System and method for engine start adaptation

Abstract

The present disclosure provides a system and method for engine start adaptation. Methods and systems are described for adapting an engine start threshold for an automatic engine start. In one example, one or more engine autostart thresholds may be adjusted to reduce the likelihood of engine autostart. The engine auto-start threshold may be adjusted based on the engine start being characterized as a low-benefit engine start.

Description

Technical Field

[0001] This specification generally relates to systems and methods for starting an internal combustion engine of a vehicle. Background Art

[0002] Hybrid vehicles can sometimes operate only on electric propulsion power. Electricity provides an opportunity to save gasoline or diesel fuel and reduce vehicle emissions. However, the electric propulsion can be replaced or augmented by power generated by an internal combustion engine. If the engine starts and the engine does not remain started for a threshold amount of time, the engine start can be considered a low-benefit engine start. It may be desirable to reduce the likelihood of generating a low-benefit engine start. Summary of the Invention

[0003] The engine of a hybrid vehicle can automatically start during periods of high driver demand and a low state of charge (SOC) of the battery (e.g., start in response to vehicle operating conditions rather than in response to a human or autonomous driver engine start request). High driver demand can have different causes, including but not limited to high road loads, high vehicle loads, and aggressive driver behavior. In some examples, high driver demand caused by aggressive driver behavior may not be maintained for a long period of time because this may cause the vehicle speed to increase to a speed higher than the speed desired by the vehicle driver. For example, some aggressive drivers may tend to input a large driver demand for a short period of time and then the driver demand drops significantly. This may cause the engine to start and then stop shortly thereafter. However, if the driver may have a more gradually increasing driver demand, the vehicle speed may have increased at a reasonable rate without having to start the engine.

[0004] In one example, the above problem can be solved by a method for operating a vehicle, the method comprising: adjusting one or more engine automatic start thresholds in response to multiple low-benefit engine starts.

[0005] By adjusting the automatic engine start threshold in response to multiple low-benefit engine starts, the likelihood of generating a low-benefit engine start can be reduced. For example, the threshold amount of time that the driver demand torque is greater than a threshold torque amount before the internal combustion engine automatically starts can be increased, such that the internal combustion engine can automatically start less frequently due to a rapid application and withdrawal of the driver demand torque.

[0006] The methods described herein can have several advantages. Specifically, the method can reduce the frequency of low-benefit engine starts. In addition, the method can reduce fuel consumption and engine start busyness. Additionally, the method is applicable to different vehicle drivers.

[0007] It will be appreciated that the above invention content is provided to introduce, in a simplified form, a series of concepts that are further described in the detailed description. This does not mean identifying the key features of the claimed subject matter, the scope of which is uniquely defined by the claims appended to the detailed description. Moreover, the claimed subject matter is not limited to implementations that solve any disadvantages mentioned above or in any part of this disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 is a schematic diagram of an engine system for a hybrid vehicle system.

[0009] Figure 2 Shows an exemplary powertrain of a hybrid vehicle.

[0010] Figure 3 Shows an exemplary sequence for operating a hybrid vehicle.

[0011] Figures 4 to 6 Shows a method for operating a hybrid vehicle. DETAILED DESCRIPTION

[0012] The following description relates to systems and methods for adjusting conditions for automatically starting an engine of a hybrid vehicle. In one example, a hybrid vehicle may include Figure 1 an engine of the type shown. The hybrid vehicle may be arranged in a power split configuration, a series configuration, or a parallel configuration as Figure 2 shown. The hybrid vehicle may be operated according to the Figures 4 to 6 method, as shown in the Figure 3 sequence. The hybrid vehicle may adjust a threshold for automatic engine starting according to the Figures 4 to 6 method.

[0013] Referring to Figure 1 , an internal combustion engine 10 is shown. The engine 10 may be included in a driveline of a vehicle 100 configured for road propulsion, such as Figure 2 the powertrain shown. In one example, the vehicle 100 is a hybrid electric vehicle.

[0014] The engine 10 (including a plurality of cylinders ( Figure 1One of the cylinders is shown to be controlled by the electronic engine controller 12. The engine 10 consists of a cylinder head 35 and a cylinder block 33, and the cylinder head and the cylinder block include a combustion chamber 30 and a cylinder wall 32. A piston 36 is positioned therein and reciprocates via a connection with a crankshaft 40. A flywheel 97 and a ring gear 99 are coupled to the crankshaft 40. An optional starter 96 (e.g., a low voltage (operating at less than 30 volts) motor) is included for rotating the starting engine during engine starting. The starter 96 includes a pinion shaft 98 and a pinion 95. The pinion shaft 98 can selectively advance the pinion 95 to engage the ring gear 99. The starter 96 can be directly mounted to the front or the rear of the engine. In some examples, the starter 96 can selectively supply torque to the crankshaft 40 via a drive connection or a chain to initiate engine rotation during engine starting. Once a threshold engine speed is reached, the starter can be disengaged from the engine, and thereafter engine rotation is maintained via fuel combustion in the engine cylinders. In one example, the starter 96 is in a basic state when not engaged to the engine crankshaft.

[0015] The combustion chamber 30 is shown to communicate with an intake manifold 44 and an exhaust manifold 48 via respective intake valves 52 and exhaust valves 54. Each intake valve and exhaust valve can be operated by an intake cam 51 and an exhaust cam 53. The position of the intake cam 51 can be determined by an intake cam sensor 55. The position of the exhaust cam 53 can be determined by an exhaust cam sensor 57. The intake valve 52 can be selectively actuated and deactivated by a valve actuation device 59. The exhaust valve 54 can be selectively actuated and deactivated by a valve actuation device 58. The valve actuation devices 58 and 59 can be electromechanical devices.

