Predictive startup and shutdown of an internal combustion engine in a hybrid vehicle

Abstract

A method of controlling a hybrid vehicle (10, 126) having an internal combustion engine (14) configured to automatically stop in response to an internal combustion engine stop request and to automatically start in response to an internal combustion engine start request, the method comprising: Inhibiting an engine stop request based on the expected duration of an expected driver-commanded reduced power condition to reduce the occurrence of consecutive automatic stops and automatic starts; and Delaying a downshift or upshift of a vehicle transmission (16) in response to the expected duration of the expected driver-commanded reduced power condition.

Description

TECHNICAL FIELDThe disclosure relates to hybrid vehicles having engine stop-and-start logic and modification of the stop-and-start logic in response to anticipated driver power demand variations.BACKGROUNDHybrid electric vehicles include internal combustion engines or, for short, engines that can be stopped and started while the vehicle is in motion. When the engine is stopped while the vehicle is in motion, the hybrid vehicle may operate in an "electric only" mode. A controller may issue instructions to stop (or "power down") or start (or "power up") to the engine in response to changes in the driver power demand.DE 10 2012 213 448 A1 discloses an engine start-stop prevention system and method. DE 198 34 417 A1 discloses a vehicle control system and a recording medium for recording programs for the system.SUMMARYA system and method for controlling a hybrid vehicle having an engine configured to automatically stop in response to an engine stop request and automatically start in response to an engine start request, according to the present disclosure, includes disabling an engine stop request based on the anticipated duration of an expected degraded performance condition commanded by the driver to reduce the occurrence of consecutive automatic stops and starts.In one embodiment, the anticipated duration of the expected degraded performance condition commanded by the driver is based on whether the vehicle is approaching a sink in a vehicle path. In another embodiment, the anticipated duration of the expected degraded performance condition commanded by the driver is based on whether the vehicle is approaching a highway entry or exit. In yet another embodiment, the anticipated duration of the expected degraded performance condition commanded by the driver is based on whether the vehicle is approaching an intersection. In another embodiment, the anticipated duration of the expected degraded performance condition commanded by the driver is based on whether the vehicle is turning. In yet another embodiment, the anticipated duration of the driver commanded degraded performance state is anticipated in response to a signal from at least one sensor including a navigation system, an optical camera, a radar or sonar system, a wireless data communication system, or a steering input sensor. Further, the method of the invention additionally includes retarding a vehicle transmission downshift or upshift in response to the anticipated duration of the driver commanded degraded power state.A method for controlling a vehicle having an engine with auto-stop and auto-start functions includes disabling the engine auto-start function in response to an anticipated increase and a subsequent decrease in driver commanded power.In one embodiment, the anticipated increase and subsequent decrease in a driver demand is based on whether the vehicle is approaching a hill. In another embodiment, the anticipated increase and subsequent decrease in a driver demand is based on whether the vehicle is approaching a second vehicle in an overtaking lane. In yet another embodiment, the anticipated increase and subsequent decrease in driver commanded power is based on a signal from at least one sensor, including a navigation system, an optical camera, a radar or sonar system, a wireless data communication system, or a steering input sensor.A hybrid electric vehicle according to the present disclosure includes a controller and an engine configured to stop in response to a request to shut down the engine and start in response to a request to shut down the engine. The controller is configured to disable a shutdown request issued due to a decrease in driver power demand, the disablement responsive to an anticipated subsequent increase in driver commanded power. The controller is further configured to disable a ramp-up request issued due to an increase in the driver power request, the disable being responsive to an anticipated subsequent decrease in driver commanded power.In one embodiment, the controller is configured to disable the ramp-down request in response to a detected approach of the vehicle to a valley in a vehicle path. In yet another embodiment, the controller is configured to disable the ramp-down request in response to a detected approach of the vehicle to a highway entry or exit. In another embodiment, the controller is configured to disable the ramp-down request in response to a detected approach of the vehicle to an intersection. In yet another embodiment, the controller is configured to disable the request to power down in response to an anticipated turn of the vehicle. In another embodiment, the controller is further configured to delay a vehicle transmission downshift or upshift in response to the anticipated decrease and subsequent increase in driver commanded power. In another embodiment, the controller is configured to disable the request to start up in response to a detected approach of the vehicle to a hill. In yet another embodiment, the controller is configured to disable the request to start up in response to a detected vehicle location in an overtaking lane and in response to an approach to a second vehicle.BRIEF DESCRIPTION OF THE DRAWINGSFIG. 