BWS(Back Warning System) ) BACK WARNING SYSTEM This system an auxiliary device for enhancing the convenience of driving condition using warning(indicator, buzzer system sensing an object within 120㎝ in rear direction and 60㎝ in corner direction and then indicating how close with the object when the car is driven in less than 10km/h or when the driver is parking the car. However, this system does not exempt the driver from the duty of attention. In this system, as limited are the sensing range and sensible objects, the driver should not trust this system thoroughly and fully pay attention to all direction. 1. COMPONENTS A. BWS ECU (1) When the car is driven in rear direction if an object is found then it generates a various warning sound by receiving a signal of ultra-sonic wave sensor installed at the rear bumper. (2) When the ultra-sonic wave sensor is malfunction, a warning sound relevant to the kinds of malfunction of the sensor is generated. ※This is installed at the left quarter panel of the trunk room. B. Ultra-sonic wave sensor (SENSOR ASS’Y) (1) Kind of the sensor ①“L” sensor: Sensor installed at the left side from the center of bumper. ②“C” sensor: Sensor installed at the center of bumper ③“R” sensor: Sensor installed at the right side from the center of bumper. ㅊ (2) Terminology for the ultra-sonic sensor ① TX: Transmitting the original wave. ② RX: Receiving the reflective wave. 2. PERFORMANCE A. General specification of BWS (1) Rated Voltage: DC 12.0V (2) Operating Voltage: DC 9.0 ~ 16.0V (3) Operating Temperature: -30℃ ~ +80℃ (4) Preserving Temperature: -40℃~ +85℃ (5) Sensing Range: 40㎝~ 120㎝ (6) Operating Current - ECU: less than 600.0㎃(DC 12.0V) - Sensor: less than 20㎃(DC 8.0V) (7) Operating Frequency: 40㎑± 5㎑ (8) Effective Operating Velocity: less than10Km/h B. Method for testing BWS ultra-sonic wave sensor After an arbitrary object is disposed at the rear of the car, drive the car varying the position at which the distance from the object is 120㎝ to 25㎝, and measure the distances at which the first, second and third warning sounds are generated. 517 C. Range for sensing single object of BWS ultra-sonic wave sensor (1) Horizontal sensing range: at 70±5㎝ 100°Min. , at 100±5㎝ 40°Min. (2) Vertical sensing range: at 50±5㎝ 60°Min. , at 110±5㎝ 20°Min. D. BWS Sensing range and Warning method The warning is generated when the object is closed to the rear sensor of the car as follows. E. Warning method when BWS ultra-sonic sensor is malfunction After electric power is supplied, if the gear shift is set in the rear (“R”) position, the following warning sounds are generated in according what sensor is malfunction. 3. Specification A. BWS ECU Circuit Diagram B. BWS ultra-sonic wave sensor Circuit Diagram C. Pseudo Arrangement Diagram and Operating Process of BWS ultra-sonic wave sensor (1) Direct sensing method (TX ⇒RX sensor): Sensor L ⇒Sensor L, Sensor C ⇒Sensor C, Sensor R ⇒Sensor R (2) Indirect sensing method (TX ⇒RX sensor): Sensor C ⇒Sensor L, Sensor C ⇒Sensor R Among the above five methods, the object is sensed by the method in which the object is closest and the signal from that method has priority. D. Driving frequency of the three BWS ultra-sonic wave sensors (1) Driving time interval for one Sensor (T4): 65 ± 2msec (2) Sensor Driving Frequency (T5): 325 ± 5msec 4. CONNECTOR PIN ASSIGNMENT A. Connector B. Connector pin function C. Sensor connector D. Buzzer location 5. OTHER ITEMS A. For the following cases, this system may work abnormally. (1) When the sensor is frozen (If the system is unfrozen, then it will work normally) (2) When foreign materials such as snow or water drop are covering the surface of the sensor. (If the foreign materials or any obstacles on the surface of the sensor are removed, the system will work normally) B. For the following cases, the sensing range may be reduced. (1) When foreign materials such as snow or water drop are covering the surface of the sensor (If the foreign materials are removed, then the sensing range will be recovered) (2) When the weather is severely hot or cold. (3) When the object is smaller than 14㎝ in diameter or 1m in length C. For the following cases, the system may work abnormally. (1) When the car is driven in rear direction on the uneven roads, gravel roads, inclined roads, or in the cluster of grasses (2) When closed is the object generating an ultra-sonic waves such as horn sound of vehicles, engine sound of bikes, air brake sound of the large vehicles. (3) When it is heavy rain or water is spread. (4) When a radio receiver is used near by the sensor. (5) When the sensor is covered by snow. D. The system may fail to sense the following objects. (1) A sharp object or thin object such as rope. (2) A material can absorb the sonic waves easily such as cotton cloth, sponge or snow. E. Cautions for sensor test (1) Do not supply a DC voltage at the RX and TX terminal of the sensor. (2) Do not contact sharpen objects to the surface of the sensor or do not impact thereon. F. Others (1) The warning alert may not generated sequentially in according to the vehicle driving speed or the shape of the target objects. (2) If the height of the bumper or the installing condition of the sensor is changed or if an additional accessory which is not enclosed when the car is delivered is installed at the sensing range of the sensor, then this system may work abnormally. (3) Please be noticed that this system may not sense when the object is disposed within 30㎝ from the sensor. (4) Please remove the foreign material on the sensor with smooth clothes if the sensor is indicated as in malfunction, it may be covered by snow or water, or it may be frozen. (5) Please do not press with strength, apply an impact with hard material or scratch with a sharp material on the surface of the sensor. (6) When the vehicle having this system is turn over to another person, please inform the contents of the User’s manual of this system to him or her.