Engine stop/start inhibit during vehicle service

Systems and methods for operating an engine that may be automatically stopped and started without a human driver providing input to a device that has a sole function of stopping and starting the engine are presented. In one example, automatic engine starting is inhibited responsive to output of vehicle sensors that may be indicative of service being performed on a vehicle.

FIELD

The present description relates to a system and methods for inhibiting automatic engine starting when vehicle service is being performed after an engine has been automatically stopped. The methods and system may assist a vehicle operator that has neglected to deactivate a vehicle before initiating service of the vehicle.

BACKGROUND AND SUMMARY

A vehicle may include an engine that may be automatically stopped and started without a human driver providing input to a device (e.g., key switch or pushbutton) that has a sole function of stopping and starting the engine. The engine may be automatically stopped to conserve fuel, and then, the engine may be automatically restarted to propel the vehicle or to charge a battery. The engine may be automatically stopped while the transmission that is coupled to the transmission is engaged in a gear or in park. Some drivers may absent mindedly leave the vehicle while the vehicle is activated after the engine is automatically stopped. If the vehicle's battery discharges to a lower level while the vehicle is activated, the engine may be automatically started to charge the battery. However, the engine may also be automatically started when maintenance is being performed on the vehicle after the vehicle's driver has exited the vehicle and after the engine has been automatically stopped. The person performing the maintenance on the vehicle may be startled if the engine automatically restarts. Thus, automatically restarting the engine when maintenance is being performed on the vehicle may be undesirable.

The inventors herein have recognized the above-mentioned limitations and have developed an engine control method, comprising: automatically stopping an engine responsive to vehicle operating conditions; and inhibiting automatic starting of the engine in response to an indication that service is being performed on a vehicle while the vehicle's engine compartment hood is closed.

By inhibiting automatic engine restarting after an automatic engine stop in response to an indication that maintenance is being performed on a vehicle, it may be possible to provide the technical result of preventing automatic engine starting when maintenance is being performed on a vehicle. Further, the automatic engine starting may be prevented when the maintenance performed on the vehicle is not under hood maintenance so that the engine does not suddenly start when the vehicle is elevated for service, for example. In one example, automatic engine restarting may be prevented based on a tire pressure change or a change in vehicle suspension height. The inhibiting of automatic engine restarting may be enforced up to a time when an engine start is specifically requested via a human driver.

The present description may provide several advantages. In particular, the approach may reduce the possibility of unwanted engine starts. In addition, the approach may increase owner or driver satisfaction by operating the vehicle in a way that may be preferred by the driver. Further, the approach may be implemented via a variety of different sensors such that it may be implemented at low or no additional vehicle cost.

DETAILED DESCRIPTION

The present description is related to improving engine operation and vehicle operation during conditions after an engine has been automatically stopped. An engine of the type described inFIG. 1may be automatically stopped and started to conserve fuel and reduce engine emissions. The engine may be included in a vehicle driveline as shown inFIG. 2. The driveline may be part of a vehicle that includes various sensors as shown inFIGS. 3A-3C. The engine and vehicle may be operated according to the method ofFIG. 4. The engine and vehicle may operate according to the sequence ofFIG. 5.

Referring toFIG. 1, internal combustion engine10, comprising a plurality of cylinders, one cylinder of which is shown inFIG. 1, is controlled by electronic engine controller12. Engine10includes combustion chamber30and cylinder walls32with piston36positioned therein and connected to crankshaft40. Combustion chamber30is shown communicating with intake manifold44and exhaust manifold48via respective intake valve52and exhaust valve54. Each intake and exhaust valve may be operated by an intake cam51and an exhaust cam53. The position of intake cam51may be determined by intake cam sensor55. The position of exhaust cam53may be determined by exhaust cam sensor57. Intake cam51and exhaust cam53may be moved relative to crankshaft40. Intake valves may be deactivated and held in a closed state via intake valve deactivating mechanism59. Exhaust valves may be deactivated and held in a closed state via exhaust valve deactivating mechanism58.

