JPH06346954A - Engine brake controller of automatic transmission - Google Patents

Abstract

PURPOSE:To obtain such driving performance as desired by a driver according to a turning state or an advancing state when a vehicle climbs a slope by clamping a clutch for engine brake if the vehicle is in its turning state, or by applying engine brake control for releasing the clutch if the vehicle is not in its turning state, when the vehicle is in its coast driving state. CONSTITUTION:When a vehicle is in its coast driving state on a slope, a clutch (e) for engine brake provided in parallel with a forward one-way clutch (d) is clampled if the vehicle is in its turning state, the reverse driving force from a driving wheel (c) is transmitted to an engine (b) side through the clutch (e), and the engine brake acts, thereby sufficient acceleration response by depression of an accelerator pedal can be obtained. Moreover, if the vehicle is in the advancing state in the similar driving, the clutch (e) for engine brake provided in parallel with the forward one-way clutch (d) is released, and the forward one-way clutch (d) is slips, the engine caused by the engine brake action can be prevented when the foot is separated from the accelerator pedal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine brake control device for an automatic transmission, in which an engine clutch is provided in parallel with a forward one-way clutch for suppressing shift shock during downshifting.

[0002]

2. Description of the Related Art Conventionally, as an engine brake control device for an automatic transmission, for example, one described in "Nissan Full Range E-AT Maintenance Manual" (issued by Nissan Motor Co., Ltd.) is known.

The automatic transmission described in the above-mentioned conventional sources employs a forward one-way clutch in order to suppress a shift shock at the time of downshifting. This forward one-way clutch is used to drive the driving force from the engine. Although it is transmitted to the wheels, the reverse driving force from the rear wheels is not transmitted to the engine due to idling. Therefore, when the vehicle is coasting or when the engine brake is required for the select operation from the D range to the second speed fixed range or the first speed fixed range, the engine brake does not work. Accordingly, an overrun clutch provided in parallel with the forward one-way clutch, gear position D ₁ speed, D ₂ speed, with D ₃ speed, such as when coasting running state of the throttle opening is set opening less, required engine brake Engine brake control is sometimes disclosed that engages an overrun clutch.

On the other hand, as a conventional technique for prohibiting an upshift when the road gradient is large, for example, Japanese Patent Laid-Open No. 62-20 is known.
The device described in Japanese Patent Publication No. 0065 is known, and as a conventional technique for selecting a shift schedule whose shift point is on the high speed side from a plurality of set shift schedules when the road gradient is large, for example, Japanese Patent Laid-Open No. 2-30055
The device described in Japanese Patent No. 8 is known.

[0005]

However, in the latter road gradient-corresponding shift control, when the road gradient is large, the gear position is lower than in the normal gear shift control. When combined with the engine brake control of No. 1, there is a problem that the driving performance intended by the driver cannot be obtained in the coasting operation state on an uphill road.

[0006] For example, when the accelerator is returned on an uphill slope on a long straight road, the vehicle speed will drop too much due to the braking action if the engine is in a brake state in which the overrun clutch is engaged. Also, when the accelerator is returned on a curved uphill road, if the overrun clutch is released and the vehicle is in a free running state, a sufficient response cannot be obtained when the accelerator is depressed to accelerate next time.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an engine brake control device for an automatic transmission for controlling an embracing clutch provided in parallel with a forward one-way clutch. The purpose is to obtain the driving performance intended by the driver depending on whether the vehicle is in a turning state or a straight traveling state when the vehicle is climbing a slope.

[0008]

In order to achieve the above object, an engine brake control device for an automatic transmission according to the present invention comprises:
If the upshift is prohibited or the shift point is changed to the high speed side by the shift control corresponding to the running load and the vehicle is in the coasting state, the clutch for braking is engaged if the vehicle is turning, and if the vehicle is not turning It is a means for performing engine brake control that releases the clutch.

