JPH06117285A - Travel control device for vehicle - Google Patents

Abstract

PURPOSE:To obtain always an almost constant feedback control characteristic in spite of a difference in engine rotating speed, throttle valve opening and speed change stage of an automatic transmission in a vehicle travel control device to carry out feedback control on the throttle valve opening so that actual vehicle speed becomes target vehicle speed. CONSTITUTION:The first correction factor f (NE) determined so that an almost same output torque change can be obtained in spite of fluctuation of engine rotating speed NE, the second correction factor f(theta) determined so that the almost same output torque change can be obtained in spite of the size of throttle valve opening (theta) and the third correcting factor f(s) determined so that an almost same driving force change can be obtained in spite of kinds of speed change stages of an automatic transmission, are found respectively in steps SH1, SH2 and SH3, and an adjusting quantity DELTATA of the trottle valve opening is calculated by feedback control by using these.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle travel control device, and more particularly to an improvement of a technique for feedback controlling a throttle valve opening in accordance with a deviation between a target vehicle speed and an actual vehicle speed.

[0002]

2. Description of the Related Art A throttle valve opening degree is set in accordance with a deviation of an actual vehicle speed to a predetermined target vehicle speed when a predetermined traveling control condition including at least an accelerator OFF state is satisfied. Feedback control is considered in automatic engine braking control and automatic cruise control in automatic vehicles. One example is the automatic engine braking control disclosed in Japanese Patent Application No. 4-46111 filed by the applicant earlier, and when the accelerator operation is released on a downhill or the like, the vehicle speed at the time of releasing the accelerator operation is set. As the target vehicle speed, the throttle valve opening is feedback-controlled while downshifting as necessary so that the actual vehicle speed becomes the target vehicle speed. In such feedback control,
Generally, the adjustment amount ΔTAb of the throttle valve opening is calculated according to a well-known feedback control formula by PID (proportional integral derivative) operation shown in the following formula (1), and the adjustment amount ΔTAb is calculated.
The throttle valve opening is changed only by TAb. F (SPD) of this feedback control equation (1) is the deviation between the target vehicle speed and the current vehicle speed, and is proportional to the constants A, L,
M and K are set to constant values in advance by experiments or the like so that optimum feedback control characteristics can be obtained.

[0003]

[Equation 1]

[0004]

By the way, when the throttle valve opening is feedback-controlled according to the deviation of the vehicle speed as described above, the engine rotation speed and the throttle valve opening,
Or, depending on the driving condition such as the gear position of the automatic transmission,
In some cases, uniform control cannot always be performed. Specifically, as is clear from an example of the engine output characteristic of FIG. 17, the engine output torque with respect to the change of the throttle valve opening of the same amount in the high engine speed region and in the low engine speed region is The amount of change in the vehicle speed is different, and accordingly, the amount of change in the driving force is also different. Therefore, even when the deviation f (SPD) is the same and the adjustment amount ΔTAb is substantially the same, the change in the vehicle speed varies. In addition, the amount of change in the engine output torque and the amount of change in the driving force with respect to the same amount of change in the throttle valve opening are different between the case where the throttle valve opening is large and the case where the throttle valve opening is small. Similarly, even when the deviation f (SPD) is the same and the adjustment amount ΔTAb is substantially the same, the vehicle speed change varies. Therefore, for example, the feedback control is performed so that the adjustment amount ΔTAb of the throttle valve opening is optimal in a region where the engine speed is high or the throttle valve opening is large, in other words, the optimal feedback control characteristic is obtained. When the proportional constant A etc. of the equation (1) is set,
In a region where the engine rotational speed is low or a region where the throttle valve opening is small, even if the adjustment amount ΔTAb is the same, the amount of change in the engine output torque and the driving force becomes too large, and the hunting of the vehicle speed increases and the control characteristics deteriorate. . On the contrary, if the proportional constant A or the like is set so that the optimum feedback control characteristic is obtained in the region where the engine speed is low or the throttle valve opening is small, the region where the engine speed is high or the throttle valve opening is set. In a large region of, the change amount of the engine output torque and the driving force becomes insufficient, and the responsiveness deteriorates.

Further, since the amount of change in the driving force with respect to the change in the engine output torque varies depending on the gear ratio of the automatic transmission, even if the engine output torque changes in accordance with the adjustment amount ΔTAb, the gear stage of the automatic transmission changes. The amount of change in driving force varies depending on the type. Therefore, for example, if the proportional constant A or the like is set so that the optimum control characteristic is obtained at the high speed stage where the gear ratio is small, the driving force change becomes excessive on the low speed stage side where the gear ratio is large, and the vehicle speed hunting is expanded. On the other hand, if the proportional constant A or the like is set so that the optimum control characteristic is obtained at the low speed stage having a large gear ratio, the change in the driving force becomes insufficient on the high speed stage side having a small gear ratio, and the responsiveness deteriorates.

The present invention has been made in view of the above circumstances, and an object thereof is to always obtain good feedback control characteristics irrespective of differences in vehicle running states such as engine speed. Especially.

[0007]

In order to achieve the above object, the adjustment amount of the throttle valve opening by the feedback control may be corrected based on the vehicle running state such as the engine rotation speed. As shown in the claim correspondence diagram of FIG. 1, when the predetermined traveling control condition including at least the accelerator being in the OFF state is satisfied, the actual vehicle speed becomes the predetermined target vehicle speed. In a vehicle travel control device including a throttle control unit that feedback-controls a throttle valve opening according to a deviation, an adjustment amount of the throttle valve opening obtained according to the deviation of the vehicle speed by the feedback control,
Correcting means is provided for correcting based on the running state of the vehicle including at least one of the gear ratio of the automatic transmission, the engine speed, and the throttle valve opening so that the driving force change corresponding to the deviation can be obtained. Is characterized by.

[0008]

In such a vehicle running control device, the adjustment amount of the throttle valve opening which is obtained by the feedback control in accordance with the deviation of the vehicle speed is changed by the correcting means so as to change the driving force corresponding to the deviation. As it is obtained, the feedback control characteristic is optimized in advance in a certain specific running state because it is corrected based on the running state of the vehicle including at least one of the gear ratio of the automatic transmission, the engine rotation speed, and the throttle valve opening. Even if the feedback control type is set so that the vehicle speed deviation is always dealt with by the correction means correcting the adjustment amount according to the traveling state in other traveling states where the engine rotation speed and the like are different. If the driving force change, that is, the vehicle speed deviation is the same, it is possible to obtain a substantially constant driving force change regardless of the difference in the running state. Now, so as to equal the feedback control characteristics and upon the particular running state feedback controlled is set is obtained. As a result, it is possible to prevent the feedback control characteristic from being varied due to the difference in the running state such as the engine rotation speed, and to prevent the vehicle speed hunting from increasing and the responsiveness from deteriorating.

The correction means preferably corrects the adjustment amount of the throttle valve opening based on all of the gear ratio of the automatic transmission, the engine speed, and the throttle valve opening. Even if the correction is performed based on the above, it is possible to obtain a temporary effect, and it is also possible to perform the correction in consideration of other traveling states such as atmospheric pressure. In addition, as a mode of correcting the adjustment amount, the adjustment amount calculated according to the feedback control formula may be corrected, or the proportional constant itself of the feedback control formula may be corrected.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings.

