The present disclosure relates to a method of controlling and engine of a vehicle equipped with engine idle stop or idle start-stop technology.
This section provides background information related to the present disclosure which is not necessarily prior art. Select present day vehicles may be equipped with engine idle stop (“EIS”) technology, which is also known as idle start-stop (“ISS”) technology. An ISS system may be configured to stop an engine of a vehicle during time periods of non-useful engine idle. Time periods of non-useful engine idle may be experienced when a vehicle stops in traffic and the vehicle's engine idles until the vehicle once again moves, or when a vehicle is stopped at a stop sign, stopped in traffic, stopped at a drive-through window, or at a railroad crossing. Other time periods of non-useful engine idle may exist. However, such present day ISS systems are not without their share of limitations. For instance, some ISS systems may stop a vehicle engine based only on a status of a combination of vehicle parameters or events. Such parameters may include when a brake pedal is pushed, when an accelerator pedal is not being pushed, when a battery of a vehicle is charged a prescribed degree, when a temperature of discharge air of an air conditioning system is satisfactory, and when vehicle speed is zero. The limitation of such ISS systems is that they do not take into consideration a “fuel penalty” required to restart the vehicle engine after the engine has been stopped. The additional fuel required to restart the vehicle after it has been stopped, as opposed to letting the engine idle for the amount of time that the engine was actually stopped, may be an amount of fuel equal or exceeding that amount of fuel combusted during an engine running time range of 10-20 seconds. Moreover, electrical energy may be wasted during restarting an engine since an engine starter consumes electrical energy to restart the engine. The electrical energy consumed during restarting will be restored by a vehicle charging system using electrical energy generated through fuel combustion.
What is needed then is a method of controlling an engine idle start-stop (“ISS”) system that determines whether an engine should be turned off and then restarted, or remain on, in order to maximize fuel efficiency.
This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features. A method of controlling an internal combustion engine of a vehicle may entail turning on the internal combustion engine, determining that a brake pedal of the vehicle is applied, determining that an accelerator pedal of the vehicle is not applied, determining that a drive battery or batteries of the vehicle are adequately charged, determining that an air temperature of air coming from an air conditioning unit is within a predetermined range, determining that a humidity level of air coming from an air conditioning unit is within a predetermined range, and inquiring whether a first predetermined quantity of data samples exists in memory that correspond to a specific time of day, of a specific day of the week, of a specific month of the year, for a specific GPS location. Such data samples may pertain to a specific turn signal direction for a specific time of day, for a specific day of the week, for a specific month of the year, for a specific GPS location.
Moreover, the method of controlling an internal combustion engine may further entail inquiring whether a second predetermined quantity of data samples exists in memory for a specific time of day of any day of the week for a specific GPS location. The method of controlling an internal combustion engine may further entail inquiring whether a third predetermined quantity of data samples exists for any single, specific time of day for any day of the week for a specific GPS location. The method of controlling an internal combustion engine may further entail inquiring whether a fourth predetermined quantity of data samples exists as downloadable data from a real time wireless network, as opposed or in addition to data that resident in on-board, vehicle memory. Depending upon the result of the above inquiries, the method of controlling an internal combustion engine may entail turning off the internal combustion engine.
The method of controlling an internal combustion engine may entail inquiring if a probability of a physical stop of the vehicle is greater than a predetermined probability, then calculating a median stop time value, and then inquiring whether a time to a median vehicle stop position plus a median stop time is greater than the idle restart penalty of the internal combustion engine.
Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.
The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.
Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings.
Example embodiments will now be described more fully with reference to
Data collected in the above-described scenario may be set to expire or be deleted from memory at prescribed or predetermined time periods from when it is collected. Alternatively, data may be deleted from memory at particular dates, such as monthly, annually, etc. in an automatic fashion, without human intervention to directly cause such deletion absent some initial set up or programming of when data should be deleted. Predetermined time periods may be set by the user of a vehicle based upon a general comfort level with using data of a certain age. Older data may reduce the accuracy or usefulness of the idle-stop logic if driving habits evident with a certain vehicle change over time. In other instances, the age of data will not affect proper or desired operation of the idle-stop logic.
