Introduction to Physical Science

HYBRID VEHICLES

Introduction

In this WebQuest, students do some Internet research on hybrid electric vehicles (HEVs). They learn about the different types of hybrid electric vehicles, and about the parts that make up these different types. They also learn about the advantages of hybrid electric vehicles as compared to both conventional vehicles and all-electric vehicles. Students discover that hybrid electric vehicles produce just one-half the emissions of conventional vehicles. They also find out that hybrid vehicles have been around for quite some time; buses, locomotives, and even submarines can be considered hybrid vehicles because they rely on more than one source of power to operate. Finally, students answer some questions about hybrid electric vehicles, based on their Internet research.

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Task

While students are doing their Internet research, they will try to answer the set of questions given. Each web site has some of the answers to the questions, but several of the questions require information from two or more of the web sites. Many of the sites eventually link back to those listed on the student page. If time is limited, encourage students to spend more time exploring the first two web sites listed. They may find most of the information needed at these sites.

Objectives

Research hybrid electric vehicles and compare them to conventional vehicles.

Define hybrid electric vehicles and describe their component parts.

List the differences between series and parallel configurations in hybrid electric vehicles.

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Resources

Students will use the Internet links given to find out all about hybrid electric vehicles. They will learn about the advantages of hybrid electric vehicles as compared to conventional vehicles. They will identify the parts of hybrid electric vehicles, and describe the two types of configurations used in such vehicles. Students will also learn about the hybrid electric vehicles that are available today.

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Time

1 class period for Internet research and answering the set of questions

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Process

As students progress through the list of web sites, you may help them to focus on what they need to know to answer the questions given. Several of the web sites have links to other web sites with relevant information. If time allows, you may want to allow students to explore this subject further. Students may want to look into other types of hybrid vehicles, such as nuclear-electric submarines, diesel-electric locomotives, or gasoline-pedal power mopeds. However, this webquest is limited to hybrid electric vehicles, particularly those available for individual use.

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Evaluation

You may assign 10 points to each of the 10 questions for a total of 100 possible points. Theanswers to the questions are given below. You may rate the answer to each question by the following point scale: Excellent: 9-10 points; Very Good: 7-8 points; Good: 5-6 points; Satisfactory: 3-4 points; Poor: 1-2 points; and Unsatisfactory: 0 points.

Questions about Hybrid Electric Vehicles

1. A hybrid electric vehicle (HEV) is an electric car that also has a small internal-combustion engine and an electric generator on board to charge the batteries. HEVs combine the internal combustion engine of a conventional vehicles with the battery and electric motor of an electric vehicle.
   
   
2. There are several advantages: 1. The engines of an HEV can be sized to accommodate average load rather than peak load; this reduces the weight of the engine. 2. HEVs have greatly increased fuel efficiency. 3. HEVs have greatly reduced emissions. 4. HEVs reduce the need for petroleum and can use alternative fuels. 5. HEVs reduce the overall weight of the vehicle. 6. Cost of HEVs is comparative to that of conventional vehicles. 7. The regenerative braking capability of HEVs helps minimize energy loss from slowing down or stopping a vehicle.
3. HEVs can reduce the emissions by one-third to one-half that of conventional vehicles; later models will improve upon this.
   
   
4. Hybrid electric vehicles have these basic component parts: gasoline engine, fuel tank, electric motor, generator, batteries, and transmission. These are arranged into an energy storage system, power unit, and propulsion system.
   
   
5. batteries, ultracapaciters, or flywheels
   
   
6. spark ignition, engines, compression ignition direct injection engines, gas tubines, or fuel cells
   
   
7. electric motor in a series configuration or direct mechanical input to the vehicle propulsion system in a parallel configuration
   
   
8. In a series configuration, the internal combustion engine drives a generator that charges the batteries, which then power the electric motor. The electric motor directly turns the vehicle’s drive shaft. The series configuration works better for short trips of 35 km or less; it is more efficient but less powerful.
   
   
9. In a parallel configuration, either the engine or the motor can turn the driveshaft. No generator is needed because the motor serves as the generator. When the engine turns the driveshaft, it spins the motor when the clutch is engaged. Thus, the motor is a generator and it charges the batteries. The parallel configuration works better for long distance driving, especially on hills. It is more powerful, but less efficient, than the series configuation.
   
   
10. Both the Honda Insight and the Toyota Prius use parallel configurations. The Honda is a simplified parallel hybrid, and the Toyota is a parallel hybrid with some of the benefits of a series configuration.

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Conclusion

Using information gathered from the Internet, students should be able to answer the questions given about hybrid electric vehicles. Students should be able to answer the questions even if they previously did not understand how a conventional vehicle works. Several of the sites have clear diagrams and explanations of conventional, electric, and hybrid electric vehicles that provide enough detail for students to gain a simple understanding of this subject. Students should be able to give the reasons that they would or would not recommend that people purchase hybrid electric vehicles. Accept any answer as long as students can support their answers with facts from their Internet research.

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