TECHNICAL FIELD

[0001] The present disclosure relates to restarting an internal combustion engine. More particularly, the present disclosure relates to a system and a method of estimating an engine stop location to enable a quick restart of the engine.

BACKGROUND

[0002] Internal combustion engines generate mechanical energy from a chemical energy input (e.g., fuel such as gasoline, diesel, natural gas, etc.). As fuel costs have increased, consumers have demanded low fuel consumption engines. As a result, hybrid and electric vehicles have become increasingly popular due to their relatively low fuel consumption. Often, however, hybrid and electric vehicles are not considered by consumers as having the power necessary for various applications (e.g., semi-tractor trailer applications). Accordingly, traditional fuel-powered engines remain prevalent. However, combustion characteristics have been and are being studied to determine a minimum amount of fuel necessary for combustion to occur in various types of engines.

[0003] Regardless of the engine type, for combustion to occur, the engine must be operating at a sufficient speed (revolutions-per-minute, "RPM"). For a fuel-injected engine, the fuel must also be injected when the piston is at a location that allows for combustion. To achieve the necessary speed, starter motors, coupled to a flywheel of the engine, turn or spin a crankshaft and a camshaft of the engine. This causes the pistons to actuate within each piston's cylinder. Prior to top dead center, a fuel injector injects fuel into the cylinder to allow the upward moving piston to compress it and cause ignition of such fuel (i.e., a compression-ignition engine). To prevent the likelihood of engine knock, the location of the piston within the cylinder is determined such that fuel is provided at the proper timing. Once proper combustion occurs, the starter motor disengages from the engine and the combustion process itself drives the pistons to provide the mechanical power. SUMMARY

[0004] One embodiment relates to an engine position system, comprising a rotary engine position tone wheel; a sensor configured to obtain position data regarding a position of the rotary engine position tone wheel; and an engine control module. The engine control module is configured to: receive an engine stop command, the engine stop command configured to shut down an engine; receive the position data from the sensor; determine a first instance of oscillation of the rotary engine position tone wheel while the engine is shutting down; estimate a stop position of the rotary engine position tone wheel based on the first instance of oscillation; store the estimated stop position of the rotary engine position tone wheel; receive an engine restart command; and provide a command to restart the engine based on the estimated stop position.

[0005] Another embodiment relates to an engine position system comprising an engine control module. The engine control module is configured to receive an engine stop command, the engine stop command configured to shut down an engine; receive the position data; determine a first instance of oscillation of a rotary engine position tone wheel while the engine is shutting down; estimate a stop position of the rotary engine position tone wheel based on the first instance of oscillation; store the estimated stop position of the rotary engine position tone wheel; receive an engine restart command; and provide a command to restart the engine based on the estimated stop position.

[0006] Still another embodiment relates to tangible, non-transitory computer-readable storage medium having machine instructions stored therein, the instructions being executable by a processor to cause the processor to perform operations including: receiving an engine stop command, the engine stop command configured to shut down an engine; receiving position data from a single directional sensor; determining a first instance of oscillation of a rotary engine position tone wheel while the engine is shutting down; estimating a stop position of the rotary engine position tone wheel based on the first instance of oscillation; storing the estimated stop position of the rotary engine position tone wheel; receiving an engine restart command; and providing a command to restart the engine based on the estimated stop position. [0007] These and other features, together with the organization and manner of operation thereof, will become apparent from the following detailed description when taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE FIGURES

[0008] FIG. 1A is a schematic diagram of an internal combustion engine system for a vehicle according to an example embodiment.

[0009] FIG. IB is a schematic diagram of an engine position system according to an example embodiment.

[0010] FIG. 2 is a flow diagram of a method of restarting an internal combustion engine according to an example embodiment.

[0011] FIG. 3 is a schematic diagram of camshaft wheel position in comparison to crankshaft wheel position according to an example embodiment.

[0012] FIG. 4 is a schematic diagram of camshaft wheel position as a function of crankshaft wheel position according to an example embodiment.

[0013] FIG. 5 is a graphical depiction of position data regarding crankshaft wheel position including an oscillation instance according to an example embodiment.

[0014] FIG. 6 is a graph of engine speed versus time for a plurality of restarts of a six- cylinder engine according to an example embodiment.

[0015] FIG. 7 is a graph of engine speed versus time for a plurality of restarts of a four- cylinder engine according to an example embodiment.

[0016] FIG. 8 is a schematic diagram of combustible event locations as a function of crankshaft wheel position according to an example embodiment.

DETAILED DESCRIPTION OF VARIOUS EMBODIMENTS

[0017] Referring to the figures generally, the various embodiments disclosed herein relate to systems and methods of estimating and remembering the engine stop location to enable a fast restart of the engine. To improve fuel economy, an internal combustion engine of a vehicle may shut down when at an extended stop while the ignition remains in the "on" position (i.e., an operator has not turned the key to an "off position). For example, when the vehicle is at a stop light, the driver of the vehicle may depress the brake pedal which shuts down the engine because the brake pedal is depressed for longer than a predetermined amount of time (e.g., longer than two seconds). Rather than continuous operation, periodic in-operation leads to fuel savings. However, to avoid extended stops before the engine restarts, engine restarts need to be relatively quick. Accordingly, the systems and methods disclosed herein provide a relatively quick restart of the engine.

[0018] Engine restart is a function of engine location and engine speed. A starter motor is used to turn the engine to achieve a sufficient speed. When the location is correct (i.e., where the piston is positioned in the cylinder, such as just before top dead center), fuel is injected to cause combustion. If fuel is injected at an inappropriate time (e.g., during the intake stroke), fuel may build up within the cylinder, which may prevent combustion and cause engine damage. Similarly, if engine speed is not sufficient, combustion may be unable to sustain engine operation. Thus, the speed and location need to be synced to enable proper combustion. More particularly, engine startup requires synchronization of the engine crankshaft and camshaft. The crankshaft controls actuation of the pistons and the camshaft controls actuation of the valves of the cylinder. After synchronization, the engine monitoring system may report engine speed and begin processing fueling/injection commands into the cylinders. Accordingly, engine startup requires rotation of the engine (using the starter), detection of the crankshaft wheel index (described herein), and correction of the engine "half cycle" (also described herein) based on the detection of the camshaft index before fueling/injecting commands are possible and sustainable combustion occurs.

[0019] The present disclosure provides for systems and methods of estimating and memorizing the engine stop location based on the dynamics/weighting of the engine to enable restart of the engine. The traditional indexing step is eliminated to enable a relatively faster engine restart. As described herein, when an engine is shutting down, the engine tends to oscillate before coming to rest. During shut down, a single directional engine position sensor is utilized to allow the engine control module to estimate the engine stop position based on the crankshaft wheel tooth number. The estimated engine location is memorized in a controller (e.g., engine control module) of the vehicle. When an operator initiates an engine restart (e.g., pressing the accelerator pedal and/or releasing the brake pedal), based on the estimated location, the controller controls the timing and location of the fuel injection events (i.e., which cylinder is injected with fuel and when) to achieve sustainable combustion at the next possible combustible event location. Accordingly, a relatively faster engine restart is achieved by foregoing the aforementioned synchronization process.

[0020] As used herein, the term "engine position" refers to the position of the crankshaft for an internal combustion engine, which is indicated by the position of a crankshaft wheel (e.g., a crankshaft wheel tooth number). Because the crankshaft wheel is coupled to the crankshaft, the rotation of the crankshaft is the same as that of the crankshaft wheel. The crankshaft is also coupled to the camshaft via, for example, a belt, such that the position of the crankshaft also corresponds with a specific position of the camshaft. In an internal combustion engine, the crankshaft is coupled to one or more pistons and the camshaft is in operative communication with one or more valves (e.g., intake valve) of the engine. Accordingly, the engine position includes various and different positions of the piston(s) and valves based on the position of the crankshaft and camshaft, respectively. For example, the position of the crankshaft wheel may indicate an engine position of bottom dead center for the piston of cylinder number three, top dead center for the piston of cylinder number two, and in between bottom and top dead center for the pistons of cylinder numbers one and four (four cylinder engine). This position may also indicate the position of the valves for each of the four cylinders. Accordingly, an engine control module may control fuel injecting/spark ignition for the cylinders based on this position. For example, the engine control module may ready the ignition coil (spark for a spark ignition engine) and/or fuel injector for cylinder number three as the piston begins its ascent to top dead center. As such, engine position includes the position of the crankshaft and camshaft based on the position of the crankshaft wheel.

