Granted Patent B2

US 7,051,859 · App. 10/229,187 · Granted May 30, 2006

Abstract

Claims (45)

1. A method for immobilizing an output shaft of an automatic transmission in a hybrid vehicle, the method comprising the steps of:

evaluating a plurality of status flags;

in response to the status of the status flags, grounding a one-way clutch to said automatic transmission, thereby immobilizing a planet carrier connected to said one-way clutch; and

simultaneously immobilizing a sun gear connected to an output shaft.

2. The method of claim 1 , wherein said step of immobilizing a ring gear comprises the step of actuating a transmission control element, said transmission control element being connected to said sun gear.

3. The method of claim 2 , wherein said step of actuating a transmission control element comprises the step of evaluating a plurality of variables prior to actuating said transmission control element.

4. The method of claim 3 , wherein said step evaluating a plurality of variables prior to actuating said transmission control element comprises

evaluating a plurality of enable conditions.

5. The method of claim 4 , wherein said step evaluating a plurality of status flags comprises the steps of:

checking for at least one throttle position sensor fault;

checking for at least one vehicle speed sensor fault;

checking for at least one brake switch fault; and

checking for at least one shift solenoid sensor fault.

6. The method of claim 4 , wherein said step evaluating a plurality of enable conditions comprises the steps of:

evaluating a vehicle speed condition variable;

evaluating for a throttle position variable;

evaluating a brake status variable; and

evaluating a transmission selection variable.

7. A method for immobilizing an output shaft of an automatic transmission in a hybrid vehicle, the method comprising the steps of:

evaluating the status of a plurality of variables, comprising the step of evaluating a plurality of enable conditions:

in response to the status of said plurality of said variables, grounding a sun gear to a transmission housing; and

simultaneously grounding a one-way clutch to said transmission housing, said one-way clutch being connected to a planet carrier, thereby immobilizing said output shaft.

8. The method of claim 7 , wherein said step of evaluating a plurality of variables prior to actuating said transmission control element comprises

evaluating a plurality of status flags.

9. The method of claim 8 , wherein said step evaluating a plurality of status flags comprises the steps of:

checking for at least one throttle position sensor fault;

checking for at least one vehicle speed sensor fault;

checking for at least one brake switch fault; and

checking for at least one shift solenoid sensor fault.

10. The method of claim 7 , wherein said step evaluating a plurality of enable conditions comprises the steps of:

evaluating a vehicle speed condition variable;

evaluating for a throttle position variable;

evaluating a brake status variable; and

evaluating a transmission selection variable.

11. A method comprising the steps of:

grounding a one-way clutch to a transmission housing, thereby immobilizing a planet carrier connected to said one-way clutch; and

in response to a signal, simultaneously immobilizing a ring gear connected to an output shaft;

evaluating a plurality of variables prior to actuating said transmission control element, comprising the steps of:

evaluating a plurality of status flags; and

evaluating a plurality of enable conditions; and

wherein said step of evaluating a plurality of status flags comprises the steps of:

checking for at least one throttle position sensor fault;

checking for at least one vehicle speed sensor fault;

checking for at least one brake switch fault; and

checking for at least one shift solenoid sensor fault.

Assignments (13)