Kinsler_Handbook_#32 December 2017

Kinsler Fuel Injection, Inc, 1834 THUNDERBIRD TROY, MICHIGAN 48084 U.S.A. Phone (248) 362-1145 Fax (248) 362-1032 137 EFI INJECTORS PINTLE TYPE Controls fuel flow by moving a pintle in and out of the fuel orifice. The pintle also atomizes the fuel by dispersing the fuel in a cone shaped pattern. These spray patterns will generally vary from 15 to 30 degrees of included angle dependent upon the injector selected. Fuel atomization is very good with these injectors. THERE ARE THREE TYPES OF DESIGN FOR EFI INJECTORS - PINTLE, DISC, and BALL : THE BASICS OF AN EFI INJECTOR An EFI injector is a electronically controlled solenoid that controls fuel flow through an orifice. When the solenoid is activated, the orifice is exposed allowing fuel to flow. EFI injectors are avail- able with various flow capacities. The injectors are electronically pulsed, typically measured in milliseconds (thousandths of a second), to control the amount of fuel delivered to the engine. The percentage of time that the injector is pulsed is called the duty cycle. 100% duty cycle or Static Flow means the injector is open all the time. Static flows for injectors are specified at a certain pressure level. The test pressure rating may be in PSI, BAR, KPA, or KG/CM 2 . Manufactures rate their injectors at different pressures. For accurate comparison of flow rates, be sure you are comparing flows at the same pressure levels, (see Fuel Flow versus Fuel Pressure - Page #138). When properly sized for a specific application the injector will normally operate at 80-90% duty cycle. Injectors that are too large will not accurately deliver small amounts of fuel for good idle quality. Injectors that are too small may cause severe engine damage because of lean mixtures at large throttle openings and/or high engine RPM. DISC TYPE Controls fuel flow by lifting a disc off of its seat. The disc has as many as six holes around its circumference. When the injector is activated,the disc is raised and fuel flows through the holes and exits out the orifice. The disc in this injector may actually rotate while the injector is operating. The spray pattern of this type of injector will generally vary for 10 to 20 degrees. These narrower spray patterns can aid in targeting the fuel. Fuel atomization is typically not as fine as the pintle type injector. BALL TYPE Controls fuel flow by raising a ball off its seat. This allows fuel to flow through the seat orifice and then out through a fixed director plate with several holes. The director plate serves to direct the fuel spray pattern. This type of injector has a 10 to 15 degree included angle spray pattern. The fuel atomization of this type of injector is similar to the disc type injector. Disc and ball type injectors by design are less susceptible to clogging. We have not experienced any clogging problems provided that the fuel is filtered. (See Kinsler Fuel Filters on Pages #162-166). 1 - Filter 2 - Magnetic winding 3 - Solenoid 4 - O-ring 5 - Needle valve pintle 6 - Spray tip 1 - Filter 2 - Core 3 - Body 4 - Shim 5 - Valve seat 6 - Nozzle 7 - Calibration slide 8 - Spring 9 - Coil assembly 10 - Spacer 11 - Disc SIEMENS DEKA © 2017 1 - Filter 2 - Guide ring 3 - Spacer 4 - Core spring 5 - Seat spring 6 - Seat 7 - Pole piece 8 - Stop 9 - Solenoid coil 10 - Solenoid body 11 - Core ring 12 - Core 13 - Spray tip housing 14 - Director 15 - Spray tip