Intake Manifold Pressure Control via Volumetric Efficiency Actuator Prepositioning
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Solution Overview
Problem
During engine cylinder deactivation, intake manifold pressure rises due to air leakage, leading to inaccurate torque control and increased emissions when cylinders are reactivated, as the engine struggles to manage airflow and catalyst balance.
Innovation Solution
Adjusting the engine volumetric efficiency actuator to preposition it before reactivating cylinders, holding cylinder poppet valves closed to control intake manifold pressure and ensure fresh air is used in combustion, thereby reducing transient torque control issues and emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If cylinder poppet valves are held closed during entire engine cycle to deactivate cylinders, then fuel economy is improved, but intake manifold pressure rises due to air leakage causing inaccurate torque control
Solution Approach 1:
The volumetric efficiency actuator is prepositioned to a first position before the cylinders are reactivated. This preliminary adjustment of the actuator position prepares the intake system to properly regulate manifold pressure upon cylinder reactivation, preventing excessive pressure buildup and ensuring accurate torque control when combustion resumes.
2Adaptability or versatility
If cylinders are reactivated after intake manifold pressure rises, then cylinder deactivation is ended, but large amounts of air are inducted causing excessive torque production
Solution Approach 1:
The volumetric efficiency actuator is prepositioned to a first position before the cylinders are reactivated. This preliminary action adjusts the actuator to anticipate the upcoming cylinder reactivation, positioning it to properly regulate the intake manifold pressure and control the amount of air inducted when the cylinders become active again, thereby preventing excessive torque production.
3Power
If engine torque is controlled via retarding spark, then torque control is achieved, but accurate torque control during intake manifold pump down is difficult
Solution Approach 1:
The volumetric efficiency actuator is prepositioned to a first position before the cylinders are reactivated. This preliminary adjustment provides direct mechanical control over the intake manifold pressure regulation, offering a more precise and responsive method for controlling torque during the transition period compared to relying solely on spark timing retardation.
4Stress or pressure
If cylinder valves are reactivated allowing air to flow through engine cylinders, then intake manifold pressure is reduced, but engine response to accelerator pedal increases is reduced
Solution Approach 1:
The volumetric efficiency actuator is prepositioned to a first position before the cylinders are reactivated. This preliminary positioning enables the actuator to immediately begin regulating intake manifold pressure effectively once combustion resumes, reducing the time required for pressure reduction and thereby improving engine response speed to accelerator pedal inputs.
5Stress or pressure
If air flows to engine exhaust system during cylinder reactivation, then intake manifold pressure is controlled, but oxygen balance in catalyst is disturbed increasing tailpipe emissions
Solution Approach 1:
The volumetric efficiency actuator is prepositioned to a first position before the cylinders are reactivated. This preliminary positioning allows the actuator to immediately control the amount of air flowing into the intake manifold and subsequently to the exhaust system once combustion begins, maintaining proper oxygen balance in the catalyst and preventing excessive tailpipe emissions.
Data Source
AI summary
Systems and methods for operating an engine with deactivating and non-deactivating valves are presented. In one example, engine volumetric efficiency actuators are adjusted in response to a request to activate engine cylinders so that engine intake manifold pressure is drawn down quickly toward its normal state at the engine's present speed and torque.