Automatically adjustable oil renewal system

The present disclosure relates generally to an oil renewal system and, more particularly, to an automatically adjustable oil renewal system.

Engines require oil for lubrication of moving mechanical parts. Over time, the oil degrades and must be replaced. Typical oil replacement schedules require the oil to be changed every 500-1000 hrs of engine operation. Although effective at maintaining engine life, the interruption in engine operation required for the oil change can be a nuisance and cause a loss in production and profit, especially when the engine is powering a fleet vehicle at a commercial operation.

To minimize downtime, engine manufacturers have developed automatic oil renewal systems (ORS) that maintain good oil within the engine at all times. The ORS functions by metering used oil into the fuel system of the engine for subsequent combustion. Then, based on a detected low level of oil in the engine, new oil is automatically added to the system. Because each engine operates differently, the ORS must be tuned for a particular application to make sure that enough oil is being burned, while minimizing the amount of oil that is unnecessarily burned.

Although an improvement over periodic oil changes, the tuning described above can be difficult to perform properly. To tune the ORS, the oil must be manually sampled and tested for quality. If the quality is below an expected level, the ORS is adjusted to burn more oil. In contrast, if the oil quality is above the expected level, the burning of oil is turned down. The frequency of testing and adjusting is left to the discretion of the fleet operator/owner. And, unfortunately, this tuning process if often forgotten or disregarded resulting in poor engine operation and a reduction in engine life.

One attempt to minimize oil system tuning difficulty and required operator interaction is described in U.S. Pat. No. 5,964,318 (the \'318 patent) issued to Boyle et al. on Oct. 12, 1999. Specifically, the \'318 patent describes a system that measures the quality and level of lubricant in an engine lubricant reservoir. The system includes a valve for selectively directing a portion of the lubricant from the engine through a first conduit for return to the engine or through a second conduit for removal from the engine. Within the first conduit are one or more sensors for sensing the condition of the lubricant passing through the first conduit. These sensors are monitored by a controller, which is operative to selectively cause the valve to block the flow of lubricant through the first conduit and direct a portion of the lubricant through the second conduit based on the monitored conditions of the lubricant. The controller also directs a supply of fresh lubricant to the engine in response to the lubricant in the engine lubricant reservoir dropping below a predetermined level. The lubricant flowing through the second conduit may be intermittently mixed with fuel in the engine\'s fuel tank. The controller may limit the amount of lubricant that can be added to the fuel tank so as not to exceed a predetermined lubricant/fuel ratio for the engine.

Although the system of the \'318 patent may limit tuning and operator interaction by automating some functions (i.e., by sensing a lubricant condition and removing oil from the engine based on the condition, and by automatically replenishing the system with new oil), it may be limited. That is, no oil may be removed from the engine of the \'318 patent until the oil condition has deteriorated below an unacceptable quality level, and oil removal may only be periodic. Thus, the condition of the oil within the engine of the \'318 patent may constantly vary between a good condition and an unacceptable condition. This lack of condition consistency may affect performance of the engine and make some operations, for example emissions generation, unpredictable. Further, the system of the \'318 patent may be wasteful by replenishing oil based solely on a level of oil contained within the engine at any given time.

The disclosed oil renewal system is directed to overcoming one or more of the problems set forth above.

In one aspect, the present disclosure is directed to an oil renewal system for an engine. The oil renewal system may include a removal device configured to selectively remove oil from the engine, and a condition sensor situated to generate a condition signal indicative of an oil condition. The oil renewal system may also include a controller in communication with the condition sensor and the removal device. The controller may be configured to determine a deterioration rate of the oil based on the condition signal, and adjust a removal rate of the oil from the engine based on the deterioration rate.

In another aspect, the present disclosure is directed to a method of operating an engine. The method may include removing oil from the engine, and sensing a condition of oil circulated through the engine. The method may further include determining a deterioration rate of the oil based on the sensed condition, and adjusting a rate of the oil removing based on the deterioration rate.

FIG. 1 illustrates an exemplary engine 10 having a fuel system 12 and an oil renewal system (ORS) 14. Engine 10 is depicted in FIG. 1 and described herein as a diesel-fueled, internal combustion engine. However, it is contemplated that engine 10 may embody any other type of internal combustion engine, such as, for example, a gasoline or gaseous fuel-powered engine. Engine 10 may include an engine block 16 at least partially defining a plurality of combustion chambers (not shown). It is contemplated that Engine 10 may include any number of combustion chambers and that the combustion chambers may be disposed in an “in-line” configuration, a “V” configuration, or any other conventional configuration.

An oil pan 18 may be connected to engine block 16 to form a cavity known as a crankcase 20 located below the combustion chambers. Lubricant, for example engine oil, may be provided from oil pan 18 to engine surfaces to minimize metal-on-metal contact and thereby inhibit damage to the surfaces. Oil pan 18 may serve as a sump for collecting and supplying this lubricant.