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An Engine Control Unit (ECU) also known as an Engine Control Module (ECM) or Powertrain Control Unit/Module (PCU, PCM) if it controls both an engine and a transmission, is an electronic control unit which controls various aspects of an internal combustion engine's operation. The most simple ECUs simply control the quantity of fuel injected into each cylinder each engine cycle. More advanced ECUs found on most modern cars also control the ignition timing, Variable Cam Timing (VCT), the level of boost maintained by the turbocharger (in turbocharged cars), and control other peripherals. In automotive electronics, an electronic control unit (ECU) is an embedded microcomputer that controls one or more of the electrical subsystems in a vehicle. ...
The internal combustion engine is an engine in which the burning of a fuel occurs in a confined space called a combustion chamber. ...
Ignition timing in an internal combustion engine is the process of setting the time that a spark will occur in the combustion chamber (during the power stroke) relative to piston position and crankshaft angular velocity. ...
Variable Cam Timing (VCT) is an automobile variable valve timing technology developed by Ford. ...
Air foil bearing-supported turbocharger cutaway made by Mohawk Innovative Technology Inc. ...
ECUs determine the quantity of fuel, ignition timing and other parameters by monitoring the engine through sensors. These can include, MAP sensor, throttle position sensor, air temperature sensor, engine coolant temperature sensor and many others. A MAP Sensor (manifold absolute pressure) is a sensor used as part of an internal combustion engines electronic control system. ...
To meet Wikipedias quality standards and make it more accessible to a general audience, this article may require cleanup. ...
Before ECUs most engine parameters were fixed. The quantity of fuel per cylinder per engine cycle was determined by a Carburetor. Bendix-Technico (Stromberg) 1-barrel downdraft carburetor model BXUV-3, with nomenclature The carburetor, carburettor, or carburetter (see spelling differences), also called carb (in North America) or carbie (chiefly in Australia) for short, is a device that blends air and fuel for an internal combustion engine. ...
ECU Operation
Control of Fuel Injection For an engine with fuel injection, an ECU will determine the quantity of fuel to inject based on a number of parameters. If the throttle pedal is pressed further down, the ECU will inject more fuel. If the engine has not warmed up yet, more fuel will be injected (causing the engine to run slightly 'rich' until the engine warms up). // Fuel injection is a means of metering fuel into an internal combustion engine. ...
Control of Ignition Timing A spark ignition engine requires a spark to initiate combustion in the combustion chamber. An ECU can adjust the exact timing of the spark (called ignition timing) to provide better power and economy. If the ECU detects knock, a condition which is potentially destructive to engines, it can delay (retard) the timing of the spark to prevent this. The term spark-ignition is normally used to refer to internal combustion engines where the fuel-air mixture is ignited with a spark. ...
Ignition timing in an internal combustion engine is the process of setting the time that a spark will occur in the combustion chamber (during the power stroke) relative to piston position and crankshaft angular velocity. ...
Knocking (also called pinking or pinging)— colloquially detonation—in internal combustion engines occurs when air/fuel mixture in the cylinder has been ignited by the spark plug and the smooth burning is interrupted by the unburned mixture in the combustion chamber exploding before the flame front can reach it. ...
Control of Variable Cam Timing Some engines have Variable Cam Timing. In such an engine, the ECU controls the time in the engine cycle at which the valves open. The valves are usually opened later at higher speed than at lower speed. This can optimise the flow of air into the cylinder, increasing power and economy. Variable Cam Timing (VCT) is an automobile variable valve timing technology developed by Ford. ...
Programmable ECUs A special category of ECUs are those which are programmable. These units do not have a fixed behavior, but can be reprogrammed by the user.
Programmable ECUs are required where significant aftermarket modifications have been made to a vehicles engine. Examples include, adding or changing of turbocharger, adding or changing of intercooler, changing of exhaust system, conversion to run on alternative fuel. As a consequence of these changes, the old ECU may not provide appropriate control for the new configuration. Air foil bearing-supported turbocharger cutaway made by Mohawk Innovative Technology Inc. ...
It has been suggested that Front mounted intercooler, Top mounted intercooler and Charge cooler be merged into this article or section. ...
The word exhaust can mean:- A verb meaning tire out, as in After the long gallop, his horse was exhausted. ...
This article or section is in need of attention from an expert on the subject. ...
In these situations, a programmable ECU can be wired in. These can be programmed/mapped while the engine is running by connecting a laptop to it using a serial or USB cable. A MacBook A laptop computer, or simply laptop (also notebook computer or notebook), is a small mobile computer, which usually weighs 2. ...
Note: USB may also mean upper sideband in radio. ...
For example the programmable ECU may control the amount of fuel to be injected into each cylinder. This varies depending on the engine's RPM and the position of the gas pedal (or the manifold air pressure). The engine tuner can adjust this by bringing up a spreadsheet-like page on the laptop where each cell represents an intersection between a specific RPM value and a gas pedal position (or the throttle position, as it is called). In this cell a number corresponding to the amount of fuel to be injected is entered. // Fuel injection is a means of metering fuel into an internal combustion engine. ...
A MAP Sensor (manifold absolute pressure) is a sensor used as part of an internal combustion engines electronic control system. ...
Screenshot of a spreadsheet made with OpenOffice. ...
To meet Wikipedias quality standards and make it more accessible to a general audience, this article may require cleanup. ...
By modifying these values while monitoring the exhausts using a wide band lambda probe to see if the engine runs rich or lean, the tuner can find the optimal amount of fuel to inject to the engine at every different combination of RPM and throttle position. This process is often carried out at a dynamometer, giving the tuner a controlled environment to work in. An automotive lambda probe, also known as a lambda sensor, O2 sensor, oxygen sensor, lambda sond or EGO (exhaust gas oxygen) sensor, is a small sensor inserted into the exhaust system of a petrol engine to measure the volume of oxygen (O2) remaining in the exhaust gas to allow an...
A dynamometer, or dyno for short, is a machine used to measure torque and rotational speed (rpm) from which power produced by an engine, motor or other rotating prime mover can be calculated. ...
Other parameters that are often mappable are:
- Ignition : Defines when the spark plug should fire for a cylinder
- Rev limit : Defines the max RPM that the engine is allowed to rev to. After this fuel and/or ignition is cut.
- Water temperature correction : Allows for additional fuel to be added when the engine is cold (choke).
- Transient fueling : Tells the ECU to add a specific amount of fuel when throttle is applied.
- Low fuel pressure modifier : Tells the ECU to increase the injector fire time to compensate for a loss of fuel pressure.
- Closed loop lambda : Lets the ECU monitor a permanently installed lambda probe and modify the fueling to achieve stoichiometric (ideal) combustion.
Some of the more advanced race ECUs include functionality such as launch control, limiting the power of the engine in first gear to avoid burnouts. Other examples of advanced functions are: This article or section should include material from Spark gap A spark plug is an electrical device that fits into the cylinder head of some internal combustion engines and ignites compressed aerosol gasoline by means of an electric spark. ...
Revolutions per minute (abbreviated rpm, RPM, r/min, or min-1) is a unit of frequency, commonly used to measure rotational speed, in particular in the case of rotation around a fixed axis. ...
In an engine, the throttle is the mechanism by which the engines power is increased or decreased. ...
An oxygen sensor is an electronic device that measures the proportion of oxygen in the gas or liquid being analyzed. ...
In chemistry, stoichiometry is the study of the combination of elements in chemical reactions. ...
Launch control refers to an electronic device that is used to assist a Formula 1 driver in the very moment of the start of a race. ...
- Waste gate control : Sets up the behavior of a turbo waste gate, controlling boost.
- Banked injection : Sets up the behavior of double injectors per cylinder, used to get a finer fuel injection control and atomization over a wide RPM range.
- Variable cam timing : Tells the CPU how to control variable intake and exhaust cams.
- Gear control : Tells the ECU to cut ignition during (sequential gearbox) upshifts or blip the throttle during downshifts.
A race ECU is often equipped with a data logger recording all sensors for later analysis using special software in a PC. This can be useful to track down engine stalls, misfires or other undesired behaviors during a race by downloading the log data and looking for anomalies after the event. The data logger usually has a capacity between 0.5 and 16 Mbytes. A wastegate is a valve that diverts exhaust gases away from the turbine wheel in a turbocharger. ...
The word Boost can refer to a number of things: Look up boost in Wiktionary, the free dictionary. ...
Variable Cam Timing (VCT) is an automobile variable valve timing technology developed by Ford. ...