Referring to FIG. 2, in the combustion chamber 12 of the gasoline engine 10, an air cleaner 14, an air flow meter 16, an intake passage 18, a throttle valve 20, a bypass passage 22, a surge tank 24, an intake manifold 26,
And air is taken in through the intake valve 28,
Fuel gas injected from a fuel injection valve 30 provided in the intake manifold 26 is mixed with the air. The air flow meter 16 measures the intake air amount, and outputs a signal representing the intake air amount to the engine control computer 32. Throttle valve 20
Is for continuously changing the amount of air taken into the engine 10. The throttle valve opening θ is controlled according to the throttle control signal DTA supplied from the throttle control computer 35, and The valve 20 is provided with a throttle position sensor 36, and outputs a throttle valve opening signal Sθ representing the throttle valve opening θ to the engine control computer 32, the transmission control computer 34, and the throttle control computer 35. The throttle position sensor 36 has an idle switch function and outputs an idle signal indicating that the throttle valve 20 is fully closed to the computers 32, 34 and 35 together with the throttle valve opening signal Sθ. Bypass passage 2
2 is arranged in parallel with the throttle valve 20, and the idle speed control valve 3 is provided in its bypass passage 22.
8 is provided, and an engine control computer 32
By controlling the opening of the idle speed control valve 38, the amount of air that bypasses the throttle valve 20 is adjusted, and the engine speed during idling is controlled. The injection timing and the injection amount of the fuel injection valve 30 are also controlled by the engine control computer 32. An intake air temperature sensor 40 that measures the temperature of intake air is provided upstream of the air flow meter 16, and a signal representing the intake air temperature is sent to the engine control computer 32.
Output to.

The engine 10 includes an intake valve 28 and an exhaust valve 4
2, a piston 44, and an ignition plug 46. The ignition plug 46 generates an ignition spark by a high voltage supplied from an igniter 48 controlled by the engine control computer 32 through a distributor 50. , The crankshaft is rotated by exploding the mixed gas in the combustion chamber 12 and moving the piston 44 up and down. The intake valve 28 and the exhaust valve 42 are adapted to be opened and closed by a cam shaft which is rotationally driven in synchronization with the rotation of the crankshaft, and by a variable valve timing mechanism (not shown) controlled by the engine control computer 32. The opening / closing timing is adjusted by changing the rotational phases of the camshaft and the crankshaft. Then, the exhaust gas burned in the combustion chamber 12 is exhausted from the exhaust valve 42 to the exhaust manifold 5
4, the exhaust passage 56, and the catalyst device 58 to be discharged to the atmosphere. The engine 10 is provided with a water temperature sensor 60 for measuring the engine cooling water temperature, which outputs a signal representing the engine cooling water temperature to the engine control computer 32, and the exhaust manifold 5
4 is an oxygen sensor 62 for detecting the oxygen concentration in the exhaust gas.
Is provided and outputs a signal representing the oxygen concentration to the engine control computer 32. Further, the distributor 50 is provided with a rotation angle sensor 51 that generates a pulse in synchronization with the rotation of the crankshaft. The pulse signal, that is, the engine rotation speed signal SNE representing the engine rotation speed NE is sent to the engine control computer 32 and Output to the transmission control computer 34.

The engine control computer 32, the transmission control computer 34, and the throttle control computer 35 are all CPU, RAM, R.
The transmission control computer 34 is configured to include an OM, an input / output interface circuit, an A / D converter, and the like, and uses the temporary storage function of the RAM to perform signal processing in accordance with a program stored in advance in the ROM. In addition to the above signals, is a pattern signal SP indicating a selection pattern from the pattern select switch 70, a brake signal SB indicating that the brake is operated by the brake lamp switch 72, and an overdrive switch 74 to an O / D shift stage. O / indicating gear shift permission
A D signal SO and an accelerator operation amount signal SAc representing the operation amount Ac of the accelerator pedal are supplied from the accelerator operation amount sensor 76, respectively. The accelerator operation amount signal SAc is also supplied to the engine control computer 32 and the throttle control computer 35. The pattern select switch 70 has at least an automatic engine braking pattern for automatically increasing engine braking on a downhill road, etc., and also has a power pattern and fuel consumption for performing shift control of the automatic transmission 78 based on a shift map emphasizing power performance. This is for the driver to select a desired driving pattern from a plurality of predetermined driving patterns such as an economy pattern in which gear shift control is performed according to a priority shift map. Further, the brake lamp switch 72 is arranged in the vicinity of the brake pedal, and is turned on or off depending on whether or not the brake pedal is depressed.
It is composed of an ON-OFF switch or the like for switching F.

The automatic transmission 78 includes a torque converter 110, a first transmission 112, and a second transmission 114, as shown in FIG. 3, for example. The pump impeller of the torque converter 110 is connected to the crankshaft 118 of the engine 10, and the turbine impeller of the torque converter 110 is the input shaft 1.
It is connected to the carrier 122 of the first transmission 112 via 20. The first transmission 112 includes a sun gear 124, a ring gear 126, and a planetary gear device including a planetary gear 128 rotatably arranged on the carrier 122 and meshed with the sun gear 124 and the ring gear 126. 124 and carrier 1
22 and a clutch C ₀ and a one-way clutch F _0.
Are provided in parallel, and the sun gear 124 and the housing 130 are provided.
A brake B ₀ is provided between the and.

The second transmission 114 is rotatably disposed on the sun gear 132, the pair of ring gears 134 and 136, and the carrier 138 so as to be rotatable on the sun gear 132, the planetary gear 140 meshed with the ring gear 134, and the carrier 142. The planetary gear 1 arranged and meshed with the sun gear 132 and the ring gear 136.
44, and a clutch C ₁ is provided between the ring gear 136 and the ring gear 126 of the first transmission 112, and between the sun gear 132 and the ring gear 126. Clutch C
₂ is provided, a brake B ₁ is provided between the sun gear 132 and the housing 130, and a one-way clutch F ₁ and a brake B ₂ that are provided in series are provided in parallel, and the brake B ₁ is provided between the carrier 138 and the housing 130. The brake B ₃ and the one-way clutch F ₂ are provided in parallel with each other. Further, the ring gear 134 and the carrier 142 are the output shaft 1
46, and its output shaft 146 is connected to the drive wheels via a differential gear device or the like.

The clutches C _{0 to} C ₂ and the brake B
_{0 to} B ₃ (hereinafter, unless otherwise distinguished, the clutch C,
The brake B) is a hydraulic friction engagement device that is engagement-controlled by a hydraulic actuator such as a multi-plate clutch or band brake, and hydraulic oil is supplied from the hydraulic control circuit 150 to the hydraulic actuator. Has become. The hydraulic control circuit 150 is provided with a large number of switching valves and the like, and by switching the excitation and non-excitation of the solenoids S1, S2, and S3 in accordance with a signal from the transmission control computer 34, the hydraulic circuit is switched. The clutch C and the brake B are selectively engagement-controlled, and as shown in FIG. 4, any one of the four forward gears is established. In FIG. 4, the "○" mark in the solenoid column means excitation, and the "○" mark in the clutch and brake columns means engagement. Shift position "D", "S",
“L” is the operating range of the driver's shift lever,
In the "D (drive)" range, gear shift control is performed in four speeds from 1st to O / D, and in the "S (second)" range, gear shift control is performed in two speeds, 1st and 2nd.
In the (low) range, it is fixed to the 1st gear. The gear ratio (rotational speed of the input shaft 120 / rotational speed of the output shaft 146) is the largest at 1st, 2nd, 3rd, O / D.
It becomes smaller as becomes, and the gear ratio of 3rd is 1.0. Further, in the "D" range, the engine brake acts at 3rd and O / D, and the engine brake does not work at 1st and 2nd due to the action of the one-way clutches F ₂ and F ₁ , but they are shown in parentheses ( 1st),
At (2nd), the brakes B ₃ and B ₁ are engaged by exciting the solenoid S3, and the engine brake is activated. 2n of "S" range
The engine brake operates even at the first position in the d and "L" ranges. Although illustration is omitted,
When the shift lever is operated to the "R (reverse)" range, the manual shift valve of the hydraulic control circuit 150 is switched to establish the reverse shift speed.

