JP4018787B2 - Vehicle driving force control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vehicular driving force control apparatus, and more specifically to an apparatus in which an internal combustion engine and an automatic transmission mounted therein are integratedly controlled to optimize fuel consumption (fuel consumption) performance.
[0002]
[Prior art]
Conventionally, when a driver depresses the accelerator pedal greatly and demands high output from a power plant when traveling on an uphill road or at a high speed, the engine load becomes high. Fuel control is performed so that the amount of fuel is increased and the exhaust gas temperature is lowered compared to the air-fuel ratio. As a result, there is a problem that fuel consumption and emission performance deteriorate.
[0003]
Therefore, for example, in Japanese Examined Patent Publication No. 7-81535, a fuel saving operation means (switch) operated during fuel saving operation is provided, and when it is operated, it is in a high load region where a high load increase is required. It has been proposed that the throttle valve is controlled to be equal to or less than the opening degree required in the high load region below the load state immediately before being determined.
[0004]
[Problems to be solved by the invention]
However, in the above-described conventional technology, a high load determination intended to improve fuel efficiency is performed via a switch operated by the driver, which is complicated in configuration and has a disadvantage that requires operation by the driver. It was.
[0005]
The object of the present invention is to eliminate the above-mentioned drawbacks of the prior art, so that a high load determination intended to improve fuel efficiency can be performed appropriately, so that the required output can be realized without deteriorating the fuel efficiency and emission performance. Another object of the present invention is to provide a vehicle driving force control device.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, according to a first aspect of the present invention, there is provided a vehicular driving force control apparatus including an automatic transmission and an internal combustion engine, wherein the vehicle includes at least an accelerator opening and a vehicle speed. The vehicle should output based on the operating state, the operating state detecting means for detecting the operating state of the internal combustion engine including at least the engine warm-up state, the engine speed, and the engine load, the detected accelerator opening, and the vehicle speed. Target driving force calculating means for calculating a target driving force, output calculating means for calculating an output of the internal combustion engine and a gear ratio of the automatic transmission based on the calculated target driving force and the detected operating state, Actuator control means for controlling an actuator for adjusting the output of the internal combustion engine based on the calculated output, and the automatic transmission based on the calculated gear ratio Shift control means for controlling, provided with a, the high-load operating condition When detected continuously for a predetermined time or longer, The calculated gear ratio can achieve the calculated target driving force. Correction means for determining that there is no change and correcting the gear ratio so that the target driving force can be achieved It comprised so that it might be equipped with. Accordingly, it is possible to appropriately perform the high load determination intended to improve the fuel consumption performance, and thus to achieve the required output without deteriorating the fuel consumption and the emission performance.
[0007]
That is, it is possible to appropriately determine the high load according to the actual vehicle running state. Therefore, since the vehicle can be driven with a driving force equivalent to the driving force generated when fuel increase is performed, the fuel efficiency can be improved without deteriorating drivability. Further, since the control is performed with the stoichiometric air-fuel ratio, the emission performance is also improved.
[0009]
Claim 2 The output calculation means is configured to cause the internal combustion engine to perform a fully open increase avoidance operation when correcting the speed ratio. As a result, the range in which the internal combustion engine is operated at the stoichiometric air-fuel ratio can be expanded, and fuel efficiency and emission performance can be improved.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the accompanying drawings.
[0011]
FIG. 1 is a schematic view generally showing a vehicle driving force control apparatus according to the present invention. In the case of the illustrated embodiment, a belt-type continuously variable transmission (CVT) is provided as an automatic transmission.
[0012]
In the figure, reference numeral 10 denotes an internal combustion engine (hereinafter referred to as “engine”), more specifically, a main body thereof. A throttle valve 14 is disposed in an intake pipe 12 connected to the engine 10. The throttle valve 14 is disconnected from the accelerator pedal 16 disposed on the floor surface of a vehicle driver's seat (not shown), connected to a pulse motor 18 and opened and closed by its output. The engine 10 is provided with an EGR (exhaust circulation) mechanism (not shown).
[0013]
An output shaft (crankshaft) 20 of the engine 10 is connected to a belt type continuously variable transmission 24 (CVT, hereinafter referred to as “transmission”). More specifically, the output shaft 20 of the engine 10 is connected to the input shaft 28 of the transmission 24 via the dual mass flywheel 26.
[0014]
The transmission 24 includes a metal V-belt mechanism 32 disposed between the input shaft 28 and the counter shaft 30, and a planetary gear type forward / reverse switching mechanism disposed between the input shaft 28 and the drive-side movable pulley 34. 36, and a starting clutch 42 disposed between the counter shaft 30 and the differential mechanism 40. The power transmitted to the differential mechanism 40 is transmitted to left and right drive wheels (not shown) via a drive shaft (not shown).
[0015]
The metal V-belt mechanism 32 includes a drive-side movable pulley 34 disposed on the input shaft 28, a driven-side movable pulley 46 disposed on the counter shaft 30, and a metal V-belt wound between both pulleys. 48. The drive-side movable pulley 34 includes a fixed pulley half 50 disposed on the input shaft 28 and a movable pulley half 52 movable relative to the fixed pulley half 50 in the axial direction.
[0016]
On the side of the movable pulley half 52, a drive side cylinder chamber 54 is formed surrounded by a cylinder wall 50a coupled to the fixed pulley half, and is supplied to the drive side cylinder chamber 54 via an oil passage 54a. A hydraulic pressure is generated to generate a side pressure that moves the movable pulley half 52 in the axial direction.
[0017]
The driven-side movable pulley 46 includes a fixed pulley half 56 disposed on the counter shaft 30 and a movable pulley half 58 that can move relative to the fixed pulley half 56 in the axial direction. A driven-side cylinder chamber 60 is formed on the side of the movable pulley half 58 by being surrounded by a cylinder wall 56a coupled to the fixed pulley half 56, and is supplied to the driven-side cylinder chamber 60 via an oil passage 60a. A side pressure that moves the movable pulley half 58 in the axial direction is generated by the hydraulic pressure.
[0018]
A regulator valve group 64 that determines the pulley control hydraulic pressure supplied to the drive side cylinder chamber 54 and the driven side cylinder chamber 60, and a speed change control valve group 66 that supplies the pulley control hydraulic pressure to the cylinder chambers 54, 60 are provided. As a result, an appropriate pulley side pressure that does not cause slippage of the V-belt 48 is set, the pulley widths of both pulleys 34 and 46 are changed, and the winding radius of the V-belt 48 is changed to change the gear ratio. Change steplessly.
[0019]
The planetary gear type forward / reverse switching mechanism 36 includes a sun gear 68 coupled to the input shaft, a carrier 70 coupled to the fixed pulley half 50, a ring gear 74 that can be fixedly held by a reverse brake 72, a sun gear 68, and a carrier. And a forward clutch 76 that can be coupled to 70.
[0020]
When the forward clutch 76 is engaged, all the gears rotate together with the input shaft 28, and the drive pulley 34 is driven in the same direction (forward direction) as the input shaft 28. When the reverse brake 72 is engaged, the ring gear 74 is fixed and held so that the carrier 70 is driven in the opposite direction to the sun gear 68 and the drive pulley 34 is driven in the opposite direction (reverse direction) to the input shaft 28. Is done. When the forward clutch 76 and the reverse brake 72 are both released, the power transmission via the forward / reverse switching mechanism 36 is cut off, and the power transmission between the engine 10 and the drive side drive pulley 34 is performed. I will not be broken.
[0021]
The start clutch 42 is a clutch that controls on (engagement) / off (release) power transmission between the counter shaft 30 and the differential mechanism 40. When the start clutch 42 is turned on (engaged), the metal V belt mechanism 32 changes the speed. The engine output is divided and transmitted to the left and right wheels (not shown) by the differential mechanism 40 via gears 78, 80, 82, and 84. When the starting clutch 42 is off (released), the transmission is in a neutral state.
[0022]
The operation control of the start clutch 42 is performed by a clutch control valve 88, and the operation control of the reverse brake 72 and the forward clutch 76 in the forward / reverse switching mechanism 36 is performed according to the operation of a manual shift lever (not shown). Is done.
[0023]
Control of these valve groups is performed based on a control signal from a transmission control unit 100 formed of a microcomputer.
[0024]
Here, a crank angle sensor 102 is provided at an appropriate position such as near the cam shaft (not shown) of the engine 10, and a signal proportional to the crank angle (the engine rotational speed NE is calculated by counting the crank angle sensor 102). Is output. An absolute pressure sensor 104 is provided at an appropriate position downstream of the throttle valve 14 in the intake pipe 12 to output a signal P proportional to the intake pipe absolute pressure (engine load) PBA, and to a cylinder block (not shown). A water temperature sensor 106 is provided at an appropriate position and outputs a signal proportional to the engine cooling water temperature TW.
[0025]
In addition, a throttle opening sensor 108 is provided in the vicinity of the throttle valve 14 and outputs a signal proportional to the throttle opening θTH, and an accelerator opening sensor 110 is provided in the vicinity of the accelerator pedal 16, A signal proportional to the depressed accelerator opening ACC is output.
[0026]
In the transmission 24, a rotation speed sensor 114 is provided near the input shaft 28 and outputs a signal proportional to the rotation speed NDR of the input shaft 28, and a rotation speed sensor 116 is provided near the driven pulley 46. A signal proportional to the rotational speed of the driven pulley 46, that is, the rotational speed NDN of the input shaft (counter shaft 30) of the starting clutch 42 is output. A rotation speed sensor 118 is provided near the gear 78 and outputs a signal proportional to the rotation speed of the gear 78, that is, the rotation speed NOUT of the output shaft of the start clutch 42.
[0027]
Further, a vehicle speed sensor 122 is provided in the vicinity of a drive shaft (not shown) connected to the differential mechanism 40 and outputs a signal proportional to the vehicle speed VLVH. Further, a shift lever position switch 124 is provided in the vicinity of a shift lever (not shown) on the driver's seat floor, and a signal proportional to a range position (D, N, P,...) Selected by the driver. Is output.