Semi-automatic transmission, or also known as clutchless manual transmission or automated manual transmission, is a system which uses electronic sensors, processors and actuators to do gear shifts on the command of the driver. ...
In order to communicate with the driver, a race ECU can often be connected to a "data stack", which is a simple dash board presenting the driver with the current RPM, speed and other basic engine data. These race stacks, which are almost always digital, talk to the ECU using one of several proprietary protocols running over RS232, CANbus or ethernet. Ethernet is a large and diverse family of frame-based computer networking technologies for local area networks (LANs). ...
ECU 'flashing'
 Example reflash tuning software Many recent (around 1996 or newer) cars use OBD-II ECUs that are sometimes capable of having their programming changed through the OBD port. Automotive enthusiasts with modern cars take advantage of this technology when tuning their engines. Rather than use an entire new engine management system, one can use the appropriate software to adjust the factory equipped computer. By doing so, it is possible to retain all stock functions and wiring while using a custom tuned program. This should not be confused with "chip tuning", where the owner has ECU ROM physically replaced with a different one -- no hardware modification is (usually) involved with flashing ECUs, although special equipment is required. Image File history File links Download high-resolution version (1216x902, 140 KB)[edit] Summary [Ecuedit] editor with a USDM 2004 Subaru WRX STI ROM opened. ...
Image File history File links Download high-resolution version (1216x902, 140 KB)[edit] Summary [Ecuedit] editor with a USDM 2004 Subaru WRX STI ROM opened. ...
OBD-II (OnBoard Diagnostics version 2) is a common hardware diagnostics interface that is present on all cars sold in the United States after 1996. ...
Factory engine management systems often have similar controls as aftermarket units intended for racing, such as 3-dimensional timing and fuel control maps. They generally do not have the ability to control extra ancillary devices, such as variable valve timing if the factory vehicle was a fixed geometry camshaft or boost control if the factory car was not turbocharged. Variable valve timing, or VVT, is a generic term for an automobile piston engine technology. ...
Boost control is the principle of controlling the boost level produced in the intake manifold of a turbocharged or supercharged engine by affecting the air pressure delivered to the pneumatic and mechanical wastegate actuator. ...
History
Early ECUs Early ECU designs were based more on analogue computer circuitry. It was not until around 1987 that digital electronics and embedded microprocessor systems became fast enough to process engine parameters in real time. The first such systems were introduced into racing engines such as those used for Formula One, but it was not long before these found their way into everyday cars. An analog computer (American English) or analogue computer (British English) is a form of computer using electronic or mechanical phenomena to model the problem being solved by using one kind of physical quantity to represent another. ...
1987 (MCMLXXXVII) was a common year starting on Thursday of the Gregorian calendar. ...
A digital system is one that uses discrete values (often electrical voltages), especially those representable as binary numbers, or non-numeric symbols such as letters or icons, for input, processing, transmission, storage, or display, rather than a continuous spectrum of values (ie, as in an analog system). ...
A router, an example of an embedded system. ...
Formula One - Wikipedia, the free encyclopedia /**/ @import /skins-1. ...
Karl Benzs Velo (vélo means bicycle in French) model (1894) - entered into the first automobile race 2005 MINI Cooper S. An automobile (also motor car or simply car) is a wheeled passenger vehicle that carries its own motor. ...
Hybrid digital designs A hybrid digital design was popular in the mid-'80s. This used analogue techniques to measure and process input parameters from the engine, then used a look-up table stored in a digital ROM chip to yield precomputed output values. Later systems compute these outputs dynamically. The ROM type of system is amenable to tuning if one knows the system well. The disadvantage of such systems is that the precomputed values are only optimal for an idealised, new engine. As the engine wears, the system is less able to compensate than a CPU based system. In computer science, a lookup table is a data structure, usually an array or associative array, used to replace a runtime computation with a simpler lookup operation. ...
Read-only memory (ROM) is a class of storage media used in computers and other electronic devices. ...
Engine tuning or engine building is the adjustment, modification or design of internal combustion engines to yield more performance, either in terms of power output or economy. ...
Sophisticated engine management systems receive inputs from other sources, and control other parts of the engine; for instance, some variable valve timing systems are electronically controlled, and turbocharger wastegates can also be managed. They also may communicate with transmission control units or directly interface electronically-controlled automatic transmissions, traction control systems, and the like. The Controller Area Network or CAN bus automotive network is often used to achieve communication between these devices. Variable valve timing, or VVT, is a generic term for an automobile piston engine technology. ...
