DE102011114230B4 - Method and system for controlling a flying machine start for a hybrid system - Google Patents

Abstract

A method for controlling a flying machine start in a drive train (5), which comprises an electric motor (20), which provides a propulsion torque on a transmission input shaft (52), an internal combustion engine (10) and an engine separation clutch (54) which selectively transmits torque between the Machine (10) and the engine (20), the method comprising: a desired input speed is monitored; a synchronization speed is determined based on the desired input speed; an output torque request is monitored; a propulsion torque on the transmission input shaft (52 ) is determined on the basis of the output torque request; a compensation torque, which is to be provided at the engine separation clutch (54) for the on-the-fly engine start, is determined on the basis of an engine activation speed profile, which is determined on the basis of the synchronization speed; the motor (20) is controlled is to a mot to provide order torque based on a sum of the propulsion torque and the compensation torque; wherein determining the engine activation speed profile comprises: during a first stage the compensation torque accelerates the engine (10) from a stopped state to an engine ignition speed; during a second stage the engine torque for accelerating the machine (10); during a third stage following the second stage, only the compensation torque controls the machine (10) to the synchronization speed, the machine torque decreasing again to zero during the third stage; andduring a fourth stage, the machine disconnect clutch is locked.

Description

TECHNICAL AREA

This invention relates to a method of controlling a flying machine start in a drive train that includes an electric motor providing propulsion torque to a transmission input shaft, an internal combustion engine, and an engine disconnect clutch that selectively provides torque transfer between the engine and the engine.

Such a method is based, for example, on the type DE 10 2007 052 737 A1 emerged. There, the machine torque is steadily increased while the clutch is engaged, while the torque of the electric motor decreases accordingly in return.

BACKGROUND

Hybrid unit drive trains are known which comprise several torque-generating devices. For example, a powertrain can include an internal combustion engine and an electric motor, and the engine and motor can be controlled to increase overall vehicle efficiency, for example by using the motor in an operation that is efficient for the motor, the machine is used in an operation that is efficient for the engine, both devices are used to cooperatively provide torque, if such operation is efficient, and the motor is used to store energy in an energy storage device, for example during braking of the vehicle or by pulling torque from the machine.

In an exemplary embodiment, the machine and the motor each provide torque to the drive train. In another exemplary embodiment, the machine is delivering torque to the engine and the engine, in turn, is delivering torque to the remainder of the drive train.

Methods are known for shutting down the engine when it is not in use to save the fuel that would be consumed by otherwise idling or driving the engine at low speed. When the machine is shut down, a shaft leading from the machine to the drive train will either stop rotating, which will require the rest of the drive train to align with the non-moving shaft, or the rest of the drive train will need torque to rotate the shutdown machine, overcoming the torque (due to friction, cylinder pumping forces, etc.) required to rotate the machine. A clutch device can be applied between the machine and the rest of the drive train to allow the machine to remain off and stopped while the rest of the drive train continues to operate.

Coupling devices or clutches are used to selectively connect or disconnect shafts that are capable of transmitting torque. Clutches can be operated in a number of manners known in the art. For example, hydraulic pressure can be used to operate a clutch. An exemplary switching between states controlled by a pair of clutches requires that one clutch be unloaded, allowing two shafts that were previously coupled to rotate freely from one another and then loading another clutch, two Waves that were previously decoupled or free to revolve relative to each other. Hydraulically operated clutch devices often include clutch plates that are spring loaded to an initial decoupled position, where hydraulic pressure applied to a piston applies pressure that overcomes the bias of the spring to bring the plates into a coupled position.

Machines may include a dedicated starter motor that supplies torque to the machine to allow the normal combustion cycle of the machine to take over. Torque to start the machine can be drawn from the drive train or the associated motor of the drive train. A hybrid power plant powertrain can include multiple motors, where one motor can be used to provide torque to the remainder of the powertrain to propel a vehicle, while the other motor can be used to start the engine.

Hybrid powertrains may include a planetary gear set to manage the transfer of torque through the powertrain. Planetary gear sets are mechanisms known in the art that include three gears or groups of gears. According to an exemplary In the embodiment, a sun gear is located in the center of the planetary gear set, a ring gear is located concentrically with the sun gear, and planet gears rotate between the sun gear and the ring gear, with teeth of each of the planet gears in constant contact with teeth of the sun gear and the ring gear. Three planet gears are an exemplary number of planet gears. The planetary gears can be connected by a planetary gear carrier that allows all planetary gears to rotate individually, but since the planetary gears are driven around the axis of the planetary gear set, they drive the planetary gear carrier, thereby applying torque to a shaft connected to the planetary gear carrier becomes. The same applies in reverse operation that a torque can be applied to the planetary gear carrier, whereby one or both of the other gears of the planetary gear set are driven. Torque applied to one gear or set of gears is transferred to the remaining gears. Torque can be applied to two gears or a set of gears to drive the third gear or set of gears.

The invention is based on the DE 10 2007 052 737 A1 The basic task is to ensure that the machine is switched on smoothly.

SUMMARY

This object is achieved with a method having the features of claim 1.

A powertrain includes an electric motor that provides propulsive torque to a transmission input shaft, an internal combustion engine, and an engine disconnect clutch that selectively provides torque transmission between the engine and the engine. A method for controlling an on-the-fly engine start in the drive train comprises that an output torque request is monitored, a propulsion torque on the transmission input shaft is determined on the basis of the output torque request, a compensation torque that is to be provided at the engine separation clutch for the on-the-fly engine start is determined, and the engine is controlled to provide engine torque based on a sum of the propulsion torque and the compensation torque.