[0021] Referring now to FIG. 1A, an internal combustion engine system 100 for a vehicle is shown according to an example embodiment. The internal combustion engine system includes an engine control module ("ECM") 130 powered by a battery 101. As shown, the ECM 130 may receive a plurality of inputs and is coupled to a variety of components with the system 100. The battery 101 is coupled to a motor 102 (i.e., a starter motor). As described above, the motor 102 engages with the engine 105 to rotate a crankshaft of the engine to start the engine 105. Rotation of the crankshaft of the engine causes a crankshaft position wheel 120 (FIG. IB) to rotate in sync with the crankshaft. During operation, at least one of the engine 105 and the motor 102 provide power to one or more vehicle accessories 104 (e.g., oil pump, air compressor, etc.). Additionally, the engine 105 provides mechanical power to a transmission 103 of the vehicle, which transfers the power to one or more wheels of the vehicle to enable movement of such vehicle.

[0022] The engine 105 may be of various sizes (e.g., four cylinder, six cylinder, etc.) and types. For example, the engine 105 may be a compression-ignition engine or a spark- ignition engine. For simplicity, the engine described herein is in regard to a compression- ignition engine. However, the methods and systems described and disclosed herein may also be applicable to a spark ignition engine.

[0023] Referring to FIG. IB, an engine position system 150 is shown according to an example embodiment. The engine position system 150 includes a sensor 110 and a rotary engine position tone wheel 120, communicatively coupled to the ECM 130. The rotary engine position tone wheel 120 corresponds with the position of the crankshaft. In one embodiment, the rotary engine position tone wheel 120 is structured as a crankshaft wheel 120 that is coupled to a crankshaft, which is connected to one or more connecting rods that are connected to one or more pistons of the engine 105. As the crankshaft rotates, the crankshaft wheel 120 rotates in sync with the crankshaft. Although described herein as a crankshaft wheel 120, the rotary position tone wheel 120 may include shutter blades, notches, protrusions, or any other type of device that generates an output signal from the sensor 110 as the wheel 120 rotates.

[0024] Communication between and among the components of the engine position system 150 (and engine system 100) may be via any number of wired or wireless connections. In one embodiment, a controller area network ("CAN") bus 140 provides the exchange of signals, information, and/or data among at least the components shown in FIGS. 1A-1B. CAN bus 140 includes any number of wired and wireless connections. For example, a wired connection may include a serial cable, a fiber optic cable, a CAT5 cable, or any other form of wired connection. In comparison, a wireless connection may include the Internet, Wi-Fi, cellular, radio, etc. [0025] Although depicted as ECM 130, the ECM 130 may also include a transmission control unit and any other control unit included in a vehicle (e.g., exhaust aftertreatment control unit, powertrain control module, etc.). Accordingly, the ECM 130 may be implemented as a general-purpose processor, an application specific integrated circuit (ASIC), one or more field programmable gate arrays (FPGAs), a digital signal processor (DSP), a group of processing components, or other suitable electronic processing components. Moreover, the ECM 130 may also include one or more memory devices. The one or more memory devices (e.g., RAM, ROM, Flash Memory, hard disk storage, etc.) may store data and/or computer code for facilitating the various processes described herein. Thus, the one or more memory devices may be communicably connected to the ECM 130 and provide computer code or instructions to the ECM 130 for executing the processes described in regard to the ECM 130 herein. Moreover, the one or more memory devices may be or include tangible, non-transient volatile memory or non-volatile memory. Accordingly, the one or more memory devices may include database components, object code components, script components, or any other type of information structure for supporting the various activities and information structures described herein. In operation, the ECM 130 receives one or more signals (i.e., position data) from the sensor 110. Based on the position data, the ECM 130 estimates the engine position to enable a quick restart of the engine.

[0026] Sensor 110 may be structured as a single directional sensor. Accordingly, the sensor 110 may monitor the position of the crankshaft wheel in one direction of rotation. In some embodiments, the sensor 110 is configured as a crankshaft position sensor. The crankshaft position sensor may be a hall effect sensor, an optical sensor, an inductive sensor or any other type of crankshaft position sensor. As a hall effect sensor, the sensor 110 may receive supply voltage from the battery 101, such that a constant voltage may be produced. The output voltage (i.e., a signal, such as a square wave) from the sensor 110 then varies based on position of the crankshaft wheel 120 (i.e., whether a tooth of the crankshaft wheel 120 enters the magnetic field of the sensor 110). The sensor 110 monitors the position and speed (corresponding to engine RPM) of the crankshaft wheel 120. The sensor 110 obtains position data regarding the position of the crankshaft wheel 120 and transmits the position data to the ECM 130. In some engine systems, a camshaft position sensor 210 may also be utilized to determine the position of the camshaft. In which case, the ECM 130 may also receive camshaft sensor position data 160 from the camshaft sensor 210. The sensor 110 may be mounted on the main crankshaft pulley, the flywheel, the camshaft, or on the crankshaft itself. In other embodiments, the sensor 110 may be in any position where the sensor 110 may monitor and detect the position of crankshaft (e.g., via rotary tone wheel 120).

