2JZduino is a digital signal processing unit designed for use with a forced induction system added to a Toyota 2JZ-GE 3.0L inline-6 engine. It performs ignition timing delay for cam and crank signals, simulated narrowband oxygen sensor output, and fuel injector scaling. The signal outputs are all programmable based on measured engine speed and an onboard manifold air pressure sensor.
A simple schematic of 2JZduino functionality is shown below…
Fuel Injection Scaling
When installing a forced induction system, it is common to change to higher flow-rate injectors and also a larger diameter intake tube. The fuel injection scaling feature allows the amount of fuel delivered to the engine to be increased by up to 20% to correct for any difference relative to the stock air/fuel ratio delivery.
Oxygen Sensor Signals
Oxygen sensors in the exhaust stream report the air/fuel ratio of the combustion chamber and is used by the IS300 ECU for closed-loop fuel control. The simulated narrowband output signal is generated from a wideband oxygen sensor signal and a programmable target air/fuel ratio based on engine speed and manifold air pressure.
Ignition Timing Delay
Cam and crank signal pulses are generated while the engine is turning. Ignition timing control allows these signals to be delayed based on engine speed and manifold air pressure. Timing delay can be retarded by 0-15 degrees in 0.1 degree increments.
Hardware/Firmware Design Features
- All input and output signals are interrupt driven using all 4 of the 16-bit timers onboard the ATMega 1280 chip of Arduino Mega.
- Fuel injectors are driven by high-speed/high-current logic-level MOSFETs.
- Firmware includes support for an LCD for data display.
- Uses onboard EEPROM for programmable data.
- 16MHz clock operation provides an interrupt service resolution better than 0.5 degrees at 7000 RPM.
Design and development details of these and other features will be posted to the 2JZduino category. Some preliminary photos of the 2JZduino shield for Arduino Mega and the LCD are shown below.