Engine control unit - Wikipedia, the free encyclopedia. An engine control unit (ECU) 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 (called lookup tables), and adjusting the engine actuators accordingly. Before ECUs, air- fuel mixture, ignition timing, and idle speed were mechanically set and dynamically controlled by mechanical and pneumatic means. Working of ECU. The ECU determines the amount of fuel to inject based on a number of sensor readings. Oxygen sensors tell the ECU whether the engine is running rich (too much fuel/too little oxygen) or running lean (too much oxygen/too little fuel) as compared to ideal conditions (known as stoichiometric). The throttle position sensors tell the ECU how far the throttle plate is opened when you press the accelerator. The mass air flow sensor measures the amount of air flowing into the engine through the throttle plate. The engine coolant temperature sensor measures whether the engine is warmed up or cool. The engine RPM is monitored by the crankshaft position sensor which plays a primary role in the engine timing functions for fuel injection, spark events, and valve timing. Idle speed is controlled by a programmable throttle stop or an idle air bypass control stepper motor. Early carburetor- based systems used a programmable throttle stop using a bidirectional DC motor. Early Throttle body injection (TBI) systems used an idle air control stepper motor. Effective idle speed control must anticipate the engine load at idle. A full authority throttle control system may be used to control idle speed, provide cruise control functions and top speed limitation. Free ecu remapping software social advice Users interested in Free ecu remapping software generally download. Telephone Features Programming Guide. Time-saving features. Pages dealing with the time remapping effect in Premiere Pro. Find great deals on eBay for ECU Remapping Software in Vehicle Diagnostic Tools and Equipment. Shop with confidence. Control of variable valve timing. In such an engine, the ECU controls the time in the engine cycle at which the valves open. The valves are usually opened sooner at higher speed than at lower speed. This can optimize the flow of air into the cylinder, increasing power and fuel economy. Electronic valve control. Such a static- start engine would provide the efficiency and pollution- reduction improvements of a mild hybrid- electric drive, but without the expense and complexity of an oversized starter motor. Their Multiair engines use electronic valve control which dramatically improve torque and horsepower, while reducing fuel consumption as much as 1. Basically, the valves are opened by hydraulic pumps, which are operated by the ECU. The valves can open several times per intake stroke, based on engine load. Currently warp stabilizer and time remapping cannot be applied at the same time. UK number 1 ECU remapping and diesel tuning specialists. Expert advice on all your chip tuning and engine performance needs. Time-remapping is one of the program’s most versatile and powerful features. It enables a user to loop a clip or vary its playback speed or. The ECU then decides how much fuel should be injected to optimize combustion. At steady load conditions, the valve opens, fuel is injected, and the valve closes. Under a sudden increase in throttle, the valve opens in the same intake stroke and a greater amount of fuel is injected. This allows immediate acceleration. For the next stroke, the ECU calculates engine load at the new, higher RPM, and decides how to open the valve: early or late, wide- open or half- open. The optimal opening and timing are always reached and combustion is as precise as possible. This, of course, is impossible with a normal camshaft, which opens the valve for the whole intake period, and always to full lift. The elimination of cams, lifters, rockers, and timing set reduces not only weight and bulk, but also friction. A significant portion of the power that an engine actually produces is used up just driving the valve train, compressing all those valve springs thousands of times a minute. Once more fully developed, electronic valve operation will yield even more benefits. Cylinder deactivation, for instance, could be made much more fuel efficient if the intake valve could be opened on every downstroke and the exhaust valve opened on every upstroke of the deactivated cylinder or . Another even more significant advancement will be the elimination of the conventional throttle. When a car is run at part throttle, this interruption in the airflow causes excess vacuum, which causes the engine to use up valuable energy acting as a vacuum pump. BMW attempted to get around this on their V- 1. M5, which had individual throttle butterflies for each cylinder, placed just before the intake valves. With electronic valve operation, it will be possible to control engine speed by regulating valve lift. At part throttle, when less air and gas are needed, the valve lift would not be as great. Full throttle is achieved when the gas pedal is depressed, sending an electronic signal to the ECU, which in turn regulates the lift of each valve event, and opens it all the way up. Programmable E. C. U. s. These units do not have a fixed behavior and can be reprogrammed by the user. Programmable E. C. U. s are required where significant aftermarket modifications have been made to a vehicle's engine. Examples include adding or changing of a turbocharger, adding or changing of an intercooler, changing of the exhaust system or a conversion to run on alternative fuel. As a consequence of these changes, the old ECU may not provide appropriate control for the new configuration. In these situations, a programmable ECU can be wired in. These can be programmed/mapped with a laptop connected using a serial or USB cable, while the engine is running. 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 accelerator 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 an accelerator 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. This spreadsheet is often referred to as a fuel table or fuel map. 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 engine dynamometer gives a more precise calibration for racing applications. Tuners often utilize a chassis dynamometer for street and other high performance applications. Other parameters that are often mappable are: Ignition Timing: Defines at what point in the engine cycle the spark plug should fire for each cylinder. Modern systems allow for individual trim on each cylinder for per- cylinder optimization of the ignition timing. Rev. After this fuel and/or ignition is cut. Some vehicles have a . This is referred to as . This is often the stoichiometric (ideal) air fuel ratio, which on traditional petrol (gasoline) powered vehicles this air: fuel ratio is 1. This can also be a much richer ratio for when the engine is under high load, or possibly a leaner ratio for when the engine is operating under low load cruise conditions for maximum fuel efficiency. Some of the more advanced standalone/race E. C. U. s include functionality such as launch control, operating as a rev limiter while the car is at the starting line to keep the engine revs in a 'sweet spot', waiting for the clutch to be released to launch the car as quickly and efficiently as possible. Other examples of advanced functions are: Waste gate control: Controls the behavior of a turbocharger's waste gate, controlling boost. This can be mapped to command a specific duty cycle on the valve, or can use a P. I. D. An example being the use of small injectors for smooth idle and low load conditions, and a second, larger set of injectors that are 'staged in' at higher loads, such as when the turbo boost climbs above a set point. Variable cam timing: Allows for control variable intake and exhaust cams (V. V. T), mapping the exact advance/retard curve positioning the camshafts for maximum benefit at all load/rpm positions in the map. This functionality is often used to optimize power output at high load/R. P. M. s, and to maximize fuel efficiency and emissions as lower loads/R. P. M. s. Gear control: Tells the ECU to cut ignition during (sequential gearbox) up shifts or blip the throttle during downshifts. Anti- lag: Is an option which is provided by racing E. C. U. s only for turbocharged vehicles. When it is on, it changes the ignition timing to late, providing a fast charge of the turbocharger. When anti- lag is on, gunshot sounds and flames come from the exhaust, indicating extreme temperatures and pressures. 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. In order to communicate with the driver, a race ECU can often be connected to a . These race stacks, which are almost always digital, talk to the ECU using one of several proprietary protocols running over RS2. CANbus, connecting to the DLC connector (Data Link Connector) usually located on the underside of the dash, inline with the steering wheel. History. However, it had some problems: it would surge the engine, making close formation flying of the Fw 1. Focke- Wulf Fw 1. Wurger), a single- engine single- seat German fighter aircraft, somewhat difficult, and at first it switched supercharger gears harshly and at random, which could throw the aircraft into an extremely dangerous stall. Hybrid digital designs. This used analog techniques to measure and process input parameters from the engine, then used a lookup table stored in a digital ROM chip to yield precomputed output values. Later systems compute these outputs dynamically.
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