DE102015103710B4 - Device for learning a torque loss of an internal combustion engine - Google Patents

Abstract

An engine loss torque learning device that learns a loss torque of an engine (5), the engine loss torque learning device being usable for a vehicle (3) having an idling reduction device (61, S110 to S160) that automatically stops the engine when a predetermined automatic stop condition is satisfied, and then automatically starts the engine when a predetermined automatic start condition is satisfied, the engine loss torque learning device comprising:indicated torque storage means (62a) for storing an indicated torque of the engine during cranking of the engine; torque detecting means (61, S250, S260) for detecting a crankshaft generated torque generated by a crankshaft of the engine during starting of the engine; andlost torque calculating means (61, S270 to S290) for calculating a difference between the indicated torque stored in said indicated torque storing means and the torque generated at the crankshaft detected by said torque detecting means as the lost torque of the engine to calculate.

Description

TECHNICAL AREA

The present invention relates to a device that learns the loss torque of an internal combustion engine.

BACKGROUND OF THE INVENTION

The lost torque (torque loss) of an internal combustion engine must be taken into account in order to control the output torque (torque generated by the crankshaft) of the internal combustion engine. The lost torque is generated by a pumping loss (an intake and exhaust loss) or a friction loss of the engine. The torque loss depends on various factors of an operating state of the machine. For example, the torque loss changes depending on a coolant temperature, an individual difference or manufacturing tolerances, and age-related deterioration. Accordingly, the loss torque needs to be learned in order to improve torque control accuracy of a machine. The JP-2007-278 293A FIG. 12 shows an engine control device that learns the lost torque when the engine is in the idling state.

Recently, the idle reduction control (automatic stop-start control) function is becoming common in vehicles, which automatically stops the engine when a predetermined automatic stop condition is satisfied and then automatically starts the engine when a predetermined automatic start condition is satisfied.

The one considered closest DE 10 2008 000 384 A1 discloses an engine lost torque learning device that learns a lost torque of an engine, the engine lost torque learning device being usable for a vehicle having an idle reduction device that automatically stops the engine when a predetermined automatic stop condition is met and then automatically starting the engine when a predetermined automatic start condition is met, the engine lost torque learning device including an indicated torque storage device to store an indicated torque of the engine.

In the prior art, an engine must be maintained in an operating state (idling state) until a torque loss learning process is completed. Accordingly, automatic stopping of the engine by idle reduction control must be prevented in some cases, thereby deteriorating fuel economy.

SHORT EXPLANATION

It is an object of the invention to provide an engine torque loss learning device which does not affect an idle reduction control.

According to one aspect of the present invention, the engine loss torque learning device is used for a vehicle having an idle reduction control unit that automatically stops the engine when a predetermined automatic stop condition is met and then automatically starts the engine when a predetermined automatic start condition is met.

The engine loss torque learning device includes indicated torque storing means, torque detecting means, and lost torque calculating means.

The indicated torque storage means stores an indicated torque of the engine during the start of the engine. The torque detector detects crankshaft-generated torque generated by a crankshaft of the engine during starting of the engine. The lost torque calculating means calculates a difference between the indicated torque stored in the indicated torque storage device and the torque generated at the crankshaft detected by the torque detecting means as the lost torque of the engine.

In this machine loss torque learning device, a loss torque calculated by the loss torque calculation means can be stored in a memory as a learned value of a loss torque, or can be used to control an engine. Because processing for learning a lost torque is performed during starting of the engine, the automatic stop of the engine by idle reduction control does not have to be prevented. Accordingly, the execution of the idle reduction control is not affected. In addition, since a loss torque can be learned every time the engine is restarted after being auto-recovered by the idle reduction control, a sufficient learning frequency can be secured table is stopped while the vehicle is in use.

character list

• 1 ist ein Schaubild, das den Aufbau einer elektronischen Steuereinheit (ECU) nach einer ersten Ausführungsform zeigt;
• 2 ist ein Schaubild, das eine Drossel zeigt;
• 3 ist ein Ablaufplan, der eine Verarbeitung einer Leerlaufverringerungssteuerung zeigt;
• 4 ist ein Schaubild, das den Betrieb der elektronischen Steuereinheit zeigt;
• 5 ist ein Ablaufplan, der die Verarbeitung zum Lernen des Drehmomentverlusts nach der ersten Ausführungsform zeigt;
• 6 ist ein Ablaufplan, der eine Verarbeitung zur Beschränkung eines Hochdrehens nach einer zweiten Ausführungsform zeigt; und
• 7 ist ein Ablaufplan, der eine Verarbeitung zum Lernen des Drehmomentverlusts nach der zweiten Ausführungsform zeigt.

