JP2003120801A - Power transmission device - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To always calculate an accurate engine output torque in response to a change in an operation parameter with a small amount of data. When a control line pressure of a transmission for shifting an output of an engine E is set by a control valve CV, a reference indicated torque is calculated based on an engine speed Ne and an intake negative pressure PB (block B3). ), A correction coefficient KTQ is calculated based on the difference between the operation parameters of the actual operation state and the reference operation state (block B5),
The reference indicated torque is corrected to calculate the actual indicated torque generated in the actual operation state (block B6), and the friction torque of the engine is calculated based on the engine speed and the load (block B4). The engine torque is calculated by subtracting the friction torque (block B7), and the line pressure is set according to the net torque.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power transmission device configured to transmit a driving force from an engine to wheels via a speed change mechanism, and more specifically, a parameter for controlling an operation of the speed change mechanism (for example, a parameter). , A line pressure, a transmission torque capacity, a shift characteristic, etc.).

[0002]

2. Description of the Related Art A power transmission device having such a speed change mechanism is widely used in automobiles and the like, and the operation control of the speed change mechanism is generally performed using hydraulic oil of a predetermined hydraulic pressure (line pressure). Has become. For example, JP-A-60-25666
Japanese Patent Publication No. 2 discloses a control device that supplies line pressure to a hydraulic cylinder for controlling the pulley width in a belt type continuously variable transmission to control the pressing force of the belt by the pulley.
In this control device, the engine output torque (net torque) is calculated from the engine speed, the intake negative pressure, etc., and the line pressure is set according to the calculated torque.

If the line pressure is set in accordance with the engine output torque in this way, the engagement capacity of the clutch or the like in the transmission mechanism set by using the line pressure transmits the engine output torque to the wheels. It is possible to set the required minimum capacity, and it is possible to improve the fuel efficiency by suppressing the engine energy (hydraulic pump drive energy) used to create the line pressure to the necessary minimum. In addition, when the clutch engagement capacity is set to the minimum value necessary for transmitting the engine output torque in this way, when the engine output or the running load of the vehicle is suddenly changed (for example, a sudden operation of the accelerator pedal). When the vehicle is operated or when the vehicle goes over a curb), the clutch or the like slips to suppress the torque change, and the drivability and the runnability are improved. Further, in the belt type continuously variable transmission, the pressing force of the belt can be minimized to improve the durability of the belt, and the transmission mechanism can be made compact and compact.

However, if the calculation of the engine output torque is inaccurate, the engagement capacity of the clutch or the like must be set on the safe side in consideration of the calculation error, and the line pressure will also be set on the higher side. . From the above, the above-mentioned JP-A-60
In the device disclosed in Japanese Laid-Open Patent Publication No. 2565662, an engine output torque is calculated from an engine speed, a throttle opening or an intake air amount per engine unit rotation and other engine operating parameters, and the calculated engine output torque is handled. Then, the line pressure is set.

[0005]

However, when calculating the engine output torque in this way, the engine output torque generally depends on the engine speed and the engine load (engine intake negative pressure, engine throttle opening, etc.). Correspondingly determined, but operating parameters (e.g. air-fuel ratio,
Since this correspondence changes according to the EGR (exhaust gas recirculation) state, retard amount, etc.), it is necessary to grasp the correspondence between the engine speed and the load for each operating parameter in advance, and the control data There is a problem of enormous volume.
For example, a map indicating engine output with respect to engine speed and engine load is set and stored when the engine is operated with an air-fuel ratio of stoichiometric (theoretical air-fuel ratio) and when the engine is operated with a lean (low air-fuel ratio). It is necessary to calculate the engine output torque by selecting and using a map according to the state of the air-fuel ratio. Since a plurality of maps are set and stored in this way, there is a problem that the capacity of the ROM that constitutes the electric control unit becomes excessively large, leading to an increase in cost. Even when EGR or retard is performed, a plurality of maps are required corresponding to the reflux rate and the retard amount, and there is a similar problem.

