Method for controlling a hybrid powertrain system in response to an engine temperature

Abstract

Method for controlling a hybrid powertrain system (20) comprising an internal combustion engine (40), wherein the method comprises controlling the operation of the hybrid powertrain system (20) in response to a trajectory of a preferred minimum coolant temperature for the internal combustion engine (40), wherein controlling the operation of the hybrid powertrain system (20) comprises performing a control of the hybrid powertrain system (20) in response to the trajectory of the preferred minimum coolant temperature for the internal combustion engine (40) and in response to an engine coolant temperature, characterized in that several trajectories (312, 314, 316, 318, 320) of the preferred minimum coolant temperature comprise minimum coolant temperatures related to a vehicle running time (310) that are associated with an initial warm-up phase of operation and a stabilized phase of operation, An outside air temperature, the vehicle running time (310) and a vehicle warm-up time are used to select the trajectory of the preferred minimum coolant temperature from the several trajectories (312, 314, 316, 318, 320), and The execution of the control of the hybrid powertrain system (20) includes: a basic characteristic map of an engine heat dissipation response for the internal combustion engine (40) is adapted with a scalar multiplier, which is determined with reference to a difference between the trajectory of the preferred minimum coolant temperature for the internal combustion engine (40) and the engine coolant temperature, wherein the basic characteristic map of the engine heat dissipation response includes basic operating costs (430) for heat dissipation, which are determined with reference to engine operating points defined by an engine speed (420) and an engine torque (410) for the internal combustion engine (40), and wherein the scalar multiplier is adjusted to minimize the operation of the internal combustion engine (40) associated with achieving the preferred minimum coolant temperature; and The operation of the internal combustion engine (40) is controlled to generate heat in order to ensure that the coolant temperature follows the trajectory of the preferred minimum coolant temperature.

Description

TECHNICAL AREA

[0001] This disclosure concerns the control of hybrid powertrain systems that include torque motors and internal combustion engines. BACKGROUND

[0002] Vehicle systems include powertrain systems that provide output torque for a drive. These powertrain systems encompass hybrid systems, all-electric systems, and extended-range electric systems, which can be configured to operate in various modes to generate torque and transmit it to a final drive. Such powertrain systems utilize torque-generating devices, clutches, and transmissions. The torque-generating devices can include internal combustion engines and electrically driven motors / generators, i.e., electric machines.

[0003] Known powertrain systems use control schemes to minimize fuel consumption in an internal combustion engine while responding to an operator's torque demands regarding traction power. Known control schemes that minimize fuel consumption include deceleration fuel cut-off (DFCO) schemes and engine auto-stop schemes. The consumed fuel generates power and heat that can be used elsewhere in the powertrain system and in the vehicle, such as in the vehicle's passenger compartment. Known vehicle systems include operator-controlled HVAC systems that generate thermal and electrical demands, which may be stochastic in nature and may deviate from the nominally expected warm-up behavior.

[0004] Under certain powertrain operating conditions, a powertrain system operated solely to minimize fuel consumption may not operate an internal combustion engine in a manner that generates heat to meet thermal requirements and needs, such as passenger compartment comfort and window defrosting / dehumidification.

[0005] Methods with the features according to the preamble of claim 1 and according to the preamble of claim 5 are known from US 2009 / 0 118 090 A1.

[0006] Furthermore, Commission Regulation (EU) No 672 / 2010 describes conditions relating to outside temperature and vehicle running time that must be met during a warm-up phase of a hybrid powertrain system.

[0007] One object of the invention is to provide a method for controlling a hybrid powertrain system that minimizes the fuel consumption of an internal combustion engine while simultaneously meeting thermal requirements for a passenger compartment of a vehicle. SUMMARY

[0008] This problem is solved by a method having the features of claim 1.

