Rotary Piston Engine Sealing and Inertia Management
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Solution Overview
Problem
Existing rotary-piston internal-combustion engines face issues with high inertia forces, deformation, friction losses, and lubrication problems due to large dimensions and inefficient sealing mechanisms, which limit their enlargement and utilization potential.
Innovation Solution
A rotary-piston internal-combustion engine design with a rotating block and stationary case featuring a high bore/stroke ratio, asymmetrical connecting rods, and sealing parts placed in grooves on the outer surface, reducing centrifugal forces and friction, and allowing for adjustable compression ratio and optimal combustion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the engine dimensions are enlarged to increase power output, then the power and displacement increase, but the inertia forces increase and deformation problems occur
Solution Approach 1:
The engine is divided into multiple independent three-cylinder units (first, second, third units) that can be combined in series. Each unit has its own rotating block with three cylinders arranged at 120-degree intervals, allowing the engine to achieve higher power through parallel combination rather than enlarging a single unit, thus controlling inertia forces.
Solution Approach 2:
The connecting rods are designed with asymmetric forked big-end eyes that fit into each other, with two asymmetric rods fitting together and one symmetric rod. This asymmetric design allows for optimized force distribution and balance in the multi-cylinder configuration, reducing the impact of inertia forces.
2Power
If the rotating block dimensions are increased to increase displacement, then the engine capacity increases, but the stationary case deforms and cooling becomes problematic
Solution Approach 1:
Instead of using one large rotating block, the engine uses multiple smaller rotating blocks (three per unit) with each containing three cylinders. This segmentation maintains structural integrity of individual blocks while achieving high displacement through combination of multiple units, preventing stationary case deformation.
Solution Approach 2:
The cylinders are arranged radially around the rotating block axis in three dimensions, with three cylinders per block at 120-degree intervals. This spatial arrangement allows compact packaging of large displacement engines without increasing the linear dimensions of individual rotating blocks, maintaining structural strength.
3Reliability
If the seal is placed in the rotating cylinder block to seal the cylinder space, then the sealing function is achieved, but the seal is exposed to centrifugal forces causing high friction and lubrication problems
Solution Approach 1:
Instead of placing the seal in the rotating cylinder block as in conventional designs, the seal is inverted and placed in the stationary case, sitting on the outer surface of the rotating block. This inversion removes the seal from the rotating reference frame, eliminating centrifugal forces and associated friction and lubrication problems.
Solution Approach 2:
The seal is extracted from the rotating block and relocated to the stationary case. This extraction separates the sealing function from the rotating mass, allowing the seal to remain stationary while still effectively sealing the cylinder space, thereby eliminating centrifugal loading.
4Ease of manufacture
If the bore/stroke ratio is kept at usual values, then the engine design is conventional, but the engine dimensions become too large
Solution Approach 1:
The engine employs an elevated bore/stroke ratio of 0.9 to 1.1 (naturally aspirated) or 1.0 to 1.2 (supercharged), deviating from conventional ratios. This parameter change allows the engine to achieve the required displacement with more compact dimensions, as the increased bore relative to stroke reduces the overall engine length and rotating mass.
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 design achieves smaller dimensions, reduced friction, improved sealing, higher engine speeds, and increased specific performance, enabling efficient operation with minimal mechanical losses and better combustion efficiency.
Implementation Method 1
between the crankshaft and rotating block there is gearing with a gear ratio Ncrankshaft/Nblock=−3
Implementation Method 2
The seal was then exposed to centrifugal forces that are caused by rotation of the cylinder block. That seal was then more loaded, there were high friction losses
Implementation Method 3
Smaller outer diameter of the rotating block is achieved thanks to high bore/stroke ratio and minimal length of connecting rods. That leads to small outer dimensions of the engine, better utilization of inner space and small weight. Small dimensions of the rotating block and relatively low speed of the rotating block with respect to the crankshaft allow to reach relatively small sliding velocities at the seal on the perimeter of the rotating block.
Implementation Method 4
Pistons are connected with a crankshaft by means of connecting rods. The crankshaft rotates at different revolutions than the rotating cylinder block and they are coupled by means of gearing.
Data Source
AI summary
A rotary-piston internal-combustion engine comprises a rotating block with three radially situated cylinders with pistons and an outside placed stationary case with two intake ports and two exhaust ports. Between the rotating block and the stationary case there are sealing parts and connecting rods, connected to one crank pin of a crankshaft. Between the crankshaft and the rotating block there is gearing for three times higher revolutions of the crankshaft in the opposite direction with respect to the rotating block. In the stationary case there are at least two spark plugs placed on the opposite sides. The bore of cylinders is 2 to 3.5 times higher than the stroke of pistons and all sealing parts with pressure springs that seal spaces of cylinders to the outer stationary case are placed in cavities in the stationary case.