Further, these are controlled when the air-fuel ratio is variably controlled as in the direct fuel injection type engine, when the EGR recirculation rate is variably controlled, or when the retard amount is variably controlled. Air-fuel ratio, exhaust gas recirculation rate,
Although it is necessary to use a large number of maps corresponding to the retard amount, it is currently very difficult to use a large number of maps due to the ROM capacity and the like. For this reason, engine output torque is calculated by using a reference map and correcting with a correction coefficient according to the air-fuel ratio or exhaust gas recirculation rate. Actually uses the torque (net torque) output from the engine output shaft, and engine friction torque (torque lost due to piston reciprocation resistance and rotation resistance in the cylinder and supply / exhaust valve due to piston reciprocation) This is a torque that is the sum of torques such as pumping loss that is generated by the air flow passing through, and does not consider the torque that is lost before reaching the output shaft. Therefore, the calculated value of the engine output torque becomes inaccurate. There is.

Here, the calculated value of the engine output torque is
Used to set the line pressure for hydraulic operation control of the transmission,
It is used to set the transmission torque capacity of the clutch that is engaged using such hydraulic pressure. For this reason, if the calculation of the engine output torque is inaccurate, it is necessary to set a large line pressure in consideration of the safety factor and a large transmission capacity, which increases loss torque and reduces fuel consumption. There's a problem. Further, the gear shift control characteristic in the transmission is also set based on the calculated engine output torque, which causes a problem that the setting of the gear shift control characteristic tends to be inaccurate. In particular, when the traveling road surface gradient is calculated from the calculated output torque, traveling resistance, acceleration resistance, and the like, and when performing control to change over the shift map according to the road surface gradient,
If the calculated value of the output torque is inaccurate, the changeover control of the shift map becomes inaccurate, which may cause a problem that the fuel economy is lowered without performing the shift until the engine speed is high.

The present invention has been made in view of these problems.
The amount of data required to calculate the engine output torque is small,
Another object of the present invention is to provide a power transmission device configured such that the engine output torque can always be accurately calculated in response to changes in operating parameters such as the air-fuel ratio, EGR recirculation rate, and retard amount.

[0009]

In order to achieve such an object, the present invention provides a speed change mechanism (for example, a continuously variable transmission CVT in the embodiment) for speed-changing and transmitting a rotational driving force from an engine, and a speed change mechanism. A parameter setting device (for example, the control valve C in the embodiment) that variably sets control parameters for controlling the operation of the mechanism (for example, the line pressure for the speed change mechanism, the transmission torque capacity of the friction engagement element, the speed change characteristic, etc.).
V), the reference indicated torque calculating means for calculating the reference indicated torque of the engine in the reference operating state based on the engine speed and the load (for example, the engine intake negative pressure PB in the embodiment). (For example, block B3 in the embodiment) and the reference indicated torque is corrected based on the difference in the operating parameters between the actual operating state of the engine and the reference operating state to calculate the actual indicated torque generated in the actual operating state. Actually illustrated torque calculation means (for example, blocks B5 and B6 in the embodiment)
And a friction torque calculating means for calculating the friction torque of the engine based on the engine speed and the load (for example, block B4 in the embodiment), and a friction torque calculating means from the actual indicated torque calculated by the actual indicated torque calculating means. And a net torque calculating means (for example, block B7 in the embodiment) that subtracts the friction torque calculated by the above to calculate the net torque of the engine.
The control parameter is set according to the net torque calculated by the net torque calculating means.

The indicated torque is the total torque actually generated by the engine, and is the torque obtained from the fuel supplied to the engine and burned. From the indicated torque, the remainder excluding the torque (friction torque) used for reciprocating the piston in the engine, rotating each shaft, and being used is output to the engine output shaft. Thus, the torque output from the engine output shaft is the net torque, which is used to drive the engine drives (for example, the compressor for the air conditioner, the hydraulic pump, etc.) and the wheels. The relationship between these respective torques is shown in the form of a bar graph in FIG. 7, and the total of the net torque represented by the black-painted portion and the friction torque represented by the gray portion is the indicated torque.