Fuel injector66is shown positioned to inject fuel directly into cylinder30, which is known to those skilled in the art as direct injection. Alternatively, fuel may be injected to an intake port, which is known to those skilled in the art as port injection. Fuel injector66delivers liquid fuel in proportion to the pulse width of signal from controller12. Fuel is delivered to fuel injector66by a fuel system175, which includes a tank and pump. In addition, intake manifold44is shown communicating with optional electronic throttle62(e.g., a butterfly valve) which adjusts a position of throttle plate64to control air flow from air filter43and air intake42to intake manifold44. Throttle62regulates air flow from air filter43in engine air intake42to intake manifold44. In some examples, throttle62and throttle plate64may be positioned between intake valve52and intake manifold44such that throttle62is a port throttle.

Engine10may be rotated (e.g., cranked) via starter95during engine starting. Fuel and spark may be provided to engine10while starter95rotates engine10. Combustion in engine10may accelerate engine10above a speed of starter95so that starter95decouples from crankshaft40after engine10starts.

Controller12is shown inFIG. 1as a conventional microcomputer including: microprocessor unit102, input/output ports104, read-only memory106(e.g., non-transitory memory), random access memory108, keep alive memory110, and a conventional data bus. Controller12is shown receiving various signals from sensors coupled to engine10, in addition to those signals previously discussed, including: engine coolant temperature (ECT) from temperature sensor112coupled to cooling sleeve114; a position sensor134coupled to an accelerator pedal130for sensing force applied by human driver132; a measurement of engine manifold pressure (MAP) from pressure sensor122coupled to intake manifold44; an engine position sensor from a Hall effect sensor118sensing crankshaft40position; a measurement of air mass entering the engine from sensor120; brake pedal position from brake pedal position sensor154when human driver132applies brake pedal150; a level of oil41in engine10via oil level sensor39; and a measurement of throttle position from sensor58. Barometric pressure may also be sensed (sensor not shown) for processing by controller12. In a preferred aspect of the present description, engine position sensor118produces a predetermined number of equally spaced pulses every revolution of the crankshaft from which engine speed (RPM) can be determined. Controller12may receive input from human/machine interface115(e.g., pushbutton or touch screen display). Controller12may start engine10in response to input to device116(e.g., key switch or pushbutton), which has a dedicated function of requesting engine starting and stopping via a human driver.

In some examples, the engine may be coupled to an electric motor/battery system in a hybrid vehicle. Further, in some examples, other engine configurations may be employed, for example a diesel engine.

Referring now toFIG. 2, a block diagram of a vehicle225including a powertrain or driveline200is shown. The powertrain ofFIG. 2includes engine10shown inFIG. 1. Powertrain200is shown including vehicle system controller255, engine controller12, transmission controller254, and brake controller250. The controllers may communicate over controller area network (CAN)299. Each of the controllers may provide information to other controllers such as torque output limits (e.g., torque output of the device or component being controlled not to be exceeded), torque input limits (e.g., torque input of the device or component being controlled not to be exceeded), torque output of the device being controlled, sensor and actuator data, diagnostic information (e.g., information regarding a degraded transmission, information regarding a degraded engine, information regarding a degraded electric machine, information regarding degraded brakes). Further, the vehicle system controller255may provide commands to engine controller12, transmission controller254, and brake controller250to achieve driver input requests and other requests that are based on vehicle operating conditions.

In other examples, the partitioning of controlling powertrain devices may be partitioned differently than is shown inFIG. 2. For example, a single controller may take the place of vehicle system controller255, engine controller12, transmission controller254, and brake controller250. Alternatively, the vehicle system controller255and the engine controller12may be a single unit while the transmission controller254, and the brake controller250are standalone controllers.

In this example, powertrain200may be powered by engine10. Further, torque of engine10may be adjusted via torque actuator204, such as a fuel injector, throttle, etc. Engine10receives fuel via fuel injectors66, fuel rail239, and fuel tank209. Fuel pressure in fuel rail239may be sensed via fuel pressure sensor238. An engine output torque may be transmitted to impeller285. Torque converter206includes a turbine286to output torque to input shaft270. Input shaft270mechanically couples torque converter206to automatic transmission208. Torque converter206also includes a torque converter bypass lock-up clutch212(TCC). Torque is directly transferred from impeller285to turbine286when TCC is locked. TCC is electrically operated by controller12. Alternatively, TCC may be hydraulically locked. In one example, the torque converter may be referred to as a component of the transmission.

