System and method for power take-off control

Abstract

The present disclosure provides a system and method for power take-off control. Methods and systems are presented for operating a vehicle powertrain including a power take-off. In one non-limiting example, engine speed may be adjusted to improve engine efficiency during conditions in which the engine is operating in idle conditions over a threshold amount of time, such that fuel consumption and wear may be reduced.

Description

TECHNICAL FIELD

[0001] This specification generally relates to methods and systems for controlling a power take-off device of a vehicle. BACKGROUND ART

[0002] A vehicle may include a power take-off device that provides a way to transfer power from the vehicle's driveline to a device external to the vehicle's powertrain. The power take-off device may be included in a transmission at a location downstream of a torque converter and upstream of an output shaft of the transmission. Some vehicles, particularly commercial vehicles, may operate for extended periods at an engine idle condition due to the type of activities the vehicle is involved in. When the vehicle is operating at an idle condition, the power take-off device of the vehicle may be activated or deactivated. Additionally, the engine idle condition may be different when the vehicle's transmission is engaged in park or neutral compared to when the transmission is engaged in a forward or reverse gear. Operating the engine at idle may increase vehicle fuel consumption and shorten engine life. Therefore, it may be desirable to provide a way to operate the engine and vehicle such that vehicle fuel consumption can be reduced and engine life can be extended. SUMMARY OF THE INVENTION

[0003] The inventors herein have recognized the above problems and have developed a method for operating a powertrain of a vehicle, which includes: adjusting an engine rotational speed via a controller when a power take-off device positioned downstream of a torque converter is engaged in response to an actual total time amount of the engine being in an idle condition exceeding a threshold time amount and the engine efficiency being away from a predetermined engine efficiency by more than a threshold engine efficiency, wherein the actual total time amount of the engine being in an idle condition starts from the most recent time when the engine enters the idle condition.

[0004] By adjusting the engine speed in response to the actual total time amount of the engine being in an idle condition exceeding the threshold time amount, technical results of reducing fuel consumption and increasing engine life can be provided. Specifically, if the vehicle has idled for more than the threshold time amount, the fuel consumption of the engine can be reduced by reducing the engine speed. The lower engine speed can also reduce engine wear and extend engine life.

[0005] This specification may provide several advantages. Specifically, the method can reduce engine fuel consumption. Additionally, if the engine operates at a higher engine idle speed, the method can reduce engine wear. Further, the method can utilize previous vehicle operating conditions such that the power take-off device performance can represent vehicle operation.

[0006] The above and other advantages and features of this specification will be readily apparent from the following detailed description when understood alone or in conjunction with the accompanying drawings.

[0007] It is understood that the above invention content is provided to introduce a series of concepts further described in the detailed description in a simplified form. This does not mean identifying the key features of the claimed subject matter, and the scope of the claimed subject matter is uniquely defined by the claims attached to the detailed description. In addition, the claimed subject matter is not limited to the implementation manner that solves any disadvantages mentioned above or in any part of this disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 A schematic diagram of an engine is shown;

[0009] Figure 2 A schematic diagram of an exemplary vehicle powertrain including an engine is shown;

[0010] Figure 3 An exemplary graph showing an exemplary power output device operation sequence is shown;

[0011] Figure 4 An exemplary method for operating a vehicle is shown; and

[0012] Figure 5 A chart showing an exemplary engine fuel consumption map is shown. DETAILED DESCRIPTION

[0013] This specification relates to operating a vehicle powertrain including a power output device having a transmission. The power output device can supply mechanical power to a device external to the vehicle powertrain. If the power output device is engaged, but the driven device changes from a state of loading the power output device to a state of not loading the power output device, the operation of the engine can be automatically adjusted to save fuel. In addition, during a condition where the engine operates at an elevated idle speed for more than a threshold amount of time, the operation of the engine can be adjusted to reduce fuel consumption and engine wear. The power output device can be powered by an engine of the type shown. The power output device can be incorporated into the powertrain as shown. The power output device can operate as shown in the sequence of. The vehicle and the power output device can be operated according to the method of. The engine efficiency can be improved based on the engine fuel consumption map as shown. Figure 1 Figure 2 Figure 2 Figure 3 Figure 3 Figure 4 Figure 4 Figure 5 Figure 5

[0014] Referring to Figure 1 , an internal combustion engine 10 (which includes a plurality of cylinders, Figure 1One of the cylinders is shown, which is controlled by the electronic engine controller 12. The engine 10 includes a combustion chamber 30 and a cylinder wall 32, where a piston 36 is positioned within the cylinder wall and connected to a crankshaft 40. A flywheel 97 and a ring gear 99 are coupled to the crankshaft 40. A starter 96 (e.g., a low-voltage (operating at less than 30 volts) motor) includes a pinion shaft 98 and a pinion 95. The pinion shaft 98 enables the pinion 95 to be selectively advanced 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 chain. In one example, the starter 96 is in a basic state when not engaged to the engine crankshaft. The combustion chamber 30 is shown to be in communication 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 activated and deactivated by a valve activation device 59. The exhaust valve 54 can be selectively activated and deactivated by a valve activation device 58.

[0015] A fuel injector 66 is shown positioned to inject fuel directly into the cylinder 30, which is known as direct injection to those skilled in the art. 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.

