Motor Electrical Systems

Motor Electrical Systems

Engine electrical systems consist of electronic control units, electrical cables and battery that provide power to all parts of the car. In today’s modern cars, electrical systems have come to the forefront and control almost any mechanical part. The best known of these is the engine control unit.  Before explaining the  engine control unit (ECU )  , it is necessary to understand what the electronic control unit (ECU) is.

What is the Electronic Control Unit (ECU)?

The electronic control unit (ECU) used in the automotive sector controls all engine electrical systems. There are several modules in the electronic control unit. Some of these are;
– Engine Control Module (ECM)
– Power Control Module (PCM – Powertrain Control Module)
– Transmission Control Module (TCM – Transmission Control Module)
– Brake Control Module (BCM – Brake Control Module)
– Central Control Module (CCM) – Central Control Module
– Central Control Module
(GEM – General Electronic Module)
– Body Control Module
– Suspension Control Module (SCM)
. All of these systems are called the car brain. It can consist of several modules. There are modern cars with 80 ECU modules.

The information is exchanged between these controllers via the CAN BUS line. CAN: The Controller Area Network The CAN-BUS system enables the ECUs to communicate with each other, transmitting signals from sensors to ECUs and from ECUs to activators.

What is the Engine Control Unit and What Does it Do? (ECU – Engine Control Unit), (ECM – Engine Control Module) What is ECU?

The most important part of the electronic control unit in engine electrical systems is the engine control module. In other words, it is the engine control unit (ECU). The engine control unit, also referred to as the engine computer, manages a number of systems that enable the engine to operate, ensuring the engine’s performance. There is a microprocessor card in the engine control unit which is used to start and manage diesel and gasoline engines. This ECU has software in the card memory to ensure that all systems operate in a certain order. It manages the fuel and air systems by comparing them with the software information in its memory within the information it receives from many sensors in the car.

Before the use of the engine control units, the air-fuel mixture, the ignition time and the regulator were mechanically controlled. It now has microprocessors that can be reprogrammed within the engine control unit (ECU) used in all modern cars. It controls various systems by interpreting the information received from the sensors with the help of software in its memory. In short, the ECU serves to control the appropriate injection time and quantity at each engine speed and operating condition, taking into account the emission values.

Engine Control Unit (ECU) What is it?

The information from the sensors is provided in the software in the engine control unit, which is described as the engine computer. What is to be done in line with these incoming values ​​is also certain. According to the registered software, it provides the necessary air-fuel mixture by controlling the actuators that enable the engine to start. The following sections will explain what he does.

– Air controls the fuel mixture

In modern cars, fuel injection systems are used to deliver fuel to the cylinders. The engine control units adjust the amount and time of fuel to be injected with the information received from the sensors.
Oxygen sensors  regularly inform the engine computer, ie the engine control unit, about the quality of combustion. Within the information provided, the engine control unit classifies combustion quality as rich, poor or normal. As a result of this classification, the engine computer controls the fuel and determines the air-fuel mixture ratio.
The throttle position sensor tells the ECU how open the throttle is when you press the accelerator pedal. According to this position information, the brain will adjust the fuel.
Air flow meter (MAF Sensor) informs the ECU how much air has entered the engine. Within this information, the engine computer regulates the fuel.
The engine coolant sensor  measures the temperature and if the engine is still cold, the ECU will spray additional fuel into the engine.

– Controls the Rolanti cycle

It has an engine control unit with many engine idling speed controls. The engine speed is read by the crankshaft position sensor, known as the crankshaft sensor. The crank speed sensor plays a major role in fuel injection timing, ignition timing and valve opening timing. The idle speed is regulated by the programmable throttle or the idle motor. The engine control unit, which receives the speed information from the crank speed sensor, sends a signal to the throttle valve or the relay motor to bring the engine to the idle speed stored in the software. In order to avoid confusion, there is no rolant motor in the electrically controlled throttle. What is the throttle and rolant motor? on the page.

*  Cruise control and Speed ​​Limitation functions can also be used in systems controlled by programmable throat throttle to adjust the Rolantia  .

– Controls the changeable valve timing.

