JP2964784B2 - Engine brake force control device - Google Patents

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 an engine braking force control for increasing an engine braking force by downshifting.

[0002]

2. Description of the Related Art Automatic vehicles equipped with an automatic transmission having a plurality of gear positions are often used. Generally, such automatic transmissions have a gear position based on an accelerator operation amount or a throttle valve opening and a vehicle speed. It has been changed. FIG. 10 is an example of a shift map of an automatic transmission having four shift stages, in which the shift stages are switched based on the accelerator operation amount and the vehicle speed. It is a shift map on a downshift side. Since such a shift map normally shifts up according to the vehicle speed even when the accelerator operation amount is zero, that is, in the OFF state, a sufficient engine braking force can be obtained even when the accelerator pedal is released on a downhill. If the vehicle speed increases without being obtained, there is a problem that the engine brake force is further reduced due to an upshift. As a countermeasure, when the acceleration of the vehicle is non-negative or the vehicle speed keeps increasing for a certain period of time while the accelerator is off, the engine braking force is increased by downshifting to increase the gear ratio of the automatic transmission. For example, Japanese Patent Application Laid-Open Nos. Sho 62-246650 and
It is disclosed in, for example, JP-A-1-103044. In an automatic vehicle in which such an automatic engine brake control is not performed, the driver performs an down-shift by turning off an overdrive switch or switching a shift lever from a D range to an S range and an L range. As a result, the engine braking force is increased.

[0003]

However, when the engine braking force is increased by downshifting as described above, the engine rotational speed is increased in accordance with the change in the gear ratio of the automatic transmission accompanying the downshift, and the engine braking speed is increased. Since the force suddenly increases, there is a problem that a shock is generated and the riding comfort is not good, and the engine brake is too effective and an accelerator operation is required in some cases.

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

[0005]

In order to achieve the above object, it is sufficient that the engine braking force is substantially equal before and after the downshift, and the present invention is applied to a vehicle as shown in FIG. When the automatic transmission is downshifted to the low gear stage where the engine braking force acts with the accelerator substantially in the OFF state, at least at the completion of the downshift, the driving force before the downshift and the driving force after the downshift are substantially equal. It is characterized by having engine output increasing means for increasing the engine output so as to be equal.

[0006]

In such an engine braking force control apparatus, at least at the time of the completion of the downshift, the engine output increasing means is provided so that the driving force before the downshift is substantially equal to the driving force after the downshift. Since the engine output is increased, the engine braking force before and after the downshift is made substantially the same, and a sudden increase in the engine braking force associated with 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 decrease control of the engine output, 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 below in detail 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 sucked in through the intake valve 28,
A 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 amount of intake air, and outputs a signal indicating the amount of intake air to the computer 32 for engine control. Throttle valve 20
Is for continuously changing the amount of air sucked into the engine 10. The throttle valve opening .theta. Is controlled in accordance with a throttle control signal DTA supplied from a throttle control computer 35. The valve 20 is provided with a throttle position sensor 36, and outputs a throttle valve opening signal Sθ indicating 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 disposed in parallel with the throttle valve 20 and has an idle speed control valve 3
8 and an engine control computer 32
The opening degree of the idle speed control valve 38 is controlled by the control, whereby the amount of air flowing bypassing the throttle valve 20 is adjusted, and the engine speed during idling is controlled. The injection timing and injection amount of the fuel injection valve 30 are also controlled by the engine control computer 32. An intake air temperature sensor 40 for measuring the temperature of the intake air is provided upstream of the air flow meter 16, and a signal representing the intake air temperature is sent to an engine control computer 32.
Output to

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

The computer 32 for engine control, the computer 34 for transmission control, and the computer 35 for throttle control are all CPU, RAM, R
The transmission control computer 34 includes an OM, an input / output interface circuit, an A / D converter, etc., and performs signal processing according to a program stored in the ROM while utilizing a temporary storage function of the RAM. Are the above signals, the pattern signal SP representing the selected pattern from the pattern select switch 70, the brake signal SB representing that the brake has been depressed from the brake lamp switch 72, and the overdrive switch 74 to the O / D gear. O / indicating the shift permission of
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 computer 32 for engine control and the computer 35 for throttle control. The pattern select switch 70 has at least an automatic engine brake pattern for automatically increasing the engine brake on a downhill or the like, a power pattern for controlling the shift of the automatic transmission 78 by a shift map emphasizing the power performance, and a fuel efficiency. The driver selects and operates a favorite traveling pattern from a plurality of predetermined traveling patterns, such as an economy pattern in which gear shifting control is performed according to an emphasized shift map. The brake lamp switch 72 is provided near the brake pedal, and is turned on and off depending on whether or not the brake pedal is depressed.
It is configured by an ON-OFF switch or the like that switches F.