Figure list

• 1 einen beispielhaften Hybridaggregat-Antriebsstrang gemäß der vorliegenden Offenbarung veranschaulicht;
• 2 ein beispielhaftes Steuermodul zum Ausführen eines fliegenden Maschinenstarts gemäß der vorliegenden Offenbarung veranschaulicht;
• 3 vier Stufen eines beispielhaften EDC-Steuerverfahrens gemäß der vorliegenden Offenbarung veranschaulicht;
• 4 einen beispielhaften fliegenden Maschinenstart, einschließlich zugehörige Drehzahlen und Drehmomente inklusive gemäß der vorliegenden Offenbarung veranschaulicht;
• 5 die Steuerung des Kupplungsdrucks auf der Basis eines Kupplungsdruckbefehls gemäß der vorliegenden Offenbarung veranschaulicht;
• 6 eine beispielhafte EDC-Druck-zu-Drehmoment-Optimalwertkompensation gemäß der vorliegenden Offenbarung veranschaulicht;
• 7 einen beispielhaften Antriebsstrang, der eine Getriebeausgangskupplung umfasst, gemäß der vorliegenden Offenbarung veranschaulicht;
• 8 einen beispielhaften Antriebsstrang, der eine Getriebeausgangskupplung umfasst, die innerhalb eines Getriebes benutzt wird, gemäß der vorliegenden Offenbarung veranschaulicht;
• 9 einen beispielhaften fliegenden Maschinenstart einschließlich eines Modulationsdrucks für eine Getriebeausgangskupplung gemäß der vorliegenden Offenbarung veranschaulicht;
• 10 einen beispielhaften fliegenden Maschinenstart einschließlich eines Verbrennungsunterstützungsverfahrens gemäß der vorliegenden Offenbarung veranschaulicht;
• 11 einen beispielhaften fliegenden Maschinenstart, der die Nutzung von Drehmoment von der Maschine umfasst, um eine Synchronisationsdrehzahl zu erreichen, gemäß der vorliegenden Offenbarung veranschaulicht; und
• 12 einen beispielhaften Prozess zum Ausführen eines fliegenden Maschinenstarts gemäß der vorliegenden Offenbarung veranschaulicht.

One or more embodiments will now be described, by way of example, with reference to the accompanying drawings, in which:

• 1 illustrates an exemplary hybrid powertrain according to the present disclosure;
• 2 illustrates an exemplary control module for performing an engine flying start in accordance with the present disclosure;
• 3 illustrates four stages of an exemplary EDC control method in accordance with the present disclosure;
• 4th illustrates an exemplary engine on-the-fly, including associated speeds and torques, in accordance with the present disclosure;
• 5 illustrates control of clutch pressure based on a clutch pressure command in accordance with the present disclosure;
• 6th illustrates an exemplary EDC pressure-to-torque feed forward compensation in accordance with the present disclosure;
• 7th illustrates an exemplary powertrain including a transmission output clutch in accordance with the present disclosure;
• 8th illustrates an exemplary powertrain including a transmission output clutch used within a transmission in accordance with the present disclosure;
• 9 illustrates an exemplary engine on-the-fly including modulation pressure for a transmission output clutch in accordance with the present disclosure;
• 10 illustrates an exemplary engine on-the-fly including a combustion assist method in accordance with the present disclosure;
• 11 illustrates an exemplary engine on-the-fly start including utilizing torque from the engine to achieve a synchronization speed in accordance with the present disclosure; and
• 12th Illustrates an exemplary process for performing an engine on the fly in accordance with the present disclosure.

DETAILED DESCRIPTION

Referring now to the drawings, in which the showings are for the purpose of illustrating certain exemplary embodiments only 1 an exemplary hybrid power train. Powertrain 5 includes machine 10 , Engine 20th , Energy storage device 30th and gear mechanism 40 . Powertrain 5 can optionally have a second motor 62 that transmits torque directly to the machine. An engine output shaft 50 is with an engine input shaft 52 by a coupling device 54 connected. When the coupling device 54 is in an engaged state and there is no slippage within the clutch device, the engine output shaft runs 50 at the same rate as the motor input shaft 52 around, and torque can be between the machine 10 and the engine 20th be transmitted. When the coupling device 54 is disengaged or is in a disengaged state, the machine can 10 at a different rate from the engine 20th turning or is from the engine 20th separated, or the machine 10 can be shut down without running the engine 20th to influence. When the coupling device 54 is disengaged, the engine can 20th used to apply torque to the output shaft 56 through the gearbox 40 regardless of whether the machine is to be delivered 10 is in a working state or a shutdown state. The machine 10 is illustrated in such a way that it is represented by waves 50 and 52 and coupling device 54 directly to the engine 20th connected is. Coupling device 54 can be referred to as a machine disconnect clutch (EDC). The coupling device 54 In an exemplary embodiment, comprises a hydraulically operated clutch, on which hydraulic pressure can be controlled in such a way that the torque capacity is varied, and varying slip levels can be achieved via the clutch device 54 be made possible and controlled. It should be noted that a number of powertrain configurations are possible, including, for example, the use of planetary gear sets to vary the manner in which the machine operates 10 and the engine 20th interact and torque to the drive train 5 deliver. The coupling device 54 can exist between two waves, as shown in 1 is illustrated. Other embodiments are contemplated, for example with a gearbox 40 , which includes a brake clutch connected to a member of a planetary gear set and controls how torque through the planetary gear set on the output shaft 56 is transmitted. In another embodiment, multiple motors can deliver torque to the output through the transmission while one or both are connected to the machine. A number of example powertrain embodiments and configurations are contemplated for working with the methods disclosed herein, and the disclosure is not intended to be limited to the particular example embodiments set forth herein.

An engine on-the-fly includes an engine that is initially stationary and deactivated, taking torque from the remainder of the powertrain to accelerate the engine, and then starting the engine. In the course of a flying machine start, a previously separated machine is accelerated from an initial speed of zero to a speed that is synchronous with a speed of another shaft, or to a synchronous speed ( _{Ne_synch} ), so that one clutch connects the machine to the other Shaft connects, can be locked and the machine can deliver torque to the rest of the drive train. In one embodiment in which the clutch adapts a machine _speed to an input _speed , the _{Ne_synch} value that the machine must adapt is the input _speed . If the speed that needs to be adjusted is a dynamic profile, for example an accelerating input speed, then _{Ne_synch needs} to be determined based on factors that affect the operation of the powertrain. An example factor is an ability of the machine to accelerate from a stop to a given speed with acceptable parameters. For a given input _{speed profile} and machine with known properties, N _{e_synch} can be _determined by calibration, computation, modeling, or any method sufficient to accurately predict the operation of the machine, clutch and the rest of the drive train, and a number of calibration curves or Prediction modifiers can be used for different conditions and operating ranges. N _{e_synch} supplies a speed that the machine must reach in order to complete the machine start on the fly. If the adjusted shaft speed is steady, then the machine can have flexibility in reaching N _{e_synch} . If the adapted shaft speed is dynamic, then it will be necessary for the machine to _{reach Ne_synch} at a particular point in time in order to avoid drivability _problems when the machine _starts on the fly. N _{e_synch} can be used to indicate a time at which the machine started must be, and to determine an acceleration that the machine must achieve so that the machine reaches N _{e_synch} at a correct point in time. Such a start time for the machine and the required acceleration of the machine can be implemented as a target machine activation speed profile.

