JPH061166A - Engine brake force control device - Google Patents

Abstract

PURPOSE:To prevent sudden change of engine brake force at the time of down- shift by providing an engine output increase means to increase an engine output in such a way that 4 drive force before the down-shift is almost equal to the drive force after the down-shift at least when the down-shift is completed. CONSTITUTION:In performing down-shift for increasing engine brake force when an accelerator is off, a throttle valve 20 is controlled to be opened by a throttle control computor 35 to a throttle valve opening at which drive force after the down-shift becomes equal to or a little smaller than the drive force before the down-shift. Almost the same engine brake force as that before the down-shift is thus applied after the down-shift, thereby shock caused by sudden increase of the engine brake force is reduced to improve riding comfortableness.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine braking force control device, and more particularly to engine braking force control when increasing engine braking force by downshifting.

[0002]

2. Description of the Related Art Automatic vehicles equipped with an automatic transmission having a plurality of gears are often used. However, such an automatic transmission generally has a gear based on an accelerator operation amount or a throttle valve opening and a vehicle speed. It is supposed to be changed. FIG. 10 is an example of a shift map of an automatic transmission having four shift stages. The shift stages can be switched based on the accelerator operation amount and the vehicle speed. The solid line is the shift map on the upshift side and the broken line is the shift map. It is a shift map on the downshift side. Such a shift map is usually designed to upshift depending on the vehicle speed even when the accelerator operation amount is zero, that is, in the OFF state. Therefore, even when the accelerator pedal is released on a downhill, sufficient engine braking force is obtained. If the vehicle speed increases without being obtained, there is a problem that the engine braking force further decreases due to an upshift. As a countermeasure against this, if the acceleration of the vehicle is other than negative or the vehicle speed continues to increase for a certain period of time with the accelerator off, the engine braking force is increased by downshifting to increase the gear ratio of the automatic transmission. For example, Japanese Patent Laid-Open No. 62-246650 and Japanese Patent Laid-Open No. 6-246650
It is disclosed in Japanese Patent Publication No. 1-103044. Further, in an automatic vehicle in which such automatic engine braking control is not performed, the driver performs the downshift by turning off the overdrive switch or switching the shift lever from the D range to the S range or the L range. This increases the engine braking force.

[0003]

However, when the engine braking force is increased by the downshift in this way, the engine rotation speed is increased according to the change of the gear ratio of the automatic transmission accompanying the downshift, and the engine brake is increased. There was a problem that the force suddenly increased, a shock occurred, the riding comfort was not good, and the engine braking was too effective, requiring accelerator operation.

The present invention has been made in view of the above circumstances, and an object of the present invention is to prevent an abrupt change in the engine braking force during a downshift for increasing the engine braking force.

[0005]

To achieve the above object, the engine braking forces should be made substantially equal before and after downshifting. The present invention is as shown in the claim correspondence diagram of FIG. When the automatic transmission is downshifted to the low speed stage where the engine braking force acts with the accelerator substantially OFF, the driving force before the downshift and the driving force after the downshift are substantially at least when the downshift is completed. It is characterized by having an engine output increasing means for increasing the engine output so as to be equal.

[0006]

In such an engine braking force control device, the engine output increasing means is used so that the driving force before the downshift and the driving force after the downshift become substantially equal at least when the downshift is completed. Since the engine output is increased, the engine braking force before and after the downshift is made substantially the same, and a rapid increase in the engine braking force due to the downshift is prevented. As a result, the shock caused by the sudden increase in the engine braking force is reduced, and the engine braking force is smoothly increased by the subsequent gradual control of the engine output, etc., so that an appropriate engine braking force can be obtained. It is also possible.

[0007]

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

In FIG. 2, in a combustion chamber 12 of a 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. 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 comprises 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" range, the manual shift valve of the hydraulic control circuit 150 is switched to establish the reverse gear.

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.

The shift control and throttle control by the transmission control computer 34 will be described below in detail 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.