[0016] A fuel injector 66 is shown to be positioned to inject fuel directly into the combustion chamber 30, which is known to those skilled in the art as direct injection. The fuel injector 66 delivers liquid fuel in proportion to the pulse width from the controller 12. The fuel is delivered to the fuel injector 66 through a fuel system (not shown), which includes a fuel tank, a fuel pump, and a fuel rail (not shown). In one example, a high-pressure dual-stage fuel system can be used to generate a higher fuel pressure. In a further embodiment, the fuel can be delivered to an intake passage upstream of the intake valve 52 leading to the combustion chamber 30 to provide port injection of fuel. In an even further embodiment, a portion of the cylinder fuel can be delivered via direct injection, while the remainder is delivered via port injection. Different injectors can deliver the same fuel or fuels of different properties, such as gasoline fuel and ethanol fuel.

[0017] The intake manifold 44 is shown in communication with the turbocharger compressor 162 and the engine intake port 42. In other examples, the compressor 162 can be a supercharger compressor. The shaft 161 mechanically couples the turbocharger turbine 164 to the turbocharger compressor 162. The optional electronic throttle 62 adjusts the position of the throttle plate 64 to control the airflow from the compressor 162 to the intake manifold 44. Since the inlet of the throttle 62 is within the boost chamber 45, the pressure in the boost chamber 45 can be referred to as the throttle inlet pressure. The throttle outlet is in the intake manifold 44. In some examples, the throttle 62 and the throttle plate 64 can be positioned between the intake valve 52 and the intake manifold 44 such that the throttle 62 is an intake passage throttle. The compressor recirculation valve (CRV) 47 can be selectively adjusted to a plurality of positions between fully open and fully closed. Adjusting the opening of the CRV 47 allows boost air to be selectively recirculated upstream of the compressor, thereby reducing the pressure in the boost chamber 45. The wastegate 163 can be adjusted via the controller 12 to allow the exhaust gas to selectively bypass the turbine 164, thereby controlling the speed of the compressor 162. The air cleaner 43 cleans the air entering the engine intake port 42.

[0018] The distributorless ignition system 88 provides an ignition spark to the combustion chamber 30 via the spark plug 92 in response to the controller 12. The universal exhaust gas oxygen (UEGO) sensor 126 is shown coupled to the exhaust manifold 48 upstream of the catalytic converter 70. Alternatively, a two-state exhaust gas oxygen sensor can replace the UEGO sensor 126.

[0019] In one example, the converter 70 can include a plurality of catalyst bricks. In another example, a plurality of emission control devices each having multiple bricks can be used. In one example, the converter 70 can be a three-way type catalyst.

[0020] The controller 12 is in Figure 1shown as a conventional microcomputer, the conventional microcomputer including: a microprocessor unit 102, an input / output port 104, a read-only memory 106 (e.g., non-transitory memory), a random access memory 108, a keep-alive memory 110, and a conventional data bus. In addition to those signals previously discussed, controller 12 is shown as also receiving various signals from sensors coupled to engine 10, including: engine coolant temperature (ECT) from temperature sensor 112 coupled to coolant jacket 114; a position sensor 134 coupled to driver demand pedal 130 for sensing the force applied by foot 132; a position sensor 154 coupled to vehicle deceleration pedal 150 for sensing the force applied by foot 152; a measurement of engine manifold pressure (MAP) from pressure sensor 122 coupled to intake manifold 44; an engine position sensor from engine position sensor 118 sensing the position of crankshaft 40; a measurement of the air mass entering the engine from sensor 120; and a measurement of throttle position from sensor 68. The driver demand pedal and the vehicle deceleration pedal may be combined, for example, in a pivot arrangement to select an increase or decrease in vehicle speed. Additionally, the driver demand pedal may be combined with transmission direction selection (e.g., joystick control). Atmospheric pressure may also be sensed (sensor not shown) for processing by controller 12. In a preferred aspect of the present specification, for each revolution of the crankshaft, engine position sensor 118 generates a predetermined number of equally spaced pulses, whereby the engine speed (RPM) can be determined.

[0021] Controller 12 may also receive operator input via a gear shift lever or shift selector 136. Shift selector 136 may be manually shifted by a vehicle operator between different gear options based on a desired transmission output and a desired vehicle direction of movement. In one example, as depicted, the operator may have the following operator-selectable options: park (P), reverse (R), neutral (N), and drive (D). In the depicted example, the shift selector is referred to as a PRNDL joystick corresponding to the different options. In one example, when in park or neutral, substantially no torque can be transmitted from the engine or motor to the transmission output. When in park, the vehicle is stationary. In drive, the electronic controller may control the transmission to propel the vehicle in the forward direction. In reverse, the controller enables the vehicle to move in the reverse or backward direction. Shift selector 136 may be located on the vehicle's steering column or between the driver and passenger positions. Additionally, the transmission may be configured as Figure 2 shown in more detail herein.

[0022] Controller 12 receives signals from Figure 1 various sensors and employs Figure 1Various actuators (such as throttle 62, fuel injector 66, spark plug 92, etc.) adjust engine operation based on the received signals and instructions stored in the controller's memory. As an example, the controller may send a pulse width signal to the fuel injector to adjust the amount of fuel delivered to the cylinder. Additionally, controller 12 may receive input from a human operator or a vehicle passenger via the human / machine interface 195. The human / machine interface may be a touch screen, a touch panel, a key switch, or other known input devices.