A number of methods can be used to control the machine 10 to start from a switched-off state into an operating state. A machine start on the fly can start the machine 10 and transition from the switched-off state to an operational state while the engine is running 20th Torque to the gearbox 40 supplies. According to an exemplary embodiment, an on-the-fly engine start can be achieved by the clutch device 54 is engaged, reducing torque from the engine device 20th the machine 10 is fed and the machine 10 is rotated so that the combustion cycle can begin. However, it will be found that such an engagement of the clutch device 54 while engine 20th Torque to the gearbox 40 can produce a noticeable change in the torque applied to the output shaft 56 and the associated final drive is provided or adversely affects drivability.

Control modules can operate the machine 10 , of the motor 20th , of the motor 62 , the transmission 40 and the coupling device 54 Taxes. Control methods can be applied by the control modules, which synchronize the operation of the different devices in order to maintain the drivability of the overall drive train. Control module, module, controller, controller, control unit, processor and similar terms mean any of or various combinations of one or more of an application specific integrated circuit (s), an electronic circuit (s), a central processing unit (s) , (preferably a microprocessor / microprocessors) and associated memory and storage device (read-only, programmable read-only, direct access, hard disk, etc.) that executes one or more software or firmware programs or routines, a combinatorial logic circuit / combinatorial logic Circuits, an input / output circuit and an input / output device / input / output circuits and input / output devices, suitable signal conditioning and buffering circuit and other components, and the like m to provide the functionality described. Software, firmware, programs, instructions, routines, code, algorithms, and the like mean any set of instructions executable by a controller, including calibrations and look-up tables. The control module has a set of control routines that are executed to provide the desired functions. Routines are executed, such as by a central processing unit, and are operable to monitor inputs from detection devices and other networked control modules and to execute control and diagnostic routines to control the operation of actuators. Routines can be executed based on events or at regular intervals, for example, every 3.125, 6.25, 12.5, 25 and 100 milliseconds, during ongoing machine and vehicle operation.

Driveability can be adversely affected by abruptly engaging an EDC with an engine that is already supplying torque to a transmission. The motor, based on a motor torque command, draws an amount of power from an associated energy storage device based on the torque that the motor is expected to deliver to the transmission. Engaging the EDC while the engine continues to draw the same amount of power results in the same torque output from the engine that is shared between the transmission and the engine. A desired engine activation speed profile can be determined for a particular flying engine start, so that the expected operation of the machine can be determined through the engine start. Controlling a drive train through an on-the-fly engine start includes determining an engine torque that is required to provide a target torque to the transmission, determining an engine torque that will be required by the EDC, which provides the necessary cranking torque on the engine to perform the engine on-the-fly start and the engine is controlled by the engine torque that will be required by the EDC, which provides the necessary torque to the engine, and the engine torque that is required to achieve the target Provide torque to the transmission, are summed.

According to one embodiment, an on-the-fly engine start can include the application of torque to a machine by an EDC, which allows the EDC to be controlled, for example on the basis of a comparison of an actual engine speed with a machine speed profile for the on-the-fly engine start, in order to ensure controllability of the clutch and includes controlling the EDC with PI curve fitting based on solenoid current and steady state clutch pressure feedback. A testing, estimating, or modeling of the EDC clutch pressure by an on-the-fly Engine start through can be used to determine a required engine torque necessary to compensate engine load on the EDC, or an engine compensation torque while the engine is being rotated. In one embodiment, torque required to rotate the engine through, for example, engine on-the-fly, as determined by testing, estimating, or modeling, can be used to determine or estimate a compensation torque that is required to supply the torque required to rotate the machine. Determining the compensation torque may include using a clutch pressure torque model to estimate a reaction torque in the EDC. In addition, a pressure-torque compensation model can be used to compensate for non-linearity, time lag, and temperature effects present in a hydraulic pressure measurement. In one embodiment, a controlled EDC torque may be controlled based on a feedforward calculation of machine inertia, friction, and compression torque. Machine inertia can be calculated based on a calibrated machine acceleration profile. In one embodiment, propulsion torque can also be controlled or smoothed using a modulated pressure on a transmission output clutch. Slipping the transmission output clutch isolates the downstream driveline from vibrations that occur due to an imperfectly compensated disturbance during the on-the-fly engine start event, which allows slippage when torque applied to the transmission output clutch exceeds a selected value.

2 FIG. 11 schematically illustrates an exemplary control module for performing an engine on-the-fly. The control module 100 for a flying engine start includes a summation block 110 , which is an engine torque that is required to drive the final drive, or a propulsion _torque (T _{m_propel} ) 138 and required engine torque that is necessary to compensate engine _load on the EDC by a flying engine start, or an engine compensation _torque (T _{m_comp} ) 136 summed and a motor torque _command (T _{m_cmd} ) 146 to a motor converter 120 outputs that controls an associated motor. A control module 100 A control module can also be used for a flying machine start 240 for active driveline damping that include a signal 144 based on reducing torque fluctuation in the output torque to summation module 110 supplies. The control module 100 may receive input from the engine control module regarding required engine torque generation, or the control module 100 can calculate the required machine torque generation directly.

The illustrated control module 100 for a flying machine start determines a number of terms in support of T _{m_comp} 136 . An engine speed profiling module 140 determines a machine speed profile for the flying machine start, which is a target machine acceleration 108 (N _{edot_ref} ) and a target machine _speed 112 (N _{e_ref} ) based on an actual engine _speed 106 and a current output speed of the transmission output or a current output speed 104 . N _{edot_ref} 108 and N _{e_ref} 112 are used in an EDC torque _{control module} 150 used to provide an EDC torque control term 116 or determine a clutch control term. N _{e_ref} 112, the actual engine _speed 106 and the actual engine torque 114 are in an EDC slip control module 160 used to provide an EDC torque control term 118 or clutch control term. The EDC torque control term 116 and the EDC torque control term 118 are in summation module 220 summed with an EDC torque command 122 is formed. The EDC torque command 122 is based on torque and pressure properties of the EDC in the module 170 converted to the EDC print command 124 to determine. The EDC print command 124 is printed with an actual EDC 128 in the pressure regulation module 180 compared with closed loop control. The actual EDC pressure 128 can be a measured value as measured by a pressure transducer or the actual EDC pressure 128 can be an estimate. The pressure regulation module 180 Closed loop uses a difference to the EDC 54 to control. The EDC 54 may be present as a separate device in the drive train. In one embodiment, the EDC 54 be part of the transmission and / or be controlled with it. The actual EDC pressure 128 is from the clutch pressure-torque model 200 used to be a reaction torque 132 in the EDC 54 appreciate. It also uses the pressure-torque compensation model 205 the actual EDC pressure 128 to set a torque compensation value 134 for non-linearity, time delay and temperature effects. Reaction torque 132 and the torque compensation value 134 are in summation module 215 summed to an EDC torque estimate 148 to build. The clutch torque compensation module 210 uses the EDC torque estimate 148 to get T _{m_comp} 136 to determine. The propulsion torque control module 130 monitors the current output speed 104 and the output torque request 102 to enter the machine torque command 142 and T _{m_propel} 138 to determine. The summation module 110 summed up T _{m_comp} 136 , T _{m_propel} 138 and signal 144 to T _{m_cmd} 146 for controlling the engine or engines of the vehicle. The control module 100 For engine on-the-fly, an exemplary embodiment of a control module provides for performing the disclosed methods, however, it should be understood that a number of different embodiments of control modules may be used and that the disclosure is not intended to be limited to the exemplary embodiment disclosed herein.

