Driver torque request systems and methods

[0067] The following description is merely exemplary in nature, and is in no way intended to limit the present disclosure, its application or uses. For clarity, the same reference numbers are used in the drawings to indicate similar elements. As used herein, at least one of the phrases A, B, and C should be understood to mean logical (A or B or C), using a non-exclusive logical OR. It should be understood that the steps in the method can be executed in a different order without changing the principle of the present disclosure.

[0068] As used herein, the term module refers to application-specific integrated circuits (ASICs), electronic circuits, processors (shared, dedicated, or grouped) that execute one or more software or firmware programs, and memories, combinational logic circuits, and/ Or other suitable components that provide the required functions.

[0069] The control module of the vehicle can control the torque output of the engine based on the final driver's axle torque request. The final driver axle torque request belongs to the axle torque domain, which means that the final driver axle torque request refers to the torque at one or more wheels or axles of the vehicle. The final driver's axle torque request may be determined using one or more calculations, transformations, limits, selections, and/or other suitable calculations.

[0070] For example only, the pedal torque request may be determined based on accelerator pedal position, zero pedal torque, and other parameters. Compared with the final driver's axle torque request, the pedal torque request belongs to the propulsion torque domain. The pedal torque request can be converted into the axle torque domain, which is determined by the driver's torque request, and formed into the final driver's axle torque request.

[0071] The control module of the present disclosure limits the final driver's axle torque request to the minimum drivable axle torque. The control module can change the minimum drivability axle torque to prevent engine stall and reduce fuel consumption. The driveable axle torque that limits the final driver's axle torque request to a minimum can prevent the engine from stalling by ensuring that there is enough torque transfer capacity in the transmission to drive the engine to rotate. The driveable axle torque that limits the final driver's axle torque request to a minimum can reduce fuel consumption by allowing the control module to enter the deceleration fuel cut-off (DFCO) mode as early as possible. The driveable axle torque that limits the final driver's axle torque request to a minimum may additionally or alternatively reduce fuel consumption by allowing the control module to perform regenerative braking as early as possible.

[0072] Reference now figure 1 , A functional block diagram of an exemplary engine system 100 is shown. The engine system 100 includes an engine 102 that combusts an air/fuel mixture based on driver input from a driver input module 104 to generate driving torque for the vehicle. For example, driver input may include one or more APPs measured by an accelerator pedal position (APP) sensor (not shown), one or more BPPs measured by a brake pedal position (BPP) sensor (not shown), and cruise control The cruise torque request provided by the system (not shown). In various embodiments, the cruise control system may include an adaptive cruise control system that maintains a predetermined following distance. Driver input may also include parking, reverse gear, neutral gear, the position of the drive lever (PRNDL), and other appropriate inputs.

[0073] The air is drawn into the intake manifold 110 through the throttle valve 112. For example only, the throttle valve 112 may include a butterfly valve having a rotatable blade. The engine control module (ECM) 114 controls the throttle valve actuator module 116, and the throttle valve actuator module 116 adjusts the opening degree of the throttle valve 112 to control the amount of air drawn into the intake manifold 110.

[0074] Air from the intake manifold 110 is drawn into one or more cylinders of the engine 102. Although the engine 102 may include more than one cylinder, for illustration purposes, only one representative cylinder 118 is shown. For example only, the engine 102 may include 2, 3, 4, 5, 6, 8, 10, and/or 12 cylinders. The ECM 114 may instruct the cylinder actuator module 120 to selectively deactivate some or all of the cylinders, which may improve fuel economy in some cases.

[0075] The engine 102 may be operated using a four-stroke engine cycle. The four strokes described below may be referred to as intake stroke, compression stroke, combustion stroke, and exhaust stroke. During each rotation of the crankshaft (not shown), two of the four strokes occur within the cylinder 118. Therefore, two crankshaft revolutions are required for the cylinder 118 to experience all 4 strokes of an engine cycle.

[0076] During the intake stroke, air from the intake manifold 110 is drawn into the cylinder 118 through the intake valve 122. The ECM 114 controls a fuel actuator module 124 that adjusts the injection of fuel to achieve the desired air/fuel ratio. The fuel may be injected into the intake manifold 110 at a central location or multiple locations, such as near the intake valve of each cylinder. In various embodiments (not shown), fuel may be injected directly into the cylinder or into a mixing chamber associated with the cylinder. The fuel actuator module 124 may stop fuel injection to cylinders that are deactivated.

[0077] The injected fuel mixes with air and creates an air/fuel mixture. During the compression stroke, a piston (not shown) in the cylinder 118 compresses the air/fuel mixture. Based on the signal from the ECM 114, the spark actuator module 126 energizes the spark plug 128 in the cylinder 118, which ignites the air/fuel mixture. The timing of the spark can be specified relative to the time when the piston is at its highest position (called top dead center (TDC)).

[0078] The spark actuator module 126 may be controlled by a timing signal indicating how far before or after TDC to generate the spark. Because piston position is directly related to crankshaft rotation, the operation of the spark actuator module 126 can be synchronized with crankshaft angle. In various implementations, the spark actuator module 126 may stop supplying spark to deactivated cylinders.

[0079] The combustion of the air/fuel mixture in the cylinder may be referred to as an ignition event. The spark actuator module 126 can change the spark timing for each ignition event. In addition, the spark actuator module 126 can change the spark timing of a given ignition event even if a change in the timing signal is received after the previous cylinder ignition event of the given ignition event.

[0080] During the combustion stroke, the combustion of the air/fuel mixture drives the piston away from the TDC position, thereby driving the rotation of the crankshaft. The combustion stroke can be defined as the time between the piston reaching TDC and the piston reaching the bottommost position (which can be referred to as bottom dead center (BDC)). During the exhaust stroke, the piston again moves to the TDC position and exhausts the byproducts of combustion through the exhaust valve 130. The byproducts of combustion are exhausted from the vehicle via an exhaust system 134.

[0081] The intake valve 122 may be controlled by the intake camshaft 140 and the exhaust valve 130 may be controlled by the exhaust camshaft 142. In various embodiments, multiple intake camshafts (including intake camshaft 140) may control multiple intake valves of cylinder 118 (including intake valve 122) and/or may control multiple cylinders (including cylinder 118). ) Group of intake valves (including intake valve 122). Similarly, multiple exhaust camshafts (including exhaust camshaft 142) may control multiple exhaust valves of cylinder 118 and/or may control exhaust valves of multiple groups of cylinders (including cylinder 118) (including exhaust valve 130). ).

[0082] The cylinder actuator module 120 may prohibit the opening of the intake valve 122 and/or the exhaust valve 130 of the deactivated cylinder. In various other embodiments, the intake valve 122 and/or the exhaust valve 130 may be controlled by a device other than a camshaft, such as an electromagnetic actuator.

[0083] The time that the intake valve 122 is opened may be changed by the intake cam phaser 148 relative to the TDC position. The time that the exhaust valve 130 is opened may be changed by the position of the exhaust cam phaser 150 relative to the TDC. The phaser actuator module 158 may control the intake cam phaser 148 and the exhaust cam phaser 150 based on the signal from the ECM 114. When implemented, the variable valve actuation (VVA) technology (not shown) may also be controlled by the phaser actuator module 158.

