ENGINE

FIELD OF TECHNOLOGY

Embodiments disclosed herein relate generally to an engine. More particularly, the embodiments relate to methods and systems for lubricating moving parts and bearings of an engine by a starter of the engine when the engine is not running.

BACKGROUND

A fuel-powered engine, such as a diesel engine, a gasoline engine or a natural-gas powered engine, generally includes a starter to start-up the engine so that the engine can operate under its own power. During the engine start-up state, the starter, which is usually an electric motor, can rotate by drawing power from a battery. The starter is usually coupled to a crankshaft of the engine, so that the rotation of the starter can cause the crankshaft of the engine to rotate. At the same time, a fuel line may provide fuel to combustion chambers of the engine. The fuel can be compressed by a piston that is driven by the rotation of the crankshaft. In a diesel engine, the combustion of the fuel can be caused by compressing the fuel in the combustion chambers. In a gasoline engine, sparks may be used to cause the combustion of the compressed fuel in the combustion chambers. The combustion of the fuel can generate power to push the piston and consequently keep the crankshaft rotating. After the start-up, the engine usually can run under its own power from the combustion of the fuel. Therefore, if sufficient fuel is supplied to the engine, the engine generally does not need the starter to keep the engine running after start-up.

The fuel-powered engine generally includes moving parts and bearings, such as the crankshaft and bearings for the crankshaft. These moving parts and bearings are often lubricated to minimize wearing during engine operation. If the engine operates without proper lubrication to the parts and bearings, the service life of the engine may be shortened. SUMMARY

Much wear can occur at an engine start-up state. Especially when the engine has not run for a long period of time, the lubricant can seep off the surfaces of the moving parts and bearings. Further, in some engines, an oil pump is driven by the shaft of the engine to pressurize the oil pump. Therefore, during engine start-up, the oil pump may not start to deliver the lubricant to the moving parts and bearings effectively until after the shaft of the engine has rotated for a period of time to establish a pressure in the oil pump. Consequently, when the engine starts up, the moving parts and bearings of the engine may operate in an under-lubricated condition causing engine wear.

Methods and systems to lubricate an engine with a starter of the engine when the engine is stopped are described.

In one embodiment, a method is described to activate a starter of an engine to lubricate the engine when the engine is stopped. In some embodiments, the method can include activating the starter of the engine for a predetermined period of time and/or a predetermined interval when the engine is stopped. In some embodiments, the method may include restricting fuel supply to the engine during the operation of the starter when the engine is stopped.

In some embodiments, the method may include increasing a stop-time threshold when the condition of the power supply is below a power reserve threshold.

In some embodiments, an engine control system may include a controller that is configured to control a starter of the engine. When the engine is in a stopped state, the starter controller can restrict a fuel supply to the engine and turn on the starter of the engine. In some embodiments, the starter controller can turn on the starter for a predetermined period of time and/or predetermined interval when the engine is stopped.

BRIEF DESCRIPTION OF THE DRAWINGS

Referring now to the drawings in which like reference numbers represent corresponding parts throughout.

FIG. 1 is a diagrammatic view of a work machine.

FIG. 2 is a perspective view of an engine with a starter. FIG. 3 is a block diagram of components of an engine and an engine control system.

FIG. 4 is a flow chart of a process that can be performed by a starter controller of the embodiment as shown in FIG. 3.

FIG. 5 is a cutaway view of an engine.

DETAILED DESCRIPTION

A fuel-powered engine may generally include a starter to start-up the engine before the engine can run on its own power. The starter is generally coupled to a shaft of the engine, and the shaft can be coupled to a series of pistons. During the start-up state of the engine, fuel is provided to combustion chambers of the engine, and the pistons driven by the shaft of the engine can compress the fuel in the combustion chambers.

Compression of fuel can ignite the compressed fuel in the combustion chambers, and the combustion of the fuel keeps the engine moving until for example the fuel supply to the engine is cut off.

Moving parts and bearings including the shaft and pistons of the engine may require lubrication to reduce wear and tear to the moving parts and bearings. However, a lubricant can seep away from the surfaces of the moving parts and bearings when the engine is in a stopped state. Consequently, when the engine starts up from the stopped state, the moving parts and bearings may operate without proper lubrication to the surfaces. This can cause wear and tear to the moving parts and bearings. Methods and systems configured to help engine start up with proper lubrication can increase the service life of the engine.