The indicated torque is a total torque generated from the engine by burning the fuel supplied to the engine, and theoretically, it is accurate in operating parameters such as the air-fuel ratio, the exhaust gas recirculation rate at the ERG, and the retard amount. Is a value that changes according to. For example, in the case of FIG. 7, the engine speed Ne = A and the intake negative pressure (engine load) PB
= A, the indicated torque in the stoichiometric state (theoretical air-fuel ratio state) and the indicated torque in the lean state (low air-fuel ratio state) change corresponding to the value of the air-fuel ratio. Similarly, the indicated torque in the EGR operation and the retard operation also changes according to the EGR recirculation rate and the retard amount, and this relationship is at the time of the low load operation in which the engine speed Ne = A and the intake negative pressure PB = B. Is also the same. Therefore, the reference indicated torque when the engine is operated under the reference operating parameters (for example, at the theoretical air-fuel ratio, at a predetermined exhaust gas recirculation rate, and without retard) is set to the engine rotational speed Ne and the intake negative pressure PB ( Alternatively, the throttle opening θTH may be used). If it is set and stored in advance, the actual engine speed Ne and the reference indicated torque at the intake negative pressure PB are read, and then the reference operation parameter is set. Only by correcting the reference indicated torque based on the difference in the actual operating parameters, the actual indicated torque generated from the engine can be accurately calculated under the actual operating parameters.

The present invention uses such a method, and the reference indicated torque in the reference operating state (the operating state under the reference operating parameter) is used as the operating parameter between the actual operating state and the reference operating state. The actual illustrated torque is calculated by making a correction based on the difference, so that the actual engine generated under any operating parameter (that is, even when the operating parameter changes) The torque can be calculated accurately. In this case, since only the reference indicated torque in the reference operation state and the correction coefficient corresponding to the operation parameter are required, the amount of data required for calculating the actual indicated torque may be small, and the storage medium capacity (ROM capacity) is small. Good. In the present invention, the net torque is calculated by subtracting the friction torque of the engine from the thus-calculated actual indicated torque, so that an accurate net torque can be calculated under any operating parameter.

In the present invention, the control parameter is set by the parameter setting device on the basis of the net torque, whereby the engagement capacity of the clutch or the like in the transmission mechanism set by using the control parameter is set to the engine output. It is possible to accurately set the minimum required capacity for transmitting torque to the wheel side, for example, to minimize the engine energy used to create line pressure, transmission torque capacity, etc. It is possible to suppress it and improve fuel efficiency. If the clutch engagement capacity is set to the minimum value required to transmit the engine output torque in this way, the transmission torque will change abruptly when the accelerator pedal is suddenly operated, or when a curb is passed over. Even if the clutch or the like slips, the torque change is suppressed, and the drivability and the traveling property are improved. Further, in the belt type continuously variable transmission, the pressing force of the belt can be minimized to improve the durability of the belt, and the transmission mechanism can be made compact and compact.

If the shift control characteristic of the transmission is also set based on the net torque accurately calculated in this way, the shift control characteristic can be set accurately. In particular, if the running road surface gradient is calculated from the net torque, running resistance, acceleration resistance, etc. calculated in this way, it is possible to set an accurate road surface gradient, and it is possible to carry out shift map control accurately according to the road surface gradient. Is.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a sectional view of a vehicle power transmission device according to an embodiment of the present invention, and FIG. 2 shows a power transmission system configuration of this device. As can be seen from both of these figures, this device includes an engine E, an electric motor generator M disposed on an output shaft Es of the engine E, and a coupling mechanism C on the engine output shaft Es.
It is composed of a continuously variable transmission CVT connected via P.

The engine E is a four-cylinder reciprocating type engine, and pistons are arranged in four cylinder chambers 21 formed in a cylinder block 20, respectively. The engine E performs an intake / exhaust control device 22 for controlling the operation of an intake valve and an exhaust valve for intake / exhaust of each cylinder chamber 21, and a fuel injection control for each cylinder chamber 21 and an ignition control of injected fuel. It has a fuel injection / ignition control device 23. The electric motor generator M can be driven by an on-vehicle battery to assist the engine driving force, and
During deceleration, the wheels can be driven to rotate to generate electric power to charge the battery (energy regeneration). As described above, the power transmission of the present power transmission device has a hybrid type configuration.

The continuously variable transmission CVT includes a metal V-belt mechanism 10 arranged between the input shaft 1 and the counter shaft 2, a forward / reverse switching mechanism 20 arranged on the input shaft 1, and a counter. Starting clutch (main clutch) arranged on the shaft 2
And 5. This continuously variable transmission CVT is used for a vehicle, the input shaft 1 is connected to the engine output shaft Es via a coupling mechanism CP, and the starting clutch 5 is used.
From the differential mechanism 8 is transmitted to the left and right wheels (not shown) via the left and right axle shafts 8a and 8b.

