Intake Collecting Chamber for Atkinson Engine Backflow
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Solution Overview
Problem
Internal combustion engines using Atkinson valve timing experience backflow of charged intake air or fuel into the intake manifold, leading to increased temperature and reduced performance in downstream cylinders, due to which the compression ratio must be decreased to prevent knocking, further reducing efficiency.
Innovation Solution
Incorporating a collecting chamber between the intake manifold and cylinders, which is fluidly connected via an inlet and outlet, with a volume significantly larger than the intake port, to confine backflow and prevent it from entering the intake manifold, thereby maintaining optimal temperature and performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If Atkinson valve timing is used to increase engine efficiency, then the intake valve is held open longer to allow backflow of intake air or fuel mixture from the combustion chamber into the intake port, but this causes increased temperature in the intake manifold and reduced performance in downstream cylinders
Solution Approach 1:
The patent divides the intake system into separate segments by providing individual collecting chambers for each cylinder or group of cylinders. Each collecting chamber is separated from the main intake manifold, allowing backflow to be contained locally without affecting other cylinders. This segmentation resolves the contradiction by enabling Atkinson timing in one cylinder while preventing temperature increase in the intake manifold that would affect downstream cylinders.
Solution Approach 2:
The collecting chamber acts as an intermediary component between the combustion chamber and the intake manifold. It provides a buffer zone where backflow can occur without directly entering the intake manifold. The chamber is fluidly connected to both the intake manifold and the intake port, mediating the flow path to prevent hot gases from contaminating the main intake system while still allowing the Atkinson cycle to function.
2Reliability
If the compression ratio is decreased to prevent knocking caused by backflow, then knocking is avoided, but engine efficiency is further reduced
Solution Approach 1:
By segmenting the intake system with individual collecting chambers, the patent allows each cylinder to operate independently regarding backflow management. This enables the compression ratio to be maintained at optimal levels for each cylinder without compromising downstream cylinders, as backflow is contained within individual chambers and cannot trigger knocking in other cylinders.
Solution Approach 2:
The collecting chamber serves as a protective intermediary that prevents hot backflow gases from entering the intake manifold and affecting the charge in downstream cylinders. This mediation eliminates the need to reduce compression ratio for knocking prevention, as the intermediary structure physically isolates the backflow to the local chamber where it cannot cause knocking in other cylinders.
3Temperature
If a collecting chamber is added to confine backflow, then intake manifold temperature is maintained and downstream cylinder performance is enhanced, but device complexity increases
Solution Approach 1:
The patent merges the collecting chamber with the existing intake manifold structure, where the chamber forms an integral part of the intake assembly. The chamber is fluidly connected to the manifold and can be designed as a seamless extension or integrated component rather than a separate addition. This merging approach reduces device complexity by combining functions within a unified structure rather than adding discrete components.
Solution Approach 2:
The collecting chamber serves multiple functions simultaneously: it acts as a buffer for backflow, a thermal isolation barrier, a flow distributor, and an integral part of the intake manifold structure. By designing a single component that performs multiple functions, the patent reduces overall device complexity compared to having separate components for each function. The chamber's multi-functionality eliminates the need for additional complex mechanisms to achieve the same effects.
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
This solution prevents the increase in temperature within the intake manifold, enhancing the performance of downstream cylinders and overall engine efficiency by ensuring that the discharged mixture of fuel and air is confined to the collecting chamber, thus not affecting the intake manifold's temperature and density.
Implementation Method 1
The collecting chamber is configured to limit a backflow of the gaseous fluid from the intake port into the intake manifold
Data Source
AI summary
It is desired to increase the efficiency of an internal combustion engine (10) combusting a mixture of fuel and air. The internal combustion engine (10) may be operated with an Atkinson valve timing of inlet valves of a plurality of cylinders (26A-26D). To avoid a backflow of the mixture of fuel and air from the cylinders (26A-26D) back into an intake manifold (22) of the internal combustion engine (10), at least one collecting chamber (25A-25D) is provided between the intake manifold (22) and at least one of the plurality of cylinders (26A-26D) for limiting said backflow.