When torque converter lock-up clutch212is fully disengaged, torque converter206transmits engine torque to automatic transmission208via fluid transfer between the torque converter turbine286and torque converter impeller285, thereby enabling torque multiplication. In contrast, when torque converter lock-up clutch212is fully engaged, the engine output torque is directly transferred via the torque converter clutch to an input shaft270of transmission208. Alternatively, the torque converter lock-up clutch212may be partially engaged, thereby enabling the amount of torque directly relayed to the transmission to be adjusted. The transmission controller254may be configured to adjust the amount of torque transmitted by torque converter212by adjusting the torque converter lock-up clutch in response to various engine operating conditions, or based on a driver-based engine operation request.

Automatic transmission208includes gear clutches (e.g., gears1-10)211and forward clutch210for activating gears213(e.g., gears1-10). Automatic transmission208is a fixed ratio transmission that may operate according to a position of shifter221. Shifter221may assume one or positions of park (P), reverse (R), neutral (N), drive (D), or low (low). The gear clutches211and the forward clutch210may be selectively engaged to change a ratio of an actual total number of turns of input shaft270to an actual total number of turns of wheels216. Gear clutches211may be engaged or disengaged via adjusting fluid supplied to the clutches via shift control solenoid valves209. Torque output from the automatic transmission208may also be relayed to wheels216to propel the vehicle via output shaft260. Specifically, automatic transmission208may transfer an input driving torque at the input shaft270responsive to a vehicle traveling condition before transmitting an output driving torque to the wheels216. Transmission controller254selectively activates or engages TCC212, gear clutches211, and forward clutch210. Transmission controller also selectively deactivates or disengages TCC212, gear clutches211, and forward clutch210.

Further, a frictional force may be applied to wheels216by engaging friction wheel brakes218. In one example, friction wheel brakes218may be engaged in response to the driver pressing his foot on a brake pedal (not shown) and/or in response to instructions within brake controller250. Further, brake controller250may apply brakes218in response to information and/or requests made by vehicle system controller255. In the same way, a frictional force may be reduced to wheels216by disengaging wheel brakes218in response to the driver releasing his foot from a brake pedal, brake controller instructions, and/or vehicle system controller instructions and/or information. For example, vehicle brakes may apply a frictional force to wheels216via controller250as part of an automated engine stopping procedure.

In response to a request to accelerate vehicle225, vehicle system controller may obtain a driver demand torque or power request from an accelerator pedal or other device. Vehicle system controller255then allocates the requested driver demand torque to the engine. Vehicle system controller255requests the engine torque from engine controller12. If engine torque is less than a transmission input torque limit (e.g., a threshold value not to be exceeded), the torque is delivered to torque converter206which then relays at least a fraction of the requested torque to transmission input shaft270. Transmission controller254selectively locks torque converter clutch212and engages gears via gear clutches211in response to shift schedules and TCC lockup schedules that may be based on input shaft torque and vehicle speed.

Accordingly, torque control of the various powertrain components may be supervised by vehicle system controller255with local torque control for the engine10, transmission208, and brakes218provided via engine controller12, transmission controller254, and brake controller250.

As one example, an engine torque output may be controlled and/or limited by adjusting a combination of spark timing, fuel pulse width, fuel pulse timing, and/or air charge, by controlling throttle opening and/or valve timing, valve lift and boost for turbo- or super-charged engines. In the case of a diesel engine, controller12may control the engine torque output by controlling a combination of fuel pulse width, fuel pulse timing, and air charge. In all cases, engine control may be performed on a cylinder-by-cylinder basis to control the engine torque output.

Transmission controller254receives transmission input shaft position via position sensor271. Transmission controller254may convert transmission input shaft position into input shaft speed via differentiating a signal from position sensor271or counting a number of known angular distance pulses over a predetermined time interval. Transmission controller254may receive transmission output shaft torque from torque sensor272. Alternatively, sensor272may be a position sensor or torque and position sensors. If sensor272is a position sensor, controller254may count shaft position pulses over a predetermined time interval to determine transmission output shaft velocity. Transmission controller254may also differentiate transmission output shaft velocity to determine transmission output shaft acceleration. Transmission controller254, engine controller12, and vehicle system controller255, may also receive addition transmission information from sensors277, which may include but are not limited to vehicle situational awareness sensors (e.g., cameras, microphones, and range detecting systems including radar, laser, and sonic transmitting and sensing devices), transmission hydraulic pressure sensors (e.g., gear clutch fluid pressure sensors), tire pressure sensors, suspension height sensors, inertial sensors (e.g., accelerometers, yaw, pitch, and roll sensors), and ambient temperature sensors.

