Hydrogen Refill Process with Pre-cooling and Pressure Estimation
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Solution Overview
Problem
Current hydrogen fueling processes for vehicles face challenges in controlling tank temperature and pressure to prevent overheating and overpressure, leading to inefficient refilling times due to strict SAE J2601 protocol limits, which require complex parameter fitting and excessive cooling or filling speed adjustments.
Innovation Solution
A process that sets a nominal gas filling rate, determines a maximum mass-averaged gas filling temperature, and adjusts the gas supply temperature to prevent overheating, while estimating the end-of-fill pressure to ensure safe and efficient refilling, using both hot and cold case conditions to optimize filling time and pressure without stringent temperature constraints.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the filling speed is increased to reduce refilling time, then productivity is improved, but the tank temperature exceeds safety limits due to insufficient pre-cooling
Solution Approach 1:
The patent applies preliminary action by pre-cooling the gas in the supply line before it enters the tank. A heat exchanger is used to cool the hydrogen gas to a target temperature (e.g., -40°C to -80°C) before filling, which prevents excessive temperature rise during high-speed filling while maintaining fast refilling rates.
Solution Approach 2:
The patent changes the temperature parameter of the supplied gas by using a heat exchanger to pre-cool the hydrogen to specific target temperatures. This parameter change allows the system to achieve both fast filling speeds and acceptable tank temperature rises, resolving the contradiction between productivity and temperature control.
2Temperature
If the cooling intensity is increased to control tank temperature, then temperature control is improved, but the filling time increases excessively due to strict temperature limits
Solution Approach 1:
Instead of applying cooling during the filling process, the patent applies preliminary cooling before filling by pre-cooling the gas in the supply line. This approach allows the tank to be filled rapidly without excessive temperature rise, eliminating the need for time-consuming cooling during filling while still achieving temperature control.
Solution Approach 2:
The patent skips the traditional approach of slow filling with intermittent cooling by rushing through the filling process at high speed with pre-cooled gas. The pre-cooling enables the system to skip the temperature control bottleneck that would otherwise require reduced filling speed.
3Temperature
If the pre-cooling is increased to prevent overheating, then temperature control is improved, but the gas density decreases leading to overpressure risks
Solution Approach 1:
The patent carefully controls the pre-cooling parameter by setting specific target temperatures (e.g., -40°C to -80°C) that are sufficient to prevent overheating during fast filling but not so low as to cause excessive gas density and overpressure. This optimized parameter change resolves the contradiction between temperature control and pressure management.
4Temperature
If the filling rate is reduced to control temperature rise, then temperature control is improved, but the refilling process becomes excessively slow
Solution Approach 1:
The patent applies preliminary cooling to the supply gas, which enables high-speed filling without excessive temperature rise. This eliminates the need to reduce filling rate for temperature control, maintaining high productivity while achieving temperature management.
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 approach allows for quicker and more efficient hydrogen refilling without exceeding temperature limits, reducing the need for excessive cooling and minimizing the complexity of parameter fitting, thereby improving the overall refilling process.
Implementation Method 1
cooling the gas to be supplied to the gas tank to the target gas filling temperature
Implementation Method 2
transfer of the compressed gas must be controlled in order to prevent overheating of the tank
Data Source
AI summary
A process for filling a gas tank made from a gas tank material with gas is provided, which process comprises the following steps: a) setting (S10) a nominal gas filling rate such that the tank is substantially completely filled within a predetermined filling time from a predetermined initial gas pressure value, b) determining (S20), assuming hot case tank conditions, a maximum mass-averaged gas filling temperature that will be reached at the end of the filling process, when filling the gas tank for the predetermined filling time with the nominal gas filling rate, c) selecting (S30) a target gas filling temperature not greater than the maximum mass-averaged gas filling temperature, d) cooling (S40) the gas to be supplied to the gas tank to the target gas filling temperature, e) starting the supply of gas to the gas tank, f) determining (S50) the actual mass-averaged gas filling temperature of the gas supplied to the tank, g) estimating (S60) an end-of-fill gas pressure from the actual mass-averaged gas filling temperature assuming cold case tank conditions, and h) terminating (S70) the supply of gas to the gas tank when the actual pressure of the gas tank is equal to the lower of the end-of-fill gas pressure and a maximum final fill pressure.