[0084] The engine system 100 may include a boost device that provides pressurized air to the intake manifold 110. E.g, figure 1 A turbocharger is shown that includes a turbine 160-1 that is driven by hot exhaust gas flowing through the exhaust system 134. The turbocharger also includes a cold air compressor 160-2 that is driven by a turbine 160-1 to compress the air guided to the throttle valve 112. In various implementations, a supercharger (not shown) driven by the crankshaft may compress air from the throttle valve 112 and deliver the compressed air to the intake manifold 110.

[0085] A wastegate 162 (eg, a turbine bypass valve) may allow exhaust gas to bypass the turbine 160-1, thereby reducing the boost provided by the turbocharger. For example, the boost may include the difference between the pressure in the intake manifold 110 and the pressure in the intake manifold of a naturally aspirated engine under the same operating conditions.

[0086] The ECM 114 may control the boost of the turbocharger via the boost actuator module 164. For example only, the boost actuator module 164 may adjust the boost of the turbocharger by controlling the position of the wastegate 162. In various implementations, multiple turbochargers may be controlled by the boost actuator module 164. The turbocharger may have a variable geometry that can be controlled by the boost actuator module 164.

[0087] An intercooler (not shown) can dissipate some of the heat contained in the compressed air charge, which is generated when the air is compressed. The compressed air charge may also have heat absorbed from components of the exhaust system 134. Although shown separately for illustration purposes, the turbine 160-1 and the compressor 160-2 may be attached to each other near the location of the turbine 160-1 so that the intake air is immediately adjacent to the hot exhaust.

[0088] The engine system 100 may include an exhaust gas recirculation (EGR) valve 170 that selectively redirects exhaust gas back to the intake manifold 110. The EGR valve 170 may be located upstream of the turbine 160-1. The EGR valve 170 may be controlled by the EGR actuator module 172.

[0089] The engine system 100 may use the RPM sensor 178 to measure the rotational speed of the crankshaft in units of revolutions per minute (RPM). The rotational speed of the crankshaft (ie, RPM) may also be referred to as engine speed or engine output speed.

[0090] The engine system 100 may use the vehicle speed sensor 180 to measure the speed of the vehicle. For example, the vehicle speed may be determined based on transmission output shaft speed (TOSS), one or more wheel speeds, or other suitable vehicle speed metrics. The temperature of the engine coolant may be measured using an engine coolant temperature (ECT) sensor 182. The ECT sensor 182 may be located in the engine 102 or in another location where the coolant circulates, such as a radiator (not shown).

[0091] A manifold absolute pressure (MAP) sensor 184 may be used to measure the pressure in the intake manifold 110. In various embodiments, the engine vacuum may be measured, where the engine vacuum includes the difference between the ambient air pressure and the pressure in the intake manifold 110. The mass air flow rate entering the intake manifold 110 may be measured using a mass air flow rate (MAF) sensor 186. In various implementations, the MAF sensor 186 may be located in a housing that also includes the throttle valve 112.

[0092] The throttle actuator module 116 may use one or more throttle position sensors (TPS) 190 to monitor the position of the throttle valve 112. An intake air temperature (IAT) sensor 192 may be used to measure the temperature of air drawn into the engine 102. In various embodiments, IAT can be used as the ambient air temperature. The ECM 114 may use signals from these sensors to make control decisions for the engine system 100.

[0093] The ECM 114 may communicate with a transmission control module 194 to coordinate operation of the engine 102 and a transmission (not shown). For example only, the ECM 114 may reduce engine output torque for shifting within the transmission. The torque output by the engine 102 may be transferred to the transmission through a torque transfer device (not shown, such as a torque converter).

[0094] The transmission control module 194 may also share data with the ECM 114, such as the gear ratio selected in the transmission and the commanded state of the torque converter's torque converter clutch (TCC, not shown). For example only, the state of the TCC may include a locked state or an unlocked state.

[0095] The state of TCC can be related to the amount of TCC slip. TCC slip can refer to the difference between RPM and transmission input shaft speed. When the TCC slip is approximately zero, it can be said that the TCC is in a locked state. It can also be said that the TCC is in a locked state when the TCC slip is controlled to be smaller than a predetermined slip (for example, 15 revolutions per minute). During a gear shift event, the predetermined slip may be greater. When the TCC slip is greater than the predetermined slip, it can be said that the TCC is in an unlocked state.

[0096] The ECM 114 may also communicate with a hybrid control module 196 to coordinate the operation of the engine 102 and the electric motor 198. The electric motor 198 may also act as a generator, and optionally be used to generate electrical energy for use by the vehicle electrical system and/or be stored in a battery. The electric motor 198 may also serve as a starter to drive the rotation of the crankshaft to start the engine 102. The electric motor 198 can also be used as a motor to supplement/auxiliate the engine 102.

[0097] The output of the electric motor 198 may be connected to the crankshaft of the engine 102, for example, by a belt. The electric motor 198 may be referred to as a belt-alternator-starter (BAS). Therefore, the electric motor 198 may affect the amount of torque input to the transmission. In various embodiments, the various functions of the ECM 114, the transmission control module 194, and the hybrid control module 196 may be integrated into one or more modules.

[0098] Engine actuators change one or more engine parameters by controlling related actuator values. For example only, the throttle actuator module 116 may be referred to as an engine actuator, and the throttle opening area may be the relevant actuator value. in figure 1 In the example of, the throttle actuator module 116 obtains the throttle opening area by adjusting the angle of the blade of the throttle valve 112.

[0099] Similarly, the spark actuator module 126 may be referred to as an engine actuator, and the related actuator value may refer to the amount of spark advance relative to the cylinder TDC. Other engine actuators may include a cylinder actuator module 120, a fuel actuator module 124, a phaser actuator module 158, a boost actuator module 164, and an EGR actuator module 172. For these engine actuators, the relevant actuator values ​​may respectively include the number of activated cylinders, fuel supply rate, intake and exhaust cam phaser angles, boost pressure and EGR valve opening area. The ECM 114 may control actuator values ​​to cause the engine 102 to produce a desired engine output torque and achieve desired engine parameters.

[0100] Refer now figure 2 , A functional block diagram of an exemplary engine control system 200 is shown. An exemplary embodiment of the ECM 114 includes a driver axle torque module 202. The driver axle torque module 202 can be combined as described below image 3 with Figure 4 An exemplary embodiment to determine the final driver axle request.

[0101] The axle torque arbitration module 204 arbitrates between the driver axle torque request from the driver axle torque module 202 and other axle torque requests. Other axle torque requests may include a reduction in torque requested by the traction control system when positive wheel slip is detected. When the axle torque (that is, the torque to the wheels) overcomes the friction between the wheels and the road surface, and the wheels slip in the forward direction relative to the road surface, positive wheel slip occurs. Other axle torque requests may also include torque increase requests to counteract negative wheel slip, in which the tires of the vehicle slip in the opposite direction with respect to the road surface because the axle torque is negative.

[0102] Other axle torque requests may also include brake management requests and vehicle overspeed torque requests. The brake management request may request the engine torque to be reduced to ensure that the engine output torque does not exceed the braking capacity, thereby keeping the vehicle stationary when the vehicle is stopped. The vehicle overspeed torque request may request engine torque reduction to prevent the vehicle from exceeding a predetermined speed. Other axle torque requests can also be generated through the vehicle stability control system.

