Structure Characteristics of VE Dispenser and Implementation of Electric Controlling

The structure characteristics of the VE type dispensing pump and the implementation of its electronic control system were too hiring. The Jiang Bing (Department of Mechanical and Electrical Engineering, Taiyuan University, Taiyuan 030009, Shanxi, China), the oil was uniform, the idle speed was fixed, and the oil regulation was convenient. The advantages, and its excellent performance is determined by its unique design. In order to meet the increasingly stringent emission standards of diesel engines, and at the same time ensure its good dynamics and economy, the use of electronically controlled fuel injection systems is one of the most effective methods. There are two possible solutions for implementing electronic control on a distribution pump. The control accuracy and control functions are difficult to achieve with a mechanical oil pump.

Key words: distribution; structural characteristics; electronic control With the increasingly stringent economic indicators and emission targets for vehicle engines in various countries, diesel engines have replaced petrol engines in many areas due to their outstanding advantages of low fuel consumption and good emissions. Especially for cars and light vehicles that are closely related to people's lives, the use of diesel engines as power devices is even more prominent. Accordingly, higher performance is required for diesel engines. For example, diesel engines for light vehicles should have higher performance. , Comfortable running performance, good startability and adaptability to the environment. As a heart component, the high-pressure fuel injection pump is a key component to improve the performance of diesel engines. The pressure injection pump has undergone the development of an electronically controlled injection system developed in recent years, ranging from in-line pumping, pumping and pump injector systems. However, it is currently the most widely used and fastest-developing dispensing pump in China. Many domestic diesel engines have been equipped with distribution pumps, such as the SOFIM launch of the Nanjing Automobile Manufacturing Plant, the Isuzu 4JBI diesel engine of the Beijing Internal Combustion Engine Plant, and the Shanghai Santana Diesel Engine. These diesel engines are equipped with the VE type dispensing pump with excellent performance. This article analyzes the structural characteristics, technical level and electronic control technology of the common VE type distribution pump on light vehicles. I hope to be helpful to the use and maintenance personnel of light diesel vehicles.

As we all know, the inline pump is characterized by a set of drive, pump oil and adjustment elements corresponding to an engine cylinder. Then a group of identical elements is combined by a pump body, and various components are added externally to increase the number of components. Control functions, such as governors, auto-advancers, smoke limiters, etc. Compared with the later developed distribution pumps, in-line pumps have the disadvantages of large volume, large number of precision coupling parts, large strokes, and complex adjustment and maintenance. Dispense pump is developed for the shortcomings of in-line pumps. Its structural features are: First, only one pair of precision couplings is used to pump oil, and then high pressure oil is distributed to each cylinder in turn. This structure greatly reduces the volume and weight of the dispensing pump. In particular, the miniaturization of the distribution pump governor shortens the size in the longitudinal direction, which is critical for a compact, small-diameter, multi-cylinder diesel engine. Secondly, the oil pump, advancer, and governor are all centralized in one pump body by the sub-pump to facilitate the overall layout of the diesel engine. In addition, the distribution pump no longer repeats many parts several times as many as the number of cylinders, which results in a reduction in the total number of parts, and in particular a reduction in the number of precision coupling parts, which reduces costs. Due to the small adjustment force of the adjustment mechanism, the distribution pump is easier to implement electronic control than an in-line pump.

In terms of service and maintenance, due to the uniformity of the injection quantity of each cylinder and the corresponding advance angle, it is ensured by the manufacturing process and no adjustment is required.

-), Female, Lecturer in the Department of Mechanical and Electrical Engineering at Taiyuan University. The outstanding advantages of the Master's Research *52* Dispense Pump make it a dominant position in small high-speed diesel engines.

Among the distribution pumps, the VE type dispensing pump occupies the absolute advantages of the small-scale high-speed vehicle diesel engine matching injection pump market with its unique structure and excellent performance, and represents the development direction of the mechanical distribution pump for today's automotive diesel engines.

The new distribution pump. Its main features are: an adjustment sleeve is added on the plunger, and its axial displacement is used to control the plunger to open the oil hole sooner or later to perform the fuel metering control. The adjusting sleeve is controlled by a micro speed governor which accelerates the gear. Available accessories include positive and negative correction of starter enriched oil, advance mechanism, starting electromagnetic machine, booster type altitude compensator, temperature starter and idle speed device, etc., and become a distribution pump that can add additional devices. The diameter of the VE pump plunger is small, and the rotation plus reciprocating motion should not be stuck. The four rollers share the hydraulic pressure of one plunger and the contact stress is small. Can install more accessories, improve performance, easy to measure the broken fuel electronic control. However, the VE pump plunger has many slot holes and high working frequency, which is prone to wear, and the cleanliness of the diesel oil is required.

Compared with in-line pump, VE pump has the advantages of high rotation speed, uniform oil supply, stable idle speed and convenient oil adjustment. Compared with other types of distribution pumps, the VE pump's maximum oil supply, the most squeaky pump end pressure, and the maximum speed are all outstanding.