The above and other objects, features, and advantages of the present disclosure will become more apparent from the following detailed description in conjunction with the accompanying figures. In the figures:

• 1 12 is a diagram showing the structure of an electronic control unit (ECU) according to a first embodiment;
• 2 Fig. 14 is a diagram showing a reactor;
• 3 Fig. 14 is a flowchart showing processing of idle reduction control;
• 4 Fig. 12 is a diagram showing the operation of the electronic control unit;
• 5 Fig. 14 is a flowchart showing torque loss learning processing according to the first embodiment;
• 6 Fig. 14 is a flowchart showing racing restricting processing according to a second embodiment; and
• 7 14 is a flowchart showing torque loss learning processing according to the second embodiment.

ACCURATE EXPLANATION

An electronic control unit according to the embodiments will be described below. The electronic control unit (hereinafter referred to as the ECU) controls the engine (internal combustion) installed in a vehicle and the auxiliary drives of the engine.

[First embodiment]

As in 1 shown, in a vehicle 3 in which an ECU 1 according to the embodiment is installed, torque (ie, output torque of an engine 5) generated by a crankshaft 7 of the engine 5 is transmitted to four wheels 11 to 14 via a transmission (an automatic transmission in the embodiment) 9. Although the vehicle 3 is a four-wheel drive vehicle in this example, the output torque from the engine 5 is transmitted only to the front wheels 11 and 12 out of the wheels 1 to 14 when the vehicle 3 is a front-wheel drive vehicle. When the vehicle 3 is a rear-wheel drive vehicle, the output torque from the engine 5 is transmitted only to the rear wheels 13 and 14 out of the wheels 11-14.

The ECU 1 includes a microcomputer 21 that controls the operation of the ECU 1, an input circuit 23 that inputs a signal from the outside to the inside of the ECU 1, and an output circuit 25 that outputs a signal to the outside of the ECU 1.

The input circuit 23 inputs various signals required to control the engine 5 into the microcomputer 21 . These signals include a crankshaft angle signal from a crankshaft angle sensor 31 which detects a crankshaft angle which is the rotation angle of the crankshaft 7, an engine speed, a cylinder determination signal from a cam angle sensor 32, a vehicle speed signal from a vehicle speed sensor 33 which detects the vehicle speed (the running speed of the vehicle 3), an accelerator pedal signal from an accelerator pedal sensor 36 which detects the amount of operation of an accelerator pedal 35 by the driver of the vehicle 3, a brake signal from a brake sensor 38 that detects the driver's depression of a brake pedal 37, a start signal by the user from a start switch 39 that is operated when the driver wants to start the engine 5 of his own accord, a signal from a throttle opening sensor 42 that detects the opening (hereinafter also referred to as throttle opening) of a throttle 41 (see 2 ) of the machine 5 detected, and the like.

The output circuit 25 outputs a drive current to cause an injector 43 to perform fuel injection in response to a control signal from the microcomputer 21, outputs an ignition signal to cause a spark plug 44 to perform ignition, outputs a drive current to a starter 45 that cranks and starts the engine 5, outputs a drive current to a throttle motor 46 that adjusts the opening of the throttle 41, or outputs an exciting current to adjust the power generation capacity (the amount of electricity generated) of an alternator 47 driven by the engine 5.

Although the injection 43 and the ignition 44 are provided for each of the cylinders of the engine 5 in the embodiment, in FIG 1 only one injector 43 and ignition 44 pair shown. As in 2 As shown, in an intake manifold 51 of the engine 5, the throttle 41 is provided upstream of a surge tank 52, and the opening is adjusted by the throttle motor 46. That is, the throttle 41 and the throttle motor 46 form what is called an electronic throttle 53 . In 2 reference numeral 54 designates a piston which performs a reciprocating motion in a cylinder 55 of the engine 5 Numeral 55 denotes an intake valve, and numeral 57 denotes an exhaust valve.

