Patent Grant
9145886
The disclosure generally relates to vehicle braking systems. More particularly, the disclosure relates to an electric vacuum pump backup control system and method which controls a brake system vacuum booster in the event that a primary electric vacuum pump (EVP) is disabled.
The braking system of modern vehicles may include an electronic control unit (ECU) which controls an electric vacuum pump (EVP) that provides vacuum pressure to a brake system vacuum booster for braking. In the event that the ECU is compromised, the EVP may become disabled. Consequently, the brake system vacuum booster may become incapable of providing boost for braking, in which case braking of the vehicle may require additional effort on the part of the driver.
Accordingly, an electric vacuum pump backup control system and method which controls a brake system vacuum booster in the event that a primary electric vacuum pump (EVP) is disabled is needed.
The disclosure is generally directed to an electric vacuum pump backup control system. An illustrative embodiment of the system includes a brake on/off switch, a primary electric vacuum pump control interfacing with the brake on/off switch, a secondary electric vacuum pump control interfacing with the brake on/off switch and the primary electric vacuum pump control and an electric vacuum pump interfacing with the primary electric vacuum pump control.
In some embodiments, the electric vacuum pump backup control system may include a brake on/off switch; a primary electric vacuum pump control interfacing with the brake on/off switch; a secondary electric vacuum pump control interfacing with the brake on/off switch and the primary electric vacuum pump control and an electric vacuum pump interfacing with the primary electric vacuum pump control. The secondary electric vacuum pump control is adapted to operate the electric vacuum pump responsive to loss of communication with the primary electric vacuum pump control and responsive to receiving a request for activation from the primary electric vacuum pump control. The primary electric vacuum pump control is adapted to resume operation of the electric vacuum pump responsive to restoration of communication between the primary electric vacuum pump control and the secondary electric vacuum pump control and responsive to receiving a request for deactivation from the secondary electric vacuum pump control.
The disclosure is further generally directed to an electric vacuum pump backup control method. An illustrative embodiment of the method includes operating an electric vacuum pump using a primary electric vacuum pump control and operating the electric vacuum pump using a secondary electric vacuum pump control upon deactivation of the primary electric vacuum pump control.
The disclosure will now be made, by way of example, with reference to the accompanying drawings, in which:
The following detailed description is merely exemplary in nature and is not intended to limit the described embodiments or the application and uses of the described embodiments. As used herein, the word “exemplary” or “illustrative” means “serving as an example, instance, or illustration.” Any implementation described herein as “exemplary” or “illustrative” is not necessarily to be construed as preferred or advantageous over other implementations. All of the implementations described below are exemplary implementations provided to enable persons skilled in the art to practice the disclosure and are not intended to limit the scope of the appended claims. Furthermore, there is no intention to be bound by any expressed or implied theory presented in the preceding technical field, background, brief summary or the following detailed description.
Referring initially to
Under normal braking conditions during operation of the vehicle, the vehicle brake pedal 102 is depressed by an operator of the vehicle. The depressed vehicle brake pedal 102 closes the BOO switch 104. The BOO switch 104 actuates the primary EVP control 106, which enters a vacuum pump control state. In the vacuum pump control state, the primary EVP control 106 operates the EVP 108. The EVP 108 generates vacuum (boost) pressure and provides the vacuum pressure to the vehicle brakes 110 through the vehicle brake lines 109. The vehicle brakes 110 slow or stop the vehicle typically depending on the duration and magnitude of foot pressure which the vehicle operator applies to the vehicle brake pedal 102.
Under braking conditions in which the primary EVP control 106 is disabled, the BOO switch 104 actuates the secondary EVP control 112. The secondary EVP control 112 enters a vacuum pump control state and operates the EVP 108. The EVP 108 generates vacuum (boost) pressure and provides the vacuum pressure to the vehicle brakes 110 through the vehicle brake lines 109.
Referring next to
Referring next to
Referring next to
If the primary EVP control 106 has requested activation of the secondary EVP control 112 in block 406, the secondary EVP control 112 may enter the vacuum pump control state and control the EVP 108 in block 410. In block 412, the method may continue to the block diagram 500 in
Referring next to
If the vehicle brake pedal 102 has been applied in block 504, the secondary EVP control 112, responsive to input from the BOO switch 104, may operate the EVP 108 in a cyclical manner in block 506. Accordingly, in some embodiments, the secondary EVP control 112 may operate the EVP 108 for about 100 ms, followed by deactivation of the EVP 108 for about 100 ms and operation of the EVP 108 again for about 100 ms in an alternating manner. The secondary EVP control 112 may continue the foregoing cyclical operational mode of the EVP 108 until the BOO switch 104 indicates that the vehicle brake pedal 102 has been released.
In block 508, the BOO switch 104 may determine whether the vehicle brake pedal 102 has been released. If the vehicle brake pedal 102 has not been released, the method may continue at block 506, at which the BOO switch 104 actuates cyclical operation of the EVP 108. If the vehicle brake pedal 102 has been released at block 508, the BOO switch 104 may actuate final operation of the EVP 108 in block 510. In some embodiments, the BOO switch 104 may actuate final operation of the EVP 108 for about 100 ms. In block 512, the BOO switch 104 may deactivate the EVP 108.
Referring next to
If requests for activation are being received from the primary EVP control 106 in block 604, the secondary EVP control 112 may determine whether communication with the primary EVP control 106 has been restored in block 606. If communication between the secondary EVP control 112 and the primary EVP control 106 has not been restored, the secondary EVP control 112 may continue control of the EVP 108 in block 612 and the method may return to block 602. If communication between the secondary EVP control 112 and the primary EVP control 106 has been restored, the secondary EVP control 112 may exit the vacuum pump control state in block 608 and the primary EVP control 106 may enter the vacuum pump control state in block 610.
Although the embodiments of this disclosure have been described with respect to certain exemplary embodiments, it is to be understood that the specific embodiments are for purposes of illustration and not limitation, as other variations will occur to those of skill in the art.
| Number | Name | Date | Kind |
|---|---|---|---|
| 5881557 | Shields | Mar 1999 | A |
| 5961189 | Lutteke et al. | Oct 1999 | A |
| 6410993 | Giers | Jun 2002 | B1 |
| 6598943 | Harris | Jul 2003 | B2 |
| 20080150351 | Ruffer et al. | Jun 2008 | A1 |
| 20080164753 | Crombez et al. | Jul 2008 | A1 |
| 20090045672 | Nishino et al. | Feb 2009 | A1 |
| 20090236903 | Nishino et al. | Sep 2009 | A1 |
| 20120253574 | Krueger et al. | Oct 2012 | A1 |
| Number | Date | Country | |
|---|---|---|---|
| 20120237360 A1 | Sep 2012 | US |
