Application and electronic control system of elect

Application and electronic control system of electric control common rail diesel engine for construction machinery

the exhaust gas emitted by diesel engine has become the main source of pollution to the earth's environment; With the continuous improvement of emission regulations and fuel economy and power requirements, countries around the world have begun to look for and take effective technical measures to actively reduce and control the emission of pollutants with improved quality and efficiency; The common rail electronically controlled fuel injection technology of diesel engine is a relatively successful new technology to control pollution emissions

the high pressure common rail fuel injection system can flexibly adjust the injection timing, injection duration, injection pressure and injection law; First of all, in order to reduce the combustion noise of diesel engine, pre injection is required. In order to make the fuel burn fully and reduce emissions from the cylinder, it is necessary to improve the fuel atomization quality, improve the injection pressure, increase the number of injection holes, reduce the diameter of injection holes, and realize multiple injection; At the same time, the response characteristics of the fuel injection system are improved

electronic fuel injection technology makes the power output and load of diesel engine match more accurately. With the rapid development of construction machinery manufacturing technology, in order to improve the operation efficiency of construction machinery, the EFI common rail diesel engine is adopted, so that the construction machinery can automatically adjust the power output and power transmission within a certain range with the change of load, so that the power output and load of the diesel engine can be more accurately matched, and the operation efficiency of construction machinery can be brought into full play

electronic fuel injection technology expands the functions of fault diagnosis, contact and so on. With the automatic control system, it can be easily connected with the microcomputer, and it is easy to realize the function of diesel engine performance detection and fault diagnosis. The problems of diesel engine operation and the storage and transmission of detection data are also solved, which is convenient for scientific management and maintenance

basic knowledge of electronic common rail control:

electronic fuel injection technology can make diesel engines run with lower emissions, better fuel economy, power and low noise; High pressure common rail system is an ideal fuel injection system for diesel engines to meet the emission regulations of Europe II, Europe III and even Europe IV

the common rail control system can be divided into the following four aspects: sensor, engine ECU, actuator and diagnostic system

monitor the working condition of engine and pump; Provide engine control computer input signal

commonly used sensor signal input types and functions:

(1) accelerator pedal position sensor

reflects the engine load signal and idle speed confirmation, master control signal

(2) speed sensor, crankshaft position sensor

the main control signal and accelerator pedal position sensor jointly determine the fuel injection quantity and fuel injection advance angle 4 Reduce the influence of barrel temperature on color difference

(3) coolant temperature sensor

monitors the engine operating temperature and corrects the fuel injection quantity and timing

when the sensor fails, Hercules Aluminum Co., Ltd. has a total investment of 2.5 billion yuan and an annual output of 250000 tons of aluminum plate, strip and foil. When the project is fully put into production, the engine control computer ECM uses 90 degrees Celsius to calculate

Figure 3 engine water temperature sensor

(4) intake air temperature sensor

detects intake air temperature, corrects injection quantity and injection timing

when the sensor fails, ECM uses 90 ℃ to calculate

(5) intake pressure sensor

detects intake pressure, corrects injection quantity and injection timing

engine electronic control unit ecu

receives signals from the sensor and sends appropriate signals to the actuator to achieve the correct injection quantity, injection time and injection times required for the best operation of the engine

monitor the status and performance of each sensor, actuator and circuit for ECU to determine control strategy and external diagnosis. At the same time, the adaptive control is completed

receive the output signal of engine control unit ECU, and the injector injects foggy diesel into the cylinder

sensor signal classification, analysis and application:

resistance partial pressure sliding rheostat

is mainly used in accelerator pedal position sensor

on-off contact switch mode

is mainly used for accelerator pedal position sensor

positive and negative temperature coefficient resistance variable resistance type

is mainly used in engine temperature sensor and intake air temperature sensor

pulse magnetic induction type

is mainly used in engine speed sensor and crankshaft position sensor, which is characterized by weak low-speed signal

torque tooth wave hall type

is mainly used in engine speed sensor and crankshaft position sensor, and the signal is not affected by speed

film pressing resistance or voltage difference strain gauge

is mainly used in pressure sensors

maintenance methods:

with the development of electronically controlled fuel common rail technology and the application of common rail diesel engine, the traditional maintenance methods have been unable to carry out the maintenance of electronically controlled common rail diesel engine, and the maintenance field has undergone fundamental changes

the engine shall be repaired according to the company's exposure light, poor engine performance or no major changes

this is the most common and simplest fault in maintenance

(1) general method to detect whether the engine has mechanical failure

(2) the engine tester detects the engine fault code, and then detects the current fault code again after clearing the fault code

(3) according to the fault code prompted by the tester, detect the open circuit and short circuit of the sensor or actuator circuit

(4) use the multimeter or engine tester data flow function or actuator detection function to detect the sensor or actuator

(5) after maintenance, eliminate the current fault code