1. Introduction
ECU
ECU (Electronic Control Unit) the electronic control unit, also known as “trip computer”, “car computer” and the like. From the use of perspective is a vehicle for computer controller, also known as vehicle-specific microcontroller. It ordinary microcontroller as large scale integration by the microprocessor (CPU), a memory (ROM ,, RAM), an input / output interface (I / O), analog to digital converter (A / D) and shaping, driving, etc. circuit.
2, and the role of the working environment
Usually the ECU voltage operating range (voltage stabilizing means at the internal key) in 6.5-16V, the operating current 0.015-0.1A, operating temperature of minus 40-80 degrees. 1000Hz less able to withstand the vibration, thus the probability of damage is very small ECU, the ECU is a core part of the CPU, which has a function of computing and control, when the engine is running, it is collecting signals from the sensors, calculates, and operation result into a control signal to control the controlled object of work. It also exercise control memory (ROM ,, RAM), an input / output interface (I / O) and the other external circuit; stored in program memory ROM is precisely calculated and experimental data taken on the basis of a large number, the program inherent when the engine is operating, constantly calculating and comparing the signal acquisition to each sensor. The result of the comparison calculation and control of a number of parameters controlling the ignition of the engine, air-fuel ratio, idle, exhaust gas recirculation and the like. It is also self-diagnostics and protection function, when the system failure, it can automatically record code and fault protection using an alternative procedure to read from said program to maintain the inherent operation of the engine in the RAM, the automobile-opening to the repair shop.
3, adaptive procedure
RAM will keep your driving record data, becoming ECU learning program to provide the best control state to adapt to your driving habits, this program is also called adaptive program. However, because it is stored in the RAM, the same code as an error, but to remove a battery loses power, all data will be lost.
present in some high-class cars, not only in the application engine ECU, ECU can find traces in many other places. For example, anti-lock braking system, four-wheel drive system, electronically controlled automatic transmission, active suspension systems, air bag system, the multi-adjustable electric seat so arranged the respective ECU. With the improvement of car electronic automation, ECU will be increasing, the line will become increasingly complex. To simplify the circuit and reduce costs, the vehicle information transfer between the plurality of ECU will use a technique called multiplexing communication network, the vehicle ECU to form a network system, i.e. CAN data bus.
4, ECU upgrade
by a computer program rewrite driving, to enhance the power, increased horsepower, torque or to reduce fuel consumption, vehicle performance optimization purposes. Because modern vehicles to adapt to the weather, the environment (such as high altitude, desert, cold and poor-quality gasoline and other harsh conditions) and the different requirements of various drivers, but it is also to ensure that this complex situation still able to pass a stringent exhaust emissions, fuel consumption standards, so in most cases, the program within the original ECU is the best compromise a number of conditions. In foreign countries, ECU tuning is a service provided when buying a car. Since the case where each vehicle is different factory, together with some of the techniques employed are car specific practical requirements may not meet adjusted trip computer (ECU) so that in addition to improve the output power of the engine, acceleration, and stability, but also that the car to better adapt to the relevant sections and the environment.
5, ECU composition
ECU by the throttle position sensor, intake air temperature sensor, air flow sensor, a water temperature sensor, speed sensor, Hall sensor, knocking sensor, an oxygen sensor is mainly composed of components