Michigan

102

The Henry Ford, Dearborn, MI

42° 18′ 12.9″ N, 83° 14′ 2.68″ W

“America’s Greatest History Attraction”

The name Henry Ford immediately evokes images of cars and the Model T, but Ford built more than cars. In Dearborn he constructed an enormous history museum with a fascinating collection of scientific and technological exhibits alongside American cultural artifacts.

The Henry Ford consists of a museum and an entire village of houses; because of the size of the site, it’s worth carefully planning your visit. The Henry Ford’s website has interactive tools for deciding what to visit and where to find objects of interest.

The museum contains entire homes and laboratories that were moved to The Henry Ford and put on display. The most interesting of these are the bicycle shop and home of the Wright Brothers and the reconstruction of Thomas Edison’s Menlo Park, New Jersey laboratory. There’s also Buckminster Fuller’s Dymaxion House prototype, a circular home made entirely of aluminum that could be delivered on a truck and was designed to be energy- and space-efficient.

Of course, it’s no surprise that the museum also has an extensive collection of cars and car-related memorabilia (including the neon sign used to illuminate the first McDonald’s fast food restaurant). And there’s a model of the (happily) never-created Ford Nucleon nuclear-powered car, plus the chance to take a ride in a restored Model T.

The transportation exhibit has a large collection of long-distance vehicles, including stage coaches, buses, and steam locomotives. At least one of the steam trains is in operation, pulling passengers around the site.

Steam power is well represented, with many working steam engines on display including a Newcomen engine taken from Cobb’s Engine House in England; it is the oldest surviving steam engine in the world. The steam power collection is the most fascinating part of The Henry Ford, but is sadly downplayed in favor of marketing attractions such as the IMAX theatre. Avoid the crowds and see Ford’s wonderful collection of working engines, which includes the enormous Highland Park Engine used to power one of his factories.

Some of the non-science artifacts on display include the car JFK was riding in when he was assassinated, the bus in which Rosa Parks was arrested for refusing to give up her seat, and the seat Abraham Lincoln was sitting in when he was shot.

A complete audio tour of The Henry Ford is available for download from the museum’s website free of charge. While at the museum, it’s also possible to tour the present-day Ford Rouge factory where the Ford F-150 truck is assembled.

Practical Information

Details of the museum (plus a lot of fancy marketing) are available at http://www.thehenryford.org/.

Two-Stroke and Four-Stroke Engines

Naturally, The Henry Ford also has a variety of gasoline engines on display. Gasoline engines can be largely divided into two types, two stroke and four stroke, depending on how the cycle of drawing gasoline into the cylinder (intake), compressing it, exploding it (ignition), and expelling the exhaust fumes is arranged.

In cars, four-stroke engines are used. Each stroke is a movement of the piston in the cylinder and has a single purpose: there’s one stroke each for intake, compression, ignition, and exhaust. Taken together, these four separate actions are known as the Otto Cycle after the German engineer Nikolaus Otto, who invented the internal combustion engine as we know it today.

In the Otto Cycle, a single cylinder in the engine starts with the piston at the top. The top of the cylinder has a pair of valves, one for the intake of fuel and the other for the exhaust fumes. The first step in the cycle is the intake of fuel. A mixture of gasoline and air is forced into the cylinder through the intake valve as the piston descends (Figure 102-1).

In the second part of the cycle, the piston raises again and compresses the air/fuel mixture with both valves closed (Figure 102-2). At this point the fuel is ready to be ignited.

Next, a spark is generated by a spark plug in the cylinder and the fuel explodes, forcing the piston down and generating power (this movement is called the power stroke; see Figure 102-3). (In contrast, a diesel engine [see page 66] has no spark plugs, but the engine goes through a similar cycle, with the fuel injected near the end of the compression stroke, and just air entering during the intake.)

After the explosion, the exhaust valve opens, and the piston comes up again and expels the fumes (see Figure 102-4). With the piston back at the top of the cylinder, the cycle can begin again.

In a car engine, the four pistons are typically linked together by a common rod called the crank shaft. As the engine operates, one piston performs the power stroke, moving the other pistons through different parts of the cycle. Each piston is at a different point in the four-part Otto Cycle, ensuring smooth operation.

In a two-stroke engine, the four parts of the cycle are performed by two piston movements. The cylinder in a two-stroke engine does not have valves; instead, it has a pair of holes (called ports) that allow fuel to enter (the intake) and fumes to exit (the exhaust). The ports are covered and uncovered by the piston during its movement.

With the piston at the top of the cylinder and a fuel/air mixture inside the cylinder, a spark plug causes an explosion that forces the piston down. When the piston is at the top, the two ports are covered by it and the explosion occurs in a confined space.

Figure 102-1. Intake stroke

Figure 102-2. Compression stroke

Figure 102-3. Power stroke

Figure 102-4. Exhaust stroke

As the piston descends, it first uncovers the exhaust port, allowing the gases in the cylinder (which are under pressure from the compression and explosion) to escape. Unlike a four-stroke engine, the space under the cylinder is important; it is filled with the air/fuel mixture, and as the piston descends this mixture is somewhat compressed, readying it to enter the cylinder. This one movement of the cylinder combines the power stroke and the exhaust stroke.

Eventually the piston uncovers the intake port, and the air/fuel mixture enters the cylinder and forces out whatever is left of the exhaust fumes. Then the piston moves up again and further compresses the mixture. This movement combines the intake and compression strokes.

Two-stroke engines are commonly used for portable machines like chain saws and lawn mowers, and for small vehicles like boats with outboard motors and mopeds. They are light, simple to manufacture, and easy to maintain because they have only two cylinders and no valves. However, they are also inefficient and polluting.

In a four-stroke engine, the intake and exhaust phases are carefully timed so that there’s no waste; in a two-stroke engine, the fuel/air mixture entering the cylinder inevitably leaks out of the exhaust since both are open at the same time. Also, in a four-stroke engine the area under the piston can be used for lubrication because it is not used for the cycle. In contrast, a two-stroke engine has to be lubricated by adding oil to the fuel/air mixture. Some of this oil burns at the same time as the gasoline, making two-stroke engines more polluting than four-stroke.