Propane Fuel Tank Thermal Control for Cold-Start Pressure Loss
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Solution Overview
Problem
Propane fuel tanks in internal combustion engines experience pressure drops during cold ambient conditions, leading to insufficient fuel supply and engine starting failures.
Innovation Solution
A thermal management system that automatically restarts the engine in response to fuel tank pressure conditions, using coolant circulation and fuel circulation to maintain fuel tank temperature and pressure for reliable engine starting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the engine is shut down after operation, then fuel consumption is reduced and emissions are minimized, but the fuel tank temperature decreases and pressure drops below the threshold required for reliable engine starting
Solution Approach 1:
The system performs preliminary heating of the fuel tank using coolant circulation before the engine shutdown occurs. The controller monitors fuel tank pressure and temperature, and activates the coolant pump to circulate warm coolant through the fuel tank heating passages when pressure drops below a threshold, ensuring the fuel remains in a state suitable for starting even after the engine shuts down.
Solution Approach 2:
The system uses the engine's own coolant as a heating source to maintain fuel tank temperature. The coolant, which is already warm from engine operation, is redirected through the fuel tank heating passages, allowing the system to self-regulate and maintain fuel properties without requiring external heating sources or additional energy input.
2Reliability
If coolant is circulated to the fuel tank to increase temperature, then fuel vapor pressure increases and engine starting is enabled, but engine restarts are required which increases fuel consumption and operational complexity
Solution Approach 1:
The controller continuously monitors fuel tank pressure and temperature sensors, and activates coolant circulation only when pressure drops below a predetermined threshold. The system automatically deactivates the coolant pump when pressure returns to the acceptable range, creating a feedback-controlled system that maintains fuel properties only when necessary, thereby minimizing unnecessary engine restarts and fuel consumption.
3Reliability
If the engine automatically restarts to heat the fuel tank, then fuel temperature increases and pressure is maintained, but the system complexity increases and repeated restarts reduce fuel economy
Solution Approach 1:
The system uses the existing coolant circulation system, which is already part of the engine's thermal management infrastructure, to also heat the fuel tank. By making the coolant system multi-functional (serving both engine cooling and fuel heating purposes), the patent avoids adding separate heating equipment, thereby reducing overall system complexity while maintaining reliable fuel supply pressure.
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
Ensures consistent engine starting capability even in extreme cold by dynamically managing fuel tank temperature and pressure, reducing the need for repeated engine restarts and improving fuel economy.
Implementation Method 1
coolant warmed by operation of the restarted engine is circulated to the fuel tank to increase a temperature of the fuel tank
Implementation Method 2
coolant warmed by operation of the restarted engine is circulated to the fuel tank
Implementation Method 3
fuel in the fuel tank is circulated to the engine to be warmed by operation of the restarted engine
Data Source
AI summary
Systems and methods for thermal management of a propane fuel system are disclosed that include controlling a pressure of a fuel tank so that a fuel supply is available for starting of the engine even during cold ambient conditions.