Related back to 1 the microcomputer 21 comprises a CPU 61 which executes a program, a ROM 62 which stores a program which is executed by the CPU 61, data fetched during execution of a program and the like, a RAM 63 which stores calculation results of the CPU 61 and the like, a non-volatile memory (such as a flash memory or an EEPROM) 64 in which stored data can be rewritten, an analog-to-digital converter (ADC ) 65, and an input/output interface (I/O) 66. An indicated torque storage unit 62a, which is a part of the storage area of the ROM 62, stores indicated torques of the engine 5.

Next, the processing performed by the CPU 61 of the microcomputer 21 will be described. The processing performed by the CPU 61 is achieved by a program in the ROM 62. FIG. The microcomputer 21 is started by a certain supply voltage (e.g. 5V) supplied from a power supply circuit (not shown) when the vehicle enters an ignition-on state and the ECU 1 is supplied with a battery voltage (the voltage of the in-vehicle battery) as an operating power supply. The ignition-on state is a state in which the battery voltage is supplied to the power line of the ignition system in the vehicle. For example, the vehicle enters the ignition-on state when the vehicle's ignition switch is turned on.

The CPU 61 performs injection control processing to control fuel injection from the injector 43, ignition control processing to control ignition by the igniter 44, and throttle control processing to control the throttle opening to make the engine 5 run.

In addition, in response to the starting operation (the processing for turning on the start switch 39 in the embodiment) by the driver, the CPU 61 performs user start processing for starting the engine 5, idle reduction control processing to achieve the function of idle reduction control that automatically stops and automatically starts the engine 5, torque control processing for the engine 5, power generation control processing for the alternator 47, and torque loss learning processing to learn the loss torque of the engine 5.

<User launch or user launch processing>

When a user start signal inputted from the start switch 39 after starting is detected, the CPU 61 performs user start processing.

In the user start processing, the CPU 61 first actuates the starter 45. Then the starter 45 cranks the engine 5, the CPU 61 controls the throttle opening to a predetermined opening for engine run-up through throttle control processing, and performs fuel injection and ignition of the engine 5 through injection control processing and ignition control processing.

When the CPU 61 determines, based on an engine speed calculated from the crank angle signal, that the engine 5 has reached a complete explosion state (a state in which cranking is completed and the engine 5 is started), the CPU 61 stops the operation of the starter 45. User starting means starting the engine 5 in response to a driver starting operation.

<idle reduction control processing>

The CPU 61 executes idle reduction control processing according to 3 for example at predetermined time intervals.

As in 3 As shown, the CPU 61 first determines whether the engine 5 is operating based on, for example, the engine speed in S110 after starting execution of the idle reduction control processing. When the engine 5 is working, the CPU 61 goes to S120.

The CPU 61 determines in S120 whether the automatic stop condition is satisfied. The automatic stop condition is met when, for example, all of the following conditions are met: the brake pedal 37 is depressed, the accelerator pedal 35 is not depressed (the amount of depression of the accelerator pedal 35 is 0), and the vehicle speed is equal to or less than a predetermined value (for example, 5 km/h).

When determining that the automatic stop condition is satisfied, the CPU 61 goes to S130 and performs processing to stop the engine 5 automatically. In this processing, for example, fuel injection from the injector 43 is stopped. In addition, the throttle opening can be adjusted to 0, for example.

The CPU 61 stops the engine 5 in S130 explained above, or the CPU goes to S140 and determines whether idle reduction is taking place if it determines in S110 that the engine 5 is not operating (the engine 5 is stopped). The idle reduction corresponds to the state where the engine 5 is automatically stopped by the processing in S130.

If it is determined that idle reduction is in progress, the CPU 61 goes to S150 and determines whether the automatic start condition is satisfied. The automatic start condition is satisfied when, for example, one of the following conditions is satisfied: the brake pedal 37 is released and the accelerator pedal 35 is depressed (the amount of operation of the accelerator pedal 35 is not “0”).

When determining that the automatic start condition is satisfied, the CPU 61 goes to S160 and automatically starts (i.e., restarts) the engine 5. The processing is the same as the user start processing explained above.

Then, the CPU 61 ends the idle reduction control processing.

If it determines in S120 that the automatic stop condition is not satisfied, determines in S140 that the idle reduction is not taking place, or determines in S150 that the automatic start condition is not satisfied, the CPU 61 ends the idle reduction control processing as it is.