[0023] During operation, each cylinder within engine 10 typically undergoes a four-stroke cycle: the cycle includes an intake stroke, a compression stroke, an expansion stroke, and an exhaust stroke. During the intake stroke, generally, the exhaust valve 54 is closed and the intake valve 52 is open. Air is introduced into the combustion chamber 30 via the intake manifold 44, and the piston 36 moves to the bottom of the cylinder to increase the volume within the combustion chamber 30. The position where the piston 36 is near the bottom of the cylinder and at the end of its stroke (e.g., when the combustion chamber 30 is at its maximum volume) is typically referred to by those skilled in the art as the bottom dead center (BDC).

[0024] During the compression stroke, both the intake valve 52 and the exhaust valve 54 are closed. The piston 36 moves toward the cylinder head to compress the air within the combustion chamber 30. The point where the piston 36 is at the end of its stroke and closest to the cylinder head (e.g., when the combustion chamber 30 is at its minimum volume) is typically referred to by those skilled in the art as the top dead center (TDC). During a process hereinafter referred to as injection, fuel is introduced into the combustion chamber. During a process hereinafter referred to as ignition, the injected fuel is ignited by a known ignition device such as the spark plug 92, resulting in combustion.

[0025] During the expansion stroke, the expanding gases push the piston 36 back to the BDC. The crankshaft 40 converts the piston movement into rotational torque of the rotating shaft. Finally, during the exhaust stroke, the exhaust valve 54 opens to release the burned air-fuel mixture into the exhaust manifold 48, and the piston returns to the TDC. It should be noted that the above is shown merely as an example, and the opening and / or closing timing of the intake and exhaust valves may vary, such as to provide positive or negative valve overlap, late intake valve closing, or various other examples.

[0026] Figure 2 An exemplary propulsion system 200 for a vehicle 100 is depicted. In the depicted embodiment, the vehicle is a hybrid electric vehicle (HEV). The propulsion system 200 includes an internal combustion engine 10 having a plurality of combustion chambers 30 (such as Figure 1The engine 10). Fuel can be supplied to each cylinder of the engine 10 from a fuel system (not shown) including one or more fuel tanks, one or more fuel pumps, and fuel injectors 66. When the vehicle 100 moves in the forward direction 203, the front portion 202 is in front of the vehicle 100. When the vehicle 100 moves in the reverse direction 205, the rear portion 204 is in front of the vehicle 100.

[0027] The engine 10 delivers power to the transmission 157 via a torque input shaft 18. In the depicted example, the transmission 157 is a power-split transmission (or transaxle) that includes a planetary gear set 22 and one or more rotating gear elements. The transmission 157 also includes a first electric machine 24 (EM1) and a second electric machine 26 (EM2). The first electric machine 24 and the second electric machine 26 can operate as motors or generators. Torque is output from the transmission 157 for propelling the vehicle drive wheels 155 via a powertrain 34, a torque output shaft 19, and an axle 288. The axle 288 is shown as a rear axle, but in some examples, it can be a front axle. The axle 288 can include a differential assembly 236, a right half shaft 287, and a left half shaft 289.

[0028] The first electric machine 24 is drivingly connected to the second electric machine 26 such that each of the first electric machine 24 and the second electric machine 26 can operate using electrical energy from an electrical energy storage device (depicted herein as a battery 158). In some embodiments, an energy conversion device such as an inverter can be coupled between the battery and the motor to convert the DC output of the battery into an AC output for use by the motor. However, in alternative embodiments, the inverter can be configured within the motor. Due to the mechanical characteristics of the planetary gear set, the first electric machine 24 can be driven by a power output element (on the output side) of the planetary gear set 22 via a mechanical connection 232, as further detailed below.

[0029] The second electric machine 26 can operate in a regenerative mode, i.e., as a generator, to absorb energy from vehicle motion and / or the engine and convert the absorbed kinetic energy into a form of energy suitable for storage in the battery 158. Additionally, the second electric machine 26 can operate as a motor or a generator as needed to augment or absorb torque provided by the engine, such as during a transition of the engine 10 between different combustion modes (e.g., during a transition between spark ignition mode and compression ignition mode).

[0030] The planetary gear set 22 includes a ring gear 142, a sun gear 143, and a carrier assembly 146. The ring gear and the sun gear can be coupled to each other via the carrier assembly 146. The carrier assembly 146 can include planet pinions 147 and a carrier for supporting the planet pinions. The carrier assembly 146 is directly coupled to the engine 10 without an intermediate sun gear or ring gear. The sun gear 143 is directly coupled to the first electric machine 24 without an intermediate carrier assembly 146 or ring gear 142. The ring gear 142 is directly coupled to the power transmission 34, and the transmission 34 is coupled to the vehicle traction wheels 155. The power transmission 34 can include one or more meshing gear elements 260-268. The second electric machine 26 can drive a gear element 270 that serves as a torque input to the gear elements 260-268. In this way, the ring gear 142 (and thus the engine and the first electric machine) can be coupled to the wheels and the motor via one or more gear elements. The operator can select a transmission mode via actuation of the shift selector 136, as discussed in Figure 1 as discussed.

