Variable Displacement Controller Cylinder Activation
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Solution Overview
Problem
Existing multiple-cylinder internal combustion engines face challenges in fuel efficiency under low load conditions due to excess torque output, which is converted to heat, and noise/vibration issues when selectively deactivating cylinders, requiring complex and costly damper mounting systems to mitigate these problems.
Innovation Solution
A variable displacement controller that uses ambient temperature and speed data to selectively activate/deactivate engine cylinders, determining torque limits and adjusting cylinder operation to optimize fuel efficiency while minimizing undesirable noise and vibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the number of combustion cylinders is increased to achieve high torque output and fast acceleration, then the engine can provide desirable performance targets, but fuel efficiency deteriorates due to excess torque output being converted to heat
Solution Approach 1:
The engine system dynamically adjusts the number of active cylinders based on real-time operating conditions such as vehicle speed, engine speed, and temperature. The controller selectively activates or deactivates specific cylinders to match the actual torque demand, transitioning from a static cylinder configuration to a dynamic one that optimizes fuel efficiency while maintaining required power output.
Solution Approach 2:
The system changes the operational parameter of cylinder activation status (active/inactive) based on varying operating conditions. By monitoring parameters such as vehicle speed, engine speed, and ambient temperature, the controller adjusts which cylinders are active, effectively changing the engine's displacement and torque output characteristics to match demand and improve fuel efficiency.
2Loss of energy
If combustion is selectively deactivated in one or more cylinders to improve fuel efficiency under low load conditions, then fuel efficiency is enhanced, but noise and vibration characteristics deteriorate and become more noticeable to passengers
Solution Approach 1:
The system applies different operational states to different cylinders based on their specific positions and the resulting vibration characteristics. When deactivating cylinders, the controller selects specific cylinders (e.g., alternating cylinders) to maintain balanced vibration patterns. This localized control approach ensures that fuel efficiency is improved while minimizing the generation and transmission of noise and vibration to the passenger compartment.
Solution Approach 2:
The system intentionally creates asymmetric cylinder activation patterns (e.g., activating cylinders 1, 3, and 5 while deactivating 2, 4, and 6 in a V6 engine) to balance the vibration forces. This asymmetric arrangement of active and inactive cylinders helps cancel out harmful vibrations while maintaining the fuel efficiency benefits of cylinder deactivation.
3Object-affected harmful factors
If damper mounting systems are added to isolate the passenger compartment from noise and vibration, then passenger comfort is improved, but device complexity, cost, and vehicle weight increase
Solution Approach 1:
Instead of adding complex damper systems to mitigate the harmful effects of cylinder deactivation, the invention converts the potential harm into a benefit by carefully selecting which cylinders to deactivate. The controlled asymmetric deactivation pattern actually reduces overall vibration generation compared to traditional approaches, eliminating the need for additional dampers while maintaining passenger comfort.
Solution Approach 2:
The engine system self-regulates its vibration characteristics through intelligent cylinder selection and deactivation patterns. By monitoring operating conditions and adjusting which cylinders are active, the system automatically minimizes harmful vibrations without requiring external damper systems, making the engine itself serve the function of vibration control.
Data Source
AI summary
Some embodiments are directed to a variable displacement controller for use with a vehicular engine. The controller can receive data indicative of ambient temperature and data indicative of at least one of engine speed and vehicle speed. The controller can determine engine torque value based on the engine speed, and determine a torque limit based on the ambient temperature and at least one of the determined engine torque value and the data indicative of vehicle speed. The controller can compare the engine torque value to the torque limit, and selectively activate/deactivate an engine cylinder based on the comparison between the engine torque value and the torque limit, such that the engine cylinder is deactivated if the engine torque value is less than the torque limit, and the engine cylinder is activated if the engine torque value is greater than or equal to the torque limit.