Brake controller250receives wheel speed information via wheel speed sensor221and braking requests from vehicle system controller255. Brake controller250may also receive brake pedal position information from brake pedal sensor154shown inFIG. 1directly or over CAN299. Brake controller250may provide braking responsive to a wheel torque command from vehicle system controller255. Brake controller250may also provide anti-skid and vehicle stability braking to improve vehicle braking and stability.

Referring now toFIG. 3A, an example vehicle225in which engine10may reside is shown. Directions relative to vehicle225are indicated via longitudinal, vertical, and transverse directional arrows. Vehicle225includes a 360 degree camera349that may sense movement within a threshold distance of vehicle225, and 360 degree camera349may have a 360 degree field of view around vehicle225. Each vehicle tire312may include a pressure sensor306for informing vehicle controller (e.g.,255shown inFIG. 2) of pressure in tires312. Vehicle225also includes an engine compartment hood325that at least partially covers engine compartment326. Engine compartment hood325is shown in a closed position. Engine compartment326houses engine10shown inFIG. 1.

From time to time, vehicle elevating device or jack350may be used to elevate vehicle225for service. For example, jack350may be placed near a wheel so that vehicle225may be elevated near the wheel so that tire312may be rotated or serviced. Further, jack350may be used to elevate vehicle225for servicing brakes, fuel filters, and performing oil changes. When jack350elevates one wheel, pressure in the tire that is attached to the wheel may be reduced since external load on the tire has been reduced or removed. Further, when one wheel is elevated, pressures in the other vehicle tires may increase due to additional external load being applied to the tires that remain in contact with the ground.

FIG. 3Bshows an example chassis suspension320for vehicle225or a similar vehicle. Directions relative to vehicle225and suspension320are indicated via longitudinal, vertical, and transverse directional arrows. Tire312is mounted to a wheel (not shown) and the wheel is mounted to hub308. Hub308is mechanically coupled to lower control arm319and upper control arm320. Upper control arm320and lower control arm319may pivot about chassis support321, which may be part of the vehicle's body. Spring315is coupled to chassis support321and lower control arm319such that spring315supports chassis support321. Hub308, upper control arm320, and lower control arm319are unsprung since they are not supported by spring315and they move according to a surface of the road the vehicle is traveling on. A damper (not shown) may accompany spring315to provide a second order system. Vehicle suspension vertical height sensor359outputs an indication of the height of suspension320and vehicle225relative to ground399. Tire pressure sensor306may transmit a signal representative of tire pressure to vehicle system controller255or a receiver310that may be electrically coupled to vehicle system controller255.

FIG. 3Cshows another example vehicle chassis suspension350for vehicle225or a similar vehicle. Tire312is mounted to a wheel (not shown) and the wheel is mounted to hub357. Hub357is mechanically coupled to axle361. Spring351is coupled to chassis355and axle361. Hub308and axle361are unsprung since they are not supported by spring351and they move according to a surface of the road the vehicle is traveling on. A damper (not shown) may accompany spring351to provide a second order system. Vehicle suspension vertical height sensor359outputs an indication of the height of suspension350and vehicle225relative to ground399.

The system ofFIGS. 1-3Cprovides for a vehicle system, comprising: an engine coupled to a vehicle; and a controller including executable instructions stored in non-transitory memory to automatically stop the engine responsive to vehicle operating conditions and inhibit automatically starting the engine responsive to an indication of service being performed on the vehicle provided via a vehicle suspension sensor. The system further comprises additional executable instructions stored in non-transitory memory to inhibit automatically starting the engine responsive to an indication of service being performed on the vehicle provided via a fuel rail pressure sensor. The system further comprises additional executable instructions stored in non-transitory memory to inhibit automatically starting the engine responsive to an indication of service being performed on the vehicle provided via an oil level sensor. The system further comprises additional executable instructions stored in non-transitory memory to inhibit automatically starting the engine responsive to an indication of service being performed on the vehicle provided via a camera. The system further comprises additional executable instructions stored in non-transitory memory to inhibit automatically starting the engine responsive to an indication of service being performed on the vehicle provided via inertial sensors. The system further comprising additional executable instructions stored in non-transitory memory to inhibit automatically starting the engine responsive to an indication of service being performed on the vehicle provided via a tire pressure sensor.