Hydraulic pressure to the EDC or other clutches may be a function of controlling a main hydraulic pump, often associated with the input speed of the transmission, and an auxiliary pump. Controlling the main and auxiliary pumps and the hydraulic pressure delivered to the system that controls the clutches may include monitoring discharge pressures from one or the other pump and regulating the pressure on the system accordingly. Clutches include clutch fill events using control methods known in the art to bring an unfilled clutch to a point where it is ready to apply pressure to the associated clutch facings, or the point of contact of the clutch. Such a point may be referred to as the point of onset torque in the clutch.

3 illustrates four stages into which an exemplary method of controlling an EDC can be broken down. In a top portion of the figure, a horizontal axis illustrates a time period in seconds, and a vertical axis illustrates a rotational speed in revolutions per minute. It's an engine speed 290 , an engine speed 291 and an EDC speed difference 292 showing a speed difference or slip between the plates of the clutch or the difference between the machine speed 291 and a transmission input speed is illustrated. In a lower portion of the figure, a horizontal axis corresponds to the same time period as illustrated in the upper portion, and a vertical axis illustrates torque in Newton meters. It is a machine torque command 293 , a torque transmitted through the EDC, or clutch torque 294 , and an engine torque command 295 illustrated. Stage A 250 is a machine turning stage at which the machine torque command 293 Is zero and the EDC is engaged to rev up the engine. The engine torque command 295 is increased by the clutch torque 294 based on an EDC clutch torque estimate. In stage B 260, the engine has fired and engine torque commands 293 are used to get the machine speed 291 bring close to synchronization in a control mode. Together with the control of the machine torque, the EDC is subject to slip regulation to a target EDC speed difference 292 between the machine speed 291 and the engine speed 290 and the associated transmission input speed. In step C 270 is the engine speed 291 close to the transmission input speed, and the EDC speed difference 292 , representing EDC slip, is reduced to the desired minimum level by clutch slip control at minimum commanded engine torque. This is to minimize engine torque torsional disturbances on the driveline when the EDC is locking. In stage D 280, the EDC is blocked and the machine torque 293 is increased when the engine torque 295 is decreased, thereby completing the engine start-up sequence.

3 graphically illustrates one embodiment of a machine start-up on the fly, including associated speeds and torques. As in the upper section of 3 may be the engine speed 290 remain unaffected by the flying machine start. A machine speed 291 starts at zero initially and goes through steps A 250 (starting the machine), B 260 (increasing the machine speed) and C 270 (synchronization) in order to achieve operation at the same speed in step D 280. A motor torque is initially 100 Nm, a value which in this example is required to be provided to the transmission in order to drive the final drive forward (eg on the basis of an output torque request). In stage A 250 is clutch torque 294 increased to provide a torque required to start rotating the machine. The engine torque 295 becomes during the increase in clutch torque 294 increased so that torque can be fed to the EDC without interrupting the 100 Nm that must be delivered to the transmission to drive the final drive. Through stage B 260 the machine is in an operating mode. The EDC can be partially or fully disengaged, reducing or eliminating the engine torque delivered to the machine. Through stage B 260, the machine increases speed based on torque supplied by the machine. In step C 270, the EDC is re-engaged, engine torque 293 is dropped to or near zero, and engine torque 295 is increased again, so that the engine has the remaining increase in engine speed 291 can control which is required to the engine speed 291 with the engine speed 290 to synchronize. One skilled in the art will find that the motor is capable of finer control with a shorter delay time than the machine, and that the motor control through stage C. 270 provides a smoother transition through it. Finally can in level D 280 Machine torque and engine torque according to a target operation in the steady state, both devices are determined on the basis of an overall target operation of the drive train.

wobei T_{edc_ol} der Steuerungsabschnitt des Kupplungsdrehmoments ist,
T_gas das Gasverdichtungsdrehmoment ist,
I_inertia das Trägheitsmoment für die Maschine ist,
α_{eng profile} eine Winkelbeschleunigung ist, die für die Maschine erforderlich ist.Throughout the process of flying machine start using a slip clutch, the EDC torque capacity is commanded to overcome the moment of inertia associated with the target machine acceleration profile and the gas compression torque during the machine cranking stage, and the engine torque must be compensated for the EDC load while the commanded propulsion torque is provided to the vehicle. In Step A, before locking of the EDC, the clutch torque T _EDC, the engine torque T _{m_cmd} and the engine torque T may _{e_cmd} be determined as follows: $${\text{T}}_{\text{edc\_ol}}={\text{T}}_{\text{gas}}+{\text{I.}}_{\text{inertia}}*{\mathrm{\alpha }}_{\text{closely}\text{.profile}}$$

where T _{edc_ol is} the clutch _torque control section,
T _{gas is} the gas compression torque,
I _{inertia is} the moment of inertia for the machine,
α _{tight profile is} an angular acceleration required by the machine.

wobei T_PID ein Proportional-Integral-Differential-Reglerausgang auf der Basis von N_{edot_ref} 108, N_{e_ref} 112 und der Ist-Maschinendrehzahl 106 ist.Equation 1 may additionally include a friction torque term. A control section of the clutch _torque T _{edc_cl} can be expressed as follows: $${\text{T}}_{\text{edc\_cl}}={\text{T}}_{\text{PID}}$$

where T _{PID is} a proportional-integral-derivative _{controller output} based on N _{edot_ref} 108, N _{e_ref} 112, and the actual engine _speed 106 is.

