Enhancements to Engine Operation

WARNING: This page is about a different car, the 2012 GMC Yukon, 2012 Chevrolet Tahoe, and 2012 Cadillac Escalade. However, it is still accessible from the selected car via links, so may be relevant.

While not unique to the Two-Mode hybrid vehicle, the following modes of operation benefit from expanded operational ranges. Expanded operational range is possible because the drive motor generators can be utilized to smooth driveline disturbances that would be objectionable without the intervention of the drive motor generator.

Deceleration Mode

When the driver releases the accelerator pedal, air flow into the engine is reduced. The ECM monitors the corresponding changes in the TP, the MAP, and the MAF. The ECM shuts OFF fuel completely if the deceleration is very rapid, or for long periods, such as long, closed-throttle coast-down. The fuel shuts OFF in order to prevent damage to the catalytic converters. This mode is activated more quickly and for a longer duration in the Two-Mode hybrid vehicle.

Cylinder Deactivation (Active Fuel Management)

To provide maximum fuel economy under light load driving conditions, the engine control module (ECM) will command the cylinder deactivation system ON to deactivate engine cylinders 1 and 7 on the left bank, and cylinders 4 and 6 on the right bank, switching to a V4 mode. The engine will operate on 8 cylinders, or V8 mode, during engine starting, engine idling, and medium to heavy throttle applications. This mode is activated more quickly and for a longer duration in the Two-Mode hybrid vehicle.