Referring now toFIG. 4, an example flow chart of method400for operating an engine and vehicle is shown. The method ofFIG. 4may be incorporated into and may cooperate with the system ofFIGS. 1-3C. Further, at least portions of the method ofFIG. 4may be incorporated as executable instructions stored in non-transitory memory while other portions of method400may be performed via a controller transforming operating states of devices and actuators in the physical world.

At402, method400judges if the vehicle is activated. The vehicle may be activated via a human applying a pushbutton, key switch, or a signal transmitted via a remote device (e.g., a key fob or a phone). Activating the vehicle may comprise pressurizing fuel to a fuel rail and performing other actions to ready the vehicle for travel. Method400may judge that the vehicle is activated based on status of a variable that is stored in controller memory. If method400judges that the vehicle is activated, the answer is yes and method400proceeds to404. Otherwise, the answer is no and method400proceeds to450.

At450, method400deactivates the vehicle's propulsion sources. The engine may be deactivated by ceasing to supply spark and fuel to the engine. Further, additional actions may be taken to deactivate the engine. For example, electrical power may be withheld from the engine's controller and engine sensors and actuators. For vehicles that include electric machines for propulsion, electrical power may be withdrawn from the electric machines. Method400proceeds to exit after deactivating vehicle propulsion sources.

At404, method400optionally judges if the vehicle's transmission shifter and the transmission is engaged in park. The shifter may output its position to the transmission or vehicle controller to indicate the transmission's operating state. If method400judges that the transmission is engaged in park, the answer is yes and method400proceeds to406. Otherwise, the answer is no and method400proceeds to452. If step404is omitted, method400proceeds to406.

At406, method400judges if engine stop/start control is activated and the engine has been automatically stopped (e.g., the engine has been stopped via the controller without a human driver specifically requesting an engine stop via a dedicated input that has a sole function of requesting stopping and starting of the engine). Method400may query a variable in controller memory to determine if engine stop/start control is activated, and method400may also query a second variable in memory to determine if the engine has been automatically stopped. The status of these variables may be changed and controlled via the engine controller or the vehicle system controller. Alternatively, method400may determine engine stop/start control status and engine operating status via operating states of sensors and actuators. If method400judges that engine stop/start control is activated and that the engine has been automatically stopped, the answer is yes and method400proceeds to408. Otherwise, the answer is no and method400proceeds to452.

At452, method400operates the engine responsive to vehicle operating conditions. For example, the engine may be started and run (e.g., rotating the engine's crankshaft and combusting fuel) responsive to driver demand torque. The driver demand torque may be determined via accelerator pedal position and vehicle speed. Further, the engine may be automatically stopped in response to driver demand torque less than a threshold and vehicle speed being less than a threshold. Method400proceeds to exit.

At408, method400monitors pressures of each vehicle tired via a plurality of tire pressure sensors. Tire pressure changes may be indicative of service being performed on a vehicle. In particular, if a vehicle is lifted off of the ground via a hoist, air pressure in each of the vehicle's tires may decrease within a predetermined amount of time since the vehicle was lifted off of the ground. The change in all tire pressures may be indicative of the vehicle being lifted via a hoist and the vehicle being service. Thus, if all tire pressures change by a threshold amount of pressure in a predetermined amount of time, then it may be inferred by a controller that the vehicle is undergoing service and/or being lifted.

During some conditions, pressure in one tire of a vehicle may decrease and pressures in one or more other tires of the vehicle may increase. Such conditions may be indicative of a vehicle being lifted via a jack (e.g., a portable vehicle lifting device) at one of the vehicle's wheels. Thus, if pressure in one tire decreases and pressure in one or more tires increase within a threshold amount of time, it may be inferred by a controller that the vehicle is being lifted for service (e.g., a tire change or rotate). Tire sensors may report tire pressures to one or more controllers at predetermined time intervals. A record of tire pressures over a predetermined amount of time may be stored in controller random access memory so that rates of tire pressure change may be determined over a predetermined amount of time.

Additionally, it may be inferred that a vehicle is being serviced if a location of a tire pressure sensor changes or if the signal of the tire pressure sensor is no longer observable. For example, if a front left tire pressure is 240 kilopascals and a rear tire pressure is 210 kilopacals at a first time, and then, the a front left tire pressure changes to 210 kilopascals and a rear tire pressure changes to 240 kilopacals at a second time, it may be inferred that the tire positions have change and that the vehicle is being serviced. Method400proceeds to410after monitoring tire pressures.