The use of electronic control technology is one of the important directions for the development of diesel engines. Among them, the electronic control of the fuel injection system is the most critical. Electronically controlled fuel injection system has two main advantages: First, it has high control precision, it can accurately control fuel injection quantity, fuel injection timing and other control quantities to ensure good performance of diesel engine; second, multi-parameter control, In addition to controlling the two basic parameters of fuel injection quantity and fuel injection timing, the electronically controlled fuel injection system can also control parameters such as fuel injection rate, injection pressure, and fuel atomization characteristics, which is difficult for a distribution pump. of. First of all, because the control components of the dispensing pump are mostly pneumatically, hydraulically, or mechanically driven, its control characteristics are simple and it is difficult to achieve high-precision control. Secondly, in order to satisfy the multi-parameter control, the distribution pump is required to add more accessories, which tends to complicate the structure of the distribution pump and reduce the reliability of the distribution pump control. Judging from the control method, another significant feature of diesel electronically controlled fuel injection systems is the diversification of control methods, which is determined by the diversification of mechanical fuel injection pumps and the complexity of implementing electronically controlled actuators. At present, diesel engine electronically controlled fuel injection system can be divided into two major categories of position control method and time control method according to its control method. The position control method is to change the position of the rack and slide sleeve from original mechanical governor control to microcomputer control on the basis of retaining the original fuel injection system. The feature is that the microcomputer indirectly controls the fuel injection amount by controlling the position of the slide sleeve. And fuel injection timing. The time control method eliminates the conventional fuel quantity of the fuel control rack, the sliding sleeve, the advancer, etc. of the original fuel pump or the mechanical adjustment mechanism of the timing, and even completely abandons the existing fuel injection system and redesigns the electronic control according to the electric control requirements. Accumulator system and electronically controlled pump nozzle system. Its characteristic is that the microcomputer directly controls the fuel injection quantity and the injection timing through the solenoid valve. From the control effect, the time control method is superior to the position control method in terms of its high accuracy and good responsiveness. However, the position control method has little modification to the original machine, and the structure is simple and easy to arrange. Among them, dispensing pumps are easier to implement than electronic pumps. Due to the different structure and principle of the various distribution pumps, the implementation mechanism and the structure of the oil pump during the implementation of electronic control vary. Take VE Li, for example, there are two ways to realize electronic control on the VE pump developed at home and abroad: position-controlled electronic control pump and time-controlled electronic control pump. The control parameters are mainly injection quantity and injection advance angle.

1 position control type electric control VI pump W M into the dispersion This system is a position control type electronic control system implemented on the VE dispensing pump.

Its structural features are: the use of a linear electromagnet instead of the original mechanical governor to control the position of the oil sliding sleeve to achieve the control of the fuel injection quantity; the timing hydraulic solenoid valve is used to control the original hydraulic pressure advancer piston to achieve the fuel injection Advance control.

The control principle is: In the E-CU of various operating conditions and atmospheric parameters of the diesel engine collected by the sensor, the ECU rooted engine speed and the accelerator pedal position signal are theoretically injected in the MAP map of fuel injection volume. The target value of the fuel quantity is corrected with the environmental parameters, and the oil spill ring (sleeve) position sensor is used as a feedback signal to issue a control command to the actuator (linear solenoid valve) to achieve closed-loop control of the fuel injection amount. Similarly, for the control of the injection advance angle, the ECU obtains the target value of the theoretical injection advance angle on the map of the injection advance angle MAP according to the engine speed and the accelerator pedal position signal, and corrects the environmental parameters to position the advancer piston position. The sensor acts as a feedback signal and issues control instructions to the actuator (timing control solenoid valve) for closed-loop control.

System. It is a time-controlled electronic control system on a VE dispensing pump.

Its structural characteristics and control principle are: not only canceled the mechanical governor on the original VE pump, but also canceled the oil control slide sleeve, directly by the electromagnetic spill control valve to control the amount of fuel injection.

The injection timing control is also controlled by the timing control solenoid valve, but the advancement piston position sensor is cancelled, and the phase difference between the crankshaft position signal provided by the crank angle sensor and the toothless segment signal provided by the pump angle sensor is used as the feedback signal. , control the injection in advance.

Tests show that the use of electronic control system has the advantages of rapid response, high control accuracy, and flexibility and adaptability of control strategies. This will improve the power and economic performance of the diesel engine and reduce emissions.

In order to meet the increasingly stringent emission regulations, the improvement of the performance of the fuel injection pump for vehicle diesel engines is the main task at present. The VE type distribution pump, with its excellent performance, has become the main accessory product of the small-speed idle diesel engine, but it also exists. Its mechanical structure limitations. Implementing and improving electronic control on existing distribution pumps is the main direction of development in the future.

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