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

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

[0013] The clutch C ₀ -C ₂ and the brake B
_{0 to} B ₃ (hereinafter, unless otherwise specified, the clutch C,
The brake B) is a hydraulic friction engagement device that is controlled to be engaged by a hydraulic actuator such as a multi-plate clutch or a band brake so that hydraulic oil is supplied from a hydraulic control circuit 150 to the hydraulic actuator. Has become. The hydraulic control circuit 150 is provided with a number of switching valves and the like, and the solenoids S1, S2, and S3 are switched between energized and de-energized in accordance with signals from the transmission control computer 34, thereby switching the hydraulic circuit. The engagement of the clutch C and the brake B is selectively controlled, and one of the four forward speeds is established, as shown in FIG. In FIG. 4, the mark “○” in the column of solenoid means excitation, and the mark “○” in the column of clutch and brake means engagement. "D", "S",
"L" is the operating range of the shift lever in the driver's seat,
In the “D (drive)” range, shift control is performed in four steps from 1st to O / D. In the “S (second)” range, shift control is performed in two steps, 1st and 2nd.
In the (low) range, the gear is fixed to the first shift speed. The gear ratio (the rotation speed of the input shaft 120 / the rotation speed of the output shaft 146) is the largest at the first time, 2nd, 3rd, O / D.
And the speed ratio of 3rd is 1.0. In the “D” range, the engine brake operates at 3rd and O / D, and does not operate at 1st and 2nd due to the operation of the one-way clutches F ₂ and F ₁ . 1st),
In (2nd), when the solenoid S3 is excited, the brakes B ₃ and B ₁ are engaged, and the engine brake operates. 2n of "S" range
The engine brake is applied even in the first and d 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 has an input shaft 120, that is, the torque converter 11
Detects the rotational speed N _T of the turbine impeller of 0, the rotational speed sensor 82 is for detecting the rotational speed N _O of the output shaft 146, the rotational speed N _T, respectively, the rotational speed signal representing the N _O It outputs SN _T and 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",
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 hydraulic 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, and the A / T oil temperature T
An oil temperature signal STHO representing HO is output to the transmission control computer 34.

The control computers 32, 3
Necessary information is exchanged between 4 and 35. The throttle valve opening signal Sθ, the engine rotation speed signal SNE, and the accelerator operation amount signal SAc are at least one of the control computers 32, 34, Or, it may be supplied to 35. Further, various other signals indicating the driving state of the vehicle, such as the steering angle of the steering wheel, the gradient of the road surface, the exhaust temperature, etc., may be taken in and used for engine control, shift control of the automatic transmission 78, and throttle control. It is possible.

The engine control computer 32 calculates the intake air amount, the throttle valve opening θ, the engine 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. Amount Ac
In accordance with, for example, the fuel injection valve 3 based on a data map or an arithmetic expression determined in advance to reduce fuel consumption and harmful exhaust gas while securing necessary engine output,
It controls the fuel gas injection amount and injection timing by 0, the ignition timing by the igniter 48, the idle speed by the idle speed control valve 38, and the opening and closing timing of the intake and exhaust valves 28 and 42 by the variable valve timing mechanism. 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 speed represented by the O / D signal SO. Whether or not a shift can be performed, accelerator operation amount Ac, automatic transmission 78
Based like the output shaft rotation speed N _O of the solenoid S
By switching between excitation and non-excitation of S1, S2, and S3, the shift speed of the automatic transmission 78 is switched. The transmission control computer 34 also switches between a completely engaged state, a slipped state and a released state by duty-controlling a solenoid (not shown) provided in the hydraulic control circuit 150 also for the lock-up clutch of the torque converter 110. In addition, the throttle valve opening θ of the throttle valve 20 is controlled in accordance with the accelerator operation amount Ac, or when the accelerator operation amount Ac is zero, the throttle valve opening θ is adjusted to control the engine braking force. For this purpose, a 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 in accordance with the throttle command signal SQ.
It outputs TA.

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

Step S1 and subsequent steps in FIG.
In the step of determining whether or not to shift to the eighth gear, step S40 is NO, that is, the flag F3
Is executed when is not “1”. The flag F3 is set as shown in FIG.
Is set to "1" in step SS14 or SS19 in FIG. 8 when all of the conditions of steps SS1 to SS5 are satisfied and any one of the conditions of steps SS1 to SS5 is satisfied. If not, it is set to "0" in step SS6,
Step S1 and subsequent steps are executed in the case of normal shift control in which automatic engine brake control is not performed.

In step S1, it is determined based on the O / D signal SO whether or not a shift up to the O / D gear is possible, and the O / D signal SO is turned off, that is, the O / D gear is prohibited. If there is, the current O /
It is determined whether or not the gear is the D gear. The current gear position is determined based on the output state of the excitation signal for exciting the solenoids S1, S2, and S3. Where O
The / D shift stage means that the overdrive switch 74 has been turned off during traveling at the O / D shift stage. In this case, the flag F2 is set at step S14.
Is set to "1", "3rd" is set as the next gear in step S15. If the determination in step S1 is NO, that is, if the O / D gear is allowed, or if the determination in step S1 is YES, the current gear is not the O / D gear and the determination in step S2 is NO and the current 3rd
Otherwise, if the determination in step S3 is NO, step S4 is subsequently executed. In step S4, it is determined whether or not the current shift speed is the O / D shift speed. If not, the process proceeds to step S5 to determine whether or not to perform an upshift. .