[0016] Additionally, the intake manifold 44 is shown to be in communication with a turbocharger compressor 162 and an engine intake 42. In other examples, the compressor 162 can be a supercharger compressor. A shaft 161 mechanically couples the turbocharger turbine 164 to the turbocharger compressor 162. An optional electronic throttle 62 (e.g., a center or engine intake manifold throttle) adjusts the position of a 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 a plenum chamber 45, the pressure in the plenum 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. A compressor recirculation valve 47 can be selectively adjusted to a plurality of positions between fully open and fully closed. A wastegate 163 can be adjusted via the controller 12 to allow the exhaust to selectively bypass the turbine 164, thereby controlling the speed of the compressor 162.

[0017] The air filter 43 cleans the air entering the engine intake 42 via the inlet 3 that is exposed to ambient temperature and pressure. The converted combustion by-products are discharged at the outlet 5 that is exposed to ambient temperature and pressure. Thus, when the engine 10 rotates to suck air from the inlet 3 and discharge the combustion by-products to the outlet 5, the piston 36 and the combustion chamber 30 can operate as a pump. According to the flow direction through the engine 10, the exhaust manifold 48, and the engine intake 42, the inlet 3 is upstream of the outlet 5. Upstream does not include anything outside the engine beyond the inlet 3, and downstream does not include anything outside the engine beyond the outlet 5.

[0018] The distributorless ignition system 88 provides an ignition spark to the combustion chamber 30 via the spark plugs 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 catalytic converter.

[0020] The controller 12 is shown in Figure 1 as a conventional microcomputer that includes: 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. The controller 12 is shown receiving various signals from sensors coupled to the engine 10 in addition to the previously discussed signals, including: an engine coolant temperature (ECT) from a temperature sensor 112 coupled to the coolant jacket 114; a position sensor 134 coupled to the driver demand pedal 130 for sensing the force applied by the foot 152; a position sensor 154 coupled to the brake caliper application pedal 150 for sensing the force applied by the foot 152, a measurement of the engine manifold pressure (MAP) from a pressure sensor 123 coupled to the intake manifold 44; a measurement of the engine boost pressure or throttle inlet pressure from a pressure sensor 122; an engine position from an engine position sensor 118 sensing the position of the crankshaft 40; a measurement of the air mass entering the engine from a sensor 120; and a measurement of the throttle position from a sensor 68. Atmospheric pressure can also be sensed (sensor not shown) for processing by the controller 12. In a preferred aspect of this specification, the engine position sensor 118 generates a predetermined number of equally spaced pulses per revolution of the crankshaft, whereby the engine speed (RPM) can be determined.

[0021] 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 of the piston 36 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 bottom dead center (BDC).

[0022] During the compression stroke, 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 at which 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 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 a spark plug 92, resulting in combustion.

[0023] During the expansion stroke, the expanding gases push the piston 36 back to 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 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 can vary, such as to provide positive or negative valve overlap, late intake valve closing, or various other examples.

[0024] Now refer to Figure 2 , Figure 2 is a block diagram of a vehicle 225 including a powertrain 200. Figure 2 The powertrain of Figure 1The engine 10 shown. The engine 10 includes one or more torque actuators 204 (e.g., throttle, camshaft, fuel injector, etc.). The powertrain 200 can be powered by the engine 10. The engine crankshaft 40 is shown coupled to the impeller 285 of the torque converter 206. The torque converter impeller 285 is mechanically coupled to the transmission pump 289. The mechanically driven transmission pump 289 supplies pressurized transmission fluid to the gear clutches (e.g., gear clutches 1-10). The torque converter 206 also includes a turbine 286 coupled to the transmission input shaft 270. The transmission input shaft 270 mechanically couples the torque converter 206 to the automatic transmission 208, and its speed is monitored via the speed sensor 217. The torque converter 206 also includes a torque converter bypass lock-up clutch 212 (TCC). When the TCC is locked closed, torque is transmitted directly from the impeller 285 to the turbine 286. The TCC is electrically operated by the controller 12. Alternatively, the TCC can be hydraulically locked closed. In one example, the torque converter can be referred to as a component of the transmission. Additionally, the TCC can be partially closed, which provides an adjustable torque capacity for the TCC. The TCC provides a frictional torque path through the torque converter 206, while torque can also be transmitted between the impeller 285 and the turbine 286 via the fluid. The torque transmitted via the fluid follows the fluid torque path from the impeller 285 to the turbine 286.

[0025] When the torque converter lock-up clutch 212 is fully disengaged, the torque converter 206 transmits engine torque to the automatic transmission 208 via fluid transfer between the torque converter turbine 286 and the torque converter impeller 285, thereby achieving torque multiplication. In contrast, when the torque converter lock-up clutch 212 is fully engaged, the engine output torque is directly transmitted to the input shaft 270 of the transmission 208 via the torque converter clutch. Alternatively, the torque converter lock-up clutch 212 can be partially engaged, thereby enabling adjustment of the amount of torque directly transmitted to the transmission by adjusting the torque capacity of the TCC. The controller 12 can be configured to adjust the amount of torque transmitted by the torque converter 212 by responding to various engine operating conditions or adjusting the torque converter lock-up clutch applied pressure or force according to a driver-based engine operation request.