If the automatic stop condition is met, for example, at time t0 in 4 by such idle reduction control processing, the engine 5 is automatically stopped as shown at time t1. If the automatic start condition at time t2 in 4 is met, the machine 5 is automatically restarted. The “BRAKE ON TIME PERIOD” in 4 indicates the period in which the brake pedal 37 is depressed. The "IDLE REDUCTION PERIOD" in 4 indicates the period (the automatic stop period) in which the engine 5 is stopped by the idle reduction control.

<Torque Control Processing>

The CPU 61 determines the target output torque (the target torque generated by the crankshaft 7) of the engine 5 based on information about the requests (for example, the amount of depression of the accelerator pedal 35) indicating requests by the driver and driving information such as an engine speed. Then, the CPU 61 sets the fuel injection amount, fuel injection timing, ignition timing, and throttle opening to the control target values of the injection control processing, the ignition control processing, and the throttle control processing to achieve the target output torque.

In addition, the CPU 61 determines the target output torque in consideration of the learned value of the lost torque of the engine 5 (hereinafter also referred to as the lost torque learned value). Since the torque actually generated by the crankshaft 7 is reduced by the lost torque, the CPU 61 determines the resultant target output torque by correctively increasing the target output torque calculated on the basis of the above requested information and the driving information by the lost torque learned value. The lost torque learning value is updated by the lost torque learning processing described below.

<power generation control processing>

The CPU 61 controls an exciting current flowing through the alternator 47 so that the amount of electric power (the amount of generated electricity) generated by the alternator 47 corresponds to a target value. Although the target value of the amount of generated electricity is determined based on, for example, the electric power balance of the in-vehicle battery, the CPU 61 may obtain the target value through calculation or may obtain the target value from another electronic control unit.

<loss torque learning processing>

During cranking of the engine 5, the CPU 61 acquires the crankshaft generated torque, which is the torque generated by the crankshaft 7, by means of an estimate. “During the cranking of the engine 5” (hereinafter also referred to simply as “during the cranking”) corresponds to the period of time from when the engine 5 starts cranking until the engine 5 is started (until the engine 5 is brought into the complete combustion state or is running smoothly and the rotation speed is equal to the idling rotation speed).

Then, the CPU 61 calculates the difference between the indicated torque stored in the indicated torque storage unit 62a of the ROM 62 and the detected crankshaft generated torque as the lost torque of the engine 5 and stores the calculated lost torque, for example, in the non-volatile memory 64 in an updated manner as a lost torque learned value.

The indicated torque is a torque provided to the crankshaft 7 by combustion, and can be calculated by a measuring device in the engine test bench based on the cylinder pressure.

In the embodiment, the indicated torques stored in the indicated torque storage unit 62a are torques measured in advance in the state where the cylinder intake rate is maximum (100%) (i.e., in the state where the maximum amount of air is trapped in the cylinder 55). In addition, the indicated torques stored in the indicated torque storage unit 62a include at least a maximum indicated torque Ni during the cranking of the engine 5.

In addition, during the starting of the engine 5, the engine speed is once increased and then decreased to the idling speed. This type of engine RPM ramp-up is referred to as flare-up.

Engine speed during cranking is affected by torque loss. When the maximum value (the maximum value of the engine speed once increased and then decreased) of the flare during starting is referred to as the peak speed SP at the start time, the peak speed SP at the start time becomes smaller as the loss torque is larger.

Accordingly, the CPU 61 detects the peak speed SP at the start time and calculates the crankshaft generated torque based on the detected peak speed SP at the start time. A calculated crankshaft generated torque Nc is the maximum torque generated by the crankshaft 7 during starting of the engine 5 . Then, the CPU 61 calculates the difference (Ni - Nc) between the maximum indicated torque Ni stored in the indicated torque storage unit 62a and the crankshaft generated torque Nc calculated based on the peak speed SP at the starting time, as the loss torque of the engine 5.

In order to know more precisely the torque generated at the crankshaft during cranking as long as the combustion is unstable and to know the torque generated at the crankshaft in the same state as the indicated torque, which is the object of comparison, the CPU 61 maximizes the cylinder intake rate during the cranking of the engine 5. More specifically, the CPU 61 performs control to open the throttle 41 further while the engine 5 stops. In this example, the throttle 41 is fully opened (throttle opening = 100%; see the period from time t1 to time t2 in 4 ). When the throttle 41 is opened while the engine 5 is stopped, the pressure in the surge tank 52 located downstream of the throttle 41 of the intake manifold 51 is equal to the atmospheric pressure, and the air amount (represented by the dotted ellipse in 2 shown) contained in the cylinder 55 during starting of the engine 5 is the maximum amount of air that can be contained in the cylinder 55. Although the throttle opening that is controlled while the engine 5 stops can be a value other than 100%, a larger value gives better results. In particular, the pressure in the surge tank 52 immediately becomes equal to the atmospheric pressure when the throttle 41 is fully opened, which increases the effects.

During the starting of the engine 5, a torque Ns that the starter 45 generates is added as the torque for rotating the crankshaft 7. FIG. Accordingly, the torque Ns is added to the torque Nc generated at the crankshaft which the CPU 61 calculates. Therefore, the CPU 61 also performs correction processing to correctively increase the loss torque to be calculated by the torque Ns. In the correction processing, for example, the torque Ns can be added to the calculated loss torque after the loss torque is calculated. Alternatively, the torque Ns can be subtracted from the torque Nc generated at the crankshaft, which is used to calculate the torque loss, before the torque loss is calculated. In both methods the result is the same.

Based on the above description, the lost torque learning processing performed by the CPU 61 will be described with reference to FIG 5 described. The CPU 61 performs the learning processing for the lost torque in 5 for example at certain time intervals.

As in 5 As shown, when starting executing the lost torque learning processing, the CPU 61 first determines in S210 whether the engine 5 is stopping. When determining that the engine 5 is stopping, the CPU 61 performs further opening control of the throttle 41 to fully open it in S220, and then proceeds to S230. The processing in S220 is given priority over the throttle control processing explained above. After the throttle 41 is fully opened in S220, this fully open state is maintained until it is released in S240.

When it is determined in S210 that the engine 5 is not stopping (the engine 5 is in an operating state), the CPU 61 goes to S230.

The CPU 61 determines in S230 whether cranking of the engine 5 has started (i.e., whether cranking by the starter 45 has started). Because the CPU 61 controls the starter 45 in the embodiment, the CPU 61 determines that the cranking of the engine 5 has started when, for example, the power supply to the starter 45 starts. The CPU 61 can also determine whether the cranking of the engine 5 has started based on the crank angle signal.

When it determines in S230 that the cranking of the engine 5 has not started, the lost torque learning processing ends as it is. Accordingly, the result of “NO” is produced in S230 and the lost torque learning processing is completed when the engine 5 is in the operating state or the engine 5 continues to stop.

When it is determined in S230 that the starting of the engine 5 has started, the CPU 61 goes to step S240 to release the control for fully opening the throttle 41. Thereafter, the throttle opening is again controlled by the throttle control processing.

Then, in S250, the CPU 61 detects the peak rotation speed SP at the time of starting by monitoring the engine rotation speed.

Next, in S260, the CPU 61 calculates the torque Nc generated at the crankshaft based on the peak rotation speed SP detected in S250 at the time of start. As described above, the crankshaft generated torque Mc calculated in S250 is the maximum torque generated by the crankshaft 7 during the starting of the engine 5 . In S260, the torque Nc generated at the crankshaft is calculated by, for example, mapping the peak rotation speed SP at the time of start to a calculated expression (an expression for converting rotation speed to torque) set based on the output characteristics of the engine 5. In another example, the CPU 61 may calculate the torque Nc generated by the crankshaft using, for example, a data map for converting a rotating speed into a torque that is set in advance.

The CPU 61 reads the above-mentioned maximum indicated torque Ni from the indicated torque storage unit 62a in S270 and calculates the difference (Ni - Nc) between the maximum indicated torque Ni and the crankshaft generated torque Nc calculated in S260 as a loss torque NL of the engine 5 in S280.

The CPU 61 corrects the lost torque NL calculated in S280 by the torque Ns generated by the starter 45 during cranking in S290. More specifically, the value (NL+Ns) obtained by adding the torque Ns to the lost torque NL calculated in S280 is used as the corrected lost torque NL. The torque Ns may be a predetermined value, for example, or may be calculated based on a measurement value obtained by measuring a drive current flowing through the starter 45 . Alternatively, the torque Ns may be calculated based on a measured value calculated by measuring the battery voltage as a measure of power supply, instead of measuring the driving current flowing through the starter 45.

The CPU 61 stores the lost torque NL calculated in S290 in S300 as a lost torque learning value, for example, in the non-volatile memory 64 in an updating manner, and ends the lost torque learning processing.

