EGEE 101 – Exam 2 Questions – Energy and Environmental Engineering –
practice material
Gasoline Engine - ANS ✔✔How it works: Internal Combustion
-Combustion of gasoline occurs occurs because of the mixing of a vapor of the gasoline with air and a
spark provided by a spark plug
-the battery in the car provides the electricity to create the spark
-The motor needs to turn over so the piston rises in the cylinder, compressing the air and gasoline
mixture, which is ignited by the spark.
-timing belt ensures that the timing is correct
-The resulting combustion produces hot gases, which drives the piston down providing the energy to run
your car
*4 Basic Engine Strokes
-Intake Stroke: air and gasoline (sprayed in a fine mist to permit better mixing of the air and gasoline)
enter the cylinder
-Compression: the piston head rises, compressing the air/fuel
-Combustion: the spark ignites the combustion/detonation, which rapidly pushes the piston down (via a
crankshaft connection; turns the vehicle's wheels)
-Exhaust: the products of combustion are vented out of the cylinder on the way to the catalytic
converter and the tailpipe.
Diesel Engine - ANS ✔✔How it works: Internal Combustion
*simpler than a gasoline engine
-air is allowed into the cylinder and the piston compresses it extremely (compressing a gas produces
heat)
-a mist of fuel is sprayed into the cylinder
-The air is so hot that the fuel instantly ignites and explodes without any need for a spark plug
-the piston pushes back out of the cylinder, producing the power that drives the vehicle or machine in
which the engine is mounted
, "What we are looking at is knocking behavior. If we get that undesirable, spontaneous combustion when
we compress the cylinders and the gasses and the fuel in the air, and it self-ignites, that is called
knocking. That is completely undesirable in a gasoline engine but it is exactly how a diesel engine works"
Electric-fuel Cell - ANS ✔✔How it works:
-electric cars rely on batteries that feed electric power to electric motors that drive the wheels directly
-makes power by using pressurized hydrogen gas fuel from a tank
-hydrogen gas fuses chemically with oxygen from the air to make water
-In the process electricity is released and this is used to power an electric motor
*turns potential energy in fuel to kinetic energy
Hybrid Engine - ANS ✔✔How it works:
*has a conventional gasoline engine for fast freeway driving and an electric motor for more economic,
pollution-free travel
-gasoline engine works the same as internal combustion
-batteries are charged up using energy to use the electric mode when going pollution free
Catalytic Converter - ANS ✔✔*Required by law to have a catalytic converter on gasoline engine cars
-Lowers emissions of CO, NOx, and hydrocarbons from the tailpipe
-Engine gases enter one end, pass through a bunch of catalysts, emerge from the other end
Step 1: CO → CO2 (Oxidation)
Step 2: NOx → N2 (Reduction)
Step 3: Hydrocarbons → CO2 and H2O (Oxidation)
-The 3 Catalysts used: Rhodium (Rh), Platinum (Pt), and Palladium (Pd)
The Chemistry of the Process:
-the catalyst allows the compound to reach its activation energy quickly without changing temp or
pressure
practice material
Gasoline Engine - ANS ✔✔How it works: Internal Combustion
-Combustion of gasoline occurs occurs because of the mixing of a vapor of the gasoline with air and a
spark provided by a spark plug
-the battery in the car provides the electricity to create the spark
-The motor needs to turn over so the piston rises in the cylinder, compressing the air and gasoline
mixture, which is ignited by the spark.
-timing belt ensures that the timing is correct
-The resulting combustion produces hot gases, which drives the piston down providing the energy to run
your car
*4 Basic Engine Strokes
-Intake Stroke: air and gasoline (sprayed in a fine mist to permit better mixing of the air and gasoline)
enter the cylinder
-Compression: the piston head rises, compressing the air/fuel
-Combustion: the spark ignites the combustion/detonation, which rapidly pushes the piston down (via a
crankshaft connection; turns the vehicle's wheels)
-Exhaust: the products of combustion are vented out of the cylinder on the way to the catalytic
converter and the tailpipe.
Diesel Engine - ANS ✔✔How it works: Internal Combustion
*simpler than a gasoline engine
-air is allowed into the cylinder and the piston compresses it extremely (compressing a gas produces
heat)
-a mist of fuel is sprayed into the cylinder
-The air is so hot that the fuel instantly ignites and explodes without any need for a spark plug
-the piston pushes back out of the cylinder, producing the power that drives the vehicle or machine in
which the engine is mounted
, "What we are looking at is knocking behavior. If we get that undesirable, spontaneous combustion when
we compress the cylinders and the gasses and the fuel in the air, and it self-ignites, that is called
knocking. That is completely undesirable in a gasoline engine but it is exactly how a diesel engine works"
Electric-fuel Cell - ANS ✔✔How it works:
-electric cars rely on batteries that feed electric power to electric motors that drive the wheels directly
-makes power by using pressurized hydrogen gas fuel from a tank
-hydrogen gas fuses chemically with oxygen from the air to make water
-In the process electricity is released and this is used to power an electric motor
*turns potential energy in fuel to kinetic energy
Hybrid Engine - ANS ✔✔How it works:
*has a conventional gasoline engine for fast freeway driving and an electric motor for more economic,
pollution-free travel
-gasoline engine works the same as internal combustion
-batteries are charged up using energy to use the electric mode when going pollution free
Catalytic Converter - ANS ✔✔*Required by law to have a catalytic converter on gasoline engine cars
-Lowers emissions of CO, NOx, and hydrocarbons from the tailpipe
-Engine gases enter one end, pass through a bunch of catalysts, emerge from the other end
Step 1: CO → CO2 (Oxidation)
Step 2: NOx → N2 (Reduction)
Step 3: Hydrocarbons → CO2 and H2O (Oxidation)
-The 3 Catalysts used: Rhodium (Rh), Platinum (Pt), and Palladium (Pd)
The Chemistry of the Process:
-the catalyst allows the compound to reach its activation energy quickly without changing temp or
pressure
