Patent Application
20100018805
This disclosure is related to controlling lubrication of an internal combustion engine.
The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
An internal combustion engine is a complex mechanism involving a great number of mechanical, moving parts subject to high speeds, high temperatures, forces of large magnitude, fatigue, friction, contamination, and corrosion. Lubrication through the circulation and application of oil within the engine is well known in the art as a means to reduce wear by friction, reduce heat, and remove contaminants from particular surfaces. Under normal engine operation, internal combustion engines of various configurations and fuel types utilize an oil pump to circulate and distribute oil from an oil collection area or an oil pan through an oil channeling system to critical areas, such as engine bearings, cylinders, and head valve mechanisms. However, the oil pump does not operate when the engine is turned off.
Gravity acts upon oil in an engine. Oil which was distributed during the last operating cycle is slowly pulled by gravity through the engine into the oil pan, leaving engine surfaces exposed and insufficiently lubricated. While engine start-up activates the oil pump, and oil begins to circulate through the engine again, engine start-up involves a period of time in which the components of the engine operate with little or no oil present. Under ideal conditions, this oil-starved period is short, and the engine operates at idle conditions, reducing the wear on the engine. However, under non-ideal conditions, significant damage to the engine can result. One example of non-ideal conditions includes cold environmental conditions. Oil increases internal frictional forces or viscosity in cold temperatures and becomes thickened. Oil containing contaminants can also become thickened. Thickened oil takes longer for the oil pump to move through the oil channeling system, increasing the period in which damage is done to the engine. Another example of non-ideal conditions includes start-ups followed by immediate operator demand for engine output. If an operator starts and engine and immediately applies pedal input to move the vehicle, the increased forces applied within the engine as a result of the pedal input in the absence of proper lubrication can drastically increase wear upon engine components. Another example of non-ideal conditions includes dealer staging operations, in which unsold vehicles are moved around a dealer's lot with great frequency, sometimes involving a multitude of brief engine starts wherein the vehicle only moved slightly, but each start-up can include operation without proper lubrication. Any of these non-ideal conditions can increase wear upon the engine components and cause maintenance issues.
Methods are known to pre-lubricate an engine by injecting oil onto critical engine parts before operation. Methods are known whereby an electric oil pump, frequently an auxiliary oil pump to the main oil pump, is activated to distribute oil prior to engine start-up. One method to initiate pre-lubrication is to activate the electric oil pump on a timer or upon a control signal of some programmed frequency. This method is effective to pre-lubricate the engine, however the periodic activation of the electric oil pump can create a significant drain upon the battery of the vehicle, creating or exacerbating parasitic drain issues. Additionally, the actual protection created by timed pre-lubrication can be dependent upon how recently the last injection occurred before the start-up event. Another method to initiate pre-lubrication is to accept a keyed ignition request from an operator but delay actual engine start-up briefly while the electric oil pump is activated. This method is effective in pre-lubricating the engine, but the delay imposed upon the operator may be a source of dissatisfaction with the operator. Another method to initiate pre-lubrication includes activating the electric oil pump upon a signal from a keyless entry system, typically by a key fob radio frequency device. This method can be effective but is dependent upon the time elapsed between the keyless entry command and the engine ignition, and additionally is ineffective where the operator has not locked the vehicle, such as in a garage.
A method for initiating oil injection into a cylinder of an internal combustion engine prior to engine start-up to protect the engine from damage caused by insufficient lubrication during the start-up includes processing data to modulate a lubrication initiation modifier and initiating the oil injection on the basis of the lubrication initiation modifier.