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In still yet another scenario, assuming vehicle 10 approaches the same stop sign at a location that is known by the memory 34 of GPS module 36, engine 12 of vehicle 10 may be turned off as vehicle 10 is approaching the stop sign but before vehicle 10 actually stops at the stop sign. That is, an on board computer knows how much time the vehicle takes to move from a predetermined GPS location before the stop sign until the vehicle reaches the stop sign. Thus, the on board computer may turn off the engine 12 of vehicle 10 before vehicle 10 reaches the stop sign to conserve fuel on the vehicle's approach to the stop sign. Moreover, fuel may be conserved during the subsequent stop of the vehicle at the stop sign since the engine is still not turning. In such a scenario, the computer knows from memory 34 that the fuel conserved during the coasting to the stop sign plus the fuel conserved during the time the vehicle is stopped at the stop sign, and taking into consideration a restart penalty, is greater than the fuel consumed if the engine is turned off at any other time in approaching the stop sign or while stopped at the stop sign. Moreover, the fuel conserved during the coasting to the stop sign plus the fuel conserved during the time the vehicle is stopped at the stop sign, is greater than if the engine where not turned off, but left to idle, even when the engine restart penalty is taken into consideration.
Thus, teachings of the present disclosure may incorporate a variety of data, each corresponding to a particular and specific geographic location of a vehicle, such as a geographic location of a vehicle. For instance, memory 34 may store data related to: one stop event or multiple “stop events” that may be used to determine the probability of a vehicle stop event or a vehicle coast event; length of time of a stop event that may be used to determine the median length of time of stop events in a particular zone, area or particular location; vehicle stop position or stop location of vehicle 10 that may be used to determine if an engine 12 can be turned off prior to vehicle 10 actually stopping; date of vehicle stop that may be used to arrive at more specific stopping information of vehicle 10; time of day of vehicle stop that may be used to arrive at more specific stopping information of vehicle 10; which turn signal indicator is activated (e.g. left or right) or if no turn signal indicator is activated, and at what geographic location such activation or non-activation occurs; and length of time of turn signal activation since left turns on average generally take longer to complete than right turns since crossing oncoming vehicles usually occurs. Thus, each time vehicle 10 stops, the length of the corresponding stop time at the corresponding GPS location, the calendar date (i.e. time, time block, the day of the week, month and year) of the vehicle stop, and geographic location will be stored in memory, such as memory 34. Geographic stop locations of vehicle 10 may include not only stop signs, but any conceivable location that a vehicle may stop, including but not limited to stop lights, also known as traffic lights, train crossings, also known as rail road crossings, on any road in any type of traffic (e.g. light or heavy), drive thru windows, etc.
As the idle-stop system of the present disclosure becomes more experienced, that is, as the memory 34 is filled with data representative of geographic locations of vehicle stops and duration of vehicle wait times at such geographic locations before moving again, as described above, fuel economy of vehicle 10 will improve and tail pipe emissions will be reduced per mile driven and for the life of vehicle 10, as compared to a vehicle without the benefit of teachings of the present disclosure. Continuing, teachings of the present disclosure instruct engine 12 when to stop turning and when not to stop turning when a vehicle makes a temporary stop at a location (e.g. traffic light, stop sign, railroad track, etc.) in route to a destination.
As examples, in accordance with idle-stop system teachings of the present disclosure, engine 12 may be instructed to stop turning (i.e. be turned off) as soon as a brake pedal 48 of vehicle 10 is contacted or pressed. When a brake pedal 48 is being pressed, GPS module 36 will know the changing location of vehicle 10, such as if vehicle 10 is approaching a location where vehicle 10 typically makes a complete stop, or at least coasts with engine 12 at idle. By stopping engine 12 as vehicle 10 is coming to a stop, as opposed to stopping engine 12 after coming to a stop, engine 12 will consume less fuel. That is, fuel is saved as vehicle 10 coasts toward a stop location without engine 12 operating compared to an equivalent engine that is not turned off. Moreover, additional fuel is saved since when vehicle 10 finally does stop as a result of application of brake pedal 48, engine 12 is already off. This is different from an engine in a vehicle that may be turned off after an elapse of a time period (e.g. 2-5 seconds) after the vehicle stops. In accordance with present teachings, electric power steering, as opposed to an engine-driven hydraulic system, will ensure that vehicle 10 maintains its steering system when engine 12 is turned off. Similarly, electric power brakes, or adequately sized vacuum reservoirs, will ensure that vehicle 10 maintains its braking system when engine 12 is turned off. If stopping vehicle 10 is no longer necessary as vehicle 10 approaches a potential geographic stop location, for whatever reason, a driver simply need touch or press accelerator pedal 50.