The metal V-belt mechanism 10 includes a drive side movable pulley 11 arranged on the input shaft 1, a driven side movable pulley 16 arranged on the counter shaft 2, and both pulleys 1.
It is composed of a metal V-belt 15 wound around 1 and 16. The drive-side movable pulley 11 has a fixed pulley half body 12 rotatably arranged on the input shaft 1 and a movable pulley half body 13 that is movable relative to the fixed pulley half body 12 in the axial direction. The drive-side cylinder chamber 1 is surrounded by the cylinder wall 12a on the side of the movable pulley half body 13.
4 is formed, and drive side pressure for moving the movable pulley half body 13 in the axial direction is generated by the pulley control hydraulic pressure supplied to the drive side cylinder chamber 14 from the control valve CV via the oil passage 31.

The driven-side movable pulley 16 is composed of a fixed pulley half body 17 fixed to the counter shaft 2 and a movable pulley half body 18 which is axially movable relative to the fixed pulley half body 17. A driven side cylinder chamber 19 is formed on the side of the movable pulley half body 18 by being surrounded by a cylinder wall 17a, and a pulley control is supplied to the driven side cylinder chamber 19 from a control valve CV via an oil passage 32. The hydraulic pressure generates driven side pressure that moves the movable pulley half 18 in the axial direction.

As can be seen from the above structure, the hydraulic pressure (drive and driven side pressure) supplied to both cylinder chambers 14 and 19 is controlled by the control valve CV to provide a side pressure at which the belt 15 does not slip. Further, control is performed to make the drive and driven side pressures different from each other, and the pulley groove widths of both pulleys are changed to change the metal V-belt 1.
Control for changing the winding radius of No. 5 and steplessly changing the gear ratio is performed. In this way, the drive and driven side pressure for performing the gear ratio control are set using the line pressure obtained by adjusting the hydraulic pressure from the hydraulic pump (not shown) driven by the engine E by the regulator valve. Specifically, the side pressure on the high pressure side of the drive and driven side pressures is set using the line pressure.

The forward / reverse switching mechanism 20 is composed of a planetary gear mechanism, and has a sun gear 21 connected to the input shaft 1, a ring gear 22 connected to the fixed pulley half 12, and a carrier which can be fixedly held by a reverse brake 27. 23, and a forward clutch 25 capable of connecting the sun gear 21 and the ring gear 22. In this mechanism 20, when the forward drive clutch 25 is engaged, all the gears 21, 22, 23 rotate integrally with the input shaft 1, and the drive side pulley 11 is driven in the same direction as the input shaft 1 by the drive of the engine E (forward drive). Direction). On the other hand, when the reverse brake 27 is engaged, the carrier 23 is fixedly held, so that the ring gear 22 is driven in the direction opposite to the sun gear 21, and the drive side pulley 11 is opposite to the input shaft 1 by the drive of the engine E. It is driven to rotate in the direction (reverse direction). In addition, these forward clutches 2
5 and the engagement operation of the reverse brake 27 are controlled by the forward / reverse control hydraulic pressure set by using the line pressure in the control valve CV.

The starting clutch 5 is a clutch for controlling the power transmission between the counter shaft 2 and the output side member, that is, the power transmission gears 6a, 6b, 7a, 7b. When the starting clutch 5 is engaged, the power transmission between the two is performed. It will be possible. Therefore, when the starting clutch 5 is engaged, the engine output changed by the metal V-belt mechanism 10 is transmitted to the power transmission gear 6
It is transmitted to the differential mechanism 8 via a, 6b, 7a, 7b, divided by the differential mechanism 8 and transmitted to the left and right wheels via the left and right axle shafts 8a, 8b. When the starting clutch 5 is released, such power transmission cannot be performed and the transmission is in a neutral state.
Such engagement control of the starting clutch 5 is performed by supplying, via the oil passage 33, the clutch control hydraulic pressure set by using the line pressure in the control valve CV.

Continuously variable transmission CVT configured as described above
In the above, the shift control is performed by the drive and driven side pressure supplied from the control valve CV via the oil passages 31 and 32 as described above, and is supplied to the forward clutch 25 and the reverse brake 27 via an oil passage (not shown). Forward / backward switching control is performed by the forward / backward control hydraulic pressure,
The starting clutch engagement control is performed by the clutch control hydraulic pressure supplied via the oil passage 33. The operation of the control valve CV is controlled based on a control signal from the electric control unit ECU.

