Straddle-Type Vehicle Exhaust Pre-Catalyst Positioning
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing exhaust purifying systems for motorcycles, which rely solely on a main catalyst in the muffler, are insufficient due to lower exhaust gas temperatures by the time the gas reaches the catalyst, and the additional use of a pre-catalyst near the rider's leg poses a risk of heat damage.
Innovation Solution
Positioning the pre-catalyst within the exhaust pipe between the engine and the main frame, with a heat shield plate to protect the rider from radiation heat, and placing the main catalyst in the silencer to ensure efficient gas purification while keeping the pre-catalyst away from the rider's leg.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the pre-catalyst is disposed near the cylinder body for earlier activation of exhaust gas, then the temperature of exhaust gas increases and purification efficiency improves, but the pre-catalyst will be disposed proximate to rider's leg causing heat damage risk
Solution Approach 1:
The patent positions the pre-catalyst in the exhaust pipe between the engine and main frame, utilizing the vertical space dimension rather than horizontal positioning near the cylinder body. This spatial reconfiguration allows the pre-catalyst to be close enough to the exhaust opening for effective heating and purification, while simultaneously being distant from the rider's leg to prevent heat damage.
2Object-affected harmful factors
If the pre-catalyst is installed in a rear part of the exhaust pipe closer to the silencer, then the rider's leg is protected from heat, but efficient purification of exhaust gas will not be achieved
Solution Approach 1:
The patent resolves this contradiction by changing the positioning dimension from rearward (horizontal) to upward (vertical) between engine and main frame. This allows the pre-catalyst to maintain optimal distance from the exhaust opening for efficient purification while simultaneously achieving adequate separation from the rider's leg for heat protection.
3Object-affected harmful factors
If a heat insulating plate is provided on the outside of the exhaust pipe, then the rider's leg is protected from radiation heat, but the insulating plate itself may become very hot or melt
Solution Approach 1:
The patent extracts the heat protection function from a heat insulating plate and implements it through spatial separation. By positioning the pre-catalyst and exhaust pipe between the engine and main frame, the system eliminates the need for additional heat insulating plates, avoiding their potential failure modes while still protecting the rider's leg from radiation heat through distance.
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 configuration effectively raises the exhaust gas temperature for efficient purification and prevents heat damage to the rider by isolating the pre-catalyst from direct contact with the rider's leg, ensuring both effective exhaust treatment and safety.
Implementation Method 1
a pre-catalyst for raising the temperature of exhaust gas
Implementation Method 2
a main catalyst positioned downstream of the pre-catalyst for purifying the exhaust gas
Implementation Method 3
a heat shield plate disposed on the outside in a vehicle width direction of a portion of the exhaust pipe where the catalyst is installed
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The present application relates to a straddle-type vehicle (10) comprising a main frame (12) extending longitudinally of the vehicle, an engine (20) mounted on the main frame (12), and having an exhaust opening (42) disposed therein, an exhaust pipe (24) extending forward from the exhaust opening (42) and being curved and further extending rearward, and a catalyst (60) being disposed in the exhaust pipe (24), wherein the exhaust pipe (24) is positioned between the engine (20) and the main frame (12), as seen from above.