Posted at 11.01.2018
Ever since we have established RHR Engineering workshop, we have completed several ECU (Electronic Control Product) mapping. Keeping this in mind, I have made a decision to make a report on ECU, and its operation for our technicians. This statement will instruct our technicians on ECU operation, function, features, and its own principles.
The ECU (Electronic Control Product) or otherwise known as Engine unit Management System is some type of computer which control buttons every action and result of the Engine motor. The ECU involves an 8-32bit microprocessor, Random Access Storage area (RAM), Read Only Ram (ROM), and an Type/Output interface, Analogue & Digital converters and in some cases Electronic Erasable Programmable Read Only Recollection (EEPROM). Random Access Recollection (RAM) is a display ram, which is erased once the car is switched off. It provides the ECU with the info which is necessary at this time of procedure. Whereas, Read Only Recollection (ROM) is long lasting memory, therefore it is non-erasable. It stores all the functions, and module of the operating systems e. g. Ignition Timing, Injection Timing. EEPROM is a superior type of memory, that could be within Aftermarket, and High Valued vehicles. The Function remains exactly like ROM, but the function component could be edited or erased by the drivers regarding to his/her desire, via mailing orders through on dash buttons or by joining your personal computer to the ECU (only in case of Aftermarket ECU). EEPROM provides the driver with choice of driving a vehicle style, performance end result, and controlling characteristics. Analogue & digital converters are used to converts digital signals into analogue impulses and vice versa. For example, speed detectors convert digital sign into analogue sign i. e. Rate gauge.
The ECU manages virtually all the running items of the automobile. The main operating system, which ECU has to control to be able to run the engine unit, is the Energy Treatment System, Ignition Timing, and the Idle Swiftness Control system. Predicated on information from the insight sensors (engine motor coolant temperature sensor, Manifold Total Pressure sensor, Air Flow sensor etc. ), the ECU determines optimum adjustments for the outcome actuators (Injectors, Idle Speed Control Valve etc. ).
Modern day Vehicles are equipped with sophisticated ECUs. They have other features such as, Traction Control, Luxury cruise Control, Active Suspension, Electronic Ignition System, Changing Valve Timing activator, and Abdominal muscles (Anti-Lock Brake System). They also work as diagnostic software, as it stores several Sensors and Actuators around the automobile.
The ECU works on information directed by the receptors. If any correction is to be made, or if any function must be completed, it does it using actuators. Source transmission are received by the detectors and output indicators receive to the actuators. Everything is prepared in digital format.
The main function of the ECU is to handle inspections to ensure right going of the engine. The most frequent checks are the following:
These checks are essential so the vehicle will meet the emission expectations, maintain fuel current economic climate, and become reliable.
The input impulses received by the ECU are dispatched by the Receptors. The sensors act as a stimulus of the ECU. The 3 mostly found Sensors are described as follows:
There are 2 types of air mass meter, hot line type, and vane type. They both serve the same function, however the material used is different. An air mass meter is situated after the air conditioning filter and before the intake plenum. Mid-air mass meter provides the ECU with an analogue transmission that indicates the amount of air being drawn into the engine motor. The ECU then takes this value to include the correct amount of petrol to keep up the 14. 7:1, air: gas ratio.
The most frequent kind of air mass meter is the HOT Line type air mass meter. It really is mainly used in multi-point injector system. It uses an electrified wire, which functions as a resistor. During operation the cable is heated, but when the air passes over the heated up cable, it cools, thus changing the resistance. The ECU monitors the level of resistance value and can work out how much air is getting into the engine motor.
The main function of the oxygen sensor is to measure the amount of oxygen content exiting the exhaust. It also serves the reason to ensure that the air/gasoline concoction is chemically accurate. An oxygen sensor is built in between your exhaust manifold and the catalyst converter.
Oxygen sensor must warm up to approx 350 degrees Celsius to work properly. They send a signal to the ECU via voltage to permit the ECU to maintain, or to perfect the air/ gasoline percentage. The ceramic tip on the finish of the air sensor that protrudes into the exhaust manifold becomes porous and allows the oxygen ions to flow through the tip. This creates the transmission voltage, which changes with change in oxygen level inside the exhaust. This transmission is therefore transmitted to the gasoline injection or even to the ECU, which alters the petrol number as necessary, before oxygen content of the exhaust gas is right for reliable catalytic converter operation, also to maintain fuel current economic climate.
It detects the position of the throttle plate. The ECU maintains the engine unit idle velocity at confirmed value e. g. 800 revs per minute. The ECU recognizes when the engine is at idle from the information given by the throttle position sensor.
The throttle position sensor includes a potentiometer. The wiper of the potentiometer is linked to the throttle plate, so that as the throttle is moved from the finished, to wide-open, the voltage indication from the sensor changes. The voltage sign is handed to the ECU, and used to determine the exact position of the throttle, and the rate of which the throttle has been opened and shut. It helps the ECU to access drivers intensions, like the intention to quickly accelerate, by discovering the acceleration or the rate at which the throttle has been opened.
The output indication from the ECU is received by the Actuators. An actuator is a mechanised device which changes electrical signal into kinetic / mechanised energy. E. g. Injectors, Fuel Pump, idle quickness control valve.
There are 3 types of actuators, Solenoid type e. g. Injector, EGR (Exhaust Gas Recirculation Valve) Valve, Stepper Motor unit type e. g. Idle Velocity Control Valve, and a DC (Immediate Current) Engine type e. g. Fuel Pump.
