Engine Controller Transient Phase Adjustment
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Solution Overview
Problem
Internal combustion engines with variable valve actuation devices face challenges in maintaining fuel economy when transitioning from a steady to a transient state, as output torque variations and calculation errors lead to suboptimal performance.
Innovation Solution
A controller that adjusts the intake camshaft phase by calculating a load change rate and setting a target phase to either a steady or transient state, with specific change amounts based on the load change rate, to prioritize output torque during transient states while limiting fuel economy deterioration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the target phase is set to a transient state phase that gives priority to output torque, then the transient characteristics are improved and the required load is achieved faster, but the fuel economy deteriorates
Solution Approach 1:
The controller dynamically changes the phase parameter based on the load change rate. When the load change rate is high (greater than or equal to threshold), the target phase is set to a transient state phase that prioritizes output torque. When the load change rate is low (less than threshold), the target phase is set to a steady state phase that prioritizes fuel economy. This conditional parameter change resolves the contradiction by adapting the phase setting to the actual transient state of the engine.
Solution Approach 2:
The invention introduces dynamic control by calculating the load change rate and adjusting the target phase accordingly. The system transitions between steady state phase and transient state phase based on real-time engine conditions, making the control strategy adaptive rather than fixed. This dynamic approach ensures optimal fuel economy during steady operation while providing sufficient torque response during actual transient conditions.
2Loss of energy
If the target phase is set to a steady state phase to prioritize fuel economy, then the fuel economy is improved, but the output torque increases slowly during transient states
Solution Approach 1:
The controller changes the phase parameter based on calculated load change rate. During transient states with high load change rate, the system switches to transient state phase settings that prioritize torque output. During steady states with low load change rate, the system uses steady state phase settings that prioritize fuel economy. This resolves the contradiction by applying different phase parameters according to actual operating conditions.
Solution Approach 2:
The system calculates the load change rate as feedback to determine whether to use steady state phase or transient state phase. This feedback mechanism allows the controller to detect actual transient conditions and adjust the target phase accordingly, ensuring torque response is improved when needed while maintaining fuel economy during steady operation.
3Productivity
If the transient state phase is changed by a large change amount to quickly increase output torque, then the transient characteristics are improved, but the fuel economy deteriorates excessively
Solution Approach 1:
The invention applies partial action by using two different change amounts. When the load change rate is high, a first (larger) change amount is applied to quickly improve transient characteristics. When the load change rate is low, a second (smaller) change amount is applied to limit fuel economy deterioration. This selective application of different action levels resolves the contradiction by matching the degree of phase change to the actual transient state.
Solution Approach 2:
The controller dynamically changes the phase parameter by different amounts based on the load change rate. The first change amount is used during significant transient conditions, while the second change amount is used during mild transient conditions. This parameter adaptation ensures that fuel economy is not excessively deteriorated while still providing adequate torque response.
Data Source
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AI summary
A controller for an internal combustion engine includes a controlling section that controls a variable valve actuation device such that the phase of an intake valve becomes a target value. The controlling section executes a process of setting the target value to a steady or transient state phase, a process of calculating a load change rate, and a process of setting a change amount of the transient state phase. The change amount of the transient state phase is set to a change amount when the engine operating state is a transient state and the load change rate is greater than or equal to a predetermined threshold. The change amount of the transient state phase is set to a second change amount that is less than the first change amount when the engine operating state is the transient state and the load change rate is less than the threshold.