Abstract: Methods and systems are provided for estimation of a road roughness index (RRI) and adjusting vehicle operation based on the metric. In one example, a method may include estimating the RRI as a function of a pitch energy and a roll energy of the vehicle travelling on the road. In response to the RRI being higher than a threshold, engine operation such as EGR flow rate may be adjusted.

Abstract: Methods and systems are provided for estimation of a road roughness index (RRI) and adjusting vehicle operation based on the metric. In one example, a method may include estimating the RRI as a function of a pitch energy and a roll energy of the vehicle travelling on the road. In response to the RRI being higher than a threshold, engine operation such as EGR flow rate may be adjusted.

Abstract: Systems and methods for controlling operation of deactivated engine cylinders are presented. In one example, intake valve timing of deactivated engine cylinders is advanced to reduce amplitudes of intake pressure pulsations while exhaust valves of the deactivated engine cylinders are held closed. Further, intake valve timing of deactivated cylinders may be advanced responsive to output of an intake manifold pressure sensor.

Abstract: Systems and methods for controlling operation of deactivated engine cylinders are presented. In one example, intake valve timing of deactivated engine cylinders is advanced to reduce amplitudes of intake pressure pulsations while exhaust valves of the deactivated engine cylinders are held closed. Further, intake valve timing of deactivated cylinders may be advanced responsive to output of an intake manifold pressure sensor.

Abstract: Systems and methods for operating an engine in a variety of different cylinder operating modes are presented. In one example, an actual total number of available cylinder modes is increased in response to a vehicle's suspension setting and road roughness. By increasing the available cylinder modes, the engine may be operated in a higher number of modes where one or more engine cylinders may be deactivated to conserve fuel. The number of cylinder modes is increased during conditions where vehicle occupants may be less likely to object to operating the engine with fewer active cylinders.

Abstract: Systems and methods for operating an engine in a variety of different cylinder operating modes are presented. In one example, an actual total number of available cylinder modes is increased in response to a vehicle's suspension setting and road roughness. By increasing the available cylinder modes, the engine may be operated in a higher number of modes where one or more engine cylinders may be deactivated to conserve fuel. The number of cylinder modes is increased during conditions where vehicle occupants may be less likely to object to operating the engine with fewer active cylinders.