Heated Throttle Plate for Carburetor Icing Prevention
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Carburetor icing in general aviation engines poses a significant risk due to temperature drops in the carburetor venturi, leading to ice formation on throttle valves, which can result in engine failure and catastrophic consequences, especially under conditions where conventional carburetor heat application is inadequate or inappropriate.
Innovation Solution
A heated throttle plate made from etched 304SS foil, electrically coupled and attached to the throttle valve, providing constant heat up to 150° F, supplemented by an engine oil pressure sensor for power, designed to prevent ice formation without affecting fuel-air mixture flow or requiring significant modifications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional carburetor heat is applied to prevent ice formation, then ice formation on throttle valve is prevented, but the fuel-air mixture becomes richer which decreases engine power
Solution Approach 1:
The heating element is applied locally only to the throttle valve plate surface where ice formation occurs, rather than heating the entire carburetor air passage. This localized heating prevents ice formation on the critical throttle valve surface while minimizing the thermal effect on the incoming air-fuel mixture, thereby maintaining engine power.
Solution Approach 2:
The patent replaces the conventional pneumatic heating system (using hot air from exhaust manifold) with an electrical heating system. This substitution allows for precise control of heating energy and enables localized heating of only the throttle valve plate, avoiding the rich mixture problem associated with conventional carburetor heat.
2Reliability
If manual carburetor heat control is used, then ice formation can be addressed, but pilot training and recognition of icing conditions are required which may not be available in all situations
Solution Approach 1:
The heating system is designed to operate automatically based on engine operating conditions. The heater is activated when the engine is running and idle or at low power settings, and deactivates when throttle is applied. This self-regulating system eliminates the need for pilot intervention or recognition of icing conditions, making the system foolproof and easy to operate.
Solution Approach 2:
The system uses feedback from the throttle position and engine operating conditions to automatically control the heating element. When the throttle valve is closed or partially closed (indicating idle or low power operation), the heater is activated. When the throttle is fully open, the heater is deactivated. This automatic feedback control ensures heating is applied only when necessary without requiring pilot input.
3Reliability
If heating element is added to carburetor, then ice formation is prevented, but device complexity increases
Solution Approach 1:
The heating element uses a thin flexible circuit board with heating traces that can be conformally attached to the curved surface of the throttle valve plate. This thin film approach minimizes the added thickness and structural complexity while effectively distributing heat across the throttle valve surface. The flexible nature allows adaptation to the existing carburetor geometry without requiring rigid structural modifications.
Solution Approach 2:
The heating element is integrated with the existing throttle valve plate assembly rather than being a separate component. The thin circuit board is attached directly to the throttle valve plate, and both are mounted together as a single assembly on the carburetor. This merging approach minimizes the number of separate parts and simplifies installation and maintenance.
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 solution provides continuous, automatic heat to the throttle valve, preventing ice formation during idle and take-off, enhancing safety by ensuring consistent engine power and reducing the risk of carburetor icing without adverse effects on fuel-air mixture flow or requiring extensive pilot training.
Implementation Method 1
a fused relay connection secured to an engine oil pressure sensor providing 14 volts and 35 watts for heating the throttle valve to 150° F.
Implementation Method 2
The venturi is used to change the fuel state and can drop the ambient air temperature by 70° F.
Implementation Method 3
Carburetor icing is caused by a fuel vaporization temperature drop associated with the pressure drop in the carburetor venturi.
Implementation Method 4
In order for the fuel to change from a liquid state to a gaseous state, heat must be taken from the air and added to the fuel, thus cooling the air.
Data Source
AI summary
A heated throttle plate formed from a strip of etched 304SS foil rated for 35 watts and formed into a predetermined pattern having a first end electrically coupled to a positive leadwire and a second end electrical coupled to a ground leadwire. The foil is positioned between layers of polyimide for encapsulating the foil therebetween. The leadwires are electrically coupled to a fused relay connection secured to an engine oil pressure sensor. In one embodiment the heater plate operates on 14 volts and 35 watts for heating the throttle valve to 150° F. A throttle shaft forms a channel for passage of the leadwires through the throttle body housing. The heater plate is constructed and arranged to conform to the shape of a stock throttle valve and attach thereto utilizing stock throttle valve fasteners.