Boxer Engine Scotch Yoke Split Cycle Compression
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Solution Overview
Problem
Internal combustion engines face challenges in reducing emissions and fuel consumption due to increased mechanical and thermal losses, complexity, and high production costs associated with split cycle processes and variable compression ratios, as well as vibrations and production expenses in variable valve timing systems.
Innovation Solution
A boxer engine design incorporating synchronized scotch yoke assemblies with auxiliary pistons and cylinders, allowing for two-stage compression and expansion processes, and adjustable compression ratios and valve timing using hydraulic or electric actuators, which reduces friction, vibrations, and production costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If split cycle processes are implemented to increase efficiency, then fuel consumption is reduced, but mechanical and thermal losses increase and production cost rises
Solution Approach 1:
The compression process is divided into two distinct stages: first stage compression in main cylinders and second stage compression in auxiliary cylinders. This segmentation allows each stage to operate at optimized pressure levels, reducing overall mechanical and thermal losses while achieving the desired fuel consumption reduction.
2Use of energy by moving object
If variable compression ratio is used to maintain stable efficiency factor, then overall efficiency increases, but device complexity and production cost increase
Solution Approach 1:
The compression ratio control is segmented into two independent systems: main cylinders with adjustable compression ratio via movable pistons, and auxiliary cylinders with fixed geometry. This segmentation simplifies the overall control mechanism compared to making all cylinders variable, while still achieving the required compression ratio adjustment for optimal efficiency.
Solution Approach 2:
The main cylinder compression ratio is made dynamically adjustable through movable pistons with variable positions, allowing real-time optimization of the compression ratio based on operating conditions, thereby maintaining stable efficiency factor across different load ranges.
3Power
If variable valve timing is implemented to increase torque and fuel economy, then engine performance improves, but production cost increases
Solution Approach 1:
The valve timing control is segmented and integrated into the compression ratio adjustment mechanism. The same movable components that adjust compression ratio also control valve timing, eliminating the need for separate variable valve timing mechanisms and thereby reducing production costs while maintaining torque and fuel economy benefits.
4Use of energy by moving object
If auxiliary cylinders are added for two-stage compression, then fuel consumption decreases, but device complexity increases
Solution Approach 1:
The auxiliary cylinders are merged with the main cylinder assembly in a compact integrated design. The auxiliary cylinders share common structural elements, cooling systems, and control mechanisms with the main cylinders, reducing the overall complexity increase that would normally result from adding separate auxiliary systems.
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 engine achieves increased efficiency, reduced emissions, and lower fuel consumption by utilizing the remaining pressure in main cylinders for additional power and starting compression strokes with compressed air, while maintaining a robust and precise adjustment mechanism.
Implementation Method 1
The present invention relates to an internal combustion engine with two-stage compression and expansion, incorporating synchronized scotch yoke assemblies with auxiliary pistons and cylinders
Implementation Method 2
The compression chamber comprises first and second check valves, wherein the auxiliary cylinder pair is adapted to suck in ambient air through the first check valve and compress and pump said air out through the second check valve
Implementation Method 3
internal combustion engine with low emission, for use in automobiles
Data Source
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AI summary
It is disclosed a boxer engine with two substantially mirror-symmetric engine sides (L, R) comprising a crankshaft (1) to which is connected, at least two main scotch yoke assemblies (110) each having one main piston (7) arranged inside one main cylinder (I, III; II, IV) of each engine side (R; L), and at least one auxiliary scotch yoke assembly (120) having a pair of auxiliary pistons (8) arranged inside a pair of auxiliary cylinders (V, VII; VI, VIII) of each engine side (R; L), wherein the main scotch yoke assemblies (110) are arranged synchronized on the crankshaft (1) and the at least one auxiliary scotch yoke assembly (120) is arranged 180° offset on the crankshaft (1), each auxiliary piston (7) defining an outer space and an inner space within each auxiliary cylinder (V, VII; VI, VIII), the inner space facing the opposite engine side (R; L), wherein, said inner spaces of each auxiliary cylinder (V, VII; VI, VIII) pair are in fluid communication and forming a compression chamber, said compression chamber comprises first and second check valves (69, 70), wherein the auxiliary cylinder (V, VII; VI, VIII) pair is adapted to suck in ambient air through the first check valve (69) and compress and pump said air out through the second check valve (70) into a main cylinder (I, III; II, IV) of the opposite engine side (R; L), and said outer spaces of each auxiliary cylinder (V, VII; VI, VIII) pair are in fluid communication and are receiving pressurized exhaust gas from a main cylinder (I, III; II, IV) of the same engine side (R; L).