Patent Application
20200398679
The present invention pertains to work vehicles and, more specifically, to work vehicles with alternators.
Work vehicles, e.g., tractors, harvesters, skid steers, etc., generally include an electrical system that powers various components of the work vehicle. The electrical system includes an alternator and a battery electrically coupled to the alternator. The alternator is mechanically coupled to output of a prime mover, such as an engine, to convert mechanical power output by the engine into electrical power that keeps the battery charged and the components powered. With work vehicles incorporating electrical components that require increasing amounts of electrical power, the demands on the electrical system have grown significantly.
What is needed in the art is a work vehicle that can provide sufficient electrical power for electrical components of the work vehicle.
Exemplary embodiments disclosed herein provide a variable transmission assembly coupled to an alternator and a controller that is configured to control at least one solenoid to adjust a gear ratio of the variable transmission assembly if a rotation speed of an alternator input is different than a set rotation speed.
In some exemplary embodiments provided in accordance with the present disclosure, an alternator assembly for a work vehicle includes: an alternator having an alternator input, the alternator being configured to convert rotational motion of the alternator input into electrical current; a variable transmission assembly including an input pulley, an output pulley coupled to the input pulley and the alternator input, and at least one solenoid configured to act on at least one of the input pulley or the output pulley to adjust a gear ratio between the input pulley and the output pulley; a rotation speed sensor coupled with at least one of the output pulley or the alternator input and configured to output a first signal corresponding to a rotation speed of the alternator input; and a controller operatively coupled to the at least one solenoid and the rotational speed sensor. The controller is configured to: receive the output first signal; determine the rotation speed of the alternator input based on the received first signal; compare the rotation speed of the alternator input to a set rotation speed; and output an adjustment signal to the at least one solenoid if the rotation speed of the alternator input differs from the set rotation speed so the at least one solenoid adjusts the gear ratio such that the rotation speed of the alternator input is equal to the set rotation speed.
In some exemplary embodiments provided in accordance with the present disclosure, a work vehicle includes: a chassis; an engine carried by the chassis and having an engine output shaft; a battery carried by the chassis; an alternator electrically coupled to the battery and having an alternator input, the alternator being configured to convert rotational motion of the alternator input into electrical current that is output to the battery; a variable transmission assembly including an input pulley coupled to the engine output shaft, an output pulley coupled to the input pulley and the alternator input, and at least one solenoid configured to act on at least one of the input pulley or the output pulley to adjust a gear ratio between the input pulley and the output pulley; a rotation speed sensor coupled with at least one of the output pulley or the alternator input and configured to output a first signal corresponding to a rotation speed of the alternator input; and a controller operatively coupled to the at least one solenoid and the rotational speed sensor. The controller is configured to: receive the output first signal; determine the rotation speed of the alternator input based on the received first signal; compare the rotation speed of the alternator input to a set rotation speed; and output an adjustment signal to the at least one solenoid if the rotation speed of the alternator input differs from the set rotation speed so the at least one solenoid adjusts the gear ratio such that the rotation speed of the alternator input is equal to the set rotation speed.
In some exemplary embodiments, a method for maintaining electrical current output of an alternator of a work vehicle is provided. The alternator includes an alternator input that is coupled to an output pulley of a variable transmission assembly, the output pulley being coupled to an input pulley. The method is performed by a controller and includes: receiving a first signal from a rotation speed sensor coupled to at least one of the output pulley or the alternator input, the first signal corresponding to a rotation speed of the alternator input; determining the rotation speed of the alternator input based on the received first signal; comparing the rotation speed of the alternator input to a set rotation speed; and outputting an adjustment signal to at least one solenoid if the rotation speed of the alternator input differs from the set rotation speed so the at least one solenoid adjusts a gear ratio between the input pulley and the output pulley such that the rotation speed of the alternator input is equal to the set rotation speed.
One possible advantage that may be realized by exemplary embodiments disclosed herein is that the alternator input may be continuously rotating at a set rotation speed so the electrical current output of the alternator is consistent.
Another possible advantage that may be realized by exemplary embodiments disclosed herein is that the set rotation speed may be a rotation speed at which the alternator outputs a maximum electrical current so the alternator output is always maximized regardless of the engine rotation speed.
For the purpose of illustration, there are shown in the drawings certain embodiments of the present disclosure. It should be understood, however, that the invention is not limited to the precise arrangements, dimensions, and instruments shown. Like numerals indicate like elements throughout the drawings. In the drawings:
Referring now to the drawings, and more particularly to
As shown in
The work vehicle 100 includes an electrical system 130 that includes a battery 132 carried by the chassis 116 and an alternator assembly 133 including an alternator 134 electrically coupled to the battery 132. As is known, various components can be electrically coupled to the battery 132 to receive electrical power needed for operation. The alternator 134 is configured to convert rotational motion of an alternator input 136 into electrical current that is output to the battery 132. As illustrated, the alternator input 136 is a shaft, but it should be appreciated that the alternator input 136 can be a different type of rotatable element, such as a chain.
