| 摘要 |
<p>A crash sensor (12) for automobiles of the type including a ball (20) moving against viscous damping in a closed tube (24, 124, 224) has a power transistor (150) to switch power in the firing circuit (14, 19, 219). A resistance sensing circuit (220, 228) enables the crash sensor to monitor a change in the resistance of the firing circuit. In one embodiment a simple message pattern eliminates need for more than two wires (158, 232) to the crash sensor. A latching circuit (170) maintains the switch in its closed state after initial closing. The small size of the ball enables use of a plastic or aluminium tube. The tube may have fluted walls that form air channels (66, 166, 266) that viscously conduct much of the air displaced when the ball moves. The small ball and electronic components allow simple contacts (20, 32, 34). The combination of these elements provides a crash sensing and diagnostic system (40) costing much less than known systems.</p> |
