Adaptive powertrain braking control with grade, mass, and brake temperature

• US 20030036839A1
• Filed: 08/17/2001
• Published: 02/20/2003
• Est. Priority Date: 08/17/2001
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: General Motors Corporation (Motors Liquidation Co. GUC Trust)
• Inventors: Berger, Todd R., Han, Ed E.
• Granted Patent: US 6,625,535 B2
• Time in Patent Office: Days
• US Class Current: 701/70
• CPC Class Codes: B60T 2250/02 Vehicle mass
• CPC Class Codes: B60T 8/18 responsive to vehicle weight or load, e.g. load distribution using electrical circuitry on regulation means B60T8/17; B60T8/30 takes precedence; responsive to weight and speed condition B60T8/58
• CPC Class Codes: B60T 8/245 Longitudinal vehicle inclination
• CPC Class Codes: B60W 10/04 including control of propulsion units
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 10/10 including control of change-speed gearings
• CPC Class Codes: B60W 10/18 including control of braking systems
• CPC Class Codes: B60W 2530/10 Weight
• CPC Class Codes: B60W 2530/16 Driving resistance
• CPC Class Codes: B60W 2540/12 Brake pedal position
• CPC Class Codes: B60W 2552/15 Road slope, i.e. the inclination of a road segment in the longitudinal direction
• CPC Class Codes: B60W 2555/40 Altitude
• CPC Class Codes: B60W 30/18136 Engine braking
• CPC Class Codes: B60W 30/1819 Propulsion control with control means using analogue circuits, relays or mechanical links
• CPC Class Codes: F16H 2059/663 Road slope
• CPC Class Codes: F16H 2200/003 characterised by the number of forward speeds
• CPC Class Codes: F16H 59/52 dependent on the weight of the machine, e.g. change in weight resulting from passengers boarding a bus
• CPC Class Codes: F16H 59/66 Road conditions, e.g. slope, slippery
• CPC Class Codes: F16H 61/21 Providing engine brake control
• CPC Class Codes: F16H 61/66 specially adapted for continuously variable gearings control of exclusively fluid gearing F16H61/38
• CPC Class Codes: F23M 11/02 : Preventing emission of flames or hot gases, or admission of air, through working or charging apertures
• CPC Class Codes: F23M 2900/11021 : Means for avoiding accidental fires in rooms where the combustion device is located
• CPC Class Codes: F24H 1/205 : with furnace tubes

Abstract

A method and apparatus for adapting powertrain braking to mass, grade, and brake temperature. Vehicle mass is determined using a vehicle speed sensor and an tractive effort model based on engine-torque delivered, torque converter multiplications, and transmission ratio and tire rolling radius effects. Road grade is continuously calculated and altitude change is calculated based on grade and distance traveled. To achieve an ideal amount of powertrain braking, powertrain braking is directed towards a designed coast performance target based on deceleration as a function of vehicle speed. Fuzzy logic is used to evaluate driver intentions, grade load conditions, terrain conditions, brake conditions and other vehicle information to determine the actual, optimal powertrain braking control. A real time brake thermal model is developed to provide increased powertrain under extreme brake conditions. The powertrain braking efforts are limited when restricted by available tractive efforts.

Claims

1. A method of controlling a level of powertrain braking in an internal combustion engine of a vehicle with an automatic transmission and driven wheels, comprising the steps of:

determining a vehicle mass;

determining a road load;

determining a brake load;

determining a powertrain braking control target using the vehicle mass, the road load and the brake load; and

implementing the braking control target.

2. The method according to claim 1, further comprising the step of:

blocking the step of implementing the braking control target when an available tractive effort is insufficient.

3. The method according to claim 1, wherein the step of using the vehicle mass, the road load and the brake load to create a powertrain braking control target further comprises the step of

using fuzzy logic to create the powertrain braking control target.

4. The method according to claim 1, wherein the step of using the vehicle mass, the road load and the brake load to create a powertrain braking control target further comprises the steps of:

determining a driver braking intent;

determining a brake temperature;

determining a road grade; and

using fuzzy logic to create the powertrain braking control target using the vehicle mass, the road load, the driver braking intent, the brake temperature, and the brake load.

5. The method according to claim 1, wherein the step of implementing the braking control target comprises the step of:

supplying a braking torque to the driven wheels.

6. The method according to claim 1, wherein the step of implementing the braking control target comprises the step of:

instructing a driver to command a manual shift of the transmission.

7. The method according to claim 1, wherein the step of implementing the braking control target comprises the step of:

shifting the transmission into a lower engine braking gear.

8. An apparatus for controlling a level of powertrain braking in an internal combustion engine of a vehicle with an automatic transmission and driven wheels, comprising:

means for determining a vehicle mass;

means for determining a road load;

means for determining a brake load;

means for determining a powertrain braking control target using the vehicle mass, the road load and the brake load; and

means for implementing the braking control target.

9. The apparatus according to claim 8, further comprising:

means for blocking the means for implementing the braking control target when an available tractive effort is insufficient.