To rotate the alternator input 136 and produce electrical current, a variable transmission assembly 140 is provided that links rotational motion of the engine output shaft 123 to the alternator input 136. The variable transmission assembly 140 may, for example, be directly coupled to the engine output shaft 123. The engine output shaft 123 transmits power from the engine 122 to the variable transmission assembly 140, which then transmits power to the alternator input 136 to produce electrical current.
In known alternator assemblies, the electrical output of the alternator depends on the rotation speed of the engine. As the demands on the electrical systems of work vehicles increase, it has been found that the alternator is sometimes unable to provide sufficient electrical power to operate all of the electrical components of the work vehicle. This insufficiency can be especially pronounced when the engine is idling, which represents the lowest rotation speed of the engine. Thus, some work vehicles lose functionality of one or more electronic components at idle because there is insufficient electrical power to operate all of the electronic components.
To reduce the risk of low engine speed resulting in insufficient electrical power, and referring now to
Each pulley 241, 242 may have a conical shape and include a fixed portion 246A, 247A coupled to an adjustable portion 246B, 247B, with the adjustable portions 246B, 247B coupled to the respective solenoids 243, 244. The fixed portion 246A of the input pulley 241 may be coupled to the engine output shaft 123 and the fixed portion 247A of the output pulley 242 may be coupled to the alternator input 136. The solenoids 243, 244 can act on the pulleys 241, 242 by displacing the adjustable portions 246B, 247B to adjust a gear ratio between the pulleys 241, 242, as is known. The gear ratio between the pulleys 241, 242 determines a rotation speed of the alternator input 136, and thus the electrical output of the alternator 134, relative to a rotation speed of the engine output shaft 123. It should be appreciated that, in some embodiments, only one solenoid 243, 244 is provided that adjusts the gear ratio by only acting on the input pulley 241 or the output pulley 242.
A rotation speed sensor 250 is coupled to the output pulley 242 and/or the alternator input 136 and is configured to output a first signal corresponding to a rotation speed of the alternator input 136. In some embodiments, the rotation speed sensor 250 is coupled to the alternator input 136 by a sensor gear 251 that is rotatably coupled to both the rotation speed sensor 250 and the alternator input 136. The sensor gear 251 may, for example, be rotatably mounted on the alternator input 136 so the rotation speed of the alternator input 136 is a rotation speed of the sensor gear 251, which the rotation speed sensor 250 can sense to output the first signal. Alternatively, the rotation speed sensor 250 can be coupled to the output pulley 242 and configured to sense a rotation speed of the output pulley 242, which drives rotation of the alternator input 136, and output the first signal corresponding to the rotation speed of the alternator input 136 based on the rotation speed of the output pulley 242.
The work vehicle 100 further includes a controller 160 (illustrated in
For example, if the set rotation speed of the alternator input 136 is 2600 rotations per minute (RPM) and the controller 160 determines that the rotation speed of the alternator input 136 is 1300 RPM, the controller 160 can output an adjustment signal to one of the solenoids, such as the second solenoid 244, to adjust the gear ratio between the input pulley 241 and the output pulley 242 by 2:1 so the output pulley 242, and thus the alternator input 136, rotates at double the current rotation speed, i.e., at the set rotation speed. While the previously described example is directed toward a scenario where the output alternator current is too low before adjustment of the gear ratio, the controller 160 can also be configured to adjust the gear ratio between the pulleys 241, 242 to lower the rotation speed of the alternator input 136 and avoid, for example, excessive rotation of the alternator input 136 at high rotation speeds of the engine output shaft 123. Thus, it should be appreciated that the controller 160 can adjust the gear ratio between the pulleys 241, 242 via the solenoid(s) 243, 244 so the alternator 134 can output a set amount of electrical current independently of the rotation speed of the engine 122. In some embodiments, the controller 160 is configured to only output the adjustment signal if the rotation speed of the alternator input 136 is below the set rotation speed.
