An electronic control unit (ECU), also known as an electronic control module (ECM), is an embedded system in automotive electronics that controls one or more of the electrical systems or subsystems in a car or other motor vehicle.
Modern vehicles have many ECUs, and these can include some or all of the following: engine control module (ECM), powertrain control module (PCM), transmission control module (TCM), brake control module (BCM or EBCM), central control module (CCM), central timing module (CTM), general electronic module (GEM), body control module (BCM), and suspension control module (SCM). These ECUs together are sometimes referred to collectively as the car's computer though technically they are all separate computers, not a single one. Sometimes an assembly incorporates several individual control modules (a PCM often controls both the engine and the transmission). [1]
Some modern motor vehicles have up to 150 ECUs. [2] Embedded software in ECUs continues to increase in line count, complexity, and sophistication. [3] Managing the increasing complexity and number of ECUs in a vehicle has become a key challenge for original equipment manufacturers (OEMs).
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The development of an ECU involves both hardware and software required to perform the functions expected from that particular module. Automotive ECU's are being developed following the V-model. [1] Recently the trend is to dedicate a significant amount of time and effort to develop safe modules by following standards like ISO 26262. [5] It is rare that a module is developed fully from scratch. The design is generally iterative and improvements are made to both the hardware and software. The development of most ECUs is carried out by Tier 1 suppliers based on specifications provided by the OEM[ citation needed ].
As part of the development cycle, manufacturers perform detailed FMEAs and other failure analyses to catch failure modes that can lead to unsafe conditions or driver annoyance. Extensive testing and validation activities are carried out as part of the Production part approval process to gain the confidence of the hardware and software. On-board diagnostics or OBD help provide specific data related to which system or component failed or caused a failure during run time and help perform repairs.
Some people may wish to modify their ECU so as to be able to add or change functionality. However modern ECUs come equipped with protection locks to prevent users from modifying the circuit or exchange chips. The protection locks are a form of digital rights management (DRM), the circumventing of which is illegal in certain jurisdictions. In the United States for example, the DMCA criminalizes circumvention of DRM, [6] though an exemption does apply that allows circumvention the owner of a motorized land vehicle if it is required to allow diagnosis, repair or lawful modification (ie. that does not violate applicable law such as emissions regulations). [7]
An embedded system is a computer system—a combination of a computer processor, computer memory, and input/output peripheral devices—that has a dedicated function within a larger mechanical or electronic system. It is embedded as part of a complete device often including electrical or electronic hardware and mechanical parts. Because an embedded system typically controls physical operations of the machine that it is embedded within, it often has real-time computing constraints. Embedded systems control many devices in common use today. In 2009, it was estimated that ninety-eight percent of all microprocessors manufactured were used in embedded systems.
A Controller Area Network is a vehicle bus standard designed to allow microcontrollers and devices to communicate with each other's applications without a host computer. It is a message-based protocol, designed originally for multiplex electrical wiring within automobiles to save on copper, but it can also be used in many other contexts. For each device, the data in a frame is transmitted serially but in such a way that if more than one device transmits at the same time, the highest priority device can continue while the others back off. Frames are received by all devices, including by the transmitting device.
Automotive engineering, along with aerospace engineering and naval architecture, is a branch of vehicle engineering, incorporating elements of mechanical, electrical, electronic, software, and safety engineering as applied to the design, manufacture and operation of motorcycles, automobiles, and trucks and their respective engineering subsystems. It also includes modification of vehicles. Manufacturing domain deals with the creation and assembling the whole parts of automobiles is also included in it. The automotive engineering field is research intensive and involves direct application of mathematical models and formulas. The study of automotive engineering is to design, develop, fabricate, and test vehicles or vehicle components from the concept stage to production stage. Production, development, and manufacturing are the three major functions in this field.
A traction control system (TCS), also known as ASR, is typically a secondary function of the electronic stability control (ESC) on production motor vehicles, designed to prevent loss of traction of the driven road wheels. TCS is activated when throttle input and engine power and torque transfer are mismatched to the road surface conditions.
