公开(公告)号：EP1473611A4

公开(公告)日：2006-01-25

申请号：EP03701875

申请日：2003-01-27

申请人： BOSCH AUTOMOTIVE SYSTEMS CORP

发明人： MATSUZAKI H ,  WATANABE Y ,  SATO E ,  KAWANO T ,  KURIHARA T

IPC分类号： G05B9/02 ,  G05B11/28 ,  G05B23/02

CPC分类号： G05B23/0235 ,  G05B9/02 ,  G05B11/28

摘要： Presence/absence of failure of a PWM-driven load can easily be judged according to the state of pulse voltage applied to the load. A failure diagnosis apparatus (10) judges failure of an electromagnetic valve (2) pulse-width modulation driven by a drive circuit (4) in response to a control pulse signal (P1). A voltage signal (VA) generated by a pulse width modulation drive is input to a smoothing circuit (11) at a connection point (A) between the electromagnetic valve (2) and the drive circuit (4) so as to obtain a smoothing output voltage (VB). It is determined whether the level value of the smoothing output voltage (VB) is a predetermined value determined by the duty ratio of the control pulse signal (P1) which is a duty ratio set for pulse width modulation drive, thereby judging presence/absence of failure of the electromagnetic valve (2).