exam 3

Question 1

What motivates the transition from ICE vehicles to sustainable alternatives?

Answer 1

Long-term oil supply concerns, global climate change, and sustainability needs.

Question 2

List two pros of electric vehicles (EVs) compared to ICE vehicles.

Answer 2

Higher equivalent gas mileage (around 108 MPG), braking energy recovery.

Question 3

List two cons of electric vehicles (EVs) compared to ICE vehicles.

Answer 3

Higher cost and limited range.

Question 4

What is a hybrid electric vehicle (HEV)?

Answer 4

A vehicle that uses both an internal combustion engine (ICE) and electric motors.

Question 5

What is a plug-in hybrid electric vehicle (PHEV)?

Answer 5

A hybrid vehicle with a larger battery that can be charged from the grid or ICE.

Question 6

What does the hybridization ratio represent?

Answer 6

The ratio of electric motor power to total powertrain power.

Question 7

Describe a series hybrid vehicle.

Answer 7

Only the electric motor provides mechanical power to wheels; engine charges battery or generator.

Question 8

Describe a parallel hybrid vehicle.

Answer 8

Both electric motor and ICE can provide mechanical power to the wheels directly.

Question 9

What type of transmission does the Toyota Prius use?

Answer 9

A planetary gear set for continuous variable transmission (CVT).

Question 10

List a key technology challenge in HEVs.

Answer 10

Energy storage or regenerative braking systems.

Question 11

What are planetary gears used for in HEVs?

Answer 11

They function as an electric continuously variable transmission (e-CVT).

Question 12

What are three main operating modes of Toyota Prius hybrid?

Answer 12

Launch (electric only), cruising (engine-driven), and regenerative braking.

Question 13

What are some key reasons electric vehicles failed in the 1990s?

Answer 13

ICE vehicles became cheaper, more reliable, and charging infrastructure was not well-developed.

Question 14

What event in 1973 significantly influenced vehicle technology?

Answer 14

The 1973 oil crisis, prompting reconsideration of electric and hybrid vehicles.

Question 15

When was the first modern hybrid electric car introduced, and by which company?

Answer 15

1997, Toyota introduced the Prius.

Question 16

What was the major technological challenge addressed by Tesla’s introduction in 2008?

Answer 16

Improved performance, range, and reduced charging time of EVs.

Question 17

Explain the term ‘full hybrid’ and its typical hybridization ratio.

Answer 17

Full hybrids have large motors (50–75 kW), a hybridization ratio above 50%, and can run solely on electric power.

Question 18

Define ‘micro hybrid’ and its function.

Answer 18

Micro hybrids have small motors (~10 kW), a hybridization ratio below 50%, and primarily use motors for engine start-stop and regenerative braking.

Question 19

Explain a ‘mild hybrid’ vehicle.

Answer 19

Mild hybrids have intermediate-sized motors and hybridization ratios around 50%, combining features of full and micro hybrids.

Question 20

What is the role of regenerative braking in hybrid vehicles?

Answer 20

Regenerative braking recovers energy during deceleration to recharge the vehicle’s battery.

Question 21

What is the function of a planetary gear set in HEVs?

Answer 21

It splits torque and enables continuous variable transmission (CVT).

Question 22

List one advantage and one disadvantage of series hybrid vehicles.

Answer 22

Advantage: Engine operates at optimal efficiency; Disadvantage: Needs larger motors, hence higher cost.

Question 23

List one advantage and one disadvantage of parallel hybrid vehicles.

Answer 23

Advantage: Simpler structure, more efficient power usage; Disadvantage: Complex engine control.

Question 24

What defines a series-parallel hybrid vehicle?

Answer 24

It combines both series and parallel hybrid vehicle features, allowing flexible operation modes.

Question 25

Identify a primary goal of hybrid transmission design.

Answer 25

Achieving different operating modes efficiently with better fuel economy and reduced emissions.

Question 26

Why is thermal management crucial in HEVs?

Answer 26

To maintain battery and power electronics performance and longevity.

Question 27

What role does the government play in HEV development?

Answer 27

Governments provide support through incentives, regulations, and mandates for zero-emission vehicles.

Question 28

What recent global trend significantly boosted EV sales?

Answer 28

China's surge in EV adoption and sales.

Question 29

Name the four standard drive cycles used to evaluate HEVs.

Answer 29

Federal Highway Driving Schedule (FHDS), Federal Urban Driving Schedule (FUDS), EPA aggressive drive cycle (US06), and city/highway profiles.

Question 30

What are the main components of the Toyota Prius powertrain?

Answer 30

An internal combustion engine, two electric machines (motor and generator), and a planetary gear train.

Question 31

What is the primary advantage of using a planetary gear in the Toyota Prius?

Answer 31

It acts as a continuous variable transmission without needing a conventional gearbox.

Question 32

Explain the concept of hybridization ratio using a 50 kW motor and a 75 kW engine.

Answer 32

The hybridization ratio would be 50/(50 + 75) = 40%.

Question 33

What are the basic operations of a parallel hybrid system?

Answer 33

Both ICE and electric motor deliver power directly to wheels simultaneously or individually.