Once T _{edc_ol} and T _{edc_cl are} determined, T _edc can be determined as follows. $${\text{T}}_{\text{edc}}={\text{T}}_{\text{edc\_ol}}+{\text{T}}_{\text{edc\_cl}}$$

Like it in conjunction with 2 is disclosed, T _{m_cmd} can be determined as follows. $${\text{T}}_{\text{m\_cmd}}={\text{T}}_{\text{m\_propel}}+{\text{T}}_{\text{m\_comp}}$$

In one embodiment, T _{m_comp} can be _expressed as a monitored torque transmitted by the EDC, T _{edc_actual} . During stage A, the machine starts at a machine speed of zero and is not ready for operation. At some point at or near the transition from Stage A to Stage B, the engine will reach a speed at which the engine can become operational, can burn a charge, and can deliver engine torque. During Stage B, the EDC can be partially or fully disengaged to prevent engine torque from affecting the total torque transmitted to the final drive when the EDC is locked. The engine torque is commanded as shown in Equation 5 such that the engine torque is less than or equal to the torque necessary for the engine speed to follow the commanded machine profile. This is done to prevent the engine speed from overshooting the target speed profile. Similar to Equation 1, Equation 5 may additionally include a friction torque term. $${\text{T}}_{\text{e\_cmd}}\le {\text{T}}_{\text{gas}}+{\text{I.}}_{\text{inertia}}*{\mathrm{\alpha }}_{\text{closely}\text{.profile}}$$

The effect of different machine start positions can be used to control T _edc and T _{m_cmd} when stage A is initiated. The clutch torque controller must increase the clutch torque capacity to a level sufficient to withstand the drag torque due to air trapped in the cylinder taking the first compression stroke. The amount of this torque depends on the initial engine starting position since the amount of compressed air will depend on how close that cylinder is to TDC when the engine starting event is started. This therefore complicates the determination of the minimum clutch capacity. An exemplary calibration can examine a machine for several crankshaft starting positions. According to a In the exemplary embodiment, calibrated data from two engine revolutions at 45 degree crank angle intervals can be used to estimate effects of engine starting position. Other intervals or other methods of determining the effects of engine starting position can be used. Differences in clutch torque capacity and engine speed can be used to predict engine operation based on a variable engine starting position. The driveline disturbance can be roughly the same if there is sufficient reserve engine torque to compensate for the clutch load while the vehicle is propelled and can be measured by the change in engine speed in the graph above. Additionally or alternatively, a method is disclosed for moving some or all of the valves of the machine to an open position during the cranking stage or during stage A or part of stage A in order to reduce the torque required to rotate the machine .

During stage B, the engine _speed can be controlled in a controller by T _{e_cmd} . A slip control, which controls the EDC speed difference, can be achieved by a regulation (PI) of the clutch. T _edc can nevertheless be determined as a sum of T _{edc_ol} and T _{edc_cl} . In one embodiment, T _{edc_ol} can be _limited to a low limit value T _{edc_low} in an exemplary range from 20 to 50 Nm. T _{e_cmd} can then be set immediately as follows. $${\text{T}}_{\text{e\_cmd}}={\text{I.}}_{\text{inertia}}*{\mathrm{\alpha }}_{\text{closely}\text{.profile}}-{\text{T}}_{\text{edc\_low}}$$

The speed profile for the machine may include a target speed close to T _{e_synch} . T _{m_cmd} can be expressed as $${\text{T}}_{\text{m\_cmd}}={\text{T}}_{\text{m\_propel}}+{\text{T}}_{\text{m\_comp}}$$

During stage B, the machine can be started up or can be kept in an _inoperative state based on whether _{Ne_synch is} a high value that requires a rapid acceleration of the machine that can be supported by the operation of the machine, and a desire to prevent engine speed overshoot that can result from operation of the engine.

$${\text{T}}_{\text{edc\_ol}}={\text{I}}_{\text{inertia}}*{\mathrm{\alpha }}_{\text{eng}\text{.profile}}-{\text{T}}_{\text{e\_cmd}}$$

$${\text{T}}_{\text{edc\_cl}}={\text{T}}_{\text{PID}}$$

$${\text{T}}_{\text{m\_cmd}}={\text{T}}_{\text{m\_propel}}+{\text{T}}_{\text{m\_comp}}$$

During stage C, T _{e_cmd} can be _decreased to any low level or zero as the torque from the motor is used to get the machine to operate synchronously with the motor. The EDC speed difference can be controlled in a regulation (eg PID regulation) by T _edc . $${\text{T}}_{\text{edc}}={\text{T}}_{\text{edc\_ol}}+{\text{T}}_{\text{edc\_cl}}$$

$${\text{T}}_{\text{edc\_ol}}={\text{I.}}_{\text{inertia}}*{\mathrm{\alpha }}_{\text{closely}\text{.profile}}-{\text{T}}_{\text{e\_cmd}}$$

$${\text{T}}_{\text{edc\_cl}}={\text{T}}_{\text{PID}}$$

$${\text{T}}_{\text{m\_cmd}}={\text{T}}_{\text{m\_propel}}+{\text{T}}_{\text{m\_comp}}$$

Similar to Equation 1, Equation 9 may additionally include a friction torque term. Operation as disclosed in stage C can prevent overshoot beyond the engine speed that may result from transient operation of the engine.

During stage D, the engine speed has been synchronized with the engine speed and the input speed and the EDC speed difference is essentially zero. The EDC can then be fully indented. T _{e_cmd} can be increased to a target level on the basis of the target operation of the drive train, for example on the basis of an output _{torque request} T _{O_REQ} . T _{m_cmd} can be _modulated to a desired level based on a desired operation of the drive train and available torque from the machine.