The power transmission device having the above-described structure is mounted on a vehicle and operated, but the electric motor generator M is used.
Assists the driving force of the engine E and drives the engine E in the range with the best fuel economy to improve the fuel economy when the vehicle is driven. Therefore, the electric motor generator M is operated and controlled based on the control signal from the electric control unit ECU via the control line 36. At the same time, gear change control is performed so as to set a gear ratio that allows the engine E to be operated in a range where fuel consumption is as good as possible. This control is performed by the electric control unit ECU via the control line 35. This is done by the control signal sent to the control valve CV.

Further, in the engine E, some of the four cylinders can be deactivated in a predetermined operation state (for example, a deceleration operation state) to perform a partial cylinder operation. That is, the electric control unit ECU controls the operation of the intake / exhaust control device 22 via the control line 37 and the operation of the fuel injection / ignition control device 23 via the control line 38, thereby controlling the operation of the several cylinder chambers 21. It is possible to perform partial cylinder operation without keeping the intake / exhaust valve in the closed state and performing neither fuel injection nor ignition. As a result, the fuel consumption during deceleration traveling is improved, the engine braking force is reduced, and the deceleration energy is reduced to the electric motor generator M.
Can regenerate efficiently.

In this device, idling stop control is also performed in order to further improve fuel efficiency. The idling stop control is basically a control for stopping the driving of the engine itself when the vehicle is stopped and the engine is in the idling state, since the driving force of the engine is unnecessary. In this device, when the accelerator pedal is released while the vehicle is running to decelerate and stop the vehicle, the fuel injection cut control that is performed when the vehicle is decelerated is continued as it is to perform idling stop control to improve fuel economy. I am trying to improve.

In the power transmission device configured as described above, when the vehicle is traveling, the electric control unit ECU
The control for controlling the operation of the control valve CV to set the line pressure will be described with reference to the block diagram of FIG. First, engine intake negative pressure PB and engine speed N
e is detected (blocks B1 and B2), and the reference indicated torque TQTB corresponding to this is calculated (block B3). This reference indicated torque TQTB is the total torque obtained from the engine in a standard operating parameter, for example, in an operating condition (standard operating condition) under a stoichiometric (theoretical air-fuel ratio) condition with a predetermined EGR recirculation rate and no retard. Is preset in a table corresponding to the intake negative pressure PB and the rotation speed Ne, and the reference indicated torque TQTB corresponding to the detected intake negative pressure PB and the rotation speed Ne is read from this table and calculated. Thereby, for example, the indicated torque in the stoichiometric state in FIG. 7 is calculated as the reference indicated torque TQTB.

As can be seen from the above description, the reference indicated torque TQTB is the total torque generated from the engine under the standard operating parameter, and when the actual operating parameter is different from the standard operating parameter, the difference is actually taken. The indicated torque is also different. Therefore, the actual operating parameter is measured and the correction coefficient KT based on this is measured.
Q is calculated (block B5) and the reference indicated torque TQTB
Is multiplied by the correction coefficient KTQ (block B6) to calculate the actual indicated torque TQTR. Thereby, for example, when the engine is operated in the lean state, the indicated torque in the lean state in FIG. 7 is calculated as the actual indicated torque TQTR.

The correction coefficient KTQ is a ratio between the reference indicated torque and the actual indicated torque corresponding to the ratio between the reference operation parameter and the actual operation parameter. For example, the correction coefficient KTQAF based on the air-fuel ratio (see FIG. 4). ), A correction coefficient KTQEGR (see FIG. 5) based on the exhaust gas recirculation rate in EGR control, and a correction coefficient KTQIG (see FIG. 6) based on the retarder amount. Furthermore, the correction coefficient KT based on the outside temperature
QTA, KTQPA based on the outside air pressure, KTQCYL based on the partial cylinder operating state, etc. are also used, whereby the actual indicated torque can be accurately calculated. If the actual indicated torque TQTR is calculated as described above, only the reference indicated torque in the reference operating state and the correction coefficient KTQ corresponding to the operating parameter are needed, and the amount of data required for the actual indicated torque calculation is small. Capacity of the storage medium (ROM
The capacity is small.