1 is a schematic illustration of a hybrid electric vehicle having a modular configuration of the powertrain. FIG. 2 illustrates a vehicle having predictive control for running up and down an internal combustion engine. FIG. 3 illustrates a controller having a predictive function for running up and down an internal combustion engine. FIG. 4 is a flowchart illustrating a method of controlling an engine in a hybrid vehicle. FIGS. 5 aand 5 b illustrate examples of the operation of a predictive system for running an internal combustion engine up and down.DETAILED DESCRIPTIONEmbodiments of the present disclosure are described herein. It is to be understood, however, that the disclosed embodiments are merely examples and other embodiments may take various and alternative forms. The figures are not necessarily to scale; some features may be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the embodiments. Those of ordinary skill in the art will understand that various features illustrated and described with reference to any of the figures may be combined with features illustrated in one or more other figures to produce embodiments that are not explicitly illustrated or described. The combinations of features illustrated provide representative embodiments for typical applications. However, for certain applications or implementations, various combinations and modifications of the features may be desired that also conform to the teachings of the present disclosure.Referring to FIG. 1, a schematic diagram of a hybrid electric vehicle (HEV) 10 is shown in accordance with an embodiment of the present disclosure. FIG. 1 illustrates representative relationships among the components. The physical location and orientation of the components within the vehicle may vary. The HEV 10 includes a powertrain 12. the powertrain 12 includes an internal combustion engine 14 that drives a transmission 16, which may be referred to as a modular hybrid transmission (MHT). As will be described in more detail below, the transmission 16 includes an electric machine, such as an electric motor / generator (M / G) 18, an associated traction battery 20, a torque converter 22, and a multi-stage automatic transmission or transmission 24.The engine 14 and the M / G 18 are both sources of power for the HEV 10. The engine 14 generally represents a power source that may include an internal combustion engine, such as a gasoline, diesel, or natural gas powered internal combustion engine, or a fuel cell. The engine 14 generates engine power and corresponding engine torque that is provided to the M / G 18 when a disconnect clutch 26 between the engine 14 and the M / G 18 is at least partially engaged. The M / G 18 may be implemented by one of a plurality of types of electric machines. For example, the M / G 18 may be a permanent magnet synchronous motor. The power electronics 56 account for the direct current (DC) power provided by the battery 20 for the needs of the M / G 18, as will be described further below. For example, the power electronics may provide three phase alternating current (AC) to the M / G 18.When the disconnect clutch 26 is at least partially engaged, power flow from the engine 14 to the M / G 18 or from the M / G 18 to the engine 14 is possible. For example, disconnect clutch 26 may be engaged and M / G 18 may operate as a generator to convert the rotational energy provided by crankshaft 28 and M / G shaft 30 into electrical energy to be stored in battery 20. Disconnect clutch 26 may also be disengaged to disconnect engine 14 from the remainder of powertrain 12 such that M / G 18 may act as the sole source of propulsion for HEV 10. The M / G 18 is continuously drivingly connected to the shaft 30, whereas the engine 14 is drivingly connected to the shaft 30 only when the disconnect clutch 26 is at least partially engaged.The M / G 18 is connected to the torque converter 22 via the shaft 30. The torque converter 22 is thus connected to the engine 14 when the disconnect clutch 26 is at least partially engaged. Torque converter 22 includes an impeller fixed to M / G shaft 30 and a turbine fixed to transmission input shaft 32. Torque converter 22 thus provides hydraulic coupling between shaft 30 and transmission input shaft 32. The torque converter 22 transfers power from the impeller to the turbine when the impeller rotates faster than the turbine. The magnitudes of turbine torque and impeller torque generally depend on the relative speeds. If the impeller speed to turbine speed ratio is high enough, the turbine torque is a multiple of the impeller torque. A torque converter bypass clutch 34 may also be provided that, when engaged, frictionally or mechanically couples the impeller and turbine of the torque converter 22, enabling more efficient power transfer. The torque converter bypass