[0027] As shown, the crankshaft wheel 120 is structured as a gear that includes a plurality of teeth 122. In certain other embodiments, the crankshaft wheel 120 may be structured in any manner that enables the position of the crankshaft to be monitored. In the example shown and described herein, the crankshaft wheel 120 is configured as a 60-2 gear (60 teeth with 2 teeth missing). The two missing teeth serve as an index for the crankshaft wheel 120. In traditional systems, the engine position sensor first must observe the index location prior to synchronizing the crankshaft with the camshaft to enable combustion and engine restart. Although the systems and methods described herein are in regard to the configuration of the crankshaft wheel 120 shown in FIG. IB, the same or similar systems and methods may be utilized with crankshaft wheels of all shapes (e.g., 12-2 (twelve teeth with two missing), 32-2, etc.).

[0028] Referring now to FIG. 2, a method 200 of estimating an engine stop position to allow quick restart of the engine is shown according to an example embodiment. In one embodiment, method 200 is implemented with the ECM 130. Accordingly, method 200 may be executed by one or more processors in the ECM 130.

[0029] Method 200 begins by the ECM 130 receiving an engine stop command (201). The stop engine command includes any command that turns the engine off while the ignition key stays in the "on" position. For example, the stop command may include depression of the brake pedal or the actuation of an "engine shut off button. In either event, the engine of a vehicle turns off, but the ignition key position remains on. Accordingly, power from the battery 101 is not disconnected. Thus, after the stop engine command is received by the ECM 130, the ECM 130 turns the engine of the vehicle off (or, actuates one or more shut down mechanisms to shut the engine down).

[0030] At process 202, the ECM 130 receives engine position data. The engine position data is detected by the single directional sensor 110 and corresponds with the position of the crankshaft wheel 120. In some embodiments, the crankshaft wheel position is based on tooth number. During engine operation, the camshaft wheel 200 rotates at half the speed of the crankshaft wheel 120. Thus, for two revolutions of the crankshaft wheel 120, the camshaft wheel 200 makes one complete revolution. All cylinders of the engine will fire (i.e., experience a combustible event) every two revolutions of the crankshaft wheel 120 and every one revolution of the camshaft wheel 200. This relationship is seen in FIG. 3. In FIG. 3, the "first half-cycle" (half rotation of the camshaft wheel 120) refers to the first revolution of the crankshaft wheel 120 and the "second half-cycle" refers to the second revolution of the crankshaft wheel 120. Traditionally, an index location is also utilized with the camshaft wheel 200. This includes an index tooth 205 and/or a gap where no teeth are located (analogous to the two-tooth gap in the crankshaft wheel 120). The camshaft wheel 200 teeth are numbered 0-N, where N is the number of cylinders for the engine (e.g., 0-6 for a six cylinder engine). In some embodiments, a camshaft sensor 210 may be utilized with the camshaft wheel 200 and to provide camshaft position data to the ECM 130.

