Digital Ignition

1
Digital Ignition Electronic Fuel Injection
by Richard Bohuslav Kosik Supervised by Dr Geoff
Walker

• Hardware Design Topology
• The universal closed loop hardware design has
  fully adjustable current limiting for both
  ignition drive and injection drive. The injection
  drive was specifically tailored to high
  performance injector solenoids with its two break
  point current limit design but still with the
  option of using conventional injector solenoids.
• MOSFET Technology
• IGBT Technology

Introduction The increasing demand for economy
and performance combined with more stringent
emissions and legislative requirements has lead
to the high level of complexity in engine control
modules. Two underlining factors that determine
engine performance and economy are ignition
timing and fuel induction. Previous mechanical
methods for ignition timing advance and
carburetted fuel induction have proven
inefficient and unfriendly to the environment,
this has called upon the need for precise
metering of fuel and split-second ignition
timing.
Fig 5. Ignition Injection Driver

• Why Digital Ignition?
• Electronic Ignition Systems (EIS) can vary form
  the simplest transistor-assisted and capacitive
  discharge systems to the most complex
  microprocessor controlled digitally mapped
  systems.
• Digital ignition map
• Fixed spark energy throughout r.p.m. range
• Functional with other systems, ie. traction
  control
• Higher reliability

Fig 1. Ignition block diagram
Fig 2. Injection block diagram
Simulation Results The entire design was
simulated in OrCAD PSPICE, with the following
results.
Fig 6. Power Electronics

• Why Electronic Fuel Injection?
• Electronic Fuel Injection (EFI) systems can
  compensate for fluctuations of air density by
  altering the air/fuel ratio. Thus a
  stoichiometric ratio can be kept constant
  regardless of climatic changes.
• Increase in fuel economy
• Lower exhaust emissions
• Precise fuel metering
• Better engine performance

Fig 4. Injector Current
Fig 3. Ignition Voltage
Conclusion The universal digital ignition and
electronic fuel injection driver successfully
operates as specified.
Fig 7. Control Electronics