On the other hand, in parallel with the calculation of the indicated torque, the engine friction torque TQFR corresponding to the detected engine intake negative pressure PB and the rotational speed Ne is calculated (block B4). The friction torque TQFR is generated from the resistance torque due to the reciprocating motion of the piston and the shaft rotation and the resistance torque due to the intake / exhaust pumping loss, and is not affected by the above operating parameters, and the engine intake negative pressure (engine load) PB and the rotation speed Ne It is decided according to. Therefore, the friction torque TQFR is set in advance in a table corresponding to the intake negative pressure PB and the rotation speed Ne, and the friction torque TQFR corresponding to the detected intake negative pressure PB and the rotation speed Ne is read from this table. It is calculated.

Then, the friction torque TQFR is subtracted from the actual indicated torque TQTR calculated as described above (block B7) to calculate the net torque TQOB. Next, the drive torque TQAC of the engine accessory device (air conditioner compressor, auxiliary machinery such as hydraulic pump) is calculated (block B8), and the net torque T is calculated.
The reference output torque TQOPB is calculated by subtracting the accessory drive torque TQAC from QOB (block B9). Further, the drive torque TQMG of the electric motor / generator M is calculated (block B10). The motor drive torque TQMG is added to the reference output torque TQOPB when the electric motor / generator M performs a motor action to assist the engine drive, and when the generator action is performed to perform energy regeneration (power generation), the reference output torque TQOPB is output. It is subtracted from the torque TQOPB (block B11), and the engine output shaft torque TQOP is calculated (block B12).

Then, the line pressure is set by the control valve CV based on the engine output shaft torque TQOP calculated in this way. The line pressure thus set corresponds exactly to the torque actually transmitted from the engine output shaft Es to the input shaft 1. Therefore, the engagement capacity of the starting clutch 5 (or the forward clutch 25, the reverse brake 27) set by using this line pressure is the minimum necessary capacity for transmitting the engine output torque to the wheel side. The engine energy (hydraulic pump drive energy) used to generate the line pressure can be suppressed to a necessary minimum to improve the fuel efficiency of the engine E. By setting the engagement capacity of the starting clutch 5 to the minimum value required to transmit the engine output torque in this way, the transmission torque will be increased when the accelerator pedal is suddenly operated or when a curb is passed over. Even if it changes abruptly, the clutch or the like will slip and the change in torque will be suppressed, improving drivability and running performance. Further, in the continuously variable transmission CVT, the pressing force of the metal V-belt 15 by the drive and driven side movable pulleys 11 and 16 can be minimized to improve the belt durability, and the transmission mechanism can be made compact and compact.

In the above embodiment, the engine E
Shows a four-cylinder type, but an engine with a number of cylinders other than this may be used, and a belt-type continuously variable transmission is shown as the transmission mechanism, but this invention is applicable to not only other continuously variable transmission mechanisms but also gear-type automatic transmission mechanisms. The invention can be applied. Further, the electric motor / generator may be arranged not only at the rear end of the engine output shaft but also at the front end thereof, or may be arranged on the transmission output shaft. Further, the present invention can be applied to a power transmission device having a configuration including only an engine without a motor generator.

In the above embodiment, the line pressure is set according to the engine output shaft torque TQOP calculated on the basis of the net torque TQOB. However, the starting clutch 5 is set according to the engine output shaft torque TQOP. It is also possible to perform control for setting the transmission torque capacity of the forward clutch 25, the reverse brake 27, and the like. It is also possible to perform control such that the shift control characteristic is changed according to the engine output shaft torque TQOP, for example, shift control of the shift map.

[0035]

As described above, according to the present invention,
The actual indicated torque is calculated by correcting the reference indicated torque in the reference operating state on the basis of the difference in the operating parameters between the actual operating state and the reference operating state. The actual indicated torque actually generated by the engine can be accurately calculated (even when the operating parameter changes), and the data necessary for this calculation corresponds to the reference indicated torque and the operating parameter in the reference operating state. Only the correction coefficient to be used, the amount of data necessary for calculating the actual indicated torque may be small, and the capacity of the storage medium (ROM capacity) may be small.