The automatic transmission 78 is provided with a pair of rotation speed sensors 80 and 82. The rotation speed sensor 80 is the input shaft 120, that is, the torque converter 11.
The rotational speed sensor 82 detects the rotational speed N _T of the turbine impeller of 0, the rotational speed sensor 82 detects the rotational speed N _O of the output shaft 146, and the rotational speed signals representing the rotational speeds N _T and N _O , respectively. SN _T, and outputs the SN _O to the transmission control computer 34. Further, a neutral start switch 84 is provided in the hydraulic control circuit 150, and the "D", "S", from the position of the manual shift valve that is switched by operating the shift lever.
A shift range such as "L" or "R" is detected, and a shift range signal SR representing the shift range is output to the transmission control computer 34. The oil pressure control circuit 150 is also provided with an oil temperature sensor 86 for detecting the oil temperature (A / T oil temperature) THO of the hydraulic oil.
An oil temperature signal STHO indicating HO is output to the transmission control computer 34.

The control computers 32, 3 are
Necessary information is transmitted and received between Nos. 4 and 35, and the throttle valve opening signal Sθ, the engine speed signal SNE, and the accelerator operation amount signal SAc are at least one of the control computers 32, 34 ,. Alternatively, it may be supplied to 35. In addition, various other signals that represent the operating state of the vehicle, such as the steering angle of the steering wheel, the gradient of the road surface, and the exhaust temperature, can be captured and used for engine control, shift control of the automatic transmission 78, and throttle control. It is possible.

Then, the engine control computer 32 uses the intake air amount, the throttle valve opening θ, the engine rotational speed NE, the cooling water temperature of the engine 10, the intake air temperature, the oxygen concentration in the exhaust passage 56, and the accelerator operation. Quantity Ac
In accordance with the above, for example, the fuel injection valve 3 is based on a predetermined data map or an arithmetic expression so as to reduce fuel consumption and harmful exhaust gas while securing a required engine output.
It controls the injection amount and injection timing of the fuel gas by 0, the ignition timing by the igniter 48, the idle speed by the idle speed control valve 38, the opening and closing timing of the intake and exhaust valves 28, 42 by the variable valve timing mechanism, and the like. The transmission control computer 34 controls the throttle valve opening θ, the engine speed NE, the selection pattern represented by the pattern signal SP, the presence / absence of the brake operation represented by the brake signal SB, and the O / D shift stage represented by the O / D signal SO. Whether or not shifting is possible, accelerator operation amount Ac, automatic transmission 78
Of the solenoid S based on the output shaft rotation speed N _{O of the}
By switching the excitation and non-excitation of 1, S2, and S3, the shift stage of the automatic transmission 78 is switched and controlled. The transmission control computer 34 also switches the lockup clutch of the torque converter 110 between full engagement, a slip state, and release by duty-controlling a solenoid (not shown) provided in the hydraulic control circuit 150. In addition, the throttle valve opening θ of the throttle valve 20 is controlled according to the accelerator operation amount Ac, and when the accelerator operation amount Ac is zero, the throttle valve opening θ is adjusted to control the engine braking force. Therefore, the throttle command signal SQ is output to the throttle control computer 35. Throttle control computer 35
Is basically a throttle control signal D for controlling the throttle valve opening θ according to the throttle command signal SQ.
It is designed to output TA.

Hereinafter, the shift control and the throttle control by the transmission control computer 34 will be specifically described with reference to the flow charts of FIGS. The flowcharts of FIGS. 5 and 6 relate to the shift control for switching the shift stage of the automatic transmission 78, and the flowcharts of FIGS. 7 to 9 relate to the throttle control. The following control is performed when the "D (drive)" range in which gear shifting is performed in four forward gears is selected, and is repeatedly executed with a cycle time of about 8 to 32 msec.

After step S1 in FIG.
8 is a portion for performing a shift determination as to whether or not to switch the shift stage, and if step S40 is NO, that is, flag F3
Is not "1". The flag F3 is shown in FIG.
When all the conditions of steps SS1 to SS5 are satisfied and the automatic engine braking control is executed, it is set to “1” in step SS14 or SS19 of FIG. 8, and any one of the conditions of steps SS1 to SS5 is satisfied. If not, it is set to "0" in step SS6,
Steps S1 and subsequent steps are executed in the case of normal shift control in which automatic engine braking control is not performed.

In step S1, it is judged based on the O / D signal SO whether or not shifting to the O / D shift stage is possible, and the O / D signal SO is OFF, that is, the O / D shift stage is prohibited. If so, the current O /
It is determined whether or not it is the D shift stage. The current gear stage is determined by the output state of the excitation signal for exciting the solenoids S1, S2, S3. Where O now
The / D shift stage means that the overdrive switch 74 has been turned OFF while traveling at the O / D shift stage. In this case, the flag F2 is determined in step S14.
Is set to "1" and then "3rd" is set as the next gear in step S15. When the determination in step S1 is NO, that is, when the O / D gear is allowed, or even when the determination in step S1 is YES, the determination in step S2 is NO and the current 3rd is not the O / D gear.
Otherwise, if the determination in step S3 is no, then step S4 is executed. In step S4, it is determined whether or not the current shift speed is the O / D shift speed, and if it is not the O / D shift speed, it is determined whether or not upshift is performed by executing step S5 and the following steps. .

In step S5, a predetermined upshift map is searched to obtain the upshift vehicle speed Vu. As shown by the solid line in FIG. 10, the upshift map is predetermined for each type of shift based on the accelerator operation amount Ac and the vehicle speed V. The smaller the accelerator operation amount Ac is, the larger the vehicle speed V is. It is designed to be upshifted to the high speed side. Shift up vehicle speed Vu
It is determined according to the upshift map based on the accelerator operation amount Ac, at the next step S6, the current vehicle speed V and the shift-up vehicle speed Vu that corresponds to the output shaft rotational speed N _O of the rotational speed signal SN _O represents Compare
Determine whether to perform an upshift. That is, V ≦
If it is Vu, it is not necessary to perform an upshift, and it is determined in step S8 whether or not the current shift speed is 1st. However, if V> Vu, the flag F1 is set to "1" in step S7, and then, in step S15, the shift speed higher than the current shift speed is set as the next shift speed. In this case, even if the current gear stage is, for example, 2nd, the accelerator operation amount Ac sharply decreases after the gear shift determination to 3rd is made and before the gear stage is actually switched to 3rd. When the "3 → O / D" upshift line is exceeded, the O / D gear is set. In step S5, the shift-up vehicle speed Vu for all upshift lines is obtained from the current accelerator operation amount Ac, and in step S6, the respective shift-up vehicle speed Vu and the current vehicle speed V are compared to determine the upshift gear shift. Do it.

If the determination in step S3 is YES,
If the determination in step S4 is YES, or
If the result of the determination at 8 is NO, the process from step S10 is executed to determine whether to downshift. Step S
In step 10, a predetermined downshift map is searched to obtain the downshift vehicle speed Vd. As indicated by the broken line in FIG. 10, the downshift map is predetermined for each type of shift based on the accelerator operation amount Ac and the vehicle speed V, and as the accelerator operation amount Ac increases and the vehicle speed V decreases. It is designed to downshift to the lower speed side. The downshift vehicle speed Vd is the accelerator operation amount A.
It is determined according to the downshift map based on c, and in the next step S11, the current vehicle speed V corresponding to the output shaft rotation speed N _O is compared with the above-mentioned downshift vehicle speed Vd, and it is determined whether or not a downshift is performed. To do. That is,
If V> Vd, it is not necessary to perform a downshift, the flag F2 is set to "0" in step S13, and a series of shift determination is ended. However, if V≤Vd, step S13 is performed.
After setting the flag F2 to "1" in step 12, step S
In step 15, a shift speed lower than the current shift speed is set as the next shift speed. In this case, even if the current gear stage is, for example, O / D, the accelerator operation amount Ac increases sharply after the gear shift determination to 3rd is made and before the gear stage is actually switched to 3rd. It becomes "2 ← 3"
If the line exceeds the downshift line, the 2nd shift speed is set. At step S10, the current accelerator operation amount Ac
To downshift vehicle speed V for all downshift lines
d is obtained, and in step S11, the shift down vehicle speed Vd is compared with the current vehicle speed V to make a downshift shift determination.