In step S5, a predetermined upshift map is searched to determine an upshift vehicle speed Vu. The upshift map is predetermined for each type of shift based on the accelerator operation amount Ac and the vehicle speed V, as indicated by the solid line in FIG. 10. As the accelerator operation amount Ac decreases, the vehicle speed V increases. It is designed to upshift to the high speed stage. Upshift 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 And compare
It is determined whether to perform an upshift. That is, V ≦
If Vu, it is not necessary to perform an upshift, and it is determined in step S8 whether or not the current shift stage is 1st. If it is 1st, the flag F1 is set to "0" in step S9 and a series of shift determinations is completed. However, if V> Vu, the flag F1 is set to "1" in step S7, and then, in step S15, a gear higher than the current gear is set as the next gear. In this case, even if the current gear position is, for example, 2nd, the accelerator operation amount Ac rapidly decreases before the gear position is switched to 3rd after the gearshift to 3rd is determined. If it exceeds the “3 → O / D” upshift line, the O / D shift speed is set. In step S5, the upshift vehicle speeds Vu for all the upshift lines are obtained from the current accelerator operation amount Ac. In step S6, the respective upshift vehicle speeds Vu and the current vehicle speed V are compared to determine the upshift speed change. Do it.

If the determination in step S3 is YES,
If the determination in step S4 is YES, or
If the determination in step 8 is NO, step S10 and subsequent steps are executed to determine whether to perform downshifting. Step S
At 10, a predetermined downshift map is searched to determine a downshift vehicle speed Vd. The downshift map is determined in advance for each type of shift based on the accelerator operation amount Ac and the vehicle speed V, as indicated by the broken line in FIG. 10. As the accelerator operation amount Ac increases, the vehicle speed V decreases. The gear shifts down to the lower gear. The shift-down vehicle speed Vd is determined by the accelerator operation amount A
determined according to downshift map based on the c, at the next step S11, it compares the current vehicle speed V and the downshift vehicle speed Vd corresponding to the output shaft rotational speed N _O, determines whether to perform a downshift I do. That is,
If V> Vd, there is no need to perform a downshift, and the flag F2 is set to “0” in step S13 to end a series of shift determinations. If V ≦ Vd, step S13 is executed.
After setting the flag F2 to "1" in step 12,
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 position is, for example, O / D, the accelerator operation amount Ac sharply increases after the gear shift determination to 3rd is performed and before the gear shift to 3rd is actually performed. "2 ← 3"
When the vehicle goes beyond the downshift line, the second gear is set. In step S10, the current accelerator operation amount Ac
Downshift vehicle speed V for all downshift lines from
In step S11, the respective downshift vehicle speeds Vd are compared with the current vehicle speed V to determine the downshift speed.

If step S40 is YES, that is, if the automatic engine brake control is being executed, step S41 is executed following step S40.
It is determined whether the flag F5 is "0". The flag F5 is
If the automatic engine brake control is executed with all the conditions of steps SS1 to SS5 in FIG. 7 satisfied and the brake is depressed, it is set to “1” in step SS23 in FIG. The flag F is set to "0" in step SS6 or SS12,
If 5 = 0, step S42 is executed and the flag F5
If = 1, step S45 is executed. In step S45 executed when the brake is depressed, a predetermined downshift map during engine braking is searched to determine a downshift vehicle speed Ved during engine braking. The downshift map at the time of engine braking is predetermined for each type of shift based on the accelerator operation amount Ac and the vehicle speed V, similarly to the normal downshift map shown by the broken line in FIG. ,
It is shifted to a higher vehicle speed side than a normal downshift map, and it is easy to downshift. Shift down vehicle speed Ve
d is compared, determined according to downshift map at the time of engine braking based on the accelerator operation amount Ac, at the next step S46, the current corresponding to the output shaft rotation speed N _O of the vehicle speed V and the downshift vehicle speed Ved Then, it is determined whether to perform a downshift. That is,
If V> Ved, there is no need to perform a downshift, and the flag F2 is set to “0” in step S44 to end the shift determination. If V ≦ Ved, step S4
After setting the flag F2 to "1" in step 7, the process proceeds to step S4
In step 8, a shift speed lower than the current shift speed is set as the next shift speed. The gear set here is the one where the engine brake acts, and in the second or first gear, the gear shown in parentheses in FIG. 4 is set. In this case, even if the current gear position is, for example, O / D, the vehicle speed V suddenly decreases after the gear shift determination to 3rd is made and before the gear shift to 3rd is actually performed. When exceeding the “2 ← 3” downshift line, the second shift speed is set. In step S45, the downshift vehicle speeds Ved for all the downshift lines are obtained from the current accelerator operation amount Ac. In step S46, each downshift vehicle speed Ved is compared with the current vehicle speed V to determine the downshift shift. Do it.

In step S42 executed when the brake 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 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, FIG.
Is set to "0" in step S31, and if F4 = 0, the flag F2 is set to "0" in step S44 to end the shift determination, and if F4 = 1, the process proceeds to step S43.
Execute In step S43, the next low speed position where the engine brake acts as the next speed position, that is, in the case of 2nd or 1st, the speed position shown in parentheses in FIG. 4 is set.

