Just as the human body uses it’s various senses to determine things such as sight, sound, taste, feel and smell, an average “mechatronic” modern vehicle also require signal from every single one of its components to monitor/ make decisions on the vehicle. Decisions such as the “fuel trim”, braking distance, airbag deployment and several others.
These sensors in are embedded in every system and subsystem on the vehicle.
These sensors are built into these systems to ensure the computers (ECUs) are fully aware of the state of things and can use such data to take decisions on how best to improve efficiency at all times the vehicle is operational. They also enable the driver to identify and prevent possible issues before they result in breakdowns that can result in expensive repairs by reporting errors to the computer, which then lights up the malfunction indicator lamp(s).
The faults in a vehicle used to be tricky to diagnose in the past, but with the wirings and connections in modern vehicles, diagnosing a fault when a vehicle malfunctions can becomes a lot more precise if the sensors are communicated with by using an external computer for diagnostics.
Modern vehicles now come with digital computers that aid the control of engine functions, climate control system, headlight and even taillight operation. Many systems are now required to store information for later access. Service technicians can plug their own computers to a vehicle and often swiftly diagnose faults even if the problem is sporadic.
The computer is the brain of a computerized engine control system and sensors are its link to what’s happening under the hood. Many owners are not even aware of the amount of sensors built into their automobiles engine and what value they add. Here are some of the sensors every car owner should be aware of and their functions.
The Oxygen sensor is an electronic device used to measure the proportional amount of oxygen in a liquid or gas. It measures the amount of oxygen that is present in the exhaust pipe and will indicate if the fuel is burning rich or lean and also monitor the amount of oxygen in the exhaust so the ECU can determine how rich or lean the fuel mixture is and make adjustments accordingly. A faulty oxygen sensor can cause a vehicle to idle poorly and jerk as well as cause high fuel consumption.
MASS AIR FLOW (MAF) SENSOR
The Mass Air Flow Sensor (MAF) is a computer-controlled sensor that calculates the volume and density of the air taken in by the engine. It regulates the right amount of fuel used for optimized operating conditions. Basically, the MAF tells the ECU the mass of air entering the engine.
The MAF sensor is usually located near the air filter and monitors the amount of air that enters the engine. A failing MAF sensor will result in rich or lean running conditions, rough idle, hesitation, or stalling, as well as an illuminated “check engine” light, i.e., If this sensor is faulty, the car may stall and the fuel usage will be higher than necessary.
ENGINE SPEED SENSOR/CRANKSHAFT POSITION SENSOR
An engine speed sensor is a device used for reading the rotational speed of the engine. It is usually attached to the cylinder block of the engine, close enough to the crankshaft and monitors its spinning speed. This signal is used to determine ignition timing position of the engine to determine when spark is required in the combustion chamber of the engine; it does this by recording how fast the crankshaft of your vehicle is spinning.
MANIFOLD ABSOLUTE PRESSURE SENSOR
The manifold absolute pressure sensor, also known as the MAP sensor is one of the sensors used in an internal combustion engine’s electronic control system. The sensor generates a signal that is proportional to the amount of vacuum in the intake manifold, the engine computer then uses this information to adjust ignition timing and fuel enrichment. A faulty manifold absolute pressure sensor can lead to excessive fuel consumption, lack of power, and increased emissions.
The spark knock sensor is designed to detect any spark knock, vibrations and abnormal sound and report same to the engine computer for optimum engine performance and protect the engine from power-robbing. When there is a fault, it sends signals to the engine-control computer, thus, prevents erratic explosion.
Often times, the location of the knock sensor depends entirely on how effective it will be in catching the noise an engine makes, however, you can find it bolted on the center of the wall of the cylinder block. There are also some vehicles where the knock sensor is installed on the cylinder head itself.
These are some of the sensors attached to the engine and work with the engine computer. Subsequsntly, we shall be discussing more about sensors, including those on the other systems and subsystems.