In the following description of the illustrated embodiments, a method is described to use a starter of an engine while the engine is in a stopped state to rotate a shaft of the engine so as to lubricate the engine. The starter may be operated in a predetermined interval and/or for a predetermined period of time when the engine is in a stopped state.

References are made to the accompanying drawings that form a part hereof, and in which is shown by way of illustration of the embodiments in which the methods and systems to lubricate an engine during a stopped state may be practiced. It is to be understood that the terms used herein are for the purpose of describing the figures and embodiments and should not be regarded as limiting the scope of the present application.

Fig. 1 illustrates a working machine 100, such as a tractor. The working machine 100 may include a main engine 110 and a cab 112. A dashboard 116 may be positioned in the cab 112, and can be configured to have a human-machine interface so that an operator of the working machine 100 can communicate with and command a controller (not shown) of the main engine 110 through the dashboard 116. The main engine 110 can be a fuel-powered engine, such as a diesel engine, a gas engine or a natural gas engine.

Referring now to Fig. 2, a perspective view of one embodiment of an engine 210 is provided. The engine 210 can be a diesel engine. The engine 210 generally has a crankshaft 220 and a camshaft 230. The crankshaft 220 and the camshaft 230 are coupled to a starter 240 by a timing belt 250. The starter 240 is also coupled to a battery 245 for providing electric power to the starter 240. The engine 210 also includes an oil pump 260 that is configured to pressurize a lubricating oil so that the oil can be distributed to moving parts and bearings (such as illustrated in Fig. 5 below) of the engine 210.

In operation, the engine 210 can have a stopped state and a running state. During the stopped state, the crankshaft 220 and camshaft 230 generally do not rotate. Fuel supply from a fuel tank 270 to combustion chambers (not shown) is generally restricted. When an operator signals the engine 210 to start-up by, for example, turning an ignition key on the dashboard 116 as illustrated in Fig. 1, the starter 240 will be activated and rotate. The starter 240 can be an electric motor that can be activated and driven by the electric power from the battery 245. The rotations of the starter 240 can be transferred to the rotations of the crankshaft 220 and the camshaft 230. In the meantime, fuel from the fuel tank 270 is provided to the engine 210. The rotation of the camshaft 230 helps injection of a fuel and air mixture into the combustion chambers of the engine, and causes the fuel and air mixture to fire. The engine 210 operation can then be sustained by continuous combustion of the fuel and air mixture inside the combustion chambers, and the engine 210 enters the running state. The starter 240 may not be necessary when the engine 210 is running on its own after start-up. The engine 210 can keep running until, for example, the fuel and air mixture is restricted from the combustion chambers by cutting off the fuel supply from the fuel tank 270.

The moving parts of the engine 210 require lubrication in the running state.

When the engine 210 stops, a lubricant on a portion of the moving parts, such as a top portion of the moving parts, may migrate away. If the engine 210 starts up under such a condition, the under lubricated moving parts and bearings may endure greater wear and tear than properly lubricated moving parts and bearings.

A method to keep the moving parts and bearings properly lubricated when the engine 210 is in a stopped state may include rotating the crankshaft 220 of the engine 210 periodically during the stopped state (i.e. without starting the engine). By rotating the crankshaft 220, existing oil that may remain for example at lower portions of the moving parts and bearings can be redistributed to form a relative uniform oil lubricating layer on the surfaces of the moving parts and bearings. Rotating the crankshaft 220 may also pressurize the oil pump 260 so that the oil pump 260 may help deliver additional oil to lubricate the moving parts and bearings. Consequently, rotating the crankshaft 220 periodically during the stopped state can help keep the moving parts and bearings lubricated during the stopped state of the engine 210.

Fig. 3 illustrates a system 300 that can be configured to control a starter 340, so that the starter 340 can help lubricate the moving parts and bearings of an engine 310 during a stopped state of the engine 310. The system 300 may include a main controller

350 and a starter controller 351. The system may have an engine control unit (ECU) 352.

The system may also include a solenoid 353 that is configured to control a fuel supply to the engine 310. It is to be noted that some fuel-powered engines 310 do not have the

ECU 352. The starter controller 351 and/or the ECU 352 can be configured to control the solenoid 353. The starter controller 351 can be configured to control a power supply 345 that can supply a power to the starter 340.

The main controller 350 may be hosted in the dashboard 116 as shown in Fig. 1.

An operator may input commands to the main controller 350. The main controller 350 is configured to be coupled to the starter controller 351 and/or the ECU 352. It is noted that in some embodiments, the starter controller 351 may be integrated in the main controller

350 and/or the ECU 352. In one embodiment as shown in Fig. 3, the ECU 352 is configured to control the operation of the engine 310. The ECU 352 can be configured to control the fuel solenoid 353 and the fuel delivery to the engine 310 when the engine is in operation. The ECU 352 can also control fuel supply during start-up of the engine 310. During the start-up, the ECU 352 can open up the solenoid 353 so that a sufficient amount of fuel can be delivered to the engine 310 during the start-up. The ECU 352 can also restrict the fuel supply to the engine 310 so that the engine 310 can stop from a running state.

The starter controller 351 is configured to control the operation of the starter 340. The starter controller 351 can determine whether to activate the starter 340 by for example supplying the power from the power supply 345 to the starter 340. If power is supplied to the starter 340 from the power supply 345, the starter 340 can be activated and driven by the power. The starter controller 351 can also be configured to deactivate the starter by restricting power to the starter 340. If the power is restricted from the starter 340, the starter 340 does not rotate on its own. The power supply may be a battery, an external source such as a plug-in power source, or any other suitable power supply.

In some embodiments, such as in embodiments without an ECU, the starter controller 351 may also be configured to directly control the solenoid 353.

In some embodiments, the starter controller 351 can control the solenoid 353 indirectly by sending solenoid controlling commands to the ECU 352, which can control the solenoid 353. The starter controller 351 may be also configured to receive

information from ECU 352. For example, the starter controller 351 can receive information from the ECU 352 regarding whether the engine 310 is currently in the running state or the stopped state. In some embodiments, the starter controller 351 may also receive information regarding the amount of residual power left in the power supply 345.

The starter controller 351 may be configured to have a microprocessor that can execute a process to determine the operation of the starter 340.

Fig. 4 illustrates one embodiment of a process 400 that can be executed, for example, by the starter controller 351. At 401 , the starter controller 351 is in a stand-by mode. At the stand-by mode 401, the starter controller 351 can receive information from the ECU 352 regarding the operation condition of the engine 310. At 402, the process determines whether the engine 310 has stopped. If the answer to the question is "no" at 402, which means that the engine 310 is still in a running state, the process goes back to stand-by mode at 401. If the answer to the question is "yes" at 402, which means that the engine has stopped, the process goes to 403.

At 403, an internal timer of the starter controller 351 starts to count the duration of the stop-time of the engine 310. The duration of the stop-time of the engine 310 can be compared to a stop-time threshold at 404. The stop-time threshold can be a period of time. In one embodiment, the stop-time threshold is about 15 minutes. In other embodiments, the stop-time threshold can be more or less than 15 minutes. In some embodiments, the stop-time threshold can be in a range of 2 minutes to 60 minutes. This stop-time threshold range may also be generated by long term endurance testing to measure the degree of engine deterioration relative to a stop-time threshold. Generally, the stop-time threshold is a time that it may take for oil on the surfaces of the moving parts and bearings to seep off from at least a portion of the moving parts and bearings after the engine 310 stops. This time can be generally determined by testing. If the answer at 404 is "no," which indicates that the engine 310 has not stopped for a period that is longer than the stop-time threshold, the process goes back to 403 and continues to count the engine stop-time. If the answer at 404 is "yes," which indicates that the engine 310 has stopped for a period that is at least the same as the stop-time threshold, the process goes to 405.

At 405, the starter controller 351 commands the solenoid 353 to restrict fuel supply to the engine 310 as shown in Fig. 3. Or the starter controller 351 can send the command to close down the solenoid 353 through the ECU 352, and the ECU 352 can close down the solenoid 353 to restrict fuel supply to the engine 310. When the fuel supply to the engine 310 is restricted, the starter controller 351 commands the starter 340 to operate at 406. The starter controller 351 can provide power from the power supply 345 to the starter 340 as shown in Fig. 3. When the power, such as a battery power, is provided to the starter 340, the starter 340 can rotate. The rotation of the starter 340 can cause the crankshaft and/or camshaft of the engine 310 to rotate so that the moving parts and bearings of the engine 310 can be lubricated. Because the fuel supply is restricted to the engine, the rotation of the starter 340 does not cause the engine to start up. The starter 340 can be operated for a period of time then stopped. In one embodiment, the operating period for the starter 340 is about 10 seconds. In other embodiments, the operating period of the starter 340 can be more or less than 10 seconds. In some embodiments, the operation period of the starter 340 can be 5 or 15 seconds. The general principle for the operating period of the starter 340 is a period of time that a substantial portion of the moving parts and bearings of the engine 310 can be lubricated. Or the operating period can be where a substantial part of the portions of the moving parts and bearings of the engine 410 that lose lubrication during the engine stopped state can be re- lubricated. The period of time at 406 can be determined, for example, by testing. For example, in one embodiment, the period of time at 406 can be determined by measuring oil pressure in an oil pump. Once a satisfactory level of pressure in the oil pump is established, the starter can be disengaged or stopped.

The process 400 can also be configured to incorporate a check step 407 to determine whether a command of starting up the engine 310 is received, for example, from the main controller 350. If the answer is "yes," which means the main controller

350 sends a command to start-up the engine 310, the process 400 goes to the engine startup procedure at 408. At 408, the starter controller 351 can send command to the ECU 352 and/or the solenoid 353 to open up the fuel supply to the engine 310. If the answer is "no," which indicates that an engine start-up command is not received, the process goes back to 403. The timer is reset to 0, and a new count of engine stop-time starts at 403.

After the engine 310 starts up at 408, the process 400 of the start controller 351 goes back to 401, and the start controller 351 goes back to the stand-by mode and waits for the engine to stop.

It is to be noted that the starter controller 351 can be configured so that the process 400 can be interrupted at any point by the commands from the main controller

350. For example, even where the stop-time threshold has not been reached at 404, if the main controller 350 sends a command to the starter controller 351 to start up the engine 310, the process 400 can be interrupted, and the process 400 can jump from 404 to 408 so as to start the engine 310.

It is also to be appreciated that the stop-time threshold and the operating period of the starter 340 at 406 can be varied. For example, to prevent the power supply 345 as shown in Fig. 3 from running out of power, the starter controller 351 can be configured to check the current power supply condition, such as an amount of residual power in the power supply 345. The starter controller 351 can be configured to compare the current power supply condition to a minimal power reserve threshold. The minimal power reserve threshold may be the power required to start the engine 310. If the starter controller 351 detects that the current power supply condition is equal to or less than the minimal power reserve threshold, the starter controller 351 can be configured to suspend the process 400 and deactivated the starter 340. In some embodiments, the process 400 can be configured so that the stop-time threshold becomes longer when the current battery condition of the power supply 345 gets closer to the minimal battery reserve threshold. Further, the operation time at 406 may be shortened as the current power supply condition of the power supply 345 gets close to the minimal battery reserve threshold. By extending the stop-time threshold, shortening the time period to operate the starter, and/or suspend the process 400 and deactivated the starter 340, the power supply 345 can be prevented from running out of power supply when the engine 310 stops.

It is to be appreciated that the power supply 345 as shown in Fig. 3 may be a main battery of the engine 310 as shown in Fig. 3, or may be an auxiliary battery of the engine 310. When the engine 310 stops, the process 400 can draw power from the main battery of the engine 310 to operate the starter 340, or the process 400 can be restricted from drawing power from the main battery of the engine 310 and only permitted to draw power from the auxiliary battery so as to prevent the main battery of the engine 210 from running out of power. In other embodiments, the power supply 345 can be a plug-in power source or any other suitable power sources