[0009] The method is designed to control a hybrid powertrain system comprising an internal combustion engine and includes controlling the operation of the hybrid powertrain system in response to a trajectory of a preferred minimum coolant temperature for the internal combustion engine. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] One or more embodiments are now described by way of example with reference to the accompanying drawings, of which: Fig.1 represents a vehicle with a hybrid powertrain system coupled to a final drive and controlled by a control system, as disclosed; Fig. 2 represents a control scheme for controlling and regulating the operation of a hybrid powertrain system in response to a coolant temperature and a trajectory of a preferred coolant temperature according to the disclosure; Fig. 3 represents a temperature (in °C) based on a vehicle running time (in min) for a vehicle using a hybrid powertrain system according to the disclosure; Fig.4 according to the disclosure represents a basic characteristic map of an engine heat dissipation response, which includes basic operating costs for heat dissipation (in kW) determined with reference to engine operating points defined by the engine speed (in RPM) and the engine torque (Nm) for an internal combustion engine used in a hybrid powertrain system; Fig. 5 according to the disclosure represents a modified area of ​​the engine heat dissipation response, comprising modified operating costs for heat dissipation (in kW) determined with reference to engine operating points defined by the engine speed (in RPM) and the engine torque (in Nm) for an internal combustion engine used in a hybrid powertrain system; Fig.6 represents an exemplary scalar for the performance of a heating device with respect to a preferred minimum coolant temperature and a coolant temperature as a function of vehicle running time for an internal combustion engine used in a hybrid powertrain system according to the disclosure; Fig. 7 according to the disclosure represents a coolant temperature and a hysteresis temperature band for the preferred minimum coolant temperature based on the vehicle running time, which are determined for an internal combustion engine used in a hybrid powertrain system; and Fig. 8 according to the disclosure represents a coolant temperature and a modified hysteresis temperature band for the preferred minimum coolant temperature based on the vehicle running time, which are determined for an internal combustion engine used in a hybrid powertrain system. DETAILED DESCRIPTION

[0011] Referring now to the drawings, in which what is shown serves only to illustrate certain exemplary embodiments, and not to limit them, it shows Fig.Figure 1 schematically depicts a vehicle 5 with a hybrid powertrain system 20 comprising an internal combustion engine 40 and non-combustion torque motors 35 and 36 coupled to a transmission 50, which in turn is coupled to a final drive 60, all of which are controlled by a control system 10. The same reference numerals throughout the description refer to the same elements. The hybrid powertrain system 20 can be configured as a hybrid system (comprising a series hybrid system, a parallel hybrid system, or a compound hybrid system), as an extended-range electric vehicle (EREV) system, or as another powertrain configuration, without being limited to these. The vehicle 5 has an interior 80, which mainly comprises a passenger compartment for seating. The vehicle 5 with the hybrid powertrain system 20 serves for illustration, but not as a limitation.

[0012] The hybrid powertrain system 20 uses communication paths 55, paths 57 for mechanical power, and paths 59 for high-voltage electrical power. The paths 57 for mechanical power mechanically couple elements that generate, utilize, and / or transmit torque, and these include the internal combustion engine 40, the first and second electrically driven torque machines 35 and 36, respectively, the transmission 50, and the final drive 60. The paths 59 for high-voltage electrical power electrically connect elements that generate, utilize, and / or transmit high-voltage electrical power, and they include elements such as an energy storage device 25, a rectifier / inverter module 30, and the first and second electrically driven torque machines 35 and 36. The paths 59 for high-voltage electrical power include a high-voltage DC bus 29.The communication path 55 can include direct data transmission lines and high-speed data transmission lines to facilitate communication within the control system 10 and communication between the control system 10 and elements of the vehicle 5. The communication path 55 can include one or more direct analog connections, digital connections, serial peripheral interface buses (SPI buses), and high-speed communication buses 18, which may include a controller area network, i.e., a CAN bus.

[0013] The engine 40 is any internal combustion engine that converts fuel into mechanical power through a combustion process. The engine 40 is equipped with several detection devices and actuators designed to monitor operation and supply fuel to form a combustion charge to generate torque. One sensor of interest is a coolant temperature sensor 41, designed to monitor the operating temperature of the engine 40. The engine 40 is designed to operate as a spark-ignition engine, in which the timing of combustion and the associated engine torque are controlled by advancing or retarding the spark ignition timing. The engine 40 is designed as a spark-ignition direct injection (SIDI) engine, operating either in a spark-ignition combustion mode or in a controlled auto-ignition (HCCI) combustion mode.Alternatively, the engine 40 is configured to operate as a compression-ignition engine, with the timing of combustion and the associated engine torque controlled by advancing or retarding the timing of fuel injection events. The engine 40 is configured to execute auto-start and auto-stop control schemes and deceleration fuel cut-off (DFCO) control schemes during the operation of the vehicle system 5. By definition, the engine 40 is considered to be in an ON state when it is fueled and rotating, and in an OFF state when it is not fueled and not rotating. The engine 40 is also considered to be in a DFCO state when it is rotating but not fueled.