At410, monitors vehicle suspension vertical height sensor output. The vertical height sensor output may be indicative of vehicle suspension vertical height relative to a base position and vehicle chassis vertical height with respect to ground (e.g., earth). Vehicle chassis vertical height changes may be indicative of service being performed on a vehicle. In particular, if a vehicle is lifted off of the ground via a hoist, vertical height of the suspension and chassis may increase at each of the vehicle's wheels since the vehicle was lifted off of the ground, thereby reducing normal force that is applied to the suspension. The change in chassis and suspension vertical height may be indicative of the vehicle being lifted via a hoist and the vehicle being serviced. Thus, if vertical heights of all suspension components and/or chassis corners change by a threshold amount of distance in a predetermined amount of time, then it may be inferred by a controller that the vehicle is undergoing service and being lifted.

During some conditions, the vertical height of one suspension linkage or chassis corner of a vehicle may increase and vertical height of one or more other suspension linkages may decrease. Such conditions may be indicative of a vehicle being lifted via a jack at one of the vehicle's wheels. Thus, if vehicle suspension or chassis vertical height increases at one wheel and decreases at one or more other wheels within a threshold amount of time, it may be inferred by a controller that the vehicle is being lifted for service (e.g., brake replacement, oil change, etc.). Vehicle vertical height sensors may report suspension height and vehicle chassis height changes to one or more controllers at predetermined time intervals. A record of suspension and chassis vertical height changes over a predetermined amount of time may be stored in controller random access memory so that rates of change in chassis vertical height and suspension vertical height may be determined over a predetermined amount of time. Method400proceeds to412after monitoring vehicle suspension heights.

At412, method400monitors output of vehicle cameras to determine if there is movement by persons within a predetermined distance of the vehicle (e.g., 1 meter). Camera images may be processed to determine if objects in the images are moving. If objects in the images are determined to be moving and if the objects are within a predetermined distance of the vehicle, it may be inferred that service is being performed on the vehicle (e.g., cleaning, changing windshield wipers, etc.). Method400proceeds to414after monitoring output of vehicle cameras.

At414, method400monitors output of fuel pressure and engine oil level sensors. A change in fuel pressure (e.g., a reduction in fuel pressure) that is greater than a threshold amount in a threshold amount of time may be indicative that a fuel filter is being changed. In particular, releasing a fuel filter from a fuel line may reduce pressure in a fuel rail. The reduction in fuel rail pressure may be indicative of service that is being performed on a vehicle. The fuel filter may be located under the chassis of the vehicle so that the vehicle's hood is not opened to change the fuel filter, yet the change in fuel pressure may be indicative of service being performed on the vehicle.

Output of an oil level sensor may be monitored to determine that a vehicle's engine oil is being changed. In particular, a drain plug of an engine's oil pan may be removed so that the engine's oil level may be reduced in a short period of time. If the engine oil level changes (e.g., is reduced) by more than a threshold amount in a threshold amount of time, it may be inferred that service is being performed on the vehicle even though the vehicle's hood is not open. Method400proceeds to416after monitoring fuel rail pressure and oil level sensor output.

At416, method400monitors output of inertial sensors (e.g., yaw, pitch, roll sensors). A change in vehicle position that is greater than a threshold amount in less than a threshold amount of time may be indicative of service being performed on a vehicle. A vehicle's inertial sensor output may change and indicate a change in vehicle position. The change in vehicle position may indicate that the vehicle is being lifted. Method400proceeds to418after monitoring output of the vehicle's inertial sensors.

At418, method400judges if any of the monitored sensors provide an indication of activity about or under the vehicle. Further, method400may judge if any of the monitored sensors provide an indication that the vehicle is being serviced. If one or more of the vehicle sensors indicate activity about or under the vehicle, or if one or more of the vehicle sensors indicate that the vehicle may be in the process of being serviced, the answer is yes and method400proceeds to420. Otherwise, the answer is no and method400returns to402.

At420, method400inhibits automatic engine starting in response to the sensors indicating activity about the vehicle or the vehicle being serviced. Automatic engine starting may be inhibited by not allowing the starter to rotate the engine. Further, delivery of spark and fuel to the engine may be prevented by holding fuel injectors in a closed state and preventing ignition coils from charging. Automatic engine starting may be inhibited from a time when the sensors indicate activity about the vehicle or that the vehicle is being serviced to a time when a human driver requests an engine start via a dedicated engine starting/stopping input (e.g., a key switch or a pushbutton) or overrides the inhibiting of automatic starting. Method400proceeds to422.