When the next gear is set in step S15, S43 or S48, the gear shift timing time T1 is set in step S16.
This shift timing time T1 is a delay time from when the shift is determined to when the shift output is performed to actually switch the shift stage (step S30), and that a plurality of shifts are performed in a short time (multi-shift). ), And when the upshift to the O / D gear is made when the accelerator pedal is quickly released to apply the engine brake on the downhill, before the upshift is actually performed. When the accelerator operation amount Ac becomes substantially zero, it is provided to prohibit an upshift to the O / D shift speed.
A fixed value may be set in advance, but different times may be set according to the type of shift, such as upshift, downshift, or downshift in automatic engine brake control. Further, it may be set by a map, an arithmetic expression, or the like according to the accelerator operation amount Ac at the time of the shift determination, the vehicle speed V, the shift speed, and the like.

Next, the flow chart of FIG. 6 for actually switching the gears will be described. FIG. 6 shows 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, it is determined whether or not the flag F1 is "1", that is, the upshift shift determination. Is determined. If the flag F1 is "1", the steps from step S21 are executed, but if not, the 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 performed to increase the engine braking force. If the flag F4 is "1", the steps from step S21 are executed. Otherwise, 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 determined to be "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, the accelerator operation amount Ac indicated by the accelerator operation amount signal SAc is substantially zero, specifically, a detection error. In consideration of the above, it is determined whether or not the speed 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 set to, for example, about 110 km / h. Is set to If any one of the above steps S21 to S26 is NO, in step S28, the change of the next shift speed set in step S15 in step S27 is not performed, but the determination in steps S21 to S26 is made. If all are YES, the next gear is changed to "3rd" in step S27. Step S26 is performed in step S1.
It is determined whether or not the next shift speed set in step 5 is O / D. Even in the cycle after the next shift speed is changed from O / D to 3rd in step S27, the determination in step S26 is Y.
ES.

In step S29, it is determined whether or not the time counted by the timer Ta is equal to or longer than the shift timing time T1. Step S20 and subsequent steps are repeated until the shift timing time T1 is reached. When the shift timing time T1 is reached, step S30 is executed, and the solenoids S1 and S1 are executed.
By switching between excitation and non-excitation of S2 and S3, the gear position of the automatic transmission 78 is switched to the next gear position set in step S15 or S43 or the 3rd gear position changed in step S27. After that, the flag F1 is set to "0" in step S31, the flag F4 is set to "0", and the timer Ta is reset in step S32. This timer Ta determines whether the upshift has been made and the flag F1 has been set to "1", or the timer Ta has been downshifted to increase the engine braking force and the flag F4 has been set to "1". It measures time.

Here, in step S6, O / D
Even if an upshift to the gear position is determined, step S
Until the gear is actually switched at 30,
That is, the shift timing time T after the shift is determined.
If all of the conditions of steps S21 to S26 including the accelerator OFF are satisfied before the time 1 has elapsed, the next shift speed is changed to 3rd. When the driver releases the accelerator, the actual shift to the O / D shift stage is prevented even if an upshift shift decision is made with a decrease in the accelerator operation amount Ac, and the O / D shift stage is prevented. The reduction of the engine braking force due to the shift to へ is satisfactorily avoided. For example, when the driver releases the accelerator in the state of point A in FIG.
Since the accelerator operation amount Ac crosses the “→ 3” upshift line and the “3 → O / D” upshift line, the shift is finally determined from 2nd to O / D in step S6 in step S6. In step S15, the O / D shift speed is set as the next shift speed. However, if the accelerator operation amount Ac becomes zero before the shift timing time T1 elapses after the “2 → 3” upshift is determined, "3 → O /
Even if the next gear shifts to O / D after crossing the "D" upshift line, the next gear is changed to 3rd in step S27, so that the gear is not upshifted to the O / D gear.

Even if the accelerator is turned off once,
If the depressing operation is performed again before the shift timing time T1 is reached, the determination in step S25 is NO, and the next shift speed is set to the O / D set in step S15 in step S28. When the vehicle is depressed, since the driver does not need so much engine braking force, the driver may upshift to the O / D gear position. The determination of step S29 is inserted between steps S20 and S21, and the determination of step S21 and subsequent steps are executed based on the driving state after the shift timing time T1 has elapsed, so that the shift speed is switched. good.

Also, the accelerator return speed is relatively slow,
Even when the accelerator is not turned off within the shift timing time T1, the shift is performed as set in step S15, but also in this case, since the driver does not need so much engine braking force, the O / There is no problem in upshifting to the D gear. In other words,
When the driver needs the engine braking force, the accelerator pedal may be quickly released, and when the driver desires coasting or the like that does not require much engine braking force, the accelerator pedal may be released slowly. It is good.