[0031] The controller 12 can command and control the first electric machine 24 and the second electric machine 26, as well as the engine 10, the battery 158, and the friction pad 291. In some examples, the controller 12 can be embodied as two or more controllers. The controller 12 can be configured to receive information from a plurality of sensors 16 (various examples of which are described herein) and send control signals to a plurality of actuators 81 (various examples of which are described herein). As an example, the sensors 16 can include various pressure and temperature sensors, fuel level sensors, various exhaust sensors, etc. Input can also be received via the shift selector 136, the vehicle deceleration pedal, the driver demand pedal, the vehicle speed sensor, and Figure 1 other sensors. The various actuators can include, for example, gear sets, cylinder fuel injectors (not shown), an intake throttle coupled to the engine intake manifold (not shown), and Figure 1 other actuators. The controller 12 can receive input data from the various sensors, process the input data, and trigger the actuators in response to the processed input data based on instructions or code corresponding to one or more control routines programmed therein.

[0032] For example, frictional force can be applied to the wheel 155 by engaging the friction pad 291 to decelerate the vehicle 100. In one example, the friction pad 291 can engage in response to a driver pressing their foot on a vehicle deceleration pedal (not shown). The friction pad control module of the controller 12 can adjust the torque applied to the wheel via the friction pad in accordance with the engine deceleration torque from the engine 10 and / or the negative motor torque from the second motor 26 (e.g., torque opposite to the motor rotation) so as to apply a net torque amount on the wheel that slows down the forward movement of the vehicle at a target vehicle speed reduction rate. In the same manner, the frictional force on the wheel 155 can be reduced by disengaging the friction pad 291 in response to the driver releasing their foot from the vehicle deceleration pedal or the forward vehicle speed dropping below a threshold.

[0033] The vehicle 100 can operate in at least four different operating modes. The four operating modes include a forward electric vehicle mode, a reverse electric vehicle mode, an extended range forward mode, and an engine cranking start mode. In these four modes, the vehicle 100 can be driven only by the engine 10, driven by the engine 10 in cooperation with the first motor and / or the second motor, or driven only by the motors, or driven by a combination thereof.

[0034] For example, the vehicle can be driven in a first forward electric vehicle mode, where the engine 10 does not rotate, and either or both of the first motor 24 and the second motor 26 provide propulsion force to drive the vehicle 100 in the forward direction. In the reverse electric vehicle mode, the engine 10 does not rotate, and either or both of the first motor 24 and the second motor 26 provide propulsion force to propel the vehicle 100 in the reverse direction. In the extended range mode, the engine 10 rotates and provides torque to the propulsion system 200 to propel the vehicle 100, and / or charges the battery 158, and / or transfers electrical power from the first motor 24 to the second motor 26, and vice versa. In the engine cranking start mode, the first motor rotates the engine 10 while the vehicle 100 remains stationary. The second motor prevents the ring gear 142 from rotating.

[0035] Therefore, Figure 1 and Figure 2The system provides a vehicle system that includes: an electric motor; an internal combustion engine; and a controller that includes executable instructions that cause the controller to adjust one or more engine auto-start thresholds in response to a behavior classification that has been characterized as an aggressive human vehicle driver. In a first example, the vehicle system includes: wherein the behavior classification is based on the rate of change of the pedal position. In a second example that may include the first example, the vehicle system includes: wherein the behavior classification is based on the rate of change of the pedal speed. In a third example that may include one or both of the first example and the second example, the vehicle system includes: wherein the behavior classification is based on a driver demand change frequency greater than a threshold. In a fourth example that may include one or more of the first example through the third example, the vehicle system includes: wherein the behavior classification is based on pedal movement. In a fifth example that may include one or more of the first example through the fourth example, the vehicle system includes: wherein one of the one or more engine auto-start thresholds is an amount of estimated work performed by the internal combustion engine. In a sixth example that may include one or more of the first example through the fifth example, the vehicle system further includes additional executable instructions for starting the internal combustion engine in response to the one or more engine auto-start thresholds being exceeded. In a seventh example that may include one or more of the first through sixth examples, the vehicle system further includes additional executable instructions for adjusting the one or more engine auto-start thresholds in response to multiple low-benefit engine starts.

[0036] Now refer to Figure 3 , an exemplary vehicle operation sequence is shown. Figure 3 The vehicle operation sequence of Figure 1 and Figure 2 The vehicle of Figures 4 to 6 The method of

[0037] From Figure 3The first graph starting from the top is a graph of the ratio between the actual total number of inefficient engine starts based on the driver demand for a specific vehicle human driver and the actual total number of engine starts over a predetermined interval versus time. The vertical axis represents the ratio between the actual total number of inefficient engine starts based on the driver demand for a specific vehicle human driver and the actual total number of engine starts over a predetermined interval. The horizontal axis represents time, and time increases from the left side of the graph to the right side of the graph. Trace 302 represents the ratio between the actual total number of inefficient engine starts based on the driver demand for a specific vehicle human driver and the actual total number of engine starts over a predetermined interval. Horizontal line 350 represents the threshold that is to be exceeded to adjust the automatic engine start threshold.

[0038] Starting from Figure 3 The second graph starting from the top is a graph of the actual total number of engine starts based on the driver demand for a specific vehicle human driver over a predetermined interval versus time. The vertical axis represents the actual total number of engine starts based on the driver demand for a specific vehicle human driver over a predetermined interval. The horizontal axis represents time, and time increases from the left side of the graph to the right side of the graph. Trace 304 represents the actual total number of engine starts based on the driver demand for a specific vehicle human driver over a predetermined interval. Horizontal line 352 represents the threshold that is to be exceeded to adjust the automatic engine start threshold.

