Abstract: An activation device for a passenger protection apparatus is made up of a sensor for detecting a roll angular velocity of a vehicle, a unit for calculating a roll relative angle on the basis of the roll angular velocity, and a unit for making a judgment indicating a roll of the vehicle when the velocity and the angle satisfy a threshold condition. A control unit activates an air bag when making a judgment indicating a roll. A vehicle collision state is discriminated on the basis of right-hand and left-hand accelerations detected by acceleration sensors and the threshold condition for the judgment on a roll of the vehicle is switched in accordance with the collision state. This enables a trip-over type roll to be detected at an early stage for activating the passenger protection apparatus quickly.

Abstract: A satellite sensor and a floor sensor are provided in a forward portion and a central portion, respectively, of a vehicle body. A calculated value and a speed are determined through predetermined processing of a deceleration detected based on an output signal of the floor sensor. If a value determined from the relationship between the calculated value and the speed exceeds a predetermined threshold changing pattern, an airbag apparatus is activated. The threshold changing pattern is set by selecting a map from a Hi map, a Lo1 map, a Lo2 map and a Lo3 map based on a deceleration determined from an output signal of the satellite sensor. If a map different from the current map is to be set as a threshold changing pattern, the threshold changing pattern is set to the desired map after a state that allows the map to be set continues for a time corresponding to a difference between the two maps.

Abstract: A passenger-protecting device such as an air-bag system is activated upon detection of a vehicle lateral inclination angle exceeding a predetermined critical level. Such detection is performed by a lateral inclination detector having a pair of gravitational acceleration sensors for detecting a static road inclination and an angular velocity sensor for detecting a dynamic roll angle of the vehicle. Sensing directions of the pair of gravitational acceleration sensors are positioned to cross each other with a right angle and to make an angle of 45° with respect to a vehicle floor. The dynamic roll angle is calculated by integrating outputs of the angular velocity sensor. The vehicle inclination angle is obtained to summing up the static inclination angle and the roll angle. The passenger-protecting device is timely activated to protect passengers from overturn impact of the vehicle.

Abstract: A satellite sensor and a floor sensor are provided in a forward portion and a central portion, respectively, of a vehicle body. A calculated value and a speed are determined through predetermined processing of a deceleration detected based on an output signal of the floor sensor. If a value determined from the relationship between the calculated value and the speed exceeds a predetermined threshold changing pattern, an airbag apparatus is activated. The threshold changing pattern is set by selecting a map from a Hi map, a Lo1 map, a Lo2 map and a Lo3 map based on a deceleration determined from an output signal of the satellite sensor. If a map different from the current map is to be set as a threshold changing pattern, the threshold changing pattern is set to the desired map after a state that allows the map to be set continues for a time corresponding to a difference between the two maps.

Abstract: A crash mode determining unit comprises first and second acceleration sensors disposed on both sides of a vehicle and a third acceleration sensor disposed almost at a center of the vehicle. A relative line integration length of one of the integrated outputs of the accelerations detected by the first and second acceleration sensors with respect to the integrated output of the acceleration detected by the third acceleration sensor is calculated. The relative line integration length of the integrated output becomes long when a crash mode is either a pole crash or a under-ride crash. Therefore, the crash mode of the pole crash or the under-ride crash can be determined by comparing the relative line integration length with a predetermined length.

Abstract: A crash determination device employed in a vehicle side impact passenger protection system uses logic circuits or microcomputers to correctly determine whether an impact is a crash with an obstruction such as another vehicle by making use of a phase difference between detected accelerations of a side acceleration sensor and a central acceleration sensor. By making use of the phase difference between detected accelerations of side and center acceleration sensors, a high-speed crash can be correctly distinguished from a low-speed impact and an erroneous determination resulting in the passenger protection system being operated in a side impact situation not necessitating operation of the passenger protection system can be avoided.

Abstract: A trigger device for a vehicle safety apparatus includes an acceleration sensor for detecting an acceleration of a vehicle and generating an electric acceleration signal representative thereof, an integration section for integrating the acceleration signal during each given integration period and generating an integration value representative of a result of the integrating, a determination section for determining whether or not a collision of the vehicle is present on the basis of the integration value generated by the integration section, and a trigger section for triggering the vehicle safety apparatus when the determination section determines a collision of the vehicle to be present.