clutch 34 may be operated as a launch clutch to provide a smooth vehicle launch. Alternatively, or in combination, a launch clutch similar to disconnect clutch 26 may be provided between M / G 18 and gearbox 24 for applications that do not include torque converter 22 or torque converter bypass clutch 34. In some applications, disconnect clutch 26 is commonly referred to as an upstream clutch and launch clutch 34 (which may be a torque converter bypass clutch) is commonly referred to as a downstream clutch.The transmission 24 may include gear sets (not shown) that are selectively placed in different gear ratios by selectively engaging friction elements, such as clutches and brakes (not shown), to establish the desired multiple discrete or step ratio ratios. The friction elements are controllable by a shift pattern that connects and disengages certain elements of the gear sets to control the ratio between a transmission output shaft 36 and the transmission input shaft 32. The gearbox 24 is automatically shifted from one gear ratio to another by an associated controller, such as a powertrain controller unit (PCU) 50, due to various operating conditions in the vehicle and environment. The pinion gear 24 then provides a powertrain output torque to the output shaft 36.It should be appreciated that the hydraulically controlled transmission 24 used with a torque converter 22 is just one example of a transmission or transmission arrangement; any multi-stage transmission that accepts input torque(s) from an internal combustion engine and / or an engine and then provides torque at the various gear ratios to an output shaft is suitable for use with the embodiments of the present disclosure. For example, the gear transmission 24 may be implemented by an automated mechanical (or manual) transmission (AMT) that includes one or more servomotors to translate / rotate shift forks along a shift rod to select a desired gear stage. As generally understood by those of ordinary skill in the art, an AMT may be used, for example, in applications with higher torque requirements.As shown in the representative embodiment of FIG. 1, the output shaft 36 is connected to a differential 40. The differential 40 drives a pair of wheels 42 via respective axles 44 connected to the differential 40. The differential transmits approximately the same torque to each wheel 42 but allows for slight speed differences, such as when the vehicle turns a corner. Various types of differentials or similar devices may be used to distribute torque from the powertrain to one or more wheels. In some applications, for example, the torque distribution may vary depending on the respective operating mode or conditions.The powertrain 12 further includes an associated powertrain control unit (PCU) 50. although the PCU 50 is shown as a controller, it may be part of a larger control system and may be controlled by various other controllers throughout the vehicle 10, such as a vehicle system controller (VSC). It is therefore understood that the powertrain control unit 50 and one or more other controllers may collectively be referred to as a "controller" that controls various actuators in response to signals from various sensors to control functions such as starting / stopping the engine 14, operating the M / G 18 to provide wheel torque or charge the battery 20, select or coordinate transmission shifts, etc. The controller 50 may include a microprocessor or central processing unit (CPU) in communication with various types of computer readable storage devices or media. For example, computer readable storage devices or media in read-only memory (ROM), random access memory (RAM), and keep-alive memory (KAM) may include volatile and nonvolatile memories. KAM is a persistent or non-volatile memory that can be used to store various operating parameters while the CPU is turned off. Computer readable storage devices or media may be implemented using any number of known storage devices, such as programmable read-only memories (PROMs), electrically EPROMs (PROM), EEPROMs (electrically erasable PROM), flash memory, or any other electrical, magnetic, optical, or combination storage devices capable of storing data, some of which represent executable instructions, used by the controller in controlling the engine or vehicle.The controller communicates with various engine / vehicle sensors and actuators via an input / output (I / O) interface, which may be implemented as a single integrated interface that provides various raw data or signal conditioning, processing and / or reforming, short circuit protection, and the like. Alternatively, one or more dedicated hardware or firmware chips may be used to contone and process particular signals before they are provided to the CPU. As generally shown in the representative embodiment of FIG. 1, the PCU 50 may communicate signals to and / or from engine 14, disconnect clutch 26, M / G 18, launch clutch 34, gearbox 24, and power electronics 56. Although not explicitly illustrated, those of ordinary skill in the art will recognize various functions or components that may be controlled by the PCU 50 within the subsystems identified above. Representative examples of the parameters, systems, and / or components that may be triggered / actuated directly or indirectly using control logic executed by the controller include control of timing, amount and duration