[0103] The axle torque arbitration module 204 outputs the predicted torque request and the immediate torque request based on the result of the arbitration between the received axle torque requests. As described below, before being used to control the actuators of the engine 102, the predicted torque request and the immediate torque request from the axle torque arbitration module 204 can be selectively adjusted by other modules of the ECM 114.

[0104] Generally speaking, the immediate torque request is the amount of engine output torque currently expected, and the predicted torque request is the amount of engine output torque that may be required in a short time. The ECM 114 controls the engine 102 to implement the immediate torque request. However, a combination of different actuator values ​​can result in the same engine output torque. Therefore, the ECM 114 may adjust one or more actuator values ​​to allow a faster transition to the predicted torque request, while still maintaining the engine output torque at the immediate torque request.

[0105] In various implementations, the predicted torque request may be based on the driver's axle torque request. The immediate torque request may be less than the predicted torque request, such as when the driver's axle torque request is on ice (ie, low coefficient of friction) causing positive wheel slip. In this case, the traction control system (not shown) may request the engine torque reduction through the immediate torque request, and the ECM 114 reduces the engine output torque to the immediate torque request. However, the ECM 114 controls the actuator values ​​so that once the wheel slip stops, the engine 102 can quickly restart generating the predicted torque request.

[0106] The difference between the immediate torque request and the predicted torque request may be referred to as the torque reserve. The torque reserve represents the amount of additional torque (greater than the immediate torque request) that the engine 102 can start to produce with the smallest delay. Fast engine actuators are used to increase or decrease engine output torque to achieve immediate torque request. As described in more detail below, fast engine actuators can be defined in contrast to slow engine actuators.

[0107] In various embodiments, fast engine actuators can vary engine output torque within the range established by slow engine actuators. In these embodiments, the upper limit of the range is the predicted torque request, and the lower limit of the range is limited by the torque capacity of the fast engine actuators. For example only, a fast engine actuator may only be able to reduce the engine output torque by a first amount, where the first amount is a measure of the torque capacity of the fast actuator. The first amount may be changed based on engine operating conditions set by slow engine actuators. When the immediate torque request is within the range, the fast engine actuator may be set to cause the engine output torque to be equal to the immediate torque request. When the ECM 114 requests engine output torque equal to the predicted torque request, the fast engine actuator can be controlled to change the engine output torque to the upper limit of the range, which is the predicted torque request.

[0108] In comparison, fast engine actuators can change engine output torque faster than slow engine actuators. Compared to fast engine actuators, slow engine actuators respond more slowly to changes in their corresponding actuator values. For example only, slow engine actuators may include mechanical components that require time to move from one position to another in response to changes in the actuator value.

[0109] Slow engine actuators can also be characterized by the amount of time it takes for the engine output torque to respond once the slow engine actuator begins to implement the changed actuator value. Generally, the response time of slow engine actuators will be longer than the response time of fast engine actuators. In addition, even after starting to change, the engine output torque may take longer to fully respond to the change in the actuator value associated with the slow engine actuator.

[0110] For example only, if the fast engine actuator is set to an appropriate value, the ECM 114 may set the actuator value associated with the slow engine actuator to a value that enables the engine 102 to generate the predicted torque request. At the same time, given the slow actuator value, the ECM 114 may set the actuator value related to the fast engine actuator to a value that causes the engine 102 to generate an immediate torque request instead of a predicted torque request.

[0111] Therefore, the fast actuator value causes the engine 102 to generate an immediate torque request. When the ECM 114 determines to switch the engine output torque from the immediate torque request to the predicted torque request, the ECM 114 changes the actuator value associated with one or more fast actuators to a value corresponding to the predicted torque request. Because the slow actuator value has been set based on the predicted torque request, the engine 102 can generate the predicted torque request only after the delay imposed by the fast engine actuators. Therefore, the long delay caused by the use of slow engine actuators to change the engine output torque other than the above conditions is avoided.

[0112] For example only, when the predicted torque request is equal to the driver torque request, a torque reserve may be generated when the immediate torque request caused by the temporary torque reduction request is less than the drive torque request. Alternatively, the torque reserve may be generated by increasing the predicted torque request to be greater than the driver torque request while keeping the immediate torque request as the driver torque request. The resulting torque reserve can absorb the sudden increase in the required engine output torque. For example only, the sudden load from the air conditioning compressor and/or power steering pump can be balanced by increasing the immediate torque request. If the increase in the immediate torque request is less than the torque reserve, the increase is quickly produced by using fast engine actuators. Then, the predicted torque request can also be increased to re-establish the previous torque reserve.

[0113] Another exemplary use of the torque reserve is to reduce fluctuations in slow actuator values. Due to its relatively slow speed, changing slow actuator values ​​may produce control instability. In addition, slow engine actuators may include mechanical parts that can absorb more power and/or wear out more quickly when moved frequently. Generating a sufficient torque reserve allows changes in desired torque to be made by changing fast engine actuators via an immediate torque request while maintaining the actuator values ​​of slow engine actuators. For example, in order to maintain a given idle speed, the immediate torque request can vary within a certain range. If the predicted torque request is set to a level greater than this range, the change in maintaining the idle speed in the immediate torque request can be made using fast engine actuators without adjusting the slow engine actuators.

[0114] For example only, in a spark ignition engine, the spark timing may be a fast engine actuator, and the throttle opening area may be a slow engine actuator. Spark ignition engines can burn fuels including, for example, gasoline and ethanol by applying sparks. In contrast, a compression ignition engine can burn fuel including, for example, diesel fuel by compressing fuel.

[0115] After receiving the new actuator value, the spark actuator module 126 can change the spark timing of the ignition event of the next cylinder in the firing order. When the spark timing of an ignition event is set to a calibrated value, the maximum torque is produced during the combustion stroke immediately following the ignition event. However, spark timing that deviates from the calibrated value may reduce the amount of torque generated in the combustion stroke. Therefore, the spark actuator module 126 can change the engine output torque by changing the spark timing when the next ignition event occurs. For example only, a table of spark timings corresponding to different engine operating conditions may be determined during the calibration phase of the vehicle design, and a calibrated value may be selected from the table based on the current engine operating conditions.

[0116] In contrast, the change in the throttle opening area takes a long time to affect the engine output torque. The throttle valve actuator module 116 changes the throttle opening area by adjusting the angle of the blade of the throttle valve 112. Therefore, once the new actuator value is received, there is a mechanical delay when the throttle valve 112 moves from its previous position to a new position corresponding to the new actuator value.

[0117] In addition, the change in the air flow rate based on the throttle opening degree may be affected by the air delivery delay in the intake manifold 110. In addition, until the cylinder 118 receives additional air in the next intake stroke, compresses the additional air and starts the combustion stroke, an increase in air flow in the intake manifold 110 is not realized as an increase in engine output torque.