4th graphically illustrates an exemplary machine start-up on the fly, including associated speeds and torques, including the machine speed, which exceeds the target Engine activation speed profile shoots out. In a top portion of the figure, a horizontal axis illustrates a time period in seconds, and a vertical axis illustrates a rotational speed in revolutions per minute. There are an input speed 302 and an engine speed 304 illustrated. In a central portion of the figure, a horizontal axis corresponds to the same time period as illustrated in the upper portion, and a vertical axis illustrates clutch engagement. A transmission clutch can be used between the engine and a transmission input shaft or within the transmission to dampen or limit torque pulses transmitted through the transmission to the transmission output shaft. According to an exemplary method, a torque capacity of the transmission clutch may be decreased such that torque pulses higher than the torque capacity cause the transmission clutch to slip, thereby dampening the pulse from the torque transmitted through the transmission, or an effect of the engine on the fly the output torque is dampened. It's the gear clutch 306 and the EDC 308 Fig. 13 illustrating a torque capacity created in each of the clutches. In a lower portion of the figure, a horizontal axis corresponds to the same time period as illustrated in the upper portion, and a vertical axis illustrates torque. They are output torques 310 , Engine torque 312 and machine torque 314 illustrated. The input speed 302 accelerates at a constant rate from zero. Gear coupling 306 is initially set and held in an engaged state. For this example, output torque will be 310 fixed to a value and held. In the period that starts when the input speed 302 starts to accelerate, becomes engine torque 312 set to a value to output torque 310 to create. For a period after receipt 302 starts to accelerate, the machine speed remains 304 at zero and the EDC 308 remains in a disengaged state. At the time 320 Stage A of a flying machine start is initiated. EDC 308 transitions to a slip condition, with engine torque 312 can be used to deliver torque to the machine while the machine is rotating 304 and the input speed 302 different values remain. At the time 320 catches the machine speed 304 to accelerate, and engine torque 312 increases to deliver torque to the machine while the output torque 310 is maintained. At the time 330 reaches the machine speed 304 an engine ignition speed 316 , and stage B of the flying machine start can be initiated. At the time 330 the engine can be ignited and put into operation, an engine torque being provided and the engine speed 304 is accelerated based on an engine speed _{profile selected} to achieve _{Ne_synch} . EDC 308 can be reduced to a minimum level, and engine torque 312 returns to a level that represents the output torque 310 without providing any torque to the machine. EDC 308 or the clamping pressure may be reduced to a minimum non-zero value during stage B to reduce or eliminate torque transfer between the machine and the motor while the machine is accelerating under its own power while the clutch is in an un-scavenged condition remains, so that a control of the hydraulic pressure to the clutch can quickly return the clutch to a partially or fully engaged state following stage B. 4th illustrates the engine speed 304 that is on the profile of the input speed 302 shoots out. Furthermore, stage C in this embodiment of the on-the-fly engine start is omitted, and the engine is used to measure the engine speed 304 set according to N _{e_synch} . At the time 340 stage D of the on-the-fly machine start is initiated, N _{e_synch} is reached, and the EDC 308 can be fully indented.

5 Figure 11 graphically illustrates control of clutch pressure based on a clutch pressure command. One embodiment of a pressure regulation module 180 closed loop uses an EDC print command 124 , an actual EDC print 128 and a pressure differential value 126 to control the clutch pressure 366 to control. The pressure sensor shown 362 can be replaced by a pressure estimate. The method illustrated is an exemplary method of accomplishing pressure control, however a number of methods are known in the art. In one embodiment, a variable force solenoid valve (VFS) uses flow controlled valves to provide pressure control. In another embodiment, a duty cycle PWM command can vary voltage rather than current to provide pressure control. An open loop pressure controller module 350 monitors the EDC print command 124 and detects a pressure control solenoid current. Summation module 230 compares the EDC print command with the actual EDC pressure 128 to get a pressure differential value 126 to build. The open loop pressure controller module 350 For example, can use a PI curve to determine pressure control solenoid current. The closed loop pressure controller module 356 monitors a pressure differential value 126 and determines a pressure regulating solenoid valve current. The pressure control solenoid valve flow and the pressure regulation solenoid valve flow are made by summing module 354 sums to form a pressure control solenoid valve flow command. The electricity controller 358 monitors the pressure control solenoid current command and outputs pressure control solenoid current. A PI curve adaptation module 352 monitors the pressure control solenoid valve flow command and the actual EDC pressure 128 and determines a PI curve adaptation for use by the open loop pressure controller module 350 . A pressure control solenoid valve 360 is actuated by the pressure control solenoid valve flow and generates clutch pressure 366 . The clutch pressure 366 is by pressure sensor 362 that outputs the feedback terms that are generated by the modules 356 and 352 to be used. 5 Fig. 10 illustrates an exemplary method of accomplishing pressure control, however a number of methods are known in the art and the disclosure is not intended to be limited to the exemplary embodiments set forth herein.

Methods disclosed herein take advantage of precise control of clutch torques through control of clutch pressures. Like it in conjunction with 5 is disclosed, regulation and control can be used to improve the accuracy of the clutch control. 6th Fig. 10 illustrates an exemplary EDC pressure-to-torque feedforward compensation to account for an occurring difference between the predicted clutch torque and the actual clutch torque at lower clutch pressures due to non-linearity in the clutch pressure-to-torque relationship. A horizontal axis illustrates clutch pressure in kPa delivered to the EDC. A vertical axis illustrates the torque capacity of the EDC in Newton meters. The baseline graph 386 is the conversion of the original clutch pressure into clutch torque based on linear behavior in the clutch. The compensated graph 387 , 388 , 389 and 390 show a conversion of clutch pressure to clutch torque with contained feedforward compensation terms. According to one embodiment, Graph 390 is selected as an optimal EDC pressure-to-torque feed forward compensation selection. According to one embodiment, feed forward compensation terms can be used in a pressure-torque compensation model 205 can be used to take into account non-linear behavior in the coupling.

Disclosed methods include filling an EDC according to an engine speed profile. However, engaging a previously disengaged clutch not only requires compressing the elements of the clutch, but also requires filling the piston associated with the clutch. A method is known for initiating a process of engaging a clutch by using a calibrated fill pulse at a high pressure to begin clutch engagement and reduce any time lag associated with filling the piston. The use of a fill pulse enables a method that relies on minimal torque control of the clutch. To limit the bandwidth requirements of hydraulic actuation, a step command may be issued for the initial clutch torque command after clutch fill. Using this method, the clutch can transmit a relatively constant torque, which reduces a discrepancy between the commanded clutch torque and the estimated clutch torque, which provides better compensation for the EDC torque by the engine. While the EDC is slipping, no fluctuations in the machine torque are transmitted through the clutch to the final drive and only affect the acceleration of the machine. According to one embodiment the hydraulically operated low bandwidth clutch can be used as the coarse actuator, e.g. torque capacity is used to control a constant torque transfer rate, and the much higher bandwidth motor can then be used as the fine actuator in a coarse-fine control configuration.

The motor can be controlled to control torque based on providing output torque to the driveline and torque to aid an engine on-the-fly, as disclosed. However, the control system may not include perfect determinations and control delay times, resulting in some fluctuations in the engine torque that is transmitted to the driveline. These fluctuations in engine torque can be further reduced using modulated pressure on a transmission output clutch. 7th Illustrated an exemplary powertrain that includes a transmission output clutch. The design 400 includes machine 10 , Engine 20th , Energy storage device 30th , Transmission device 40 and coupling device 54 . In addition, there is a transmission input clutch 60 illustrated. When the transmission input clutch 60 is fully engaged, torque may be from or through the engine 20th is transmitted through the transmission input clutch 60 can be transmitted up to a torque capacity for the clutch. However, if the transmission input clutch 60 is operated at any reduced pressure resulting in a lower torque capacity for the clutch, then the clutch will begin to slip at any torque higher than the lower torque capacity. As a result, torque generated by the engine 20th through the transmission input clutch 60 higher than the lower torque capacity is transmitted, not to the transmission 40 or the final drive 56 transfer. The transmission input clutch 60 is as one of the transmission 40 separate facility shown. In another Embodiment can be the transmission input clutch 60 part of the transmission 40 or can be an equivalent coupling device within the transmission 40 his.