[0028]
As described above, this apparatus includes the transmission control unit 100 and also includes the engine control unit 200 formed of a microcomputer. Among the sensor groups described above, outputs of the crank angle sensor 102, the absolute pressure sensor 104, the water temperature sensor 106, and the throttle opening sensor 108 are input to the control units 100 and 200.
[0029]
The apparatus also includes an integrated control unit 300 formed of a microcomputer. The outputs of the accelerator opening sensor 110 and the vehicle speed sensor 122 in the sensor group described above are input to the integrated control unit 300.
[0030]
FIG. 2 is an explanatory block diagram functionally showing the configuration of the integrated control unit 300.
[0031]
The integrated control unit 300 includes a target load (driving force) determination unit 300a, an engine operation system switching determination unit 300b, and a target engine torque / target gear ratio calculation unit 300c. The target load (driving force) determination unit 300a inputs the outputs ACC and VLVH of the accelerator opening sensor 110 and the vehicle speed sensor 122, and predetermined characteristics (map) as described later based on the detected accelerator opening ACC and the vehicle speed VLVH. The target load to be output by the vehicle, more specifically, the target driving force FCMD is calculated.
[0032]
The engine operation method switching determination unit 300b performs engine operation method switching determination based on the vehicle speed VLVH, the target driving force FCMD (FCMDREG), and an engine operation option signal (engine operation state signal) from the engine control unit described later. The system command value is sent to the engine control unit 200 and the target engine torque / target gear ratio calculation unit 300c.
[0033]
The target engine torque / target speed ratio calculation unit 300c uses a map corresponding to the corresponding engine operation method in a plurality of maps (operation characteristics) prepared based on the engine operation method command value, and the target engine torque and more Specifically, the target throttle opening THCMD is determined and sent to the throttle control unit 400. The throttle control unit 400 determines and drives the control value of the pulse motor 18 according to the target throttle opening THCMD. As a result, the engine is controlled to a desired torque.
[0034]
Further, the target engine torque / target gear ratio calculation unit 300c uses the corresponding maps among the maps (driving characteristics) prepared based on the engine operation method command value, and more specifically, the target gear ratio, more specifically, A target NDR (NDRCMD), that is, a target value of the input rotational speed NDR is determined and sent to the transmission control unit 100.
[0035]
As described above, the transmission control unit 100 drives the movable pulleys 34 and 46 to control the gear ratio so as to achieve the target NDR. Here, the target NDR is the target rotational speed of the drive-side movable pulley 34 of the transmission 24, and the gear ratio is uniquely determined and controlled by defining the target NDR with respect to the vehicle speed VLVH.
[0036]
A plurality of maps (operation characteristics) prepared by the target engine torque / target gear ratio calculation unit are provided for each operation method, lean burn (lean combustion) operation, EGR operation with stoichiometric, stoichiometric, and theoretical sky. It consists of four types of operation without EGR at the fuel ratio and high-load full-open operation. Naturally, the fuel consumption increases in the above order. In order to achieve the best fuel efficiency, these maps have a throttle opening and a gear ratio (ratio) according to the vehicle speed and target driving force FCMD, more precisely, a combination of the throttle opening and the gear ratio (ratio) in advance. Determined by experiment.
[0037]
Next, the operation of this apparatus will be described.
[0038]
FIG. 3 is a flowchart showing the operation. The illustrated program is an operation performed by the integrated control unit 300, and is executed every predetermined time, for example, 20 msec.
[0039]
First, input information processing is performed in S10.
[0040]
FIG. 4 is a subroutine flow chart showing the processing.
[0041]
In the following, the vehicle speed VLVH detected by the vehicle speed sensor 122 is read in S100, the accelerator opening ACC detected by the accelerator opening sensor 110 is read in S102, and the option signal sent from the engine control unit 200 is advanced in S104. Is read.
[0042]
The engine control unit 200 can introduce (operate) EGR or perform lean burn operation from parameters indicating the operation state such as the engine coolant temperature TW indicating the warm-up state of the engine 10, the engine speed NE, and the engine load PBA. Is sent to the engine operation method switching determination unit 300b as an option signal.
[0043]
Specifically, the option signal is flag FLG. SLBOK (lean burn operation), FLG. EGROK (EGR operation) and FLG. It consists of PBWOTSTB (full-open increased operation standby), and the engine operation system switching determination unit 300b receives the signal by referring to these bits. When these bits are set to 1, it indicates that lean burn operation, EGR operation is possible, or that the fully-open increase operation standby is in progress, and when it is reset to 0, it indicates the case.
[0044]
Returning to FIG. 3, the process then proceeds to S12 to calculate the target driving force FCMD.
[0045]
FIG. 5 is a subroutine flow chart showing the work.
[0046]
In the following, the vehicle speed VLVH is read in S200, the process proceeds to S202, the accelerator opening ACC is read, the process proceeds to S204, and the map (characteristic) shown in FIG. 6 is searched from the read value to determine the target driving force FCMD.
[0047]
FIG. 7 is a subroutine flow chart showing the operation in more detail.
[0048]
FIG. 8 is an explanatory block diagram for explaining the operation of FIG. The target load (driving force) determining unit 300a includes a steady driving force calculating unit A and a dynamic characteristic calculating unit B as shown in the figure.