Some engines, such as VTEC engines, have variable valve timing. The engine control unit controls the opening times of the valves in the engine’s combustion cycle. Allows valves to open earlier than at lower speeds. This increases the air flow of the engine control unit to the cylinders, increasing power and contributing to fuel economy.

Eccentric shaftless machines were discovered in 2002 and manufactured in 2009. It has reduced fuel consumption and increased power and torque. Valves are opened by means of a hydraulic pump controlled by the engine control unit.

– Electronic Valve Control

The opening of the intake and exhaust valves is made and tested without fully camshaft-controlled engines. Such engines are capable of operating without the starter motor and are equipped with precise timed electronic ignition and fuel injection, enabling the engine to start. This system is used in hybrid cars. This first type of action is called static start. Static start saves the environment from pollution and increases the efficiency of the vehicle. In short, the valves opened by means of hydraulic pumps are controlled by the ECU. At suction time, the valves can be opened repeatedly depending on the load of the engine. To ensure optimum combustion, the engine control unit decides how much fuel to send. When the load increases with a sudden load change, the ECU will give a lot of fuel to meet this situation and calculate how much fuel it should and should give in the next stroke. Therefore, the response time will be shortened.

To summarize;

The electronic control unit receives information from the sensors, compares this information with the information stored in its memory, executes, interprets, and directs the microprocessor by sending signals to the actuators. The engine control unit tries to optimize the ignition and fuel injection system of the engine in every load and speed condition. For example, in the first start of the morning, the engine transmits the temperature information to the engine water temperature sensor ECU, the ECU looks at the incoming temperature information, compares it with the values ​​in its memory, and interprets that the engine is cold. The ECU opens the throttle slightly by sending a signal to the throttle electric motor, an actuator, increasing the fuel injection time by ordering fuel injectors, which are also activators. This increases the engine idle speed and allows the engine to warm up more quickly.

What are the duties of the Engine Control Unit (ECU)?

1. First and Cold Start;  The amount of fuel is calculated based on engine speed and coolant temperature. At very low temperatures, the spraying time is extended and a rich mixture is obtained. When the engine is warmed, the mixture is leaned by reducing the spraying time.
2. Engine Heating Circuit;  The control unit enriches the mixture depending on the coolant temperature. The mixture, which is enriched in the heating time of the engine, is adjusted by reducing the spray time according to the coolant temperature.
3. Acceleration;  During acceleration, the ECU enhances the mixture with coolant temperature, throttle opening speed, engine speed, throttle opening at the moment of acceleration.

4. Full Power; When the engine is running at full power, the ECU extends the spraying time when the throttle is opened more than two thirds of the throttle opening.
5. Engine Speed ​​Limitation; When the engine speed exceeds the limit value, the ECU interrupts the injection of fuel to prevent it from passing.
6. Deceleration;  During deceleration, the control unit may reduce or completely cut off the fuel injection time in the injector depending on the engine speed, engine coolant temperature and throttle position.
7. Sensor Signal Failure Instantly; There is a safety system that ensures that the engine starts even if one or more of the elements such as engine coolant and air temperature sensors, idling engine, throttle potentiometer, oxygen sensor are faulty.

Memory Units in the Electronic Control Unit Structure:

RAM:  Random Acces Memory
ROM:  Read Only Memory
EPROM:  Erasable Programmable Read Only Memory. Instantaneous data (parameters) from the sensors are also stored in the EPROM.
EEPROM:  Electronically Erasable and Programmable Read Only Memory. The ECU software (program), ie the setting data of the motor, is saved in the EPROM. When the systems are started, for example, the corrected values ​​of the EGR ratio according to the signals from the sensors are stored in the EEPROM.

What is OBD? (On-board Diagnostics)

Vehicle diagnostic device, also known as OBD device, is the system that provides information to the owner or repair technician about the vehicle by connecting to the electronic control unit via the OBD socket of the car. The diagnostic device can provide information about the status of some systems other than the fault information. Since the 1980s version of the in-car computer model, it has improved and its capacity to provide information has increased considerably. The old version of the OBD did not provide details by simply lighting a simple fault lamp. In modern OBD2, real-time information flow is possible and it provides the opportunity to make detailed information about the failures and to make point shot detection. In addition, the resulting failures can be recorded and stored in memory.

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