[0026] The automatic transmission 208 includes a gear clutch 211 and a forward clutch 210 to engage or disengage the engaged gear 209 (e.g., reverse gear and gears 1-10). The gear clutch 211 (e.g., 1-10) and the forward clutch 210 can be selectively engaged to propel the vehicle. The transmission 208 is configured such that one of the gears 209 can be engaged by applying two or more of the clutches 211. In other words, when two or more of the clutches 211 are closed, a gear can surely be engaged. Further, when one or more of the clutches 211 are disengaged but one or more of the clutches 211 are simultaneously closed, the transmission 208 can enter a neutral state where the input shaft 270 is not engaged or coupled to the output shaft 260. The torque output from the automatic transmission 208 can be transmitted to the wheels 216 via the output shaft 260 to propel the vehicle. The speed of the output shaft 260 is monitored via the speed sensor 219. Specifically, the automatic transmission 208 can transfer the input drive torque at the input shaft 270 in response to the vehicle driving conditions before transmitting the output drive torque to the wheels 216.

[0027] Further, frictional force can be applied to the wheels 216 by engaging the wheel brake calipers 218. In one example, the wheel brake calipers 218 can be engaged in response to the driver pressing their foot on the brake caliper pedal as Figure 1 shown. In other examples, the controller 12 or a controller connected to the controller 12 can engage the wheel brake calipers. Similarly, the frictional force applied to the wheels 216 can be reduced by disengaging the wheel brake calipers 218 in response to the driver releasing their foot from the brake caliper pedal. Further, the vehicle brake calipers can apply frictional force to the wheels 216 via the controller 12 as part of an automated engine stop procedure.

[0028] The automatic transmission 208 also includes a power take-off device 238 (e.g., an accessory drive) that extracts power from the automatic transmission 208 to power on-vehicle accessories. The accessories can include, but are not limited to, an alternator 231, an air-conditioning compressor 230, a pump 233 (e.g., an air pump, a vacuum pump, etc.), and a power steering pump 232. The alternator 231 can supply power to power-consuming devices 234 (e.g., a battery, lights, sensors, actuators). In one example, the power take-off device 238 consists of one or more gears such that if the TCC is open, the accessories can be driven at a multiple of the vehicle speed rather than a multiple of the engine speed. The power take-off device 238 can be mechanically coupled to the turbine 286, the input shaft 270, or another transmission component that is mechanically coupled to the input shaft 270. The power take-off clutch 239 can be opened to disconnect the accessories (e.g., 230 - 234) from the transmission input shaft 270. The power take-off clutch 239 can be closed to couple the accessories (e.g., 230 - 234) to the transmission input shaft 270. The power take-off device 238 can provide output via a pulley or gears and a mechanical linkage 235 (such as a belt or gears).

[0029] Thus, the engine 10 can be the only adjustable torque source that provides positive torque to the powertrain 200. Alternatively, the powertrain can include the engine 10 and optionally a motor / generator (not shown). Torque flows from the engine 10 to the transmission 208 before being applied to the wheels 216. Thus, the engine 10 is upstream of the torque converter 206, the transmission 208, and the wheels 216 in the torque flow direction. Additionally, the torque converter 206 is upstream of the forward clutch 210 and the gear clutch 211.

[0030] The controller 12 can be configured to receive inputs from the engine 10 (as shown in more detail in Figure 1 ), and accordingly control the torque output of the engine and / or the operation of the torque converter, the transmission, the clutches, and / or the wheel brake calipers. Additionally, the controller 12 can receive driver inputs from the human / machine interface 299. In some examples, the human / machine interface 299 can provide powertrain information and indications to the driver. In the case of a diesel engine, the controller 12 can control the engine torque output by controlling a combination of fuel pulse width, fuel pulse timing, and air charge. In all cases, engine control can be performed cylinder-by-cylinder to control the engine torque output.

[0031] The controller 12 can also supply vehicle data (e.g., engine operating conditions, idle time, etc.) to a remote server 298 via a cellular network (not shown) or a satellite (not shown). The controller 12 can also receive data and commands from the remote server 298.

[0032] Figure 1 and Figure 2 The system of Figure 2 provides a vehicle system that includes: an engine; a transmission that includes a torque converter and a power take-off device positioned downstream of the torque converter and upstream of the transmission output shaft; and a controller that includes executable instructions stored in a non-transitory memory, the executable instructions causing the controller to adjust the rotational speed of the engine when the actual total amount of time the engine operates in an idle condition exceeds a threshold amount of time and it is determined that the power take-off device is not in use, where the actual total amount of time the engine operates in an idle condition begins at the time the engine most recently entered the idle condition. In a first example, the vehicle system includes where it is determined that the power take-off device is not in use based on the engine load being less than a threshold load. In a second example that may include the first example, the vehicle system includes where the rotational speed of the engine is adjusted to a lower rotational speed. In a third example that may include one or both of the first example and the second example, the vehicle system further includes additional instructions that cause the controller to adjust the rotational speed of the engine when the actual total amount of time the engine operates in an idle condition exceeds a threshold amount of time and it is determined that the power take-off device is in use, where the actual total amount of time the engine operates in an idle condition begins at the time the engine most recently entered the idle condition. In a fourth example that may include one or more of the first example through the third example, the vehicle system further includes additional executable instructions that cause the controller to adjust the amount of time it takes to adjust the rotational speed of the engine from a first rotational speed to a second rotational speed in response to a change in engine load. The vehicle system of claim 12, further includes additional executable instructions that cause the controller to adjust the amount of time it takes for the controller to determine the average engine power or engine load based on engine power or engine load. In a fifth example that may include one or more of the first example through the fourth example, the vehicle system further includes additional executable instructions that cause the controller to compare the current engine efficiency to a predetermined engine efficiency as a basis for adjusting the rotational speed of the engine. In a sixth example that may include one or more of the first example through the fifth example, the vehicle system includes where adjusting the rotational speed of the engine includes one of the following: increasing the rotational speed of the engine, decreasing the rotational speed of the engine, or maintaining the rotational speed of the engine.