[0031] Utilizing the 60-2 crankshaft wheel 120 configuration, each tooth in the plurality of teeth 122 corresponds to six degrees of rotation (360 degrees for one revolution = 60 teeth x 6 degrees/tooth). As mentioned above, the crankshaft wheel 120 makes two revolutions per revolution of the camshaft wheel 120. Thus, the crankshaft wheel rotates seven-hundred and twenty degrees per one revolution of the camshaft wheel 200. According, the 60-2 crankshaft wheel has a first revolution tooth count of 0-59 and a second revolution tooth count of 60-119 (includes the 0 for one-hundred and twenty teeth per two revolutions). However, as is better seen in FIG. 4, the camshaft wheel 200 tooth pattern is different for each crankshaft revolution (i.e., each half-cycle of the camshaft wheel 200). For example, crankshaft wheel 120 tooth number forty corresponds with a different crankshaft location and, in turn, camshaft position, based on if tooth number forty is encountered during the first revolution or the second revolution. In the first revolution, crankshaft wheel tooth forty is between camshaft wheel teeth one and two. In comparison, in the second revolution, tooth forty corresponds with tooth one -hundred, which is in between camshaft wheel teeth four and five. If the difference in position is not accounted for (i.e., determination of first half cycle or second half cycle), fuel may be injected into one or more cylinders not expecting fuel, which may lead to fuel build up and potential engine damage. As such, the position of the crankshaft must be synced with that of the camshaft prior to fuel being injected. By counting the teeth of the crankshaft wheel 120, the ECM 130 determines whether the camshaft wheel 120 is on the first half cycle or the second half cycle to therefore control the combustion events (e.g., which cylinders and when are injected with fuel).

[0032] Accordingly, the sensor 110 obtains and provides position data to the ECM 130 regarding the crankshaft wheel 120 position. For example, when embodied as a hall effect sensor, each time a crankshaft wheel tooth passes the sensor, the sensor detects a leading edge and a magnetic field is induced. The induced charge is converted by the sensor 110 to an "on" signal. The magnetic field disappears (no induction) during gaps between the teeth, which the sensor 110 converts to an "off signal. The "on" and "off signals are provided to the ECM 130 (i.e., position data).

[0033] Referring back to method 200, at process 203, the ECM 130 determines a first instance of engine oscillation based on the position data. Engine oscillation refers to the oscillation of the crankshaft wheel 120. During operation of the vehicle, the crankshaft wheel 120 rotates clockwise which corresponds with a forward movement of the vehicle (counterclockwise for reverse). However, while the engine is stopping, the engine (pistons/crankshaft) rotates forwards and backwards (oscillates). Thus, the crankshaft wheel 120 tooth count fluctuates during shut down.

[0034] Oscillation is detected by the occurrence of an unexpected signal gap from the sensor 110. For example, suppose the sensor 110 transmits four signals. The first signal ("no pulse") corresponds with the engine not spinning. The second signal ("no sync") corresponds with the engine spinning but the index location of the crankshaft wheel 120 has not been sensed. The third signal ("start sync") corresponds with the index location being sensed once and the fourth signal ("have sync") corresponds with the index location being sensed twice (i.e., the second revolution of the crankshaft wheel 120). After the stop command is received (process 201), the signal received by the ECM 130 is as follows: no sync - start sync - start sync - "gap" - no sync - no sync - no sync. The "gap" is an unexpected transmission in the signal (i.e., position data) thereby indicating that engine oscillation has occurred. The ECM 130 determines the position of the first instance of oscillation to be the crankshaft wheel 120 tooth that was last counted prior to the oscillation determination (process 203).

[0035] To further illustrate process 203, referring to FIG. 5, a graphical depiction of the crankshaft wheel position data showing an oscillation is depicted according to an example embodiment. As shown, through ten seconds of engine operation, the crank position tooth count is sinusoidal nature, fluctuating between a tooth count of zero and one-hundred and nineteen (start of first revolution to the second revolution of the crankshaft wheel). At position 501, the tooth count reaches approximately tooth number twenty-two and then descends rapidly back to zero rather than proceeding onward to toward tooth count one hundred and nineteen. The sudden change indicates an oscillation occurrence. Accordingly, in this example, the ECM 130 determines that the initial point of oscillation is at tooth number twenty-two of the crankshaft wheel 120 (process 203).

