METHOD AND APPARATUS FOR MAXIMUM AND MINIMUM OUTPUT TORQUE PERFORMANCE BY SELECTION OF HYBRID RANGE STATE AND INPUT SPEED FOR A HYBRID POWERTRAIN SYSTEM

• US 20090118948A1
• Filed: 09/24/2008
• Published: 05/07/2009
• Est. Priority Date: 11/04/2007
• Status: Active Grant

• Current Assignee: Bayerische Motoren Werke AG, Daimler AG (Mercedes-Benz Group AG), Chrysler Group LLC (Stellantis NV)
• Original Assignee: BMW AG (Bayerische Motoren Werke AG), Daimler AG (Mercedes-Benz Group AG), GM Global Technology Operations Incorporated (Motors Liquidation Co. GUC Trust), Chrysler LLC (Stellantis NV)
• Inventors: Heap, Anthony H., Kim, Kee Yong, Mcconnell, Jason J.
• Granted Patent: US 8,396,634 B2
• Time in Patent Office: Days
• US Class Current: 701/55
• CPC Class Codes: B60K 6/445 Differential gearing distribution type
• CPC Class Codes: B60L 2240/486 Operating parameters
• CPC Class Codes: B60W 10/02 including control of driveline clutches
• 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 10/08 including control of electric propulsion units, e.g. motors or generators
• CPC Class Codes: B60W 10/115 with planetary gears
• CPC Class Codes: B60W 10/24 including control of energy storage means
• CPC Class Codes: B60W 20/00 Control systems specially adapted for hybrid vehicles hybrid vehicle design, B60K6/00; electric vehicles B60L
• CPC Class Codes: B60W 20/40 Controlling the engagement or disengagement of prime movers, e.g. for transition between prime movers power-up or power-down of the driveline B60W30/192
• CPC Class Codes: B60W 2050/0004 In digital systems, e.g. discrete-time systems involving sampling
• CPC Class Codes: B60W 2510/105 Output torque
• CPC Class Codes: B60W 2540/10 Accelerator pedal position
• CPC Class Codes: B60W 2710/105 Output torque
• CPC Class Codes: B60W 30/18009 related to particular drive situations
• CPC Class Codes: B60W 30/188 Controlling power parameters of the driveline, e.g. determining the required power
• CPC Class Codes: B60W 30/1882 characterised by the working point of the engine, e.g. by using engine output chart
• CPC Class Codes: B60W 50/02 Ensuring safety in case of control system failures, e.g. by diagnosing, circumventing or fixing failures
• CPC Class Codes: B60W 50/04 Monitoring the functioning of the control system
• CPC Class Codes: B60W 50/10 Interpretation of driver requests or demands
• CPC Class Codes: Y02T 10/40 : Engine management systems
• CPC Class Codes: Y02T 10/62 : Hybrid vehicles
• CPC Class Codes: Y02T 10/84 : Data processing systems or methods, management, administration

Abstract

A powertrain system includes an engine mechanically coupled to an electro-mechanical transmission selectively operative in one of a plurality of transmission operating range states and one of a plurality of engine states. A method for controlling the powertrain system includes determining a current transmission operating range state and engine state, determining at least one potential transmission operating range state and engine state, providing an operator torque request, determining preferability factors associated with the current transmission operating range state and engine state, and potential transmission operating range states and engine states, preferentially weighting the preferability factors for the current transmission operating range state and engine state, and selectively commanding changing the current transmission operating range state and engine state based upon the preferability factors and the operator torque request.

Claims

1. Method for controlling a powertrain system including an engine mechanically coupled to an electro-mechanical transmission selectively operative in one of a plurality of transmission operating range states and one of a plurality of engine states, comprising:

determining a current transmission operating range state and engine state;

determining at least one potential transmission operating range state and engine state;

providing an operator torque request;

determining preferability factors associated with the current transmission operating range state and engine state, and potential transmission operating range states and engine states;

preferentially weighting the preferability factors for the current transmission operating range state and engine state; and

selectively commanding changing the current transmission operating range state and engine state based upon said preferability factors and said operator torque request.

2. A method according to claim 1 wherein determining preferability factors associated with potential transmission operating range states comprises mathematically reducing the preferability of potential transmission operating range states for which the operator torque request exceeds a deliverable output torque, for each of such potential transmission operating range states, in proportion to the amount of torque by which said operator torque request exceeds said deliverable output torque.

3. A method according to claim 1 wherein determining preferability factors associated with potential transmission operating range states comprises providing a biasing cost function for each potential transmission operating range state, which functions each define a biasing cost profile that includes:

a range of values of torques representing operator torque requests over which the value of the cost function is substantially constant, and at least one range of torques representing operator torque request values for which the cost function varies for operator torque requests having a magnitude between the operator torque request value having the highest magnitude of torque for which the cost function is substantially constant, and the maximum transmission output torque for the potential transmission operating range state under consideration.

4. A method according to claim 3 wherein the value of said biasing cost function is effectively zero over the range of torque values representing operator torque requests at which said cost function is substantially constant.

5. A method according to claim 3 wherein the value of the biasing cost function at torque values associated with operator torque requests for a potential transmission operating range state varies proportionally to the amount by which said torque values associated with operator torque requests exceed the highest magnitude of torque at which said cost function is constant.