[0049]
Explained below, from the vehicle speed VLVH and the accelerator opening degree ACC read in S300, a fully open driving force map, a fully closed driving force map, and a partial driving force ratio map whose characteristics are shown in FIG. 8 are retrieved, and the fully open driving force FCMDWOT [ kgf], fully closed driving force FCMDOFF [kgf], and partial driving force ratio (target driving force normalized value) FREGMAP [%].
[0050]
The fully open driving force map and the fully closed driving force map define the maximum driving force FCMDWOT and the minimum driving force FCMDOFF that can be realized for the vehicle speed VLVH. The partial driving force ratio (target driving force normalized value) map defines the ratio of the driving force to the accelerator opening ACC at the vehicle speed VLVH, normalized between the maximum and minimum driving forces.
[0051]
Further, when the accelerator pedal depression speed is high, that is, when the accelerator opening change ΔACC (the first-order differential value of the accelerator opening ACC) is larger than a predetermined value, the driver instantaneously wants a larger driving force. From the accelerator opening change ΔACC, a kickdown ratio addition amount DFREKD1 corresponding to the kickdown operation is retrieved.
[0052]
Next, in S302, the difference FCMDSPAN is calculated by subtracting the fully closed driving force FCMDWOT from the fully opening driving force FCMDWOT, and the flow advances to S304. Multiply and add the full-close driving force FCMDOFF to the product to obtain the steady-state target driving force FCMDMAP.
[0053]
Next, in S306, FCMD (k-1), that is, the previous value of FCMD is subtracted from the obtained value FCMDMAP to obtain a difference SFCMD. Here, (k-1) indicates the previous sample time in the Z transformation (discrete system), more specifically, the value at the previous execution time of the program of FIG. For simplification of illustration, the value (k) is omitted from the current value.
[0054]
Next, in S308, a dynamic characteristic setting map showing the characteristic in FIG. 8 is retrieved from the obtained difference SFCMD to obtain a value DFCMDTMP. The dynamic characteristic setting map defines a target driving force response adjustment term map value DFCMDTMP for a deviation SFCMD between the previous target driving force FCMD (k-1) and the current target driving force FCMD.
[0055]
Next, in S310, a transient response adjustment map whose characteristics are shown in FIG. 8 is retrieved from the vehicle speed VLVH to obtain a value KDFCMD. The transient response adjustment map defines a correction coefficient KDFCMD for the target driving force response adjustment term DFCMDTMP with respect to the vehicle speed. Next, in S312, the target driving force response adjustment term DFCMD is calculated by multiplying the values DFCMDTMP and KDFCMD obtained.
[0056]
Next, the routine proceeds to S314, where it is determined whether the detected accelerator opening ACC exceeds a predetermined value APDEGOFF (fully closed judgment value), in other words, whether the accelerator opening is substantially not fully closed. If it is determined that there is not, the process proceeds to S316, and the sum of FCMDMAP and DFCMD, that is, the value after dynamic characteristic adjustment is set as the target driving force FCMD. That is, the value before dynamic characteristic adjustment is set as the target driving force FCMD.
[0057]
Next, in S320, the target driving force FCMD after dynamic characteristic adjustment is processed into an amount FCMDREG (%) normalized using FCMDOFF and FCMDSPAN, and the program is terminated.
[0058]
To explain the above, when the driving force characteristics are mapped to the vehicle speed and the accelerator opening, the target driving force is normalized, and the maximum driving force that can be achieved by the vehicle is high at low vehicle speeds and high. Since the vehicle speed is low, if the map is defined by the actual driving force, the search resolution becomes coarse on the minimum driving force side if the grid points of the map are set based on the maximum driving force. For this reason, the whole was normalized and expressed. As a result, the output resolution can be made the same in accordance with the accelerator opening at any vehicle speed.
[0059]
Moreover, the reason why the target driving force calculation block is configured to be divided into the steady driving force calculation unit A and the dynamic characteristic calculation unit B as shown in FIG. 8 is as follows.
[0060]
That is, if the change speed of the target driving force is too large, the engine torque response and the transmission speed of the transmission cannot follow the requirements, and the requirements for the set characteristics may not be satisfied. In this case, it is conceivable to obtain an actual driving force with respect to the target driving force and perform feedback control by engine torque correction, but the configuration becomes complicated.
[0061]
In this case, the relationship between the preset engine torque and the gear ratio (ratio) is shifted, and the driving point with the best fuel efficiency is shifted. In fact, the driver does not seek a sudden step-like change in driving force, and gradually responding to the required output in the steady state matches the driver's request, and the drivability is good.
[0062]
Therefore, as shown in FIG. 8, the steady driving force calculation unit A and the dynamic characteristic calculation unit B are configured separately, and the required (target) driving force is to be realized as a steady characteristic at a certain accelerator opening and vehicle speed by the former. In addition to the calculation, a transient characteristic that defines how to respond until the drive is calculated by the latter, and the change speed of the target drive force is limited.
[0063]
That is, the dynamic characteristic calculation unit calculates the target driving force by correcting the steady driving force obtained by the steady driving force calculation unit so as to satisfy the dynamic characteristics of the driving force in consideration of the response characteristics of the engine and the transmission. . With this configuration, it is possible to always follow and control the combination of the engine torque and the gear ratio (ratio) with the best fuel efficiency while maintaining good drivability.
