The Capitaine gasoline vaporizer places a ribbed inlet nozzle inside an exhaust-heated chamber. Fuel and air enter through a small valve; a separate larger valve admits additional air toward the engine. The cutaway shows these separate passages. The calculator estimates a stated fuel-heating and vaporization load, rather than the heat the historical device can actually transfer.
Gasoline Vaporizer Interactive Calculator
Enter fuel mass flow, an assumed liquid heat capacity, initial and target fuel temperatures, and latent heat. The target temperature is a fuel-state assumption, not a wall-temperature setting or a universal boiling point.
Equation Used
Heat capacity is in J/(kg·K), latent heat in kJ/kg, and mass flow in kg/s. The model heats a liquid with constant heat capacity and then applies one latent-heat value. Gasoline is a mixture, so real vaporization depends on composition and pressure over a temperature range. Air heating, wall losses, warm-up and any vapor superheat are excluded. Available exhaust heat and wall temperature are not calculated.
Heat crosses the nozzle wall
Hiscox’s figure 446 identifies the Capitaine arrangement. The outside of nozzle V has ribs, and an enclosing chamber carries exhaust around it. Fuel and air travel inside the nozzle, separated from the hot exhaust by the metal wall.
The small valve regulates the stream entering that nozzle. Farther downstream, a larger valve supplies additional air drawn in by the engine. The two valves therefore serve different intake paths.
The animation simplifies the original section. Gold markers follow the fuel-and-air passage, blue markers show additional air, and orange markers stay outside the ribbed nozzle in the exhaust jacket. The exhaust paths visible above and below the nozzle join around it outside the section plane. The illustrated valves open during a repeating intake interval and then close. Their timing and lift are prescribed, not calculated from springs, engine speed or pressure.
The ribs expose more metal surface to the exhaust, but surface area alone does not establish heat transfer. Exhaust conditions, wall properties, deposits and flow on both sides affect the actual rate. Marker colors and motion do not indicate a measured temperature or complete vaporization.
Understanding an early fuel-preparation device
This historical arrangement illustrates how exhaust heat can be transferred to an incoming fuel stream without mixing exhaust into that stream. It also separates the fuel-carrying inlet from the additional-air inlet.
For a particular tractor or engine, use its documentation for fuel choice, metering parts, starting provisions and operating instructions. A heat-load result cannot establish that an old engine is compatible with another fuel.
An assumed change in fuel enthalpy
The sensible term is qs = cp(Ttarget − Tin)/1000 in kJ/kg when heat capacity is entered in J/(kg·K). Adding the entered latent heat gives qtotal in kJ/kg. Multiplying by mass flow in kg/s gives the heat load in kW.
This is a simplified two-step state change: warm the liquid, then vaporize it using one assumed latent-heat value. The target fuel temperature is not the wall temperature. A finite temperature difference and sufficient heat-transfer area are needed to deliver heat from the exhaust, and neither is solved here.
Gasoline and kerosene contain multiple constituents. Their vaporization cannot generally be represented by one fixed boiling temperature and one latent heat independent of pressure or composition. For a real fuel, use suitable property or enthalpy data for the intended states. The entered ranges are comparison ranges, not recommended operating temperatures.
Example: a 1.675 kW fuel heat load
Use mass flow 0.0025 kg/s, heat capacity 2,100 J/(kg·K), initial fuel temperature 20°C, target fuel temperature 220°C and latent heat 250 kJ/kg. These are assumed values for the calculation, not measurements from the Capitaine motor.
The temperature rise is 200 K. Sensible heat is 420 kJ/kg, and total heat is 420 + 250 = 670 kJ/kg. Multiplying by 0.0025 kg/s gives 1.675 kW, approximately 5,715 BTU/hr. The kW tile rounds this to 1.68.
Doubling mass flow doubles the required fuel heat load without changing energy per kilogram. Increasing the assumed latent heat by 50 kJ/kg adds 0.125 kW at the default mass flow. These comparisons say nothing about whether the jacket can supply that heat.
Required heat is not available heat
The calculation estimates one demand term. Exhaust heating capacity requires exhaust flow and temperature, heat-transfer coefficients, geometry, wall temperatures and losses. Warm-up additionally requires the thermal mass of the assembly. None can be inferred from the fuel heat load alone.
A fuel film can remain partly liquid even when a bulk energy comparison appears adequate. Residence time, distribution and local wall conditions matter. Determining vapor fraction and mixture strength requires those flow and heat-transfer conditions as well as fuel properties.
Frequently asked questions
Where does the exhaust travel?
Around the outside of the ribbed inlet nozzle. The wall separates it from the fuel-and-air passage.
Why are there two inlet valves?
The small valve controls the stream entering the heated nozzle. The larger valve admits additional air toward the engine.
Is the target temperature a wall-temperature setting?
No. It is an assumed fuel temperature used in the sensible-heat calculation. Wall temperature and heat-transfer rate are not solved.
Are the default fuel properties universal gasoline values?
No. They are comparison assumptions. Actual properties depend on fuel composition, pressure and temperature.
Does the output prove that all fuel becomes vapor?
No. It gives the heat load for an assumed state change. It does not calculate the available heat, residence time or vapor fraction.
Does fuel flow change the valve timing?
No. It changes calculated heat power. The animation repeats an illustrative intake motion at a fixed display pace.
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