The Solenoid type actuator runs on the coil of line around a tender metal, through which when the existing goes by it produces a magnetic field. This magnetic field is used to convert electrical energy into mechanical energy (linear motion) e. g. Injector
The function of the injector is to provide a finely atomized squirt of fuel to the inlet manifold or the cylinder head. It is on the inlet manifold following the throttle body.
injector solenoid off
The injector solenoid is connected right to the battery with a relay; the planet earth circuit for the injector is connected to the ECU. When the ECU completes the earth circuit the injector circuit is completed. Once the injector circuit is completed, the current is passed to the solenoid (electromagnetic Coil); this in turn produces magnetic energy, and appeals to the plunger (needle valve), thus beginning the diffuser nozzle, and providing gasoline to the inlet manifold or the combustion chamber.
injector solenoid on
A DC (Direct Current) Electric motor coverts electrical energy into mechanised energy (rotary motion). The most frequent example of DC motor unit type actuator is Gas Pump.
The DC engine functions by electromagnetism. The magnetic make serves perpendicular to both cable and magnetic field. When electric energy passes through a coil in a magnetic field, the magnetic power produces torque which changes the DC electric motor.
The energy pump provides the injector with enough fuel at a sufficient pressure to permit the injectors to give good atomization. In present day vehicles it is situated inside the fuel tank, in order to keep the pump cool, and reduce the noise of procedure.
Unlike the Stepper Motor, the petrol pump runs on the DC (Immediate Current) Motor, therefore it has a continuing operation, and earth connection. Present day vehicle are built in with RUTHLESS Roller- Cell type gas pumps. The Roller cell Pump can be an example of DC motor, as it converts electricity into mechanical energy (rotary action). If the fuel gets into the pump it is compressed by spinning cells which pressure it through the pump at a high pressure.
The pump can create a pressure of 8 club (120 psi. In the pump is a pressure restricting valve, which maintain the pressure through the gas pump. The other end of the pump (output) houses a non-return valve which, when the voltage to the pump is removed, it closes the return to the container, and keeps pressure within the system. The normal operating pressure within this system is around 2 pub (30 psi), of which the current get on the pump is 3 to 5 5 amps.
Stepper Motor is an analogue actuator. They are used to convert electricity into mechanised energy (rotational movements). Unlike a conventional motor unit, a stepper electric motor will rotate however in stages and not full rotations, so that it can open up and close airways partly.
The most usual kind of stepper engine actuator can be an Idle Acceleration Control Valve.
The Idle Speed Control Valve is employed to either regulate the bypass of air throughout the throttle butterfly or as a throttle electric motor controlling the position of the throttle butterfly. The ECU constantly alters the control signal to the motor unit or valve to maintain a continuous idle rate.
In an idle quickness control valve, a stepper electric motor is built into the ISCV where it rotates a valve shaft either in or out. Therefore increases or reduces the clearance between your valve and the valve seat, therefore regulating the amount of air allowed to go through thus controlling the idle. The idle rises when mid-air Condition is started up, this is because of the load on engine received by Air Condition.
Performance of the detectors will depend on their location. A hot cable air mass meter will not perform well if it was located above the exhaust manifold, as it'll heat the cable, and give false reading of air used. This problem will result in incorrect air/fuel mixture, high engine heat, and producing a lot more emissions.
An oxygen sensor will perform best at approximately 350C. the operating temp of the sensor is afflicted by the location in the exhaust: too close to the exhaust manifold can lead to overheating, this will bring about burning the heating system component or the filaments inside thus emitting harmful gases (CO, HC) in the atmosphere, too much from the exhaust manifold and the sensor might not exactly reach its correct operating temp, this will cause emitting dangerous gases (CO, HC) in the atmosphere.
The location of the ECU also issues. Keeping the ECU in the engine unit bay can overheat the processor chip inside the ECU creating delays in insight and output impulses. The very best location for the ECU is under the Passenger compartment, this will keep the temperature low, and it is beneficial for the micro cpu to perform its process well.
Earlier exemplory case of ECU were not as complex as modern ECU. Old ECUs were applied to Single Point Injector system. They were simpler than the present day day ECU, as it used fewer components, and experienced less function to handle.
Single Point injections ECU were required to only perform fuel injections; it still used the traditional ignition system, and had very few detectors, and actuators. Against the present day day ECU it offers few benefits and drawbacks.
Fewer components therefore slicing cost
Less control over the engine
Less components going wrong
Fuel is well atomized
Inappropriate gas distribution
Having less components means it acquired less control over right performing of the engine unit, and achieving the emission requirements. This major drawback lead to the introduction of a much advanced ECU which could be found in modern day vehicle e. g. Multi-Point Shot System.
Multi-Point treatment system homes more sensors and actuators than the One Point injection system. The components found in addition to Solo Point injections are stated below.
Pre and Post Lambda sensor.
Variable Valve Timing actuator.
Hall Impact Sensor
One major addition to the complete operation of the multi-point shot system is the ignition system. Multi Point injections system uses individual coil per each cylinder, whereas Sole Point injections system uses the traditional ignition system. The basic principle of operation for each and every coil remains the same as the conventional.
By having solo coil per cylinder, enough time available to build up coil energy is greater than having a single coil providing spark to all cylinders. For instance with an eight cylinder engine motor with eight specific ignition coils, each coil will have 8 x longer time for you to complete one entire ignition cycle compared to the conventional engine unit using one coil for any cylinders. The available №dwell time is therefore also up to eight times much longer. And there will no lost spark. Therefore, the automobile will need no tuning for acceleration advance, or load move forward, and spark will me more efficient.
Multi-Point injections system has more components, therefore having more control over the engine motor, and getting together with the emission standard. It can help the engine to run more cleaner, and perform better, regarding any weather conditions. It also boosts the fuel current economic climate, as distribution of fuel is appropriate to each cylinder.