[0036] Based on the determined first instance of engine oscillation, the ECM estimates the engine stop position (process 204). Due to engine balancing, the engine comes to rest at repeatable, natural locations (i.e., stop locations). The natural engine stop locations may be shown in FIGS. 6-7. In FIG. 6, a graph of engine speed versus time for a plurality of restarts of a six-cylinder engine is shown according to an example embodiment. As shown, there are three distinct engine restart groups: group 610, group 620, and group 630. As an example, referring to group 610, the relative flat portion 605 beginning before 0.2 seconds and lasting to approximately 0.4 seconds is the dwell period. During this time frame, the starter motor is engaged with the engine and turning the crankshaft. At the end of this period, combustion is beginning to happen, where the combustion is responsible for the substantial increase in engine speed. Accordingly, the start of the dwell period is where the starter engages with the engine. As seen in FIG. 6, for each restart in the plurality of restarts, there are three locations where the starter motor engages with the crankshaft: 601, 602, and 603. These three locations correspond with the engine stop locations, where there is zero engine speed. The weighting and dynamics of the engine cause the engine to come to rest at the same repeatable locations (e.g. 601-603). This is why the starter motor repeatedly engages with the crankshaft at these locations. If there was not this type of balancing, the engine rotation may be off-balance, which may damage the engine block and/or cause the engine to vibrate away from the engine mounts in the vehicle. Accordingly, for the example six-cylinder engine case, FIG. 6 shows that there are three engine stop locations. To remain balanced, each stop location is substantially equally spaced apart with respect to the crankshaft wheel 120 (e.g., one -hundred and twenty degrees apart). In comparison, FIG. 7 shows that there are two engine stop locations for a four-cylinder engine: 701 and 702. In this case, each stop location is one- hundred and eighty degrees apart with respect to the crankshaft. As such, based on the engine, each engine has unique stop locations (three for a six-cylinder engine and two for a four-cylinder engine). These stop locations correspond with one revolution of the crankshaft wheel 120. Accordingly, for one revolution of the camshaft wheel 200, there are six total stop positions (for the six-cylinder case).

[0037] Referring to FIG. 8, FIG. 8 is a schematic diagram of combustible event locations and engine stop positions as a function of crankshaft wheel position according to an example embodiment. This schematic diagram is for a six-cylinder compression-ignition engine. Accordingly, in other embodiments (e.g., a four-cylinder spark-ignition engine), the location and number of the engine stop locations may differ. Moreover, as different crankshaft wheels may be utilized, the tooth number corresponding with an engine stop location or a "combustion at top dead center" (CTDC) location may also differ.

[0038] Referring back to process 204 in connection with FIG. 8, the ECM 130 estimates the engine stop location using the pre-calibrated engine stop locations (where the engine naturally comes to a rest, see, e.g., FIGS. 6-7) and the location where the first of oscillation was determined (process 204). For example, suppose the determined first instance of oscillation location was at tooth number five in FIG. 8. As the engine is shutting down, combustion has ceased. The crankshaft wheel 120 is lacking momentum to continue to rotate forward (increase in tooth count). Because the engine comes to a rest at predetermined locations (see FIGS. 6-7 and the description above), the ECM 130 determines that the engine stop position is at stop position #1. In another example, suppose the determined first instance of oscillation is at tooth number eighty-five. In this case, the ECM 130 determines that the engine stop position is at stop position #5. Thus, the estimated stop position is one of a plurality of crankshaft wheel stop positions based on weighting of the engine and the ECM 130 estimates the stop location to be the engine stop location immediately prior (i.e., preceding) to the location of the first instance of oscillation (based on the crankshaft wheel 120 tooth number). The ECM 130 stores the estimated stop position at process 205. The estimated stop position may be stored in one or more memory devices included with the ECM 130.

[0039] At process 206, the ECM 130 receives an engine restart command. The restart command includes a release of the brake pedal and a depression of the accelerator. In some embodiments, the restart command also includes a shift of gears (e.g., from neutral to first gear). In other words, the restart command initiates operation of the engine from the engine off position (with the ignition key in the on position). Upon reception of the restart command, the ECM 130 begins the engine restart process (process 207). The ECM 130 may provide one or more commands to one or more components of the engine system 100 to initiate the engine restart. The commands may include actuating a fuel injector, actuating the starter motor, actuating an ignition coil, actuating an intake air valve, and any other commands used in beginning combustion in the engine.