A vehicle bus is a specialized internal communications network that interconnects components inside a vehicle. In electronics, a bus is simply a device that connects multiple electrical or electronic devices together. Special requirements for vehicle control such as assurance of message delivery, of non-conflicting messages, of minimum time of delivery, of low cost, and of EMF noise resilience, as well as redundant routing and other characteristics mandate the use of less common networking protocols. Protocols include Controller Area Network (CAN), Local Interconnect Network (LIN) and others. Conventional computer networking technologies are rarely used, except in aircraft, where implementations of the ARINC 664 such as the Avionics Full-Duplex Switched Ethernet are used. Aircraft that use AFDX include the B787, the A400M and the A380. Trains commonly use Ethernet Consist Network (ECN). All cars sold in the United States since 1996 are required to have an On-Board Diagnostics connector, for access to the car's electronic controllers.
Electronic throttle control (ETC) is an automobile technology which electronically "connects" the accelerator pedal to the throttle, replacing a mechanical linkage. A typical ETC system consists of three major components: (i) an accelerator pedal module, (ii) a throttle valve that can be opened and closed by an electric motor, and (iii) a powertrain or engine control module. The ECM is a type of electronic control unit (ECU), which is an embedded system that employs software to determine the required throttle position by calculations from data measured by other sensors, including the accelerator pedal position sensors, engine speed sensor, vehicle speed sensor, and cruise control switches. The electric motor is then used to open the throttle valve to the desired angle via a closed-loop control algorithm within the ECM.
Drive by wire or DbW technology in the automotive industry is the use of electrical or electro-mechanical systems for performing vehicle functions traditionally achieved by mechanical linkages. Common examples include power steering, electronic throttle control and brake-by-wire. These technologies replace the traditional mechanical control systems with electronic control systems using electromechanical actuators and human–machine interfaces such as pedal and steering feel emulators. Components such as the steering column, intermediate shafts, pumps, hoses, belts, coolers and vacuum servos and master cylinders are eliminated from the vehicle. This is similar to the fly-by-wire systems used widely in the aviation industry. Safety standards for drive-by-wire are specified by the ISO 26262 standard level D.
On-board diagnostics (OBD) is a term referring to a vehicle's self-diagnostic and reporting capability. OBD systems give the vehicle owner or repair technician access to the status of the various vehicle sub-systems. The amount of diagnostic information available via OBD has varied widely since its introduction in the early 1980s versions of on-board vehicle computers. Early versions of OBD would simply illuminate a malfunction indicator light (MIL) or "idiot light" if a problem was detected, but would not provide any information as to the nature of the problem. Modern OBD implementations use a standardized digital communications port to provide real-time data in addition to a standardized series of diagnostic trouble codes, or DTCs, which allow a person to rapidly identify and remedy malfunctions within the vehicle.
An engine control unit (ECU), also commonly called an engine control module (ECM), is a type of electronic control unit that controls a series of actuators on an internal combustion engine to ensure optimal engine performance. It does this by reading values from a multitude of sensors within the engine bay, interpreting the data using multidimensional performance maps, and adjusting the engine actuators. Before ECUs, air–fuel mixture, ignition timing, and idle speed were mechanically set and dynamically controlled by mechanical and pneumatic means.
A transmission control unit (TCU), also known as a transmission control module (TCM), or a gearbox control unit (GCU), is a type of automotive ECU that is used to control electronic automatic transmissions. Similar systems are used in conjunction with various semi-automatic transmissions, purely for clutch automation and actuation. A TCU in a modern automatic transmission generally uses sensors from the vehicle, as well as data provided by the engine control unit (ECU), to calculate how and when to change gears in the vehicle for optimum performance, fuel economy and shift quality.
