Characteristics and differences of EGR, high pressure common rail, single pump engine
When purchasing a vehicle, many customers were confused about the structure of the National Engine, namely EFI, EGR, and single pump. Here, Cheng Li, a special car manufacturer, introduces you to the features and differences of these several engines. Features of EGR engine; fuel injection system is similar to the structure of the original State II mechanical injection pump, easy maintenance and maintenance, operating costs are greatly reduced, oil adaptability is good, the current national general-purpose diesel can be applied, suitable for national conditions, downsizing maintenance and repair Cost, user cost reduction. The fault diagnosis system is complete in function and easy to operate. It can realize the accurate judgment of the electronic control system faults, simplify the maintenance process, and the after-sales service is convenient: more than 95% of the EGR engine can be exchanged with the national II machine, maintenance and Easy maintenance, reduced maintenance waiting time, and reduced maintenance costs. EGR technology, which is an exhaust gas recirculation technology, combines a portion of the exhaust gas with an intake pipe and fresh air and then enters the cylinder for combustion to increase the heat capacity of the air-fuel mixture, reduce the maximum temperature during combustion, and suppress NOx generation. To achieve the lowest NOx in the exhaust gas. In order to achieve the three national standards. EFI monomer pump engine features: Most European Euro IV Euro IV commercial vehicles use electronically controlled monomer pump systems, electronically controlled monomer pump technology plus mechanical injectors to achieve Euro III emission standards; upgrades from Europe III To Euro IV, by replacing the electronically controlled fuel injectors, there is no need to make large-scale modifications to the structure of the engine; the engine structure of the original mechanical fuel injection system is changed little, and the same components such as the same body and cylinder head can be shared; after-sales maintenance Convenience and low parts replacement cost; high injection pressure: can meet the high-pressure injection required by Euro III and Euro IV emissions (the latest single pump injection pressure has reached 2500bar), which greatly improves fuel economy and improves in-cylinder Degree of purification; fuel injection law is firstly reduced and then urgent, meets the requirements of ideal heat release law, which is beneficial to reducing emission and combustion noise; strong oil supply capability: independent control of each cylinder can be performed. Particularly suitable for heavy duty diesel engines;  Characteristics of the EFI high-pressure common-rail engine: For light vehicles, the system components are mature and have long-term evaluation and verification, and the medium-sized engines are relatively mature; however, the service life of heavy-duty diesel engines has not been verified. The structure is simple and easy to install. The common rail oil pressure is independent of the engine speed control, the vehicle control function is strong, and it can meet the requirements of light vehicles; the pre-spray technology can reduce the idle noise; the initial injection rate of the common rail system is too high and does not meet the needs of the diesel engine for the first time. The emergency law is not conducive to emission control; a common rail injection pressure is 1350~1450bar, and the second generation is 1600bar. Overall, it is lower than the single pump and pump nozzle, so there is a disadvantage in fuel consumption; multiple injections can be realized. At present, the best common rail system can perform 6 injections; the common rail system has good flexibility, but it will inevitably bring difficulties in matching work. The level of time and technicians determines that certain stages of use in China are too flexible  At present, there are mainly three kinds of engines that can meet the three national emission standards. One is an electronically controlled high pressure common rail engine, one is an electronically controlled single pump engine, and the other is an electronically controlled EGR engine, single pump and high pressure. The most critical fuel injection system technology for common-rail engines is currently monopolized by a few foreign companies such as Bosch, Denso, and Delphi. However, these three international suppliers could not meet the needs of domestic diesel engine companies in the short term. Although domestic oil pump plants are developing autonomous electronically controlled injection systems, they are still technically immature. The threshold of EGR technology is not high and can be accompanied by the country's third emission level, and the cost is lower by tens of thousands. This is also the current domestic development of EGR. s reason. Cheng Li special car: Home Brewing,Conical Fermenter,Beer Fermenter Flowtam Light Industry Machinery Co., Ltd. , http://www.flowtamtank.com
In medium-heavy duty, system components are more mature than common rail systems due to differences in internal structural characteristics. Compared to the common rail system, the single pump system has relatively low requirements on fuel quality, sensitivity to moisture is much better than that of the common rail system, there is no potential safety hazard caused by continuous injection of high pressure sources, and the discharge stability is good. The system components are maturer than the common rail system and have long service life; the maintenance cost is low: single-cylinder components can be replaced, the cost of the mechanical injector is lower than that of the electronically controlled injector, and the cylinder balance control strategy provides good cylinders Consistency control, single-pump self-tuning strategy to ensure the production of consistency control, electronic control system self-learning, self-diagnosis strategy to ensure consistency in the control of the life of the performance. The electronic unit pump system is a modular, time-controlled single-cylinder high-pressure pump system. The injection start point and fuel injection quantity are determined by the closing time and the closing time of the solenoid valve respectively, and can reach the injection pressure of 2000 bar. The electronically controlled monomer pump system is fully equipped with the technical capabilities to meet current and future emission limits and maintain low fuel consumption.
The system does not necessarily achieve the desired results; multiple injections, particularly after-spray capability, make the common rail system particularly convenient to work with after-treatment systems and have the potential to achieve Euro IV and Euro V emission regulations; fuel oil (water, ash impurities) ) Poor adaptability, high requirements on user's use conditions, especially complex control system and control strategy. It brings challenges to vehicle manufacturers, users, and after-sales maintenance. Parts replacement costs are high, especially electronically controlled injectors and electronic controls. Fuel injection pump; electronically controlled high pressure common rail technology refers to a technique in which the injection pressure generation and injection process are separated from each other in a closed loop system consisting of a high pressure oil pump, a common rail tube, a pressure sensor, and an ECU. The high pressure fuel pump uses high pressure fuel. It is transported to the common rail, and the pressure in the common rail can be closed-loop controlled. The pressure can be adjusted independently. At present, 1800 bar injection pressure can be achieved.