Air foil bearing-supported turbocharger cutaway made by Mohawk Innovative Technology Inc. ...
A Transmission Control Unit is a device that controls modern electronic automatic transmissions. ...
An automatic transmission is an automobile gearbox that can change gear ratios automatically as the vehicle moves, thus freeing the driver from having to shift gears manually. ...
Traction control systems, on current production vehicles, are typically (but not necessarily) electro-hydraulic systems designed to prevent loss of traction (and therefore the control of the vehicle) when excessive throttle or steering is applied by the driver. ...
Controller Area Network (CAN) is a multicast shared, differential serial bus standard, originally developed in the 1980s by Robert Bosch GmbH, for connecting electronic control units (ECUs). ...
Modern ECUs Modern ECUs use a microprocessor which can process the inputs from the engine sensors in real time. An electronic control unit contains the hardware and software (firmware). The hardware consists of electronic components on a printed circuit board (PCB). The main component on this circuit board is a microcontroller chip (CPU). The software is stored in the microcontroller or other chips on the PCB, typically in EPROMs or flash memory so the CPU can be re-programmed by uploading updated code. This is also referred to as an (electronic) Engine Management System (EMS). A microprocessor (sometimes abbreviated µP) is a programmable digital electronic component that incorporates the functions of a central processing unit (CPU) on a single semiconducting integrated circuit (IC). ...
It has been suggested that Real-time computing be merged into this article or section. ...
In computing, firmware is software that is embedded in a hardware device. ...
Close-up photo of one side of a motherboard PCB, showing conductive traces, vias and solder points for through-hole components on the opposite side. ...
CPU can stand for: in computing: Central processing unit in journalism: Commonwealth Press Union in law enforcement: Crime prevention unit in software: Critical patch update, a type of software patch distributed by Oracle Corporation in Macleans College is often known as Ash Lim. ...
EPROM. The small quartz window admits UV light during erasure. ...
A USB flash drive. ...
Other applications Such systems are used for many internal combustion engines in other applications. In aeronautical applications, the systems are known as "FADECs" (Full Authority Digital Engine Controls). This kind of electronic control is less common in piston-engined aeroplanes than in automobiles, because of the large costs of certifying parts for aviation use, relatively small demand, and the consequent stagnation of technological innovation in this market. Also, a carburated engine with magneto ignition and a gravity feed fuel system does not require any electrical power to run, which is a safety bonus. FADEC is the acronym for Full Authority Digital Engine Control. ...
An Air France Boeing 777, a modern passenger jet. ...
Bendix-Technico (Stromberg) 1-barrel downdraft carburetor model BXUV-3, with nomenclature The carburetor, carburettor, or carburetter (see spelling differences), also called carb (in North America) or carbie (chiefly in Australia) for short, is a device that blends air and fuel for an internal combustion engine. ...
A magneto provides pulses of electrical power to the spark plugs in some gasoline -powered internal combustion engines where batteries are not available, most commonly those in 2-stroke and 4-stroke engines used in small motorcycles, lawnmowers and chainsaws, as well as in most small aircraft and some racing...
See also An air flow meter, also know as air consumption meter, is a device that measures how much air is flowing through a tube. ...
A Malfunction Indicator Lamp, this one labeled Service Engine Soon. A Malfunction Indicator Lamp (MIL) is an indicator of the internal status of a car engine. ...
External links Manufacturers of Aftermarket ECUs Open source engine management systems: MegaSquirt is an aftermarket electronic fuel injection (EFI) controller designed to be used with a wide range of internal combustion engines. ...
- MegaSquirt Electronic Fuel Injection Computer
- CarDAQ-plus J2534 pass-thru hardware device
- Openecu tools for reflashing, logging, and tuning Subaru and Mitsubishi cars
DIY engine management systems: - VEMS group
- VEMS genboard hardware versions up to 3.3 is somewhat limitedly open. Firmware has license restrictions see the Genboard Public Licence. Source code is available to registered developers only and modifications must be send back to authors.
http://www.vems.hu/wiki/index.php?page=GenBoard%2FUnderDevelopment%2FFirmwareChanges |
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