Next, the throttle control in FIGS. 7 to 9 will be described. First, in steps SS1 to SS5 in FIG. 7, the shift range, the running pattern, the vehicle speed V, and the accelerator operation amount Ac are the same as those in steps S21 to S25. When the judgment is made and all the conditions are satisfied, the automatic engine brake control in step SS8 and thereafter is executed.
If any one is NO, step SS6 in FIG.
In step F3, the flag F3 is set to "0"
Is set to "0", and normal throttle control is performed in step SS7. In the normal throttle control in step SS7, the accelerator operation amount A indicated by the accelerator operation amount signal SAc
c, a throttle valve opening TA (Ac) is obtained from a predetermined map or an arithmetic expression, the throttle valve opening TA (Ac) is set to a target throttle valve opening TA ^* , and the target throttle valve opening TA ^* is set. A throttle command signal SQ indicating the valve opening TA ^* is output to the throttle control computer 35. Throttle control computer 3
5 indicates the actual throttle opening θ of the throttle valve 20 by feedback control or the like.
Q indicates the target throttle valve opening degree TA ^* , that is, TA
(Ac) so that the throttle control signal DT
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”.
Is set to “0” in step SS6, and is “0” when step SS8 is first executed,
Subsequently, step SS10 is executed, and the vehicle speed V at that time is set to the target vehicle speed Vm. Since the flag F3 is set to “1” in step SS14 or SS19 in FIG. 8,
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 is compared with the vehicle speed V at that time.
If (Vm-Vf), step SS11 and subsequent steps in FIG. 8 are executed, but if V ≦ (Vm-Vf), step SS10 is executed again, and the target vehicle speed Vm is changed to the current vehicle speed V. Execute SS11 and below. The constant value Vf is determined by considering the change in the vehicle speed V due to the feedback control of the throttle valve opening θ in steps R2 and R4 in FIG. However, if the vehicle speed V is relatively greatly reduced by the operation of depressing the brake, the determination in step SS9 is NO, and the target vehicle speed Vm is changed in step SS10.

In step SS11 of FIG. 8, it is determined whether or not the brake is depressed based on the brake signal SB. If the brake is off, that is, if the depressing operation is not performed, steps SS12 and subsequent steps are executed. If the user steps on the brake to further decelerate, the determination in step SS11 is NO, and steps SS22 and SS23 are executed. Step SS2
In step 2, the target throttle valve opening TA ^{* is set} to 0 in order to increase the engine braking force, and a throttle command signal SQ indicating 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 subsequent steps in FIG. 5 are executed. At the beginning of the automatic engine brake control, that is, in the first cycle in which the accelerator is turned off, the normal brake is turned off.
The determination of step 1 is YES, and step SS14 or SS
At step 19, the flag F3 is set to "1", and in FIG. 5, each step of the engine braking after step S41 is executed.

Step SS executed when brake is off
In step 12, the flag F5 is set to "0", and in step SS13, it is determined whether or not the flag F1 is "1".
At 6, it is determined whether or not an upshift has been determined. If the flag F1 = 1, the flag F3 is set to "1" in step SS14, and then in step SS15, the same normal throttle control as in step SS7 is performed. When the upshift shift determination is not made, or when the upshift shift output is made and the flag F1 is set to “0” in step S31 of FIG. 6, the determination in step SS13 is NO. In step SS16, it is determined whether the flag F6 is "0". The flag F6 is set to “1” in step R8 in FIG. 9 when downshifting is performed to increase the engine braking force. When the flag F6 = 0, the flag F3 is already set to “1” in step SS17. 1 "is determined.

If the flag F3 is not "1" in the first cycle of the automatic engine brake control and the determination in step SS17 is NO, the flag F3 is set to "1" in step SS19, and then step SS20 is executed. The same normal throttle control as in step SS7 is performed.
When the flag F3 = 1, it is determined in step SS18 whether or not the gear is being shifted, for example, by whether or not the following equation (1) is satisfied. That is, the gear shift output is made in step S30 of FIG.
2, S3 excitation and de-energized is switched began slippage in the clutch C and brake B of the automatic transmission 78, after the rotation speed ratio of the turbine speed N _T and the output shaft rotation speed N _O is shifting, i.e. for shifting by substantially coincides with the gear ratio i of the current speed after the shift output ends, the rotational speed N _T of it such as, N _O, and the speed ratio i of the current gear stage
Is not shifting when the following formula (1) is satisfied, and is shifting when the following formula (1) is not satisfied. Then, if the determination in step SS18 is YES, that is, if the gear is not being shifted, the automatic engine brake throttle processing routine of step SS21 is executed, but if the gear is being shifted, step SS20 is executed. The above equation (1), the rotational speed N _T, taking into account the detection error of N _O are determined so as to satisfy with a predetermined width. Also, during a downshift to increase the engine braking force,
Since step SS24 and subsequent steps are executed subsequent to step SS16, it is determined in step SS18 whether or not the shift is substantially during the upshift.

[0036]

N _T ＮN _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 feedback control of the throttle valve opening θ is performed 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 or not the actual throttle valve opening θ represented by the throttle valve opening signal Sθ is smaller than a predetermined determination 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. If θ ≧ θ1, that is, if 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 in accordance with an arithmetic expression of feedback control.