[0039] Starting from Figure 3 The third graph starting from the top is a graph of the driver demand torque or power threshold for initiating an automatic engine start versus time. The vertical axis represents the driver demand torque or power threshold for initiating an automatic engine start. The horizontal axis represents time, and time increases from the left side of the graph to the right side of the graph. Trace 306 represents the driver demand torque or power threshold for initiating an automatic engine start, and the amount of the driver demand torque or power threshold increases in the direction of the vertical axis arrow. When the driver demand torque or power exceeds the threshold represented by trace 306, an automatic engine start can be initiated.

[0040] Starting from Figure 3 The fourth graph starting from the top is a graph of the amount of time that the driver demand exceeds the threshold driver demand for initiating an automatic engine start versus time. The vertical axis represents the amount of time that the driver demand exceeds the threshold driver demand for initiating an automatic engine start. The horizontal axis represents time, and time increases from the left side of the graph to the right side of the graph. Trace 306 represents the amount of time that the driver demand exceeds the threshold driver demand for initiating an automatic engine start. When the amount of time that the driver demand torque or power exceeds the threshold is represented by trace 308, an automatic engine start can be initiated.

[0041] From Figure 3 The fifth graph starting from the top of Figure 3 is a graph of the driver demand filter smoothing factor versus time. The vertical axis represents the driver demand filter smoothing factor value, and the driver demand filter smoothing factor value increases in the direction of the arrow on the vertical axis. The horizontal axis represents time, and time increases from the left side of the graph to the right side of the graph. Trace 310 represents the driver demand smoothing factor value. In one example, the smoothing factor can be applied via a first-order filter expressed as y i = αx i +(1 - α)y (i-1) where α is the smoothing factor, x is the input of the filter, y is the output of the filter, and i is the data point sample number.

[0042] At time t0, the ratio between the actual total number of low-benefit engine starts based on the driver demand for a particular vehicle driver and the actual total number of engine starts is low, and the actual total number of engine starts based on the driver demand for a particular vehicle driver is also low. The driver demand torque or power threshold for initiating an automatic engine start, the amount of time the driver demand exceeds the driver demand threshold for initiating an automatic engine start, and the driver demand filter smoothing factor are at a medium level.

[0043] At time t1, the ratio between the actual total number of low-benefit engine starts based on the driver demand for a particular vehicle driver and the actual total number of engine starts has increased, but it remains below the threshold 350. Therefore, the driver demand torque or power threshold for initiating an automatic engine start, the amount of time the driver demand exceeds the threshold driver demand for initiating an automatic engine start, and the driver demand filter smoothing factor are not adjusted. The actual total number of engine starts based on the driver demand for a particular vehicle driver has increased, and it now exceeds the threshold 352. Therefore, the actual total number of engine starts based on the driver demand for a particular vehicle driver does not prevent the adjustment of the driver demand torque or power threshold for initiating an automatic engine start, the amount of time the driver demand exceeds the driver demand threshold for initiating an automatic engine start, and the driver demand filter smoothing factor.

[0044] At time t2, the ratio between the actual total number of low-benefit engine starts based on the driver demand for a particular vehicle driver and the actual total number of engine starts has increased and is now greater than the threshold 350. Therefore, the driver demand torque or power threshold for initiating an automatic engine start, the amount of time that the driver demand exceeds the threshold driver demand for initiating an automatic engine start, and the driver demand filter smoothing factor are adjusted. The actual total number of engine starts based on the driver demand for a particular vehicle driver remains higher than the threshold 352. Accordingly, the driver demand torque or power threshold for initiating an automatic engine start is increased, the amount of time that the driver demand exceeds the driver demand threshold for initiating an automatic engine start is increased, and the driver demand filter smoothing factor is increased. These adjustments can operate to reduce the likelihood of an automatic engine start.

[0045] Move to Figures 4 to 6 , which shows a method for operating a hybrid vehicle. Specifically, Figures 4 to 6 The method can be incorporated as executable instructions stored in the non-transitory memory of the controller Figure 1 and Figure 2 in the system. Additionally, other portions of method 400 can be executed by a controller that transforms the operating states of the devices and actuators in the physical world. The controller can employ the engine actuators of the engine system to adjust engine operation.

[0046] At 402, method 400 determines whether the most recent automatic engine start (e.g., an engine start initiated via the controller without an explicit request from the vehicle driver or occupant to start the internal combustion engine) is in response to a driver demand level. If so, the answer is yes and method 400 proceeds to 404. Otherwise, the answer is no and method 400 proceeds to 470.

[0047] At 470, method 400 maintains the thresholds and / or parameters for automatic engine start at their existing levels or values. Method 400 proceeds to exit.

[0048] At 404, method 400 determines whether, after the most recent automatic engine start, the engine has had a continuous run time less than a threshold amount of time within a predetermined time interval (e.g., rotating the engine and burning fuel without stopping the engine). If so, the answer is yes and method 400 proceeds to 405. If not, the answer is no and method 400 proceeds to 406. A short duration of the engine run time within a predetermined amount of time can indicate a lack of actual necessity to utilize the engine output.

[0049] At 405, method 400 indicates that the most recent automatic engine start is a low-benefit engine start and increments a counter that stores the actual total number of low-benefit engine starts for the current vehicle driver. Method 400 proceeds to 414.

[0050] At 406, method 400 determines whether, after the most recent automatic engine start, the engine has performed an amount of work that is less than a threshold amount of work to propel the vehicle and / or charge the traction battery during a predetermined time interval. If so, the answer is yes and method 400 proceeds to 407. If not, the answer is no and method 400 proceeds to 408. The engine performing a small amount of work within a predetermined amount of time may indicate a lack of need to utilize the engine output.