[0033] Now referring to Figure 3 , a graph showing a predictive vehicle power take-off device operation sequence is shown. Figure 3The curves are aligned in time. It can be based on Figure 4 The method passes through Figure 1 and Figure 2 The system to provide this sequence. The vertical marks t0 to t2 represent the times of particular interest in the sequence.

[0034] Starting from the Figure 3 top of, the first curve is a graph of the power take-off (PTO) operating state versus time. The vertical axis represents the PTO operating state, and when the trace 302 is at a high level near the vertical axis arrow, the PTO is active and engaged (e.g., the driveline is mechanically coupled to the accessory because, for example, the PTO clutch is closed). When the trace 302 is at a low level near the vertical axis arrow, the PTO is not activated (e.g., the driveline is not mechanically coupled to the accessory because, for example, the PTO clutch is open). The horizontal axis represents time, and time increases from the Figure 3 left side of Figure 3 to the

[0035] right side of. Figure 3 Starting from the Figure 3 top of, the second curve is a graph of the automatic PTO adjustment state versus time. The vertical axis represents the automatic PTO adjustment state, and when the trace 304 is at a relatively high level near the vertical axis arrow, the operation of the PTO can be adjusted via the controller. When the trace 304 is at a relatively low level near the horizontal axis, the operation of the PTO cannot be automatically adjusted. The horizontal axis represents time, and time increases from the Figure 3 left side of

[0036] to the Figure 3 right side of. Figure 3 Starting from the Figure 3 top of, the third curve is a graph of the engine speed (e.g., engine rotational speed) versus time. The vertical axis represents the engine speed, and the engine speed increases in the direction of the vertical axis arrow. The horizontal axis represents time, and time increases from the

[0037] left side of Figure 3 to the Figure 3 left side of Figure 3 right side of.

[0038] At time t0, the power takeoff is engaged and the engine is at idle speed. The automatic power takeoff is activated so that the controller can automatically adjust vehicle operation in response to power takeoff operating conditions. The engine speed is at an elevated idle speed.

[0039] At time t1, the engine has been at the elevated idle speed for more than a threshold amount of time, so the controller automatically adjusts the engine speed to reduce fuel consumption and engine wear. In this example, the engine speed is decreased. In other examples, if increasing the engine speed improves engine efficiency, the engine speed can be increased.

[0040] At time t2, the vehicle operator deactivates the automatic power takeoff adjustment. Thus, the controller reverts to the power takeoff operating condition that has been manually input or is the baseline power takeoff operating condition. In this example, the manually input power takeoff engine speed is slightly increased. The power takeoff remains engaged and the engine remains at idle speed.

[0041] In this way, vehicle operating conditions can be adjusted when the engine is at idle and the power takeoff is engaged. Automatic control can reduce engine fuel consumption and engine wear. Manual control can allow the user to operate the vehicle in a specific manner based on conditions that the controller may not know (e.g., requirements of a device mechanically coupled to the powertrain via the power takeoff).

[0042] Now referring to Figure 4 , a method for operating a vehicle including a power takeoff is shown. Figure 4 The method of Figure 1 and Figure 2 can be applied to the powertrain shown in Figure 4 . Additionally, at least part of the method of Figure 1 and Figure 2 can be included as executable instructions stored in one or more controllers of a system (e.g., the system of Figure 4 ). Further, at least part of the method of

[0043] can be actions taken in the physical world to transform the state of a device.

[0044] At 403, method 400 continues vehicle operation based on the current operating condition of the vehicle. Method 400 proceeds to exit.

[0045] At 404, method 400 monitors the actual total amount of time the engine has been continuously in an idle operating condition since the most recent time the engine entered an idle condition. Method 400 also monitors the actual total amount of time the engine has been continuously in a raised idle (e.g., where the engine operates at a rotational speed greater than a threshold speed while idling) operating condition since the most recent time the engine entered a raised idle condition. Additionally, method 400 monitors the actual total amount of time the engine has been continuously in a raised idle operating condition with the power output device activated since the most recent time the engine entered a raised idle condition. Method 400 can also determine the actual total amount of time the engine has been continuously idling divided by the actual total amount of time the engine has been operating since the most recent engine start, starting from the most recent time the engine entered an idle condition. Additionally, method 400 can also determine the actual total amount of time the engine has been continuously operating at a raised idle divided by the actual total amount of time the engine has been operating since the most recent engine start, starting from the most recent time the engine entered a raised idle condition. In some examples, method 400 can determine the actual total amount of time the engine has been operating at a raised idle speed since the most recent time the engine entered a raised idle speed condition without activating the power output device. Method 400 can determine these conditions via a timer in the controller and engine operating conditions (e.g., engine load, engine speed, vehicle speed, etc.).

[0046] Method 400 can transmit these and other operating conditions to an external server or cloud via satellite, wifi, or cellular network. Additionally, based on these operating conditions, the controller or external server can schedule the vehicle for an oil change and other maintenance. Additionally, the previously determined conditions and / or parameters can be determined for a specific time interval (e.g., 4 hours) and / or the entire life of the vehicle. Method 400 proceeds to 406.