[0118] Using these actuators as an example, a torque reserve can be generated by setting the throttle opening area to a value that allows the engine 102 to generate a predicted torque request. At this time, the spark timing may be set based on an immediate torque request that is smaller than the predicted torque request. Although the throttle opening area generates sufficient air flow for the engine 102 to generate the predicted torque request, the spark timing is still delayed (reduced engine output torque) based on the immediate torque request. Therefore, the engine output torque will be equal to the immediate torque request.

[0119] When additional torque is required, such as when starting the air conditioner compressor, the spark timing can be set based on the predicted torque request. At the next ignition event, the spark actuator module 126 may return the spark advance to the calibrated value, allowing the engine 102 to produce engine output torque equal to the predicted torque request because the air flow already exists. Therefore, the engine output torque can be rapidly increased to the predicted torque request without experiencing the delay caused by changing the throttle opening area.

[0120] The axle torque arbitration module 204 may output the predicted torque request and the immediate torque request to the propulsion torque arbitration module 206. In various implementations, the axle torque arbitration module 204 may output the predicted torque request and the immediate torque request to the hybrid optimization module 208. The hybrid optimization module 208 determines how much torque should be produced by the engine 102 and how much torque should be produced by the electric motor 198. The hybrid optimization module 208 then outputs the revised predicted torque request and the immediate torque request to the propulsion torque arbitration module 206. In various implementations, the hybrid optimization module 208 may be implemented in the hybrid control module 196.

[0121] The predicted torque request and the immediate torque request received by the propulsion torque arbitration module 206 are converted from the axle torque domain (torque at the wheels or axle) to the propulsion torque domain (torque at the crankshaft). This conversion may occur before or after the hybrid optimization module 208, or as part of the hybrid optimization module 208, or instead of the hybrid optimization module 208.

[0122] The propulsion torque arbitration module 206 arbitrates between the converted predicted torque request and the immediate torque request and other propulsion torque requests. The propulsion torque arbitration module 206 generates an arbitrated predicted torque request and an arbitrated immediate torque request. The arbitrated torque can be generated by selecting the winning request from the received requests. Alternatively or additionally, the arbitrated torque may be generated by modifying one of the received requests based on another one or more of the received requests.

[0123] Other propulsion torque requests may include a decrease in engine torque requested for engine overspeed protection, an increase in engine torque requested to prevent stalling, and a decrease in engine torque requested by the transmission control module 194 to make a gear shift. The clutch fuel interruption can also generate other propulsion torque requests. When the driver depresses the clutch pedal in a manual transmission vehicle to prevent sudden changes in engine speed (rapid rise), the clutch fuel interruption reduces the engine output torque.

[0124] Other propulsion torque requests can also include engine shutdown requests, which can be activated when a critical fault is detected. For example only, critical faults may include detection of vehicle theft, a stuck starter motor, electronic throttle control issues, and unexpected torque increases. In various embodiments, when an engine shutdown request occurs, the arbitration selects the engine shutdown request as the winning request. When an engine shutdown request occurs, the propulsion torque arbitration module 206 may output zero as the arbitrated torque.

[0125] In various embodiments, the engine shutdown request may shut down the engine 102 independently of the arbitration process. The propulsion torque arbitration module 206 may still receive the engine shutdown request so that, for example, appropriate data may be fed back to other torque requesters. For example, all other torque requesters can be notified that they have failed in the ruling.

[0126] The RPM control module 210 may also output the predicted torque request and the immediate torque request to the propulsion torque arbitration module 206. When the ECM 114 is in the RPM mode, the torque request from the RPM control module 210 will win the arbitration. When the driver removes the pressure on the accelerator pedal, such as when the vehicle is idling or coasting, the RPM mode can be selected. Alternatively or additionally, when the predicted torque request from the axle torque arbitration module 204 is less than the calibrated torque value, such as when the engine 102 is idling, the RPM mode may be selected.

[0127] The RPM control module 210 receives the desired RPM from the RPM trajectory module 212, and controls the predicted torque request and the immediate torque request to reduce the difference between the desired RPM and the actual RPM. For example only, the RPM trajectory module 212 may output the desired RPM for the linear reduction of the vehicle coasting until the idle RPM is reached. The RPM trajectory module 212 may then continue to output the idle RPM as the desired RPM.

[0128] The reserve/load module 220 receives the arbitrated predicted torque request and the immediate torque request from the propulsion torque arbitration module 206. The reserve/load module 220 may adjust the arbitrated predicted torque request and the arbitrated immediate torque request to generate a torque reserve and/or compensate for one or more loads. Then, the reserve/load module 220 outputs the adjusted predicted torque request and the adjusted immediate torque request to the actuation module 224.

[0129] For example only, a delayed spark advance may be required for a catalyst light-off process or a cold start emission reduction process. Therefore, the reserve/load module 220 may increase the adjusted predicted torque request above the adjusted immediate torque request to generate a delayed spark for the cold start emission reduction process. In another example, for example, the air/fuel ratio and/or mass air flow rate of the engine 102 may be directly changed through diagnostic intrusive equivalence ratio detection and/or new engine purification. Before starting these processes, a torque reserve can be generated or increased to quickly compensate for the reduction in engine output torque caused by the lean air/fuel mixture during these processes.

[0130] The reserve/load module 220 may also generate or increase a torque reserve in anticipation of future loads, such as power steering pump operation or engagement of an air conditioning (A/C) compressor clutch. When the driver first requests air conditioning, a reserve for the engagement of the A/C compressor clutch can be generated. The reserve/load module 220 may increase the adjusted predicted torque request while keeping the adjusted immediate torque request unchanged to generate a torque reserve. Then, when the A/C compressor clutch is engaged, the reserve/load module 220 may increase the immediate torque request by the estimated load of the A/C compressor clutch.

[0131] The actuation module 224 receives adjusted predicted and immediate torque requests from the reserve/load module 220. The actuation module 224 determines how the adjusted predicted torque request and the immediate torque request will be achieved. The actuation module 224 may be specific to the engine type. For example only, a spark ignition engine may implement the actuation module 224 differently than a compression ignition engine, or the actuation module 224 may use a different control scheme.

[0132] In various embodiments, the actuation module 224 may define a boundary between a module common to all engine types and a module specifically determined according to the engine type. For example only, engine types may include spark ignition and compression ignition. The modules before the actuation module 224, for example, the propulsion torque arbitration module 206, may be common to various engine types, and the actuation module 224 and subsequent modules may be specific to the engine type.

[0133] For example only, in a spark ignition engine, the actuation module 224 may change the opening of the throttle valve 112 as a slow actuator that allows a wide range of torque control. The actuation module 224 may use the cylinder actuator module 120 to deactivate the cylinder, which also provides a wide range of torque control, but may also be slow and may involve drivability and emissions issues. The actuation module 224 may use spark timing as a fast actuator. However, spark timing may not provide a wide range of torque control. In addition, the amount of torque control that can be achieved with changes in spark timing (known as spark reserve capability) can vary with changes in air flow.

[0134] In various implementations, the actuation module 224 may generate an air torque request based on the adjusted predicted torque request. The air torque request may be equal to the adjusted predicted torque request, thereby setting the air flow so that the adjusted predicted torque request can be achieved through changes to other engine actuators.