Then, by subtracting the engine friction torque from the thus calculated actual torque to calculate the net torque, the accurate net torque can be calculated under any operating parameter. In the present invention, the parameter setting device sets control parameters (for example, line pressure, transmission torque capacity, shift characteristics, etc.) based on this net torque. Therefore, for example, the engagement capacity of the clutch or the like in the speed change mechanism, which is set using the line pressure that is the control parameter, is set to be the minimum necessary capacity for transmitting the engine output torque to the wheel side. The engine energy used to create the line pressure can be minimized to improve fuel efficiency. In addition, if the clutch engagement capacity is set to the minimum value required to transmit the engine output torque, the transmission torque will change abruptly when the accelerator pedal is suddenly operated or when the vehicle goes over a curb. Even
The clutch or the like slips and the torque change is suppressed, so that the drivability and the running property are improved. Further, in the belt type continuously variable transmission, the pressing force of the belt can be minimized to improve the durability of the belt, and the transmission mechanism can be made compact and compact.

If the shift control characteristic of the transmission is also set based on the net torque accurately calculated in this way, the shift control characteristic can be set accurately. In particular, if the running road surface gradient is calculated from the net torque, running resistance, acceleration resistance, etc. calculated in this way, it is possible to set an accurate road surface gradient, and it is possible to carry out shift map control accurately according to the road surface gradient. Is.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a configuration of a power transmission device according to the present invention.

FIG. 2 is a schematic diagram showing a power transmission system of the power transmission device.

FIG. 3 is a block diagram showing a method of calculating a line pressure according to an engine output shaft torque during traveling in the power transmission device.

FIG. 4 is a graph showing an air-fuel ratio correction coefficient KTQAF used for the indicated torque correction in the above line pressure calculation.

FIG. 5 is a graph showing a reflux rate correction coefficient KTQEGR used for correction of indicated torque in the calculation of the line pressure.

FIG. 6 is a graph showing a retard amount correction coefficient KTQIG used for the indicated torque correction in the calculation of the line pressure.

FIG. 7 is an explanatory diagram showing the relationship between the indicated torque, the net torque, and the friction torque of the engine.

[Explanation of symbols]

E engine Es engine output shaft CVT continuously variable transmission (transmission mechanism) CV control valve (line pressure setting device) M Electric motor / generator 5 Start clutch 25 Forward clutch 27 Reverse brake

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Teruo Wakashiro             1-4-1 Chuo Stock Market, Wako City, Saitama Prefecture             Inside Honda Research Laboratory F term (reference) 3G084 BA32 DA27 EB09 EC03 FA11                       FA18 FA32 FA33                 3J552 MA07 MA13 NB01 PA12 PA59                       PA63 QA24C SA36 SA52                       VC01W VC03W

Claims (4)

[Claims] 1. A power transmission device comprising a speed change mechanism for speed-changing and transmitting rotational driving force from an engine, and a parameter setting device for variably setting a control parameter for operation control of the speed change mechanism. Reference indicated torque calculating means for calculating the reference indicated torque of the engine in the reference operating state based on the rotation speed and the load, and the reference operating torque based on the difference in the operating parameter between the actual operating state of the engine and the reference operating state. An actual indicated torque calculating means for correcting the reference indicated torque to calculate the actual indicated torque generated in the actual operating state, and a friction torque calculating means for calculating the friction torque of the engine based on the engine speed and the load. And the friction torque from the actual indicated torque calculated by the actual indicated torque calculating means. And a net torque calculating means for calculating the net torque of the engine by subtracting the friction torque calculated by the torque calculating means, the parameter setting device according to the net torque calculated by the net torque calculating means. The power transmission device is characterized in that the control parameter is set according to the above. 2. The speed change mechanism is configured to be operated and controlled by receiving hydraulic pressure, a line pressure supplied to the speed change mechanism is used as the control parameter, and the parameter setting device causes the net torque to be changed. The power transmission device according to claim 1, wherein the line pressure is configured to be adjusted in accordance with the above. 3. The transmission mechanism is configured to include a friction engagement element that variably sets a transmission torque capacity, the transmission torque capacity is used as the control parameter, and the parameter setting device is responsive to the net torque. The power transmission device according to claim 1, wherein the transmission torque capacity of the friction engagement element is variably set. 4. The shift mechanism is configured to perform an automatic shift based on a predetermined shift characteristic, the shift characteristic is used as the control parameter, and the parameter setting device sets the shift characteristic according to the net torque. The power transmission device according to claim 1, wherein the power transmission device is configured to be variably set.