating the auxiliary implements. The selection lever 110 is movable in one or more positions, and each position of the selection lever 110 corresponds to a particular PTO mode. In an embodiment, each PTO mode corresponds with a pre-set RPM required for operating the auxiliary implement. Accordingly, upon selecting a particular PTO mode, the RPM of the engine will be as per the requirement of the auxiliary implement. The selection lever 110 is provided inside a vehicle cabin and is operable manually by an operator to select the PTO mode. Further, the first sensor 130 is provided at the base of the selection lever 110 for detecting position of the selection lever 110. The first sensor 130 is a position sensor which can be selected from any of a hall effect sensor, magneto restrictive sensor, proximity sensor, laser doppler vibrometer, and the like.
[013] The accelerator lever 120 is provided to operate the engine at a particular pre-set RPM in response to the selected PTO mode. The accelerator lever 120 is configured to move in one or more positions depending upon the position of the selection lever 110, whereby each position of the accelerator lever 120 operates the engine at the required pre-set RPM. Accordingly, the accelerator lever 120 will operate the engine at the required pre-set RPM depending upon the PTO mode selected via the selection lever 110. The accelerator lever 120 is provided inside a vehicle cabin and is operable manually by an operator or automatically. Further, the second sensor 140 is adapted to the accelerator lever 120 for detecting position of the accelerator lever 120. The second sensor 140 is a position sensor which can be selected from any of a hall effect sensor, magneto restrictive sensor, proximity sensor, laser doppler vibrometer, and the like.
[014] The first sensor 130 and the second sensor 140 are electrically connected with the control unit 150. The control unit 150 in an embodiment of the invention is an electronic control unit of the vehicle, which is already on board the vehicle. Alternately, control unit 150 can be a dedicated unit installed specifically for the system 100 of the present invention. The control unit 150 is configured to be responsive to the first sensor 130 and second sensor 140, and process position information of the selection lever 110 and the accelerator lever 120. Upon receiving position information from the first sensor 130, the control unit 150 identifies the PTO mode and the corresponding pre-set RPM. Further, the control unit 150 receives position information from the second sensor 140 to monitor position of the accelerator lever 120, and verify if the accelerator lever 120 is at the position required to operate the engine at pre-set RPM. Thereafter, the accelerator lever 120 is locked ensuring that the engine is operated at RPM required by the auxiliary implement.
[015] In an embodiment, the system 100 of the present invention can be configured to operate in an automatic mode. In the automatic mode, the accelerator lever 120 is moved and locked at a particular position via a stepper motor 160 so as to operate the engine at pre-set RPM. The stepper motor 160 is connected with the accelerator lever 120 via shaft 190 to move the accelerator lever 120. The stepper motor 160 causes the accelerator lever 120 to move such that the accelerator lever 120 operates the engine at the required/pre-set RPM. The stepper motor 160 moves the accelerator lever 120 by a preset angle with the help of attached shaft 190, and each such angel corresponds to the RPM/requirement of the selected PTO mode. Accordingly, the engine will be accelerated as per the required RPM. Further, the stepper motor 160 locks the accelerator lever 120 in its position ensuring stabilization of the accelerator lever 120 during field operations.
[016] In an embodiment, the system 100 of the present invention can be configured to operate in a semi-automatic mode. In the semi-automatic mode, the accelerator lever 120 is moved manually, and thereafter locked at a particular position via a locking mechanism so as to operate the engine at pre-set RPM. The locking mechanism prevents human error in setting correct engine RPM. The locking mechanism is configured to actuate as soon as the accelerator lever 120 reaches the required position corresponding to the RPM requirement. In this regard, as discussed hereinbefore the position of the accelerator lever 120 is monitored by the second sensor 140.