That is, as shown in the claim correspondence diagram of FIG. 1, a forward one-way clutch d which is provided in the power train a of the automatic transmission and operates in an accelerating state for transmitting the driving force from the engine b to the driving wheels c. , The forward one-way clutch d, which is provided in parallel, transmits the reverse driving force from the drive wheels c by engaging the forward one-way clutch d during idling, and an inclination detecting means f for detecting a road inclination. When the road gradient is large, the upshift is prohibited or the shift control means g for changing the shift point to the high speed side, the turning detection means h for detecting the turning state of the vehicle, and the coasting operation state Coasting operation detecting means i for detecting the speed change, and shift control means g corresponding to the traveling load.
When the upshift is prohibited or the shift point is changed to the high speed side by the, and the vehicle is in the coasting state, the emblem clutch e is engaged if the vehicle is in the turning state, and the emblem clutch e is not in the vehicle turning state. And an engine brake control means j for releasing the engine.

[0010]

When traveling on an uphill road, when the road gradient detected by the gradient detecting means f is large, the upshift is prohibited or the shift point is changed to the high speed side in the traveling load corresponding shift control means g. The shift control corresponding to the traveling load is performed.

When the coasting operation detecting means i detects that the vehicle is in the coasting operation state, the engine braking control means j makes
If the vehicle is in the turning state by the detection of the turning detection means h, the emblem clutch e is engaged, and if the vehicle is not in the turning state by the detection of the turning detection means h, the embracing clutch e is released.

Therefore, when the vehicle is in a turning state during coasting on an uphill road, the drive wheel c is engaged by engaging the embrace clutch e provided in parallel with the forward one-way clutch d. The reverse driving force from the engine is transmitted to the engine b side via the clutch for clutching e, the engine brake is applied, and a sufficient accelerator response is obtained during the subsequent acceleration operation by depressing the accelerator.

When the vehicle is in a straight traveling state during coasting on an uphill road, the embrace clutch e provided in parallel with the forward one-way clutch d is released, so that the forward one-way clutch is released. The idling of the clutch d does not act and the engine brake does not act, and a drop in vehicle speed due to the engine braking effect is prevented when the accelerator is released.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

First, the structure will be described.

FIG. 2 is an overall control system diagram showing an automatic transmission to which the engine brake control device of the present invention is applied.

In FIG. 2, 1 is an engine, 2 is a torque converter, 3 is a power train, 4 is a hydraulic control unit, 5a and 5b are shift solenoids, 6 is an overrun clutch solenoid, 7 is an A / T control unit, 8 Is a throttle opening sensor, 9 is a vehicle speed sensor, 10 is a lateral acceleration sensor, 11 is a turbine speed sensor, 12 is an engine speed sensor, and 13 is another sensor.
Switches.

The power train 3 has two planetary gear sets and transmission elements, as will be described later.
The fourth forward speed is achieved by controlling the operation of the speed change elements.

The hydraulic control unit 4 is composed of a plurality of valves for producing control hydraulic pressure to the hydraulically operated speed change elements of the power train 3.

The shift solenoids 5a and 5b are A /
By combining the ON and OFF commands from the T control unit 7, the first to fourth speed stages are obtained.

The overrun clutch solenoid 6
Engages an overrun clutch 44, which will be described later, in response to an ON command from the A / T control unit 7, and turns it OFF.
The overrun clutch 44 is released according to the command.

The A / T control unit 7 is an electronic control circuit which performs gear shift control, engine brake control, line pressure control, lockup control, etc. based on various input information.

The throttle opening sensor 8 detects the throttle opening Tvo.

The vehicle speed sensor 9 detects the vehicle speed Vsp by a rotation sensor provided on the transmission output shaft 14.

The lateral acceleration sensor 10 detects the lateral acceleration G acting on the vehicle body.

The turbine rotation speed sensor 11 detects the turbine rotation speed Nt by a rotation sensor provided on the transmission input shaft 15.

The engine speed sensor 12 detects the engine speed Ne by means of a rotation sensor provided on the crankshaft 16.

FIG. 3 is a diagram showing a torque converter and a power train.