of fuel injection, throttle valve position, spark timing control (for spark-ignition internal combustion engines), intake / exhaust valve timings and duration, front end accessory drive (FEAD) components such as alternator, air conditioner compressor, battery charge, regenerative braking, M / G operation, clutch pressures for disconnect clutch 26, launch clutch 34, and gearbox 24, and the like. Sensors communicating input through the I / O interface may be used to indicate turbocharger boost pressure, crankshaft position (PIP), engine speed (RPM), wheel speed (WS 1, WS 2), vehicle speed (VSS), coolant temperature (ECT), intake manifold pressure (MAP), vehicle accelerator pedal position (PPS), ignition switch position (IGN), throttle valve position (TP), air temperature (TMP), exhaust gas oxygen content (EGO), or other concentrations of exhaust gas components or their presence, intake air flow (MAF), transmission gear, ratio, or mode, transmission oil temperature (TOT), transmission turbine speed (TS), for example, Torque Converter Bypass Clutch 34 State (TCC), Deceleration or Shift Mode (MDE).Control logic or functions performed by the PCU 50 may be represented by flowcharts or similar diagrams in one or more figures. These figures provide representative control strategies and / or logic that may be implemented using one or more processing strategies such as event-driven, interrupt-driven, multi-tasking, multi-threading, and the like. As such, various steps or functions shown may be shown: in the sequence shown, or performed in parallel, or in some cases omitted. Although not always explicitly illustrated, one of ordinary skill in the art will recognize that one / r or more of the illustrated steps or functions may be repeatedly performed depending on the particular processing strategy being used. Likewise, the order of processing is not necessarily required to achieve the features and advantages described herein, but is intended to simplify the illustration and description. The control logic may be implemented primarily by software executed by a controller for the vehicle, engine, and / or powertrain based on a microprocessor such as the PCU 50. Of course, depending on the particular application, the control logic may be implemented as software, hardware, or a combination of software and hardware in one or more controllers. In an implementation as software, the control logic may be provided in one or more computer readable storage devices or media having stored data representing code or instructions executed by a computer to control the vehicle or its subsystems. The computer readable storage devices or media may include one or more of a number of known physical devices that utilize electrical, magnetic, and / or optical storage to store executable instructions and associated tuning information, operating parameters, and the like.A vehicle accelerator pedal 52 is used by the driver of the vehicle to provide the request for torque, power, or drive command to propel the vehicle. Generally, depression and release of the pedal 52 generates a vehicle accelerator pedal position signal that can be interpreted by the controller 50 as a request for increased and decreased performance, respectively. At least due to the pedal input, the controller 50 requests torque from the engine 14 and / or the M / G 18. The controller 50 also controls the timing of the gear shifts within the gearbox 24 as well as the engagement or disengagement of the disconnect clutch 26 and the torque converter bypass clutch 34. This creates a variable slip in the torque converter 22, in addition to the variable slip produced by the hydrodynamic coupling between the impeller and turbine. Alternatively, the torque converter bypass clutch 34 may be locked or open operated without the use of a modulated mode of operation depending on the particular application.To propel the vehicle with the engine 14, the disconnect clutch 26 is at least partially engaged to transfer at least a portion of the engine torque through the disconnect clutch 26 to the M / G 18, and then from the M / G 18 through the torque converter 22 and the gearbox 24. the M / G 18 may assist the engine 14 by providing additional power to rotate the shaft 30. This mode of operation may be referred to as a "hybrid mode" or an "auxiliary electrical mode.".To propel the vehicle with the M / G 18 as the sole power source, the power flow remains the same, except that the disconnect clutch 26 disconnects the engine 14 from the remainder of the powertrain 12. Combustion in engine 14 may be shut off during this time or otherwise stopped to conserve fuel. The engine 14 may be shut down or off in response to an engine stop request from a controller. For example, the traction battery 20 transfers stored electrical energy through the wiring 54 to power electronics 56, which may include an inverter. The power electronics 56 convert DC voltage from the battery 20 to AC voltage to be used by the M / G 18. The PCU 50 controls the power electronics 56 to convert voltage from the battery 20 to AC voltage, which is provided to the M / G 18 to supply positive or negative torque to the shaft 30. This mode of operation may be referred to as an "electric only" mode of operation.A controller, which may be the VSC or another controller if desired, may issue instructions to the PCU 50 to transition between different