[0014] The first and second torque machines 35 and 36 comprise any non-combustion torque machines, and they preferably comprise multiphase electric motors / generators electrically connected to the rectifier / inverter module 30 and configured to convert stored electrical energy into mechanical power and to convert mechanical power into electrical energy that can be stored in the energy storage device 25. The first and second torque machines 35 and 36 have limitations regarding power outputs in the form of torque and rotational speeds.

[0015] The rectifier / inverter module 30 comprises a first and a second rectifier / inverter 32 and 33, which are electrically connected to the first and second torque machines 35 and 36, respectively. The first and second torque machines 35 and 36 interact with the corresponding first and second rectifier / inverter 32 and 33 to convert stored electrical energy into mechanical power and to convert mechanical power into electrical energy that can be stored in the energy storage device 25. The first and second electrical power rectifier / inverter 32 and 33 serve to convert high-voltage direct current electrical power into high-voltage alternating current electrical power and also to convert high-voltage alternating current electrical power into high-voltage direct current electrical power.The electrical power emanating from the first torque machine 35 can be electrically transmitted to the energy storage device 25 via the rectifier / inverter module 30 and the high-voltage bus 29, and to the second torque machine 36 via the rectifier / inverter module 30.

[0016] The transmission 50 preferably comprises one or more differential gear sets and actuable clutch components to effect torque transmission between the motor 40, the first and second torque machines 35 and 36, and an output element 62 coupled to the final drive 60. The transmission 50 is a two-mode transmission device configured to operate in conjunction with the first and second torque machines 35 and 36 to transmit torque via one of two or more discrete gear trains, designated as Mode 1 and Mode 2. The two or more discrete gear trains designated as Mode 1 and Mode 2 can comprise either a fixed-ratio operation, a continuously variable operation, or both.

[0017] The final drive 60 can comprise a differential gear unit 65, which is mechanically coupled to an axle 64 or, in one embodiment, to a half-shaft, which is mechanically coupled to a wheel 66. The differential gear unit 65 is coupled to the output element 62 of the hybrid powertrain system 20 and transmits output power between them. The final drive 60 transmits traction power between the transmission 50 and a road surface.

[0018] The energy storage device 25 can be any type of energy storage device, for example, a high-voltage battery. An example of an energy storage device 25 is a high-voltage battery made up of several lithium-ion cells. It can be seen that the energy storage device 25 can include several electrical cells, ultracapacitors, and other electrochemical devices configured to store energy and supply electrical power in a vehicle. If the energy storage device 25 is a high-voltage battery, it is connected via the high-voltage bus 29 to the rectifier / inverter module 30, which is connected to the first and second torque machines 35 and 36 to transfer electrical power between them.An electrical connection device 26 is connected to the high-voltage battery 25, and it is connectable to an external AC power source to supply electrical power for charging the high-voltage battery 25.

[0019] The control system 10 comprises a control module 12, which is connected via signaling to an operator interface 14. The operator interface 14 is used to refer to several human-machine interface devices through which the vehicle operator controls the operation of the vehicle 5. It can be seen that the human-machine interface devices may include, for example, an ignition switch to allow an operator to crank and start the engine 40, an accelerator pedal, a brake pedal, and a transmission range selector, i.e., PRNDL. Commands from the vehicle operator include a torque request (To) from the operator, which specifies a requirement regarding the magnitude of the traction torque delivered to the final drive 60 to effect vehicle acceleration. It can be seen that vehicle acceleration includes both positive and negative acceleration events.

[0020] The vehicle includes other systems and control schemes that can affect engine operation, engine coolant temperature, and electrical load. The vehicle system features a controllable HVAC system that makes thermal and electrical load demands in response to operator input. Other vehicle systems may include an exhaust gas heat recovery (EGHR) system. An example EGHR includes a first heat exchanger that transfers heat between the exhaust gas and the engine coolant, and a second heat exchanger that transfers heat between the engine coolant and a transmission fluid, with a fluid circuit that fluidically connects the first and second heat exchangers. Other vehicle systems may include a controllable, electrically operated heater for the passenger compartment. Other vehicle systems may include a controllable, electrically operated windshield dehumidifier.Other vehicle systems may include a controllable, electrically operated dehumidifier for the rear window.