In the next step R3, based on the current gear position and the target vehicle speed Vm, the throttle valve opening capable of maintaining the target vehicle speed Vm when traveling on flat ground, that is, the driving force in consideration of the running resistance becomes zero. Throttle valve opening TAm
(%) Is calculated by map interpolation from a data map stored in advance 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 shown in FIG. 11 is obtained by calculating the throttle valve opening at which the driving force matches the running resistance for each gear position and vehicle speed based on the experimentally obtained data as shown in FIG. . FIG.
Data indicates that the shift speed of the automatic transmission 78 is O / D in a vehicle equipped with an engine having the output characteristics shown in FIG.
(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. Since the throttle valve opening (angle) at point B, which coincides with the running resistance on the ground, is approximately 7.4 °, when this is converted to% with respect to 80 ° of full opening,
(7.4 / 80) × 100 = 9.3. That is,
In the data map of FIG. 11, the vehicle speed 8
The throttle valve opening TA _{45 at} 0 km / h is specifically 9.3%, and thus the throttle valve openings TA _{41 to} TA ₄₇ for each vehicle speed at the O / D shift stage are obtained. ing. Regarding the 3rd gear and the 2nd gear and the 1st gear where the engine brake operates, the above O /
The throttle valve opening TA ₃₁ to
_{TA 37, TA 21 ~TA 27,} TA 11 ~TA 17 is required. As is clear from the data in FIG. 12, the throttle valve opening TAm increases as the vehicle speed increases, and increases at lower speeds with a higher gear ratio at the same vehicle speed.

If TA1 <TAm, the throttle valve opening TA1 is set to the target throttle valve opening TA ^* in step R4, and the target throttle valve opening T ^* is set.
By outputting a throttle command signal SQ representing A ^* to the throttle control computer 35, the actual throttle valve opening θ of the throttle valve 20 becomes equal to the throttle valve opening T.
A1 is controlled. These steps R2, R
The throttle valve opening θ is quickly controlled so that the vehicle speed V substantially matches the target vehicle speed Vm by repeatedly executing the steps 3 and R4, and the target vehicle speed Vm when the accelerator is OFF or the vehicle speed V due to the brake depression operation is reduced. As a result, the engine braking force at which the vehicle travels at the target vehicle speed Vm that has been changed is obtained. In this embodiment, the vehicle speed V is set to the target vehicle speed Vm.
The feedback control of the throttle valve opening θ is performed so as to substantially match the vehicle speed V regardless of the change in the road surface gradient.
The engine braking force is increased or decreased so as to substantially match the target vehicle speed Vm, and when the gradient changes from a steep gradient to a gentle gradient, the vehicle speed V is prevented from being reduced against the driver's intention due to excessive application of the engine brake. You.

On the other hand, if TA1≥TAm, the determination in step R3 is NO, and in step R5, the throttle valve opening TAm is set to the target throttle valve opening TA ^* , and the target throttle valve opening TA ^* is expressed. By outputting the throttle command signal SQ to the throttle control computer 35, the throttle valve 20 is controlled so that the actual throttle valve opening θ becomes the throttle valve opening TAm. This is because the engine braking force is increased or decreased so that the vehicle speed V substantially matches the target vehicle speed Vm irrespective of the change in the road surface gradient as described above. Is opened and the vehicle speed V is maintained at the target vehicle speed Vm. However, in such an engine brake control, it is normal that the driver thinks that the vehicle speed V decreases on an uphill, 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 feedback control. As a result, the target vehicle speed Vm is maintained on a downhill or a flat ground, but on an uphill, the vehicle speed V becomes lower than the target vehicle speed Vm in accordance with the gradient, and the driving 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 above throttle control, the determination in step R1 becomes YES, and step R6 and subsequent steps are executed. At step R6, it is determined whether or not the current vehicle speed V is higher than the target vehicle speed Vm.
In the case of V ≦ Vm, that is, when the engine is decelerated by the engine braking effect due to the full closing of the throttle valve 20, there is no need to perform a downshift. Therefore, in the subsequent step R7, the target throttle valve opening TA ^{* is set} to 0. , The throttle valve 20 is kept fully closed. Step R8
Then, the flag F4 for instructing a downshift 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 in FIG. 5 is executed, and when the flag F6 is set to "1", steps SS24 and subsequent steps in FIG. 8 are executed. .

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

In the following step R10, a 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 transmission is output in step S30 to when the throttle valve 20 is opened and controlled, and the high speed side released during the downshift. The current engine speed NE and A / T oil temperature THO are set in advance by experiments and simulations so that the engine speed NE increases in accordance with the timing at which the clutch C and the brake B begin 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 is, the lower the viscosity resistance of the hydraulic oil is, the shorter the time required for draining and applying is, and, after the shift output is performed, the higher the clutch C and the brake B on the high-speed side. Since the delay time before the start of slipping becomes shorter, the throttle valve opening change timing time T2 becomes smaller as the A / T oil temperature THO becomes higher. In addition, the higher the engine speed NE, the longer the delay time between opening the throttle valve 20 and controlling the opening of the engine 10 and the actual blowing of the engine 10 becomes longer. Therefore, the throttle valve opening change timing time T2 increases as the engine speed NE increases. It will be a small value.

