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 119 TURBOCHARGED CONSTANT FLOW INJECTION SYSTEM TYPICAL VALVES AND FUNCTIONS Main bypass : Set for nominal 2-3 PSI and has changeable metering jet. Controls fuel pressure for starting and low speed off-boost opera- tion. The jet in this valve controls fuel rates at part throttle and off boost conditions. (Also see Economizer valve) Secondary bypass : this valve is typically set for 8-25 PSI blow off (depending on exact application). The function of this bypass is to control fuel pressure at part throttle operation where high engine RPM is experienced. This valve is mechanically shut off at about 50% of throttle opening. (See INDEXING A BARREL VALVE on Page #108) Air valve : commonly called the “A” valve. This valve holds an orifice which reduces the amount of boost signal that is sensed at the boost sensor. The larger the jet in the air valve, the more boost the sensor will see, therefore making the injection unit go richer. This valve aids in controlling fuel under boost conditions ONLY !!! Boost sensor valve : this valve controls fuel enrichment on a boosted engine by restricting the fuel flow back to the fuel tank. A piloted valve suspended on a diaphragm slides into the return port seat. When boost signal is applied to the dry side of the diaphragm, the air pressure pushes the valve toward the seat and restricting the return flow which richens the engine. When no boost signal exists on the diaphragm, the return flow pushes the valve and diaphragm away from the seat, opening sufficient area for fuel return. Economizer valve : this valve is used to restrict the amount of fuel flow and pressure to the barrel valve and nozzles on injection systems with a single set of nozzles that are sized for high flow conditions. Nozzles that are sized for high flow conditions (boosted engines), are too rich for part throttle operation. The system would be very difficult to tune as a small change in pressure will cause a significant flow change. Adjustment of economizer valve; remove shims from this valve to increase fuel flow at part throttle, especially as boost is just starting to come on. #5 valve : (not shown in plumbing schematic) is used to bypass fuel directly into the fuel tank to decrease the return volume passing through the boost sensor valve. When the valve diverts fuel into the tank, the boost sen- sor enrichment rate will be reduced. Changing this valve’s spring rate will mostly effect the point of opening while changing the restrictor jet will effect the tapering of enrichment from the boost sensor. The larger the bypass jet the slower the enrichment will be, (more gradual enrichment). This valve is similar to a high speed bypass on a normally aspirated engine. The signal pressures in this chart are relative due to the flow variations of the orifice in the boost sensor valve body. Unlike positive-displacement blowers (GMC roots blowers), the boost a turbocharged engine is not directly proportional to engine speed. Since the boost level is not directly tied to RPM and throttle position, a conventional mechanical fuel injection system, with a barrel valve and mechanical pump, cannot respond correctly to the engine’s fuel requirements. The system requires two stages of fuel delivery. One stage fuels the engine under the naturally aspirated conditions while the second stage takes over when the engine goes into boost. The second stage is activated via the use of an air valve and a boost sensor valve (See schematic below). © 2017 “A” Valve Signal to Jet Sensor (PSI) .034” 18.50 .036” 20.00 .038” 21.50 .040” 22.75 .042” 23.50 .044” 24.25 .046” 25.50 .048” 25.75 .050” 26.25 .054” 27.25 .058” 27.75 .062” 28.25 .066” 28.75 .070” 29.00 Signal pressure at 30 PSI boost with various KINSLER ‘A’ -valve jets. Boost sensor valve Duane Schroeder’s triple turbocharged alcohol John Deere ® super stock pulling tractor