UPDATE: If you have been here before, check the bottom of this page for updates. (Updated 3-9-2000 and 5-29-2000).

Here is my rather crude sketch of the Brow Steam Car powerplant. I would have done a better drawing, but they won't let me have anything with sharp points in here! :) Most steam cars use a very similar steam and water system. As shown, the front of the car is on the left, and the back of the car is shown on the right. Some of the components will be located in slightly different positions from those shown in the drawing. The fuel tank, for instance, will be behind the rear axle and engine. For clarity, things have been drawn a bit different from their actual appearance. Much of the tubing is very compact and small in diameter, and fits neatly under the hood and body of the car. At the front of the car is the condenser, which is an ordinary automobile radiator. Exhaust steam from the engine flows through this and is cooled by air flowing through the radiator until it condenses back into water. The water flows out of the bottom of the radiator into the water tank. When the car is not running, there is no water standing in the radiator, and even while running there is very little. The water flows out as quickly as it is condensed. The radiator is hot whenever the car is running, and therefore cannot become blocked with ice. From the water tank, the water is sucked through a tube to a feed water pump located on one of the engine crossheads. This water pump is a double-headed plunger pump, and the plunger moves back and forth whenever the car is moving. Water flow is controlled by two electromagnetic inlet valves. When the boiler does not need water, these electromagnets (solenoids) are connected to electricity by a control switch, and they "grab" the steel ball inlet valves, preventing them from dropping onto their seats. The water then flows back and forth in the inlet suction line from the water tank. When the boiler does need water, the control system shuts off the electromagnets, and the ball valves are free to drop onto their seats, thus preventing the water from flowing back down the inlet line during the plunger delivery stroke. This causes the water to be pushed through the feed water line toward the boiler at a pressure of 500 pounds per square inch (psi). On the way to the boiler, the water flows through the feed water heater shown at the top of this drawing. This is a length of steel pipe inside an enlarged section of the exhaust steam line from the engine. Here the water absorbs some of the heat from the exhaust steam, allowing the steam to be condensed in a small radiator. This also recycles some of the exhaust heat, allowing the car to go further on water and fuel, and giving the car more power at top speed. After passing through the feed water heater, the water flows into the boiler, where it runs through 80 pounds of small-diameter coiled steel tubing heated by a gasoline burner and turns into steam at 500 psi and 700° Fahrenheit. This steam then passes through the throttle valve (shown here as a small box with a circle inside of it) and down a steam pipe to the engine. The throttle, operated by the driver's accelerator pedal, controls the amount and pressure of the steam going to the engine. This one simple control varies the speed and power output of the engine, similar to the accelerator pedal in a conventional automatic transmission car. In the engine, the steam is passed through special valves into and out of the cylinders, pushing pistons and connecting rods which turn the wheels and make the car "go". After doing work in the engine cylinders, the steam is exhausted from the engine at low pressure, passes through the feed water heater to preheat water going to the boiler, and finally condenses back into water in the radiator that returns to the water tank. This system allows the water to be recycled over and over, so that the car can go a long way on one tankful of water. Depending on how well the system is designed, the car can go from 200 to 1000 miles on a tank of water. Refilling it takes only a minute or so, and ordinary water is used, at the filling station or from a garden hose at home. The fuel system is very briefly sketched out above. In my car, it will consist of little more than a small electric fuel pump, which sucks fuel out of the fuel tank and pushes it through a hot vaporizing tube in the fire chamber, where the fuel boils into a hot vapor at 80 psi.. This vapor then flows out of one or more tiny jets and through a mixing tube, where it speeds up and creates a suction that pulls in air. The fuel vapor and air then mix together and burn in the middle of the boiler to heat the steel tubing and turn water pumped through the tubing into steam. There is also a small fuel tank above the boiler, which drips a tiny dribble of fuel into the burner to allow it to burn with a low flame, as a pilot light. When the main electric pump comes on, this tiny flame grows into a large flame powerful enough to boil 750 pounds of water per hour! The flame is completely sealed inside the boiler and, like the steam tubing, is completely safe. Explosions are impossible in this kind of boiler. Because there is no separate pilot light or spark device to "light" the fire, this system avoids the problems of "lightoff" experienced with many fan-type and other steam car burners. Like your home water heater, it is always burning. It thus starts up instantly and burns extremely cleanly. The electric fuel pump in my system is turned on and off by a switch in the control system. The fuel and water controls are some of the most important parts of any steam car. I have invented a very simple, low-cost, fully automatic control system which I believe will allow my steam car to run with much better performance and efficiency than a conventional car. Many other steam cars have achieved this goal, but the equipment they used required either a heavier or more expensive boiler than I want to build, or was more complicated and expensive than what I want to build. The cheaper and lighter the powerplant can be made, the more likely it is to be a success in today's competitive automobile market. The steam car fuel/water control system I have invented may be patentable, so I am going to keep the details secret until I have researched the patent situation. However, I enjoy discussing the general operation of my own and other steam cars, and hope that others will adopt some of these ideas in their own steam car designs. Much of this information has long been publicly available, though often very hard to find nowadays.