If step S40 is YES, that is, if the automatic engine braking control is being executed, step S41 is executed after step S40,
It is determined whether the flag F5 is "0". The flag F5 is
When the automatic engine brake control is executed and all the conditions of steps SS1 to SS5 in FIG. 7 are satisfied and the brake pedal is depressed, the value is set to “1” in step SS23 in FIG. 8 and otherwise. It is set to "0" in step SS6 or SS12, and the flag F
If 5 = 0, step S42 is executed, and flag F5
When = 1, step S45 is executed. In step S45 executed when the brake pedal is depressed, a predetermined downshift map for engine braking is searched to obtain the downshift vehicle speed Ved for engine braking. The downshift map during engine braking is predetermined for each type of shift based on the accelerator operation amount Ac and the vehicle speed V, like the normal downshift map shown by the broken line in FIG. ,
It is easier to downshift because it deviates to the higher vehicle speed side than the normal downshift map. Downshift vehicle speed Ve
d is obtained according to the downshift map during engine braking based on the accelerator operation amount Ac, and in the next step S46, the current vehicle speed V corresponding to the output shaft rotation speed N _O and the downshift vehicle speed Ved are compared. Then, it is determined whether or not the downshift is performed. That is,
If V> Ved, it is not necessary to downshift, and the flag F2 is set to "0" in step S44 to complete the shift determination. However, if V≤Ved, step S4 is performed.
After setting the flag F2 to "1" in step 7, step S4
In step 8, a shift speed lower than the current shift speed is set as the next shift speed. The gears set here are those to which engine braking is applied, and the gears shown in parentheses in FIG. 4 are set in the 2nd or 1st. In this case, even if the current gear stage is, for example, O / D, the vehicle speed V decreases sharply after the gear shift determination to 3rd is made and before the gear shift to 3rd is actually performed. When the "2 ← 3" downshift line is exceeded, the 2nd shift speed is set. In step S45, the downshift vehicle speed Ved for all downshift lines is obtained from the current accelerator operation amount Ac, and in step S46, each downshift vehicle speed Ved is compared with the current vehicle speed V to make a downshift determination. Do it.

In step S42 executed when the brake pedal is not depressed, it is determined whether the flag F4 is "1". The flag F4 is set to "1" in step R11 of FIG. 9 when downshifting is performed to increase the engine braking force in the automatic engine braking control, and when the shift output of the downshift is performed, the flag F4 of FIG. It is set to "0" in step S31, and F4 = 0
If so, the flag F2 is set to "0" in step S44 to terminate the shift determination, and if F4 = 1, step S4
Execute 3. In step S43, the next low speed stage where the engine brake acts as the next shift stage, that is, 2nd
Alternatively, in the case of 1st, the gear stage shown in parentheses in FIG. 4 is set.

When the next shift speed is set in step S15, S43, or S48, the shift timing time T1 is set in step S16.
This gear shift timing time T1 is a delay time until the gear shift is actually output after the gear shift judgment is made (step S30), and a plurality of gear shifts are performed in a short time (multiple gear shift). ) And when the accelerator pedal is quickly released to activate the engine braking on a downhill, even if an upshift determination to the O / D gear is made, before the actual upshift is performed. This is provided to prohibit upshifting to the O / D gear when the accelerator operation amount Ac becomes substantially zero.
A fixed value may be set in advance, but different times may be set depending on the type of shift such as upshift or downshift, or downshift in automatic engine braking control. Further, it may be set by a map, a calculation formula, or the like according to the accelerator operation amount Ac at the time of shift determination, the vehicle speed V, the gear stage, and the like.

Next, the flow chart of FIG. 6 for actually changing the shift speed will be described. FIG. 6 is a portion for executing an upshift and a downshift for increasing the engine braking force in accordance with the shift determination of FIG. 5. In step S20, whether the flag F1 is "1", that is, the upshift shift determination is performed. Determine whether or not If the flag F1 is "1", steps S21 and subsequent steps are executed, but if not, step S33 is executed. In step S33, it is determined whether or not the flag F4 is "1", that is, whether or not the downshift is for increasing the engine braking force. If the flag F4 is "1", the steps from step S21 are executed. If not, step S32 is immediately executed, the timer Ta is reset, and the process ends.

In step S21, the shift range signal SR
Is determined to be "D (drive)", and in step S22, the traveling pattern represented by the pattern signal SP is "automatic engine braking pattern".
Determining whether a determines whether larger than the lower limit vehicle speed V1 of the vehicle speed V is preset to correspond to the output shaft rotation speed N _O representing the rotational speed signal SN _O In step S23, in step S24 It is determined whether or not the vehicle speed V is equal to or lower than a predetermined upper limit vehicle speed V2. In step S25, the accelerator is turned off, that is, whether or not the accelerator operation amount Ac represented by the accelerator operation amount signal SAc is substantially zero. In consideration of the above, it is determined whether or not it is about 1.5% or less. In step S26, it is determined whether or not the next gear set in step S15 is an O / D gear. Lower limit vehicle speed V
1 and the upper limit vehicle speed V2 define a vehicle speed range in which special control for engine braking is performed.
Is set to, for example, about 20 km / h, and the upper limit vehicle speed V2 is set to, for example, about 110 km / h. If even one of the steps S21 to S26 is NO, in step S28, the change in the next shift stage set in step S15 is not changed in step S27, but the determination in steps S21 to S26 is made. In the case of all YES, the next gear is set to "3r" in step S27.
Change to "d". In step S26, it is determined whether or not the next shift speed set in step S15 is O / D. In step S27, the next shift speed is changed from O / D to 3r.
Even in the cycle after the change to d, the determination in step S26 is YES.

In step S29, it is determined whether or not the content measured by the timer Ta is not less than the shift timing time T1. The above steps S20 and thereafter are repeated until the shift timing time T1 is reached, but when the shift timing time T1 is reached, step S30 is executed and the solenoid S1,
The excitation and non-excitation of S2 and S3 are switched to switch the shift stage of the automatic transmission 78 to the next shift stage set in step S15 or S43 or the 3rd shift stage changed in step S27. After that, the flag F1 is set to "0" and the flag F4 is set to "0" in step S31, and the timer Ta is reset in step S32. The timer Ta has elapsed after the upshift determination was made and the flag F1 was set to "1", or the downshift determination for increasing the engine braking force was made and the flag F4 was set to "1". It measures time.

Here, in step S6, O / D
Even if an upshift determination to the shift stage is made, step S
Until the gear is actually changed at 30
That is, the shift timing time T after the shift determination is made.
If all of the conditions of steps S21 to S26 including the accelerator OFF are satisfied before the lapse of 1, the next shift speed is changed to 3rd, and thus further speedup is disliked on a downhill or the like. When the driver releases the accelerator by the driver, the actual shift to the O / D shift stage is prevented even if the upshift shift determination is made as the accelerator operation amount Ac decreases, and the O / D shift stage is prevented. The reduction in engine braking force due to gear shift to is favorably avoided. For example, when the driver releases the accelerator in the case of traveling for the second time at the state of point A in FIG. 10, “2
Since the accelerator operation amount Ac becomes zero across the "3" upshift line and the "3 → O / D" upshift line, a final shift determination from 2nd to O / D is made in step S6. , In step S15, the O / D shift stage is set as the next shift stage, but if the accelerator operation amount Ac becomes zero before the shift timing time T1 elapses after the "2 → 3" upshift determination is made, "3 → O /
Even if the next shift speed is changed to O / D by crossing the "D" upshift line, the next shift speed is changed to 3rd in step S27, and therefore the upshift to the O / D shift speed is not performed.

