According to the shape of the head, the automatic injection machine for toys is divided into hole type, pin type and throttle type. Injectors with less than 4 holes are used in semi-open combustion chambers (see diesel engines); injectors with more holes are mostly used in open combustion chambers. Each hole of this fuel injector can spray oil jets with a small cone angle and a long range.

The number of holes, diameter and thickness of the hole wall have an impact on the spray characteristics, depending on the diesel engine model. Axle-pin injectors are used in separated combustion chambers such as swirl chambers and pre-combustion chambers and compound combustion chambers. The shaft needle of the needle valve head passes through the nozzle hole to form an annular spray passage, which can make the sprayed oil mist appear in a hollow cone shape. The throttling type is similar to the shaft-needle type, except that the needle valve rises by changing the shape of the shaft-needle to form throttling, thereby changing the fuel injection pattern and making the diesel engine work softly.

Toy automatic fuel injection machine processing timing and fuel injection processing rate:

At the same speed, the timing of fuel injection processing affects the effective length of the drain channel, and therefore, the fuel injection processing pressure and fuel injection processing rate characteristics of the electronic control system. When the plunger group is at 650r/min, the nozzle end pressure and the fuel injection processing rate vary with the timing of the fuel injection processing (T represents the timing angle of the fuel injection processing, the value of T increases, and the fuel injection processing is ahead of the glue nameplate).

The fuel injection processing timing is advanced, the effective length of the discharge channel is lengthened, the initial low fuel injection processing rate section is widened, and the initial fuel injection processing rate increases slowly, and a shoe-shaped fuel injection processing rate form can be formed during the entire fuel injection processing period. With the delay of the fuel injection processing timing, the width of the initial fuel injection processing rate section gradually decreases, while the initial fuel injection processing rate amplitude gradually increases. After the fuel injection processing timing is further pushed, when the control valve is closed, the discharge channel has all risen above the oil inlet hole, which can not play the role of discharge control. At this time, the fuel injection processing rate characteristics are determined by the fuel supply characteristics of the oil pump.