Patent Application
20080042820
The novel features believed characteristic of the invention are set forth in the appended claims. The invention itself however, as well as a preferred mode of use, further objects and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying drawings, wherein:
Referring now to
Engine controller module (ECM) 20, as already discussed, is the local controller which collects most of the required data. ECM 20 is connected to group 203 of engine sensors 203A-E, which include an oil dielectric sensor 203A, an oil level sensor 203B, an oil temperature sensor 203C, a coolant temperature sensor 203D and a crank position sensor 203E. Oil dielectric sensor 203A and oil level sensor 203B may be implemented using a single capacitive sensing element.
Control actuator group 204 includes controllers and counters for events under the control of ECM 20. An ON/OFF controller 204C indicates whether the engine 19 is running. ECM 20 will provide control signals to injector control 204B. Timing information for the injector control signals of course requires piston position information, which is typically derived from crankshaft position. This information comes from a crankshaft position sensor 203E. ECM 20 also has control over fuel flow 204D and a counter tracking cylinder ignition events 204A.
The present optimization algorithm can provide the vehicle operator a distance estimate until recommended service for each component/fluid. Accordingly, distance traveled is tracked. Vehicle odometer functions complementary to this operation may be combined with a vehicle's anti-lock brake system (ABS) controller 22, which has wheel speed sensors 23 associated with each of the vehicle's wheels. Wheel speed signals may be combined to generate velocity and distance traveled data. Vehicle speed and distance traveled may alternatively be measured by a transmission tachometer 17. The tachometer signal may be processed with transmission controller 16 by the engine controller 20, which receives the signal over bus 18 enabling determination of vehicle speed, and its integral, distance traveled.
The occurrence of service is preferably noted by the truck operator or a service technician using interval reset inputs 13 to enter data relating to the service. The interval reset inputs 13 may be handled a number of ways. They may be coupled through instrument and switch bank controller 12 to data bus 18 as illustrated. Operators may find it more convenient to have a service technician use a handheld device or personal computer interface to the network bus 18 to enter service data. Data input by an operator or technician indicates items serviced and results in reset of distance traveled and other, related tracking variables.
A service interval display panel 25 (which may be a multi-purpose display) under the control of gauge cluster controller 14 may be used to indicate to an operator the distance and date currently estimated until the next required service and whether the distance and date have been locked in. Alternatively a percentage remaining indication may be provided. The service interval optimization program may be executed locally by an on board microcomputer 80 or remotely by a remote telematics portal and server 265. Where executed locally the service interval optimization algorithm is preferably stored in memory 31 and accesses look up tables 33. Remote execution is effected over a wireless link implemented by wireless transceiver 82, coupled to microcomputer 80 and wireless transceiver 282, coupled to remote telematics portal 265, which has local access to a local copy 267 of the service scheduling or interval optimization algorithm. Remote execution of the algorithm aids in coordinating service scheduling across a fleet of vehicles, and potentially can be used as a guide for routing a vehicle to place it near a service center at the time service needs are anticipated.
A representative interval optimization algorithm 300 is illustrated in
Several variables are referenced in the description of the algorithm 300. To avoid confusion the variables are defined here. The “manufacturer's recommended service interval” is an exogenous value which may be expressed in units of distance, liquid measure, time, weight, etc. It reflects a manufacturer's best estimate, usually empirically determined of the service life of a vehicle component or fluid. The “minimum service interval” is a value designated in units of distance derived from one of a selected plurality of manufacturers' recommended service intervals. Because some of the manufacturers' recommended service intervals are defined in terms other than distance the derivation step includes converting all intervals to distance for comparison purposes. Obviously, the intervals defined in terms other than distance will return varying values for distance depending upon how the vehicle is used. The “vehicle usage factor” is a unit-less value derived from vehicle operating variables and is used as a weighting factor when determining the recommended service interval. The “next recommended service date” is exogenously provided by an independent oil change algorithm.
At step 301 calendar time is checked and if the vehicle has been inoperative for a long period, advise service for items such as tire inflation, fluid changes, etc. At step 302 a lookup operation is performed to recover a manufacturer's recommended service interval for a component or fluid of interest. Next, the process of determining a service interval for the vehicle occurs. At step 304 the vehicle's minimum service interval is determined. The minimum service interval, viewed simply, is the lesser of the recommended service interval for the engine oil and the recommended service interval for chassis lubrication. The determination of the these intervals is a non-trivial step, since it does not involve simply looking up a fixed distance interval for engine oil changes.