[0135] The air control module 228 may determine the desired actuator value based on the air torque request. For example, the air control module 228 may control a desired manifold absolute pressure (MAP), a desired throttle area, and/or a desired air volume per cylinder (APC). The desired MAP can be used to determine the desired boost, and the desired APC can be used to determine the desired cam phaser position. In various implementations, the air control module 228 may also determine the amount of opening of the EGR valve 170.

[0136] The actuation module 224 may also generate spark torque requests, cylinder shut-off torque requests, and fuel mass torque requests. The spark control module 232 may use the spark torque request to determine how much to retard the spark timing from the calibrated spark advance (reduce the engine output torque).

[0137] The cylinder shut-off torque request may be used by the cylinder control module 236 to determine how many cylinders to deactivate. The cylinder control module 236 may instruct the cylinder actuator module 120 to deactivate one or more cylinders of the engine 102. In various embodiments, a predetermined group including one or more cylinders may be jointly deactivated.

[0138] The cylinder control module 236 may also instruct the fuel control module 240 to stop fueling deactivated cylinders, and may instruct the spark control module 232 to stop providing spark to deactivated cylinders. In various implementations, once any fuel/air mixture already present in a cylinder has been burned, the spark control module 232 simply stops providing spark for that cylinder.

[0139] In various embodiments, the cylinder actuator module 120 may include a hydraulic system that selectively disengages intake and/or exhaust valves from corresponding camshafts for one or more cylinders to stop Use these cylinders. For example only, the valves for half of the cylinders are hydraulically coupled or disconnected in groups by the cylinder actuator module 120. In various implementations, cylinders can be deactivated simply by stopping fuel supply to these cylinders without stopping the opening and closing of the intake and exhaust valves. In these embodiments, the cylinder actuator module 120 may be omitted.

[0140] The fuel control module 240 may change the amount of fuel provided to each cylinder based on the fuel quality torque request from the actuation module 224. During normal operation of a spark ignition engine, the fuel control module 240 may attempt to maintain a stoichiometric air/fuel ratio. Therefore, the fuel control module 240 may determine the fuel mass that produces stoichiometric combustion when combined with the current air mass of each cylinder. The fuel control module 240 may instruct the fuel actuator module 124 to inject the fuel mass to each activated cylinder.

[0141] Based on the fuel quality torque request, the fuel control module 240 may adjust the air/fuel ratio relative to the stoichiometric ratio to increase or decrease the engine output torque. The fuel control module 240 may then determine the fuel quality for each cylinder to achieve the desired air/fuel ratio. In diesel systems, fuel quality can be the main actuator that controls the output torque of the engine.

[0142] The torque estimation module 244 may estimate the torque output of the engine 102. This estimated torque can be used by the air control module 228 to perform closed-loop control of engine airflow parameters such as throttle area, MAP, and phaser position. As an example only, the following torque relations can be defined,

[0143] (1) T=f(APC,S,I,E,AF,OT,#)

[0144] The torque (T) is the air volume per cylinder (APC), spark advance (S), intake cam phaser position (I), exhaust cam phaser position (E), air/fuel ratio (AF), oil Function of temperature (OT) and number of activated cylinders (#). Additional variables may also be considered, such as the degree of exhaust gas recirculation (EGR) valve opening. The relationship can be modeled by equations and/or can be stored as a lookup table.

[0145] The torque estimation module 244 may determine APC based on MAF and RPM, thereby allowing closed-loop air control based on actual air flow. The intake and exhaust cam phaser positions used can be based on the actual position because the phaser can be moved toward the desired position.

[0146] The actual spark advance can be used to estimate the engine output torque. When the calibrated spark advance value is used to estimate engine output torque, the estimated torque may be referred to as estimated air torque, or only air torque. The air torque may be an estimate of how much torque the engine 102 can produce with the current air flow when spark retard is cancelled (ie, the spark timing is set to the calibrated spark advance value) and all cylinders are refueled.

[0147] The air control module 228 may output the desired area signal to the throttle actuator module 116. Then, the throttle actuator module 116 adjusts the throttle valve 112 to produce the desired throttle area. The air control module 228 may generate a desired area signal based on the inverse torque model and the air torque request. The air control module 228 may use the estimated air torque and/or MAF signal in order to perform closed loop control. For example, the desired area signal can be controlled to minimize the difference between the estimated air torque and the air torque request.

[0148] The air control module 228 may output a desired manifold absolute pressure (MAP) signal to the boost scheduling module 248. The boost scheduling module 248 uses the desired MAP signal to control the boost actuator module 164. Then, the boost actuator module 164 controls one or more turbochargers (eg, turbochargers including the turbine 160-1 and the compressor 160-2) and/or superchargers.

[0149] The air control module 228 may also output a desired air per cylinder (APC) signal to the phaser scheduling module 252. Based on the desired APC signal and RPM signal, the phaser scheduling module 252 may utilize the phaser actuator module 158 to control the position of the intake and/or exhaust cam phasers 148 and 150.

[0150] Referring back to the spark control module 232, the calibrated spark advance value may be changed based on various engine operating conditions. For example only, the torque relationship can be inverted to solve for the desired spark advance. For a given torque request (T des ), the desired spark advance (S des ) Can be determined based on the following relationship:

[0151] (2).

[0152] This relationship can be implemented as an equation and/or lookup table. The air/fuel ratio (AF) may be the actual air/fuel ratio, as reported by the fuel control module 240.

[0153] When the spark advance is set to the calibrated spark advance, the resulting torque will be as close as possible to the average best torque (MBT). When using fuel with an octane number greater than a predetermined threshold and using a stoichiometric fuel addition, MBT refers to the maximum engine output torque generated for a given air flow as the spark advance increases. The spark advance when this maximum torque occurs is called MBT spark. Due to, for example, fuel quality (such as when using lower octane fuel) and environmental factors, the calibrated spark advance may be slightly different from the MBT spark. The torque at the calibrated spark advance can therefore be less than MBT.

[0154] Refer now image 3 , A functional block diagram of an exemplary embodiment of the driver axle torque module 202 is presented. The driver axle torque module 202 may include a pedal request module 302, a parameter determination module 306, a conversion module 310, and a driver request module 314. The driver axle torque module 202 may also include a brake assist request module 318, an arbitration module 322, a shaping module 324, a final driver request module 326, and a conversion module 330.

[0155] The pedal request module 302 determines a pedal torque request (PTR). The pedal request may belong to the propulsion torque domain (ie, the torque at the crankshaft). The pedal request module 302 may determine the pedal torque request based on the APP, vehicle speed, zero pedal torque, and/or other suitable parameters. For example only, the pedal request module 302 may use the following equation to determine the pedal torque request:

[0156] (3) ,

[0157] Among them, PTR is the pedal torque request (for example, Nm), ZPT is the zero pedal torque (for example, Nm) when the accelerator pedal is in the zero position (that is, 0%), and 100% PedalTorque is when the accelerator pedal is fully depressed (that is, Nm). , 100%) at the maximum torque (for example, Nm) at the crankshaft, AmbCorr is the correction (for example, coefficient) of ambient air pressure, and PedalCorr is the correction (for example, coefficient) of APP amplitude.