[0051] At 407, method 400 indicates that the most recent automatic engine start is a low-benefit engine start and increments a counter that stores the actual total number of low-benefit engine starts for the current vehicle driver. Method 400 proceeds to 414.

[0052] At 408, method 400 determines whether the amount of time that the driver demand has exceeded a threshold driver demand after the most recent automatic engine start is less than a threshold amount of time. If so, the answer is yes and method 400 proceeds to 409. If not, the answer is no and method 400 proceeds to 410. A short duration during which the driver demand exceeds the threshold may indicate an inefficient use of the engine output.

[0053] At 409, method 400 indicates that the most recent automatic engine start is a low-benefit engine start and increments a counter that stores the actual total number of low-benefit engine starts for the current vehicle driver. Method 400 proceeds to 414.

[0054] At 410, method 400 determines whether, after the most recent automatic engine start, during a predetermined duration, the average engine speed is less than a threshold speed, the average engine torque is less than a threshold torque, and the average driver demand is less than a threshold driver torque demand. If so, the answer is yes and method 400 proceeds to 412. If not, the answer is no and method 400 proceeds to 411. Low engine speed and low engine torque may indicate inefficient engine operation.

[0055] At 411, method 400 indicates that the most recent automatic engine start is a low-benefit engine start and increments a counter that stores the actual total number of low-benefit engine starts for the current vehicle driver. Method 400 proceeds to 414.

[0056] At 412, method 400 determines whether the engine fuel efficiency is less than a threshold efficiency within a predetermined time interval after the most recent automatic engine start. If so, the answer is yes, and method 400 proceeds to 413. If not, the answer is no, and method 400 proceeds to 414.

[0057] At 413, method 400 indicates that the most recent automatic engine start is a low - efficiency engine start and increments a counter that stores the actual total number of low - efficiency engine starts for the current vehicle driver. Method 400 proceeds to 414.

[0058] At 414, method 400 determines whether the frequency of the rate of change of the pedal (e.g., driver demand pedal or vehicle deceleration pedal) application position is greater than a threshold position rate of change after the most recent automatic engine start. If so, the answer is yes, and method 400 proceeds to 415. If not, the answer is no, and method 400 proceeds to 416.

[0059] At 415, method 400 indicates that the vehicle is being operated by a driver characterized as "aggressive" after the most recent engine automatic start. Method 400 proceeds to 422.

[0060] At 416, method 400 determines whether the frequency of the rate of change of the pedal application speed is greater than a threshold speed rate of change after the most recent automatic engine start. If so, the answer is yes, and method 400 proceeds to 417. If not, the answer is no, and method 400 proceeds to 418.

[0061] At 417, method 400 indicates that the vehicle is being operated by a driver characterized as "aggressive" after the most recent engine automatic start. Method 400 proceeds to 422.

[0062] At 418, method 400 determines whether the frequency of the rate of change of the pedal application position with an amplitude greater than a threshold is greater than a threshold frequency after the most recent engine automatic start. If so, the answer is yes, and method 400 proceeds to 419. If not, the answer is no, and method 400 proceeds to 420. In one example, method 400 can determine the pedal change frequency and the pedal change frequency greater than a threshold amplitude by applying a Fourier transform to the pedal position signal.

[0063] At 419, method 400 indicates that the vehicle is being operated by a driver characterized as "aggressive" after the most recent engine automatic start. Method 400 proceeds to 422.

[0064] At 420, method 400 determines whether, after the most recent engine auto - start, the frequency at which a human driver switches from a driver - demand pedal to a vehicle - deceleration pedal or vice versa is greater than a threshold change rate. If so, the answer is yes, and method 400 proceeds to 421. If not, the answer is no, and method 400 proceeds to 422.

[0065] At 421, method 400 indicates that the vehicle is being operated by a human or autonomous driver characterized as "aggressive" after the most recent engine auto - start. Method 400 proceeds to 422.

[0066] At 422, method 400 determines the ratio of the actual total number of low - benefit engine starts to the actual total number of engine starts for a particular human or autonomous driver of the vehicle. The ratio can be expressed as: ATNLBES / ATNES, where ATNLBES is the actual total number of low - benefit engine starts, and ATNES is the actual total number of engine starts, where the engine starts are automatic engine starts performed based on driver demand. Method 400 proceeds to 424.

[0067] At 424, method 400 determines whether a threshold number of automatic engine starts have been performed for a particular driver and based on driver demand. If so, the answer is yes, and method 400 proceeds to 426. Otherwise, the answer is no, and method 400 proceeds to exit.

[0068] At 426, method 400 determines whether the ratio determined at 422 is greater than a threshold amount, and whether the human or autonomous driver of the vehicle has been characterized as aggressive after past engine starts based on driver - demand torque or power. If so, the answer is yes, and method 400 proceeds to 428. Otherwise, the answer is no, and method 400 proceeds to exit.

[0069] At 428, method 400 adjusts the first automatic engine - start threshold. The first automatic engine - start threshold is the threshold time amount by which driver demand exceeds a threshold before the engine can be automatically started. For example, if the initial threshold time amount by which driver demand exceeds 160 Newton - meters is 1.5 seconds, then the engine can be automatically started if the driver - demand torque exceeds 160 Newton - meters for more than 1.5 seconds. In response to satisfying the conditions at steps 424 and 426, the initial threshold time amount can be increased by a predetermined amount (e.g., 0.4 seconds), or alternatively, an amount interpolated based on vehicle operating conditions. Method 400 proceeds to 430.