[0064]
In addition, when the accelerator opening is fully closed, it is possible to quickly grasp the intention of deceleration by setting the target driving force only to the steady characteristic, and depending on the vehicle speed when the accelerator opening is not fully closed. By adjusting the transient response characteristic, the driving force characteristic of the vehicle can be freely set with a simple configuration.
[0065]
Returning to FIG. 3, the process proceeds to S <b> 14 to determine the engine operation method.
[0066]
This is an operation method option signal sent from the engine control unit 200, that is, the flag FLG. EGROK and FLG. Based on bits such as SLBOK, the driving method with the best fuel efficiency is selected from these options. More specifically, an area map (characteristic) set as shown in FIG. 9 is searched based on the obtained target driving force FCMD and vehicle speed VLVH.
[0067]
As shown in FIG. 9, the driving method having the best fuel efficiency performance is selected from the vehicle load such as the target driving force and the vehicle speed, as shown in FIG. decide.
[0068]
In addition, when the lean burn operation and the stoichiometric air-fuel ratio EGR operation are compared with each other in the driving method with good fuel efficiency, as shown in FIG. 10, when viewed at the same vehicle speed and the same driving force, the lean burn has a low ratio (large gear ratio). Is the case. However, depending on the situation, as shown in FIG. 11, the fuel efficiency may be better when the engine is operated at the stoichiometric air-fuel ratio and at a high ratio (small gear ratio) at the OD end. Therefore, the driving method with the best fuel consumption performance, that is, the minimum in each combination of vehicle speed and driving force is obtained in advance and mapped as shown in FIG.
[0069]
FIG. 12 is a subroutine flowchart showing the engine operation method determination work.
[0070]
Explaining below, in S400, it is determined from the vehicle speed and the target driving force whether or not a preset full-open increase avoidance operation reset region has been entered. FIG. 13 is an explanatory diagram of the area.
[0071]
The fully-open increase avoidance operation reset region means that when the vehicle speed and the target driving force are within a predetermined range, even if the engine torque is not operated with the torque of the region where the fully-open increase operation is performed, The driving force can be realized by the lean burn operation, the EGR operation at the stoichiometric air-fuel ratio, and the operation without the EGR control at the stoichiometric air-fuel ratio. So create a reset signal.
[0072]
Therefore, when the result in S400 is negative, the program proceeds to S402, in which the above-described full-open increase avoidance operation method is selected and the bit of the full-open increase avoidance reset flag is reset to zero. On the other hand, if the determination is affirmative, the process proceeds to S404 and the bit of the flag is set to 1.
[0073]
Next, in S406, the flag FLG. It is determined whether or not the bit of PBWOTSB (waiting for fully open increase operation) is set to 1, that is, whether or not the engine is waiting for fully open increase operation.
[0074]
The fact that the flag bit is set to 1 means that the target air-fuel ratio enrichment operation mode is about to be entered sooner during full-open increase operation standby, more specifically for engine protection, as described above. Show. When the result in S406 is affirmative, the routine proceeds to S408, where the operation mode is set to a fully open increase avoidance operation, more specifically, an operation mode in which the gear ratio is set so as to avoid the fully open increase amount.
[0075]
To explain this, at high loads, in general, in order to protect the exhaust purification device from high-temperature exhaust gas, the fuel injection amount is increased more than the stoichiometric air-fuel ratio to lower the exhaust temperature. Then, fuel efficiency and emission performance are deteriorated. From this intention, in this device, even when the driver demands a high output (load), the fully-open increase operation is avoided as much as possible.
[0076]
On the other hand, when the result in S406 is NO, the program proceeds to S410, in which the flag FLG. It is determined whether or not the SLBOK (lean burn operation) bit is set to 1, in other words, whether or not the lean burn operation is possible. If the determination is affirmative, the flow proceeds to S412 to allow the lean burn from the target driving force and the vehicle speed. It is determined whether it is in the area.
[0077]
FIG. 16 shows the characteristics of the lean burn permission area. This characteristic is set in advance so as to satisfy not only fuel consumption performance but also emission performance and drivability. Therefore, although it is not necessarily the minimum in terms of fuel consumption performance, if it is desired to avoid lean burn operation for any reason, it can be easily avoided by changing this characteristic. .
[0078]
When the result in S412 is affirmative, the program proceeds to S414 and the operation method is set to lean burn operation. On the other hand, when the result in S410 or S412 is NO, the program proceeds to S416, where the flag FLG. It is determined whether or not the EGROK bit is set to 1. If the determination is affirmative, the process proceeds to S418, and the operation method is set to the EGR operation while controlling the air-fuel ratio to the stoichiometric air-fuel ratio.
[0079]
S41 6 If the result is NO, specifically, if the combustion becomes unstable due to the introduction of EGR as in the cold state, the process proceeds to S420, and the EGR is executed while controlling the air-fuel ratio to the stoichiometric air-fuel ratio. Do not drive.