[0021] The control module 12 is connected via signal transmission to detection devices for each of the energy storage device 25, the rectifier / inverter module 30, the first and second torque machines 35 and 36, the motor 40, and the gearbox 50. The control module 12 is functionally connected to actuators of the rectifier / inverter module 30, which comprises the first and second rectifiers / inverters 32 and 33, the motor 40, and the gearbox 50, either directly or via the communication bus 18, in order to control their operation according to executed control schemes, which are stored in the form of routines and calibrations.

[0022] For ease of representation, the control module 12 is depicted as a single, unified element. The control module 12 preferably has a distributed architecture comprising multiple control module units. The described functions, as performed by the control module 12, can be combined in one or more units, e.g., implemented in software, hardware, and / or an application-specific integrated circuit (ASIC), as well as in auxiliary circuits that are separate from and distinct from the control module 12. A master control module unit preferably controls and directs the operations of individual control modules of the distributed architecture, which are assigned to the individual control module units.The individual control modules can be assigned to the energy storage device 25, the rectifier / inverter module 30, the first and second torque machines 35 and 36, the motor 40, or the gearbox 50, and can be physically located in their vicinity to monitor and control their operation. Thus, the individual control module devices of the control module 12 can be directly connected to individual detection devices via signal transmission, and they can be directly functionally connected to individual actuators, including the energy storage device 25, the rectifier / inverter module 30, the first and second torque machines 35 and 36, the motor 40, and the gearbox 50, to monitor and control their operation.

[0023] Communications between the master control module and the individual control module units of the control module 12, and between the individual control module units and individual units of the energy storage device 25, the rectifier / inverter module 30, the first and second torque machines 35 and 36, the motor 40, and the gearbox 50, are executed using the communication paths 55, which comprise the communication bus 18. Transmitted messages can be in the form of sensor signals and actuator commands, using communication protocols assigned to the specific elements of the communication path 55, e.g., serial communication. The communication protocols for the high-speed communication bus 18 preferably include structured communication by periodically sending messages, for example, with a loop cycle of 12.5 ms.

[0024] It is evident that a control system exhibits delay times between a detected event and a corresponding response. These delay times can relate to and include sensor response times, sensor signal A / D conversion (if required), communication protocols for messages that include sender signals, controller analysis that includes the detection of an actuator response, communication protocols for messages that include actuator responses, and protocols associated with the execution of an actuator command. The delay times include those introduced due to the distributed architecture of Control Module 12. It is evident that any total delay time between a detected event and a corresponding response can be predictable, since the aforementioned delay times are measurable and predictable.A delay time of interest is a delay time between an instructed torque output from the first or the second electrically driven torque machine 35 or 36 and a corresponding change in the electrical power flow from the high-voltage energy storage device 25.

[0025] Monitored parameters of the motor 40 preferably include motor speed (Ne), motor torque or motor load (Te), and temperature. Monitored parameters of the gearbox 50 preferably include speeds, such as output speed (No), traction torque (To), and hydraulic pressures at multiple locations, from which parameters, including those for actuating special torque transmission clutches, can be determined. Monitored parameters of the first and second torque machines 35 and 36 preferably include speeds and power flows, e.g., the electrical current flow, from which electric motor torque commands (Tm) can be determined. Monitored parameters of the energy storage device 25 may include battery current and voltage (battery power), state of charge, and battery temperature.It is understandable that the monitored parameters can be measured directly, derived from direct measurements, or estimated in other ways.

[0026] Control module, module, control, controller, control unit, processor and similar terms mean any suitable or various combinations of an application-specific integrated circuit (ASIC) or several application-specific integrated circuits, an electronic circuit or several electronic circuits, a central processing unit or several central processing units (preferably a microprocessor or microprocessors) and associated memory and archive (read-only memory, programmable read-only memory, main memory, hard disk, etc.).), which execute one or more software or firmware programs, one or more logic circuits, one or more input / output circuits and devices, suitable signal conditioning and buffering circuits, and other suitable components that provide the described functionality. Software, firmware, programs, instructions, routines, code, algorithms, and similar terms mean any set of instructions executable by a controller, including calibrations and lookup tables. The control module has a set of control routines that are executed to create the desired functions. These routines are executed, for example, by the central processing unit and are used to monitor inputs from the detection devices and other control modules on the network, as well as to execute control and diagnostic routines to manage the operation of actuators.The routines can be executed at regular intervals during ongoing engine and vehicle operation, for example, every 3, 125, 6, 25, 12.5, 25, and 100 milliseconds. Alternatively, the routines can be executed in response to the occurrence of an event.

