Engine Cylinder Deactivation Control for Load Balance
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Solution Overview
Problem
The dynamic skip fire technology for engine cylinder deactivation faces issues such as unbalanced cylinder loads, unstable operation, inability to configure for specific models, and complex control strategies, leading to unequal ignition times and recharge requirements.
Innovation Solution
A cylinder deactivation control method that determines the cylinder deactivation trigger moment, adjusts the working condition region based on crankshaft rotation speed and target torque, and calculates the fuel injection quantity for each cylinder, ensuring balanced loads and stable operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If dynamic skip fire technology is used for cylinder deactivation, then oil consumption and exhaust temperature are reduced in low-load conditions, but the number of ignition times of each cylinder becomes unequal and cylinder loads become unbalanced
Solution Approach 1:
The control method segments the cylinder operation into different groups (first group with first ignition fraction mode, second group with second ignition fraction mode) and assigns different ignition patterns to each group. This segmentation allows the system to achieve overall load balance by distributing ignition events evenly across all cylinders over time, while still enabling skip fire operation for energy reduction.
Solution Approach 2:
The patent implements periodic switching between different ignition fraction modes for different cylinder groups. By periodically rotating which cylinders are in which group, the system ensures that each cylinder experiences both higher and lower ignition frequencies over time, achieving long-term load balance while maintaining short-term skip fire benefits for energy reduction.
2Adaptability or versatility
If dynamic skip fire technology is used for cylinder deactivation, then the engine can operate in ignition fraction modes, but the control strategy becomes complex and electric control becomes difficult to implement
Solution Approach 1:
The control method dynamically adjusts the ignition fraction mode assignment for different cylinder groups based on real-time operating conditions. The system continuously monitors engine load, speed, and temperature, and dynamically switches between different ignition patterns and cylinder group configurations, enabling adaptability without requiring overly complex control logic through rule-based decision-making.
Solution Approach 2:
The patent changes key control parameters (ignition fraction mode, cylinder group assignment, active cylinder selection) based on predefined operating condition thresholds. By using parameter switching rather than continuous complex calculations, the system achieves adaptability to different operating conditions while keeping the control strategy implementable through standard electronic control units.
3Productivity
If DSF ignition fraction modes are used, then cylinder deactivation is achieved, but the number of ignition cylinders in each small cycle are not all equal, which is not conducive to achieving stable working state
Solution Approach 1:
Within each small cycle, the system intentionally creates asymmetric ignition patterns where different cylinder groups have different ignition frequencies. However, by designing the overall cycle to include multiple small cycles with complementary patterns, the asymmetry in individual cycles balances out over time, achieving both high cylinder deactivation efficiency in each cycle and stable overall working state.
Data Source
AI summary
In a cylinder deactivation control method of an engine, a cylinder deactivation trigger moment of a to-be-controlled engine is determined; a second cycle and a cylinder deactivation mode corresponding to the next first cycle are determined according to the crankshaft rotation speed at the cylinder deactivation trigger moment, the target torque at the cylinder deactivation trigger moment, and a second cycle and a cylinder deactivation mode corresponding to the previous first cycle at the cylinder deactivation trigger moment; the fuel injection quantity of the ignition cylinder in the next first cycle is determined.