Referring now to Fig. 5, an embodiment of the operation of an oil pump 560 of an engine 510 and lubrication of moving parts of the engine 510 is illustrated. An internal space 562 (i.e. oil sump) may be supplied with a lubricant, such as oil. The arrows in Fig. 5 generally indicate the distribution of the oil. The oil flows to the oil pump 560, which is coupled to a crankshaft 520 of the engine 510, for example by gears 565. The rotation of the crankshaft 520 can cause the oil to be pressurized inside the oil pump 560 and is distributed to other parts of the engine 510 as shown by the arrows. The oil can be distributed to moving parts and bearings of the engine 510. For example, the oil can be distributed to a front bearings 572a, a rear bearings 572b and internal bearings 572c for the crankshaft 520, and bearings 573 of the camshaft 530. The oil can also be distributed to the gears 565 and a piston 580 that moves reciprocally inside a combustion chamber 581. The oil can help prevent the moving parts and bearings from wear and tear during the operation of the engine 510.

It is to be noted that at least some of the moving parts and bearings of the engine 510 are driven by the crankshaft 520 and/or the camshaft 530. When the engine 510 stops, the crankshaft 520 and the camshaft 530 stop. The moving parts and bearings of the engine 510 consequently stop moving. The oil pressure generated by the oil pump 560 also decreases, because the operation of the oil pump 560 is also driven by the crankshaft 520. Without the oil pressure, the oil is not distributed to the moving parts and bearings as shown by the arrows. The oil on the surface of the moving parts and bearings can seep away for example from upper portions of the moving parts and bearings for example due to gravity. Consequently, a portion of the moving parts and bearings may become under lubricated by the oil. If the engine 510 starts up under such a condition, the under lubricated moving parts and bearings may endure greater wear and tear than properly lubricated moving parts and bearings.

If the crankshaft 520 and/or camshaft 530 of the engine 510 are periodically rotated when the engine 510 is stopped as disclosed herein, the oil may be redistributed so that the moving parts and bearings can be properly lubricated when the engine 510 is stopped. The rotation of the crankshaft 520 and/or camshaft 530 may also help increase the oil pressure in the oil pump 560. The pressure of the oil in the oil pump 560 can also help distribute oil to the moving parts and bearings. It is to be appreciated that the embodiments described here are not limited to engines described herein. The

embodiments can generally be used in any engine that has a starter and requires lubrication of moving parts/components subject to frictional wear.

Aspects:

It is noted that any of aspects 1-6 can be combined with any of aspects 7-9. Aspect 1. A method of using a starter of an engine to lubricate the engine when the engine is in a stopped state comprising:

determining an engine operation state;

determining an engine stop-time when the engine operation state is in the stopped state;

when the engine stop-time reaches a stop-time threshold, restricting a fuel supply to the engine and activating a starter of the engine by providing power from a power supply to the starter; and

lubricating the engine by activating the starter while the engine is in the stopped state.

Aspect 2. The method of aspect 1 further comprising activating the starter of the engine for a predetermined period of time.

Aspect 3. The method of aspects 1-2 further comprising activating the starter of the engine in a predetermined interval.

Aspect 4. The method of aspects 1-3 further comprising determining a condition of the power supply.

Aspect 5. The method of aspect 4 further comprising:

increasing the stop-time threshold when the condition of the power supply is equal to or below a power reserve threshold.

Aspect 6. The method of aspects 4-5 further comprising:

deactivating the starter of the engine if the power supply is equal to or below a power reserve threshold

Aspect 7. An engine system comprising:

an engine;

a starter of the engine;

a controller that is configured to control the starter of the engine, the starter is coupled to a shaft of the engine; wherein when the engine is in a stopped state the controller is configured to restrict fuel to the engine and is configured to activate the starter of the engine to rotate the shaft to lubricate the engine.

Aspect 8. The engine system of claim 7, wherein the controller is configured to activate the starter of the engine in a predetermined interval. Aspect 9. The engine system of claim 7-8, wherein the controller is configured to activate the starter of the engine for a predetermined period of time.

With regard to the foregoing description, it is to be understood that changes may be made in detail, especially in matters of the construction materials employed and the shape, size and arrangement of the parts without departing from the scope of the present invention. It is intended that the specification and depicted embodiment to be considered exemplary only, with a true scope and spirit of the invention being indicated by the broad meaning of the claims.