[0027] Fig. Figure 2 presents a control scheme 200 for controlling and regulating the operation of a hybrid powertrain system in response to a coolant temperature and a trajectory of a preferred coolant temperature. The control scheme 200 is described with reference to the vehicle 5, which has a hybrid powertrain system 20 according to Fig.2 is used, however, it can be seen that the control scheme 200 can be implemented without restriction in other hybrid powertrain systems. The control scheme 200 comprises the operation of the hybrid powertrain system 20 being controlled in response to a trajectory of a preferred minimum coolant temperature for the internal combustion engine.

[0028] Table 1 is a key for Fig. 2 provided, wherein the numerically designated blocks and the corresponding functions are set out as follows. Table 1 BLOCK BLOCK CONTENTS 202 Monitor outside air temperature, monitor vehicle runtime, monitor vehicle warm-up time, monitor operator torque request 204 Determine requirements for warm-up operation and stabilized operation 206 Determine the trajectory of the preferred minimum coolant temperature 208 Generate a hysteresis temperature band around the trajectory of the preferred minimum coolant temperature. 210 Execute control of the hybrid powertrain system in response to the trajectory of the preferred minimum coolant temperature. 212 Determine the difference between the preferred minimum coolant temperature and the coolant temperature. 214 Select scalar multiplier 216 Determine the basic characteristic map of the engine's heat dissipation response for the engine. 218 Adjust the basic characteristic map of the motor's heat dissipation response for the motor using the scalar multiplier. 220 Create a modified heat dissipation area for the engine. 222 Determine Tm and Te commands in response to the operator's torque request as a function of a customized Baseline engine power loss and hysteresis temperature band 224 Control other processes of the hybrid powertrain system and the vehicle system 230 Monitor coolant temperature

[0029] Monitored conditions of interest for the control scheme 200 include the outside air temperature, the vehicle running time, the vehicle warm-up time, and a torque request from an operator (202). The outside air temperature, the vehicle running time, and the vehicle warm-up time are used as indicators of the interior temperature 80 of a vehicle in question.

[0030] Requirements for warm-up and stabilized operation are determined (204), and they preferably include a trajectory of the preferred minimum coolant temperature, which comprises minimum coolant temperatures based on an elapsed operating time, associated with an initial warm-up phase and a stabilized phase for the vehicle in question. The operating phases are defined with reference to a vehicle running time. An exemplary set of requirements, which includes the trajectories of the preferred minimum coolant temperature for warm-up and stabilized operation, is given with reference to Fig. 3 shown. Fig.Figure 3 presents a data graph 300 showing a temperature (in °C) 305 relative to the vehicle runtime 310, which is an elapsed runtime (in min) for the vehicle 5, which uses a hybrid powertrain system 20. It can be seen that the engine runtime during the initial warm-up phase of operation corresponds to the vehicle runtime. The data graph 300 shows trajectories of the preferred minimum coolant temperature relative to the vehicle runtime for several ambient air temperatures, and it includes warm-up operation and stabilized operation for an exemplary vehicle. The trajectories of the preferred minimum coolant temperature are shown relative to the vehicle runtime for several ambient air temperatures, namely 20°C (312), 10°C (314), 0°C (316), -10°C (318) and -20°C (320). The trajectories of the preferred minimum coolant temperature shown are for a vehicle warm-up time of sufficient duration to allow the vehicle to reach stabilized temperatures, including a stabilized coolant temperature and a stabilized vehicle interior temperature. The data shown are for illustrative purposes only and are not limiting. Preferred adjustments to the trajectories of the preferred minimum coolant temperature exist to accommodate variations in coolant temperature and vehicle interior temperature for a vehicle warm-up time, or shorter vehicle warm-up times, for each of the several ambient air temperatures, including 20°C (312), 10°C (314), 0°C (316), -10°C (318), and -20°C (320).It can be understood that the trajectories of the preferred minimum coolant temperature are specific to the interior of a vehicle in question.

[0031] The ambient air temperature, vehicle running time, and vehicle warm-up time are used to select a trajectory of the preferred minimum coolant temperature, which is defined with respect to the vehicle running time and the ambient air temperature, e.g., ambient air temperatures of 20°C, 10°C, 0°C, -10°C, and -20°C, which preferably takes the vehicle warm-up time into account and which preferably uses the aforementioned trajectories of the minimum coolant temperature, which are defined with reference to Fig. Figure 3 (206) is shown. Preferably, interpolation schemes are carried out to determine a trajectory of the preferred minimum coolant temperature for outside air temperatures between 20°C, 10°C, 0°C, -10°C and -20°C.