At422, method400indicates that the vehicle is in stop/start mode and that automatic engine starting is inhibited. Method400may provide a visual indication of the vehicle operating state via a human/machine interface. Additionally, or optionally, method400may provide an audible indication of the vehicle's operating mode via an infotainment system or other device. Method400proceeds to exit.

In this way, vehicle sensors may indicate that a vehicle is being serviced or that there is activity about the vehicle even when the vehicle's engine compartment hood is closed. The vehicle sensor output may be used to infer that service is being performed on the vehicle at a time when the engine has been automatically stopped. The inference may then be the basis for inhibiting automatic engine starting.

Thus, the method ofFIG. 4provides for an engine control method, comprising: automatically stopping an engine responsive to vehicle operating conditions; and inhibiting automatic starting of the engine in response to an indication that service is being performed on a vehicle while the vehicle's engine compartment hood is closed. The method further comprises monitoring vehicle suspension sensors for the indication that service is being performed on the vehicle. The method further comprises monitoring tire pressure sensors for the indication that service is being performed on the vehicle. The method further comprises monitoring a camera for the indication that service is being performed on the vehicle. The method further comprises monitoring fluid level sensors for the indication that service is being performed on the vehicle. The method further comprises monitoring pressure sensors for the indication that service is being performed on the vehicle. The method further comprises inertial sensors for the indication that service is being performed on the vehicle.

The method ofFIG. 4also provides for an engine control method, comprising: automatically stopping an engine responsive to vehicle operating conditions; inhibiting automatic starting of the engine in response to an indication that service is being performed on a vehicle while the vehicle's engine compartment hood is closed, where inhibiting automatic starting of the engine includes inhibiting automatic starting of the engine to a time when the inhibiting is overridden via a human. The method includes where inhibiting automatic starting of the engine includes not supplying fuel to the engine. The method includes where inhibiting automatic starting of the engine includes not cranking the engine via a starter. The method includes where the indication that service is being performed is a change in an engine oil level. The method includes where the indication that service is being performed is a change in fuel pressure. The method includes where the indication that service is being performed is a change in tire pressure. The method includes where the indication that service is being performed is provided via a camera.

In another representation, the method ofFIG. 4provides for an engine control method, comprising: automatically stopping an engine responsive to vehicle operating conditions, inhibiting automatic starting of the engine in response to an indication that engine oil is being changed, the indication that engine oil is being changed based on output of an engine oil level sensor. The method includes where the indication may be provided when the vehicle's engine compartment hood is closed. The method includes inhibiting automatic engine starting up to a time when the inhibiting is overridden via a human. The method further comprises automatically inhibiting the starting of the engine in response to a change in fuel pressure exceeding a threshold amount in less than a predetermined amount of time.

Referring now toFIG. 5, an example vehicle operating sequence is shown. The sequence shown inFIG. 5may be provided via the system ofFIGS. 1-3Cin cooperation with the method ofFIG. 4. The vertical lines indicate times of interest in the sequence. The plots are aligned in time.

The first plot from the top ofFIG. 5is a plot of the vehicle operating status versus time. The vertical axis represents the vehicle operating status. The horizontal axis represents time and time increases from the left side of the figure to the right side of the figure. Trace502represents vehicle operating state. The vehicle is activated when trace502is at a higher level near the vertical axis arrow. The vehicle is deactivated when trace502is at a lower level near the horizontal axis.

The second plot from the top ofFIG. 5is a plot of the engine stop/start mode operating status versus time. The vertical axis represents the engine stop/start mode operating status. The horizontal axis represents time and time increases from the left side of the figure to the right side of the figure. Trace504represents engine stop/start mode operating state. The engine stop/start mode is activated when trace504is at a higher level near the vertical axis arrow. The engine stop/start mode is deactivated when trace504is at a lower level near the horizontal axis.

The third plot from the top ofFIG. 5is a plot of output of a first vehicle suspension vertical height sensor versus time. The vertical axis represents the first vehicle suspension vertical height. The horizontal axis represents time and time increases from the left side of the figure to the right side of the figure. Trace506represents a first vehicle suspension vertical height. The first vehicle suspension vertical height increases in the direction of the vertical axis arrow.

