Claims
- 1. A control for operating an engine in a braking mode of operation wherein the engine includes an exhaust valve, comprising:
- an actuator engagable with the exhaust valve;
- means for selecting a braking magnitude from a continuous range of braking magnitudes between minimum and maximum levels;
- means responsive to the selecting means for establishing turn-on and turn-off points for the actuator in dependence upon the selected braking magnitude; and
- means coupled to the establishing means for operating the actuator in accordance with the turn-on and turn-off points to cause the engine to develop the selected braking magnitude.
- 2. The control of claim 1, wherein the establishing means comprises a map addressed by the selecting means.
- 3. The control of claim 2, further including means for detecting engine timing and wherein the operating means includes means responsive to the detecting means and to the map for deriving turn-on and turn-off times for the actuator.
- 4. The control of claim 3, wherein the operating means further includes means responsive to the deriving means for developing drive signals for the actuator from the turn-on and turn-off times.
- 5. The control of claim 1, wherein the selecting means, the establishing means and the operating means are incorporated in a braking control module and further including means for enabling the braking control module when at least one condition is satisfied.
- 6. The control of claim 5, wherein the engine includes a cruise control and wherein the at least one condition comprises engagement of the cruise control.
- 7. The control of claim 5, wherein the engine includes a cruise control and is disposed on a vehicle having a service brake and wherein the enabling means enables the braking control module when the cruise control is engaged and the service brake is engaged.
- 8. The control of claim 7, wherein the enabling means continues to enable the braking control module when the service brake is subsequently disengaged.
- 9. The control of claim 7, wherein the enabling means disables the braking control module when the service brake is subsequently disengaged.
- 10. A control for operating an engine in a braking mode of operation wherein the engine includes a plurality of combustion chambers and wherein a piston operable in a compression stroke is disposed in each combustion chamber and associated with an exhaust valve in fluid communication with such combustion chamber, comprising:
- a plurality of electrically-operable actuators each engagable with an associated exhaust valve;
- a selection switch for selecting a braking magnitude from a continuous range of braking magnitudes between zero and maximum braking levels; and
- a braking control module enabled under certain conditions, the braking control module including
- a map responsive to the selection switch for establishing turn-on and turn-off points for the actuators,
- computational circuits coupled to the map and responsive to an engine speed signal for deriving turn-on and turn-off signals representing turn-on and turn-off times, respectively, for each actuator,
- turn-on and turn-off delay circuits responsive to the turn-on and turn-off signals, respectively, and further responsive to a timing signal representing engine timing,
- a solenoid driver coupled to the turn-on and turn-off delay circuits,
- a cylinder select circuit coupled between the solenoid driver and the actuators and responsive to a cylinder select signal for selecting individual actuators in a sequence and
- a current control coupled between the solenoid driver and the actuators and responsive to the cylinder select signal for operating each actuator as it is individually selected to open the associated exhaust valve during the compression stroke of the piston associated with such exhaust valve in accordance with the turn-on and turn-off points and thereby cause the engine to develop the braking magnitude.
- 11. The control of claim 10, wherein the engine includes a cruise control and the engine is disposed on a vehicle having a throttle pedal, a service brake pedal, a clutch pedal and an engine braking on/off switch and wherein the control further includes means for enabling the braking control module during first and second sets of conditions, the first set of conditions comprising the engine braking on/off switch is on, the engine speed is above a particular level, the throttle and clutch pedals are not depressed and the cruise control is not actuated and the second set of conditions comprising the engine braking on/off switch is on, the engine speed is above the particular level, the throttle and clutch pedals are not depressed, the cruise control is actuated and the service brake pedal is depressed.
- 12. The control of claim 11, wherein the enabling means disables the braking control module when the service brake is disengaged following enabling of the braking control module during the second set of conditions.
- 13. A method of operating an engine in a braking mode of operation wherein the engine includes a plurality of combustion chambers each having an exhaust valve associated therewith, the method comprising the steps of:
- providing a plurality of actuators each engagable with at least one of the exhaust valves;
- selecting a braking magnitude from a continuous range of braking magnitudes between minimum and maximum levels;
- establishing turn-on and turn-off points for the actuators in dependence upon the selected braking magnitude; and
- operating the actuators to open the exhaust valves in accordance with the turn-on and turn-off points and thereby cause the engine to develop the braking magnitude.
- 14. The method of claim 13, wherein the step of establishing comprises the step of addressing a map to obtain turn-on and turn-off signals representing the turn-on and turn-off points, respectively.
- 15. The method of claim 14, further including the step of detecting engine timing and wherein the step of operating includes the step of deriving turn-on and turn-off times for the actuators from the detected engine timing and the turn-on and turn-off signals.
- 16. The method of claim 15, wherein the step of operating further includes the step of developing drive signals for each actuator from the turn-on and turn-off signals.
- 17. The method of claim 16, wherein the step of developing includes the step of passing the turn-on and turn-off signals to a pair of delay circuits responsive to engine timing to obtain first and second control signals.
- 18. The method of claim 17, wherein the step of developing further includes the step of passing the first and second control signals to a solenoid driver and a current control both of which are responsive to a cylinder select signal and coupled to the actuators.
- 19. The method of claim 13, wherein the steps of providing, selecting, establishing and operating are undertaken by a braking control module and including the further step of enabling the braking control module when a plurality of conditions are satisfied.
- 20. The method of claim 19, wherein the engine includes a cruise control and is disposed on a vehicle having a service brake and wherein the braking control module is enabled when the cruise control is engaged and the service brake is engaged.
CROSS-REFERENCE TO RELATED APPLICATION
This application is a divisional of application Ser. No. 08/468,937, filed on Jun. 6, 1995, now U.S. Pat. No. 5,540,201, which is a continuation of application Ser. No. 08/282,573 filed on Jul. 29, 1994, abandoned.
US Referenced Citations (19)
Foreign Referenced Citations (2)
Number |
Date |
Country |
2151331 |
Apr 1973 |
DEX |
9103630 |
Mar 1991 |
WOX |
Divisions (1)
|
Number |
Date |
Country |
Parent |
468937 |
Jun 1995 |
|
Continuations (1)
|
Number |
Date |
Country |
Parent |
282573 |
Jul 1994 |
|