Two-Stroke Engine Throttle Merging for Emission Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Small-sized two-stroke engines face challenges with unburned hydrocarbon emissions due to simultaneous opening of exhaust and inlet ports during the scavenging phase, and existing stratified scavenging arrangements increase costs, weight, and complexity.
Innovation Solution
A two-stroke engine design featuring a fuel injector, shared air flow path with a throttle controlling both the air inlet and stratified scavenging intake, and optional components like a manifold, separation wall, and solenoid-controlled valve to manage air flow and reduce unburned hydrocarbon emissions while maintaining cost-efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If a stratified scavenging arrangement is implemented to reduce unburned hydrocarbon emissions, then emissions are reduced, but costs, weight, and device complexity increase
Solution Approach 1:
The patent merges the air flow control function into a single throttle body that controls both the main air inlet and the stratified scavenging intake. This consolidation eliminates the need for separate throttle devices for each air source, thereby reducing device complexity while maintaining the stratified scavenging arrangement's ability to reduce unburned hydrocarbon emissions through controlled air supply to the piston aperture.
2Object-generated harmful factors
If a stratified scavenging arrangement is implemented to reduce unburned hydrocarbon emissions, then emissions are reduced, but weight increases
Solution Approach 1:
The patent combines multiple air flow paths and control functions into a single integrated throttle body structure. By merging the control of main air inlet and stratified scavenging intake into one component, the overall weight of the engine is reduced compared to having separate throttle devices for each air source, while still achieving effective emission control through the stratified scavenging mechanism.
3Object-generated harmful factors
If a stratified scavenging arrangement is implemented to reduce unburned hydrocarbon emissions, then emissions are reduced, but manufacturing and assembly costs increase
Solution Approach 1:
The patent integrates multiple air flow control functions into a single throttle body component, reducing the total number of parts that need to be manufactured and assembled. This merging approach simplifies the manufacturing process and reduces assembly complexity and costs, while the stratified scavenging arrangement continues to effectively reduce unburned hydrocarbon emissions through the coordinated air supply to the piston aperture.
4Measurement precision
If multiple throttle devices are used to control air flow to air inlet and stratified scavenging intake separately, then air flow control precision is improved, but device complexity increases
Solution Approach 1:
The patent designs a universal throttle body that performs multiple functions by controlling both the main air inlet and the stratified scavenging intake through a single integrated structure. This multi-functional approach maintains air flow control precision for both air sources while eliminating the need for separate throttle devices, thereby reducing overall device complexity.
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 design effectively reduces unburned hydrocarbon emissions, simplifies maintenance, and allows for cost-efficient manufacturing and assembly, while providing adjustable engine response and characteristics without the need for additional throttle devices.
Implementation Method 1
a fuel injector configured to inject fuel into the crankcase
Implementation Method 2
a throttle configured to control the amount of air supplied to the air inlet and to the stratified scavenging intake
Implementation Method 3
clean air, i.e. air without added fuel, can flow from the stratified scavenging intake into the scavenging channel
Implementation Method 4
a piston arranged to reciprocate in the cylinder
Implementation Method 5
the increased pressure and temperature in the cylinder obtained by the combustion of fuel is partially converted into mechanical work supplied to a crankshaft of the engine
Data Source
AI summary
A two-stroke engine (1) is disclosed comprising a cylinder (2), a piston (3) arranged to reciprocate in the cylinder (2), a crankcase (5), a fuel injector (7) configured to inject fuel into the crankcase (5), an air inlet (9) connected to the crankcase (5), and a stratified scavenging intake (11) connected to the cylinder (2). The engine (1) comprises a throttle (13) configured to control the amount of air supplied to the air inlet (9) and to the stratified scavenging intake (11). The present disclosure further relates to handheld power tool (50) comprising an engine (1).