[0047] At 406, method 400 determines whether the actual total amount of time the vehicle has been in a raised idle condition since the most recent time the vehicle entered a raised idle condition or since a different time or condition exceeds a threshold amount of time. If so, the answer is yes, and method 400 proceeds to 408. Otherwise, the answer is no, and method 400 proceeds to 407. In this way, method 400 determines that the engine has been in uninterrupted idle (e.g., has not exited idle) for a threshold amount of time, and then proceeds to step 408.

[0048] When the engine load is less than a threshold engine load (e.g., 0.06 engine load), method 400 may determine that the engine is in an idle condition and that the vehicle speed is zero when the power takeoff is not engaged (e.g., the power takeoff clutch is fully open). Additionally, when the engine load is less than a second threshold engine load (e.g., 0.07 engine load), method 400 may determine that the engine is in an idle condition and that the vehicle speed is zero when the power takeoff is engaged (e.g., the power takeoff clutch is fully closed).

[0049] At 407, method 400 maintains the engine at its current operating condition (e.g., speed and load). Alternatively, if the engine transitions from a non-idle condition to an idle condition, method 400 may operate the engine at a base idle condition. Method 400 proceeds to exit.

[0050] At 408, method 400 adjusts the time period T for averaging the engine power output or alternatively or additionally the engine load to determine the average engine power. In one example, the time period for determining the average engine power output or engine load is based on an estimated power takeoff load. For example, for a larger power takeoff load (e.g., greater than or equal to 10 kilowatts), the time period for averaging the engine load or engine power may be smaller (e.g., between 5 seconds and 10 seconds). For a smaller power takeoff load (e.g., less than 10 kilowatts), the time period for averaging the engine load or engine power may be larger (e.g., between 60 seconds and 120 seconds). After determining the time period (T) for which to average the engine power and / or load, method 400 proceeds to 410.

[0051] At 410, method 400 determines the time-averaged power amount generated by the engine at the current engine operating condition. Method 400 may generate the time-averaged power generated by the engine via the following equation:

[0052]

[0053] where Peng is the engine power, n is the actual total number of engine torque and engine speed data samples within a predetermined time interval (e.g., T), Teng is the engine torque, Neng is the engine speed, and i is the number of samples within a predetermined time interval (e.g., 10 seconds). Thus, if the controller has a sampling rate of one hundred samples per second and the predetermined time interval is 10 seconds, then n will be 1000. Method 400 may adjust the predetermined time interval T as described below, and the controller may sample the engine operating condition at a predetermined interval (e.g., every 10 millisecond interval).

[0054] Method 400 may determine the average engine load value via the following equation:

[0055]

[0056] Where Leng is the engine load, and n is the actual total number of engine torque and engine speed data samples within a predetermined time interval (e.g., T). Method 400 proceeds to 412.

[0057] At 412, method 400 adjusts the amount of time (T 输出 ) that method 400 takes to change the engine and power output device from a first engine and power output device operating condition to a second engine and power output device operating condition. In one example, the amount of time that method 400 takes to change the engine and power output device from a first engine and power output device operating condition to a second engine and power output device operating condition can be adjusted in response to historical engine and power output device operation. For example, method 400 can determine T based on the ratio of the total amount of time that the engine operates at an elevated idle speed without power output device use during the life of the vehicle to the total amount of time that the engine operates at the elevated idle speed with power output device use during the life of the vehicle. 输出 In other examples, method 400 can determine T based on one or more of the monitored conditions described at 404. 输出 Method 400 proceeds to 414.

[0058] At 414, method 400 determines whether the power output device is in use. In one example, method 400 can determine whether the power output device is in use based on a comparison of the engine load at the current engine rotational speed to the engine load at the current engine rotational speed and the minimum power output device load. When determining whether the power output device is in use, the power output device can be engaged (e.g., the power output device clutch is fully closed). For example, if the engine load at 2000 RPM engine speed in the current operating condition is 0.05 and the engine load at 2000 RPM engine speed with the minimum power output device load is 0.09, then method 400 can determine that the power output device is in use when the engine load is equal to or greater than 0.09 load at 2000 RPM engine speed. This method can have the advantage of adjusting engine operation based on the magnitude of the power output device load, which can indicate how the power output device can operate after adjustment.

[0059] In other examples, method 400 may determine whether the power take-off is in use based on the operating state of the power take-off clutch rather than the engine load. For example, if the power take-off clutch is fully closed, method 400 may determine that the power take-off is in use. If the power take-off clutch is fully open, method 400 may determine that the power take-off is not in use. This method may have the advantage of adjusting the engine operation based on the actual power take-off state, which can ensure that the engine adjustment is indeed based on the power take-off state. If method 400 determines that the power take-off is in use, then the answer is yes, and method 400 proceeds to 416. Otherwise, the answer is no, and method 400 proceeds to 430.

[0060] At 430, method 400 reduces the elevated engine idle speed by a predetermined engine speed reduction amount (e.g., 50 revolutions per minute). The elevated engine idle speed is an engine idle speed that is greater than the baseline engine idle speed. For example, for an engine, the baseline engine idle speed may be 650 revolutions per minute, while the elevated engine idle speed of the same engine may be 1200 revolutions per minute. Method 400 proceeds to 432.