[0032] A hysteresis temperature band is generated around the trajectory of the preferred minimum coolant temperature (208). The hysteresis temperature band is used to operate the hybrid powertrain system 20 in response to a torque request from an operator (222). The hybrid control scheme uses the hysteresis temperature band to control the occurrence of engine auto-stop events, engine auto-start events, and DFCO events.

[0033] A control system for the hybrid powertrain is implemented in response to the trajectory of the preferred minimum coolant temperature (210). The control system includes direct monitoring of the coolant temperature (230), preferably using a coolant temperature sensor. A difference between the coolant temperature and a preferred minimum coolant temperature corresponding to the vehicle running time is determined using the trajectory of the preferred minimum coolant temperature (212).

[0034] A scalar for the power of a heating device is determined, which corresponds to the difference between the preferred minimum coolant temperature and the coolant temperature for the given vehicle operating time (214). The magnitude of the scalar for the power of the heating device, which corresponds to the difference between the preferred minimum coolant temperature and the coolant temperature, can be determined using a nonlinear proportional control scheme, a proportional-integral control scheme, or another control scheme. Fig.Figure 6 presents an exemplary scalar for the power output of a heating device 630 with respect to a preferred minimum coolant temperature 610 and a coolant temperature 620 as a function of the vehicle running time 640 for an internal combustion engine 40 used in a hybrid powertrain system 20. The magnitude of the scalar for the power output of the heating device decreases ramp-wise from an initial high value and changes as a function of the difference between the preferred minimum coolant temperature 610 and the coolant temperature for the vehicle running time 620.

[0035] A basic engine heat dissipation response map is developed for the engine of the hybrid powertrain system (216). An exemplary basic engine heat dissipation response map is presented with reference to Fig.Figure 4 shows how engine heat dissipation through power loss is characterized as a function of operating points of engine speed / engine load. Fig. Figure 4 represents a basic characteristic map of the engine heat dissipation response, comprising several basic operating costs for heat dissipation (in kW) 430, which are determined with respect to the engine operating points defined by the engine speed (in RPM) 420 and the engine torque (in Nm) 410 for an internal combustion engine 40 used in the hybrid powertrain system 20. A lowest heat dissipation cost of nominally 0 kW occurs at a speed / load operating point with the greatest amount of heat dissipation. The heat dissipation can be in the form of coarse heat dissipation or heat dissipation combined with the engine power per fuel rate.

[0036] The basic characteristic map of the engine heat dissipation response, developed for the internal combustion engine, is multiplied by the scalar for the power of the heating device (218) to generate a modified heat dissipation response area (220), which, with reference to Fig. 5 is shown. Fig.Figure 5 represents a modified area 500 of the engine heat dissipation response, which includes operating costs (in kW) 530. These costs are determined by multiplying the base operating costs for heat dissipation (in kW) 430 and the heating device power scalar based on engine operating points defined by engine speed (in RPM) 520 and engine torque (in Nm) 510 for the internal combustion engine 20. The lowest heat dissipation cost of nominally 0 kW occurs at the speed / load operating point with the highest amount of heat dissipation. Therefore, the heating device power scalar is used to modify the base map of the engine heat dissipation response to assist the hybrid powertrain system in selecting engine operating points with higher heat dissipation rates.

[0037] By monitoring the difference between the preferred minimum coolant temperature and the actual coolant temperature, the control system's behavior is modified only when the coolant temperature is lower than the trajectory of the preferred minimum coolant temperature. The heating device's power scalar is adjusted to minimize the engine operation required to reach the preferred minimum coolant temperature. This operation facilitates a primary mode that optimizes fuel economy with minimal modification of engine operation to achieve the desired coolant temperature.

[0038] The modified area of ​​the engine power loss response (220) and the hysteresis temperature band generated around the trajectory of the preferred minimum coolant temperature (208), as well as the coolant temperature, are used to operate the hybrid powertrain system 20 in response to an operator torque request (222). Operation of the hybrid powertrain system 20 involves determining preferred torque commands for the engine 40 (Te) and for the non-combustion torque machines 35 and 36 (Tm) to generate an output torque transmission to the final drive 60, which responds to the operator's torque request, with the engine 40 generating sufficient heat to cause the coolant temperature to follow the trajectory of the preferred minimum coolant temperature within the hysteresis temperature band.Such an operation includes controlling the occurrence of engine auto-stop events, engine auto-start events, and DFCO events.

