#ADAPTRONIC PIEZO INJECTOR DRIVERS#
#ADAPTRONIC PIEZO INJECTOR DRIVER#

A fault will be stored if the injector adaptation exceeds a calibratable minimum or maximum value. The values of the separate map are renewed every 497 miles. A small proportion of the short term fuel deviation is used for diagnostic injector aging and is stored as an injector adaptation value in a separate map. The self-diagnosis system as it pertains to fuel system monitoring, and particularly fuel injectors, can be broken down into:ĭiagnosis of injector aging is simply a way of monitoring injector adaptation. Previous articles have looked in depth at the GDI system as a whole. We won’t spend much time on the theory and operation of the GDI system and how it works other than a bit of a refresher in regard to how the monitoring system affects the injectors. Voltage returns to approximately 13.5 V and the holding current drops to around 3 to 4 amps for the remainder of the injection event.

#ADAPTRONIC PIEZO INJECTOR DRIVER#

The driver will boost current to around 10 amps for a few hundred microseconds.

The driver will provide a boost voltage of up to 200 volts.

#ADAPTRONIC PIEZO INJECTOR DRIVERS#

The drivers in the DME control both voltage and current.Some basics of piezo or high voltage injectors: Piezo injectors are quieter and more precise than solenoid units, a huge benefit when microseconds count! The piezo stack is energized by the fuel control unit and the injection event takes place. But the unique property of a piezo crystal, as mentioned before, is that it changes shape when exposed to electric current.įirst high pressure fuel enters the injector all the pressure throughout the injector is equal at this point. In a piezo injector, the electronic engine management system sends an electrical signal to the valve, much like the solenoid operated valve. Since this movement is a downward motion, a lever and spring setup inside the injector allows the pintle to open and close. The actual movement is microscopic, but enough to make the piezo element act as the valve. This translates into precise fuel metering and allows for multiple injector events to occur each combustion cycle.Ī piezo element only expands a miniscule amount, so hundreds of slices are stacked on top of each other so that the net movement is only about 0.004 inch. Modern BMW piezo injectorsĪlthough manufacturers such as Bosch, Siemens, and Delphi are all working on a solenoid based injector design that will perform as well as the piezo type, we will focus on the latter as these injectors are what you will encounter most often.Īccording to Bosch, which introduced piezo injectors to the industry, a piezo actuator acts up to five times faster than a standard injector solenoid and the motion is frictionless. But before we get into that, let’s delve into what makes the modern BMW injector work. BMW made the switch to direct injection for good reason - namely, improved fuel efficiency, lower emissions, better performance, and cooler cylinder temperatures. In 2007 BMW introduced the N54 engine featuring direct injection and turbocharging on the 335i model.īMW’s current lineup features almost all turbocharged and direct injected engines. However they did not implement DI in automotive applications until the mid 2000s. Direct injection is not all that new.īMW used direct injection in airplane engines in the 1930s. Port injection has been phased out and you will mostly see the direct type injectors in the field. When we discuss BMW fuel injectors we will focus primarily on the direct injection type or GDI. Understanding new technology is the key to successful repairs.

Adaptronic piezo injector