Even if the accelerator is turned off once,
If the pedal is depressed again before reaching the shift timing time T1, the determination in step S25 is NO, and in step S28 the next shift stage is set to the O / D set in step S15. When the pedal is depressed, the driver does not need the engine braking force so much, and therefore the driver may upshift to the O / D gear. Even if the determination of step S29 is inserted between steps S20 and S21, the determination of step S21 and subsequent steps is executed based on the operating state when the shift timing time T1 has elapsed, and the shift speed is switched. good.

Further, the accelerator return speed is relatively slow,
Even if the accelerator is not turned off within the shift timing time T1, the shift as set in step S15 is executed, but in this case as well, it is considered that the driver does not need much engine braking force, so O / There is no problem in upshifting to the D gear. In other words,
If the driver needs the engine braking force, he / she should release the accelerator pedal quickly, and if he / she wants to coast or the like, which does not require much engine braking force, he / she should release the accelerator pedal slowly. It's good.

Next, the throttle control of FIGS. 7 to 9 will be described. First, in steps SS1 to SS5 of FIG. 7, the same as steps S21 to S25 regarding the shift range, the traveling pattern, the vehicle speed V, and the accelerator operation amount Ac. If the judgment is made and all the conditions are satisfied, the automatic engine braking control of step SS8 and thereafter is executed. In this embodiment, these steps SS1 to SS5 correspond to the predetermined traveling control conditions. And those steps SS
If any one of the determinations 1 to SS5 is NO, the flag F3, the flag F5,
And flag F7 are set to "0", respectively, and step SS
At 7, normal throttle control is performed. Step SS
The normal throttle control of 7 is the accelerator operation amount signal SA
Based on the accelerator operation amount Ac represented by c, the throttle valve opening TA (A
c) the determined, and sets the throttle opening TA (Ac) to the target throttle valve opening degree TA ^*, the throttle command signal SQ indicating the target throttle valve opening TA ^*
Is output to the throttle control computer 35. The throttle control computer 35 uses the feedback control or the like to determine the actual throttle valve opening θ of the throttle valve 20.
The throttle control signal DTA is output to the throttle valve 20 so as to match the target throttle valve opening TA ^* represented by the throttle command signal SQ, that is, TA (Ac).

In step SS8, which is executed when all the conditions in steps SS1 to SS5 are satisfied, the flag F
It is determined whether or not 3 is "1", but this flag F3
Is set to "0" in step SS6, so it is "0" when step SS8 is first executed,
Then, step SS10 is executed to set the vehicle speed V at that time to the target vehicle speed Vm. The flag F3 is set to "1" in step SS14 or SS19 of FIG.
In the subsequent cycles, the determination in step SS8 is YES and step SS9 is executed. In step SS9,
The vehicle speed (Vm-Vf) obtained by subtracting a predetermined constant value Vf from the target vehicle speed Vm and the vehicle speed V at that time are compared to obtain V
If (Vm-Vf), step SS11 and subsequent steps in FIG. 8 are executed, but if V≤ (Vm-Vf), step SS10 is executed again, and after changing the target vehicle speed Vm to the vehicle speed V at that time, step Execute SS11 and below. Considering the fluctuation of the vehicle speed V due to the feedback control of the throttle valve opening θ in steps R4 and R6 of FIG. 9, the constant value Vf is determined to be NO in step SS9 depending on the fluctuation of the vehicle speed V accompanying the throttle control. Although it does not occur, it is determined that the target vehicle speed Vm is changed in step SS10 if the judgment of step SS9 is NO when the vehicle speed V is relatively greatly lowered by the depression operation of the brake.

In step SS11 of FIG. 8, it is judged whether or not the brake pedal is depressed based on the brake signal SB. If the brake is OFF, that is, if the pedal is not depressed, step SS12 and the following steps are executed. When the person desires further deceleration and depresses the brake, the determination in step SS11 becomes NO, and steps SS22 and SS23 are executed. Step SS2
In No. 2, in order to increase the engine braking force, the target throttle valve opening TA ^{* is set} to 0, and the throttle command signal SQ representing the target throttle valve opening TA ^* is output to the throttle control computer 35, whereby the throttle valve is opened. 20 is fully closed. Further, in step SS23, the flag F5 is set to "1" so that steps S45 and below in FIG. 5 are executed. At the beginning of the automatic engine braking control, that is, in the first cycle in which the accelerator is turned off, the normal brake is turned off.
The judgment of 1 is YES and the step SS14 or SS
In FIG. 19, the flag F3 is set to "1", and in FIG. 5, the steps from step S41 onward during engine braking are executed.

Step SS executed when the brake is OFF
In step 12, the flag F5 is set to "0", and in step SS13, whether or not the flag F1 is "1", that is, the step S
At step 6, it is determined whether or not the upshift is determined. When the flag F1 = 1, the flag F3 is set to "1" in step SS14, and then the normal throttle control similar to that in step SS7 is performed in step SS15. If the upshift gearshift determination is not made, or if the upshift gearshift output is made and the flag F1 is set to "0" in step S31 of FIG. 6, the determination in step SS13 is NO. Then, in step SS16, it is determined whether the flag F6 is "0". The flag F6 is set to "1" in step R11 of FIG. 9 when the downshift is performed to increase the engine braking force. When the flag F6 = 0,
In step SS17, it is determined whether the flag F3 is already "1".

When the flag F3 is not "1" in the first cycle of the automatic engine braking control and the determination in step SS17 is NO, step SS20 is executed after setting the flag F3 to "1" in step SS19. The same normal throttle control as in step SS7 is performed.
When the flag F3 = 1, it is determined in step SS18 whether gear shifting is in progress, for example, whether or not the following expression (2) is satisfied. That is, in step S30 of FIG. 6, the gear shift output is performed and the solenoids S1, S
When the excitation and non-excitation of S2 and S3 are switched, the clutch C and the brake B of the automatic transmission 78 start to slip, and the rotation speed ratio of the turbine rotation speed N _T and the output shaft rotation speed N _O is changed, that is, Since the gear shift ends when the gear ratio i of the current gear stage after the gear shift output substantially matches, the rotational speeds N _T , N _O and the gear ratio i of the current gear stage i.
If the following equation (2) is satisfied, the gear shift is not being performed, and if the following equation (2) is not satisfied, the gear shift is being performed. Then, if the determination in step SS18 is YES, that is, if the shift is not in progress, the automatic engine brake throttle processing routine in step SS21 is executed, but if the shift is in progress, step SS20 is executed. The above equation (2) is set so as to be satisfied with a predetermined width in consideration of detection errors of the rotation speeds N _T and N _O. Also, during downshifts to increase engine braking power,
Since step SS24 and the subsequent steps are executed after step SS16, it is determined in step SS18 whether or not the shift is being substantially performed during the upshift.

[0039]

(2) N _T ≈N _O × i (2)

The automatic engine brake throttle processing routine of step SS21 is to feedback control the throttle valve opening θ so that the actual vehicle speed V substantially matches the target vehicle speed Vm set in step SS10 of FIG. Specifically, it is executed according to the flowchart of FIG. In step R1 of FIG. 9, it is determined whether the throttle valve opening θ is smaller than a predetermined determination value θ1. The determination value θ1 is a small value of about 1.5% or less, and is determined by an idle signal indicating that the throttle valve 20 is substantially fully closed. If θ ≧ θ1, that is, if the engine braking force can be increased by closing the throttle valve 20, the timer Tc is reset in step R2 and step R3 is performed.
Then, the flag F7 is set to "1", and then step R4 is executed. In step R4, the throttle valve opening TA1 (%) for making the vehicle speed V substantially match the target vehicle speed Vm is calculated according to the calculation formula of the feedback control according to the deviation between the target vehicle speed Vm and the current vehicle speed V.