7th Figure 3 illustrates an exemplary embodiment of a powertrain that includes a transmission output clutch. However, other configurations of transmissions that include a transmission output clutch are known. 8th Figure 3 illustrates an exemplary powertrain that includes a transmission output clutch used within a transmission. The design 450 includes shaft 452 that is connected to a crankshaft of a machine, EDC 454 , Transmission 458 and output shaft 480 . transmission 458 includes transmission input shaft 453 , Engine 456 , Planetary gear set 460 and clutch 470 that with crowd 472 connected is. The planetary gear set includes a sun gear 468 , the one with the transmission input shaft 453 and engine 456 connected, planetary gear 464 that with output shaft 480 connected, and ring gear 462 that with clutch 470 connected is. engine 456 can the sun gear 456 and the input shaft 453 Apply torque directly. Torque applied to the input shaft 453 can be applied to the shaft 452 and the connected machine by EDC 454 be transmitted. Torque on sun gear 468 is applied, acts on the planet gear 464 . Depending on the condition of the clutch 470 can torque that on planet gear 464 acts on output shaft 480 can be transmitted as output torque, or can by rotating the ring gear 462 be dissipated. When the clutch 470 is fully engaged, torque is transferred to the output shaft based on the torque capacity of the clutch. However, if the pressure on the clutch 470 is reduced, the corresponding lower torque capacity of the clutch 470 used to transmit torque to the output shaft 480 in the same way as the transmission input clutch 60 in development 400 is used. By modulating the pressure on the clutch 470 peaks in the torque above the torque capacity of the clutch are filtered out by the clutch slipping. In this way, the modulation pressure on a transmission output clutch can improve drivability.

9 graphically illustrates an exemplary engine on-the-fly including modulation pressure on a transmission output clutch. In an upper portion of the figure, a horizontal axis illustrates a time period in seconds and a vertical axis illustrates a shaft speed in revolutions per minute. There are an input speed 502 and an engine speed 504 illustrated. In a central portion of the figure, a horizontal axis corresponds to the same time period as illustrated in the upper portion, and a vertical axis illustrates clutch engagement. It is the transmission output clutch 506 and the EDC 508 illustrated. In a lower portion of the figure, a horizontal axis corresponds to the same time period as illustrated in the upper portion, and a vertical axis illustrates torque. They are output torques 510 , Engine torque 512 and machine torque 514 illustrated. The input speed 502 accelerates at a constant rate from zero. The transmission output clutch 506 is initially set to and is initially held in a fully engaged condition. Output torque 510 is fixed to a value and held. In a period that begins when the input speed 502 starts to accelerate, becomes engine torque 512 set to a value to output torque 510 to create. In addition, the torque capacity becomes the transmission output clutch 506 is reduced to any value at or above the reaction torque required for the current output torque until the EDC clutch is finally fully engaged. It is an exemplary required counteractive torque value 518 illustrated. By reducing the pressure on the transmission output clutch 506 the torque transmission to the output shaft can be limited, whereby the output is protected against torque fluctuations during the flying machine start. For a period after receipt 502 starts to accelerate, the machine speed remains 504 at zero and the EDC 508 remains in a disengaged state. At the time 520 Stage A of a flying machine start is initiated. EDC 508 transitions to a slip condition, with engine torque 512 can be used to deliver torque to the machine while the machine is rotating 504 and the input speed 502 different values remain. At the time 520 catches the machine speed 504 to accelerate, and engine torque 512 increases to deliver torque to the machine while the output torque 510 is maintained. At the time 530 reaches the machine speed 504 an engine ignition speed 516 , and stage B of the flying machine start can be initiated. At the time 530 the engine can be ignited and put into operation, providing an engine torque and the engine speed 504 is accelerated based on an engine speed _{profile selected} to achieve _{Ne_synch} . EDC 508 can be reduced to a minimum level, and engine torque 512 returns to a level that represents the output torque 510 without providing any torque to the machine. At the time 535 Stage C of the flying machine start is initiated. EDC 508 is increased and engine torque in a negative direction is used to increase the engine speed 504 based on N _{e_synch} adjust. At the time 540 stage D of the on-the-fly machine start is initiated, N _{e_synch} is reached, and the EDC 508 can be fully indented.

10 FIG. 11 graphically illustrates an exemplary engine on-the-fly that includes a combustion assist method using a lower engine ignition speed in accordance with the present disclosure. In an upper portion of the figure, a horizontal axis illustrates a time period in seconds and a vertical axis illustrates a shaft speed in revolutions per minute. There are an input speed 602 and an engine speed 604 illustrated. In a central portion of the figure, a horizontal axis corresponds to the same time period as illustrated in the upper portion, and a vertical axis illustrates clutch engagement. It is the transmission output clutch 606 and the EDC 608 illustrated. In a lower portion of the figure, a horizontal axis corresponds to the same time period as illustrated in the upper portion, and a vertical axis illustrates torque. They are output torques 610 , Engine torque 612 and machine torque 614 illustrated. The input speed 602 accelerates at a constant rate from zero. The transmission output clutch 606 is initially set and held in a fully engaged condition. Output torque 610 is set to a value and held. In a period that begins when the input speed 602 starts to accelerate, becomes engine torque 612 set to a value to output torque 610 to create. For a period after receipt 602 starts to accelerate, the machine speed remains 604 at zero and the EDC 608 remains in a disengaged state. At the time 620 Stage A of a flying machine start is initiated. EDC 608 transitions to a slip condition, with engine torque 612 can be used to deliver torque to the machine while the machine is rotating 604 and the input speed 602 different values remain. At the time 620 catches the machine speed 604 to accelerate, and engine torque 612 increases to deliver torque to the machine while the output torque 610 is maintained. It is a normal engine ignition speed 616 at which a machine can normally be started, as in the method of 9 is shown. However, as is known in the art, an engine can be fired through a range of speeds. A minimum engine ignition speed 617 can be determined for a machine supplied with torque from a motor on which the machine can be started. By using the minimum engine ignition speed 617 For example, torque can be delivered from the engine to an earlier point in the engine on the fly, thereby allowing the engine to accelerate more aggressively. At the time 630 in 10 reaches the machine speed 604 a minimum engine ignition speed 617 , and stage B of the flying machine start can be initiated. At the time 630 the engine can be ignited and put into operation, providing an engine torque and the engine speed 604 is accelerated based on an engine speed _{profile selected} to achieve _{Ne_synch} . EDC 608 can be reduced to a minimum level, and engine torque 612 returns to a level that represents the output torque 610 without providing any torque to the machine. At the time 635 Stage C of the flying machine start is initiated. EDC 608 is increased and engine torque in a negative direction is used to increase the engine speed 604 set based on N _{e_synch} . At the time 640 stage D of the on-the-fly machine start is initiated, N _{e_synch} is reached, and the EDC 608 can be fully indented. By firing the engine at the lower firing speed, a speed below the normal engine firing speed, torque from the engine can be used earlier in the process and the amount of engine torque that must be used can be reduced. Methods known in the art can be used to determine both a normal engine ignition speed and a lower engine ignition speed for a particular engine and drive train configuration.

