Multicylinder Engine Ignition Timing Adjustment for Torque Smoothing
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Solution Overview
Problem
Multicylinder engines face challenges in suppressing vibration and noise during cylinder deactivation, especially when combustion occurs at uneven intervals, due to variations in output torque, making it difficult to accurately estimate the vibration developmental state and effectively control active vibration-proofing support members.
Innovation Solution
A multicylinder engine with a control unit that adjusts ignition timing and fuel injection in operating cylinders to smooth output torque, combined with an active mount that elastically supports the engine to cancel generated vibrations, effectively suppressing vibration and noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If cylinder deactivation is implemented to reduce fuel consumption, then fuel efficiency is improved, but vibration and noise increase due to uneven combustion intervals
Solution Approach 1:
The ignition timing is dynamically adjusted for each operating cylinder based on its position in the firing order and the deactivation pattern. Cylinders immediately subsequent to deactivated cylinders receive retarded ignition timing, while other cylinders receive advanced ignition timing, creating a dynamic compensation mechanism that smooths torque fluctuations and reduces vibration during cylinder deactivation
Solution Approach 2:
The invention changes the ignition timing parameter selectively for different cylinders during deactivation mode. By retarding ignition timing in cylinders following deactivated cylinders and advancing it in other cylinders, the system modifies combustion characteristics to equalize output torque across operating cylinders, thereby suppressing vibration and noise while maintaining fuel efficiency benefits
2Object-generated harmful factors
If active vibration-proofing support members are used to suppress vibration, then vibration control capability is improved, but control accuracy deteriorates due to inability to accurately estimate vibration developmental state under uneven combustion
Solution Approach 1:
The system performs preliminary action by adjusting ignition timing before combustion occurs in each cylinder. By pre-calculating and applying appropriate ignition timing adjustments based on the firing order and deactivation pattern, the system prevents torque fluctuations from occurring in the first place, thereby eliminating the need for complex real-time vibration estimation and control
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution smoothly adjusts output torque in operating cylinders during uneven combustion intervals, reducing complex vibrations and enhancing the suppression of vibration and noise, allowing for more accurate estimation and effective control of the vibration developmental state.
Implementation Method 1
an active mount that elastically supports a main body of the multicylinder engine, and generates vibration which cancels vibration that is generated during an operation of the multicylinder engine
Implementation Method 2
an ignition timing adjustment unit that adjusts ignition timing in each of the operating cylinders to smooth the output torque of the operating cylinders
Implementation Method 3
a fuel injection adjustment unit that adjusts a manner for injecting fuel into each of the operating cylinders to smooth the output torque of the operating cylinders
Data Source
AI summary
In some cylinder deactivation modes (e.g. virtual V-four operation mode in which two cylinders of a V-six engine are deactivated), ignition/combustion may take place in operating cylinders at uneven intervals. In this case, the output torque varies between the immediately subsequent operating cylinders after the deactivated cylinders in the firing order and the other operating cylinders. A multicylinder engine includes an ignition timing adjustment unit. When the ignition takes place in the operating cylinders at uneven intervals during cylinder deactivation, the ignition timing adjustment unit adjusts ignition timing in each of the operating cylinders to smooth the output torque of the operating cylinders.