[0039] Torque management control schemes are used to determine preferred torque commands for the motor 40 (Te) and for the non-combustion torque machines 35 and 36 (Tm), which are combined in the transmission 50 to produce an output torque that is transferable to the final drive 60 and responds to the operator's torque request. The torque management control schemes balance the operating costs and corresponding output torque for the motor and the operating costs and corresponding output torques for the torque machines to determine preferred operating points for controlling the operation of the motor and torque machines in response to the operator's torque request. The preferred operating points correspond to those that achieve an output torque that responds to the operator's torque request while minimizing overall operating costs.The modified operating costs, measured in units of power (in kW), indicate higher operating costs at lower speed / load operating points and lower operating costs at higher speed / load operating points. Motors operate at higher heat dissipation rates at higher speed / load operating points. Therefore, the modified motor heat loss response area supports motor operation at higher speed / load points with correspondingly higher heat dissipation rates when the preferred minimum coolant temperature is greater than the coolant temperature.

[0040] It is understandable that when a difference between the preferred minimum coolant temperature and the coolant temperature is minimized or eliminated, the modified area of ​​the engine power loss response 500, which refers to Fig.Figure 5 shows a similarity to the basic map of the engine power loss response 400, which is based on Fig. 4 is shown, and that the hybrid powertrain control system controls operation to minimize fuel consumption without the need to consider achieving or maintaining the preferred coolant temperature.

[0041] The hysteresis temperature band generated around the trajectory of the preferred minimum coolant temperature is used in the hybrid control scheme to operate the hybrid powertrain system 20 to control the occurrence of engine auto-stop events, engine auto-start events and DFCO events, to limit the engine's auto-stop and auto-start activity and to allow DFCO events. Fig.Figure 7 represents the coolant temperature 710 and a hysteresis temperature band 725 for the preferred minimum coolant temperature based on the vehicle running time 715, which are determined for an internal combustion engine 40 used in a hybrid powertrain system 20. The hysteresis temperature band 725 includes an upper preferred minimum coolant temperature 720 and a lower preferred minimum coolant temperature 730. An auto-stop allow command 740 is shown. As indicated, the auto-stop allow command 740 is initially disabled (0), and the internal combustion engine operates after a cold start event with an increasing coolant temperature 710. The auto-stop allow command 740 is only enabled (1) after the coolant temperature 710 exceeds the upper preferred minimum coolant temperature 720, thereby allowing engine auto-stop events and DFCO events.Engine auto-stop events and DFCO events are not allowed if the auto-stop allow command 740 is disabled (0).

[0042] The auto-stop allow command 740 is subsequently deactivated (0) only after the coolant temperature 710 is lower than the lower preferred minimum coolant temperature 730. Simultaneously with the deactivation (1) of the auto-stop allow command 740, the internal combustion engine is instructed to enter the ON state. As indicated, the size of the hysteresis temperature band 725 for the preferred minimum coolant temperature increases with the engine running time 715, as the vehicle transitions from the warm-up phase of operation to the stabilized phase of operation.

[0043] The hysteresis temperature band can be modified in response to vehicle speed to reduce the occurrence of engine auto-start events at low vehicle speeds and under stop / idle conditions. Fig.Figure 8 represents the coolant temperature 810 and a modified hysteresis temperature band 825 for the preferred minimum coolant temperature based on the vehicle running time 815, which are determined for an internal combustion engine 40 used in a hybrid powertrain system 20. The modified hysteresis temperature band 825 comprises an upper preferred minimum coolant temperature 820, a lower preferred minimum coolant temperature 830, and a modified lower preferred minimum coolant temperature 835. The vehicle speed 850 is shown. An auto-stop allow command 840 and an auto-stop activation command 870 are shown. The modified lower preferred minimum coolant temperature 835 decreases in direct relation to the vehicle speed 850.