[0070] At 430, method 400 adjusts the smoothing factor of the driver demand. The smoothing factor value can be increased from an initial value to a new value that increases the time response of the driver demand torque or power. For example, the initial smoothing factor value can allow the filtered driver demand torque value to reach the value of a step change in driver demand torque within 0.2 seconds. The increased smoothing factor can allow the filtered driver demand torque to reach the same step change in driver demand torque within 0.3 seconds. By adjusting the smoothing factor, or alternatively the time constant of the filter, the changes in driver demand can be attenuated such that they may have a lesser tendency to cause the engine to automatically start. Method 400 proceeds to 432.

[0071] At 432, method 400 adjusts the driver demand that is the basis for automatic engine start. In one example, method 400 adjusts the scaling of the driver demand pedal position with respect to the driver demand power or torque. Specifically, method 400 reduces the driver demand power or torque for a particular driver demand pedal position. Method 400 can adjust the driver demand power or torque for multiple driver demand pedal positions such that an increase in the driver demand pedal position results in a lesser increase in driver demand for at least a portion of the driver demand pedal range. Method 400 proceeds to 434.

[0072] At 434, method 400 adjusts a second automatic engine start threshold. The second automatic engine start threshold is the threshold amount of driver demand torque or power that must be exceeded to initiate an automatic engine start. For example, if the initial threshold amount of driver demand torque is 160 Newton - meters, the engine can initially automatically start if the driver demand torque exceeds 160 Newton - meters. In response to satisfying the conditions at steps 424 and 426, the initial threshold amount of driver demand torque or power can be increased by a predetermined amount (e.g., 20 Newton - meters), or alternatively, an amount interpolated based on the vehicle operating conditions. Method 400 proceeds to exit.

[0073] After the thresholds and parameters have been modified or adapted based on driver classification and engine start classification, the engine can be automatically started based on the newly adjusted thresholds and parameters.

[0074] In this way, method 400 can adapt the engine automatic start thresholds and parameters such that the tendency to automatically start the engine of a vehicle driven by a human vehicle driver who has been classified as "aggressive" may be less. This can improve vehicle fuel economy and reduce vehicle emissions.

[0075] Therefore, Figures 4 to 6The method provides a method for operating a vehicle, the method comprising: adjusting one or more engine automatic start thresholds in response to multiple low-benefit engine starts. In a first example, the method comprises: wherein the one or more engine automatic start thresholds include a threshold time amount that the driver demand exceeds the threshold driver demand. In a second example that may include the first example, the method comprises: wherein the threshold driver demand is included in the one or more engine automatic start thresholds. In a third example that may include one or both of the first example and the second example, the method further comprises adjusting the driver demand according to the driver demand pedal position in response to the multiple low-benefit engine starts. In a fourth example that may include one or more of the first example to the third example, the method further comprises the time constant of a filter applied to the driver demand torque or power in response to the multiple low-benefit engine starts. In a fifth example that may include one or more of the first example to the fourth example, the method comprises: wherein the low-benefit engine start includes starting the engine and stopping the engine before the engine has performed a threshold amount of work to propel the vehicle or charge the traction battery of the vehicle. In a sixth example that may include one or more of the first example to the fifth example, the method comprises: wherein the low-benefit engine start includes that the time amount that the engine runs at a torque or power greater than the threshold driver demand after the engine starts is less than the threshold time amount.

[0076] Therefore, Figures 4 to 6 The method also provides a method for operating a vehicle, the method comprising: adjusting one or more engine automatic start thresholds in response to multiple low-benefit engine starts and a behavior classification of a human vehicle driver that has been characterized as aggressive. In a first example, the method further comprises: not including engine starts not based on driver demand in the multiple low-benefit engine starts. In a second example that may include the first example, the method comprises: wherein the adjustment is based on the actual total number of low-benefit engine starts divided by the total number of engine starts or the probability of generating a low-benefit engine start determined according to previous engine starts. In a third example that may include one or both of the first example and the second example, the method comprises: wherein the multiple low-benefit engine starts are based on the human vehicle driver rather than a second human vehicle driver. In a fourth example that may include one or more of the first example to the third example, the method comprises: wherein adjusting one or more engine automatic start thresholds includes increasing the engine automatic start threshold such that the engine automatic start frequency is reduced.

[0077] It should be noted that the example control and estimation routines included herein can be used with a variety of engine and / or vehicle system configurations. The control methods and routines disclosed herein can be stored as executable instructions in a non-transitory memory and can be executed by a control system including a controller in conjunction with various sensors, actuators, and other engine hardware. The specific routines described herein can represent one or more of any number of processing strategies (such as event-driven, interrupt-driven, multi-tasking, multi-threading, etc.). Accordingly, the various actions, operations, and / or functions shown can be executed in the sequence shown, executed in parallel, or omitted in some cases. 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 actions, operations, and / or functions shown can be repeatedly executed according to the particular strategy used. Additionally, the actions, operations, and / or functions described can graphically represent code to be programmed into the non-transitory memory of a computer-readable storage medium for an engine control system, where the described actions are implemented by executing the instructions in a system including various engine hardware components in conjunction with an electronic controller.

[0078] It should be understood that the configurations and routines disclosed herein are exemplary in nature and these specific embodiments should not be considered limiting since many variations are possible. For example, the above techniques can be applied to V-6, I-4, I-6, V-12, opposed 4-cylinder, and other engine types. The subject matter of the present disclosure includes all novel and non-obvious combinations and sub-combinations of the various systems and configurations as well as other features, functions, and / or properties disclosed herein.

[0079] As used herein, unless otherwise specified, the term "about" is interpreted to mean ±5% of a range.