A power-train control module, abbreviated PCM, is an automotive component, a control unit, used on motor vehicles. It is generally a combined controller consisting of the engine control unit (ECU) and the transmission control unit (TCU). On some cars, such as many Chryslers, there are multiple computers: the PCM, the TCU, and the Body Control Module (BCM), for a total of three separate computers. These automotive computers are generally very reliable. The PCM commonly controls more than 100 factors in a car or truck. There are many hundreds of error codes that can occur, which indicates that some subsection of the car is experiencing a problem. When one of these errors occurs, usually it will turn on the "check engine" light on the dashboard. The PCM is one of potentially several on-board computers, or essentially the "brain" of the engine control system.
Hardware-in-the-loop (HIL) simulation, HWIL, or HITL, is a technique that is used in the development and testing of complex real-time embedded systems. HIL simulation provides an effective testing platform by adding the complexity of the process-actuator system, known as a plant, to the test platform. The complexity of the plant under control is included in testing and development by adding a mathematical representation of all related dynamic systems. These mathematical representations are referred to as the "plant simulation". The embedded system to be tested interacts with this plant simulation.
In the automotive industry, brake-by-wire technology is the ability to control brakes through electrical means. It can be designed to supplement ordinary service brakes or it can be a standalone brake system.
Electronic Diesel Control is a diesel engine fuel injection control system for the precise metering and delivery of fuel into the combustion chamber of modern diesel engines used in trucks and cars.
Automotive electronics are electronic systems used in vehicles, including engine management, ignition, radio, carputers, telematics, in-car entertainment systems, and others. Ignition, engine and transmission electronics are also found in trucks, motorcycles, off-road vehicles, and other internal combustion powered machinery such as forklifts, tractors and excavators. Related elements for control of relevant electrical systems are also found on hybrid vehicles and electric cars.
Vector Informatik develops software tools and components for networking of electronic systems based on the serial bus systems CAN, LIN, FlexRay, MOST, Ethernet, AFDX, ARINC 429, and SAE J1708 as well as on CAN-based protocols such as SAE J1939, SAE J1587, ISO 11783, NMEA 2000, ARINC 825, CANaerospace, CANopen and more. The headquarters of the company Vector Informatik GmbH is in Stuttgart, Germany. Subsidiaries include Braunschweig, Munich, Hamburg, Regensburg along with international subsidiaries in Brazil, China, France, Italy, England, India, Japan, South Korea, Austria, Sweden, and the United States. Vector Informatik also includes Vector Consulting Services GmbH, a consulting firm specializing in the optimization of technical product development. Altogether, these companies are referred to as the Vector Group.
The ETAS Group is a German company which designs tools for the development of embedded systems for the automotive industry and other sectors of the embedded industry. ETAS is 100-percent subsidiary of Robert Bosch GmbH.
In automotive electronics, body control module or 'body computer' is a generic term for an electronic control unit responsible for monitoring and controlling various electronic accessories in a vehicle's body. Typically in a car the BCM controls the power windows, power mirrors, air conditioning, immobilizer system, central locking, etc. The BCM communicates with other on-board computers via the car's vehicle bus, and its main application is controlling load drivers – actuating relays that in turn perform actions in the vehicle such as locking the doors, flashing the turn signals, or dimming the interior lighting.
Unified Diagnostic Services (UDS) is a diagnostic communication protocol used in electronic control units (ECUs) within automotive electronics, which is specified in the ISO 14229-1. It is derived from ISO 14230-3 (KWP2000) and the now obsolete ISO 15765-3. 'Unified' in this context means that it is an international and not a company-specific standard. By now this communication protocol is used in all new ECUs made by Tier 1 suppliers of Original Equipment Manufacturer (OEM), and is incorporated into other standards, such as AUTOSAR. The ECUs in modern vehicles control nearly all functions, including electronic fuel injection (EFI), engine control, the transmission, anti-lock braking system, door locks, braking, window operation, and more.
Automotive security refers to the branch of computer security focused on the cyber risks related to the automotive context. The increasingly high number of ECUs in vehicles and, alongside, the implementation of multiple different means of communication from and towards the vehicle in a remote and wireless manner led to the necessity of a branch of cybersecurity dedicated to the threats associated with vehicles. Not to be confused with automotive safety.