Referring to side box 306 the minimum service interval is defined as the lesser of the engine oil interval and the chassis lube interval. At the time of writing this application, the chassis lube interval is simply the manufacturer's recommended maximum distance. The situation with regard to engine oil change regimen is more complex.
Temporarily referring to
At step 402 the routine of
Steps 406, 408 illustrate determination of a distance limit based upon a limit in terms of hours of operation. The number of hours the engine has been on is subtracted from a limit interval. The rate of hours per distance unit traveled is multiplied against the remainder to convert the limit into distance. Finally, at step 410, the four available limits, distance between oil changes, distance between chassis lubrications, and the distance limit projections for oil changes based on hours of operation and fuel consumption can be compared and a minimum selected and returned to the main line of the program 300. It may be seen that the limit is dependent upon the character of use to which the vehicle 105 is put. Extended periods at idle tend to make the hours of operation variable the controlling one. Heavy loads, stop and go driving and physically difficult operating conditions tend to make fuel consumption the limiting variable. The minimum service interval may be made subject to constant update until a relatively short period is left until service is anticipated.
Once a minimum service interval is returned at step 304, the operating variables of interest with respect to a particular component/fluid are retrieved at step 308. As previously indicated these may include for anyone item one or more of the following: vehicle distance traveled; engine hours; engine idle hours; vehicle weight; fuel consumed; among the possibilities. A recommended service interval for each component/fluid is generated from the recommended service interval based on a characterization of vehicle usage. The characterization is preferably objective and is represented by a “vehicle usage factor” calculated at step 312 which is multiplied by the manufacturer's recommended service interval in step 310 to determine a recommended service interval for the item. The default value for the vehicle usage factor is obviously one. Since hard use should reduce the service interval a characteristic vehicle usage factor for “hard use” will be less than one while light use will be characterized by a value greater than one. The vehicle usage factor is determined separately for each component/fluid of interest.
The operation of step 312 may be represented by an equation used to determine each vehicle usage factor:
V
UF
=G(C1*Norm/Weight)+(C1*BMEPN/BMEP)+(C2*TEMPN/TEMP)+ . . . )
Where C is the weight given each factor, and “Norm” equals a default vehicle weight and “Weight” means measured weight, BMEP means brake mean effective pressure (both normative and measured), and TEMP refers to measured and normal operating temperature. The normative value is always the numerator of the fractions. Other factors are typically considered and included in the equation by the same rule, with appropriate adjustment of the weighting factor.
Next, at step 314, it is determined whether the recommended service interval (that is the result of the evaluation of step 310) is a whole number multiple of the minimum service interval of step 304. Manufacturer's recommended service intervals are established so as to at least equal the possible minimum service intervals. Hence a value of at least 1 should be returned for N. Should N be a whole number execution advances along the YES branch to step 318 to determine a recommended service interval for the component of interest. Obviously where N=1 the service interval will coincide with the minimum service interval, in other words, service of the component/fluid is pulled into the next scheduled service at step 324, which is retrieved from an engine oil change algorithm 325. The item is then scheduled for service (by comparing distance left until service with the daily mileage rate (step 326)) which is used to adjust the next recommended interval (which is added to the next recommended service date returned by the oil change algorithm). Step 328 relates to checks of override items. As already noted, an indication of fuel filter blockage or air filter blockage results in generation of an indication of the need for immediate service.
The “next recommended service date” is exogenously provided by an independent engine oil change algorithm 325 which may be implemented as described in U.S. Pat. No. 6,513,368.
Returning to step 314, it is perfectly possible, indeed likely, that N will not be a whole number integer. Accordingly a NO path from step 314 to step 320 is provided. If vehicle operating variables indicate heavier than average usage N is reduced to the nearest whole number integer and processing follows step 318 as before, as indicated along the YES path from step 320. Otherwise processing continues along the NO path to step 322 where it is provided that N is increased to the next whole number integer (i.e. at least 2) which results in the recommended service interval being modified by multiplication by a positive whole number integer equaling at least 2.
The invention provides for the relative optimization of service intervals for various vehicle components/fluids.
While the invention is shown in only one of its forms, it is not thus limited but is susceptible to various changes and modifications without departing from the spirit and scope of the invention.