The throttle valve opening TA1 is obtained by adding the adjustment amount ΔTA to the target throttle valve opening TA ^* at the present or previous cycle, as shown in the following equation (3), and the adjustment amount ΔTA Is calculated in accordance with the feedback control equation based on the PID (proportional integral derivative) operation shown in the following equation (4).

[0042]

[Equation 3] TA1 = TA ^* + ΔTA (3)

[0043]

[Equation 4]

The first to third terms in the braces of the equation (4) are the proportional operation term, the derivative operation term, and the integral operation term, respectively, and f (SPD) in each term is the target vehicle speed Vm.
Is a deviation (Vm-V) obtained by subtracting the current vehicle speed V from. The proportional constants L, M, K and the proportional constant B of each term are the most when the engine speed NE is in the high speed region, the throttle valve opening TA is substantially the maximum opening, and the gear stage is O / D. In order to obtain suitable feedback control characteristics,
A fixed value that is obtained in advance by experiments or the like is set.
Further, f (A) is a correction coefficient by which the proportional constant B is multiplied, and in the present embodiment, the feedback control is always suitable regardless of the level of the engine speed NE, the size of the throttle valve opening θ, and the type of gear. Therefore, it is calculated according to the engine rotational speed NE, the throttle valve opening θ, and the type of gear, for example, according to the flowchart of FIG. 11.

At step SH1 of FIG. 11, for example, as shown in FIG.
The first correction coefficient f (NE) is calculated from the predetermined data map shown in 2 based on the engine speed NE. The first correction coefficient f (NE) depends on whether the engine speed NE is high or low because the amount of change in the engine output torque and the amount of driving force with respect to the change in the throttle valve opening θ differ depending on the level of the engine speed NE. The purpose is to obtain a substantially constant feedback control characteristic.
In the graph of FIG. 12, based on the engine output characteristic as shown in FIG. 17, the throttle change amount with which the same degree of engine output torque change is obtained, the proportional constants B and the like of the feedback control equation (4) are set. The maximum rotation speed NEmax, which was the basis for the calculation, was calculated as 1.0. From the maximum rotation speed NEmax, the engine rotation speed N
The first correction coefficient f (NE) becomes smaller as E becomes lower, and becomes the minimum at the idle rotation speed NEidl. That is, the engine 10 of the present embodiment has the engine rotation speed NE.
The smaller is, the smaller the change in the throttle valve opening is, and the larger the output torque is changed.

In the subsequent step SH2, the second correction coefficient f (θ) is calculated based on the throttle valve opening θ from a predetermined data map shown in FIG. 13, for example. The second correction coefficient f (θ) varies depending on the magnitude of the throttle valve opening θ, because the engine output torque and the amount of change in the driving force with respect to the change in the throttle valve opening θ vary. This is to obtain a substantially constant feedback control characteristic regardless of the size. In the graph of FIG. 13, based on the engine output characteristic as shown in FIG. 17, the throttle change amount with which a similar engine output torque change can be obtained is set by each proportional constant B of the feedback control equation (4). The maximum opening θmax, which is the basis for the case, is calculated as 1.0. The second correction coefficient f (θ) becomes smaller as the throttle valve opening θ becomes smaller from the maximum opening θmax. That is,
In the engine 10 of the present embodiment, the smaller the throttle valve opening θ is, the larger the change in the output torque occurs with the smaller change in the throttle valve opening.

Further, in the next step SH3, the third correction coefficient f (S) is obtained from the predetermined data map shown in FIG. 14 based on the current shift speed. The third correction coefficient f (S) is different in the amount of change in the driving force with respect to the change in the throttle valve opening θ, that is, the change in the output torque of the engine 10, depending on the type of the shift stage of the automatic transmission 78.
The purpose is to obtain a substantially constant feedback control characteristic regardless of the type of gear. The data map of FIG. 14 shows the case of the O / D gear stage which is the basis for setting each proportional constant B and the like of the feedback control equation (4) such that the throttle change amount with which the same degree of driving force change is obtained. the present invention was determined as 1.0, based on the gear ratio i _1, 2nd shift stage gear ratio i _2, 3rd shift stage gear ratio i _3, O / D gear speed ratio i ₄ of the 1st shift stage It is set for each gear, and the third correction coefficient f (S) is closer to the lower gear.
Becomes smaller. That is, as the gear ratio is larger,
A large change in the driving force occurs with a small change in the throttle valve opening.

Then, in the subsequent step SH4, the correction coefficient f (A) is calculated by integrating all of the above f (NE), f (θ) and f (S), and in step SH5 the current vehicle speed with respect to the target vehicle speed Vm. The deviation f (SPD) of V = (Vm-V) is calculated. Further, in step SH6, the adjustment amount ΔTA is obtained from the equation (4), and in step SH7 the throttle valve opening degree TA1 is calculated.

Returning to FIG. 9, in the next step R5, based on the current gear position and the target vehicle speed Vm, the throttle valve opening degree that can maintain the target vehicle speed Vm when traveling on a flat surface,
That is, the throttle valve opening degree TAm (%) at which the driving force in consideration of the running resistance becomes zero is calculated by map interpolation from a prestored data map as shown in FIG. It is determined whether TA1 is smaller than the throttle valve opening TAm. FIG. 15 above
The data map of No. 2 is obtained by obtaining the throttle valve opening degree at which the driving force matches the running resistance for each shift speed and vehicle speed, based on the data as shown in FIG. 16 obtained experimentally in advance. In the data of FIG. 16, for example, in a vehicle equipped with an engine having the output characteristics shown in FIG. 17, the gear stage of the automatic transmission 78 is O / D (total gear ratio = 2.89).
05), the gear transmission efficiency is 0.855 and the tire effective radius is 0.306 m, for example, the vehicle speed is 80 km /
The throttle valve opening degree TAm (%) in the case of h is about 7.4 degrees for the throttle valve opening degree (angle) at the point B which coincides with the running resistance on the flat ground. And converted into%, (7.4 / 80) × 100 = 9.
It becomes 3. That is, in the data map of FIG.
The throttle valve opening TA ₄₅ when the vehicle speed is 80 km / h at the O / D gear is specifically 9.3%, and thus the throttle valve opening T at each vehicle speed at the O / D gear is T.
A _{41 to} TA ₄₇ are required. Regarding the 3rd speed and the 2nd speed and the 1st speed where the engine brake acts, the throttle valve opening TA _{31 to} TA ₃₇ , TA _{21 to} TA ₂₇ , TA ₁₁ is the same as the case of the O / D speed.
~ TA ₁₇ is required. This throttle valve opening TA
As is clear from the data in FIG. 16, m increases as the vehicle speed increases, and if the vehicle speed is the same, m increases as the gear shift ratio decreases and the gear shift ratio increases.