[0080] The appended claims particularly point out certain combinations and sub-combinations regarded as novel and non-obvious. These claims may refer to "a" element or "a first" element or the equivalent thereof. Such claims can be understood to include the incorporation of one or more such elements, neither requiring nor precluding two or more such elements. Other combinations and sub-combinations of the disclosed features, functions, elements, and / or properties can be claimed by amending the claims or by presenting new claims in this application or a related application. Such claims, whether broader, narrower, equivalent, or different in scope from the original claims, are also regarded as included within the subject matter of the present disclosure.

[0081] In one aspect of the present invention, a method for operating a vehicle includes: adjusting one or more engine auto-start thresholds in response to multiple low-benefit engine starts.

[0082] In one aspect of the present invention, the one or more engine automatic start thresholds include a threshold amount of time that a driver demand exceeds a threshold driver demand.

[0083] In one aspect of the present invention, the threshold driver demand is included in the one or more engine automatic start thresholds.

[0084] In one aspect of the present invention, the method includes adjusting the driver demand based on the driver demand pedal position in response to the multiple low-benefit engine starts.

[0085] In one aspect of the present invention, the method includes the time constant of a filter applied to the driver demand torque or power in response to the multiple low-benefit engine starts.

[0086] In one aspect of the present invention, the multiple low-benefit engine starts include starting the engine and stopping the engine before the engine has performed a threshold amount of work to propel the vehicle or charge the traction battery of the vehicle.

[0087] In one aspect of the present invention, the multiple low-benefit engine starts include the time amount that the engine runs at greater than the threshold driver demand torque or power after engine start being less than a threshold for a calibrated time amount.

[0088] According to the present invention, there is provided a vehicle system having: an electric motor; an internal combustion engine; and a controller including executable instructions that cause the controller to adjust one or more engine automatic start thresholds in response to a behavior classification that has been characterized as that of an aggressive human vehicle driver.

[0089] According to an embodiment, the behavior classification is based on a rate of change of the position of the pedal.

[0090] According to an embodiment, the behavior classification is based on a rate of change of the speed of the pedal.

[0091] According to an embodiment, the behavior classification is based on a driver demand change frequency being greater than a threshold.

[0092] According to an embodiment, the behavior classification is based on pedal movement.

[0093] According to an embodiment, one of the one or more engine automatic start thresholds is an amount of estimated work performed by the internal combustion engine.

[0094] According to an embodiment, the present invention is further characterized by additional executable instructions for starting the internal combustion engine in response to the one or more engine automatic start thresholds being exceeded.

[0095] According to an embodiment, the invention is further characterized by additional executable instructions for adjusting the one or more engine automatic start thresholds in response to multiple low-benefit engine starts.

[0096] According to the invention, a method for operating a vehicle includes: adjusting one or more engine automatic start thresholds in response to multiple low-benefit engine starts and a behavior classification of a human vehicle driver that has been characterized.

[0097] In one aspect of the invention, the method includes not including engine starts that are not based on driver demand in the multiple low-benefit engine starts.

[0098] In one aspect of the invention, the adjustment is based on the probability of performing a low-benefit engine start determined according to a previous engine start.

[0099] In one aspect of the invention, the multiple low-benefit engine starts are based on the human vehicle driver and not on a second human vehicle driver.

[0100] In one aspect of the invention, adjusting one or more engine automatic start thresholds includes increasing the engine automatic start threshold such that the engine automatic start frequency is reduced.

Claims

1. A method for operating a vehicle, comprising: One or more engine autostart thresholds are adjusted in response to a plurality of inefficient engine starts. 2 . The method of claim 1 , wherein the one or more engine auto-start thresholds include a threshold amount of time that a driver demand exceeds a threshold driver demand. 3 . The method of claim 2 , wherein the threshold driver demand is included in the one or more engine auto-start thresholds. 4 . The method of claim 1 , further comprising adjusting driver demand based on a driver demand pedal position in response to the plurality of inefficient engine starts. 5 . The method of claim 1 , further comprising a time constant of a filter applied to a driver demand torque or power in response to the plurality of inefficient engine starts. 6 . The method of claim 1 , wherein the plurality of inefficient engine starts includes starting an engine and stopping the engine before the engine has performed a threshold amount of work to propel the vehicle or charge a traction battery of the vehicle. 7 . The method of claim 1 , wherein the plurality of inefficient engine starts comprises an amount of time after an engine start where the engine is operated at greater than a threshold driver demand torque or power that is less than a threshold for a calibrated amount of time.

8. A vehicle system comprising: Motor; Internal combustion engines; as well as A controller includes executable instructions that cause the controller to adjust one or more engine auto-start thresholds in response to a behavioral classification of a human vehicle driver that has been characterized as aggressive.

9. The vehicle system of claim 8, wherein the behavior classification is based on a rate of change of position of a pedal.

10. The vehicle system of claim 8, wherein the behavior classification is based on a rate of change of speed of a pedal.

11. The vehicle system of claim 8, wherein the behavior classification is based on a driver demand change frequency being greater than a threshold.

12. The vehicle system of claim 8, wherein the behavior classification is based on pedal movement.

13. The vehicle system of claim 8, wherein one of the one or more engine auto-start thresholds is an estimated amount of work performed via the internal combustion engine.

14. The vehicle system of claim 8, further comprising additional executable instructions for starting the internal combustion engine in response to the one or more engine auto-start thresholds being exceeded. 15 . The vehicle system of claim 8 , further comprising additional executable instructions for adjusting the one or more engine auto-start thresholds in response to a plurality of inefficient engine starts.

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