6. A method according to claim 1 wherein said preferability factors associated with potential transmission operating range states and potential engine states include new desired operating range preferability factors.

7. A method according to claim 6 wherein selectively commanding changing the transmission operating range state and the present engine state occurs as the result of selection of a numerical value present in said new desired operating range preferability factors selected from the group consisting of:

the lowest numerical value present in said new desired operating range preferability factors and the highest numerical value present in said new desired operating range preferability factors.

8. A method according to claim 1, further comprising periodically repeating the method of claim 1 to provide successive iterations.

9. A method according to claim 8, wherein determining preferability factors associated with the current transmission operating range state and the current engine state utilizes new desired operating range preferability factors from a previous iteration.

10. A method according to claim 7 wherein one of the preferability factors present in the new desired operating range preferability factors is used in providing information to a shift execution module.

11. A method according to claim 10 wherein said shift execution module provides numerical values for the current operating range states of said transmission and the engine in successive iterations of the method of claim 1.

12. A method according to claim 8 wherein said preferability factors associated with potential transmission operating range states and potential engine states includes new desired operating range preferability factors.

13. Method for biasing selection criteria used in selecting an engine operating point from a plurality of engine operating points in each of a plurality of potential transmission operating range states in a motorized vehicle including an engine mechanically coupled to an electro-mechanical transmission, comprising:

providing a minimum torque output value and maximum torque output value for said transmission for a plurality of engine operating points in each potential transmission operating range state, which minimum and maximum values define a potential torque output range for each engine operating point in each potential transmission operating range state;

providing a biasing cost function for a plurality of engine operating points in each potential transmission operating range state over the potential torque output range associated therewith;

providing an operator torque request having a torque magnitude; and

assigning a biasing cost to engine operating points in each potential transmission operating range state based on the magnitude of said operator torque request.

14. A method according to claim 13 wherein a biasing cost is assigned to potential engine operating points within each of a plurality of potential transmission operating range states for which the magnitude of torque represented by said operator torque request is outside of the potential torque output range of said potential engine operating points, based on said biasing cost function.

15. A method according to claim 13 wherein a biasing cost is assigned to potential engine operating points within each of a plurality of potential transmission operating range states of said transmission for which the magnitude of torque represented by said operator torque request is within the potential torque output range of said potential engine operating points, based on said biasing cost function.

16. A method according to claim 13 further comprising selecting an engine operating point from each potential operating range state based on a comparison of the biasing costs assigned to engine operating points for which the magnitude of torque represented by said operator torque request is outside of their potential torque output ranges.

17. A method according to claim 13 further comprising commanding changes of said transmission operating range state based on a comparison of biasing costs assigned to potential transmission operating range states for which the magnitude of torque represented by said operator torque request is outside of their potential torque output ranges.

18. A method according to claim 13 wherein a transmission input speed is selected that results in a lowest total cost, which total cost comprises power losses including those derived from a biasing cost function that biases to select a transmission input speed which provides an output torque that is the closest to said operator torque request when said operator torque request is outside of the potential output torque ranges of the particular potential transmission operating range states under consideration.

19. A method for selecting a transmission operating range state from potential transmission operating range states in a motorized vehicle including an engine mechanically coupled to an electro-mechanical transmission, which comprises:

providing an operator torque request having a magnitude;

providing an on-board microprocessor configured to execute a search engine for selecting a first engine operating point from a search range space containing possible engine operating points associated with a potential transmission operating range state;

calculating maximum and minimum output torques that the drivetrain system is capable of delivering (T_O Max, T_O Min) associated with said first engine operating point;

assigning a biasing cost to the difference between the magnitude of the operator torque request and the torque deliverable by said transmission if operating said vehicle transmission at the parameters defined by said first engine operating point;

summing of power losses associated with operating said vehicle transmission at the parameters defined by said first engine operating point to provide a total power loss;

repetition of said selecting, calculating, assigning, and summing for a plurality of engine operating points in said search range space, so as to provide a total power loss for engine operating points in said plurality;

selecting at least one point from search range space which have the lowest power loss;

repeating said selecting, calculating, assigning, summating, repetition, and selecting for at least two potential transmission operating range states; and

selectively commanding changing the transmission operating range state based upon a comparison of power losses associated with engine operating points.

20. A method according to claim 19 wherein an engine operating point used in selectively commanding is one which has a transmission input speed associated with it which was used as a basis for selecting the particular transmission operating range state selected.

21. A system for controlling a powertrain system including an engine mechanically coupled to an electro-mechanical transmission selectively operative in one of a plurality of transmission operating range states and one of a plurality of engine states, comprising:

a microprocessor configured to receive data and provide an output, said data including

a first set of preferability factors,

a second set of preferability factors relating to desired operating range states of said transmission,

a third set of preferability factors relating to current operating range states of said transmission, and

a fourth set of preferability factors, said fourth set of preferability factors comprising input speed trip preferability factors;

a control module configured to control shifting events in said transmission, said control module having inputs and outputs, wherein output from said microprocessor is provided as input to said control module, said control module being configured to provide said third set of preferability factors to said microprocessor as an input thereto; and

an electro-mechanical transmission in effective electrical communication with output from said control module;

said system configured sufficiently that commanded changes of transmission operating range state are executed using biasing costs assigned to potential operating range states of said transmission based on at least one operator torque request, said costs being determined by a biasing cost function which provides a torque reserve.