[0040] Based on the estimated engine stop position, the ECM provides an engine restart command to the next viable cylinder of the engine for sustainable combustion. Combustion requires a sufficient speed of the engine and for fuel to be injected at the proper location. For example, if the first instance of oscillation was at crankshaft wheel tooth number five, then the ECM 130 would estimate the stop position to be stop position #1 (see FIG. 8). The next combustion location is at CTDC#1. Although fuel may be injected at the proper location for CTDC#1, the approximately sixty-six degree stroke is like insufficient to cause sustainable combustion due to the lack of speed of the piston from the crankshaft rotation. From bottom dead center to top center, the crankshaft wheel rotation is one-hundred and eighty degrees. With each tooth corresponding to six degrees, there is an eleven tooth difference between stop position #1 one and CTDC#1, which equates to a sixty- six degree stroke (11 teeth x 6 degrees/tooth = 66 degrees). However, the next combustion location is at CTDC#2, approximately one-hundred and eighty degrees from stop position #1. As one-hundred and eighty degrees rotation of the crankshaft corresponds with the full stroke of a piston, the starter motor can provide enough power to the crankshaft to achieve sufficient speed. Thus, in this example, the next viable combustion location is CTDC#2. However, based on the ability of the starter motor to turn the crankshaft at a sufficient speed quickly, the next viable combustion location may be more or less than one-hundred and eighty degrees of rotation of the crankshaft. In other words, the next viable combustion location is at the first cylinder (i.e., CTDC#2) where the piston is at or near bottom dead center based on the estimated stop position. Because that piston is at bottom dead center, rotation of the crankshaft allows the piston to perform a full stroke from bottom dead center to top dead center to achieve the necessary speed for combustion in that cylinder. Accordingly, process 207 involves determination of the next viable combustion location (i.e., the next cylinder where the piston is at or near bottom dead center based on the estimated stop position) and then providing one or more commands to enable combustion at the next viable combustion. As mentioned above, these commands include actuation of a fuel injector for the appropriate cylinder, actuation of a starter motor to rotate the crankshaft, and actuation of one or more valves.

[0041] By remembering the estimated engine stop position (process 205) and providing commands for combustion at the next viable location (process 207), the ECM 130 avoids traditional engine synchronization. Accordingly, method 200 enables a relatively quicker engine restart.

[0042] As mentioned above, method 200 is utilized while the ignition is in the "on" position. In certain embodiments, during the first start of the engine, method 200 may be disabled because engine stop location information is not yet known. However, when the ignition is "on," although the engine has turned off, power to ECM 130 is still provided such that the engine stop location is stored for fast restart of the engine. In an alternate embodiment, the ECM 130 may store engine stop location information even after the ignition is turned "off," to enable a relatively faster initial start-up of the engine. A dedicated power source may be utilized with the ECM 130 to power one or more memory devices to store the engine stop location.

[0043] As mentioned above the method and Figures described herein were in regard to a compression-ignition engine. However, the same method may be utilized with a spark- ignition engine. In this embodiment, the ECM 130 would control power to the ignition coil to provide a spark and cause combustion (as compared to when and to what cylinder fuel is injected into in the compression-ignition case). It should be noted that the term "example" as used herein to describe various embodiments is intended to indicate that such embodiments are possible examples, representations, and/or illustrations of possible embodiments (and such term is not intended to connote that such embodiments are necessarily extraordinary or superlative examples).

[0044] The present disclosure contemplates methods, systems, and program products on any machine-readable media for accomplishing various operations. As mentioned above, in certain embodiments, the ECM forms a processing system or subsystem that includes one or more computing devices having memory, processing, and communication hardware. The ECM may be a single device or a distributed device, and the functions of the processor may be performed by hardware and/or as computer instructions on a non- transient computer (or machine) readable storage medium. Such computer-readable media can be any available media that can be accessed by a general purpose or special purpose computer or other machine with a processor. By way of example, such computer-readable media can comprise RAM, ROM, EPROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to carry or store desired program code in the form of machine- executable instructions or data structures and which can be accessed by a general purpose or special purpose computer or other machine with a processor. In certain embodiments, the ECM includes one or more modules structured to functionally execute the operations described herein. The description herein including the components of the ECM emphasizes the structural independence of the aspects of the ECM, and illustrates one grouping of operations and responsibilities of the ECM. Other groupings that execute similar overall operations are understood within the scope of the present application. Modules may be implemented in hardware and/or as computer instructions on a non-transient computer readable storage medium, and modules may be distributed across various hardware or computer based components.

[0045] Example and non-limiting module implementation elements include sensor (e.g., sensors 110) providing any value determined herein, sensors providing any value that is a precursor to a value determined herein, datalink and/or network hardware including communication chips, oscillating crystals, communication links, cables, twisted pair wiring, coaxial wiring, shielded wiring, transmitters, receivers, and/or transceivers, logic circuits, hard- wired logic circuits, reconfigurable logic circuits in a particular non-transient state configured according to the module specification, any actuator including at least an electrical, hydraulic, or pneumatic actuator, a solenoid, an op-amp, analog control elements (springs, filters, integrators, adders, dividers, gain elements), and/or digital control elements.