[0044] The auto-stop allow command 840 is initially disabled (0), and the auto-stop enable command 870 is disabled (0) during engine warm-up. The auto-stop allow command 840 is enabled (1) when the coolant temperature 820 exceeds the upper preferred minimum coolant temperature 820, thereby permitting auto-stop operation. The auto-stop enable command 870 is enabled in response to a torque request from an operator, indicated by a reduction in vehicle speed. The engine performs an auto-stop in response to an allow (1) of the auto-stop enable command 870.The auto-stop allow command 840 is subsequently deactivated (0) only after the coolant temperature 810 falls below the lower preferred minimum coolant temperature 830, or only after the coolant temperature 810 falls below the modified lower preferred minimum coolant temperature 835 when the vehicle is traveling at low speed, e.g., less than 15 km / h, or when the vehicle is stationary. This is shown at 860. Under low-speed vehicle conditions, the auto-stop enable command 840 is deactivated if the coolant temperature 810 does not fall below the modified lower preferred minimum coolant temperature 835, which may be 6°C to 9°C lower than the lower preferred minimum coolant temperature 830.

[0045] Therefore, the control system will not execute an autostart event if the vehicle speed is in the low-speed or idle range until the coolant temperature 810 is less than the modified lower preferred minimum coolant temperature 835, for which an example is given at 860.

[0046] The auto-stop activation command 870 is only deactivated (0) after the coolant temperature 810 is lower than the modified lower preferred minimum coolant temperature 835. The internal combustion engine is instructed to operate with the deactivation (0) of the auto-stop allow command 840 and the deactivation (0) of the auto-stop activation command 870 simultaneously, even if it is at the modified lower preferred minimum coolant temperature 835.

[0047] The operation of the hybrid powertrain system 20 and other vehicle and powertrain systems that affect engine operation, coolant temperature, and electrical load are controlled in response to operator commands and individual control schemes (224), and the coolant temperature is directly monitored, preferably using the coolant temperature sensor (230). Exemplary vehicle and powertrain systems that affect engine operation, coolant temperature, and electrical load include the previously mentioned controllable HVAC system, the EGRH configured to transfer heat between the exhaust gas, engine coolant, and transmission fluid, the controllable electrically operated passenger compartment heater, the controllable electrically operated windscreen dehumidifier, and the controllable electrically operated rear window dehumidifier.

[0048] The disclosure has described certain preferred embodiments and their modifications. Further modifications and changes may become apparent to others while reading and understanding the description. It is therefore intended that the disclosure is not limited to the specific embodiment or embodiments disclosed as the best way considered for carrying out this disclosure, but rather that the disclosure will encompass all embodiments that fall within the scope of the appended claims.

Claims

[1] Method for controlling a hybrid powertrain system (20) comprising an internal combustion engine (40), the method comprising controlling the operation of the hybrid powertrain system (20) in response to a trajectory of a preferred minimum coolant temperature for the internal combustion engine (40), wherein controlling the operation of the hybrid powertrain system (20) comprises performing control of the hybrid powertrain system (20) in response to the trajectory of the preferred minimum coolant temperature for the internal combustion engine (40) and in response to an engine coolant temperature, characterized by , that several trajectories (312, 314, 316, 318, 320) of the preferred minimum coolant temperature comprise minimum coolant temperatures related to a vehicle running time (310) that are associated with an initial warm-up phase of operation and a stabilized phase of operation, An outside air temperature, the vehicle running time (310) and a vehicle warm-up time are used to select the trajectory of the preferred minimum coolant temperature from the several trajectories (312, 314, 316, 318, 320), and The execution of the control of the hybrid powertrain system (20) includes: a basic characteristic map of an engine heat dissipation response for the internal combustion engine (40) is adapted with a scalar multiplier, which is determined with reference to a difference between the trajectory of the preferred minimum coolant temperature for the internal combustion engine (40) and the engine coolant temperature, wherein the basic characteristic map of the engine heat dissipation response includes basic operating costs (430) for heat dissipation, which are determined with reference to engine operating points defined by an engine speed (420) and an engine torque (410) for the internal combustion engine (40), and wherein the scalar multiplier is adjusted to minimize the operation of the internal combustion engine (40) associated with achieving the preferred minimum coolant temperature; and The operation of the internal combustion engine (40) is controlled to generate heat in order to ensure that the coolant temperature follows the trajectory of the preferred minimum coolant temperature. [2] Method according to claim 1, wherein the trajectory of the preferred minimum coolant temperature lies within a hysteresis temperature band (725). [3] Method according to claim 2, wherein the hysteresis temperature band (725) comprises an upper preferred minimum coolant temperature (720) and a lower preferred minimum coolant temperature (730). [4] Method according to claim 3, wherein the lower preferred minimum coolant temperature (730) is modified in response to a vehicle speed.

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