In another example of a data based intelligent engine idle stop system in accordance with present teachings, GPS module 36 in conjunction with GPS satellite 38 detects that vehicle 10 is a certain, predetermined distance away from an intersection and approaching the intersection. Besides an intersection, other geographic stop locations are known, as mentioned above. When a driver touches brake pedal 48 with his or her foot, GPS module 36, or other computer working in conjunction with GPS module 36, calculates based on previously saved or previously loaded data in memory, the probability of vehicle 10 stopping at the intersection. If the probability of a vehicle stopping at the intersection is high enough, the amount of time (i.e. time period in seconds or minutes) to the median stopping point using the current or real-time speed of vehicle 10 and the average deceleration are calculated. The acceleration and deceleration used in conjunction with the present teachings may be measured with an accelerometer, or they may be data based (e.g. read from stored memory). The GPS module 36 or computer performing the associated calculations may then add the calculated vehicle coast time with the median stop time and calculate if engine 12 will be more fuel efficient by leaving engine 12 on (i.e. running or turning) or by turning off engine 12. Thus, to illustrate the fuel savings for the scenario described in the above example, teachings of the present disclosure may calculate a four second coast to the intersection to the point where a vehicle may have to stop, and then a ten second engine restart fuel penalty. Thus, by turning off the engine at the beginning of the four second coast, such as when brake pedal 48 is contacted, and eliminating the time a vehicle may idle while stopped before turning off the engine, at least four seconds of fuel combustion by a vehicle engine is eliminated. While all vehicles have an engine start or restart fuel penalty, by eliminating engine fuel combustion before a vehicle comes to a complete stop at an anticipated stopping location and while a vehicle engine idles while stopped, fuel may be saved.
At step 86, logic of flowchart 74 inquires if memory 34 presently holds a data sample of a precise time (e.g. a.m. and/or p.m.) for a precise day of the week (e.g. Monday, Tuesday, Wednesday, Thursday, Friday, Saturday, Sunday), for a precise month of the year (e.g. January, February, March, April, May, June, July, August, September, October, November, December) for a specific geographic location pertaining to a geographic location identified by GPS module 36 in conjunction with GPS satellite 38. Step 86 may further inquire if a specific quantity of sets of data (i.e. a set being all three of a time of day, a day of the week and a month of the year) exist for a specific geographic location. If the result of the inquiry at step 86 is “no,” then the logic proceeds to step 88.
At step 88, the logic inquires if memory 34 presently holds a data sample of a precise time (e.g. a.m. and/or p.m.), for any day of the week (e.g. Monday, Tuesday, Wednesday, Thursday, Friday, Saturday, Sunday) for a precise month of the year (e.g. January, February, March, April, May, June, July, August, September, October, November, December) for the specific geographic location pertaining to step 86. Step 88 may further inquire if a specific quantity of sets of data (i.e. a set being all three of a time of day, a month of the year, but for any day of the week) exists for one or more specific geographic locations. If the result of the inquiry at step 88 is “no,” then the logic proceeds to step 90. At step 90, the logic inquires if memory 34 presently holds a data sample of any time (e.g. a.m. and/or p.m.), for any day of the week (e.g. Monday, Tuesday, Wednesday, Thursday, Friday, Saturday, Sunday) for any month of the year (e.g. January, February, March, April, May, June, July, August, September, October, November, December) for the specific geographic location pertaining to step 86. Step 90 may further inquire if a specific quantity of sets of data (i.e. a set being all three of a time of day, a month of the year, and day of the week) exists for one or more specific geographic locations. If the result of the inquiry at step 90 is “no,” then the logic proceeds to step 92.
At step 92, the logic further inquires if a specific quantity of sets of data (i.e. a set being all three of a time of day, a month of the year, and day of the week) exists for a specific geographic location. Moreover, the logic inquires if real time wireless network data exists. That is, GPS module 36 may communicate wirelessly to a database 39 (
If the result of any of the inquiries of steps 86, 88, 90, 92 is “yes,” then the logic proceeds to step 96, which inquires whether the probability of a stop is higher than a predetermined value. If the result of such an inquiry is “no,” then the logic proceeds to step 102 where the logic instructs ECM 14 to not stop engine 12. However, if the result of the inquiry at step 96 is “yes” then the logic proceeds to step 98 where the logic instructs a computer, resident in GPS module 36 or ECM 14, for example, to calculate a median stop time value. The logic then proceeds to step 100, which inquires if a sum of a time to median stop position plus median stop time is greater than the idle restart penalty. If the answer to such inquiry of step 100 is “yes,” then the logic proceed to step 94 where ECM 14 may instruct engine 12 to be turned off; however, if the answer to such inquiry of step 100 is “no,” then the logic proceed to step 102 where ECM 14 may instruct engine 12 not to be turned off. Upon reaching either step 94 or 102, logic of flowchart may then begin again at step 76.