When the flag F6 is set to "1" in step R8, in the subsequent cycle, the process proceeds to step SS1 in FIG.
The determination at 6 is NO, and step SS24 is executed.
In step SS24, a shift output for downshift is made in step S30, and the next step S30 is executed.
In step 31, it is determined whether or not the flag F4 is set to "0". Until F4 = 0, the timer Tb is reset in step SS25.
Perform steps 26 and below. By resetting the timer Tb in step SS25, the timer Tb measures the elapsed time from when the flag F4 is set to “0”, in other words, when the downshift transmission output is performed, In step SS26, the content of the time measured by the timer Tb is equal to the throttle valve opening change timing time T.
It is determined whether or not two or more. And the timer Tb
When the measured time reaches the change timing time T2, the throttle valve opening TA2 is set to the target throttle valve opening TA ^* in step SS27, and the throttle command signal SQ representing the target throttle valve opening TA ^* is used for throttle control. The output to the computer 35 is controlled so that the actual throttle valve opening θ of the throttle valve 20 becomes the throttle valve opening TA2. In the next step SS28, based on the gear ratio i of the current gear stage and the rotational speeds N _T and N _O after the down-shift output is performed, whether the shift has been completed from the equation (1) or not. It is determined whether or not the shift is completed, and when the shift is completed, the flag F6 is set to "0" in step SS29. As a result, in the subsequent cycle, step SS17 and subsequent steps are executed following step SS16.

As described above, in this embodiment, when the downshift is performed in the accelerator OFF state in order to increase the engine braking force, the driving force after the downshift is equal to or slightly smaller than the driving force before the downshift. Since the throttle valve 20 is controlled to open to the throttle valve opening degree TA2, substantially the same engine braking force as before downshifting is applied even after downshifting, and shock due to a sudden increase in engine braking force is reduced. Being improved ride comfort. In particular, in the present embodiment, the steps after step R2 are performed after the downshift, so that
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 such as an excessive engine braking force due to a downshift and an accelerator operation is required, and the driving operation is 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 released by the downshift start slipping.
Since the timing at which the throttle valve 20 is opened and controlled is determined so that E increases, even during the shift process in which the engagement switching of the clutch C and the brake B is performed, the temporary stop due to the inertia torque of the engine 10 or the like. In addition to suppressing the increase in braking force, the engine rotational speed NE is quickly increased in combination with the transmission of torque from the drive wheels, and the shift time is shortened, so that the life of the friction materials of the clutch C and the brake B is improved. I do.

FIG. 16 shows a vehicle speed of 55 km / h on a downhill of 8% by the automatic engine brake control of this embodiment.
5 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 gear to the 2nd gear at the time of the gear shift, that is, the friction engagement device (clutch C ₂ ) Is about 0.69 sec from when the slip begins to occur until the friction engagement device (brake B ₁ ) on the low-speed side fully engages.

The line hydraulic pressure of the hydraulic control circuit 150 is generally controlled in accordance with the throttle valve opening θ. When the throttle valve 20 is controlled to open as described above, the line hydraulic pressure is increased. Accordingly, the engagement hydraulic pressure of the clutch C and the brake B is also increased, so that the clutch C and the brake B on the low speed side are rapidly and completely engaged, so that the shift time is further shortened. However, in this case, since a large shift shock is likely to occur, in this embodiment, at the time of opening control of the throttle valve 20 in step SS27, the line oil pressure is controlled to a low oil pressure when the throttle valve 20 is fully closed. ing.

In the present embodiment, the part for executing steps R9, R10, SS26, SS27 and SS28 in 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. Is composed.

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

For example, in the above-described embodiment, the automatic engine brake control has been described. However, when the accelerator is substantially OFF, the driver turns off the overdrive switch or switches the shift lever from the D range to the S range and the L range. The present invention is similarly applied to a case where a downshift is performed by performing the above operation. In such a case, a shock at the time of shifting due to a rapid change in the engine braking force is reduced by increasing the engine output. After the shift is completed, it is desirable that the throttle valve 20 be gradually closed so that the engine braking force increases smoothly.

In the above embodiment, the engine output is increased by controlling the opening of the throttle valve 20. However, an engine accessory such as an alternator is used, or the idle speed control valve 38 is opened and controlled. To increase the engine output.

In the above embodiment, the throttle valve opening θ
Has been described for a vehicle controlled by the throttle control computer 35, but the present invention is also applicable to a vehicle in which the throttle valve 20 is mechanically connected to an accelerator pedal and opened and closed. The configuration of the automatic transmission 78 and the number of shift stages can also be changed as appropriate.