One or more embodiments will now be described, by way of example, with reference to the accompanying drawings, in which:
Referring now to the drawings, wherein the showings are for the purpose of illustrating certain exemplary embodiments only and not for the purpose of limiting the same,
Sensing devices are installed on or near the engine to monitor physical characteristics and generate signals which are correlatable to engine and ambient parameters. The sensing devices include a crankshaft rotation sensor, comprising a crank sensor 44 for monitoring crankshaft speed (RPM) through sensing edges on the teeth of the multi-tooth target wheel 26. The crank sensor is known, and may comprise, e.g., a Hall-effect sensor, an inductive sensor, or a magnetoresistive sensor. Signal output from the crank sensor 44 (RPM) is input to the control module 5. There is a combustion pressure sensor 30, comprising a pressure sensing device adapted to monitor in-cylinder pressure (COMB_PR). The combustion pressure sensor 30 preferably comprises a non-intrusive device comprising a force transducer having an annular cross-section that is adapted to be installed into the cylinder head at an opening for a glow-plug 28. The combustion pressure sensor 30 is installed in conjunction with the glow-plug 28, with combustion pressure mechanically transmitted through the glow-plug to the sensor 30. The output signal of the sensing element of sensor 30 is proportional to cylinder pressure. The sensing element of sensor 30 comprises a piezoceramic or other device adaptable as such. Other sensing devices preferably include a manifold pressure sensor for monitoring manifold pressure (MAP) and ambient barometric pressure (BARO), a mass air flow sensor for monitoring intake mass air flow (MAF) and intake air temperature (TIN), and, a coolant sensor 35 (COOLANT). The system may include an exhaust gas sensor (not shown) for monitoring states of one or more exhaust gas parameters, e.g., temperature, air/fuel ratio, and constituents. One having ordinary skill in the art understands that there may other sensing devices and methods for purposes of control and diagnostics. The engine is preferably equipped with other sensors (not shown) for monitoring operation and for purposes of system control. Each of the sensing devices is signally connected to the control module 5 to provide signal information which is transformed by the control module to information representative of the respective monitored parameter. It is understood that this configuration is illustrative, not restrictive, including the various sensing devices being replaceable with functionally equivalent devices.
The actuators are installed on the engine and controlled by the control module 5 in response to operator inputs to achieve various performance goals. Actuators include an electronically-controlled throttle device which controls throttle opening to a commanded input (ETC), and a plurality of fuel injectors 12 for directly injecting fuel into each of the combustion chambers in response to a commanded input controlled in response to the operator torque request. There is an exhaust gas recirculation valve 32 and cooler (not shown), which controls flow of externally recirculated exhaust gas to the engine intake, in response to a control signal (EGR) from the control module. The glow-plug 28 comprises a known device, installed in each of the combustion chambers, adapted for use with the combustion pressure sensor 30.
The fuel injector 12 is an element of a fuel injection system, which comprises a plurality of high-pressure fuel injector devices each adapted to directly inject a fuel charge, comprising a mass of fuel, into one of the combustion chambers in response to the command signal from the control module. All of the fuel injectors 12 are supplied pressurized fuel from a fuel distribution system (not shown), and have operating characteristics including a minimum pulsewidth and an associated minimum controllable fuel flow rate, and a maximum fuel flowrate.
The control module 5 is preferably a general-purpose digital computer generally comprising a microprocessor or central processing unit, storage mediums comprising non-volatile memory including read only memory (ROM) and electrically programmable read only memory (EPROM), random access memory (RAM), a high speed clock, analog to digital (A/D) and digital to analog (D/A) circuitry, and input/output circuitry and devices (I/O) and appropriate signal conditioning and buffer circuitry. The control module has a set of control algorithms, comprising resident program instructions and calibrations stored in the non-volatile memory and executed to provide the respective functions of each computer. The algorithms are typically executed during preset loop cycles such that each algorithm is executed at least once each loop cycle. Algorithms are executed by the central processing unit and are operable to monitor inputs from the aforementioned sensing devices and execute control and diagnostic routines to control operation of the actuators, using preset calibrations. Loop cycles are typically executed at regular intervals, for example each 3.125, 6.25, 12.5, 25 and 100 milliseconds during ongoing engine and vehicle operation. Alternatively, algorithms may be executed in response to occurrence of an event.