modes of operation. The instructions may include requests for engine start and stop, also known as requests for engine pull up / down (EPUD). EPUD requests may be made in response to various inputs including position variation of the vehicle accelerator pedal 52 and total driver power demand. For example, if the engine 14 is off and the vehicle accelerator pedal 52 is depressed, the controller may issue a request to start the engine up. In response to the request to start up the internal combustion engine, the same is started.In any operating mode, the M / G 18 may act as a motor and provide a motive force to the powertrain 12. Alternatively, the M / G 18 may act as a generator and convert kinetic energy from the powertrain 12 into electrical energy to be stored in the battery 20. For example, the M / G 18 may act as a generator while the engine 14 is providing propulsion power to the vehicle 10. The M / G 18 may additionally act as a generator during the duration of regenerative braking, where rotational energy from rotating wheels 42 is transferred back through the gearbox 24 and converted into electrical energy for storage in the battery 20.It is understood that the schematic illustration shown in FIG. 1 is merely exemplary and is not intended to be limiting. Other embodiments are conceivable that utilize a selected connection of both the engine and the engine to transmit through the transmission. For example, the M / G 18 may be offset from the crankshaft 28, an additional engine may be provided to start the engine 14, and / or the M / G 18 may be provided between the torque converter 22 and the gearbox 24. Other configurations are conceivable without departing from the scope of the present disclosure.During certain vehicle maneuvers, the EPUD logic serving as the basis may result in unsatisfactory vehicle behavior. For example, when the vehicle is driving into or out of a curve, merging into a highway entry or exit, or experiencing a small transient change in road grade due to road crossing, the EPUD logic serving as the base may result in unnecessary short EPUD requirements. Such EPUD requests result in a short term engine power turn-on or turn-off operation, which may result in less fuel economy and driver unsatisfaction. For example, in a scenario where the engine is activated and the vehicle is driving in a sharp curve, the driver will release the vehicle accelerator pedal while driving in the curve. In response to releasing the vehicle accelerator pedal, the EPUD logic serving as the base may issue a request to power down the engine. However, when the vehicle exits the curve, the driver may depress the vehicle accelerator pedal again, thereby causing the EPUD logic serving as the base to issue a request to start the engine up. This unnecessary engine deactivation and restarting may reduce fuel economy and driver satisfaction.Referring to FIG. 2, an HEV 58 is shown in schematic form. The HEV 58 may have a similar powertrain arrangement to that described above with reference to FIG. 1. The HEV 58 includes various sensors including a global positioning system (GPS) 60, a radar or sonar system 62, an optical camera 64, a road grade sensor 66, and a wireless communication system 68. The wireless communication system 68 may include WiFi, cellular data, Bluetooth, or other wireless communication devices. As indicated by the arrows, the sensors 60-68 are in communication with a controller 70. The controller 70, which may be a VSC or other controller, includes a predictive algorithm configured to predict upcoming road conditions. The predicted road conditions may indicate whether an EPUD request is necessary or appropriate. The controller 70 communicates with an engine stop / start controller 72, as indicated by the arrow. The powertrain torque controller 74 controls a motor / generator 78 and an engine 80. The transmission / clutch controller 76 controls a gear train 82 and an engine disconnect clutch 84.Referring to FIG. 3, an embodiment of an HEV 58' is shown in schematic form. HEV 58' includes a VSC 86. VSC 86 includes an EPUD logic module 88. EPUD logic module 88 outputs EPUD requests according to the base EPUD logic function in response to a total drive power command, a vehicle accelerator pedal position and change, and other inputs. The VSC 86 also receives predictive inputs from road conditions of other sensors or controllers. These sensors may include GPS, radar / sonar systems, optical cameras, road grade sensors, or wireless communication systems. The VSC 86 includes an EPUD predictive algorithm 92 The EPUD predictive algorithm 92 may modify the EPUD request in response to the road condition predictive inputs, as indicated in the table by the dashed line. The predictive EPUD algorithm 92 is configured to predict a decrease and subsequent increase in driver power demand in response to inputs indicating vehicle approach to a sink in the vehicle path, a highway entry or departure, an intersection, a turn of the vehicle, or other suitable scenarios. Similarly, the predictive EPUD algorithm 92 is configured to predict an increase and subsequent decrease in driver power demand in response to inputs indicating that the vehicle is approaching a hill in the vehicle path, an oncoming vehicle in an overtaking lane, or other suitable scenarios. The predictive EPCD algorithm 92 outputs a final engine start-up or shut-down