Drivbiwire

Digital pressure sensing is used to read and and record injector data. The Pressure sensor is certified under ASME B40.7-2005 standards which permits accuracy to +/- 0.5% and a pressure range expanded to over 600 bar! Also due to the high speed cycling of the nozzles the new digital calibration equipment was selected due to its ability to read ALL pressure cycles that occur within a 10 milisecond window! To insure the highest level of accuracy the pressure resolution will be reduced to .068bar meaning extremely accurate pressure readings during all injector opening phases that no analog pressure gauge can display.

 

 

 

 

Unlike older "IDI" or "Pintle" style injectors, two-stage injectors precisely meter and inject fuel at different intervals of every combustion stroke in order to control the pressure rise in the cylinder. The resulting softer rise in pressure greatly reduces the "Diesel Knock" formerly associated with diesel engines. This however results in an injector that cannot be set thru conventional methodology. Two stage injectors require multiple steps to insure both injection events occur within a very narrow window of pressure to insure that the fuel metering is not effected to maximize the ECU's control of the engines combustion and power output. Each injection event in normal operation can be as rapid as 1.5 milliseconds in duration while tightly controlling the amount of fuel injected to minimize engine emissions output. 

 

  

Each pressure is set at a predetermined value based on the ECU fuel mapping's expectation of injector performance. The pressures of each stage although independant have a reliance on each other to achieve the specified pressure that respective stage should begin to open at. Manipulation of one pressure without adjustment to the other will cause an erronious pressure change on the other. Anytime one stage is changed the other too must be adjusted and set accordingly.

 

 

Injectors have a certain expectation of durability in a specific application. The primary factor that determines the life of an injector nozzle is the quality of the fuel filtration. peak pressures at the nozzle holes can exceed 2000 bar, any amount of suspended matter can cause the fuel to act like a cutting jet rapidly eroding the nozzles precision machined hole geometry. It is accepted that no matter how good the filtration is, it is impossible to completely eliminate all particles from the fuel. So, even with ideal conditions some erosion of the nozzle is expected and will occur thus the reason nozzle fuel spray should be evaluated at regular intervals to reduce the likleyhood of damage to the pistons combustion bowl and cylinders.