Two-Stroke Engine Valve Timing for Power and Weight Trade-off
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Solution Overview
Problem
Two-stroke internal combustion engines face limitations in efficiency and emissions due to suboptimal air-fuel mixture composition, leading to increased weight and dimensions when attempting to enhance power delivery, which is a challenge in hybrid propulsion systems for compact vehicles like motorcycles.
Innovation Solution
A two-stroke internal combustion engine design with inclined cylinders, a volumetric compressor, and a vent system with an electronic butterfly valve, along with optimized injector and exhaust valve configurations, ensures efficient air-fuel mixing and reduced emissions, achieving a compact and lightweight structure while maintaining high power output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the capacity of the internal combustion engine is increased to improve power delivery, then the power output increases, but the weight and dimensions of the engine increase
Solution Approach 1:
The patent changes the operational parameters of the two-stroke engine by implementing a specific valve actuation timing system that optimizes the air-fuel mixture composition. This allows the engine to operate more efficiently at its current capacity, delivering sufficient power without increasing engine size or weight, thereby resolving the contradiction between power output and engine weight.
Solution Approach 2:
The patent employs a hybrid propulsion system combining an internal combustion engine with an electric motor. This composite system allows the combustion engine to be smaller and lighter than a standalone ICE would need to be, while still achieving the required power delivery through the combination of both power sources.
2Power
If the capacity of the internal combustion engine is increased to improve power delivery, then the power output increases, but the dimensions of the engine increase
Solution Approach 1:
By optimizing the valve actuation timing and air-fuel mixture composition through parameter changes, the engine achieves better efficiency and power delivery from its existing displacement, eliminating the need to increase engine volume to achieve higher power output.
Solution Approach 2:
The hybrid propulsion system allows for a more compact combustion engine design since the electric motor contributes to the overall power delivery, reducing the volume required for the ICE while maintaining sufficient total power output.
3Use of energy by moving object
If the profile and travel of the pistons are changed to improve efficiency, then the efficiency increases, but the device complexity increases
Solution Approach 1:
The patent optimizes energy efficiency by changing the timing parameters of valve actuation rather than modifying piston geometry. This approach improves the air-fuel mixture composition and combustion efficiency without increasing the mechanical complexity of the piston system.
Solution Approach 2:
The patent replaces complex mechanical piston profile modifications with a controlled valve actuation system that uses timing and sequencing to achieve efficiency improvements, thereby avoiding increased mechanical complexity in the piston system.
4Object-generated harmful factors
If a hybrid propulsion system with an electric motor is implemented to reduce emissions, then the contaminating emissions decrease, but the weight of the propulsion system increases
Solution Approach 1:
The patent implements a hybrid propulsion system combining an electric motor with a two-stroke internal combustion engine. The electric motor handles low-speed, high-torque requirements and emission-sensitive operations, while the optimized two-stroke ICE provides supplemental power, together achieving reduced emissions with a more compact and lighter combined system than a conventional ICE of equivalent capability.
Solution Approach 2:
By optimizing the two-stroke engine's air-fuel mixture composition and valve timing parameters, the patent improves the efficiency and reduces the emissions of the combustion portion of the hybrid system, thereby reducing the overall emissions footprint without requiring a larger or heavier electric motor.
5Object-generated harmful factors
If a hybrid propulsion system with an electric motor is implemented to reduce emissions, then the contaminating emissions decrease, but the dimensions of the propulsion system increase
Solution Approach 1:
The hybrid propulsion system combines an electric motor with a compact two-stroke internal combustion engine. The optimized two-stroke design, with its improved air-fuel mixing and combustion efficiency, requires less displacement to produce the same power output, thereby reducing the overall volume of the propulsion system while maintaining the emission-reducing benefits of the hybrid architecture.
Solution Approach 2:
By optimizing the operational parameters of the two-stroke engine including valve timing and air-fuel ratio, the patent achieves better efficiency and lower emissions from a smaller-displacement engine, thereby reducing the volume required for the combustion portion of the hybrid system and offsetting the space occupied by the electric motor components.
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 a compact and lightweight design with improved efficiency and reduced emissions, suitable for hybrid propulsion systems in vehicles, offering high specific power and suitable for compact vehicles like motorcycles.
Implementation Method 1
a compressor (40) for aeriform substances, preferably of volumetric type... the compressor (40) being actuated by a rotation of a crankshaft (60) of the internal combustion engine (1) and being configured to deliver the compressed air to the combustion chamber under pressure
Implementation Method 2
an injector (32) disposed on the head (30) and configured to introduce fluidized fuel in the combustion chamber
Implementation Method 3
triggering the combustion of the air and fluidized fuel mixture contained in the combustion chamber
Implementation Method 4
actuating the exhaust valve (80) in such a way to free the exhaust conduit and permit the emission of the combusted gases from the combustion chamber
Data Source
Figure 1
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AI summary
An internal combustion engine (1) comprises a cylinder (20), an outlet port (25) in communication with the interior of the cylinder (20), a valve (80) suitable for intercepting a gas flow that passes through the outlet port (25), an inlet port (24) in communication with the interior of the cylinder (20) to introduce air in said cylinder (20), a piston (1000) mounted on a drive shaft (60). The piston (1000) slides inside the cylinder between a first position, wherein the piston (1000) closes the inlet port (24) and the outlet port (25), and a second position, wherein the inlet port (24) and the outlet port (25) are open. The internal combustion engine (1) comprises an injector (32) that injects a fuel in the cylinder (20), a compressor (40) that injects air in the cylinder (20) and an actuator that is configured in such a way to actuate the exhaust valve (80) to block the gas flow from the cylinder (20) when the piston (1000) is in the first position, and exhaust the gases from the cylinder when the piston (1000) is in the second position.