request to an engine control module (ECM) 94. The ECM 94 may stop or start the engine in response to the request.Referring to FIG. 4, an embodiment of a predictive EPUD algorithm is illustrated. The algorithm begins at operation 96, where a determination is made as to whether the engine is running. If so, a determination is then made as to whether a shutdown request has been issued, as illustrated in operation 98. If no, control then returns to operation 96. If so, a determination is then made as to whether the shutdown request is based on a change in the driver power request or the vehicle accelerator pedal position, as shown in operation 100. If not, the engine is then stopped, as shown in block 102. Returning to operation 100, if a determination is made that the demand for ramp down is based on a change in the driver power demand or pedal position, then a prediction of the upcoming road conditions is made based on road condition inputs, as illustrated in block 104. A determination is then made based on the predicted road conditions as to whether a decrease and a subsequent increase in the driver power demand is anticipated, as illustrated in operation 106. This determination may be made generally as described above with reference to Figure 3. If no, then the engine is stopped, as shown in block 102. If yes, the engine shutdown request is then disabled, as illustrated in block 108. The disabling of the shutdown request is limited by a delay timer. In this way, the control logic avoids unnecessary engine running time if the driver's degraded power demand continues. A transmission downshift or upshift may also be disabled, as shown in block 110.Returning to operation 96, if a determination is made that the engine is not on, then a determination is made as to whether a power-up request has been issued, as illustrated in operation 112. If no, control then returns to operation 96. If so, a determination is made as to whether the request to power up is based on a change in the driver power request or the vehicle accelerator pedal position, as shown in operation 114. If no, the engine is then started, as illustrated in block 116. Returning to operation 114, if a determination is made that the request to ramp up is based on a change in the driver power request or pedal position, then a prediction of the upcoming road conditions is made based on road condition inputs, as illustrated in block 118. A determination is then made based on the predicted road conditions as to whether an increase and a subsequent decrease in the driver power demand is anticipated, as shown in operation 120. This determination may be made generally as described above with reference to Figure 3. If not, the engine is then started, as illustrated in block 116. If yes, the engine start-up request is then disabled, as illustrated in block 122. The disabling of the request to power up is limited by a delay timer. In this way, the control logic prevents battery discharge limits from being exceeded if the increase in driver power demand continues. An up or down shift of the transmission may also be inhibited, as illustrated in block 124.Referring to FIG. 5 a, an example of the operation of a method according to the present disclosure is illustrated. A vehicle 126 is equipped with a predictive EPUD system, generally as described above, and a series of sensors having a sensing range represented by the dashed lines. As the engine is running, the vehicle 126 approaches an intersection 128 that is controlled by a "pass-ahead" sign. Generally, a driver approaching a "pass-by" sign will release the vehicle accelerator while seeing after traffic, and then depress the vehicle accelerator when the road is clear. In response to the vehicle accelerator being released, the EPUD logic serving as the base may issue a request to power down the engine. Sensors in the vehicle detect that the vehicle is approaching the intersection 128. For example, a camera can visually recognize the "present" sign. In another example, a navigation system including map data may detect the approach of the vehicle to the intersection 128. Various other sensors may detect the approach to intersection 128 in a similar manner. In response to these inputs, the predictive EPUD system may predict a decrease and subsequent increase in the driver power demand and disable the shutdown request. If substantial cross traffic is detected at the intersection 128 by a radar, sonar, optical detection, or other means, then the predictive EPUD system may not predict a subsequent increase in the driver power demand and the engine is shut down.Referring to FIG. 5 b, another example of the operation of a method according to the present disclosure is illustrated. A vehicle 126' is equipped with a predictive EPUD system, generally as described above, and a series of sensors having a sensing range represented by the dashed lines. The vehicle 126' approaches a highway entrance 130. Generally, a driver approaching an entry will release the vehicle accelerator pedal to reduce the power demand during the time on the entry and then depress the vehicle accelerator pedal to increase the power demand as he merges with highway traffic. In response to the vehicle accelerator being released, the EPUD logic serving as the base may issue a request to power down the engine. Sensors in the vehicle detect that the vehicle is