The processing in S290 is correction processing for correctively increasing the lost torque NL calculated by the lost torque learning processing by the torque Ns. In this correction processing, however, instead of the correction processing in S290, the CPU 61 may perform processing for decreasing the crankshaft generation torque Nc used in S280 by the torque Ns to calculate the lost torque NL. Such a modification does not change the result.

In the above-described ECU 1, the maximum rotating speed SP is detected during restarting (S250) after the engine 5 is automatically stopped by the idle reduction control when the automatic starting condition is at time t2 in, for example 4 is satisfied and the engine 5 has been automatically restarted by the idle reduction control. Then, the crankshaft generated torque Nc is calculated based on the maximum speed SP at the time of starting (S260), the lost torque NL of the engine 5 is calculated based on the crankshaft generated torque Nc and the maximum indicated torque Ni (S270 to S290), and the lost torque learning value is updated (S300). Although this in 4 not shown, the lost torque NL is similarly calculated not only during the automatic restart of the engine 5 but also during the user's starting, and the lost torque learned value is updated.

In the ECU 1 described above, since the processing for learning a lost torque is performed during the cranking of the engine 5, an automatic stop of the engine 5 does not have to be prevented by idle reduction control.

For example, the dotted waveforms in 4 Consider the case of a conventional device that learns a loss torque while the engine 5 is idling. In the conventional device, even if the automatic stop condition at time t0 in 4 is satisfied. Among the in 4 In periods indicated by dotted arrows, a period TLo is a period in which the processing for learning a lost torque is performed by a conventional device. The period TSo is an idle reduction period in the case where a conventional device is used. The period TSo is shorter than the idle reduction period in the case where the ECU 1 according to the embodiment is used. Thus, fuel economy deteriorates in a conventional device.

On the other hand, the ECU 1 according to the embodiment does not affect execution of idle reduction control and does not deteriorate fuel economy. In addition, since the ECU 1 can learn a loss torque each time the engine 5 is restarted after an automatic stop by idle reduction control while the vehicle 3 is in use, a sufficient learning frequency can be secured.

The torque generated at the crankshaft, which is used to calculate a torque loss, can be sensed by providing a torque sensor, for example. On the other hand, such a torque sensor (a sensor for detecting the torque generated at the crankshaft) need not be provided because the ECU 1 calculates the torque generated at the crankshaft based on the engine speed during cranking.

For example, the indicated torque and the crankshaft generated torque used to calculate the lost torque may be values at the time when a predetermined time has elapsed after the start of cranking of the engine 5 (the start of cranking). On the other hand, the indicated torque and the torque generated at the crankshaft used to calculate the lost torque are the maximum values during cranking. More specifically, the indicated torque used to calculate the torque loss is the maximum indicated torque during cranking, and the torque generated at the crankshaft used to calculate the torque loss is also the maximum torque generated by the crankshaft 7 during cranking. Accordingly, the target for the comparison becomes clearer and the accuracy for calculating the loss torque becomes better.

In addition, the ECU 1 detects the maximum rotation speed at the time of cranking during the cranking time, which is the maximum value of the engine rotation speed (a flare) that increases and then decreases, and calculates the crankshaft generated torque (that is, the maximum value of the torque generated at the crankshaft during cranking) based on the maximum rotation speed at the time of cranking. Accordingly, the maximum value of the torque generated at the crankshaft during cranking can be easily and accurately calculated. For example, the maximum value of the torque generated at the crankshaft during cranking can be calculated based on the manner in which the monitored engine speed increases (the manner in which the engine speed increases), but the processing explained above is simpler than this structure.

The indicated torque used to calculate the lost torque in the ECU 1 is the torque measured in the state where the cylinder intake rate is maximum. The torque generated at the crankshaft, which is used to calculate the loss torque, is also adjusted to the value in the state where the cylinder intake rate is maximum by opening the throttle 41 fully while the engine 5 stops maximizing the cylinder intake rate during cranking. Accordingly, the indicated torque, which is the target for comparison, and the crankshaft generated torque can be values under the same condition, and the crankshaft generated torque during cranking where combustion is unstable can be obtained more accurately. Accordingly, the calculation calculation accuracy of the torque loss can be increased.

In addition, since the ECU 1 adds the torque generated by the starter 45 during cranking to the lost torque to be calculated, the calculation accuracy of the lost torque can be increased.

[Second embodiment]

Next, an ECU according to a second embodiment will be described, and the ECU is given reference numeral 1, which is the same as in the first embodiment. The components and flow that are the same as in the first embodiment are also given the same reference numerals.