The automatic transmission 7 is executed 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 automatic engine braking control is being executed, step S41 is executed subsequently to 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 R8 of FIG. 9 when the downshift is performed to increase the engine braking force in the automatic engine braking control, and when the downshift shift output is performed, the flag F4 of FIG.
Is set to "0" in step S31, and if F4 = 0, the flag F2 is set to "0" in step S44 to complete the shift determination, and if F4 = 1, step S43.
To execute. In step S43, the next low speed stage on which the engine brake acts as the next shift stage, that is, in the case of 2nd or 1st, the shift 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 5% or less. In step S26, it is determined whether or not the next shift speed set in step S15 is the O / D shift speed. The lower limit vehicle speed V1 and the upper limit vehicle speed V2 define a vehicle speed range in which special control for engine braking is performed. The lower limit vehicle speed V1 is set to, for example, about 20 km / h, and the upper limit vehicle speed V2 is, for example, about 110 km / h. Is set to. If even one of the steps S21 to S26 is NO, in step S28, the change of the next shift stage set in step S15 is not performed in step S27, but the determination in steps S21 to S26 is made. If all are YES, the next gear is changed to "3rd" in step S27. Note that the above step S26 is the same as step
It is determined whether or not the next shift stage set in step 5 is O / D. Even in the cycle after the next shift stage is changed from O / D to 3rd in step S27, the determination in step S26 is Y.
It becomes ES.

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.

Also, 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 below is executed,
If any one of them is NO, step SS6 of FIG.
Flag F3 is set to "0" and flag F5
Is set to "0" and normal throttle control is performed in step SS7. The normal throttle control in step SS7 is performed by the accelerator operation amount A indicated by the accelerator operation amount signal SAc.
Based on c, the throttle valve opening TA (Ac) is calculated from a predetermined map or an arithmetic expression, and the throttle valve opening TA (Ac) is set to the target throttle valve opening TA ^* , and the target throttle opening TA (Ac) is set. A throttle command signal SQ indicating the valve opening degree TA ^* is output to the throttle control computer 35. Throttle control computer 3
Reference numeral 5 indicates the actual throttle valve opening θ of the throttle valve 20 by the feedback control or the like and the throttle command signal S
The target throttle valve opening TA ^* represented by Q, that is, TA
Throttle control signal DT to match (Ac)
A is output to the throttle valve 20.

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 R2 and R4 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 operated based on the brake signal SB. If the brake is OFF, that is, if the pedal is not operated, 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 R8 of FIG. 9 when the downshift is performed to increase the engine braking force. When the flag F6 = 0, the flag F3 is already set to "1" in step SS17. It is determined whether it is "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 (1) 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.
When the following expression (1) is satisfied, the gear change is not being performed, and when the following expression (1) is not satisfied, the gear change 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 (1) is set to satisfy a predetermined range in consideration of detection errors of the rotational 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.

[0036]

## EQU1 ## N _T ≈N _O × i (1)

In the automatic engine brake throttle processing routine of step SS21, the vehicle speed V is substantially equal to the target vehicle speed Vm in this embodiment so that the actual vehicle speed V does not exceed the target vehicle speed Vm set in step SS10 of FIG. The throttle valve opening θ is feedback-controlled so as to coincide with each other, and is specifically executed according to the flowchart of FIG. In step R1 of FIG. 9, it is determined whether the actual throttle valve opening θ represented by the throttle valve opening signal Sθ is smaller than a predetermined judgment value θ1. The determination value θ1 is a small value of about 5% or less, and can be determined using an idle signal or the like indicating that the throttle valve opening θ is substantially fully closed. Then, when θ ≧ θ1, that is, when the engine braking force can be increased by closing the throttle valve opening θ, step R2 is executed, and according to the deviation between the target vehicle speed Vm and the current vehicle speed V. Then, the throttle valve opening TA1 (%) for making the vehicle speed V substantially equal to the target vehicle speed Vm is calculated according to the calculation formula of the feedback control.

In the next step R3, based on the current shift speed and the target vehicle speed Vm, the throttle valve opening that can maintain the target vehicle speed Vm in flatland traveling, that is, the driving force in consideration of running resistance becomes zero. Throttle valve opening TAm
(%) Is calculated by map interpolation from a previously stored data map as shown in FIG. 11, for example, and it is determined whether or not the throttle valve opening TA1 is smaller than the throttle valve opening TAm. The data map of FIG. 11 is obtained by determining 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 shown in FIG. 12, which is experimentally obtained in advance. . 12
The data indicates that in the vehicle equipped with the engine having the output characteristics shown in FIG. 13, the gear position of the automatic transmission 78 is O / D.
(Total gear ratio = 2.8905), gear transmission efficiency is 0.855, and tire effective radius is 0.306 m. For example, when the vehicle speed is 80 km / h, the throttle valve opening TAm (%) is flat. The throttle valve opening (angle) at point B, which matches the running resistance on the ground, is about 7.4 °, so if this is converted to 80% of full opening,
(7.4 / 80) × 100 = 9.3. That is,
In the data map of FIG. 11, the vehicle speed is 8 at the O / D shift stage.
The throttle valve opening TA _{45 at} 0 km / h is specifically 9.3%, and thus the throttle valve opening TA _{41 to} TA _{47 at} each vehicle speed in the O / D shift stage can be obtained. ing. For the 3rd gear and the 2nd gear and 1st gear where the engine brake acts, the above O /
As in the case of the D shift stage, the throttle valve opening TA ₃₁
TA ₃₇ , TA _{21 to} TA ₂₇ , TA _{11 to} TA ₁₇ are required. As is clear from the data in FIG. 12, the throttle valve opening degree TAm increases as the vehicle speed increases, and if the vehicle speed is the same, the throttle gear opening TAm increases as the gear ratio increases and the shift speed decreases.

