SENSORS AND THE AUTOMOBILE
In the 1960s, vehicles were equipped with oil pressure, fuel level and temperature coolant sensors. Their outputs were connected to analogue gauges or "idiot" lights. As we entered the 1970s and emissions became a driving factor, more sensors were added to help control the power train. With the addition of the catalytic converter, electronic ignition and fuel injection a number of sensors came required to help maintain tight air/fuel control and exhaust emissions. In 1980s, safety became a factor with antilock brakes and airbags.
Today sensors are everywhere. In the power train area, sensors are used to measure the temperature and pressure of most of the fluids (air temperature, manifold absolute pressure, coolant temperature, and fuel injection pressure). Speed and position sensors are connected to most moving parts (vehicle speed, throttle position, camshaft, crankshaft, transmission shift position, valve position and transmission speed sensors). Others measure knock, engine load, engine misfire and oxygen level in the exhaust. Climate control requires the use of various sensors in the air conditioning system to determine refrigerant pressure and temperature and interior air temperature.
Sensors have been added to the interior to determine seat position. With the addition of antilock braking and suspension control a number of sensors have been added to determine wheel speed, ride height and tire pressure. As airbags were added for frontal and side impact, more crash sensors and accelerometers were added to control airbag deployment. As the concern for front seat passengers has grown so has the need for sensors to determine if the passenger airbag needs to deploy.
Occupant position sensors, passenger weight sensors and others have been developed to ensure the correct deployment of the front passenger airbag. Other sensors are being added as car manufacturers add side impact bags, roof airbags and sophisticated side impact head protection airbags.
As engineers have moved beyond antilock braking and traction control into electronic stability control, more sensors are required. Yaw rate, steering wheel angle and collision avoidance sensors, such as radar sensors or sensors to determine the proximity of other vehicles, will be added. Additional sensors to help control or determine lateral acceleration speed of each wheel and engine torque will be needed.
Control of the vehicle's braking system is tied into the stability control system. The first oil pressure and coolant temperature sensors were set up to work independently of each other. In fact some of them were nothing more than switches that were activated at certain maximum or minimum levels. As more sensors become electronic or digital, they are interconnected and their output is used for more than one vehicle system. Thus sensor manufacturers are searching for better ways to design and manufacture sensors.
1. Which instrument shows you:
· how fast the car is travelling? _________________________________
· warns you if the engine lubrication system gets too hot? ____________
· shows that you are indicating to turn left or right? _________________
· shows you how often the engine is turning over? __________________
· shows you how much petrol you have in the tank? ________________
· indicates the voltage of the car’s electrical system? ________________
2. Match each abbreviation with its meaning:
3. Translate the following extract in written form: