Engine Bank Torque Transfer for Smooth Cylinder Deactivation
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Solution Overview
Problem
Existing CDA methods in internal combustion engines result in significant torque variations and increased emissions of unburned hydrocarbons (HC), carbon monoxide (CO), and nitrogen oxides (NOx) during transitions between activation and deactivation conditions, particularly when transitioning under constant torque generation conditions.
Innovation Solution
A method is employed to manage the transition between activation and deactivation conditions by modeling each bank of a two-bank engine independently, using models to estimate pumping losses and air trapped in cylinders, and adjusting fuel injection ramps to compensate for these losses and emissions, with additional measures like delayed fuel injection and increased urea-based reducing agent flow to minimize emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If CDA is activated to reduce pumping losses and improve fuel consumption, then fuel consumption is improved, but torque variations increase during transition
Solution Approach 1:
The patent applies dynamics by implementing a gradual transition mechanism where the deactivated bank is reactivated progressively over multiple combustion cycles rather than instantaneously. The control unit adjusts the activation state dynamically, transitioning through intermediate states where the bank is partially activated, thereby smoothing torque variations while maintaining the fuel efficiency benefits of CDA
Solution Approach 2:
The patent applies preliminary action by preparing the deactivated bank for reactivation before fully activating it. The control unit initiates a gradual activation process where fuel injection and valve timing are progressively adjusted over several combustion cycles, allowing the bank to ramp up its torque contribution smoothly and avoid sudden torque disturbances
2Temperature
If CDA is activated to maintain exhaust gas temperature, then exhaust gas temperature is maintained, but emissions of HC, CO, and NOx increase during transition
Solution Approach 1:
The patent applies dynamics by implementing a gradual transition mechanism where the deactivated bank is reactivated progressively over multiple combustion cycles rather than instantaneously. The control unit adjusts the activation state dynamically, transitioning through intermediate states where the bank is partially activated, thereby smoothing torque variations while maintaining the fuel efficiency benefits of CDA
Solution Approach 2:
The patent applies preliminary action by preparing the deactivated bank for reactivation before fully activating it. The control unit initiates a gradual activation process where fuel injection and valve timing are progressively adjusted over several combustion cycles, allowing the bank to ramp up its torque contribution smoothly and avoid sudden torque disturbances
3Power
If CDA is deactivated to reactivate all cylinders, then torque generation is improved, but emissions of HC, CO, and NOx increase during transition
Solution Approach 1:
The patent applies dynamics by implementing a gradual transition mechanism where the deactivated bank is reactivated progressively over multiple combustion cycles rather than instantaneously. The control unit adjusts the activation state dynamically, transitioning through intermediate states where the bank is partially activated, thereby smoothing torque variations while maintaining the fuel efficiency benefits of CDA
Solution Approach 2:
The patent applies preliminary action by preparing the deactivated bank for reactivation before fully activating it. The control unit initiates a gradual activation process where fuel injection and valve timing are progressively adjusted over several combustion cycles, allowing the bank to ramp up its torque contribution smoothly and avoid sudden torque disturbances
Data Source
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AI summary
Method of managing a changeover between an activation condition and a deactivation condition and viceversa of a bank (E1, E2) of an internal combustion engine (E) comprising a first (E1) and a second bank (E2), the method comprising a step of respectively gradual decrease or increase of a torque supplied by a first bank (E1) subject to deactivation or reactivation and a corresponding increase or decrease of a torque supplied by the second bank (E2).