Engine control units (ECU)

Genesis and application.

The history of electronic engine controllers, known as ECUs (Electronic Control Unit / Engine Control Unit), exemplifies the evolution of automotive technology, driven by the need to increase performance, fuel efficiency and reduce emissions. In the 1960s, the first attempts to introduce electronic control systems in cars began. Initially these were simple systems, mainly used in motor racing. The breakthrough came in 1968 when Volkswagen introduced D-Jetronic, the world's first electronic fuel injection system, designed by Bosch. This was a system that used air pressure and temperature sensors to control fuel injection.

The 1980s saw the development of microprocessors, which became more advanced and accessible, enabling the development of more sophisticated engine control systems. Digital technology allowed more precise control of combustion processes, which helped to improve fuel efficiency and reduce exhaust emissions. During this period, Bosch introduced the Motronic system, integrating fuel injection and ignition control into a single unit.

ECUs became standard on most vehicles in the 1990s and these systems were increasingly integrated, combining functions to control fuel injection, ignition and other aspects of engine operation. The introduction of OBD (On-Board Diagnostics) systems enabled monitoring and diagnosis of engine systems, making servicing and repairs easier. 

ECUs have become extremely sophisticated in the 21st century, integrating control functions for many vehicle subsystems. The introduction of stringent emission standards, such as Euro 4, Euro 5 and then Euro 6, forced carmakers to use even more advanced engine control technologies, including exhaust gas filtration and selective catalytic reduction systems. ECUs began to play a key role in the management of electric drives, batteries and the integration of energy recuperation systems, which was indispensable with the growing popularity of electric and hybrid vehicles.

Today's autonomous cars also use advanced ECUs to manage not only the engine, but also driver assistance and autonomous driving systems. This shows how automotive technology has evolved to meet increasing demands for efficiency, safety and environmental protection. Electronic engine controllers have become an integral part of modern vehicles, enabling increasingly sophisticated control over their operation.

Construction and principle of operation.

An electronic engine controller is often referred to as an engine computer. And there is nothing surprising about this, as in its construction and function it resembles a computer. The operation of all modern internal combustion engines is managed by an electronic control unit. Each successive generation of engine control unit has a more complex architecture and software that performs more and more functions. The controller software implements an engine strategy based on the driver's wishes, while taking into account dozens of instantaneous parameters and sensor feedback signals, as well as a range of correction values related to keeping the exhaust emissions at an appropriate level.

The main tasks of the ECU are:

1. Sensor signal processing: Receives data from sensors, such as temperature, pressure, airflow, crankshaft position sensors, and processes them into information useful for engine management.
2. Fuel injection control: Optimises the amount of fuel and the injection timing into the combustion chambers to ensure efficient and clean combustion.
3. Ignition management (on petrol engines): Controls the ignition timing of the fuel-air mixture to maximise efficiency and minimise exhaust emissions.
4. Exhaust emissions control: Controls exhaust gas recirculation (EGR) systems, catalytic converters and diesel particulate filters (DPF) to reduce emissions.
5. Diagnostics and protection: monitors the condition of the engine and its components, detects faults, records fault codes and initiates protection procedures if necessary.
6. Communication and data exchange with other controllers in the vehicle (ABS/ESP, automatic transmission, comfort, safety modules, etc.).

The central component of the ECU is the processor or microcontroller. This is an integrated circuit that executes the programmes that control the operation of the engine. The processor receives signals from various sensors, processes them according to pre-programmed algorithms and sends the appropriate control signals to the engine's actuators, such as fuel injectors, ignition coils, EGR valve, fuel pressure and boost pressure regulators, etc. 

Controller firmware is a set of programs and algorithms that control engine operation. Firmware is usually developed by the vehicle manufacturer or ECU supplier and is crucial for optimal engine operation, fuel efficiency and meeting emission standards.

One of the functions performed by the engine controller is the engine start lock, the so-called immobiliser. The purpose of this system is to prevent unauthorised persons from starting the engine, thus effectively protecting the vehicle against theft.

The ECU has different types of memory:

1. ROM (Read-Only Memory): Contains the fixed software code (firmware) of the controller.
2. RAM (Random Access Memory): Used to temporarily store data during ECU operation.
3. EEPROM (Electrically Erasable Programmable Read-Only Memory) or Flash Memory: Allows the storage of data that can be modified, such as fuel injection maps or diagnostic settings.

The ECU has numerous inputs and outputs that allow communication with sensors and engine actuators:

1. Analogue inputs: Examples are temperature sensors, intake manifold air pressure, throttle position.
2. Digital inputs: Signals from crankshaft position sensors, camshaft, vehicle speed signals.
3. Digital outputs: Control of fuel injectors, ignition coils, exhaust gas recirculation (EGR) valves.

The ECU communicates with other control units in the vehicle via various communication protocols, such as:

1. CAN (Controller Area Network): A popular communication protocol in vehicles that allows data exchange between different control modules.
2. LIN (Local Interconnect Network): Used to communicate with less critical systems such as comfort systems.
3. FlexRay and MOST (Media Oriented Systems Transport): Used in more advanced communication systems.

The ECU is powered by the vehicle's battery and its circuits must provide stable voltage to all internal components. The ECU supply is also protected against surges and other electrical interference. 

The ECU is equipped with diagnostic functions that monitor engine operation and can detect and report faults. If a problem is detected, the ECU can store the fault code and, if necessary, enter emergency mode to prevent engine damage. The ECU also has protection mechanisms against overvoltage, overheating and other adverse operating conditions.

Remanufacturing process.

Regardless of the scope of the customer's request, our work with the controller starts with its cleaning and external inspection. If necessary, the controller is cleaned, followed by a visual inspection to reveal visible faults such as mechanical damage, leaks, signs of humidity, loose pins, etc. The ability to communicate with the controller is then checked, in order to perform software analysis and check its circuitry. For some controllers, connecting diagnostic tools and programmers requires opening the controller and directly accessing the components mounted on its circuit board. Once the controller has been opened, the condition of the electronic components and their connections can be verified, while identifying and correcting so-called cold solders).

The vast majority of repairs, however, are limited to work on the controller software. Our offer in this area includes, among other things:

1. Controller diagnostics and software analysis,
2. Driver data recovery,
3. Reading the pin code (security code),
4. Resetting (cleaning) the immobiliser,
5. Logging off the controller,
6. Immobiliser synchronisation,
7. Change of VIN number,
8. Cloning the software,
9. Updating the controller software,
10. Programming a new or used controller,
11. Uploading of the original factory software (so-called Virgin),
12. Deactivation of the exhaust gas recirculation system,
13. Permanent deactivation of the Start/Stop system,
14. Switching off the swirl flaps,
15. And much more...

Causes and types of damage

The most common symptoms of engine controller failure are:

1. Unable to start the engine or the engine stalls moments after starting.
2. Correct engine operation dependent on ambient temperature and/or humidity.
3. Uneven engine operation.
4. No response to the accelerator pedal.
5. Lack of communication.
6. Current values cannot be read.
7. Failure to read error codes.
8. Checksum error.
9. CAN BUS faults.
10. Persistent errors that cannot be erased.

The most common electronic engine control unit (ECU) failures are:

1. Corrosion of the interior and contacts - moisture and water.
2. Mechanical damage - vibrations, sudden overloading.
3. Faults in electronic components and connections – too high temperature, humidity, natural aging of components, unstable power supply (sudden overvoltage or voltage drop).