Engine brake control system for automatic power transmission with variable response characteristics in shifting operational mode into engine braking range

• US 5,161,432 A
• Filed: 03/15/1991
• Issued: 11/10/1992
• Est. Priority Date: 02/15/1990
• Status: Expired due to Term

• Current Assignee: Transtechnology Ltd.
• Original Assignee: Jatco Limited (Nissan Motor Co., Ltd.)
• Inventors: Iizuka, Naonori, Matsumoto, Shigetsugu
• Primary Examiner(s): Lorence, Richard
• Assistant Examiner(s): TA, KHOI QUANG
• Application Number:
  US07/670,334
• Time in Patent Office: 606 Days
• Field of Search: 192/4 A, 364/424.1, 74/866, 74/861
• US Class Current: 477/119
• CPC Class Codes: B60W 2510/0638 Engine speed
• CPC Class Codes: B60W 2510/069 Engine braking signal
• CPC Class Codes: B60W 2540/16 Ratio selector position
• CPC Class Codes: F16H 59/14 Inputs being a function of torque or torque demand
• CPC Class Codes: F16H 59/44 dependent on machine speed of the machine, e.g. the vehicle
• CPC Class Codes: F16H 59/54 dependent on signals from the brakes, e.g. parking brakes
• CPC Class Codes: F16H 61/21 Providing engine brake control

Abstract

An engine brake control system generally engages an overrun clutch in overall throttle valve open angle range at operational ranges for effecting engine brake. The control system is responsive to variation of selected operational range from a high transmission speed ratio range for automatic speed ratio selection to the engine braking range for establishing engagement of the overrun clutch with a predetermined lag time. The predetermined lag time is adjusted depending upon the vehicle driving condition.

Claims

1. A control system for an automatic power transmission for an automotive vehicle, comprising:

a plurality of frictional elements selectively establishing a plurality of mutually distinct transmission speed ratios which include at least a first selectable speed ratio and a second selectable speed ratio, said frictional elements including an overrun clutch for delivery of negative driving torque from a final drive to an automotive internal combustion engine for deceleration of the latter;

a sensor means for monitoring a vehicle traveling condition for producing a second sensor signal indicative of a vehicle traveling condition;

means for manually entering a command for selection of a transmission speed ratio from among the plurality of speed ratios; and

a controller responsive to said transmission speed ratio selection command, for detecting a demand for engine braking, said controller discriminating a mutually distinct first mode of engine braking demand, in which said transmission speed ratio selection command is maintained at said first selectable speed ratio, and a second mode of engine braking demand, in which the transmission speed ratio selection command is the command for said first selectable speed ratio, said controller being responsive to said first mode of engine braking demand for instantly commanding engagement of said overrun clutch, and being responsive to said second mode of engine braking demand for deriving a delay time based on said second sensor signal, and commanding engagement of said overrun clutch after expiration of said delay time.

2. A control system for an automatic power transmission as set forth in claim 1, wherein said sensor means further comprises an engine speed demand sensor for monitoring a position of an engine speed control element which is coupled with a manually operable engine speed control means for detecting demand for an engine revolution speed and producing a first sensor signal indicative of the monitored engine speed demand, and said controller is responsive to said engine speed demand smaller than a predetermined criterion representative of about no demand for engine acceleration, for instantly commanding engagement of said overrun clutch.

3. A control system for an automatic power transmission as set forth in claim 2, wherein said engine speed demand sensor comprises a throttle angle sensor for monitoring a throttle valve angular position.

4. A control system for an automatic power transmission for an automotive vehicle, comprising:

a plurality of frictional elements selectively establishing a plurality of mutually distinct transmission speed ratios which include at least a first selectable transmission speed ratio and a second selectable transmission speed ratio, said frictional elements including an one-way clutch for exclusively permitting delivery of engine driving torque from an automotive internal combustion engine to a final drive, and an overrun clutch provided in a parallel relationship with said one-way clutch for exclusively delivering engine braking torque from a final drive to an automotive internal combustion engine for deceleration of the latter;

a sensor means for monitoring a vehicle traveling condition for producing a second sensor signal indicative of a vehicle traveling condition;

means for manually entering a command for selection of a transmission speed ratio from among the plurality of speed ratios;