[017] In an embodiment, the locking mechanism is an electromagnetic locking mechanism. The electromagnetic locking mechanism is adapted to the accelerator lever 120. As is known in the art, an accelerator lever typically comprises of a shaft mounted on a pivot pin. The electromagnetic locking mechanism is configured to lock the pivot pin of the accelerator lever 120. The electromagnetic locking mechanism comprises an electromagnet and an armature. The electromagnet is provided around the pivot pin, and the armature is provided on the pivot pin for electromagnetic engagement with the electromagnet. Accordingly, when the electromagnet is energized, the armature, and thereby the pivot pin of the accelerator shaft is attracted to the electromagnet which locks the movement of the accelerator shaft. The electromagnet is energized by the control unit 150 once it is determined that position of the accelerator lever 120 is in required position. In another embodiment, the locking mechanism is a solenoid locking mechanism. The solenoid locking mechanism is adapted to the accelerator lever 120. As mentioned hereinbefore, an accelerator lever typically comprises of a shaft mounted on a pivot pin. The solenoid locking mechanism is configured to lock the pivot pin of the accelerator lever 120. The solenoid locking mechanism comprises a circular disc and a solenoid actuator. The circular disc is provided on the pivot pin, and has plurality of slots. The solenoid actuator has a plunger engageable with the slots of the circular disc. Accordingly, when the solenoid actuator is actuated, the plunger engages with the slot and blocks movement of the circular disc, and thereby the pivot pin of the accelerator shaft which locks the movement of the accelerator shaft. The solenoid actuator is actuated by the control unit 150 once it is determined that position of the accelerator lever 120 is in required position.
[018] The system 100 further comprises of a torque sensor 170 for detecting rotation of the accelerator lever 120. In this regard, the torque sensor 170 sends the position information of the accelerator lever 120 being rotated to the control unit 150, and the control unit 150 actuates the stepper motor 160 to assist in movement/rotation of accelerator lever 120. The effort, thus required to operate the accelerator lever 120 is reduced.
[019] The system 100 further comprises a load switch 180 connected with the control unit 150. The control unit 150 through the load switch 180 ensures that there is load connected through the load switch 180, which acts as a safety feature to prevent any accident.
[020] Figure 2 shows a method for controlling RPM of an engine during a power take-off (PTO) operation in accordance with an embodiment of the invention. In order to implement such a method, the invention is used or integrated with the system discussed hereinbefore.
[021] The method begins at step 2A, where a PTO mode is selected by moving a selection lever 110 in a desired position. In this regard, the selection lever 110 is movable in one or more positions to select the PTO mode, whereby each PTO mode corresponds to a pre-set RPM required for the PTO operation. The method at step 2B detects the position of the selection lever 110 via a first sensor 130 to identify the selected PTO mode. Based on the position of the selection lever 110, the method at step 2C, determined the pre-set RPM corresponding with the PTO mode. The method at step 2D operates an accelerator lever 120. The accelerator lever 120 is movable in one or more positions, and each position of the accelerator lever 120 operates the engine at the pre-set RPM corresponding to selected PTO mode. The method at step 2E monitors position of the accelerator lever 120 via a second sensor 140 to verify if the accelerator lever 120 is at the position required to operate the engine at the pre-set RPM. . Further, the method at step 2F locks the accelerator lever 120 to prevent human error in setting correct engine RPM. The accelerator lever 120 is locked as soon as the accelerator lever 120 reaches the required position corresponding to the RPM requirement.
[022] The method of the present invention can be configured to operate in an automatic mode or a semi-automatic mode. In the automatic mode, the accelerator lever 120 is moved and locked at a particular position via the stepper motor 160 so as to operate the engine at pre-set RPM. Accordingly, at step 2D, the stepper motor 160 is operated to move the accelerator shaft, and upon reaching the required position, the stepper motor 160 locks the accelerator lever 120 in its position ensuring stabilization of the accelerator lever 120 during field operations.
[023] In the semi-automatic mode, as discussed hereinbefore the accelerator lever 120 is moved manually, and thereafter locked at a particular position via a locking mechanism so as to operate the engine at pre-set RPM. Accordingly, at step 2D, the accelerator shaft is operated manually, and upon reaching the required position, the locking mechanism at step 2F locks the accelerator lever 120 in its position ensuring stabilization of the accelerator lever 120 during field operations.
[024] Advantageously, the present invention ensures that the engine is operated as per the output requirement at PTO, thereby ensuring better fuel efficiency. Also, the present invention reduces time and effort required to operate the engine at required RPM.
[025] While the present invention has been described with respect to certain embodiments, it will be apparent to those skilled in the art that various changes and modification may be made without departing from the scope of the invention as defined in the following claims.