Truck engine and efi engine, which is of two types of engine is commonly used in engineering machinery.
They each have different working principle and characteristics.
In principle, the di engine way is to use mechanical linkage control injection time and injection volume, mainly through the high pressure oil pump pressurized diesel, and the mechanical atomizing diesel spray nozzle.
Straight engine, its characteristic is the machinery control injector fuel injection time and injection quantity, fuel injection pressure is small, atomization effect is poorer.
Efi engine is divided into monomer pump, injector type electronically controlled fuel injection system, as well as electronically controlled high pressure common rail type several forms.
As for our common diesel engines, mainly is for high pressure common rail technology.
High pressure common rail technology, it is formed by high pressure oil pump pressure after high pressure storage rail, through the computer ECU to control the fuel injector solenoid valve, according to all kinds of sensor signal control solenoid valve open, adjust the volume of injection time and injection to achieve, can even realize segmentation injection, making diesel reached the best burning effect.
Efi engine is controlled by computer injector fuel injection time and injection volume, injection pressure, atomization effect is obvious.
Di engine is controlled by the rotational speed, it is people control throttle opening knob and artificial selection dynamic mode switch to control the throttle opening, the overall structure is simple.
Efi engine by the controller to detect the following signals: the throttle opening Angle of rotation, dynamic mode switch, engine speed, rotating speed of pump pressure, the operating valve of pilot control valve, excavator working pattern, as well as the water temperature, oil temperature and so on.
Then, the computer ECU according to the driver's operation idea, according to the dynamic model and work in different ways, load and operating conditions to determine an optimal position of the throttle opening (
The optimal engine speed value)
At the same time, computer ECU can also control the throttle opening rate of change (
The throttle opening from the Angle of a transform to another Angle speed)
, let the engine can exert the best performance.
Di engine technology is mature, the product high residual value rate (
That the value of direct injection excavator use end)
The relative value.
Defect is due to the high speed of diesel engine, the fuel injection time is short, only a few seconds per thousand, and in all parts of the high pressure oil pipe in the process of injection pressure changes with the change of time and location, and due to the compressibility of diesel oil and diesel oil in the high pressure oil pipe pressure fluctuation change, makes the actual injection as prescribed by the state and fuel injection pump plunger oil law there is a big difference.
Sometimes, the pressure inside the tubing fluctuation will be after the main injection, makes the pressure inside the high-pressure tubing will rise again, will let the injector needle valve to open again, can appear the phenomenon of secondary injection.
We know that the secondary injection is not possible to fully burn, and then increased hydrocarbons and smoke emissions, thereby increasing the fuel consumption.
In addition, every time after the injection cycle, high pressure tubing within the residual pressure will change, it is easy to cause instability of jet.
According to the old driver, this the easiest way to produce when the engine at low speed, at the height of oil will not only uneven, and did not occur randomly injectors injection.