| 摘要 |
PROBLEM TO BE SOLVED: To more properly judge idle running of the electric pump for circulating a cooling medium used for a cooling device of an internal combustion engine without using an electric motor current, and appropriately respond when it is judged that an electric pump has been running idle. SOLUTION: In a cooling device of an internal combustion engine, when duty ratio dB is not less than a threshold value dBref and a revolution speed Np of the electric pump 30 is not less than a threshold value Nref and besides when a revolution speed difference calculated by subtracting an estimated revolution speed Nest from the revolution speed Np of the electric pump 30 is not less than a threshold valueΔNref, the idle running of the electric pump 30 is determined (S130 to S150). When the idle running determined continued and a given idle running time period has elapsed, the electric pump 30 is suspended for a given stop time period (S160, S190 to S210). As a result, without detecting the current passing through a coil of the electric pump 30, the idle running of the electric pump 30 can be more properly judged, preventing overheating and damage in the electric pump 30. COPYRIGHT: (C)2009,JPO&INPIT
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