Presented in slightly different words, a method of controlling internal combustion engine 12 of vehicle 10 may first entail turning on the internal combustion engine 12. Next, and with reference to flowchart 74, determining that a brake pedal 48 of vehicle 10 is applied (step 78), determining that accelerator pedal 50 of vehicle 10 is off or not applied (step 80), determining that the battery 18 of vehicle 10 are adequately charged (step 82), and determining that an air temperature and a humidity level of air coming from an air conditioning unit is within a predetermined range (step 84), the logic may then proceed to step 86. Step 86 involves inquiring whether a first predetermined quantity of data samples exists in memory 34 and more specifically, whether the first predetermined quantity of data samples corresponds to a specific time of day, of a specific day of the week, of a specific month of the year, for a specific GPS location. That is, when vehicle 10 approaches a potential stop location, such as may be known from stored data within memory 34, or when vehicle 10 actually stops at a location, the specific time of day (e.g. 2 o'clock), the specific day of the week (e.g. Monday), the specific month (e.g. January) of the year (e.g. 2010), and specific GPS location (e.g. latitude and longitude, street address, cross-streets intersection, etc.) corresponding to the vehicle stop are recorded into memory 34.
If a predetermined quantity of memory samples (i.e. a predetermined preferred number of stops) in accordance with step 86, do not exist, the method of control proceeds to step 88 where a broadening of criteria occurs. That is, the logic proceeds to inquiring whether a predetermined quantity of data samples (e.g. vehicle stops) exists in memory for the specific time of day of the present vehicle stop, but for any day of the week (e.g. Tuesday, Wednesday, etc. as opposed to Monday) for the specific GPS location of the vehicle stop. If the predetermined quantity (e.g. 10 vehicle stops) is not satisfied at step 86 and step 88, which means that ten vehicle stops are not within memory 34 for a prescribed GPS location, the logic then proceeds to step 90 by inquiring whether a predetermined quantity of data samples exists for any single, specific time of day for any day of the week for the specific GPS location of the stop or anticipated stop of vehicle 10. Still yet, if the requirements or inquiries made at steps 86, 88 and 90 are not met, the logic proceeds to step 92 where the method of controlling an internal combustion engine 12 inquires whether a predetermined quantity of data samples exists as downloadable data from a real time wireless network. That is, instead of the inquiries of steps 86, 88 and 90 being met by data resident in memory 34 of vehicle 10, that is as on-board data of vehicle stops, database 39 may be contacted via satellite 38, or alternatively through other wireless means such as cell phone towers, to see if any of the inquiries of steps 86, 88 and 90 may be satisfied. That is, non on-board data may be used. Such non on-board data may be stored by other vehicles and correspond to particular, specific GPS locations.
If the result of inquiries made at steps 86, 88, 90 and 92 is “no,” meaning that data does not exist, then the engine 12 is turned off, as is noted at step 94. However, if a result of any of the inquiries made at steps 86, 88, 90 and 92 is “yes,” meaning that data satisfying the respective inquiry does exist in memory 34, the logic proceeds to step 96 where an inquiry is made as to whether a probability of a physical stop of the vehicle is greater than a predetermined probability, which may be set by a vehicle user or vehicle manufacturer. If the result of the inquiry made at step 96 is “yes,” then the logic proceeds to step 98 where calculating a median stop time value is performed. A median stop time value is that median period of time that a vehicle needs to stop at a known stopping location, which may be calculated from times of known stops and stored in memory 34. Upon such calculation at step 98, the logic proceeds to step 100 where the logic inquires whether a time to a median stop position plus a median stop time is greater than the idle restart penalty.
More specifically, regarding step 100, a median stop time, as explained in conjunction with step 98, may be combined with a time to a median stop position. That is, time to a median stop position may be that time as measured from when a vehicle begins to decelerate or slow down until such vehicle actually stops at the known stopping location. The known stopping location may be a median stopping location. In one scenario of step 100, a vehicle GPS will know a stop location or position of vehicle 10 from memory 34. In addition to known GPS coordinates of a stop location, also known are a speed of vehicle 10 and a position to vehicle 10, from which a distance from a present location of vehicle 10 to the known stop position may be calculated. Thus, a time to median stop position may be calculated. The on-board computer may then add the median stop time, that is, how long the vehicle will be stopped on average, to the time to the median stop position. If the result at the inquiry at step 100 is “yes,” then the engine is turned off at step 94. However, if the result of the logic at step 100 is “no,” then the engine is not turned off, as reflected in step 102.
The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Example embodiments are provided so that this disclosure will be thorough, and will fully convey the scope to those who are skilled in the art. Numerous specific details are set forth such as examples of specific components, devices, and methods, to provide a thorough understanding of embodiments of the present disclosure. It will be apparent to those skilled in the art that specific details need not be employed, that example embodiments may be embodied in many different forms and that neither should be construed to limit the scope of the disclosure. In some example embodiments, well-known processes, well-known device structures, and well-known technologies are not described in detail. Moreover, the method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order discussed or illustrated, unless specifically identified as an order of performance. It is also to be understood that additional or alternative steps may be employed.