If TA1 <TAm, the throttle valve opening degree TA1 is set to the target throttle valve opening degree TA ^* in step R6, and the target throttle valve opening degree T is set.
By outputting the throttle command signal SQ representing A ^* to the throttle control computer 35, the actual throttle valve opening θ of the throttle valve 20 is changed to the throttle valve opening T.
It is controlled to be A1. These steps R4, R
By repeatedly executing 5 and R6, the throttle valve opening θ is rapidly controlled so that the vehicle speed V substantially matches the target vehicle speed Vm, and the target vehicle speed Vm when the accelerator is off or the vehicle speed V decreases due to the brake depression operation. Accordingly, the engine braking force with which the vehicle travels at the target vehicle speed Vm changed is obtained. In this embodiment, the vehicle speed V is set to the target vehicle speed Vm.
Since the throttle valve opening θ is feedback-controlled so as to substantially match with the vehicle speed V
The engine braking force is increased / decreased to substantially match the target vehicle speed Vm, and when the gradient changes from a steep gradient to a gentle gradient, it is prevented that the vehicle speed V is lowered against the driver's will due to excessive engine braking. It

Meanwhile, the determination in step R5 in the case of TA1 ≧ TAM sets NO, a throttle valve opening TAM in step R7 to the target throttle valve opening degree TA ^*, representing the target throttle valve opening TA ^* By outputting the throttle command signal SQ to the throttle control computer 35, the actual throttle valve opening θ of the throttle valve 20 is controlled to be the throttle valve opening TAm. This is because the engine braking force is increased / decreased so that the vehicle speed V substantially matches the target vehicle speed Vm regardless of the change in the road surface slope as described above, and therefore the throttle valve opening θ Is opened and the vehicle speed V is maintained at the target vehicle speed Vm. However, with such engine brake control, the driver usually thinks that the vehicle speed V decreases on an uphill road, and when driving on a flat ground. If so, the throttle valve opening TAm that can maintain the target vehicle speed Vm is set as the upper limit of the throttle valve opening TA1 by the feedback control. As a result, the target vehicle speed Vm is maintained on the downhill and the flat ground, but the vehicle speed V becomes lower than the target vehicle speed Vm according to the gradient on the uphill, and the traveling control as intended by the driver is performed. Become so.

When the throttle valve 20 is substantially fully closed and the engine braking force cannot be increased by the throttle control, the determination in step R1 is YES, step R8 is executed, and the flag F7 is "1". Determine if there is. When the flag F7 is not "1",
That is, when step R8 is executed after step R1 in the first cycle in which the accelerator is in the OFF state, steps R2 and thereafter are executed to reset the timer Tc and set the flag F7 to "1". Further, in the next step R9, it is determined whether or not the time content of the timer Tc, that is, the elapsed time after the throttle valve 20 is substantially fully closed exceeds a predetermined delay time T3. At the delay time T3, sufficient engine braking force cannot be obtained even when the throttle valve 20 is substantially fully closed.
~ It is for judging whether or not the throttle valve 20 is maintained in the fully closed state by the feedback control by R6, and a constant value may be set in advance, but the kind of shift and the vehicle speed V are used as parameters. It may be set by a data map or fuzzy inference. And T
If c <T3, the above steps R3 and below are executed,
If Tc ≧ T3, then in step R10,
It is determined whether or not the current gear is the lowest gear that can obtain the engine braking action, that is, the 1st gear in which the solenoid S3 is excited in this embodiment.
In the case of the shift stage, downshift cannot be performed, and therefore, the execution of step R3 and thereafter is repeated. When the shift speed is other than 1st, step R11 and thereafter are executed, the flag F4 instructing the downshift in order to increase the engine braking force is set to "1", and the flag indicating the throttle control at the time of the downshift. F6 is set to "1". When the flag F4 is set to "1", step S43 in FIG. 5 is executed, and when the flag F6 is set to "1", step SS24 in FIG.
The following will be executed.

In the next step R12, the throttle valve opening degree TA2 (%) at which substantially the same driving force is obtained before and after the downshift is calculated based on the type of the downshift and the current vehicle speed V, for example. It is calculated by map interpolation from a predetermined data map as shown in 18. The data map of FIG. 18 is based on the driving force data shown in FIG. 16 that has been experimentally obtained in advance, and the throttle valve 20 at the gear position before the downshift is used.
Is the same as or slightly smaller than the driving force when it is fully closed (acting as a braking force in this case), in other words, the driving force that makes the engine braking force the same or slightly larger, is obtained even after the downshift. Valve opening TA2
(%) Is calculated for each type of shift and vehicle speed. For example, when the vehicle speed is 80 km / h at the O / D gear and the accelerator is OFF, the driving force is about −300 N as indicated by point C in FIG. 16, so the O / D gear is shifted to the 3rd gear. 3 if shifted
In the data corresponding to FIG. 16 in the case of rd, the vehicle speed is 8
The throttle valve opening degree TA2 is a value of the throttle valve opening degree at which the above-mentioned driving force at 0 km / h, that is, a driving force equal to or slightly smaller than −300 N is obtained. 18 "O / D → 3r
d ”The throttle valve opening TA2 _{31 to} TA2 _3n during gear shifting is
In this way, the vehicle speed is determined for each of V _{1 to} V _n ,
"3rd → 2nd (S3ON)" Throttle valve opening TA2 _{21 to} TA2 _2n at the time of shifting, and "2nd → 1st (S3ON)
ON) ”Throttle valve opening during gear shifting TA2 _{11 to} TA2 _1n
Also, it is determined in the same manner as above by using the driving force data of the second shift speed and the first shift speed. The throttle valve opening TA2 increases as the vehicle speed increases for the same type of gear shift, and for the same vehicle speed, the throttle valve opening TA2 is larger in the downshift on the low speed side than in the downshift on the high speed side.

Further, in the subsequent step R13, the change timing time T2 of the throttle valve opening θ is set. The throttle valve opening change timing time T2 is a delay time from when the downshift gear shift output is performed in step S30 until the throttle valve 20 is opened and controlled, and is on the high speed stage side that is released during the downshift. The engine rotational speed NE and the A / T oil temperature THO were set as parameters in advance so as to increase the engine rotational speed NE in accordance with the timing at which the clutch C and the brake B started to slip. It is calculated by map interpolation from the data map of FIG. In this case, the higher the A / T oil temperature THO, the lower the viscous resistance of the hydraulic oil, the shorter the time required for draining and supply, and the faster the gear C is output to the clutch C and the brake B on the high speed stage side. Since the delay time until the start of slippage becomes shorter, the throttle valve opening change timing time T2 becomes smaller as the A / T oil temperature THO becomes higher. Further, as the engine speed NE is higher, the delay time until the engine 10 is actually blown up after the throttle valve 20 is opened is controlled. Therefore, the throttle valve opening change timing time T2 is higher as the engine speed NE is higher. It will be a small value.

When the flag F6 is set to "1" in step R11, in the subsequent cycles, step SS in FIG.
The determination of 16 is NO, and step SS24 is executed. In step SS24, it is determined whether or not the shift output for the downshift is performed in step S30 and the flag F4 is set to "0" in the next step S31. Until F4 = 0, the timer is set in step SS25. When Tb is reset and F4 = 0, steps SS26 and thereafter are executed. By resetting the timer Tb in step SS25, the timer Tb measures the elapsed time when the flag F4 is set to "0", in other words, when the downshift gearshift output is made, At step SS26, the timer T
It is determined whether or not the timing content of b is equal to or longer than the throttle valve opening change timing time T2. When the content measured by the timer Tb reaches the change timing time T2,
In step SS27 by setting the throttle valve opening TA2 to the target throttle valve opening degree TA ^*, and outputs a throttle command signal SQ indicating the target throttle valve opening TA ^* to the throttle control computer 35, the throttle valve 20 The actual throttle valve opening θ is controlled so as to become the throttle valve opening TA2. Further, in the next step SS28, the gear ratio i and the rotational speeds N _T and N of the current gear stage after the downshift gear shift output is performed.
Based on _O , it is determined from the above equation (2) whether or not the shift is completed. When the shift is completed, the flag F6 is set to "0" in step SS29. As a result, in subsequent cycles, step SS16 and subsequent steps are executed after step SS16.