If TA1 <TAm, the throttle valve opening degree TA1 is set to the target throttle valve opening degree TA ^* in step R4, 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 R2, R
By repeatedly executing 3 and R4, 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

On the other hand, the determination in step R3 in the case of TA1 ≧ TAM sets NO, a throttle valve opening TAM in step R5 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 becomes YES and steps R6 and thereafter are executed. In step R6, it is determined whether or not the current vehicle speed V is higher than the target vehicle speed Vm. If V> Vm, steps R8 and below are executed.
If V≤Vm, that is, if the engine is being decelerated by the engine braking action due to the throttle valve 20 being fully closed, there is no need to perform a downshift, so the target throttle valve opening TA ^{* is set} to 0 in the subsequent step R7. , Keep the throttle valve 20 fully closed. Step R8
Then, the flag F4 instructing the downshift in order to increase the engine braking force is set to "1", and the flag F6 representing the throttle control at the time of the downshift is set to "1". When the flag F4 is set to "1", step S43 of FIG. 5 is executed, and when the flag F6 is set to "1", steps SS24 and thereafter of FIG. 8 are executed. .

In the next step R9, the throttle valve opening degree TA2 (%) at which substantially the same driving force is obtained before and after the downshift is performed based on the type of downshift and the current vehicle speed V, for example, as shown in FIG. It is calculated by map interpolation from a predetermined data map as shown in 14. The data map of FIG. 14 is based on the driving force data shown in FIG.
Driving force when the throttle valve 20 is fully closed at the gear before the downshift (in this case, it acts as a braking force)
Throttle valve opening degree TA2 (%) that is the same as or slightly smaller than the driving force, in other words, the driving force at which the engine braking force is the same as or slightly greater than
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, the driving force when the accelerator is off is about −300 N as indicated by point C in FIG.
When downshifting to the rd gear, the vehicle speed is 80 km / in the data corresponding to FIG. 12 in the case of 3rd.
The throttle valve opening degree TA2 is a value of the throttle valve opening degree at which the above-mentioned driving force, that is, a driving force equal to or slightly smaller than −300 N is obtained at h. The throttle valve opening degrees TA2 _{31 to} TA2 _3n at the time of “O / D → 3rd” gear shift in FIG. 14 are thus determined for each vehicle speed V _{1 to} V _n , and “3rd →
2nd (S3ON) "Throttle valve opening TA2 during gear shifting
_{21 to} TA2 _2n and throttle valve opening TA2 _{11 to} TA2 _1n at the time of “2nd → 1st (S3 ON)” shifting are also 2nd
It is determined in the same manner as above by using the driving force data of the shift speed and the first shift speed. This throttle valve opening TA2 is
For the same type of shift, the higher the vehicle speed, the higher the speed. At the same vehicle speed, the downshift on the low speed side is higher than the downshift on the high speed side.

Further, in the subsequent step R10, 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 applying, 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 R8, in subsequent cycles, step SS1 in FIG.
The judgment of 6 is NO, and step SS24 is executed.
In step SS24, the shift output for the downshift is performed in step S30, and the next step S24 is executed.
In step 31, it is determined whether the flag F4 is "0", and the timer Tb is reset in step SS25 until F4 = 0, and when F4 = 0, step SS
Perform steps 26 and below. 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 gear shift output is performed, In step SS26, the content measured by the timer Tb is the throttle valve opening change timing time T
Judge whether the number is 2 or more. And the timer Tb
When the timing content of the time reaches the change timing time T2, the throttle valve opening degree TA2 is set to the target throttle valve opening degree TA ^* in step SS27, and the throttle command signal SQ representing the target throttle valve opening degree TA ^* is used for throttle control. By outputting it to the computer 35, the actual throttle valve opening θ of the throttle valve 20 is controlled to be the throttle valve opening TA2. Further, in the next step SS28, whether the gear shift is completed from the equation (1) based on the current gear ratio i and the rotational speeds N _T and N _O after the downshift gear shift output is performed. When it is determined whether or not 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.

