| 摘要 |
PURPOSE:To inform a driver before a frozen point is reached by detecting atmospheric temperature and absolute atmospheric humidity, and processing those detection signals by an arithmetic control means and finding whether or not the ambient temperature and humidity of a road surface meet road surface freezing conditions. CONSTITUTION:A freezing condition decision part 6 receives a signal outputted from a road surface calculation part 5 and compares it with an internally set value B of temperature to judge whether or not the road surface temperature tr falls below the temperature where water is frozen. A dew condensation condition decision part 8 detects a signal of the quantity Xstr of saturated vapor corresponding to the signal of the road surface temperature tr outputted from a signal conversion part 7 by an absolute atmospheric humidity detecting means 2 and also compares a signal of the absolute humidity (x) with a rain signal to judge whether or not the dew condensation conditions are satisfied. A freezing logic decision part 9 receives two output signals from said dew condensation condition decision part 8 and freezing condition decision part 6 and ANDs them, thereby outputting the result. Namely, when said two decision conditions are satisfied, a road surface freezing signal is sent to an output means 4 to give a warning to a driver.
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