The controller 160 can determine and store the gear ratio between the pulleys 241, 242 in a variety of ways. For example, the controller 160 can be operatively coupled to an input rotation speed sensor 248 that is coupled with the engine output shaft 123 and/or the input pulley 241 and configured to output a second signal corresponding to a rotation speed of the input pulley 241. The controller 160 can be configured to receive the output second signal, determine the rotation speed of the input pulley 241, and determine a current gear ratio between the input pulley 241 and the output pulley 242 based at least partially on a ratio between the rotation speed of the input pulley 241 and the rotation speed of the alternator input 136. Alternatively, the controller 160 can determine the current gear ratio based on a ratio between the rotation speed of the input pulley 241 and a rotation speed of the output pulley 242, which the controller 160 can determine directly from the rotation speed sensor 250 or indirectly based on the rotation speed of the alternator input 136. The controller 160 may then calculate a new gear ratio where the rotation speed of the alternator input 136 is equal to the set rotation speed based at least partially on the determined current gear ratio and the rotation speed of the alternator input 136 and output the adjustment signal to the solenoid(s) 243, 244 to adjust the current gear ratio between the pulleys 241, 242 to the new gear ratio so the rotation speed of the alternator input 136 is equal to the set rotation speed. Such an embodiment allows the controller 160 to signal for gear ratio adjustment by monitoring the rotation speed of the transmission input (at the input pulley 241) and the rotation speed of the transmission output (at the alternator input 136).
Alternatively, the controller 160 can be operatively coupled to an engine speed sensor 249 that is coupled to the engine output shaft 123 and configured to output a third signal corresponding to a rotation speed of the engine output shaft 123. The controller 160 can be further configured to receive the output third signal, determine the rotation speed of the engine output shaft 123 based on the received third signal, and determine a current effective gear ratio between the input pulley 241 and the output pulley 242 based at least partially on a ratio between the rotation speed of the engine output shaft 123 and the rotation speed of the alternator input 136. The controller 160 can then calculate a new gear ratio where the rotation speed of the alternator input 136 is equal to the set rotation speed based at least partially on the current effective gear ratio and the rotation speed of the alternator input 136 and output the adjustment signal to at least one of the solenoids 243, 244 to adjust the current effective gear ratio to the new gear ratio. Such an embodiment allows the controller 160 to signal for gear ratio adjustment by monitoring the rotation speed of the engine 122 (at the engine output shaft 123) and the rotation speed of the transmission output (at the alternator input 136), which can be used to correlate the effective gear ratio of the variable transmission assembly 140 from the engine 122 to the alternator 134.
Alternatively, the controller 160 can determine the gear ratio based on a position of one or both of the solenoids 243, 244. The controller 160 can then output the adjustment signal to at least one of the solenoids 243, 244 to adjust the gear ratio between the pulleys 241, 242 so the rotation speed of the alternator input 136 is equal to the set rotation speed. Such an embodiment allows the controller 160 to determine the gear ratio based on output from sensors that may be embedded in the solenoids 243, 244. It should be appreciated that the previously described ways of the controller 160 determining the adjustment of the gear ratio needed so the rotation speed of the alternator input 136 is equal to the set rotation speed are exemplary only, and there are various other ways of configuring the controller 160 so the controller 160 can signal for the solenoid(s) 243, 244 to adjust the gear ratio so the rotation speed of the alternator input 136 is equal to the set rotation speed.
From the foregoing, it should be appreciated that the alternator assembly 133 with the variable transmission assembly 140, rotation speed sensor 250, and controller 160 provided according to the present disclosure can output a consistent electrical current from the alternator 134 independently of the rotation speed of the engine 122. This consistency can avoid electrical components not having sufficient electrical power to function when, for example, the engine 122 is idling. The controller 160 can be configured, for example, to adjust the gear ratio between the pulleys 241, 242 so the electrical current output of the alternator 134 is always at a maximum to power the electrical components of the work vehicle 100. Further, this consistency can avoid excessive rotation of the alternator input 136 at high engine speeds to reduce the wear experienced by the alternator 134.
Referring now to
Another exemplary embodiment of a method 400 for maintaining electrical current output of the alternator 134 of the work vehicle 100 provided in accordance with the present disclosure is illustrated in
It is to be understood that the steps of the methods 300 and 400 are performed by the controller 160 upon loading and executing software code or instructions which are tangibly stored on a tangible computer readable medium, such as on a magnetic medium, e.g., a computer hard drive, an optical medium, e.g., an optical disc, solid-state memory, e.g., flash memory, or other storage media known in the art. Thus, any of the functionality performed by the controller 160 described herein, such as the methods 300 and 400, is implemented in software code or instructions which are tangibly stored on a tangible computer readable medium. The controller 160 loads the software code or instructions via a direct interface with the computer readable medium or via a wired and/or wireless network. Upon loading and executing such software code or instructions by the controller 160, the controller 160 may perform any of the functionality of the controller 160 described herein, including any steps of the methods 300 and 400 described herein.
These and other advantages of the present invention will be apparent to those skilled in the art from the foregoing specification. Accordingly, it is to be recognized by those skilled in the art that changes or modifications may be made to the above-described embodiments without departing from the broad inventive concepts of the invention. It is to be understood that this invention is not limited to the particular embodiments described herein, but is intended to include all changes and modifications that are within the scope and spirit of the invention.
