The day approaches, more quickly than we may think, that the demand for automobiles will far surpass the supply that arrived with the Ring of Fire. Also, many of the cars from the future will have un-repairable breakdowns. A solution to the transportation gap may be the steam powered car.
Steam powered cars have several advantages. Most notably is that they do not need a separate transmission. There is enough torque in the steam engine that it is not necessary. A steam car needs only a steam generator, a reversing engine, a chassis and body, wheels and suspension, a brake system, and a steering mechanism.
The core of the vehicle is the generation of steam. The earliest steam cars had miniature boilers, wound in wire for strength, and fired with oil or solid fuel (coal or wood). Later, more advanced models had steam generators, also known as mono-tube or flash boilers.
A standard boiler small enough for a steam car has the need for all of the controls and safety measures of a large-scale steam operation, and is subject to the same dangers. That is: if mistreated they explode and do large scale damage to the area around them. A steam generator, on the other hand, is simply a tube wound in a coil with the heat applied to the coil. Water is introduced into the coil by a one-way valve. The water vaporizes upon hitting the hot coil and exhausts out the other end of the coil to the control valve and then on to the engine.
Unlike a standard boiler, the steam generator never has enough water in the coil to create a steam explosion if the coil melts down. Also, a steam generator makes steam instantly and does not need twenty or more minutes to “raise steam.” The biggest disadvantage of the steam generator is that it needs distilled or highly-treated water, or frequent cleaning. This need for cleaning can be mitigated by using a condensing regenerator for the exhaust steam, allowing as much as 1500 miles between water fill-ups. Water must also be force-fed into the coil, and so an injector pump will need to be coupled to the engine. If the generator is fed solid fuel, a forced draft fan may need to be incorporated. Solid fuels such as coal or wood burn more slowly, not explosively as do oil or gasoline.
The steam engine can be anything that produces around 15 horsepower. Normally this is a two- or four-cylinder compound (the steam gets used twice, once high pressure and once at lower pressure), with two to four inch cylinders. Valving must be present to allow the engine to be reversed, and also to control the speed of the vehicle. The engine is normally directly coupled to the drive axle as the steam engine has enormous starting torque.
The chassis and body can be quite simple, as they need only to have the capacity to support the cargo and a light-weight engine and generator set. A light buggy or farm wagon would serve very well as a model for this.
Suspension would follow modern automobile practices, with leaf springs and pneumatic shocks. The steering would probably be easiest with a tiller-controlled front wheel model. Steel rimmed wooden wagon wheels (with traction “tread” welded on for the drive wheels) would serve until better tires are available.
Such steam cars could be produced with all down-time methods except for the actual engines. Even the engines would be possible with “low end” or first generation machine tools and sand-cast parts. Therefore such a steam car would make a quick and dirty replacement for individual transportation needs without sidelining valuable production facilities.