Because the throttle 41 is fully opened while the engine 5 stops to maximize the cylinder intake rate during cranking in the ECU 1 according to the first embodiment as described above, the maximum value of the flare during starting may become too large depending on the type of the engine 5.

• <1> Die CPU 61 des Mikrocomputers 21 führt die Beschränkungsverarbeitung für das Hochjagen in 6 während des Anlassens der Maschine 5 durch. Wie in 6 gezeigt beschränkt die CPU 61 in der Verarbeitung zur Beschränkung des Hochjagens das Hochjagen der Maschinendrehzahl während des Anlassens durch Steuern des Lastmoments (des Moments, das auf die Kurbelwelle 7 als eine Last wirkt) der Lichtmaschine 47 auf einen vorab festgelegten Wert Ng (S310). Das Lastmoment der Lichtmaschine 47 kann durch einen Erregerstrom für die Lichtmaschine 47 gesteuert werden.
• <2> Die CPU 61 führt die Verlustmomentlernverarbeitung nach 7 anstelle der Verlustmomentlernverarbeitung in 5 durch. Die Verlustmomentlernverarbeitung in 7 unterscheidet sich von der Verlustmomentlernverarbeitung in 5 dadurch, dass S285 zwischen S280 und S290 hinzugefügt ist.

When the ECU 1 according to the second embodiment is compared with the ECU 1 according to the first embodiment, taking the above into consideration, there are the differences described by <1> and <2> as shown below.

• <1> The CPU 61 of the microcomputer 21 executes the restriction processing for the blow-up in 6 during starting of the engine 5 through. As in 6 As shown, in the racing restriction processing, the CPU 61 restricts the racing of the engine speed during cranking by controlling the load torque (the torque acting on the crankshaft 7 as a load) of the alternator 47 to a predetermined value Ng (S310). The load torque of the alternator 47 can be controlled by an exciting current for the alternator 47 .
• <2> The CPU 61 traces the lost torque learning processing 7 instead of the loss torque learning processing in 5 through. The loss torque learning processing in 7 differs from the loss torque learning processing in 5 by adding S285 between S280 and S290.

As in 7 As shown, the CPU 62 corrects the loss torque NL calculated in S280 by the predetermined value Ng in S285. More specifically, the value (NL - Ng) obtained by subtracting the predetermined value Ng from the lost torque NL calculated in S280 is used as the corrected lost torque NL. Then, in S290, the CPU 61 further corrects the lost torque NL calculated in S285 as described above.

Although the processing in S285 is correction processing to correctively decrease the lost torque NL calculated by the lost torque learning processing by the lost torque (predetermined value Ng) of the alternator 47, instead of S285, processing may be performed to increase the torque Nc generated at the crankshaft used to calculate the lost torque NL in S280 to increase the predetermined value Ng. Such a modification does not change the result. As another modification, the processing in S285 can be performed after S290.

The ECU 1 according to the second embodiment as described above can ensure the good calculation accuracy of the loss torque while restraining excessive flare during cranking.

Embodiments of the invention have been described above, but the invention is not limited to the above embodiments and can be embodied in various forms. In addition, the values explained above are only examples and other values can be used.

For example, in the above embodiments, it is assumed that the transmission 9 of the vehicle 3 is an automatic transmission and the shift range of the transmission 9 is the drive range (D range) when the engine 5 is automatically started by the idle reduction control. Accordingly, the following configuration is desirable in order to obtain a value that does not include a torque loss by the transmission 9 (hereinafter referred to as transmission loss torque) as the loss torque of the engine 5 calculated by the loss torque learning processing during the automatic starting of the engine 5.

This means that the value obtained by subtracting the gearbox torque loss from S290 in 5 and 7 calculated torque loss NL only has to be the torque loss that was finally calculated. The transmission torque loss used for the extraction may be, for example, a constant value obtained experimentally, or the transmission torque loss may be variable depending on the coolant temperature or oil temperature of the engine, the temperature of the ATF (automatic transmission fluid), the temperature of the outside air and the like can be variably set.

The function of one component in the above embodiments may be distributed to a plurality of components, or the functions of a plurality of components may be integrated into one component. At least part of the structure of the above embodiments can be replaced with a known structure having a similar function. Part of the configuration of the above embodiments may be omitted as long as the problem can be solved. Any aspects defined in the appended claims that fall within the scope described in the specification are embodiments of the invention. The invention can be achieved in various forms such as the ECU explained above, a system including the ECU as a component, a program that causes a computer to function as the ECU, a medium in which the program is recorded, and a method for learning the lost torque.