[0158] Zero pedal torque (ZPT) can be combined with RPM control module 210 Figure 4 An exemplary embodiment of is determined as described below. 100% PedalTorque, ambient pressure correction, and/or pedal correction may be provided by the parameter determination module 306 or another suitable source. For example only, 100% PedalTorque can be determined using the following formula:

[0159] (4) ,

[0160] Among them, MaxEngTorque is the maximum engine torque output (for example, Nm), MaxMotorTorque is the maximum torque output of the electric motor 198 (for example, Nm), and MotorCorr is the correction of how much torque output of the electric motor 198 is converted into the torque at the crankshaft (for example ,coefficient). The maximum engine torque output and the maximum torque output of the electric motor 198 may be determined based on engine speed and other suitable parameters. The ambient pressure correction may be determined based on a comparison of ambient air pressure and a predetermined ambient air pressure. The pedal correction may be determined based on where the APP is within the activation range of the accelerator pedal (for example, between 0% and 100%).

[0161] The conversion module 310 receives the pedal torque request and converts the pedal torque request into an axle torque domain (ie, torque at the wheel or axle). After being converted to the axle torque domain, the request may refer to the converted pedal request (CPR). The conversion module 310 may convert the pedal torque request based on, for example, driveline losses, a gear ratio selected within the transmission, one or more torque ratios, and other suitable parameters.

[0162] The driver request module 314 determines the driver axle request (DAR) based on the converted pedal request. The driver's axle request belongs to the axle torque domain (ie, the torque at the wheel or axle). The driver request module 314 further determines the driver's axle request based on the brake assist torque request. For example only, the driver request module 314 may determine the driver's axle torque request using the following equation:

[0163] (5) ,

[0164] Among them, DAR is the driver's axle request (for example, Nm), CPR is the converted pedal request (for example, Nm), and BAR is the brake assist torque request (for example, Nm).

[0165] The brake assist request module 318 may determine a brake assist torque request (eg, Nm) and provide the brake assist torque request to the driver request module 314. A brake assist request may refer to a decrease in engine output torque that facilitates the generation of regenerative braking by the electric motor 198, which is requested to assist the mechanical braking of the vehicle during vehicle braking. Performing regenerative braking generates electrical power and allows a reduced amount of mechanical braking to be used. The brake assist request module 318 may determine the brake assist request based on the BPP. The hybrid control module 196 or the hybrid optimization module 208 may control the regenerative braking performed by the electric motor 198 based on the brake assist request.

[0166] The arbitration module 322 receives driver axle requests and other driver torque requests, and arbitrates between the received requests. For example only, the arbitration module 322 may arbitrate between the driver's axle request and the cruise torque request. The arbitration module 322 outputs the arbitration winner as the original driver axle request (RDAR) (for example, Nm). The original driver's axle request belongs to the axle torque domain (ie, the torque at the wheel or axle).

[0167] The shaping module 324 receives the original driver's axle request and selectively shapes the original driver's axle request into a reshaped driver's axle request (SDAR). The shaping module 324 may shape the original driver's axle request to, for example, reduce or prevent the "shock" that the driver may experience when stepping on or releasing the accelerator pedal. For example only, the shaping module 324 may apply one or more filters to the original driver's axle request to determine the shaped driver's axle request. The reshaped driver's axle request belongs to the axle torque domain (that is, the torque at the wheel or axle).

[0168] The final driver request module 326 determines a final driver axle request (FDAR), and the final driver axle request is provided to the axle torque arbitration module 204 for arbitration with other axle torque requests. The final driver request module 326 may generally set the final driver's axle request (for example, Nm) to be equal to the reshaped driver's axle request.

[0169] The final driver request module 326 can selectively limit the final driver's axle request to the smallest drivable axle torque. In other words, the final driver request module 326 can set the final driver’s axle request equal to the larger of the reshaped driver’s axle request and the smallest drivability axle torque (for example, Nm). One. The smallest drivable axle torque may refer to the smallest amount of vehicle selected to maintain the drivability of the vehicle (for example, to prevent engine stall) and to minimize fuel consumption (for example, by using decelerating fuel cut and/or regenerative braking). Bridge torque.

[0170] The conversion module 330 may determine the minimum drivability axle torque based on the total minimum drivability torque. More specifically, the conversion module 330 may convert the total minimum drivability torque from the propulsion torque domain to the axle torque domain. This conversion may be similar or equivalent to the conversion performed by the conversion module 310.

[0171] The total minimum drivable torque may refer to the amount of torque (for example, Nm) selected at the crankshaft to maintain vehicle drivability and minimize fuel consumption. Combine below Figure 4 To further discuss the total minimum drivability torque.

[0172] Refer now Figure 4 , A functional block diagram of an exemplary implementation of the RPM control module 210 is given. The RPM control module 210 may include an RPM immediate torque module 404, an RPM predicted torque module 408, an idle speed correction module 412, a driver zero pedal torque (ZPT) module 420, a ZPT module 424, and a ZPT correction module 428. The RPM control module 210 may also include a total minimum torque module 430, an engine capacity module 434, a minimum drivability propulsion torque module 438, a TCC state determination module 442, a minimum TCC unlocked torque module 446, and a minimum TCC locked torque module 450.

[0173] The RPM immediate torque module 404 determines the RPM immediate torque request. The RPM predicted torque module 408 determines the RPM predicted torque request. The RPM immediate and predicted torque requests may be provided to the propulsion torque arbitration module 206 for arbitration with other propulsion torque requests. The RPM instant and predicted torque modules 404 and 408 may control the RPM instant and predicted torque requests, respectively, to reduce the difference between the desired RPM and RPM.

[0174] The idle speed correction module 412 determines the idle speed correction. Idle speed correction can be used to determine the driver's axle request as described above. The idle speed correction may refer to a learned torque correction (for example, Nm) in the axle torque domain to compensate for calculation differences, component differences, and other differences between the vehicle and a predetermined vehicle. For example only, these differences may include the difference between the estimated engine torque output and the actual engine torque output, the difference between the desired torque load of the transmission and the actual torque load of the transmission, and other suitable differences.

[0175] The driver ZPT module 420 determines the driver ZPT (eg, Nm). The driver ZPT module 420 may determine the driver ZPT based on the RPM and PRNDL location. The driver ZPT may correspond to the desired engine output torque when the accelerator pedal is not depressed (ie, when the accelerator pedal is 0%). The desired engine torque output may cause the vehicle to coast when the driver releases the accelerator pedal, or may cause the vehicle to move at minimum vehicle speed (ie, slow speed) when the brake is not depressed and the vehicle is on a flat surface.

[0176] The ZPT module 424 determines ZPT (for example, Nm) based on the driver's ZPT and the total minimum drivable torque. The ZPT module 424 may generally set the ZPT equal to the driver's ZPT and limit the ZPT to the total minimum drivable torque. In other words, the ZPT module 424 may set the ZPT equal to the larger of the driver's ZPT and the total minimum drivability torque. Limiting the ZPT to the total minimum drivability torque can prevent deadlock when the driver steps on the accelerator pedal. Deadlock pedal may refer to no torque change when the driver steps on the accelerator pedal.