Update, 3-9-2000: FUEL SYSTEM CHANGED: After running into problems with the electric fuel pump originally planned, I have changed the fuel system. I am currently blueprinting a more traditional steam car fuel system, similar to the proven Stanley fuel system. My new fuel system uses a special type of hermetically-sealed diaphragm fuel pump to pump fuel into a small fuel pressure tank. The fuel pressure tank allows the burner to run a considerable time (as when warming up from cold) without running the fuel pump, and allows a simpler fuel pump, driven by the direct-drive engine. The fuel pressure tank is simply a rugged compressed air tank of the portable type (1-2 gallons), with fuel in its bottom kept at 80 psi by compressed air above it in the top of the tank. Similar pressure tanks are used in water systems for homes with their own water wells and pumps. These fuel pressure tanks have one problem: the fuel absorbs the compressed air over time, which reduces the amount of fuel the tank can deliver. In old-time steam cars, like Stanleys, this means adding compressed air at intervals. This is fun for antique steam car hobbyists, but is an unacceptable hassle for modern automobile drivers, so I looked for a way to eliminate the need for compressed air refills. At first I planned to enclose the air in a gas-impermeable flexible bladder to physically separate the air from the fuel. The air bladder idea had all kinds of construction and materials problems, however, so I invented a simple automatic device, a tiny diaphragm air pump and special regulator, to eliminate both the bladder and air refills and to automatically keep the right amount of compressed air in the fuel pressure tank at all times. It is much simpler and easier to build than it sounds. The fuel flow from the fuel pump to the fuel pressure tank is controlled by a simple fuel bypass valve. When the tank is at full pressure, any additional fuel from the fuel pump is automatically bypassed back to the nonpressurized main fuel tank. This wastes some horsepower, but the volume of fuel pumped is so small that the loss is minimal -- on the order of 1/50 hp! Another automatic valve shuts off the fuel flow from pressure tank to pilot light and burner when the fuel pressure drops below a preset level, around 60 psi. This prevents loss of air from the pressure tank, and leaves enough fuel in the pressure tank for warmup from cold, in case the car is left standing with the pilot on for more than a week (a rare occurrence). Both of these valves are located inside the fuel tank for extra safety in case of diaphragm or fitting failure. Such failure is very unlikely, but I believe in designing according to Murphy's Law: "anything that can go wrong, eventually will go wrong". In case of leaks or other problems (Murphy's Law again!), a hand-operated pump is provided, which pumps fuel, air, and water simultaneously from a single hand lever. This sounds primitive, but is actually much less of a hassle than jump-starting a drained or dead battery, and would be necessary less often than jump-starts in gas cars in real-world operation (we have all accidentally left our headlights on overnight!). If the car is properly maintained and used regularly, the hand pump lever might never be used. I have designed the valves to be multi-function, so overall this fuel system would be simpler than those in classic steam cars, and it would be as fully automatic and convenient as the fuel systems in modern gas cars. Overall complexity is only slightly more than that of a modern gas car's fuel-injection system, and I think the cost would be much less when the modern gas car's fuel-control electronics are factored in. My steam car's greater mechanical simplicity elsewhere more than makes up for the few extra bits in the fuel system. All moving parts of the fuel system are hermetically sealed with reinforced neoprene diaphragms, for safety, durability, and economy, and to eliminate fuel vapor emissions. A standard activated-charcoal vapor recovery cannister, vented to the burner via a flame arrestor fitting, keeps the main fuel tank at atmospheric pressure while safely and cleanly burning any fuel vapors which might otherwise escape. When the pilot light is shut off, a diaphragm valve closes the vent line to prevent fuel vapor escape. These simple, inexpensive features are necessary in any modern car using gasoline for fuel. This fuel system eliminates many difficult design/construction tasks, eliminates many potentially costly and troublesome components, and allows clean burning and steady firing without pressure pulses in the fuel supply. It also allows an instantly, precisely, and continuously variable firing rate, which simplifies accurate control of steam pressure and temperature in a lightweight steam generator. FEEDWATER CONTROL CHANGE: I have also replaced the solenoid-disengaged inlet valves in the water pumps with a low-restriction, on-off feed water bypass valve to control water feed to the boiler. My new feed water automatic valve works on the same principle as the piloted diaphragm water valves in washing machines, allowing high-pressure valve control with minimal mechanical force input. The main problem with the previously-planned solenoid-disengaged water pump inlet valves is that the required steel ball valves would be prone to corrosion and leakage and harder to make quiet-running. With a mechanical bypass valve downline from the water pumps, non-pitting nylon ball check valves with o-ring seats can be used in the pumps, eliminating corrosion, leakage, and noise. -------------------------------- (Inserted Update, 5-29-2000) Another problem with the solenoid valves is that they only give on-off control. This led to design difficulties in regulating the water flow to the boiler under some operating conditions. With the variable-opening feedwater bypass valve, the amount of water "leaked" out of the feedwater line (instead of being passed on to the boiler) can be precisely varied, which makes the water control system much easier to design for stable steam temperature. Bypass type feedwater systems are relatively inefficient, as they consume their full horsepower at any given speed no matter how much water is actually delivered to the boiler (which is determined by load). However, if the pump plungers are carefully sized, they can deliver enough water for any given load/speed within the system's range, while consuming well under 10% of the developed engine horsepower -- an acceptable loss. By analyzing the problem, I have discovered that very small changes in pump plunger diameter can have dramatic overall powerplant efficiency results with bypass type feedwater control systems. Careful design is extremely important. Another eye-opening design learning experience! It is possible to reduce pump horsepower loss, but this requires variable-displacement pumps, whose design difficulty, cost, and complexity are too high to justify the small horsepower savings. While researching this, I designed several types of variable-displacement feedwater pumps. (end inserted update of 5-29-2000) ----------------------------- (3-9-2000 Update, continued) Thus the fuel and water controls are now entirely non-electric in operation, and in a pinch the car will run perfectly with a dead battery or no battery at all! I am currently dimensioning the fuel system components, and all parts look pretty easy to make in the home shop, with minimal labor and tooling requirements and low-cost materials. Some of the valves are available off the shelf, but buying them would be substantially more expensive than building them. I am finding that designing components to combine low cost and easy buildability with safety and reliability in service is much more difficult than simply designing something that works!

	Powered by WebTV