| 摘要 |
A normally open isolation valve 22 is connected between a master cylinder 14 and selected wheel brake(s) (as shown, rear brakes 20a, 20b), and a normally-closed dump valve 26 is connected between the selected wheel brake(s) and a fluid accumulator 28 or master cylinder reservoir 14b. When a slip condition of the controlled wheel(s) is detected, a computer control module 30 closes the isolation valve 22 to hold fluid pressure to the controlled brake(s) at a constant level. If after valve 22 has been closed the deceleration of the controlled wheel(s) exceeds a predetermined amount, the control module will selectively open the dump valve 26 to enable fluid to flow into the accumulator 28 (reservoir) thereby reducing the fluid pressure to the controlled wheel brake(s) and reducing the deceleration of the associated wheel(s). The control module monitors changes in wheel deceleration to detect when the vehicle travels from a relatively-low-friction surface such as wet asphalt to a relatively-high-friction surface such as a dry concrete and vice versa. The control module is responsive to selectively open the isolation valve 22 after the valve has been closed to increase pressure to the controlled wheel brake(s) 20. The module also responds to a pressure differential switch 44. Computer program is described in detail. <IMAGE>
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