[0061] At 432, method 400 determines whether the current engine rotational speed is less than a threshold rotational speed. If so, then the answer is yes, and method 400 proceeds to 436. If not, then the answer is no, and method 400 returns to 414.

[0062] At 436, method 400 maintains the current idle speed of the engine or alternatively deactivates the engine by stopping fuel supply to the engine. During a condition where the controller has not been granted permission to deactivate the engine, the engine idle speed may be maintained at a lower idle speed. The engine may be deactivated when there may be a long period of engine idling without the power take-off being engaged or in use. The engine idle speed may be maintained when there is a short period of engine idling without the power take-off being engaged or in use or if the controller has not been granted permission to deactivate the engine. Method 400 proceeds to exit.

[0063] At 416, method 400 determines whether the engine idle speed is an engine speed that is more than a threshold amount away from the requested or target engine idle speed. For example, if the target engine speed is 1000 revolutions per minute and the threshold engine speed is 50 revolutions per minute, then if the current engine speed is greater than 1050 revolutions per minute or less than 950 revolutions per minute, method 400 may determine that the engine idle speed is an engine speed that is more than a threshold amount away from the 1000 - revolution - per - minute target engine speed.

[0064] Alternatively, method 400 can determine whether the engine efficiency is away from the requested or target engine efficiency by more than a threshold engine efficiency. The efficiency of the engine or another variable indicative of engine efficiency (e.g., engine fuel consumption divided by the generated engine power) can be mapped as a function of engine speed and engine load. For example, if the target engine efficiency speed is 10% and the threshold engine efficiency is 2% at an engine load of 0.2, then if the current engine efficiency is less than 8%, method 400 can determine that the engine efficiency is away from the 10% target engine efficiency by more than the threshold amount. If method 400 determines that the engine idle speed is away from the requested or target engine idle speed by more than a threshold amount of engine speed, or if method 400 determines that the engine efficiency is away from the requested or target engine efficiency by more than the threshold engine efficiency, then the answer is yes and method 400 proceeds to 418. Otherwise, the answer is no and method 400 proceeds to 417.

[0065] At 417, method 400 maintains the current engine idle speed. The current engine idle speed can be maintained by maintaining the current engine air flow rate, the current engine fuel flow rate, and the current spark timing. Method 400 proceeds to exit.

[0066] At 418, method 400 determines whether automatic adjustment of engine operation to meet engine fuel economy and engine degradation metrics is allowed. If automatic adjustment of engine operation is allowed, then the answer is yes and method 400 proceeds to 419. If automatic adjustment of engine operation is not allowed, then the answer is no and method 400 proceeds to 420.

[0067] At 419, method 400 maintains, increases, or decreases the engine speed to maintain or increase the engine efficiency. In one example, method 400 can adjust the engine speed according to an engine efficiency map or a map representing engine fuel efficiency (e.g., a map relating engine fuel consumption divided by the generated engine power to engine speed and engine load). For example, if the engine is currently operating at 10% efficiency at 1200 revolutions per minute and the engine efficiency can be increased to 10.5% by reducing the engine speed to 1000 revolutions per minute, then method 400 reduces the engine speed. For example, the engine speed can be adjusted by increasing / decreasing the engine air flow or increasing / decreasing the spark timing. In some examples, the engine speed can be adjusted by increasing / decreasing the fuel injection timing.

[0068] In another example, method 400 adjusts the engine speed based on an engine fuel consumption map. For example, if the engine is currently operating at 1200 revolutions per minute with a fuel consumption of 6 liters per hour and the engine fuel consumption can be reduced to 5.5 liters per hour by reducing the engine speed to 1000 revolutions per minute, then method 400 reduces the engine speed. For example, the engine speed can be adjusted by increasing / decreasing the engine air flow or increasing / decreasing the spark timing. In some examples, the engine speed can be adjusted via increasing / decreasing the fuel injection timing.

[0069] Method 400 can cause the engine speed to change from a first engine speed to a second engine speed at a rate determined at 412. Method 400 proceeds to exit.

[0070] At 420, method 400 performs a manual override of the current engine operating condition. Thus, if the engine speed is currently 1400 revolutions per minute and the user inputs a manual engine speed of 1350 revolutions per minute, the controller adjusts the engine speed to 1350 revolutions per minute. For example, the engine speed can be adjusted by increasing / decreasing the engine air flow or increasing / decreasing the spark timing. In some examples, the engine speed can be adjusted via increasing / decreasing the fuel injection timing.

[0071] In this way, when the power output device is activated or deactivated, the engine operation at idle can be adjusted to improve engine fuel economy. Additionally, the rate at which the engine speed changes from a first engine speed to a second engine speed can be adjusted to meet performance and fuel economy goals. Similarly, the average of the engine power and engine load can be adjusted to increase engine and / or power output device performance metrics.

