1. Battery
   Hood
2. Ignition switch
   Steering wheel

Turning your key in the ignition initiates a chain reaction to get your car started. Typically, your key turns a lock which then allows power to flow from the battery to other ignition components and accessory features like air conditioning and radio.

1. gas fumes and air
   liquid gasoline
2. pure air
   carbon dioxide

Ignition occurs in the combustion chamber, where there is significant concentration of evaporated gasoline (and/or ethanol). The liquid itself does not serve as the burning medium.

1. To start your radio
   To ignite a spark
2. To provide forward momentum
   To charge your car battery

The job of a car's ignition system is to provide the spark that ignites the mix of air and fuel in a car's engine. Once ignition is successfully accomplished, the engine can burn fuel and provide the energy needed to drive.

1. 160 volts
   1254 volts
2. 20,000 volts
   1,000,000 volts

The spark has to have enough energy to jump through the air (called arcing) from one end of the spark plug to the other. Some cars produce 50,000 volts and up to accomplish a clean ignition, but 20,000 volts will do the job in most cases.

1. 120 mV
   3 V
2. 12.6 V
   20,000 V

Even though it takes at least 20,000 V to start a car's engine, that's way too much voltage to store in a car battery! Most cars use a standard 12.6 V and the current is transformed to meet the needs of ignition.

1. Mechanical Ignition System (MIS)
   Electronic Ignition System (EIS)
2. Distributorless Ignition System (DIS)
   All of the above

MIS was the first type of ignition system used in vehicles, but fell out of popularity with the rise of the EIS and DIS, which are considerably more reliable and efficient alternatives.

1. During intake
   During compression
2. During exhaust
   During combustion

Engine pistons rotate through four phases - intake, compression, combustion, and exhaust. The spark needs to occur during the compression phase to maximize energy release during the combustion phase.

1. To give electricity a pathway
   To arc the spark
2. To act as a transformer and increase spark voltage
   None of the above

The ignition coil is a small transformer that steps up voltage from the 12 V battery so that it can ignite a combustion reaction in the engine. Electricity from the car battery travels through the coil's many wire loops to increase in voltage.

1. AC (alternating current)
   DC (direct current)
2. Both AC and DC
   Neither

All cars use direct current in the ignition system and other electrically powered features, such as the radio and lights. The metal frame of the car acts as ground and returns the current to the car's negative battery terminal.

1. with a purely mechanical timing process
   with a computer
2. with remote assistance
   with motion detectors

A DIS is so efficient in part because the computer is able to control ignition spark timing much more accurately than previous methods. It's also easier to maintain.

1. spark plug
   rotor
2. distributor
   battery

Turning the key in the ignition switch allows electricity to flow from the battery through a resistor to the distributor, which is responsible for timing the ignition spark. It sends the spark to the correct cylinder at the correct moment, using the magnetic field created by moving current.

1. ignition voltage is too high for normal operation
   battery voltage needs to be directed through the resistor to protect car components from wear and tear
2. "cranking" the engine uses extra voltage
   all of the above

During ignition, full battery power is needed for "cranking" the engine and igniting a spark. After ignition, all of the battery's power is passed through a resistor that steps down voltage for the car's other systems.

1. It's easy to replace.
   It's less likely to be damaged.
2. It improves the resistor's longevity.
   It won't burn in a car fire.

Many manufacturers choose to position the primary resistor on a car's firewall because it's a simple fix if the resistor fails. Other manufacturers use a wiring harness that makes it more difficult to replace, but also improves the longevity of the part.

1. ignition switch
   condenser
2. spark plug
   computer

Only the spark plugs need to be routinely replaced, and even those frequently last for the first 100,000 miles or more. The computerized system has fewer components and usually they won't need to be replaced.

1. the harder you need to turn the key.
   the earlier the spark plug needs to fire.
2. the larger the ignition coil needs to be.
   the longer the spark needs to arc.

If the engine is running at a faster speed, then the spark needs to happen earlier so that there is enough time for ignition to take place before the combustion stroke!

1. Vacuum advance
   Centrifugal advance
2. Both
   Neither

The centrifugal advance adjusted timing using weights exposed to centrifugal force from the spinning shaft. Vacuum advance relied on the near-vacuum conditions created in the combustion chamber. Both were used to increase fuel efficiency.

1. The car makes a strange hissing noise.
   The car explodes.
2. Not enough voltage reaches the end of the plug and the cylinder misfires.
   Nothing at all.

Spark plug wires are more insulation than not, but over time the insulation will wear down. When this happens, the voltage traveling through the wire can degrade and cause the affected cylinder to misfire.