approaching ramp 130. For example, a navigation system having map data may recognize the approach of the vehicle to the ramp 130. Various other sensors may detect the approach to the ramp 130 in a similar manner. In response to these inputs, the predictive EPUD system may predict a decrease and subsequent increase in the driver power demand and disable the shutdown request.The disclosed method is described in the context of a hybrid vehicle having a modular powertrain. A similar method may of course be implemented in vehicles having other hybrid powertrain configurations, such as a parallel hybrid powertrain.The processes, methods, or algorithms disclosed herein may be communicated to / implemented by a processing device, controller, or computer, which may include any existing programmable electronic control unit or dedicated electronic control unit. Likewise, the processes, methods, or algorithms can be stored as data and instructions executable by a controller or computer in many forms including, but not limited to, information permanently stored on non-writable storage media such as ROM devices and information alterably stored on writeable storage media such as floppy disks, magnetic tape memories, CDs, RAM devices, and other magnetic and optical media. The processes, methods, or algorithms can also be implemented in a software executable object. Alternatively, the processes, methods, or algorithms can be implemented in whole or in part using suitable hardware components, such as application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), state machines, controllers or other hardware components or devices, or a combination of hardware, software, and firmware components.While exemplary embodiments have been described above, these embodiments do not describe all possible forms encompassed by the claims. The words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the disclosure. As described above, the features of various embodiments may be combined to form further embodiments of the invention that may not be explicitly described or illustrated. Although various embodiments may have been described as being advantageous or preferred over other embodiments or prior art implementations with respect to one or more desired characteristics, those of ordinary skill in the art recognize that one or more features or characteristics may be compromised to achieve desired overall system attributes, which depend on the particular application and implementation. These attributes may include, but are not limited to, cost, strength, durability, life cycle cost, marketability, appearance, packaging, size, serviceability, weight, mullability, ease of assembly, etc. As such, embodiments described as less desirable than other embodiments or prior art implementations with respect to one or more characteristics are not outside the scope of the disclosure and may be desirable for particular applications.A. A. Method of controlling a hybrid vehicle having an engine configured to automatically stop in response to an engine stop request and automatically start in response to an engine start request, the method comprising:disabling an engine stop request based on the anticipated duration of an expected degraded performance condition commanded by the driver to reduce the occurrence of consecutive automatic stops and automatic starts.B. The method of A, wherein the anticipated duration of the expected degraded performance condition commanded by the driver is based on whether the vehicle is approaching a sink in a vehicle path. C. The method of A, wherein the anticipated duration of the expected degraded performance condition commanded by the driver is based on whether the vehicle is approaching a highway entry or exit. D. The method of A, wherein the anticipated duration of the expected degraded performance condition commanded by the driver is based on whether the vehicle is approaching an intersection. E. The method of A, wherein the anticipated duration of the expected degraded performance condition commanded by the driver is based on whether the vehicle is turning. F. The method of A, wherein the anticipated duration of the expected degraded performance condition commanded by the driver is based on a signal from a navigation system, an optical camera, a radar, sonar, wireless data communication system, or a steering input sensor. G. The method of A, comprising further delaying a vehicle transmission downshift or upshift in response to the anticipated duration of the expected driver commanded degraded power state.H. A method of controlling a vehicle having an internal combustion engine with auto-stop and auto-start functions, the method comprising:locking the engine auto-start function in response to an anticipated increase and subsequent decrease in driver commanded power.I. The method of H, wherein the anticipated increase and subsequent decrease in driver demand is based on whether the vehicle is approaching a hill.J. The method of H, wherein the anticipated increase and subsequent decrease in a driver demand is based on whether the vehicle is in an overtaking lane and approaching a second vehicle.K. The method of H, wherein the anticipated increase and subsequent decrease in driver commanded power is based on a signal from a navigation system, an optical camera, a radar, sonar, wireless data communication system, or steering input