Variable Expansion-Ratio Engine Load Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Variable compression-ratio engines experience high fuel consumption when the expansion ratio is too high at low loads, leading to negative work and inefficient engine operation.
Innovation Solution
A variable expansion-ratio engine with an expansion-ratio adjuster, load detector, and controller that adjusts the expansion ratio to prevent negative work by lowering it when the load is below a predetermined value, and maximizing it for low-load operating ranges to improve fuel efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the expansion ratio is set high for low-load operating ranges to improve fuel efficiency, then fuel consumption is reduced, but negative work occurs when the load is below a predetermined value leading to high fuel consumption
Solution Approach 1:
The patent applies dynamics by making the expansion ratio variable rather than fixed. The expansion-ratio adjuster dynamically changes the expansion ratio based on real-time engine load conditions detected by the load detector. When load is below the predetermined value, the expansion ratio is lowered to prevent negative work; when load is at or above the predetermined value, the expansion ratio is maximized to improve fuel efficiency. This dynamic adjustment resolves the contradiction between maintaining high expansion ratio for efficiency and avoiding negative work at low loads.
Solution Approach 2:
The patent applies parameter changes by modifying the expansion ratio parameter in response to changing engine load conditions. The controller adjusts the expansion ratio parameter based on load detector input, changing it from a fixed parameter to a variable one. This allows the system to optimize fuel efficiency at appropriate loads while preventing negative work when loads are too low, directly addressing the energy loss problem.
2Productivity
If the expansion ratio is maximized for low-load operating ranges, then fuel consumption decreases, but the engine performs negative work when load is below predetermined value
Solution Approach 1:
The patent applies feedback by using the load detector to continuously monitor engine load conditions and providing this information to the controller. The controller then adjusts the expansion ratio based on this feedback. When the load detector signals that load is below the predetermined value, the controller reduces the expansion ratio to prevent negative work. This feedback mechanism ensures the engine operates efficiently across different load conditions while maintaining reliability.
Data Source
AI summary
A variable expansion-ratio engine includes an expansion-ratio adjuster configured to adjust an expansion ratio; a load detector configured to detect an engine load; and a controller configured to control the expansion-ratio adjuster. The controller controls the expansion ratio such that the expansion ratio at the time when the load is below a predetermined load value is set lower than that at the time when the load is equal to the predetermined load value.