[0080]
Subsequently, the process proceeds to S422, in which an operation method is instructed to the engine control unit 200, and the process proceeds to S424, where a fully open increase avoidance operation reset signal (determined in S402, S404) is transmitted to the engine control unit 200. As a result, the flag FLG. The bit of PBWOTSTB is reset to 0. Next, in S426, the driving method is transmitted to the target engine torque / target gear ratio calculation unit 300c.
[0081]
FIG. 14 is a subroutine flow chart showing processing performed by the engine control unit 200 based on the above-described operation command.
[0082]
Explaining below, it is determined in S500 whether the engine load (absolute pressure in the intake pipe PBA) exceeds the full opening increase threshold value, in other words, whether the engine is in a high load state. Standby timer (down counter) The (Star G And proceed to S504 to perform time measurement. This is shown in FIG. 15 time chart.
[0083]
On the other hand, when the result in S500 is affirmative, the program proceeds to S506, in which the count value of the full-open increase waiting timer is not less than a predetermined value. under If the result is affirmative, the program proceeds to S508, in which the fully-open increase waiting flag FLG. Set the PBWOTSTB bit to 1. As a result, as described above, the integrated control unit 300 is informed that it is waiting for the fully opened increase operation. If the determination at S506 is No, S508 is skipped.
[0084]
Subsequently, the routine proceeds to S510, where it is determined whether or not the count value of the fully opened increase waiting timer has reached zero, and when the result is affirmative, the routine proceeds to S512 where the operation method is set to the fully opened increment, that is, the flag FLG. Set the PBWOTSTB bit to 1. If the result in S510 is NO, S512 is skipped.
[0085]
Subsequently, the process proceeds to S514, where it is determined whether or not the bit of the fully open increase avoidance reset flag is set to 1 (set / reset in the process of FIG. 12). Set the bits of If the determination is negative, S516 is skipped.
[0086]
With the configuration described above, when the fully open increase avoidance operation mode is entered, the gear ratio and engine torque are changed, and the engine load is shifted to the high rotation low load side that does not require full open, so that the fully open increase is not required. Is done.
[0087]
In other words, even when performing the full opening increase avoidance operation, the shift to a driving point with good fuel consumption performance with the same driving force as in the case of full opening increase with high load engine torque at low rotation, the fuel efficiency performance is not affected without deterioration of drivability. Can be improved. Specifically, as will be described later with reference to FIG. 21, fuel efficiency (FE) is obtained in a vehicle speed range of 30 km / h, a target driving force (normalized value) in a range of 40% to 60% in black, that is, in a low vehicle speed and high load region. ) Can be improved. Further, in the fully open increase avoidance operation, since the operation is performed at the stoichiometric air-fuel ratio, the range of operation at the stoichiometric air-fuel ratio can be expanded, and the emission performance can be improved.
[0088]
That is, the engine is configured to detect a high load operation state of the engine based on the detected operation state, and to determine whether or not the target driving force can be achieved when the high load operation state is detected. Further, when it is determined that the target driving force cannot be achieved, the gear ratio is configured to be greatly corrected so that the target driving force can be achieved. Accordingly, it is possible to appropriately determine a high load according to the actual vehicle running state, and it is possible to run with a driving force equivalent to the driving force generated when fuel increase is performed, so that the fuel efficiency is not deteriorated without deteriorating drivability. Performance can be improved. Further, since the control is performed with the stoichiometric air-fuel ratio, the emission performance is also improved. As described above, it is possible to appropriately perform the high load determination intended to improve the fuel efficiency and achieve the required output without deteriorating the fuel efficiency and the emission performance.
[0089]
Returning to the flowchart of FIG. 3, the process proceeds to S16, and the target throttle opening THCMD is calculated according to the determined operation method.
[0090]
FIG. 17 is a subroutine flow chart showing the work.
[0091]
In the following, the map (characteristic) corresponding to the driving method selected in S600 is switched (selected), the process proceeds to S602, the vehicle speed VLVH is read, the process proceeds to S604, and the target driving force FCMD and its normalized amount FCMDREG are read. In S606, the target throttle opening THCMD is calculated. FIG. 18 shows the characteristics. The reason why the map search is performed using the normalized value FCMDREG instead of the final value FCMD is that, as described above, data can be set with the same accuracy regardless of the vehicle speed, as described above.
[0092]
Returning to the flowchart of FIG. 3, the process then proceeds to S18 to calculate the target NDR (NDRCMD).
[0093]
FIG. 19 is a subroutine flow chart showing the work.
[0094]
In the following, the map (characteristic) corresponding to the driving method selected in S700 is switched (selected), the process proceeds to S702, the vehicle speed VLVH is read, the process proceeds to S704, and the target driving force FCMD and its normalized amount FCMDREG are read. , The process proceeds to S706, and the target NDR (NDRCMD) is calculated. FIG. 20 shows the characteristics. For the same reason, a map search is performed from the normalized amount FCMDREG.
[0095]
In the flow chart of FIG. 3, the process subsequently proceeds to S20, and the output, that is, the calculated engine operation method command value, the target throttle opening THCMD, the target NDR (NDRCMD), the engine control unit 200, the throttle control unit 400, and the transmission Output to the controller 100.