[0177] The ZPT correction module 428 may determine torque corrections in conjunction with idle speed corrections to account for calculated differences, component differences, and other differences between the vehicle and the predetermined vehicle as described above. For example only, the torque correction may be a propulsion torque domain equivalent to the idle speed correction. More specifically, the torque correction may be idle speed correction after conversion to the propulsion torque domain. The ZPT correction module 428 determines the corrected ZPT based on the ZPT and the torque correction. For example only, the ZPT correction module 428 may determine the corrected ZPT based on the sum of the ZPT and the torque correction.

[0178] The total minimum torque module 430 determines the total minimum drivable torque (for example, Nm). For example only, the total minimum torque module 430 may set the total minimum drivability torque to the larger one of the engine capacity and the minimum drivability propulsion torque. The engine capacity may be determined by the engine capacity module 434. The minimum drivability propulsion torque can be determined by the minimum drivability propulsion torque module 438, which will be described in more detail below.

[0179] The engine capacity module 434 may determine the engine capacity based on the minimum torque of the engine 102 and the maximum braking torque of the electric motor 198. For example only, the engine capacity module 434 may determine the engine capacity (eg, Nm) based on a minimum engine torque (eg, Nm) that is less than the maximum braking torque (eg, Nm). Engine capacity is the domain of propulsion torque.

[0180] The maximum braking torque may refer to the maximum braking torque that the electric motor 198 can apply during regenerative braking. For example only, the maximum braking torque may be approximately 150 Nm of braking torque at the crankshaft. When the deceleration fuel cutoff (DFCO) is not allowed, the minimum engine torque can refer to the engine torque output with the minimum air volume per cylinder (APC). Under the minimum air volume per cylinder (APC), proper combustion will occur and produce Maximum delay of spark timing. When running DFCO, the minimum engine torque may refer to the amount of torque necessary to rotate the crankshaft during DFCO. For example only, the minimum engine torque may be about 30 Nm. For example, when the exhaust gas may include more than a predetermined amount of predetermined exhaust gas components or in order to prevent engine damage, DFCO may not be allowed.

[0181] The minimum drivability propulsion torque module 438 may determine the minimum drivability propulsion torque (for example, Nm). The minimum drivability propulsion torque module 438 may determine the minimum drivability propulsion torque based on the minimum unlocked TCC torque and the minimum locked TCC torque. The smallest drivability propulsion torque module 438 can selectively set the smallest drivability propulsion torque equal to the smallest unlocked TCC torque or the smallest locked TCC torque and can selectively set the smallest unlocked TCC torque Convert one of the TCC torque and the minimum locked TCC torque to the other.

[0182] The minimum drivability propulsion torque module 438 may selectively convert the minimum drivability propulsion torque into a minimum unlocked TCC torque or a minimum locked TCC torque based on one or more parameters. For example only, the parameters may include the state of the TCC, the reshaped driver's axle request, the driver's axle request, the minimum unlocked TCC torque, and the corrected ZPT. The minimum drivability propulsion torque module 438 may also determine how to implement the conversion based on one or more parameters.

[0183] The TCC state determination module 442 may generate a TCC state signal, which indicates whether the TCC is in a locked state or an unlocked state. For example only, the TCC state determination module can set the TCC state signal to the working state (for example, 5V) when the TCC is in the locked state and set the TCC state signal to the non-working state when the TCC is in the unlocked state ( For example, 0V).

[0184] The TCC state determination module 442 may determine whether the TCC is in the locked state or the unlocked state based on one or more parameters such as the TCC slip, the PRNDL position, and the command state of the TCC. For example only, when the commanded state is in the locked state, the TCC slip is less than the predetermined slip, and the PRNDL is not in the neutral position or the parking position for at least the predetermined period of time, the TCC state determining module 442 may determine that the TCC is locked status. The TCC state determination module 442 may also verify that no communication failure or hardware failure is detected before the TCC state signal is set to indicate that the TCC is in the locked state. The predetermined slip may be greater than or equal to the slip when the TCC is in a controlled slip state.

[0185] The minimum TCC unlocked torque module 446 may determine the minimum unlocked TCC torque (eg, Nm). For example only, the minimum TCC unlocked torque module 446 may determine the minimum unlocked TCC torque based on the RPM and the selected gear ratio in the transmission. When the TCC is in the unlocked state, the minimum unlocked TCC torque may refer to the minimum amount of propulsion torque at the TCC to prevent the engine from stalling.

[0186] The minimum TCC locking torque module 450 may determine the minimum locking TCC torque (eg, Nm). For example only, the minimum TCC lock torque module 450 may determine the minimum lock TCC torque based on RPM, gear ratio, and transmission oil temperature. When the TCC is in the locked state, the minimum locked TCC torque may refer to the minimum amount of torque at the TCC to prevent the engine from stalling. A torque that is less than the minimum locked TCC torque may cause the TCC to slip and thus prevent torque from being transferred from the transmission to the engine 102.

[0187] The minimum TCC unlock torque is greater than or equal to the minimum TCC lock torque. To ensure that this relationship remains true, the minimum TCC unlocked torque module 446 may set the minimum unlocked TCC torque to be equal to the greater of the minimum unlocked TCC torque and the minimum locked TCC torque.

[0188] When the driver's ZPT is greater than the minimum unlocked TCC torque, the minimum drivability propulsion torque module 438 can convert the minimum driveability propulsion torque into the minimum unlock TCC torque or the minimum locked TCC torque. For example only, when the TCC is in the unlocked state and the driver’s ZPT is greater than the minimum unlocked TCC torque, the smallest drivable propulsion torque module 438 can convert the smallest drivable propulsion torque to the smallest unlocked TCC Torque. When the TCC is in the locked state and the driver's ZPT is greater than the minimum unlocked TCC torque, the minimum drivability propulsion torque module 438 can convert the minimum drivability propulsion torque into the minimum locked TCC torque.

[0189] For these two transitions, the smallest drivable propulsion torque module 438 can take a skip step. The skip step conversion may include converting the minimum drivable propulsion torque to the minimum unlocked or locked TCC torque in one control loop (ie, one step). Converting the smallest drivable propulsion torque within a control loop can prevent the engine by ensuring that the smallest drivable propulsion torque reaches the minimum unlocked or locked TCC torque before the driver's ZPT drops to the minimum unlocked TCC torque. Stall.

[0190] When the reshaped driver's axle request is less than the minimum unlocked TCC torque or when the original driver's axle request is less than the corrected ZPT, the minimum drivability propulsion torque module 438 can switch based on whether the TCC is in the locked state or the unlocked state The smallest driving torque. For example only, when the TCC is in the unlocked state and the locked state, the smallest drivable propulsion torque module 438 can convert the smallest drivable propulsion torque into the smallest unlocked TCC torque and the smallest locked TCC torque, respectively . For this type of transition, the smallest drivable propulsion torque module 438 can be used in what can be called a rapid ramp change.

[0191] The rapid ramp change may include using steps with a predetermined amplitude or using steps to complete the conversion within a predetermined period of time to perform the conversion. The minimum drivability propulsion torque module 438 may select or determine the magnitude of the step or the predetermined time based on one of the minimum unlocked TCC torque and the minimum locked TCC torque to which the minimum drivable propulsion torque is to be converted segment. Merely by way of example, compared to the transition to the minimum unlocked TCC torque, the steps may be larger in the step of switching to the minimum unlocked TCC torque, and the predetermined time period may be shorter. This is because the transition to the minimum unlocked TCC torque can be performed to prevent the engine from stalling while the transition to the locked TCC torque can be used to save fuel (by using DFCO earlier).

