Internal Combustion Basics Trivia Quiz

Answer: spark plug

Spark plugs are located near the top of the engine. Diesel engines have no spark plug, they rely on super high compression.

Answer: Open to allow gas/air to enter and for exhaust to exit

Engine performance is dependent on proper valve timing. If valves don't open/close at the proper time, the engine will lose power or won't run at all.

Answer: open the valves

Responsible for the "timing" of the valves (see above question). Cams open/close valves at the proper time for best performance. Cams can be tuned for street use, with optimal valve timing in the lower and middle engine speed range, or cams can be tuned for lots of power at high engine speeds, mainly for racing.

But technology is a wonderful thing, now some cars come with variable camshafts, and will use street cams on lower/middle engine speeds, then switch to race cams at high speeds!

Answer: camshaft

Without the cam, the engine would not know when to open/close the valves, creating engine anarchy! You may have answered a computer, but keep in mind, there were engines long before there were computers. And car computers will control much more than just the engine, like the ABS system, and transmission.

Answer: belt or chain

In general, chains are better because belts can snap. If the timing belt snaps during operation, SEVERE damage can occur. Chains do come out of adjustment, but will never break. If a belt snaps during operation, the piston can hit the valve, essentially ruining an engine.

When you buy a car with a timing belt, make sure it has a "non interference" motor. This means if your belt snaps, you wont have any engine damage. The cost to replace a timing belt can range from 200 bucks to over 1000 (depending on the make/model).

Answer: connecting rods

These parts need to be strong in order to take the raw force of piston operation. When people decide to build a racing engine, one of the first internal parts to be replaced are the connecting rods. Stock connecting rods (in most cars) won't handle high amounts of torque.

Answer: valve float

With weak valves, at high engine speed "valve float" occurs. The faster the engine speed, the faster the valves open and shut, and the springs allow the valves to return. Weak valve springs don't have enough strength to close the valve before it opens again (at high speeds), so the valve will just stay open, not allowing the engine to move any faster.

Answer: Forces more air/fuel mixture into the engine

Generally, turbos are more efficient because they use existing exhaust pressure to drive the turbine, while super chargers use the actual engine to drive the turbine. The problem with turbochargers is lag, because exhaust pressure has a build up first. Superchargers create boost right away. Also, heat can be a problem with turbos.

The turbo uses oil from the engine for lubrication. The turbine spins a lot faster than the engine and generates A LOT of heat. Therefore, one should use a high quality synthetic oil and install and engine oil cooler. Also, after hard running, the engine should idle for a few minutes to allow the turbo to cool and avoid "cooking" the engine oil. Once the heat problems are addressed though, a turbo will out-perform a supercharger.

Answer: dual overhead camshafts

Most modern cars have over head camshafts, they make the engine more efficient because over head cams don't require pushrods, so the camshaft is closer to the valve.

Answer: isometric

At the isometric point, all fuel is burned, and all the oxygen is burned. When this happens, the engine doesn't waste any fuel, or the engine isn't starved for fuel.

Answer: oxygen sensor

Probably the only emission control device that actually made the engine more efficient. They are usually located in the exhaust manifold, and monitor the exhaust gases and analyze the content, sending feedback to the engine, telling it if the mixture is too lean, too rich, or just right.

Answer: pushrods

They are still used today in some cars.

Answer: adding rubbing alcohol to gas tank

Rubbing alcohol will just make the engine run a little cleaner, but won't give a noticeable difference in power. The other 3 choices will all give a significant power boost.

Answer: nitrous oxide

Contrary to popular belief, nitrous oxide is not flammable by itself. When it is forced into a combustion chamber, the extreme heat separates the nitrogen and oxygen. More oxygen in the combustion chamber means more power because more fuel can be injected at the same time.

This is particularly useful in an internal combustion aircraft. There is less oxygen at high altitudes, so using nitrous oxide as such heights would compensate for the lack of oxygen in the atmosphere.

Answer: closer proximity to the valves, therefore eliminating pushrods which add rotational mass

Some will disagree, but it's simple physics! The valve train has fewer parts to operate, making the engine easier to turn over