In the above-described embodiment, the throttle valve opening TA2 is set based on the type of shift and the vehicle speed V. However, the throttle valve opening TA2 is set according to the operating state of the EGR (exhaust gas recirculation device) and the engine coolant temperature. The engine output changes due to the change in the engine friction torque. The change in the oil pump drive torque due to the A / T oil temperature THO, the change in the friction torque of the torque converter 110 and the input shaft 120, the change in the drive torque of auxiliary equipment such as an air conditioner and an alternator, etc. Even if the throttle valve opening θ is the same, the torque required for rotating and blowing up the input shaft 120 changes.
May be set.

In the above-described embodiment, the throttle valve opening change timing time T2 is determined so that the engine speed NE increases almost at the same time as the friction engagement device on the high speed side released during the downshift starts slipping. However, it is sufficient that the engine output is increased at least from the start of the slip to the time of complete engagement of the friction engagement device on the low speed stage. It is sufficient that the control for increasing the engine output is performed so that the driving force before and after the shift is substantially equal at the time of complete engagement, that is, at the completion of the shift. For example, in the initial stage of the shift when the friction engagement device on the high speed stage starts to slip, a predetermined value ΔTA is added to the throttle valve opening TA2 to take into account the 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 to temporarily open the throttle valve 20 until the engine speed increases.

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

In the above-described embodiment, the automatic engine brake control in step SS8 and subsequent steps is executed on condition that the automatic engine brake pattern is selected by the pattern select switch 70. Automatic engine brake control when the driving pattern is selected,
Automatic engine brake control may be executed regardless of the type of travel pattern. Of course, a switch for engine brake control can be provided independently of the pattern select switch 70.

Further, in the above-described embodiment, the vehicle speed limitation in steps SS3 and SS4 is provided as a condition for performing the automatic engine brake control. However, such a vehicle speed limitation is not necessarily essential, and the range of the vehicle speed limitation is appropriately determined. Another condition may be added as a condition for performing the automatic engine brake control.

Further, in the above-described embodiment, every time the determination in step SS9 becomes NO with the decrease in the vehicle speed V, step SS
10, the target vehicle speed Vm is sequentially changed according to the vehicle speed V at that time.
S9 may be omitted, and the target vehicle speed Vm may be changed according to the vehicle speed V when the brake is released, or the target vehicle speed Vm may be sequentially updated based on the vehicle speed V when the brake is turned on.

In the above-described 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, but in step S27 the next gear is returned. Is changed to 3rd, step S30 may be executed immediately before the shift timing time T1 is reached to output the shift.

In the above-described embodiment, the vehicle speed V when the accelerator is turned off or the brake is released is set to the target vehicle speed Vm. However, the target vehicle speed Vm does not need to completely match the vehicle speed V. 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 an error or the like.

In the above embodiment, the vehicle speed V is set to the target vehicle speed V.
m, the throttle valve opening θ is feedback-controlled so that the throttle valve opening θ is increased or decreased by a predetermined constant amount ΔTA, or the vehicle speed V
It is also possible to use another control method such as reducing the throttle valve opening θ by a fixed amount ΔTA so that the vehicle speed does not exceed the target vehicle speed Vm. Step S
The constant value Vf in S9 is determined in consideration of the fluctuation 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 brake controls, such as performing a downshift so that the acceleration becomes negative and increasing the engine brake force.

In the above-described embodiment, the engine control computer 32, the transmission control computer 34, and the throttle control computer 35 are formed separately, but they may be formed by a single computer. It is possible.

Although not specifically exemplified, the present invention can be embodied with various modifications and improvements based on the knowledge of those skilled in the art.

[Brief description of the drawings]

FIG. 1 is a diagram corresponding to claims 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 according to an embodiment of the present invention.

FIG. 3 is a diagram illustrating a configuration of the automatic transmission of FIG. 2;

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

FIG. 5 is a flowchart illustrating an operation of a shift determination of whether or not to change the gear position of the automatic transmission of FIG. 2;

FIG. 6 is a flowchart illustrating an operation of a shift control for switching a shift speed of the automatic transmission of FIG. 2;

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

8 is a flowchart illustrating an operation of controlling the throttle valve opening of the engine in FIG. 2 in conjunction with FIG. 7;

FIG. 9 is a flowchart illustrating the contents of an automatic engine brake throttle processing routine of FIG. 8;

FIG. 10 is an example of a shift map for switching a shift speed of the automatic transmission of FIG. 2;

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

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

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

FIG. 14 is an example of a data map used for obtaining a throttle valve opening TA2 in step R9 of FIG. 9;

FIG. 15 is an example of a data map used for obtaining a throttle valve opening degree change timing time T2 in step R10 of FIG. 9;

FIG. 16 is a diagram showing the embodiment of FIG.
6 is a time chart showing changes in the rotation speed, drive torque, and the like of each unit when a downshift is performed to a shift stage d.

[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

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-3-22932 (JP, A) JP-A-63-284039 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B60K 41/04 F02D 29/00 F02D 41/04 F16H 61/00

Claims (1)

(57) [Claims] When an automatic transmission is downshifted to a low gear where an engine braking force acts with an accelerator substantially in an OFF state, at least when the downshift is completed, a driving force before the downshift and a driving force after the downshift are provided. An engine braking force control device comprising an engine output increasing means for increasing the engine output so that the force becomes substantially equal.