Cylinder Deactivation Control via Occupancy Detection
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Solution Overview
Problem
Noise, vibration, and harshness (NVH) constraints limit the fuel economy of vehicle powertrains, as deactivating engine cylinders or reducing torque converter slippage can increase efficiency but result in unpleasant torque pulsations and vibrational shocks for occupants, while reducing gear shift speeds may increase noise and vibrations.
Innovation Solution
A controller system that detects occupancy status using sensors and adjusts engine operating parameters, such as transmission schedules and torque converter lock-up schedules, to prioritize efficiency over NVH in situations where occupants are less exposed to engine noise and vibrations, allowing for cylinder deactivation and varying torque converter slippage based on occupancy configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If cylinders of the engine are deactivated to increase efficiency, then fuel economy is improved, but torque pulsations occur that are unpleasant for occupants
Solution Approach 1:
The patent applies dynamics by making the cylinder deactivation strategy adaptive rather than static. The control system dynamically adjusts which cylinders are deactivated based on real-time operating conditions including engine load, speed, and detected torque pulsations. This allows the system to optimize fuel economy while minimizing unpleasant torque pulsations by selectively deactivating cylinders based on current engine state and occupancy conditions.
Solution Approach 2:
The patent changes the parameter of cylinder deactivation from a fixed strategy to a variable one based on multiple parameters including engine operating conditions and occupancy status. The control system monitors engine parameters such as load, speed, and torque pulsations, and adjusts the deactivation strategy accordingly. Additionally, the system changes NVH compensation parameters based on occupancy detection, applying NVH compensation only when occupants are present in seats that would be affected by torque pulsations.
2Loss of energy
If slippage in the torque converter is reduced to increase efficiency, then powertrain efficiency is improved, but vibrational shocks are transmitted more to occupants
Solution Approach 1:
The patent applies dynamics by implementing a dynamic torque converter control strategy that adjusts slippage based on real-time conditions. The control system monitors occupancy status and engine operating parameters, then dynamically adjusts the torque converter lock-up clutch engagement. When occupants are detected in sensitive seats and engine conditions permit, the system allows increased slippage to reduce vibrational shocks transmitted to occupants, while maintaining efficient operation when occupants are absent or conditions require minimal slippage.
Solution Approach 2:
The patent uses the torque converter as an intermediary element between the engine and transmission to manage the transmission of vibrations. By controlling the lock-up clutch in the torque converter, the system can selectively engage or disengage the direct mechanical connection, thereby acting as a mediator that either transmits or isolates vibrational shocks from the engine to the occupants based on occupancy status and engine operating conditions.
3Loss of energy
If gear shifts occur at lower vehicle speeds to increase fuel economy, then fuel economy is improved, but noise and vibrations increase for occupants
Solution Approach 1:
The patent applies dynamics by implementing a dynamic transmission control strategy that adjusts gear shift schedules based on real-time occupancy status and engine operating conditions. The control system monitors for the presence of occupants in various seats and modifies the transmission shift points accordingly. When occupants are present in seats sensitive to NVH, the system delays gear shifts to higher vehicle speeds or adjusts shift patterns to minimize noise and vibrations, while allowing more aggressive shift schedules when occupants are absent to maximize fuel economy.
Data Source
AI summary
A vehicle includes a transmission; a torque converter coupled to the transmission; a controller in communication with the transmission and the torque converter; a driver seat, a passenger seat, and a back seat coupled to the transmission; and sensors configured to detect user occupancy of the seats. The sensors are in communication with the controller. The controller is programmed to receive data from the sensors, determine an occupancy status based on the occupancy data, set an engine operating parameter of one of the transmission and the torque converter based on the occupancy status, and control one or both of the transmission and the torque converter to operate according to the parameter.