Daimlerchrysler Corporation

Chrysler Corporation

Eugenio DiValentin

Gregory L Ohl

Michael J Prucka

Timothy A Coatesworth

Denise M Kramer

Roger K Vick

Mark J Duty

Michael A Bonne

Zhong Li

A residual ratio factor characterizing the amount of residual exhaust gas left in a selected cylinder at the end of a piston intake stroke is determined from tabular and surface models based on previously gathered dynamometer data from a test vehicle at various engine speeds. The residual ratio factor is then used to calculate the mole fractions of air and residual exhaust gas in the selected cylinder, which, in turn, are used to determine mass airflow at an engine intake port at the end of the intake stroke. The mass airflow can then be used to derive further models for determining an engine operating parameter, such as fuel/air ratio, required for achieving at preselected vehicle operating condition.

Method for controlling an operating condition of a vehicle engine

A method for controlling airflow in an intake manifold of a multiple-displacement engine during an engine displacement mode transition includes determining, before a displacement mode transition, a post-transition mass air flow rate necessary to maintain a pre-transition engine torque output, as well as an airflow transient multiplier based on engine speed and an estimated post-transition manifold air pressure. After multiplying the requested mass air flow rate with the transient multiplier, the resulting compensated requested mass air flow rate is divided by a maximum mass air flow rate to obtain a requested percent airflow. The percent airflow is thereafter used with engine speed to determine a requested post-transition manifold air pressure-to-barometric pressure ratio, for example, using a lookup table; and the requested post-transition pressure ratio is used to determine a transient post-transition throttle position, to which an engine throttle will be moved upon initiating the displacement mode transition.

Airflow control for multiple-displacement engine during engine displacement transitions

Growing community of inventors

Brighton, MI, United States of America

Eugenio DiValentin