Throttle valve

Claim 1

Throttle valve (10) for an internal combustion engine, having a) a shaft (12), on which the valve (10) is mounted, b) a stop point (30), which limits the opening movement of the throttle valve (10) in the direction of the open position, c) a device (18, 20) for displacing the stop point (30) in the direction of the open position in response to the actuation of a mechanical cable pull (20) via the accelerator, d) a spring (32) biasing the throttle valve (10) in the direction of the stop point (30), e) a servomotor (42) which controls the throttle valve (10) between its closed position and its maximum open position defined by the stop point (30), f) a restoring spring (24), which actuates the stop point in the direction of the closed position of the throttle valve (10) when the mechanical cable pull (20) is slack, and g) said throttle valve biasing spring (32) being weaker than said restoring spring (24), h) a reference value transmitter ( 72) for a pivoting part (60) and an actual value transmitter (68), associated with the servomotor (42), for the throttle valve position, i) the mechanical cable pull (20) acting on the pivoting part (60), which cooperates with the stop point (88) in order to displace the same, j) a pivoting restoring spring (70) biasing the pivoting part (60) in the closing direction, k) a stop actuator (92) associated with the pivoting part (60) and, in normal operation, limiting the pivoting of the pivoting part in the closing direction to a minimum angle which is larger than the idling position of the throttle valve (10), characterized in that l) said stop actuator (92) consists of an electromagnet, which in the excited state moves out a pin (94), in order actively to engage a first step (96), m) the stop actuator (92) defines two steps, the first corresponding to normal operation, and the second being actuated if a malfunction of the servomotor (42) is detected, n) said second step permitting further closing of the throttle valve in comparison to the first step, o) a stop limiter (54) limits the pivoting of the stop point (30) in the throttle valve close direction.