11 Fig. 10 graphically illustrates an example engine flying start that includes the use of torque from the engine to achieve a synchronization speed and engine 62 used to engine 20th to assist with the flying machine start. In an upper portion of the figure, a horizontal axis illustrates a time period in seconds and a vertical axis illustrates a shaft speed in revolutions per minute. There are an input speed 702 and an engine speed 704 illustrated. In a central portion of the figure, a horizontal axis corresponds to the same time period as illustrated in the upper portion, and a vertical axis illustrates clutch engagement. It is the transmission output clutch 706 and the EDC 708 illustrated. In a lower portion of the figure, a horizontal axis corresponds to the same time period as illustrated in the upper portion, and a vertical axis illustrates torque. They are output torques 710 , Torque 712 for engine 20th , Torque 718 for engine 62 and machine torque 714 illustrated. The input speed 702 accelerates at a constant rate from zero. The transmission output clutch 706 is initially set and held in a fully engaged condition. Output torque 710 is set to a value and held. In a period that begins when the input speed 702 starts to accelerate, becomes engine torque 712 set to a value to output torque 710 to create. For a period after receipt 702 starts to accelerate, the machine speed remains 704 at zero and the EDC 708 remains in a disengaged state. At the time 720 Stage A of a flying machine start is initiated. EDC 708 transitions to a slip condition, with engine torque 712 can be used to deliver torque to the machine while the machine is rotating 704 and the input speed 702 different values remain. At the time 720 catches the machine speed 704 to accelerate, and engine torques 712 and 718 increase to deliver torque to the machine while the output torque 710 is maintained. Torque 718 is controlled to get extra torque from the engine 62 to deliver, helping to accelerate the machine. Torque 718 can be controlled based on the calibrated behavior of the powertrain or other inputs. At the time 730 reaches the machine speed 704 an engine ignition speed 716 , and stage B of the flying machine start can be initiated. At the time 730 the engine can be ignited and put into operation, providing an engine torque and the engine speed 704 is accelerated based on an engine speed _{profile selected} to achieve _{Ne_synch} . EDC 708 can be reduced to a minimum level, engine torque 718 can be reduced to zero and engine torque 712 returns to a level that represents the output torque 710 without providing any torque to the machine. In 9 will be at time 535 Stage C of the flying machine start initiated. In 11 Illustrated is a method where stage C is omitted from the engine on the fly and engine torque is instead 714 is used to achieve _{Ne_synch} over an extended level B. As soon as _{ne_synch} at the time 740 is reached, stage D of the flying machine start is initiated and the EDC 708 can be fully indented.

12th Figure 11 illustrates an exemplary process for performing an engine on-the-fly. Table 1 is provided as a key, with the blocks marked with numbers and the corresponding functions being carried out as follows. Table 1 BLOCK BLOCK CONTENTS 802 begin 804 Monitor command to operate a flying machine start 806 _Monitor or _Determine N _{e_synch} 808 Operate level A. 810 Operate level B. 812 Operate level C 814 Operate level D. 816 The End

process 800 starts at block 802 . At block 804 a command to operate a flying machine start is monitored. At block 806 N _{e_synch is} monitored or determined, for example on the basis of an input _{speed profile} . In blocks 808 to 814 a flying engine start is carried out in stages A to D. At block 816 the process ends. They are modifications to the process 800 possible, taking for example block 806 is carried out iteratively through a flying machine start, so that N _{e_synch is updated} on the basis of the actual acceleration of the machine and the actual acceleration or actual speed of the input shaft and the motor. A number of example processes for performing an engine on-the-fly start are contemplated, and the disclosure is not limited to the particular example embodiments set forth herein.

Claims (6)

A method for controlling a flying machine start in a drive train (5), which comprises an electric motor (20), which provides a propulsive torque on a transmission input shaft (52), an internal combustion engine (10) and an engine separation clutch (54) which selectively transmits torque between the The machine (10) and the engine (20), the method comprising: a target input speed is monitored; determining a synchronization speed based on the desired input speed; monitoring an output torque request; a propulsion torque is determined on the transmission input shaft (52) on the basis of the output torque request; a compensation torque to be provided at the engine separation clutch (54) for the on-the-fly engine start is determined on the basis of an engine activation speed profile which is determined on the basis of the synchronization speed; controlling the engine (20) to provide an engine torque based on a sum of the propulsion torque and the compensation torque; wherein determining the engine activation speed profile comprises: during a first stage, the compensation torque accelerates the engine (10) from a stopped condition to an engine ignition speed; during a second stage the engine provides torque to accelerate the engine (10); during a third stage following the second stage, only the compensation torque controls the machine (10) to the synchronization speed, the machine torque decreasing again to zero during the third stage; and the machine disconnect clutch is locked during a fourth stage. Procedure according to Claim 1 wherein determining the compensation torque comprises determining a clutch control term and a clutch control term; and wherein determining the engine activation speed profile further comprises during the second stage limiting an engine torque command to be less than the clutch control term. Procedure according to Claim 1 wherein determining the engine activation speed profile further comprises reducing a torque capacity of the engine disconnect clutch to a minimum non-zero value during the second stage. Procedure according to Claim 1 wherein controlling the motor (20) is based on a sum of the propulsion torque, the compensation torque, and an active driveline damping control torque. Procedure according to Claim 1 wherein determining the compensation torque comprises: determining a torque required to rotate the machine (10); and the compensation torque is determined on the basis of the torque required to rotate the machine (10). A system for controlling a flying machine start in a drive train, which comprises an electric motor (20) which provides a propulsion torque on a transmission input shaft (52) of a transmission (40), an internal combustion engine (10) and an engine separation clutch (54) which selectively transmits torque between the machine (10) and the engine (20), the system comprising: the engine (20); and a control module for carrying out the method according to Claim 1 is set up.

Images