In FIG. 3, 30 is an oil pump and 31
Is a brake band, 32 is a reverse clutch, 33 is a high clutch, 34 is a front sun gear, 35 is a front pinion, 36 is a front ring gear, 37 is a front carrier, 38 is a rear sun gear, 39 is a rear pinion,
40 is a rear ring gear, 41 is a rear carrier, 42 is a forward clutch, 43 is a forward one-way clutch (corresponding to a forward one-way clutch d), 44 is an overrun clutch (corresponding to an embracing clutch e), 4
5 is a low one-way clutch, 46 is a low & reverse brake, 47 is a parking pole, and 48 is a parking gear.

FIG. 4 is a diagram showing an upshift schedule set in the memory circuit of the A / T control unit 7. In this upshift schedule, normal shift points for achieving optimum drivability when traveling on a flat road. (solid line)
And a shift point for climbing (dotted line) that shifts the normal shift point to the high vehicle speed side so that downshifting is easy when climbing and difficult to upshift to obtain optimum drivability.
Two shift points are set.

Next, the operation will be described.

[Engine Brake Control Operation] FIG. 5 is a flow chart showing the flow of engine brake control operation processing performed by the A / T control unit 7, and each step will be described below.

In step 50, the engine speed Ne
, Turbine rotation speed Nt, vehicle speed Vsp, throttle opening Tvo, and lateral acceleration G are input.

In step 51, the climbing condition (gradient sine value sin θ) is calculated (corresponding to the gradient detecting means f).

The calculation of the climbing state is expressed by the formula of driving force = acceleration resistance + rolling resistance + aerodynamic resistance + gradient resistance, and is replaced by gradient resistance = sin θ, as shown in FIG.
It is calculated by the flowchart shown in.

In step 52, the turning state (lateral acceleration integrated value G2) is calculated (corresponding to the turning detection means h).

This turning state is calculated according to the flowchart shown in FIG. 7 using the current and past absolute lateral acceleration values | G | so that the meandering turning state can be detected.

At step 53, it is judged whether the vehicle is climbing uphill or not depending on whether the gradient sine value sin θ is equal to or more than a set value.

In step 54, if the determination in step 53 is NO, the shift control based on the normal shift point is performed.

In step 55, normal engine brake control is performed.

At step 56, other processing (lock-up control, etc.) is performed.

In step 57, when the determination in step 53 is Yes, shift control is performed by the uphill shift point (corresponding to the shift control means g corresponding to the running load).

In step 58, it is judged whether or not the vehicle is coasting according to whether or not the throttle opening Tvo is equal to or smaller than a set value (corresponding to coasting detection means i).

In step 59, it is judged whether or not the vehicle is in a turning state depending on whether or not the lateral acceleration integrated value G2 is equal to or more than a set value.

In step 60, if the determination in step 59 is No, a control command for releasing the overrun clutch 44 (O to the overrun clutch solenoid 6 is issued).
FF command) is output.

In step 61, if the determination in step 59 is Yes, a control command for engaging the overrun clutch 44 (ON command to the overrun clutch solenoid 6) is output.

The steps 58 to 61 correspond to the engine brake control means j in the claims.

[Slope sine value calculation processing] FIG. 6 is a flowchart showing the flow of the gradient sine value calculation processing operation. Each step will be described below.

In step 51a, the output shaft torque To of the automatic transmission is predicted.

The output shaft torque To is predicted by detecting the turbine torque by sensor detection and various calculations, and by calculating from the turbine torque, the gear ratio of the automatic transmission, the transmission efficiency and the like. Alternatively, the torque sensor may be used for direct detection.

In step 51b, the gradient sine value sin θ
Is calculated by the following formula.

Sin θ = K1 * {(To −K2 * Vsp
² ) + K3 * Vsp} -ΔVsp where K1, K2, K3; coefficient, Vsp; vehicle speed, ΔVs
p: A value obtained by converting the gradient resistance into a vehicle speed.

[Lateral Acceleration Integrated Value Calculation Processing] FIG. 7 is a flowchart showing the flow of the lateral acceleration integrated value calculation processing operation. Each step will be described below.