As described above, in this embodiment, when the downshift is performed while the accelerator is off to increase the engine braking force, the driving force after the downshift is the same as or slightly smaller than the driving force before the downshift. Since the throttle valve 20 is controlled to open up to the throttle valve opening TA2, substantially the same engine braking force as before the downshift is applied even after the downshift, and the shock caused by the rapid increase in the engine braking force is reduced. The riding comfort is improved. Particularly, in the present embodiment, by executing the steps after step R2 after the downshift,
Throttle valve 2 so that vehicle speed V matches target vehicle speed Vm
Since 0 is feedback controlled, an appropriate engine braking force can be obtained, and there is no inconvenience that the engine braking force becomes excessive due to the downshift and the accelerator operation is required, and the driving operation becomes extremely easy. .

Further, in this embodiment, the engine speed N is adjusted in accordance with the timing at which the clutch C and the brake B on the high speed stage side released by the downshift start to slip.
Since the timing for controlling the opening of the throttle valve 20 is determined so that E increases, even during the gear shift process in which the engagement switching of the clutch C and the brake B is performed, the inertia torque of the engine 10 or the like temporarily changes. The increase in braking force is suppressed, the engine speed NE is rapidly increased in combination with the torque transmission from the drive wheel side, the shift time is shortened, and the life of the friction material of the clutch C and the brake B is improved. To do.

FIG. 16 shows a vehicle speed of 55 km / h on an 8% downhill due to the automatic engine braking control of this embodiment.
7 is a time chart showing a change in rotational speed and a change in driving torque of each part when a downshift is performed from the 3rd shift stage to the 2nd shift stage at the time of gear shift, that is, the friction engagement device (clutch C ₂ ) Is about 0.69 sec from the start of slipping until the friction engagement device (brake B ₁ ) on the low speed stage is completely engaged.

The line oil pressure of the oil pressure control circuit 150 is generally controlled according to the throttle valve opening θ, and when the throttle valve 20 is opened and controlled as described above, the line oil pressure is increased. As a result, the engaging hydraulic pressures of the clutch C and the brake B also increase, so that the clutch C and the brake B on the low speed stage side are suddenly completely engaged, and the shift time is further shortened. However, in that case, a large shift shock is likely to occur. Therefore, in this embodiment, when the throttle valve 20 is opened in step SS27, the line oil pressure is controlled to a low oil pressure when the throttle valve 20 is fully closed. ing.

In this embodiment, the portion for executing steps R9, R10, SS26, SS27, SS28 of the series of signal processing by the transmission control computer 34 is the engine output increasing means together with the throttle control computer 35 and the throttle valve 20. Are configured.

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, the automatic engine braking control is described in the above embodiment, but the driver turns off the overdrive switch when the accelerator is substantially off, or switches the shift lever from the D range to the S range or the L range. The present invention is similarly applied to the case where a downshift is performed by changing the speed of the engine, and in that case as well, the increase control of the engine output reduces the shock at the time of a gear shift due to the abrupt change of the engine braking force. After the shift is completed, it is desirable that the throttle valve 20 be gradually closed so that the engine braking force increases smoothly.

Although the engine output is increased by controlling the opening of the throttle valve 20 in the above embodiment, an engine auxiliary machine such as an alternator may be used or the idle speed control valve 38 may be controlled to open. It is also possible to increase the engine output.

Further, in the above embodiment, the throttle valve opening θ
Although the vehicle controlled by the throttle control computer 35 has been described above, the present invention is also applicable to a vehicle in which the throttle valve 20 is mechanically connected to an accelerator pedal to open and close. The configuration of the automatic transmission 78 and the number of gears can be changed as appropriate.