[0072] Figure 5The method provides a method for operating a vehicle's powertrain, which includes: when the actual total time amount in response to the engine being in an idle condition exceeds a threshold time amount and the engine efficiency deviates from a predetermined engine efficiency by more than a threshold engine efficiency while engaging a power output device positioned downstream of the torque converter, adjusting the engine rotational speed via a controller, wherein the actual total time amount of the engine being in an idle condition starts from the most recent time when the engine enters the idle condition. In a first example, the method includes that adjusting the engine rotational speed includes increasing the engine rotational speed. In a second example that may include the first example, the method includes that adjusting the engine rotational speed includes decreasing the engine rotational speed. In a third example that may include one or both of the first example and the second example, the method further includes adjusting the time amount spent on adjusting the engine rotational speed from a first engine rotational speed to a second engine rotational speed in response to historical engine operation data. In a fourth example that may include one or more of the first example to the third example, the method includes that the historical engine operation data includes the time amount of operating at a first elevated engine idle speed without using the power output device to the time amount of operating at a second elevated engine idle speed when using the power output device. In a fifth example that may include one or more of the first method to the fourth method, the method includes that adjusting the engine rotational speed includes adjusting the engine rotational speed to a rotational speed that increases engine efficiency. In a sixth example that may include one or more of the first example to the fifth example, the method further includes determining the time-averaged engine power in response to operating the engine at an elevated idle rotational speed for more than a threshold time amount.

[0073] Figure 4 The method also provides a method for operating a vehicle's powertrain, the method including: in response to the current engine efficiency, an assessment of whether the power output device is operating an external device, and the engine being in an uninterrupted idle condition for more than a predetermined time amount, adjusting the operation of the engine via a controller. In a first example, the method includes that the assessment of whether the power output device is operating an external device is based on the engine load. In a second example that may include the first example, the method includes that adjusting the operation of the engine includes one of the following: increasing the engine speed, decreasing the engine speed, or maintaining the engine speed. In a third example that may include one or both of the first example and the second example, the method further includes additional instructions for further adjusting the operation of the engine in response to the engine efficiency. In a fourth example that may include one or more of the first example to the third example, the method further includes additional instructions for performing the following operation: monitoring the actual total time amount of the engine operating in the idle condition since the engine most recently entered the idle condition.

[0074] Referring now to Figure 5 , an exemplary predictive map of engine fuel consumption is shown. When the engine and the power output device are under automatic control, the engine fuel consumption map can be a basis for determining the target or desired engine speed. Similar maps can be generated using engine speed and engine load or engine speed and engine efficiency reference variables to determine whether engine fuel consumption can be increased or decreased by increasing or decreasing the engine speed.

[0075] The engine fuel consumption map 500 includes rows 530 - 542 and columns 502 - 518. The second through seventh rows 532 - 542 in the first column 502 store engine rotational speed values. The second through tenth columns 504 - 518 in the first row 530 store engine torque values. The second through tenth columns 504 - 518 and their associated rows 532 - 542 store engine fuel consumption values in grams per second.

[0076] A controller (e.g., Figure 1 element 12 therein) can read the values in the map and determine whether adjusting the engine speed can increase or decrease engine fuel consumption such that fuel consumption can be reduced. For example, if the engine generates 35 Newton - meters of torque at 1000 RPM (e.g., the map cell at column 504 and row 534), the controller can determine that engine fuel efficiency can be increased by reducing the engine speed because the engine fuel consumption in the map cell at column 504 and row 532 is lower compared to the engine fuel consumption value at column 504 and row 534. Thus, the map 500 or a similar map can be a basis for adjusting the engine speed to increase or decrease fuel consumption.

[0077] This specification ends here. Without departing from the spirit and scope of this specification, many variations and modifications will occur to those skilled in the art after reading this specification. For example, single - cylinder, I2, I3, I4, I5, V6, V8, V10, V12, and V16 engines operating on natural gas, gasoline, diesel, or alternative fuels can benefit from this specification.

[0078] According to the present invention, a method for operating a powertrain of a vehicle includes: adjusting an engine rotational speed via a controller when a power output device positioned downstream of a torque converter is engaged in response to an actual total time amount that the engine is in an idle condition exceeding a threshold time amount and the engine efficiency deviating from a predetermined engine efficiency by more than a threshold engine efficiency, wherein the actual total time amount that the engine is in idle starts from the most recent time the engine enters the idle condition.

[0079] In one aspect of the present invention, adjusting the engine rotational speed includes increasing the engine rotational speed.

[0080] In one aspect of the present invention, adjusting the engine rotational speed includes decreasing the engine rotational speed.

[0081] In one aspect of the present invention, the method includes adjusting a first amount of time taken to adjust the engine rotational speed from a first engine rotational speed to a second engine rotational speed in response to historical engine operation data.

[0082] In one aspect of the present invention, the historical engine operation data includes a second amount of time of operating at a first elevated engine idle speed without using a power take-off device to an amount of time of operating at a second elevated engine idle speed while using the power take-off device.

[0083] In one aspect of the present invention, adjusting the engine rotational speed includes adjusting the engine rotational speed to a rotational speed that increases engine efficiency.

[0084] In one aspect of the present invention, the method includes determining a time-averaged engine power in response to operating the engine at an elevated idle rotational speed for more than the threshold amount of time.

[0085] According to the present invention, there is provided a vehicle system having: an engine; a transmission including a torque converter and a power take-off device, the power take-off device being positioned downstream of the torque converter and upstream of a transmission output shaft; and a controller including executable instructions stored in a non-transitory memory, the executable instructions causing the controller to adjust the rotational speed of the engine when the power take-off device is engaged and it is determined that the power take-off device is not in use in response to an actual total amount of time that the engine operates in an idle condition exceeding a threshold amount of time, wherein the actual total amount of time that the engine operates in the idle condition starts at the time when the engine most recently enters the idle condition.