The fourth plot from the top ofFIG. 5is a plot of output of a second vehicle suspension vertical height sensor versus time. The vertical axis represents the second vehicle suspension vertical height. The horizontal axis represents time and time increases from the left side of the figure to the right side of the figure. Trace508represents a second vehicle suspension vertical height. The second vehicle suspension vertical height increases in the direction of the vertical axis arrow.

The fifth plot from the top ofFIG. 5is a plot of state of inhibiting of automatic engine starting versus time. The vertical axis represents the state of inhibiting of automatic engine starting operating status. The horizontal axis represents time and time increases from the left side of the figure to the right side of the figure. Trace510represents a state of inhibiting of automatic engine starting vehicle operating state. Inhibiting of automatic engine start is activated when trace510is at a higher level near the vertical axis arrow. Inhibiting of automatic engine start is deactivated when trace510is at a lower level near the horizontal axis (e.g., the engine may be automatically started).

At time t0, the vehicle is activated and the engine (not shown) is running. The engine stop/start mode is not activated and the first vehicle height sensor output is at a middle level. The output of the second vehicle height sensor output is at a same level as the first vehicle height sensor output. Inhibiting of automatic starting is not active.

At time t1, the engine stop/start mode is activated and the engine is automatically stopped (e.g., fuel and spark delivery to the engine ceases and the engine crankshaft ceases rotating) in response to the engine stop/start mode being activated. The output of the first and second vehicle height sensors is unchanged and the vehicle remains activated. Inhibiting of automatic engine start is not activated.

At time t2, the vehicle remains activated and the engine stop/start mode remains activated. The output of the first and second vehicle height sensors begin to change in response to one wheel of the vehicle being elevated (not shown) and inhibiting of automatic engine starting is not activated.

At time t3, the output of the first vehicle suspension vertical height sensor ceases changing and it has increased to indicate that the vertical height of the vehicle has increased at the location of the first vehicle suspension vertical height sensor. The output of the second vehicle suspension vertical height sensor ceases changing and it has decreased to indicate that the vertical height of the vehicle has decreased at the location of the second vehicle suspension vertical height sensor. The combined changes of the first and second vehicle suspension vertical height sensor outputs indicates that one vehicle suspension element is elevated and another vehicle suspension element is compressed, which may indicate that the vehicle is being jacked up on one side. Inhibiting of automatic engine starting is not activated and the vehicle remains activated. The engine stop/start mode remains engaged and the engine remains stopped (not shown).

At time t4, inhibiting of automatic engine starting is asserted so that the engine may not be automatically started in response to the change in the output of the first and second vehicle suspension vertical height sensors between time t2and time t3. The vehicle remains in an activated state and the engine stop/start mode remains activated; however, in some examples, the engine stop/start mode may be deactivated in response to inhibiting of automatic engine starting. The output of the first and second vehicle vertical height sensors remains unchanged.

Thus, output of the vehicle suspension vertical height sensors may be a basis for determining if service may be in the process of being performed. Further, automatic engine starting may be inhibited based on the output of the vehicle suspension vertical height sensors. Similarly, outputs of the other sensors described herein may also be the basis for determining whether or not a vehicle may be in the process of being serviced.

Note that the example control and estimation routines included herein can be used with various engine and/or vehicle system configurations. Further, the routines may be repeatedly performed. The control methods and routines disclosed herein may be stored as executable instructions in non-transitory memory and may be carried out by the control system including the controller in combination with the various sensors, actuators, and other engine hardware. The specific routines described herein may represent one or more of any number of processing strategies such as event-driven, interrupt-driven, multi-tasking, multi-threading, and the like. As such, various actions, operations, and/or functions illustrated may be performed in the sequence illustrated, in parallel, or in some cases omitted. Likewise, the order of processing is not necessarily required to achieve the features and advantages of the example embodiments described herein, but is provided for ease of illustration and description. One or more of the illustrated actions, operations and/or functions may be repeatedly performed depending on the particular strategy being used. Further, at least a portion of the described actions, operations and/or functions may graphically represent code to be programmed into non-transitory memory of the computer readable storage medium in the control system. The control actions may also transform the operating state of one or more sensors or actuators in the physical world when the described actions are carried out by executing the instructions in a system including the various engine hardware components in combination with one or more controllers.