a controller responsive to said transmission speed ratio selection command, for detecting a demand for engine braking, said controller discriminating a mutually distinct first mode of engine braking demand, in which said transmission speed ratio selection command is maintained at said first selectable speed ratio, and a second mode of engine braking demand, in which said transmission speed selection command is other than the command for said first, and selectable speed ratio to said second selectable speed ratio, said controller being responsive to said first mode of engine braking demand for instantly commanding engagement of said overrun clutch, and being responsive to said second mode of engine braking demand for deriving a delay time based on said second sensor signal, and commanding engagement of said overrun clutch after expiration of said delay time.

5. A control system for an automatic power transmission for an automotive vehicle, comprising:

a plurality of frictional elements selectively establishing a plurality of mutually distinct transmission speed ratios which include at least a first selectable speed ratio and a second, selectable speed ratio, said frictional elements including an overrun clutch for delivery of a negative driving torque from a final drive to an automotive internal combustion engine for deceleration of the latter;

a sensor means for monitoring a vehicle traveling condition for producing a second sensor signal indicative of a vehicle traveling condition, said sensor means including a vehicle speed sensor for monitoring a traveling speed to produce a vehicle speed indicative signal;

means for manually entering a command for selection of a transmission speed ratio among a plurality of speed ratios;

a controller responsive to said transmission speed ratio selection command, for detecting a demand for engine braking, said controller discriminating a mutually distinct first mode of engine braking demand, in which said transmission speed ratio selection command is maintained at said first selectable speed ratio, and a second mode of engine braking demand, in which the transmission speed ratio selection command is other than the command for said first selectable speed ratio, and to said second lower selectable speed ratio, said controller being responsive to said first mode of engine braking demand for instantly commanding engagement of said overrun clutch, and being responsive to said second mode of engine braking demand for deriving a delay time based on said vehicle speed indicative signal so that said delay time is increased according to an increase of said vehicle speed indicative signal value, and commanding engagement of said overrun clutch after expiration of said delay time.

6. A control system for an automatic power transmission for an automotive vehicle, comprising:

a plurality of frictional elements selectively establishing a plurality of mutually distinct transmission speed ratios which include at least a first selectable speed ratio and a second selectable transmission speed ratio, said frictional elements including a one-way clutch for exclusively permitting delivery of engine driving torque from an automotive internal combustion engine to a final drive, and an overrun clutch provided in a parallel relationship with said one-way clutch for exclusively delivery of engine braking torque from a final drive to an automotive internal combustion engine for deceleration of the latter;

a sensor means for monitoring a vehicle traveling condition for producing a second sensor signal indicative of a vehicle traveling condition, said sensor means including a vehicle speed sensor for monitoring a traveling speed to produce a vehicle speed indicative signal;

means for manually entering a command for selection of a transmission speed ratio among a plurality of speed ratios;

a controller responsive to said transmission speed ratio selection command, for detecting a demand for engine braking, said controller discriminating a mutually distinct first mode of engine braking demand, in which said transmission speed ratio selection command is maintained at said first selectable speed ratio, and second mode of engine braking demand, in which transmission speed ration selection command is the command for said first higher selectable speed ratio, and to said second lower selectable speed ratio, said controller being responsive to said first mode of engine braking demand for instantly commanding engagement of said overrun clutch, and being responsive to said second mode of engine braking demand for deriving a delay time based on said vehicle speed indicative signal so that said delay time is increased according to an increase of said vehicle speed indicative signal value, and commanding engagement of said overrun clutch after expiration of said delay time.

7. A control system for an automatic power transmission as set forth in claim 6, wherein said sensor means further comprises an engine speed demand sensor for monitoring a position of an engine speed control element which is coupled with a manually operable engine speed control means for detecting demand for an engine revolution speed and producing a first sensor signal indicative of the monitored engine speed demand, and said controller is responsive to said engine speed demand smaller than a predetermined criterion representative of about no demand for engine acceleration, for instantly commanding engagement of said overrun clutch.

8. A control system for an automatic power transmission as set forth in claim 7, wherein said engine speed demand sensor comprises a throttle angle sensor for monitoring a throttle valve angular position.