At step 52a, the lateral acceleration integrated value G2
Is calculated by the following formula.

G2 = | G | + K4 * | G (-1) | + K5 *
| G (-2) | + K6 * | G (-3) | where K4, K5, K6; coefficients, | G | is the absolute value of the current lateral acceleration, and | G (-1) | is one control cycle before. Lateral acceleration absolute value, | G (-2) | is the lateral acceleration absolute value two control cycles before, | G
(-3) | is the absolute value of lateral acceleration three control cycles before.

At step 52b, the lateral acceleration G this time is taken as the lateral acceleration G (-1) one control cycle before, and the lateral acceleration G (-1) one control cycle before is the lateral acceleration G (two control cycles before. -2), the lateral acceleration G (-2) two control cycles before is the lateral acceleration G (-3) three control cycles before.

[When traveling on a flat road] When traveling on a flat road, as shown in FIG.
In the flowchart of step 50, step 51, step 52, step 53, step 54, step 5
The sequence is 5 → step 56. In step 54, shift control is performed at the normal shift point, and in step 55
Then, normal engine brake control is performed.

Here, the normal engine braking control is, for example, when coasting with the throttle opening less than the set opening and when the gear position is D range D ₁ , D ₂ and D ₃ speeds. Overrun clutch 44 at 2 ₁ speed, 2 ₂ speed of _2nd speed fixed range and at 1 ₁ speed, 1 ₂ speed of 1st speed fixed range
Is the control that is concluded.

Therefore, when traveling on a flat road, a shift with high drivability can be achieved by the shift control based on the normal shift point, and when the vehicle is coasting due to the accelerator pedal being released or from the D range to the second speed fixed. The effect of engine braking is ensured by engaging the overrun clutch 44 during a select operation to the range or fixed first speed range, that is, when engine braking is required.

[When going straight uphill] When going straight uphill, in the flowchart of FIG. 5, step 50 → step 51 → step 52 → step 53 → step 57 → step 58 →
The flow from step 59 to step 60 is executed. In step 57, shift control is performed by the uphill shift point, and in step 60, engine brake control for releasing the overrun clutch 44 is performed.

Therefore, at the time of going straight uphill, gearshift control is performed optimally for uphill climbing which is difficult to upshift and easy to downshift by gearshift control by the uphill shifting point.

By controlling the disengagement of the overrun clutch 44 in a state where the gear position is lower than usual by this shift control, engine braking is performed when the accelerator pedal is released on a long straight uphill road. The vehicle speed does not drop due to the action, and the traveling performance responding to the driver's request can be obtained.

In other words, if the control for engaging the overrun clutch 44 is performed when going straight uphill, the vehicle speed will drop too much due to unnecessary engine braking when the accelerator pedal is released.

[When turning uphill] When turning uphill, in the flowchart of FIG. 5, step 50 → step 51 → step 52 → step 53 → step 57 → step 58 →
The flow is from step 59 to step 61. In step 57, shift control is performed according to the uphill shift point, and in step 61, engine brake control for engaging the overrun clutch 44 is performed.

Therefore, at the time of turning uphill, the shift control is performed optimally for climbing which is difficult to upshift and easy to downshift by the shift control based on the uphill shift point.

By controlling the engagement of the overrun clutch 44 in the lower gear position than usual by this shift control, the accelerator pedal is released on the curved uphill road, and then the vehicle is accelerated. For this reason, when the accelerator is depressed, the acceleration operation is performed after the engine brake is applied, so that the change range of the driving force is large with respect to the accelerator operation, and a sufficient response as required by the driver can be obtained.

In other words, when the control for releasing the overrun clutch 44 is performed at the time of turning uphill, the accelerator pedal is released, and then, when the accelerator is depressed for acceleration, the engine is not braked and the engine is not running. The accelerator response requested by the driver cannot be obtained due to the accelerator operation from.

Next, the effect will be described.