[0086] According to an embodiment, it is determined that the power take-off device is not in use based on the engine load being less than a threshold load.

[0087] According to an embodiment, the rotational speed of the engine is adjusted to a lower rotational speed.

[0088] According to an embodiment, the invention is further characterized by additional instructions that cause the controller to engage the power output device and determine to adjust the rotational speed of the engine when using the power output device in response to a second actual total time amount of the engine operating in an idle condition exceeding the threshold time amount, wherein the second actual total time amount of the engine operating in the idle condition starts at the time when the engine most recently entered the idle condition.

[0089] According to an embodiment, the invention is further characterized by additional executable instructions that cause the controller to adjust the time amount taken to adjust the rotational speed of the engine from a first rotational speed to a second rotational speed in response to a change in engine load.

[0090] According to an embodiment, the invention is further characterized by additional executable instructions that cause the controller to adjust a second time amount taken by the controller to determine the average engine power or engine load based on engine power or engine load.

[0091] According to an embodiment, the invention is further characterized by additional executable instructions that cause the controller to compare the current engine efficiency with a predetermined engine efficiency as a basis for adjusting the rotational speed of the engine.

[0092] According to an embodiment, adjusting the rotational speed of the engine includes one of the following: increasing the rotational speed of the engine, decreasing the rotational speed of the engine, or maintaining the rotational speed of the engine.

[0093] According to the invention, a method for operating a powertrain of a vehicle includes: adjusting the operation of the engine via a controller in response to the current engine efficiency, an assessment of whether the power output device is operating an external device, and the engine being in an uninterrupted idle condition for more than a predetermined time amount.

[0094] In one aspect of the invention, the assessment of whether the power output device is operating an external device is based on engine load.

[0095] In one aspect of the invention, adjusting the operation of the engine includes one of the following: increasing the engine speed, decreasing the engine speed, or maintaining the engine speed.

[0096] In one aspect of the invention, the method includes additional instructions for further adjusting the operation of the engine in response to engine efficiency.

[0097] In one aspect of the present invention, the method includes additional instructions for performing the following operation: monitoring the actual total amount of time that the engine has been operating in an idle condition since the engine most recently entered the idle condition.

Claims

1. A method for operating a powertrain of a vehicle, comprising: When the actual total time amount in response to the engine being in an idle condition exceeds a threshold time amount and the engine efficiency deviates from a predetermined engine efficiency by more than a threshold engine efficiency while engaging a power take-off device positioned downstream of a torque converter, adjusting an engine rotational speed via a controller, wherein the actual total time amount of the engine being in an idle condition starts from the most recent time when the engine enters the idle condition.

2. The method according to claim 1, wherein adjusting the engine rotational speed includes increasing the engine rotational speed.

3. The method according to claim 1, wherein adjusting the engine rotational speed includes decreasing the engine rotational speed.

4. The method according to claim 1, further comprising adjusting a first time amount taken to adjust the engine rotational speed from a first engine rotational speed to a second engine rotational speed in response to historical engine operation data.

5. The method according to claim 4, wherein the historical engine operation data includes a second time amount of operating at a first elevated engine idle speed without using the power take-off device to a time amount of operating at a second elevated engine idle speed while using the power take-off device.

6. The method according to claim 5, wherein adjusting the engine rotational speed includes adjusting the engine rotational speed to a rotational speed that increases engine efficiency.

7. The method according to claim 1, further comprising determining a time-averaged engine power in response to operating the engine at an elevated idle rotational speed for more than the threshold time amount.

8. A vehicle system, comprising: An engine; A transmission including a torque converter and a power take-off device, the power take-off device being positioned downstream of the torque converter and upstream of a transmission output shaft; And A controller including executable instructions stored in a non-transitory memory, the executable instructions causing the controller to adjust the rotational speed of the engine when engaging the power take-off device in response to the actual total time amount of the engine operating in an idle condition exceeding a threshold time amount and determining that the power take-off device is not in use, wherein the actual total time amount of the engine operating in an idle condition starts from the time when the engine most recently enters the idle condition.

9. The vehicle system according to claim 8, wherein it is determined that the power take-off device is not in use based on the engine load being less than a threshold load.

10. The vehicle system according to claim 9, wherein the rotational speed of the engine is adjusted to a lower rotational speed.

11. The vehicle system according to claim 10, further comprising additional instructions that cause the controller to adjust the rotational speed of the engine when engaging the power take-off device in response to a second actual total time amount of the engine operating in an idle condition exceeding the threshold time amount and determining that the power take-off device is in use, wherein the second actual total time amount of the engine operating in an idle condition starts from the time when the engine most recently enters the idle condition.

12. The vehicle system according to claim 8, further comprising additional executable instructions that cause the controller to adjust the amount of time taken to adjust the rotational speed of the engine from a first rotational speed to a second rotational speed in response to a change in engine load.

13. The vehicle system according to claim 12, further comprising additional executable instructions that cause the controller to adjust a second amount of time taken by the controller to determine an average engine power or engine load based on engine power or engine load.

14. The vehicle system according to claim 13, further comprising additional executable instructions that cause the controller to compare a current engine efficiency with a predetermined engine efficiency as a basis for adjusting the rotational speed of the engine.

15. The vehicle system according to claim 8, wherein adjusting the rotational speed of the engine comprises one of the following: increasing the rotational speed of the engine, decreasing the rotational speed of the engine, or maintaining the rotational speed of the engine.

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