1. one
   two
2. eight
   sixteen

There are eight spark plugs - hence the name, V8. Interestingly, they don't always fire in order, and may rotate either clockwise or counterclockwise, depending on the make and model.

1. One
   Two
2. Four
   As many as there are cylinders

The rotor briefly touches the contact for each of the engine's cylinders, allowing electricity to move from the coil to the cylinder's contact point.

1. distributor cap
   combustion chamber
2. battery
   ignition coil

Spark plugs are embedded in the distributor cap, allowing them to rotate either clockwise or counterclockwise to service the engine's cylinders.

1. gold
   copper
2. aluminum
   platinum

While silver and copper are both excellent conductors, copper is less expensive and highly durable. So, automobiles, along with many other common electronics, use copper wires. Carbon is also often used.

1. the "points"
   a timer
2. nothing, it's immediately available
   a series of magnetically controlled levers

A contact point in the distributor is open or closed, depending on whether the magnetic field from the coil is large or small. It's timed by the rotating distributor shaft and cam.

1. It stops and waits for the path to reopen.
   It flows to ground.
2. It circulates in the point until it's open again.
   It reverses direction.

Current won't reverse its path or stop in place, so an alternate path must be provided when the route to a spark plug through the point is closed. Distributors are constructed so that the current can flow to ground until the point is open.

1. Higher voltage for ignition
   Replacement of points and condenser with electrical controls
2. Fewer maintenance needs
   All of the above

EIS allowed the ignition voltage to increase from 20,000 volts to numbers around 50,000 volts, making ignition more consistent. The new components also required less maintenance.

1. the distributor
   spark plugs
2. ignition coils
   the car battery

A DIS does not require a distributor and the many mechanical parts (like points, etc.) that come with it. Everything is automated and computer controlled.

1. in a ring around the distributor cap
   in a line
2. in bundles (typically three each)
   there's only one coil

Most distributorless ignition systems have coils arranged in packs of three, although some also have them mounted to each individual spark plug. It will cause multiple plugs to fire at the same time.

1. copper wiring
   air (the gap)
2. foam insulation
   plastic casing

In order to get a spark, it's necessary for the electricity traveling through the plug to jump from the center electrode to the ground electrode, igniting the surrounding atmosphere in the process. It's only possible because the electricity is attracted to the ground electrode, and the open air is the shortest path to get there.

1. direct ignition system
   frictionless ignition system
2. quick-spark system
   All of the above

A distributorless ignition system is also known as a "direct ignition system" because of its construction. Higher voltages are in direct contact with the coils, which in turn are in direct contact with the spark plugs.

1. electricity
   magnetism
2. mechanical timers
   rotating levers

Magnetism is what allows the components of a DIS to function in a timely manner, but an electronic sensor instead of a mechanical contraption responds to the magnetic fields created inside the vehicle .

1. making the spark as close to the combustion stroke as possible (retarding ignition)
   operating at a lower temperature
2. carefully controlling fuel injection
   all of the above

Operating at a lower temperature reduces nitrogen oxide emissions, and keeping the ignition spark as close to combustion stroke as possible reduces the overall car emissions.

1. gasket
   plug wire
2. ceramic insulator
   gap

The ceramic insulator prevents the electric current from diverting to the metal parts of the plug, thereby ensuring that it reaches the end of the plug and arcs as needed.

1. Master Timing Unit (MTU)
   Engine Control Unit (ECU)
2. Mesa Controller (MC)
   Plug Organizer (PO)

The Engine Control Unit, or ECU, controls the spark plug timing. Typically, it organizes the transistors which then control the sparks. It's also known as an EMS, or Engine Management System.

1. tanks
   airplanes
2. rockets
   It's never dangerous.

Rockets have very little tolerance for failed ignition because the gas build-up created can cause an explosion. Most rockets have several countermeasures to prevent explosions if a failed ignition occurs.

1. No, ignition is staggered for each cylinder.
   Yes, but only when the ignition coils are placed directly on the spark plugs.
2. Yes, that is how mechanical ignition systems always work.
   Maybe, it depends on the car model.

Mechanical systems must stagger ignition for each cylinder. The timing and order is determined by the distributor and how the car was manufactured.

1. A car can start with a dead battery.
   The energy from burning fuel isn't enough to get things started.
2. There is no electricity to provide a spark.
   All of the above

The battery is the car's only source of power until ignition is complete. If the battery's power is completely drained, there is no way to start a car without charging or replacing the battery.