(1) In the engine brake control device for an automatic transmission that controls the overrun clutch 44 provided in parallel with the forward-way clutch 43, the shift point is changed to the high speed side by the shift control corresponding to the running load, and When the vehicle is in the coasting operation state, if the vehicle is in the turning state, the overrun clutch 44 is engaged, and if it is not in the vehicle turning state, the engine brake control is performed to release the overrun clutch 44. The driving performance intended by the driver can be obtained depending on whether the vehicle is in a straight traveling state.

(2) Based on the expression of driving force = acceleration resistance + rolling resistance + aerodynamic resistance + gradient resistance, the gradient resistance is replaced with the gradient sine value sin θ, and the climbing state is detected by this gradient sine value sin θ. Because,
It is possible to accurately detect the traveling load due to the road gradient.

(3) Absolute value of lateral acceleration present and past | G |
The lateral acceleration integrated value G2
Since it is detected by the method described above, it is possible to accurately detect the turning state on the meandering curved road.

Although the embodiments have been described above with reference to the drawings, the specific configuration is not limited to the embodiments, and modifications and additions within the scope of the present invention are included in the present invention. Be done.

For example, in the embodiment, an example in which a shift schedule having a normal shift point and a climbing shift point is used as the shift control corresponding to the running load has been shown, but an upshift may be prohibited during climbing. Further, one shift schedule is provided, and the pseudo throttle opening or the pseudo vehicle speed is set in accordance with the gradient resistance, and the pseudo throttle opening or the pseudo vehicle speed is used for the gear position search. The shift control may be performed by an infinite number of virtual shift schedules.

[0074]

As described above, according to the present invention, in the engine brake control device of the automatic transmission for controlling the embrace clutch provided in parallel with the forward one-way clutch, the shift control corresponding to the traveling load is performed. Engine brake that engages the clutch for clutch when the vehicle is turning and releases the clutch for clutching when the vehicle is turning when the vehicle is turning when the upshift is prohibited or the shift point is changed to the high speed side and the vehicle is coasting. Since the control means is used, it is possible to obtain the effect that the driving performance intended by the driver can be obtained depending on whether the vehicle is in the turning state or the straight traveling state when the vehicle is climbing uphill.

[Brief description of drawings]

FIG. 1 is a claim correspondence diagram showing an engine brake control device for an automatic transmission according to the present invention.

FIG. 2 is an overall control system diagram showing an automatic transmission to which the engine brake control device of the embodiment is applied.

FIG. 3 is a diagram showing a torque converter and a power train of the automatic transmission according to the embodiment.

FIG. 4 is a diagram showing a shift schedule stored and set in an A / T control unit according to an embodiment.

FIG. 5 is a flowchart showing a flow of engine brake control processing operation performed by an A / T control unit of the embodiment apparatus.

FIG. 6 is a flowchart showing a flow of a gradient sine value calculation processing operation performed by the A / T control unit of the embodiment apparatus.

FIG. 7 is a flowchart showing a flow of lateral acceleration integrated value calculation processing operation performed by the A / T control unit of the embodiment apparatus.

[Explanation of symbols]

 a power train b engine c drive wheels d forward one-way clutch e emblem clutch f gradient detection means g traveling load compatible shift control means h turning detection means i coasting operation detection means j engine brake control means

Claims (1)

[Claims] 1. A forward one-way clutch, which is provided in a power train of an automatic transmission and operates in an accelerating state for transmitting a driving force from an engine to driving wheels, and a forward one-way clutch, which are provided in parallel to each other for forward travel. When the one-way clutch is idling, the clutch for embroidery that transmits the reverse driving force from the drive wheels when engaged, the slope detection means that detects the road gradient, and when the road gradient is large, prohibit upshifting or change the shift point to high speed. Shift control means for changing to a side, turning detection means for detecting the turning state of the vehicle, coasting operation detection means for detecting whether the vehicle is in a coasting operation state, and prohibition of upshifting by the shift control means for traveling load or When the speed change point is changed to the high speed side and the vehicle is in the coasting operation, if the vehicle is turning, engage the clutch for emblem. An engine brake control device for an automatic transmission, comprising: engine brake control means for releasing the engine clutch when the vehicle is not in a turning state.