[0096]
As a result, the engine control unit 200 operates the engine in accordance with the commanded method, and the throttle opening control unit drives the pulse motor 18 to achieve the target throttle opening, more specifically, the required engine output.
[0097]
Further, the transmission control unit 100 controls the gear ratio so as to achieve the target NDR. More specifically, the hydraulic pressure is supplied to the drive-side movable pulley 34 and the driven-side movable pulley 46, and feedback control is performed so that the drive pulley rotation NDR (input rotation speed) becomes the target NDR.
[0098]
As described above, in this embodiment, in the vehicle driving force control device equipped with the automatic transmission (belt type continuously variable transmission 24) and the internal combustion engine (engine 10), at least the accelerator opening ACC, the vehicle speed. Driving state detecting means for detecting the driving state of the vehicle including VLVH and the driving state of the internal combustion engine including at least the engine warm-up state, engine speed, and engine load (accelerator opening sensor 110, vehicle speed sensor 122, etc. S10). ), Target driving force calculation means (target load (driving force) determination unit 300a, S12) for calculating the target driving force FCMD to be output from the vehicle based on the detected accelerator opening and vehicle speed, the calculated Based on the target driving force and the detected operating state, the output THCMD of the internal combustion engine and the gear ratio (target NDR) of the automatic transmission are calculated. Output calculation means (engine control unit 200, target engine torque / target speed ratio calculation unit 300c, S16, S18, S500 to S516), an actuator (pulse motor) that adjusts the output of the internal combustion engine based on the calculated output 18) Actuator control means (throttle control section 400) for controlling, and shift control means (transmission control section 100) for controlling the automatic transmission based on the calculated gear ratio, and the detected High load operation state detection means (S500) for detecting the high load operation state of the internal combustion engine based on the operation state, the high load operation state is When detected continuously for a predetermined time or longer, The calculated gear ratio can achieve the calculated target driving force. Correction means for determining that there is no change and correcting the gear ratio so that the target driving force can be achieved (S504 to S516 , S18 ).
[0100]
Further, the output calculation means is configured to cause the internal combustion engine to perform a full opening increase avoidance operation when correcting the gear ratio (S504 to S516).
[0101]
Accordingly, it is possible to appropriately perform the high load determination intended to improve the fuel consumption performance, and thus to achieve the required output without deteriorating the fuel consumption and the emission performance. Further, since the control is performed with the stoichiometric air-fuel ratio, the emission performance is also improved.
[0102]
In addition, among driving method options that can be driven when considering only the engine, the driving method that achieves the best (minimum) fuel consumption based on the required load of the vehicle, specifically the target driving force (and vehicle speed). The combination of target torque (target driving force) and gear ratio according to the switched operation method can be determined, so that possible engine operation is possible in all operating conditions including cold and warm-up. Within the constraints of the system, a combination of engine torque and gear ratio that always achieves the best fuel efficiency with respect to the target driving force can be obtained, and the fuel efficiency can be minimized. In FIG. 21, the black portion indicates a region where the fuel efficiency has been improved. Thus, the fuel efficiency performance in the low vehicle speed, high load region where the vehicle speed is around 30 km / h and the target driving force (normalized value) is 40% to 60%. Can be significantly improved.
[0103]
In addition, the absolute value of the maximum driving force that can be generated by the vehicle usually decreases as the vehicle speed increases, but the target driving force is normalized between the maximum value and the minimum value, and the map is used using this value. By performing the search, it is possible to improve the search resolution of the target engine torque and the gear ratio in the entire region from the low vehicle speed to the high vehicle speed.
[0104]
Further, by obtaining the target driving force from the steady characteristic component and the transient characteristic component, the driving force corresponding to the actual driving state of the vehicle can be obtained with high accuracy.
[0105]
In the above-described embodiment, the target driving force is obtained by searching a map set in advance, but may be obtained by calculation.
[0106]
Further, although the throttle opening is shown as the target output of the engine, it may be a fuel consumption amount, an intake air amount, or the like. Although the transmission control value is indicated by NDR (input rotation speed), it may be a gear ratio or its changing speed.
[0107]
In the above-described embodiment, the engine output varying method is performed by the target throttle opening THCMD of the electronically controlled throttle valve. However, in the recently proposed direct injection engine or diesel engine, the target engine torque And the fuel amount and the target air-fuel ratio may be controlled according to the torque.
[0108]
Further, when the engine is a direct injection engine, any information capable of the super lean burn operation state by stratified combustion may be added to the above-described option signal.
[0109]
Moreover, although the metal belt type was used as the continuously variable transmission, a rubber belt type or a toroidal type may be used. Moreover, you may comprise so that the optimal gear stage of not only a continuously variable transmission but a stepped transmission may be selected. The slip ratio of the lock-up clutch may be replaced.
[0110]
That is, as a transmission, not only a continuously variable transmission but also an automatic transmission with a torque converter can be used. In that case, the gear stage of the stepped transmission is switched, or the lockup clutch is turned on / off. The engine operating region, the gear position, and the lockup clutch capacity control value may be determined in consideration of the difference in driving force due to the above, the fully open increase avoidance region, or the fuel consumption rate during WOT.