Here, in the automatic engine braking control of the present embodiment, when the throttle valve 20 is feedback-controlled in steps R4 to R6 so that the vehicle speed V matches the target vehicle speed Vm, the deviation f (SPD of the vehicle speed ), The adjustment amount ΔTA calculated according to the feedback control equation (4) is approximately the same as the driving force change regardless of the level of the engine speed NE, the throttle valve opening θ, and the type of gear. The correction coefficient f obtained so that
Since it is corrected by (A), the driving force change always corresponds to the deviation f (SPD), that is, if the deviation f (SPD) is the same, regardless of the difference in the engine rotational speed NE, etc. Change is obtained. As a result, the feedback control characteristic equivalent to that in the traveling state in which the optimum feedback control characteristic in which the proportional constant B or the like of the control equation (4) is set can be obtained regardless of the difference in the engine rotation speed NE and the like. Like

In the present embodiment, of the series of signal processing by the transmission control computer 34, the part that executes steps R4 and R6 constitutes the throttle control means together with the throttle control computer 35, and steps SH1 to SH6. The part that executes is equivalent to the correction means.

Although one embodiment of the present invention has been described in detail with reference to the drawings, the present invention can be implemented in other modes.

For example, in the above-described embodiment, the correction coefficient f (A) is calculated based on the engine speed NE, the throttle valve opening θ, and the type of gear, but the engine speed NE, the throttle valve, etc. The effect of the present invention can be obtained by using only one or two of the opening degree θ and the type of shift speed. Other than that, it is also possible to calculate the correction coefficient f (A) in consideration of other traveling states such as atmospheric pressure.

In the above embodiment, the first to third correction coefficients are all less than or equal to 1 and are multiplied to calculate the correction coefficient f (A). However, the first to third correction coefficients are calculated. The data map for calculating the coefficient differs depending on the setting conditions when setting the proportional constant B etc. of the feedback control equation (4), and other calculation methods such as fuzzy inference when calculating the correction coefficient f (A) are used. It is also possible to use.

Further, although the correction coefficient f (A) is incorporated in the feedback control equation (4) in the above embodiment, after the adjustment amount ΔTAb is calculated according to the above equation (1), the correction coefficient f (A) is added to the adjustment amount ΔTAb. There is no problem even if it is corrected by multiplying f (A). It is also possible to correct by adding or subtracting a predetermined correction value obtained according to the engine rotation speed NE or the like to the adjustment amount ΔTAb.

Further, in the above embodiment, the throttle valve opening θ is feedback-controlled by the PID operation, but the feedback control can be performed by other operations such as PI operation and PD operation.

Further, in the above embodiment, the vehicle speed V when the accelerator is off or when the brake is released is set to be the target vehicle speed Vm as it is, but the target vehicle speed Vm does not have to completely match the vehicle speed V. Alternatively, the target vehicle speed Vm may be set by adding or subtracting a predetermined value to or from the vehicle speed V in consideration of a measurement error or the like.

Further, in the above embodiment, every time the determination at step SS9 becomes NO as the vehicle speed V decreases, step SS is performed.
10 was executed and the target vehicle speed Vm was sequentially changed according to the vehicle speed V at that time.
It does not matter if S9 is omitted and the target vehicle speed Vm is changed by the vehicle speed V when the brake is released, or the target vehicle speed Vm is sequentially updated based on the vehicle speed V when the brake is ON.

Further, in the above embodiment, the throttle valve opening θ
Has described the vehicle which is always controlled by the throttle control computer 35. However, in the vehicle in which the throttle valve 20 is mechanically connected to the accelerator pedal to be opened / closed, and the throttle valve 20 is automatically opened / closed when the accelerator is off. The present invention is also applicable. The configuration of the automatic transmission 78 and the number of gears can be changed as appropriate.

In the above embodiment, steps SS1 to S
When all the conditions of S5 are satisfied, the automatic engine braking control of step SS8 and subsequent steps is executed, but other conditions may be appropriately changed as long as it includes at least step SS5 for judging the accelerator OFF, such as power pattern and the like. It is also possible to perform the automatic engine braking control when the traveling pattern is selected, or to execute the automatic engine braking control regardless of the type of the traveling pattern. It is also possible to dispose the engine brake control switch independently of the pattern select switch 70.

Further, in the above embodiment, the vehicle speed limitation of steps SS3 and SS4 is provided as a condition for performing the automatic engine braking control. However, such vehicle speed limitation is not always necessary, and the vehicle speed limitation range is appropriately determined. Other conditions may be added as conditions for performing automatic engine braking control.

In the above embodiment, the case where the present invention is applied to the automatic engine braking control has been described.
The present invention can also be applied to automatic cruise control in which constant speed traveling is performed at a predetermined vehicle speed. The contents of the automatic engine braking control can be changed as needed.

Further, although the engine control computer 32, the transmission control computer 34, and the throttle control computer 35 are separately configured in the above embodiment, they may be configured by a single computer. It is possible.

Although not illustrated one by one, the present invention can be carried out in various modified and improved modes based on the knowledge of those skilled in the art.

[Brief description of drawings]

FIG. 1 is a diagram corresponding to a claim of the present invention.

FIG. 2 is a diagram illustrating a configuration of an automatic transmission and an engine portion of a vehicle including a vehicle travel control device that is an embodiment of the present invention.

FIG. 3 is a diagram illustrating a configuration of the automatic transmission of FIG.

FIG. 4 is a diagram showing a shift stage of the automatic transmission of FIG. 3, excitation of a solenoid for establishing the shift stage, and engagement operation of a clutch and a brake.

FIG. 5 is a flowchart illustrating an operation of determining whether to change a shift speed of the automatic transmission shown in FIG.

FIG. 6 is a flowchart illustrating an operation of shift control for switching a shift stage of the automatic transmission of FIG.

7 is a flowchart illustrating an operation of controlling the throttle valve opening of the engine of FIG. 2 together with FIG.

8 is a flowchart illustrating an operation for controlling the throttle valve opening of the engine of FIG. 2 together with FIG. 7.

9 is a flowchart illustrating the contents of an automatic engine brake throttle processing routine of FIG.

10 is an example of a shift map for switching the shift speed of the automatic transmission shown in FIG.

11 is a flowchart for calculating a throttle valve opening degree TA1 in step R4 of FIG.

12 is an example of a data map used when obtaining the first correction coefficient in step SH1 of FIG.

FIG. 13 is an example of a data map used when obtaining the second correction coefficient in step SH2 of FIG. 11.

14 is an example of a data map used when obtaining a third correction coefficient in step SH3 of FIG.

FIG. 15 is an example of a data map used when obtaining the throttle valve opening degree TAm in step R5 of FIG. 9.

16 is basic data for creating the data map of FIG.

FIG. 17 is data showing the output characteristics of the engine used to obtain the basic data of FIG.

FIG. 18 is an example of a data map used when obtaining the throttle valve opening degree TA2 in step R12 of FIG.

FIG. 19 is an example of a data map used when obtaining the throttle valve opening change timing time T2 in step R13 of FIG.

[Explanation of symbols]

 10: Engine 20: Throttle valve 34: Transmission control computer 35: Throttle control computer 78: Automatic transmission V: Vehicle speed Vm: Target vehicle speed θ: Throttle valve opening ΔTA: Adjustment amount Steps R4, R6: Throttle control means Step SH1 to SH6: correction means

Claims (1)

[Claims] 1. A throttle valve opening degree according to a deviation of an actual vehicle speed to a predetermined target vehicle speed when a predetermined traveling control condition including at least an accelerator OFF state is satisfied. In a vehicular travel control device having a throttle control means for performing feedback control of the throttle valve opening degree, an adjustment amount of the throttle valve opening, which is obtained according to the deviation of the vehicle speed by the feedback control, is obtained as a driving force change corresponding to the deviation. As described above, a travel control device for a vehicle, which is provided with correction means for performing correction based on a running state of a vehicle including at least one of a gear ratio of an automatic transmission, an engine speed, and a throttle valve opening.