Diesel Engine Piston Bowl Vortex Wake for Heat Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing diesel engines suffer from significant heat transfer to the piston, which increases energy loss and reduces efficiency, and thermal insulation coatings on the piston bowl are costly and prone to damage.
Innovation Solution
The fuel injector directs the fuel spray towards a target area on the piston bowl with a flow separation edge and area to create a vortex-filled wake, reducing direct heat transfer by forming a thermal insulation between the flame and the piston bowl.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a thermal insulation coating is applied to the piston bowl wall, then heat transfer to the piston is reduced, but the cost increases and there is a risk of coating damage
Solution Approach 1:
The patent introduces a vortex-filled wake as an intermediary fluid barrier between the flame and the piston bowl wall. This recirculating gas wake acts as a thermal mediator that reduces direct heat transfer to the piston surface without requiring any physical coating material, thereby eliminating coating reliability issues while maintaining thermal insulation benefits
Solution Approach 2:
The patent replaces the mechanical/physical thermal insulation coating system with a fluid dynamic system. Instead of using a solid coating layer to insulate thermally, the invention uses a controlled vortex flow field to create a thermal barrier, substituting a mechanical protection approach with a fluid-based thermal management approach
2Loss of energy
If a thermal insulation coating is applied to the piston bowl wall, then heat transfer to the piston is reduced, but manufacturing cost increases
Solution Approach 1:
The patent replaces the manufacturing-intensive thermal insulation coating process with a geometric design approach. The vortex-inducing structures are integrated into the piston bowl geometry, which can be manufactured using standard casting or machining processes, eliminating the need for separate coating application, curing, and quality control steps
Solution Approach 2:
The patent changes the approach from modifying material properties (adding coating material) to modifying flow parameters (creating vortex structures). By changing the geometric parameters of the piston bowl to induce specific flow patterns, the thermal insulation effect is achieved through fluid dynamics rather than material addition, simplifying manufacturing
3Power
If the fuel spray is directed to impinge on the piston bowl wall, then combustion efficiency is improved, but heat transfer to the piston increases
Solution Approach 1:
The patent applies local quality by creating a localized vortex-filled wake in the specific region between the flame and the piston bowl wall. This localized fluid dynamic structure provides thermal insulation precisely where needed - in the heat transfer path - without affecting the overall combustion process or flame impingement on the target area
Solution Approach 2:
The recirculating gas wake serves as a local intermediary that allows flame impingement for efficient combustion while simultaneously blocking the direct thermal path to the piston wall. The vortex structure creates a localized thermal barrier that decouples the combustion efficiency benefit from the heat transfer penalty
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
The vortex-filled wake effectively reduces heat transfer to the piston, enhancing engine efficiency while avoiding the costs and risks associated with thermal insulation coatings.
Implementation Method 1
The flow separation edge and flow separation area are configured to induce the formation of a vortex-filled wake between said flame and the flow separation area on the downstream side of the flow separation edge
Implementation Method 2
when gases of the flame pass the flow separation edge while being subjected to boundary layer separation
Implementation Method 3
The vortex-filled wake will form a thermal insulation between the flame and a part of the wall of the piston bowl
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
A diesel engine comprising at least one cylinder (1) with a piston (2) having a piston bowl (3). A fuel injector (6) is configured t o direct a fuel spray towards a target area (21) on an annular wall section (22) of the piston bowl so as to make a flame (20) formed by ignition of the fuel spray hit the target area. The target area borders, via a flow separation edge (23), on a lowered flow separation area (24) on said annular wall section so as to give this annular wall section a stepped configuration. Said flow separation edge and flow separation area are configured to induce the formation of a vortex-filled wake between the flame and the flow separation area on the downstream side of the flow separation edge when the flame flows from the target area, across the flow separation edge and over the flow separation area.