The control module 5 executes algorithmic code stored therein to control the aforementioned actuators to control engine operation, including throttle position, fuel injection mass and timing, EGR valve position to control flow of recirculated exhaust gases, glow-plug operation, and control of intake and/or exhaust valve timing, phasing, and lift, on systems so equipped. The control module is adapted to receive input signals from the operator (e.g., a throttle pedal position and a brake pedal position) to determine the operator torque request and from the sensors indicating the engine speed (RPM) and intake air temperature (TIN), and coolant temperature and other ambient conditions.
The exemplary engine configuration described in
On-board processing or processing by computational resources in the vehicle of vehicle operation enables control of pre-lubrication on the basis of vehicle history and operator specific history. For example, pre-lubrication control can be modulated based upon certain parameters, such as but not limited to: ambient temperature; engine temperature measured by coolant temperature; oil temperature; contamination of the oil estimated by the span since the last oil change; contamination of the oil by water and fuel contamination, estimated, for example, by analysis of short-trip driving patterns that fail to purge the oil of contaminants typically boiled off; engine mileage; estimated state of engine wear based upon analysis of engine metrics such as efficiency and exhaust content; time since last operating cycle ended; and oil weight (5W30 versus 10W40, for example). An algorithm can be utilized to estimate the effects of these factors upon the state of the engine at the next start-up event and the incremental damage that is likely to occur. Depending upon the perceived risk to the engine, control module 5 modulates the initiation or implementation of pre-start-up injections to compensate and avoid engine damage. For instance, control module 5 can command pre-lubrication events, modulate the amount of oil injected during the next start-up event, or command a delay during the next ignition cycle to allow adequate pre-lubrication based upon the aforementioned factors. Additionally, vehicle specific operating patterns can be utilized to command pre-lubrication event, for example in accordance with a recognized calendar day pattern based on vehicle starting history. For example, if control module 5 analyzes start-up data through an algorithm and determines that the vehicle is started certain weekdays within a certain time span, the algorithm can command a pre-lubrication event thirty minutes before this time span, thereby reducing the engine wear incurred during these start-ups. Similarly, if control module 5 determines that start-ups in the afternoon occur at varying times and involve very short warm up times, the algorithm of control module 5 can command sporadic pre-lubrication events to compensate for this perceived trend. In another example, a vehicle could be programmed with an initial setting indicating that the vehicle had not yet been delivered to the customer. Under this pre-delivery or unsold vehicle status setting, the vehicle could operate under a protective pre-lubrication scheme, with more frequent timed pre-lubrication events and with programmed ignition delays to allow for oil injection into cylinder 20 in the event of an ignition command. Such protective measures could be implemented incrementally or could be part of a unified protection mode. Additionally, command module 5 can adjust for perceived opportunities, such as the vehicle receiving power from an engine block heating device, and utilize the power source by pre-lubricating in instances where, under battery power, pre-lubrication might not be initiated to conserve battery power. It should be appreciated by those having ordinary skill in the art that the application of the aforementioned factors to the control of pre-lubrication events can have a multitude of embodiments and usages, and the disclosure is not intended to be limited to the specific examples described herein.
Wireless communication and satellite telemetry devices enable methods of pre-lubrication control requiring detailed location information. For example, weather reports can be downloaded through wireless communication devices and lubrication initiation modifiers can be adjusted to compensate for the reported temperatures in the area of the vehicle. The region in which the vehicle is operating can additionally be taken into account, for example, if the vehicle is operating near a coastline where increased humidity is likely or in a desert where sand contamination is likely, lubrication initiation modifiers can be adjusted to compensate for the effects upon engine wear and oil behavior. Location specific information can be utilized to modulate pre-lubrication parameters. For example, a vehicle tracked by GPS to be in a dealer's lot or operated in a certain manner consistent with dealer staging operations may be assumed to be in a dealer's inventory and is subject to deal staging operations as described above. Similarly, a vehicle tracked by GPS to be in a rental lot or at an operator's known place of work might be subject to particular driving patterns, and lubrication initiation modifiers can be adjusted to compensate. Alternatively, a control module can utilize the behavior of cellular tower signals, radio tower signals, or other signals capable of analysis to estimate location and likely operating behavior.
