Daimlerchrysler Corporation

Chrysler Corporation

Michael J Prucka

Gregory L Ohl

Mark J Duty

Michael A Bonne

James W Yip

Daniel B Diebel

Eugenio DiValentin

Timothy A Coatesworth

Brian E Beechie

Marc H Sullivan

Roger K Vick

Denise M Kramer

Gregory M Pannone

Alan G Falkowski

Yi Cheng

Kerry D Franks

Zhong Li

Mark McElwee

Paul R Arlauskas

John S Mitchell

Michael A Boone

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

Prior to transitioning a multiple-displacement engine from a full-displacement engine operating mode to a partial-displacement engine operating mode, a base slip rate of a torque converter coupled to the engine engine is increased by a predetermined slip rate offset. The engine is then transitioned to partial-displacement mode upon the earlier of either achieving the desired offset slip rate, or once a maximum time delay has occurred since the slip rate offset was enabled. An offset slip rate is maintained throughout partial-displacement engine operation, and through a transition back to a full-displacement mode. The slip rate offset is removed or disenabled once the engine is again operating in the full-displacement mode. The slip rate offset is either a calibratable constant or is determined as a function of one or more suitable engine or vehicle operating parameters affecting vehicle NVH levels, such as engine speed and vehicle speed.

Torque converter slip control for multi-displacement engine

A method for estimating an output torque generated by a multi-displacement engine operating in a partial-displacement mode includes multiplying a measure representing a mass air flow through the engine's intake manifold by a engine-speed-based mass-air-flow-to-torque conversion factor, and thereafter summing the product with a torque offset value likewise based on engine speed data, to obtain a base indicated potential output torque. The base indicated potential output torque is then multiplied with a torque-based efficiency conversion factor representing at least one of a partial-displacement mode spark efficiency, fuel-air-ratio efficiency, and exhaust gas recirculation efficiency, and the resulting product is summed with a torque-based frictional loss measure to obtain the desired estimated engine output torque. The estimated engine output torque is particularly useful in determining whether a transition from the partial-displacement engine operating mode to a full-displacement engine operating mode is desired.

Airflow-based output torque estimation for multi-displacement engine

In an internal combustion engine adapted to operate in a cylinder-deactivation mode, a method for controlling the reactivation of a deactivated cylinder includes determining a difference between a torque request from a vehicle operator, and an estimate of a maximum engine torque achievable in cylinder-deactivation mode based at least in part on a current engine speed. The difference is integrated over time to obtain a torque request 'error.' A reactivation of the deactivated cylinder is triggered when the torque request error exceeds a first threshold value, which can be a calibrated value, a calibrated value adapted, for example, for driving style, or a value determined from a vehicle operating parameter such as vehicle speed. The use of the torque request error advantageously avoids reactivation of the deactivated cylinders in response to brief transients in the torque request signal that otherwise temporarily exceed the maximum achievable engine output torque.

Method and code for controlling reactivation of deactivatable cylinder using torque error integration

A method for enabling a transition of a multiple-displacement engine to a different engine operating displacement includes determining a temperature measure correlated with an instantaneous engine oil temperature at an engine start-up, for example, a detected engine coolant temperature at engine start-up; determining a start-up delay period based on the temperature measure, as with a lookup table of calibratable values; and enabling a displacement mode transition no earlier than when the engine run time since start-up exceeds the start-up delay period.

Method for enabling multiple-displacement engine transition to different displacement

A method for controlling the operation of a deactivatable valve lifter of an internal combustion engine includes determining a first measure of heat loss from one or more components associated with a given deactivated cylinder based, for example, on the number of engine cycles that have occurred since cylinder deactivation. The given cylinder is reactivated when the component heat loss measure reaches a threshold level, as by comparing the first measure to a first predetermined threshold value. After cylinder reactivation, the given cylinder can thereafter be deactivated only after the temperature of the components has been restored to a nominal operating temperature, for example, as inferred from a second measure, representing the heat generated within the given cylinder subsequent to cylinder reactivation, determined based upon engine mass air flow or fuel flow. In this manner, the respective temperatures of such engine components are maintained above a desired minimum temperature.

Method and code for controlling temperature of engine component associated with deactivatable cylinder

A method for determining an event-based hydraulic control delay in a multi-displacement system for an internal combustion engine, with which to adjust the triggering a solenoid in hydraulic communication with a hydraulically-deactivatable valve train component, includes retrieving either a first mapped value representative of a time-based hydraulic deactivation delay, or a second mapped value representative of a time-based hydraulic reactivation delay, based on a current engine speed and a current oil temperature, preferably using different lookup tables for each of the first and second mapped values. The method further includes determining a current time period between generated crankshaft position pulses, and dividing either the first value or the second by the first time period to obtain either an event-based hydraulic deactivation delay or an event-based hydraulic reactivation delay. The event-based delays are thereafter used to synchronize the timing of solenoid operation when deactivating or reactivating given engine cylinders.

Method and code for determining event-based control delay of hydraulically-deactivatable valve train component

A process for enabling cylinder deactivation in a multiple displacement engine involving oil aeration includes detecting engine speed. Once the engine speed has been determined, a delay period is established prior to enabling cylinder deactivation. The delay period is a function of whether engine speed exceeds a preselected threshold and an amount by which the threshold is exceeded. When the delay period expires, a request is generated for cylinder deactivation.

Transition control for multiple displacement 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

A method for characterizing an air flow target within an internal combustion engine. The method includes determining an air mass flow rate target, determining an engine speed term, and processing these terms to obtain an air flow target. The air flow target can be used as an input for vehicle controllers including those for controlling pressurized induction systems.

Air flow target determination

A method for characterizing an air mass flow rate target within an internal combustion engine. The method includes determining a reference air mass flow rate term, determining a predicted compressibility term, and processing these terms to determine an air mass flow rate target. The air mass flow rate term can be used as an input for vehicle controllers including those for controlling pressurized induction systems.

Air mass flow rate determination

A method for characterizing the friction losses within an internal combustion engine includes determining a start-up friction term, a mechanical friction term, a pumping loss term, and an adapted friction term to compensate for long-term frictional changes in the engine. A total engine frictional loss is determined by summing the start-up friction term, the mechanical friction term, the pumping loss term and the adapted friction term.

Engine friction characterization

A method for stabilizing the idle of an engine for a motor vehicle includes determining an engine rotational speed, modifying the engine rotational speed to define a friction engine speed, estimating a mechanical friction loss as a function of the friction engine speed, defining a torque request as a function of the mechanical friction loss and utilizing the torque request to control the engine at idle.

Stabilizing function for torque based idle control

A method for controlling the idle of an engine includes the step of determining a proportional airflow term by monitoring the difference between an engine idle speed and a target idle speed. In addition, an integral airflow term is determined. The method further includes the steps of determining a derivative airflow term by monitoring a rate of change of the engine idle speed and defining a limited derivative airflow term bounded by an upper limit and a lower limit. A total proportional, integral, derivative airflow is determined by summing the proportional airflow term, the integral airflow term and the limited derivative airflow term. The total airflow is then delivered to an engine control system.

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Grass Lake, MI, United States of America

Michael J Prucka