Further, in the above embodiment, the throttle valve opening TA2 is set based on the type of shift and the vehicle speed V, but it depends on the operating state of the EGR (exhaust gas recirculation device) and the engine cooling water temperature. The engine output changes due to engine friction torque changes, and due to changes in the oil pump drive torque due to the A / T oil temperature THO, changes in the friction torque of the torque converter 110 and the input shaft 120, changes in auxiliary machinery drive torque such as air conditioners and alternators, etc. Even if the throttle valve opening θ is the same, the torque required for rotating and blowing up the input shaft 120 changes, so the throttle valve opening TA2 is taken into consideration in consideration of these operating states.
Can also be set.

Further, in the above embodiment, the throttle valve opening change timing time T2 is set so that the engine rotational speed NE increases at substantially the same time when the friction engagement device on the high speed stage side, which is released during a downshift, starts to slide. However, it suffices that it is determined that the engine output increases at least from the start of the slip to the time when the friction engagement device on the low speed stage side is completely engaged. It is sufficient that the engine output increase control is performed so that the driving force before and after the gear shift is substantially equal when the gear is completely engaged, that is, when the gear shift is completed. For example, at the initial stage of gear shifting when the frictional engagement device on the high speed side starts to slide, the throttle valve opening TA2 is added with a predetermined value ΔTA in consideration of inertia of the crankshaft 118, the torque converter 110, and the like. It is also possible to control the opening of the valve 20 or temporarily open the throttle valve 20 largely until the engine speed rises.

Further, in the above-mentioned embodiment, the timer Tb measures the elapsed time with the shift output in step S30 as the measurement start time. However, the measurement start time is determined when the downshift, such as step R8, is performed. As a matter of course, the elapsed time may be measured as a matter of course, and the opening control of the throttle valve 20 may be started by detecting a slip of the frictional engagement device on the high speed stage side by a rotation speed sensor, a hydraulic pressure sensor or the like. good.

Further, in the above embodiment, the automatic engine braking control of step SS8 and thereafter is executed on condition that the automatic engine braking pattern is selected by the pattern select switch 70. When the driving pattern of is selected, automatic engine braking control is performed,
The automatic engine braking control may be executed regardless of the type of driving pattern. Of course, the engine brake control switch may be provided independently of the pattern select switch 70.

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

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.

In the above embodiment, step S2 in FIG.
Even if the next gear is changed to 3rd in step 7, if the accelerator is depressed before reaching the gear shift timing time T1, the next gear is returned to O / D in step S28. When is changed to 3rd, step S30 may be immediately executed to output the gear shift even before the gear shift timing time T1 is reached.

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. However, the target vehicle speed Vm does not need to be completely matched with the vehicle speed V, and measurement is performed. The target vehicle speed Vm may be set by adding or subtracting a predetermined value to the vehicle speed V in consideration of an error or the like.

In the above embodiment, the vehicle speed V is set to the target vehicle speed V.
Although the throttle valve opening θ is feedback-controlled so as to match m, the throttle valve opening θ may be increased or decreased by a predetermined constant amount ΔTA, or the vehicle speed V
It is also possible to use other control methods, such as decreasing the throttle valve opening θ by a constant amount ΔTA so that does not exceed the target vehicle speed Vm. Step S
The constant value Vf of S9 is determined in consideration of the variation of the vehicle speed V accompanying the control of the throttle valve opening θ. The present invention can be similarly applied to other automatic engine braking control, such as performing downshift so that the acceleration becomes negative and increasing control of the engine braking force.

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 implemented 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 an engine braking force 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.

FIG. 11 is an example of a data map used when obtaining the throttle valve opening degree TAm in step R3 of FIG. 9.

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

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

FIG. 14 is an example of a data map used when determining a throttle valve opening degree TA2 in step R9 of FIG. 9.

FIG. 15 is an example of a data map used when determining a throttle valve opening change timing time T2 in step R10 of FIG.

16] FIG. 16 is a diagram showing an example in which, in the embodiment of FIG.
6 is a time chart showing changes in the rotational speed, driving torque, etc. of each part when a downshift is performed to the d shift stage.

[Explanation of symbols]

10: Engine 20: Throttle valve 34: Transmission control computer 35: Throttle control computer 78: Automatic transmission TA2: Throttle valve opening T2: Throttle valve opening change timing time Steps SS26, SS27, SS28, R9, R1
0: Engine output increasing means

Claims (1)

[Claims] 1. When the automatic transmission is downshifted to a low speed stage where engine braking force is applied with the accelerator being substantially off, the driving force before the downshift and the driving after the downshift are performed at least when the downshift is completed. An engine braking force control device comprising engine output increasing means for increasing an engine output so that the force and the force are substantially equal.