[0111]
The configuration of the transmission is not limited to that shown in the figure, and a torque converter may be connected to the output shaft 20 of the engine 10, and a torque converter may be used instead of the starting clutch 42. Further, the dual mass flywheel 26 may be removed.
[0112]
【The invention's effect】
According to the first aspect of the present invention, it is possible to appropriately perform the high load determination intended to improve the fuel consumption performance, and thus to achieve the required output without deteriorating the fuel consumption and the emission performance.
[0113]
That is, it is possible to appropriately determine the high load according to the actual vehicle running state. Therefore, since the vehicle can be driven with a driving force equivalent to the driving force generated when fuel increase is performed, the fuel efficiency can be improved without deteriorating drivability. Further, since the control is performed with the stoichiometric air-fuel ratio, the emission performance is also improved.
[0115]
Claim 2 In the term, the range in which the internal combustion engine is operated at the stoichiometric air-fuel ratio can be expanded, and the fuel efficiency and emission performance can be improved.
[Brief description of the drawings]
FIG. 1 is a schematic view showing a vehicle driving force control apparatus according to the present invention as a whole.
FIG. 2 is an explanatory block diagram functionally showing the apparatus of FIG. 1;
FIG. 3 is a flowchart showing the operation of the apparatus of FIG. 1;
4 is a subroutine flow chart showing input processing in the flow chart of FIG. 3. FIG.
FIG. 5 is a subroutine flowchart showing a target driving force calculation process in the flowchart of FIG. 3;
6 is an explanatory diagram showing characteristics of a map used for calculation in the flow chart of FIG. 5. FIG.
7 is a subroutine flow chart showing in more detail the target driving force calculation process in the flow chart of FIG.
FIG. 8 is an explanatory block diagram functionally showing the processing of the flow chart of FIG. 7;
FIG. 9 is an explanatory graph for explaining engine operation method determination processing in the flowchart of FIG. 3;
FIG. 10 is a similar explanatory graph for explaining the engine operation method determination processing of the flow chart of FIG. 3;
FIG. 11 is a similar explanatory graph for explaining the engine operation method determination processing of the flow chart of FIG. 3;
12 is a subroutine flow chart showing an engine operation method determination process of the flow chart of FIG. 3;
13 is an explanatory graph showing a fully-open increase avoidance operation reset region used in the processing of the flowchart of FIG.
14 is a flowchart showing processing of an engine control unit performed in parallel with the processing of the flowchart of FIG.
15 is a time chart for explaining the processing of the flowchart of FIG. 12 and the flowchart of FIG.
16 is an explanatory graph showing a lean burn operation permission region used in the processing of the flowchart of FIG.
FIG. 17 is a subroutine flow chart showing a target throttle opening calculation process in the flow chart of FIG. 3;
FIG. 18 is an explanatory graph showing the characteristics of a map used in the processing of the flowchart of FIG.
FIG. 19 is a subroutine flow chart showing a target NDR calculation process of the flow chart of FIG. 3;
FIG. 20 is an explanatory graph showing characteristics of a map used in the processing of the flowchart of FIG.
FIG. 21 is an explanatory graph showing an improvement in fuel consumption obtained by a fully open increase avoidance operation performed in the process of the flowchart of FIG. 12;
[Explanation of symbols]
10 Internal combustion engine (engine body)
14 Throttle valve
16 Accelerator pedal
24 belt type continuously variable transmission (transmission)
28 Transmission input shaft
30 Transmission countershaft
32 Metal V-belt mechanism
36 Planetary gear type forward / reverse switching mechanism
42 Starting clutch
100 Transmission control unit
104 Absolute pressure sensor
106 Water temperature sensor
108 Throttle opening sensor
110 Accelerator position sensor
122 Vehicle speed sensor
200 Engine control unit
300 Integrated control unit
300a Target load (driving force) determination unit
300b Engine operation system switching judgment part
300c Target engine torque / target gear ratio calculation unit
400 Throttle controller

Claims (2)

In a vehicle driving force control device equipped with an automatic transmission and an internal combustion engine,
a. An operating state detecting means for detecting an operating state of the vehicle including at least an accelerator opening and a vehicle speed, and an operating state of the internal combustion engine including at least an engine warm-up state, an engine speed, and an engine load;
b. Target driving force calculating means for calculating a target driving force to be output by the vehicle based on the detected accelerator opening and vehicle speed;
c. Output calculation means for calculating the output of the internal combustion engine and the gear ratio of the automatic transmission based on the calculated target driving force and the detected operating state;
d. Actuator control means for controlling an actuator for adjusting the output of the internal combustion engine based on the calculated output;
And e. Shift control means for controlling the automatic transmission based on the calculated gear ratio, and
f. High-load operation state detection means for detecting a high-load operation state of the internal combustion engine based on the detected operation state;
g. When the high-load operation state is continuously detected for a predetermined time or more, it is determined that the calculated gear ratio can not achieve the calculated target driving force, and the gear ratio can be achieved with the target driving force. Correction means to correct
A vehicle driving force control apparatus comprising: Said output calculation means, wherein when correcting the gear ratio, the vehicle driving force control apparatus according to claim 1, wherein said possible to perform the full-load enrichment avoidance operation to the internal combustion engine.

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