System Operation - Smart Charging System With Smart Alternator

Most current vehicles utilize the Smart Charging control strategy. This strategy helps to improve vehicle performance, reduce CO2 emissions and increase fuel efficiency. The control strategy takes into account battery state of charge and electrical loads on the battery, as well as engine load. Vehicles that utilize the Smart Charging control strategy are equipped with an Intelligent Battery Sensor (IBS). The IBS is an important component of the Smart Charging control strategy.

• Idle and acceleration:  Charging is typically suspended during idle and acceleration conditions. Due to this strategy it can be common for the alternator output to be equal to, or close to typical battery voltage at idle and during engine acceleration.
• Steady state speeds:  During steady state speeds the charge rate is typically low, just enough to maintain battery voltage.
• Deceleration (regenerative braking):  The charge rate is typically very high during deceleration.

The Smart Charging strategy can be used with any combination of the following vehicle configurations:

• Single Battery System
• Dual Battery System
• Electronic Voltage Regulation (EVR) Charging systems which use a standard alternator directly controlled by the PCM
• Charging systems using a smart alternator communicating with the PCM via LIN Bus

On vehicles equipped with a smart alternator, the PCM sends the voltage set point and ramp time commands to the alternator via a LIN bus communication circuit. The alternator controls the charging rate based on these commands.