Powertrain Management: Description and Operation

PURPOSE
The Powertrain Management and control system electronically regulate the air / fuel mixture, idle speed, ignition timing / advance and other systems to achieve optimum engine and emissions performance.

INFORMATION STRUCTURE
Information regarding Powertrain Management is divided into the following four major topics:

Computers and Control Systems
Addresses the on-board computer system and components as related to engine management. This would include:
- On-board diagnostics system which monitors actuator and sensor input and will store a code in the event that a failure of a controlled system is detected.
- Injector duration control based on inputs from various sensors the Engine Control Module will vary the injector on-time to control air / fuel mixture to maintain optimum performance and driveability.
- Idle speed control is monitored and adjusted by the Engine Control Module to maintain idle quality under various engine conditions.
- Ignition spark is controlled by the Engine Control Module to provide the correct timing advance under various engine conditions to maintain optimum performance and emissions.
- The Engine Control Module also works in conjunction with the Emissions Systems to help maintain optimum emissions levels.

Emission Control Devices
Addresses emission related systems and components.
- The Exhaust Gas Recirculation system is utilized to reduce combustion chamber temperatures thereby reducing NOx emissions. This system is controlled and monitored by the Engine Control Module.
- The Evaporative Emission Control system is used to reduce HC emissions by burning fuel vapors in the combustion process. This system is controlled by the Engine Control Module.
- The Positive Crankcase Ventilation system is a mechanical system which is not monitored by the Engine Control Module and is used to reduce HC emissions
- A Three-way Catalytic Convertor is used to reduce HC, CO, and NOx emissions. The Three-way Catalytic Convertor is dependant on the Fuel Injection System to maintain the correct air / fuel ratio required to make the Three-way Catalytic Convertor work properly.

Fuel Supply and Induction Systems
Focuses on systems and components related to fuel and intake air delivery.
- The Fuel Pump is employed to supply fuel from the Fuel Tank to the injectors at a controlled high pressure. The power to the Fuel Pump is controlled by the Engine Control Module based on various signals from engine sensors.

Ignition System
Focuses on primary and secondary ignition systems and components.
- The ignition components work in conjunction with the Engine Control Module and supplies secondary voltage to the Spark Plugs. The timing of this spark (Spark Control) is controlled by the Engine Control Module based on various signals from engine sensors.