sensors.L. Hybrid Electric Vehicle Comprising:an engine configured to stop in response to a shutdown request and start in response to a startup request; anda controller configured to disable a power down request issued due to a decrease in the driver power request in response to an anticipated subsequent increase in the driver commanded power, and disable a power up request issued due to an increase in the driver power request in response to an anticipated subsequent decrease in the driver commanded power.The M. hybrid electric vehicle of L, wherein the controller is further configured to disable the request to power down in response to a detected approach of the vehicle to a sink in a vehicle path.The N. hybrid electric vehicle of L, wherein the controller is further configured to disable the request to power down in response to a detected approach of the vehicle to a highway entry or exit.The O. hybrid electric vehicle of L, wherein the controller is further configured to disable the request to power down in response to a detected approach of the vehicle to an intersection.The P. hybrid electric vehicle of L, wherein the controller is further configured to disable the request to power down in response to an anticipated turn of the vehicle.The Q. hybrid electric vehicle of L, wherein the controller is further configured to delay a vehicle transmission downshift or upshift in response to the anticipated increase [and subsequent decrease] of a driver commanded power.The R. hybrid electric vehicle of L, wherein the controller is further configured to disable the request to start up in response to a detected approach of the vehicle to a hill.The S. hybrid electric vehicle of L, wherein the controller is further configured to disable the request to start up in response to a detected vehicle location on an overtaking lane with an approach to a second vehicle.EXPLANATION OF CHARACTERSFIG. 3 86 VEHICLE SYSTEM CONTROL DEVICE (VSC) TOTAL POWER DEMAND TOTAL DRIVE POWER COMMAND ACCELERATOR PEDAL VEHICLE ACCELERATOR PEDAL POSITION OTHER INPUTS 88 EPUD LOGIC EPUD REQUEST EPUD REQUEST 92 PREDICTIVE EPC ALGORITHM FINAL ENGINE PULL UP / PULL FINAL REQUEST OF DOWN REQUEST ENGINE TO START UP / DOWN 94 ENGINE CONTROL MODULE (ECM) ROAD CONDITION PREDICTIVE INPUTS OF INPUTS ROAD CONDITIONS PREDICTIVE A DECREASE AND THEN PREDICT DECREASE INCREASE IN POWER REQUEST: AND SUBSEQUENT INCREASE IN POWER REQUEST: APPROACH DEPRESSION TO A DECREASE IN VEHICLE PATH APPROACH TO AN APPROACH TO A RAMP HIGHWAY APPROACH OR APPROACH TO AN APPROACH TO AN INTERSECTION APPROACH TO AN APPROACH TO AN APPROACH TO AN INTERSECTION APPROACH A VEHICLE TURN Approach to a turn of the vehicle predictive of increase and decrease in power request: subsequent decrease of a power demand: approaching hill in vehicle approach to a hill in the path of the vehicle approach to an approach to another while in passing lane vehicle in the passing lane FIG. 4 NO YES 96 ENGINE ON? 98 REQUEST TO POWER DOWN? 100 POWER REQUEST BASED ON DRIVER OR VEHICLE ACCELERATOR PEDAL REQUEST? 104 RECEIVE ROAD CONDITION INPUTS; PREDICT IMMINENT ROAD CONDITIONS 106 PREDICTED DECREASE AND SUBSEQUENT INCREASE IN DRIVER POWER REQUEST? 108 DISABLE REQUEST TO POWER DOWN (UNTIL TIMER ENDS) 110 DISABLE TRANSMISSION UPSHIFT / DOWNSHIFT 102 STOP ENGINE 112 REQUEST TO POWER UP? 114 POWER REQUEST BASED ON DRIVER OR VEHICLE ACCELERATOR PEDAL REQUEST? 116 START ENGINE 118 RECEIVE ROAD CONDITION INPUTS; PREDICT IMMINENT ROAD CONDITIONS 120 PREDICTED INCREASE AND SUBSEQUENT DECREASE DRIVER POWER REQUEST? 122 DISABLE REQUEST TO POWER UP (UNTIL TIMER ENDS) 124 DISABLE TRANSMISSION UPSHIFT / DOWNSHIFT

Claims

A method of controlling a hybrid vehicle (10, 126) having an engine (14) configured to automatically stop in response to an engine stop request and automatically start in response to an engine start request, the method comprising: disabling an engine stop request based on the anticipated duration of an expected driver commanded degraded power state to reduce the occurrence of consecutive automatic stops and automatic starts; and delaying a vehicle transmission (16) downshift or upshift in response to the anticipated duration of the expected driver commanded degraded power state.The method of claim 1, wherein the anticipated duration of the expected degraded performance condition commanded by the driver is based on whether the vehicle (10, 126) is approaching a sink in a vehicle path.The method of claim 1, wherein the anticipated duration of the expected degraded performance condition commanded by the driver is based on whether the vehicle (10, 126) is approaching a highway entry or exit (130).The method of claim 1, wherein the anticipated duration of the expected degraded performance condition commanded by the driver is based on whether the vehicle (10, 126) is approaching an intersection (128).The method of claim 1, wherein the anticipated duration of the expected degraded performance condition commanded by the driver is based on whether the vehicle (10, 126) is turning.The method of claim 1, wherein the anticipated duration of the expected degraded performance condition commanded by the driver is based on a signal from a navigation system, an optical camera (64), a radar (62), sonar (62), wireless data communication system (68), or a steering input sensor.

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