Active brake booster system
A brake booster system for a motor vehicle of a type having an internal combustion engine without a conventional throttle-type valve in an intake manifold for engine output control. In accordance with the present invention, a throttleless-type IC engine of the above described type is modified to include a valve which can periodically close or obstruct the path of intake air to the IC engine to generate intake manifold vacuum to provide a needed pressure differential for brake booster operation. The system includes a pressure transducer which controls operation of the valve to provide the desired control of engine brake booster vacuum.
1. A brake booster system for a motor vehicle of a type having an internal combustion engine with a throttle-less intake manifold not having a throttle valve for controlling output of the engine, an air induction system, and a vacuum actuated brake booster, comprising:
a vacuum pressure transducer for measuring the pressure in the brake booster and producing a vacuum pressure signal,
a hose means for connecting the brake booster with the intake manifold,
a valve means moveable between a first position for at least partially blocking airflow through the air induction system thereby developing vacuum pressure in the intake manifold, and a second position in which the valve means does not obstruct the airflow path through the air induction system, the valve means further closing a flow path between the intake manifold and the brake booster when the valve means is in the second position thereby maintaining vacuum pressure in the brake booster,
an actuator for controlling the position of the valve means in response to the pressure signals to enable desired vacuum pressure to be maintained in the brake booster, and
a controller for receiving the vacuum pressure signal and providing a control signal for the actuator.
2. A brake booster system in accordance with claim 1 wherein the valve means partially obstructs airflow from the air induction system in the first position.
3. A brake booster system in accordance with claim 1 wherein the controller controls the actuator to move the valve means to the first position when the air pressure in the brake booster is above a first predetermined level, and moving the valve means to the second position when the air pressure in the brake booster is below a second predetermined level.
4. A brake booster system in accordance with claim 1 wherein the controller actuates the valve means to move to the first position for a period of time of less than one second.
5. A brake booster system in accordance with claim 1 wherein the controller actuates the valve means to move to the first position for a period of time of less than 400 ms.
6. A method of operating a brake booster system for a motor vehicle of a type having an internal combustion engine with a throttle-less intake manifold not having a throttle valve for controlling output of the engine, an air induction system, and a vacuum actuated brake booster, comprising:
providing a vacuum pressure transducer for measuring the pressure in the brake booster and producing a vacuum pressure signal,
providing a hose means for connecting the brake booster with the intake manifold,
providing a valve means moving between a first position for at least partially blocking airflow through the air induction system thereby developing vacuum pressure in the intake manifold, and a second position in which the valve means does not obstruct the airflow path through the air induction system, the valve means further closing a flow path between the intake manifold and the brake booster when the valve means is in the second position thereby maintaining vacuum pressure in the brake booster,
providing an actuator for controlling the valve means in response to the pressure signals to enable desired vacuum pressure to be maintained in the brake booster, and
receiving the vacuum pressure signal and providing a control signal for the actuator causing the valve means to move to the first position when the pressure in the brake booster is above a first predetermined level, and causing the valve means to move to the second position when the pressure in the brake booster is below a second predetermined level.
7. A method of operating a brake booster system in accordance with claim 6 wherein the valve means partially obstructing airflow from the air induction system in the first position.
8. A method of operating a brake booster system in accordance with claim 6 further comprising maintaining the valve means in the first position for a period of time less than one second.
9. A method of operating a brake booster system in accordance with claim 7 further comprising maintaining the valve means in the first position for a period of time less than 400 ms.
10. A brake booster system for a motor vehicle of a type having an internal combustion engine with a throttle-less intake manifold not having a throttle valve for controlling output of the engine, an air induction system, and a vacuum actuated brake booster, comprising:
a vacuum pressure transducer for measuring the pressure in the brake booster and producing a vacuum pressure signal,
a hose means connecting the brake booster with the intake manifold,
a valve means moveable between a first position for fully obstructing airflow through the air induction system thereby developing vacuum pressure in the intake manifold, and a second position in which the valve means does not obstruct the airflow path through the air induction system,
an actuator for controlling the position of the valve means in response to the pressure signals to enable desired vacuum pressure to be maintained in the brake booster, and
a controller for receiving the vacuum pressure signal and providing a control signal for the actuator.
11. A brake booster system in accordance with claim 10 further comprising the valve means closing a flow path between the intake manifold and the brake booster when the valve means is in the second position thereby maintaining vacuum pressure in the brake booster.
12. A brake booster system in accordance with claim 10 wherein the controller controls the actuator to move the valve means to the first position when the air pressure in the brake booster is above a first predetermined level, and moving the valve means to the second position when the air pressure in the brake booster is below a second predetermined level.
13. A brake booster system in accordance with claim 10 wherein the controller actuates the valve means to move to the first position for a period of time of less than one second.
14. A brake booster system in accordance with claim 10 wherein the controller actuates the valve means to move to the first position for a period of time of less than 400 ms.
15. A method of operating a brake booster system for a motor vehicle of a type having an internal combustion engine with a throttle-less intake manifold not having a throttle valve for controlling output of the engine, an air induction system, and a vacuum actuated brake booster, comprising:
providing a vacuum pressure transducer for measuring the pressure in the brake booster and producing a vacuum pressure signal,
providing a hose means for connecting the brake booster with the intake manifold,
providing a valve means moving between a first position fully obstructing airflow path from the air induction system in the first position thereby developing vacuum pressure in the intake manifold, and a second position in which the valve means does not obstruct the airflow path through the air induction system,
providing an actuator for controlling the valve means in response to the pressure signals to enable desired vacuum pressure to be maintained in the brake booster, and
receiving the vacuum pressure signal and providing a control signal for the actuator causing the valve means to move to the first position when the pressure in the brake booster is above a first predetermined level, and causing the valve means to move to the second position when the pressure in the brake booster is below a second predetermined level.
16. A method of operating a brake booster system in accordance with claim 15 further comprising the valve means closing a flow path between the intake manifold and the brake booster when the valve means is in the second position thereby maintaining vacuum pressure in the brake booster.
17. A method of operating a brake booster system in accordance with claim 15 further comprising maintaining the valve means in the first position for a period of time less than one second.
18. A method of operating a brake booster system in accordance with claim 15 further comprising maintaining the valve means in the first position for a period of time less than 400 ms.
19. A brake booster system in accordance with claim 1 further comprising the hose means forming at least a part of the flow path.
20. A brake booster system in accordance with claim 6 further comprising the hose means forming at least a part of the flow path.