Cylinder Deactivation Order Control for Driveline Torsional Vibration
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Solution Overview
Problem
Existing cylinder deactivation (CDA) technologies face challenges in managing noise, vibration, and harshness (NVH) in vehicles due to inadequate consideration of driveline torsional vibration, particularly in 6-cylinder engines.
Innovation Solution
A method for operating a 6-cylinder engine connected to a driveline that involves monitoring crankshaft speed and transmission gear selection to selectively operate in specific cylinder deactivation modes, such as Order 1.5 or Order 1, to avoid critical speeds causing driveline torsional vibration, using an electronic control unit to adjust engine operation based on predetermined differential speeds and gear changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If cylinder deactivation modes are implemented to improve fuel economy, then fuel efficiency increases, but driveline torsional vibration and NVH increase
Solution Approach 1:
The system dynamically adjusts engine operating modes (Order 1, Order 1.5, Order 3) based on real-time monitoring of crankshaft speed and transmission gear selection. The ECU selectively activates cylinder deactivation modes only when operating conditions indicate they will not excite driveline resonant frequencies, creating a dynamic adaptation strategy that resolves the contradiction between fuel economy and vibration control.
Solution Approach 2:
The invention changes the operational parameters of the engine by selectively deactivating specific cylinders (Order 1 deactivates 4 cylinders, Order 1.5 deactivates 3 cylinders) based on crankshaft speed ranges and gear selection. This parameter change allows fuel economy improvement while avoiding the specific operating conditions that generate harmful torsional vibrations.
2Loss of energy
If cylinder deactivation is used to reduce fuel consumption, then energy efficiency improves, but noise and vibration increase
Solution Approach 1:
The system implements a feedback mechanism where the ECU continuously monitors crankshaft speed and gear selection, then selectively applies cylinder deactivation modes based on this feedback. The control strategy uses feedback to determine when to switch between Order 1, Order 1.5, and Order 3 operations, ensuring fuel consumption is reduced only when vibration and noise levels remain acceptable.
3Object-affected harmful factors
If critical speeds are avoided to reduce driveline vibration, then NVH performance improves, but engine operating flexibility decreases
Solution Approach 1:
The invention segments the engine operating range into distinct crankshaft speed ranges and gear combinations, each with predefined safe operating modes (Order 1, Order 1.5, or Order 3). By segmenting the operational space, the system maintains engine flexibility within each segment while avoiding critical speeds, thus resolving the contradiction between vibration reduction and operating flexibility.
Solution Approach 2:
The system dynamically selects among multiple engine operating modes (Order 1, Order 1.5, Order 3) based on real-time conditions of crankshaft speed and gear selection. This dynamic mode selection preserves engine operating flexibility by adapting to different driving conditions while consistently avoiding critical speeds that generate driveline vibration.
Data Source
AI summary
A method for operating a 6-cylinder engine connected to a driveline including a transmission. The method includes: monitoring a rotational speed of a crankshaft of the 6-cylinder engine: monitoring a gear selection of the transmission; and operating the 6-cylinder engine in one of Order 3, Order 1.5 or Order 1 based on whether the selected Order avoids operating the 6-cylinder engine at a critical speed that corresponds to a natural harmonic frequency of the driveline, wherein priority is given to operating in Order 1.5, Order 1 then Order 3, in that order.