• Eine Vorrichtung zum Lernen des Maschinenverlustmoments wird für ein Fahrzeug verwendet, das eine Leerlaufverringerungssteuervorrichtung aufweist. Die Vorrichtung zum Lernen des Maschinenverlustmoments lernt ein Maschinenverlustmoment.

In summary, the present invention provides the following:

• An engine loss torque learning device is used for a vehicle having an idle reduction control device. The engine-loss torque learning device learns an engine-loss torque.

The engine lost torque learning apparatus includes an indicated torque storage unit for storing an indicated torque of the engine during engine cranking, a torque detection unit (S250, S260) for detecting crankshaft generated torque generated by a crankshaft of the engine during engine cranking, and a lost torque calculation unit (S270 to S290) to calculate, as the engine lost torque, a difference between the indicated torque stored in the indicated torque storage unit is, and to calculate the torque generated at the crankshaft detected by the torque detection unit.

Reference List

7

internal combustion engine

9

transmission

23

input circuit

21

microcomputer

25

output circuit

46

engine

52

surge tank

54

Pistons

62a

Declared torque

64

Non-Volatile Storage

S110

Engine running?

S120

Is condition for automatic stop met?

S130

Stop engine automatically

S140

Does idle reduction progress?

S150

Is the condition for automatic start met?

S160

Start engine automatically

S210

Does the engine stop?

S220

Open throttle fully

S230

Has the engine started?

S240

Release or cancel full throttle opening

S250

Detect peak speed SP at the time of start

S260

Calculate torque Nc generated at the crankshaft based on SP

S270

Read declared torque (max. declared torque) Ni

S280

Calculate torque loss NL (NL = Ni - Nc)

S285

Correct loss torque NL (NL = NL - Ng)

S290

Correct loss torque NL (NL = NL + Ns)

S300

Store loss torque NL

S310

Control alternator load torque to pre-determined value

Claims (7)

An engine loss torque learning device that learns a loss torque of an engine (5), the engine loss torque learning device being usable for a vehicle (3) having an idling reduction device (61, S110 to S160) that automatically stops the engine when a predetermined automatic stop condition is satisfied and then automatically starts the engine when a predetermined automatic start condition is satisfied, the engine lost torque learning device comprising: indicated torque storage means (62a) for storing an indicated torque of the engine during cranking of the engine; torque detecting means (61, S250, S260) for detecting a crankshaft generated torque generated by a crankshaft of the engine during starting of the engine; and lost torque calculating means (61, S270 to S290) for calculating a difference between the indicated torque stored in said indicated torque storing means and the torque generated at the crankshaft detected by said torque detecting means as the lost torque of the engine. Machine loss torque learning device according to claim 1 wherein the torque detecting means detects the torque generated at the crankshaft by calculating the torque generated at the crankshaft based on an engine speed during engine cranking. Machine loss torque learning device according to claim 1 or 2 , wherein the indicated torque is a maximum indicated torque during engine cranking; and the torque generated at the crankshaft detected by the torque detecting means is a maximum torque generated by the crankshaft during starting of the engine. Machine loss torque learning device according to claim 3 , wherein the torque detecting means detects the torque generated at the crankshaft by calculating the torque generated at the crankshaft based on a maximum speed at the time of cranking detected during the cranking of the engine, the maximum speed during the cranking being a maximum value of an engine speed that increases and then decreases. Machine loss torque learning device according to one of Claims 1 until 4 , further comprising: an adjustment device (61, S220) for maximizing a cylinder intake rate during starting of the engine by controlling to further open a throttle (41) of the engine while the engine stops, wherein the indicated torque is measured when the cylinder intake rate is maximum. Machine loss torque learning device according to claim 5 , further comprising: restricting means (61, S310) for restricting an engine speed from racing during engine starting by controlling a load torque of an alternator driven by the engine to a predetermined value, wherein the lost torque calculating means has a function (S285) of correctively decreasing the lost torque to be calculated by the predetermined value. Machine loss torque learning device according to one of Claims 1 until 6 wherein the lost torque calculating means has a function (S290) of correctively increasing the lost torque to be calculated by a torque generated by a starter during the cranking of the engine.

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