Control of the supply pressure of a hydraulic actuator

• US 4,633,985 A
• Filed: 03/22/1984
• Issued: 01/06/1987
• Est. Priority Date: 03/22/1983
• Status: Expired due to Term

• Current Assignee: Regie Nationale Des Usines Renault
• Original Assignee: Regie Nationale Des Usines Renault
• Inventors: Leorat, Francois
• Primary Examiner(s): Dorner, Kenneth J.
• Assistant Examiner(s): Diehl, Dwight G.
• Application Number:
  US06/592,294
• Time in Patent Office: 1,020 Days
• Field of Search: 192/0.032, 192/0.033, 192/0.055, 192/0.076, 192/0.094, 192/0.096, 192/3.31, 192/3.58, 192/103 R, 74/866, 74/867
• US Class Current: 477/138
• CPC Class Codes: B60W 2050/0022 Gains, weighting coefficients or weighting functions
• CPC Class Codes: F16D 2500/1026 Hydraulic
• CPC Class Codes: F16D 2500/10412 Transmission line of a vehicle
• CPC Class Codes: F16D 2500/1068 Engine supercharger or turbocharger
• CPC Class Codes: F16D 2500/1085 Automatic transmission
• CPC Class Codes: F16D 2500/3067 Speed of the engine
• CPC Class Codes: F16D 2500/3108 Vehicle speed
• CPC Class Codes: F16D 2500/3111 Standing still, i.e. signal detecting when the vehicle is standing still or bellow a certain limit speed
• CPC Class Codes: F16D 2500/3166 Detection of an elapsed period of time
• CPC Class Codes: F16D 2500/70217 Pressure
• CPC Class Codes: F16D 2500/70235 Displacement
• CPC Class Codes: F16D 2500/70406 Pressure
• CPC Class Codes: F16D 2500/7041 Position
• CPC Class Codes: F16D 2500/70418 Current
• CPC Class Codes: F16D 2500/70605 Adaptive correction; Modifying control system parameters, e.g. gains, constants, look-up tables
• CPC Class Codes: F16D 2500/70668 Signal filtering
• CPC Class Codes: F16D 2500/7101 Driver alarm
• CPC Class Codes: F16D 48/06 Control by electric or electronic means, e.g. of fluid pressure
• CPC Class Codes: F16D 48/066 Control of fluid pressure, e.g. using an accumulator F16D48/062, F16D48/068 take precedence
• CPC Class Codes: F16H 2059/467 of torque converter
• CPC Class Codes: F16H 2312/02 : Driving off
• CPC Class Codes: F16H 59/24 : dependent on the throttle opening
• CPC Class Codes: F16H 59/44 : dependent on machine speed of the machine, e.g. the vehicle
• CPC Class Codes: F16H 61/0021 : Generation or control of line pressure
• CPC Class Codes: F16H 61/20 : Preventing gear creeping ; Transmission control during standstill, e.g. hill hold control

Abstract

A device for controlling the supply pressure of a hydraulic actuator for an automatic transmission of an automobile. A pressure modulator varies the hydraulic pressure depending on the output of a controller. The controller receives input information on engine speed, turbine speed, engine load and vehicle speed. The transmission is controlled to be disengaged when the automobile is stopped, and reengaged smoothly.

Claims

1. A control device for controlling the hydraulic pressure of a hydraulic actuator of a transmission, said actuator including a cylinder and mating linings, comprising:

a controller for producing a control signal having a first input for receiving an engine speed signal ω

_m, a second input for receiving a turbine speed signal ω

_t, a third input for receiving an engine load signal α

_C, a fourth input for receiving a vehicle speed signal V_v, a fifth input for receiving an enabling input E, and an output for transmitting said control signal;

a pressure modulator connected to said output of said controller, said modulator being controlled by said control signal and closed by a lack of current on said output of said controller;

said control signal being a function of the measurement of the slippage Δ

ω

=ω

_m -ω

_t when α

_C and V_v are less than preset threshold values, said control signal causing said pressure modulator to position said cylinder so that said linings mate;

said controller including a first comparator and a second comparator, said first comparator comparing Δ

ω

to a first threshold δ

ω and

said second comparator comparing Δ

ω

to a second threshold ε

,

whereby a large gain correction signal δ

=δ

(Δ

ω

₁) is generated to modify said control signal if Δ

ω

₁ =δ

ω

-Δ

ω

is negative, a small gain correction signal δ

=δ

(Δ

ω

₂) is generated if Δ

ω

₁ is positive and Δ

ω

₂ =ε

-Δ

ω

is negative, and a zero gain correction signal is generated if Δ

ω

₁ and Δ

ω

₂ are positive.

2. A control device according to claim 1

wherein said controller further comprises an alarm, a timing means for producing a time signal t indicative of the length of time said actuator has been actuated and a third comparator for comparing with a maximum time t_max ;

whereby if t>

t_max ;

if Δ

ω

>

δ

ω

, said alarm is actuated and full pressure is supplied,

if ε

<

Δ

ω

<

δ

ω

, said control signal is modified to a third threshold δ

ω

₁ where ε

<

δ

ω

₁ <

δ

ω

;

if Δ

ω

>

δ

ω

₁, said alarm is actuated and full pressure is supplied

if Δ

ω

<

δ

ω

₁, Δ

ω

becomes the new threshold and t becomes zero.

3. A control device according to claim 1 wherein a return to full supply pressure is made according to a predetermined time function.