Remote processing of vehicle operation and communication with the vehicle enables pre-lubrication on the basis of a number of factors. Factors available from the vehicle and from location data can be coordinated and analyzed by remote processing to command and modulate pre-lubrication events. For instance, in order to avoid aforementioned wear associated with dealer staging, a remote processing system can look for large numbers of similar vehicles parked in a single lot or look for particular configurations of vehicle parking indicative of dealer lots and adjust pre-lubrication schemes as discussed above to mitigate driving behaviors inherent to dealer staging. Remote processing in this manner also allows for complex analyses to be performed and updated by control of the remote algorithm. For instance, emission controls, alternative fuels, and regulation of additives create changes in oil and fuel products made available to the consumer. Changes in composition to oil or fuel could have impacts to the vehicle unforeseen at the time of vehicle manufacture, and analysis and control by remote algorithms of pre-lubrication events can be utilized to compensate for such changes.
Additionally, remote processing in communication with the vehicle allows the tracking of registered operators across vehicles in communication with the remote processing. For instance, a vehicle owner, registered for his own vehicle and tracked for any of a number of unrelated functions, such as GPS map functions, radio preferences, and seat positions, can at the same time be monitored for habitual behaviors such as vehicle start-up times and likely vehicle warm up times. When the registered operator utilizes another vehicle, for example, by renting a vehicle on vacation, the remote system can adjust the pre-lubrication behaviors for the particular operator. Additionally, an operator can create a profile on the remote system regarding operating preferences. For example, an operator concerned about engine wear and unbothered by a delayed ignition cycle can program pre-lubrication for vehicles used by that particular operator. Identification of a registered operator can be accomplished by many methods known in the art, including a unique identifying device embodied in such devices as a key, a key chain, a keyless entry device, or an ID card; voluntary operator identification through a driver interface device asking for such information as a name or an I.D. number; biometric identification through such methods as fingerprinting or retinal scans; or other methods known in the art to identify a particular person.
Control reactions available to control module 5 to compensate for factors or pre-lubrication requirements are described in detail throughout this disclosure, and include the control module commanding timed oil injections, oil injections at or prior to times of expected start-up, oil injections in response to some impetus, and commanded delays to start-up to allow pre-injection, where necessary. Control module 5 may further modulate commanded oil injections by means described throughout this disclosure including increasing or decreasing amounts or frequency of oil injections, modulating the spray pattern of the oil injected into the engine through either modulation of the voltage applied to electric oil pump 50 or through a controllable nozzle 65, or preheating nozzle 65 to facilitate the application of oil to cylinder 20.
Aforementioned algorithms utilized by control module 5 or by remote systems may take many forms. An algorithm can be programmed with particular parameters and behaviors keyed to specific inputs, such as the inputs from in-vehicle sensors or known available GPS signals, and the algorithm can be programmed to respond with set responses. In the alternative, those having ordinary skill in the art will appreciate that machine learning algorithms utilizing fuzzy logic or neural networks or other adaptive programming can be used to adapt the algorithm to a wide variety of input and vehicle behaviors. The algorithm utilized by control module 5 or by remote systems may take many forms and is not intended to be limited to the specific embodiments described herein.
The disclosure has described certain preferred embodiments and modifications thereto. Further modifications and alterations may occur to others upon reading and understanding the specification. Therefore, it is intended that the disclosure not be limited to the particular embodiment(s) disclosed as the best mode contemplated for carrying out this disclosure, but that the disclosure will include all embodiments falling within the scope of the appended claims.