[0192] When the reshaped driver's axle request is greater than the minimum unlocked TCC torque and when the driver's axle request is greater than the corrected ZPT, the smallest drivability propulsion torque module 438 can convert the smallest drivability propulsion torque to the minimum Lock the TCC torque. The minimum drivability propulsion torque module 438 can be converted in a manner called a slow ramp change, where the slow speed is defined relative to the fast ramp change described above. In other words, using a slow ramp change to switch to the minimum locked TCC torque may take longer to complete than using a fast ramp change to switch. This type of transition can be performed slowly because the reshaping driver's axle request is greater than the minimum unlocked TCC torque. When the TCC is in the unlocked state, the engine stall may occur when the minimum unlocked TCC torque is less than that. Slow ramp changes can provide a smooth (eg linear) feel during the transition. If the driver steps on the accelerator pedal, the ZPT can be changed by the total minimum drivability torque and the relationship between APP and the pedal torque request can be changed in a relatively short period of time to avoid engine stall.

[0193] The minimum drivability propulsion torque module 438 may determine the ramp rate of the slow ramp change based on, for example, a time period when the reshaped driver's axle request is less than or equal to the minimum unlocked TCC torque. For example only, the ramp rate may decrease as time increases. Switching to minimum locked TCC torque can be performed to save fuel. More specifically, DFCO and/or regenerative braking can be performed earlier, thus saving fuel.

[0194] As described above, the total minimum torque module 430 can set the total minimum drivability torque to the larger one of the engine capacity and the minimum drivability propulsion torque. The ZPT module 424 sets ZPT to be the larger of the driver's ZPT and the total minimum drivability torque. Since the pedal request module 302 determines the pedal request based on ZPT, the total minimum drivable torque can be reflected in the pedal request. Therefore, the total minimum drivability torque can also be reflected in the reshaped driver's axle request, the converted reshaped driver's axle request, the driver's axle request, and the final driver's axle request. The final driver request module 326 can also set the final driver’s axle request as the driver’s axle request and the minimum drivability axle request (ie, converted into the total minimum drivability torque in the axle torque domain). ) The larger one.

[0195] Reference now Figure 5A-5C , A flowchart showing an exemplary method 500 is described. Control may begin at 504, where control may determine the driver's ZPT. Control may determine the driver's ZPT based on, for example, RPM and PRNDL location.

[0196] At 508, control may determine a minimum unlocked TCC torque and a minimum locked TCC torque. Control may determine the minimum unlocked TCC torque based on PRM and gear ratio, and control may determine the minimum locked TCC torque based on RPM, gear ratio, and transmission oil temperature. At 512, control may determine engine capacity. The control may determine the engine capacity based on the difference between the minimum engine torque and the maximum braking torque.

[0197] At 516, control may determine whether the TCC lock condition is satisfied. If so, control may increase the timer at 520 and continue at 524; if not, control may reset the timer at 528 and continue at 524. When the command state of the TCC is the locked state or the controlled slip state, the slip is less than the predetermined slip, and the PRNDL position is not the neutral position or the parking position, the TCC lock condition is satisfied.

[0198] At 524, control may determine whether the timer is greater than a predetermined period of time. If it is, then control can determine at 532 that the TCC is locked and Figure 5B B continues; if not, then control can determine at 536 that TCC is in an unlocked state and Figure 5B The B continues.

[0199] Reference now Figure 5B , Control can be entered from B, and at 540 it is determined whether the driver’s ZPT is greater than the minimum unlocked TCC. If not, control can continue to 548; if yes, control can continue at 544. At 544, control can be as Figure 5A Deterministic way to determine whether the TCC is locked. If so, control can continue to 545; if not, control can continue at 546.

[0200] At 545, control may change the minimum drivability propulsion torque to the minimum lock TCC torque in one step. In other words, at 545, the minimum drivability propulsion torque may be set as the minimum lock TCC torque. At 546, control can change the minimum drivability propulsion torque to the minimum unlocked TCC torque in one step. In other words, at 546, the minimum drivable propulsion torque may be set to the minimum unlocked TCC torque. After 545 or 546, control can continue at 568, which will be discussed below.

[0201] At 548, control may determine whether the reshaped driver's axle request is less than the minimum unlocked TCC torque or whether the original driver's axle request is less than the corrected ZPT. If one item is yes, then control can continue to 552; if both items are no, then control can continue at 562, which will be discussed further below.

[0202] At 552, the control can be as Figure 5A Deterministic way to determine whether the TCC is locked. If yes, control can continue to 556; if not, control can continue at 560. At 556, the control can use rapid ramp changes and convert the minimum drivable propulsion torque to the minimum locked TCC torque. At 560, the control can use rapid ramp changes and convert the minimum drivable propulsion torque to the minimum unlocked TCC torque. The rapid ramp change to the minimum unlocked TCC torque may be faster than the rapid ramp change to the minimum locked TCC torque (ie, at a greater ramp rate).

[0203] At 562 (at 548, when the reshaped driver's axle request is greater than or equal to the minimum unlocked TCC torque and the original driver's axle request is greater than or equal to the corrected ZPT), the control may determine the ramp change for the slow ramp change transition rate. Control may determine the ramp rate based on, for example, a period of time that the reshaped driver's axle request is less than or equal to the minimum unlocked TCC torque. At 564, the control may use the predetermined ramp rate and use the ramp rate to convert the minimum drivable propulsion torque to the minimum lock TCC torque. After 564, 560, or 556, control may continue at 568.

[0204] At 568, control may set the total minimum drivability torque based on the engine capacity or the minimum drivability propulsion torque. For example only, the control may set the total minimum drivability torque equal to the larger one of the minimum drivability torque and the engine capacity. Control can advance to Figure 5C C.

[0205] Reference now Figure 5C , Control can be entered from C, and at 570 the minimum drivability axle torque is determined. The control may determine the minimum drivability axle torque, for example, by converting the minimum drivability propulsion torque into the axle torque domain. At 574, control may determine ZPT. For example only, the control may set the ZPT equal to the larger of the total minimum drivability torque and the driver's ZPT. At 578, control may determine the pedal torque request based on ZPT.

[0206] At 582, control may determine the driver's axle request. For example only, control may determine the driver's axle request by converting the pedal torque request to the axle torque domain and subtracting the brake assist torque request after the conversion. At 586, control may determine the original driver's axle request. Control may determine the original driver's axle request, for example, based on the result of arbitrating the driver's axle request with other driver torque requests (eg, cruise torque requests). At 590, control may optionally request reshaping of the original driver's axle. The result of selective shaping can be referred to as shaping the driver's axle request.

[0207] At 592, control may determine the final driver's axle request. For example only, the control may set the final driver's axle request to be equal to the larger one of the reshaped driver's axle request and the minimum drivability axle torque. The control can then end.

[0208] Now, those skilled in the art can recognize from the above description that the broad teachings of the present invention can be implemented in various forms. Therefore, although the present disclosure includes specific examples, the true scope of the present disclosure should not be limited by this, because after studying the drawings, the specification and the claims, those skilled in the art will know other modifications.