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Choosing greener cars
Vehicles are much cleaner running than they were 20 years ago. When buying a new vehicle, it is easy to buy green. Evaluate the impact of your new vehicle on the environment.
Ask yourself The Big Three (1) questions before buying:
- Does it have to be this big? Evaluate your needs carefully. Larger, heavier vehicles use more materials and require more power to drive. As a result, most have larger engines with poor fuel economies.
- How is the fuel economy? The amount of CO2 emitted by a vehicle is proportional to the amount of energy it uses. The better the fuel economy, the fewer the GHG emissions per kilometer. Bigger savings at the pump, too.
- What is the emission rating? Look for the Vehicle Emission Control Information sticker under the hood. It will tell you if the engine meets national low-emission standards (NLEV). Some dealerships remove these stickers. If so, ask a salesperson for vehicle emission information.
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Hybrids
Hybrid electric vehicles (HEV) combine a gasoline powered combustion engine with a battery-powered electric motor, resulting in twice the fuel economy of a conventional vehicle (2).
According to Manitoba Conservation, other HEV advantages include:
- Reduced smog-forming pollutants
- Reduced resource consumption and our dependency on fossil fuels
- Competitive pricing
- Exceptional gas mileage
- Similar safety and comfort features compared to conventional vehicles.
The combination of electric and combustion engine also offers the power, extended range and convenient refueling capability of conventional vehicles. The inherent flexibility of HEV's has lead the Clean Cities Program to identify them as excellent choices for both fleet and personal transportation (3).
Hybrid types
There are three basic types of hybrid:
In a series hybrid, the internal combustion (IC) engine never directly powers the vehicle. Rather, the IC engine drives the generator, and the generator can either charge the batteries or power an electric motor that drives the wheels (4). In other words, all the torque used to move the vehicle comes from the electric motor. The benefit of the series hybrid is that the IC engine drives the generator to run at optimal efficiency (5).
In a parallel system, the IC engine, the batteries and the electric motor connect to the transmission. As driving conditions change, both the IC engine and the generator/motor can supply power to the wheels, switching back and forth as needed (6). Power generated by the IC engine is typically used for highway driving, while the electric motor is used to assist in accelerating the vehicle (7).
In split HEVs there is no connection between the IC engine and the electric components. The engine drives one axle and the electric motor drives the other (8).
Regenerative braking
HEV's use regenerative braking to recapture braking energy (9). When the vehicle brakes to stop, the electric motor can work ìin reverseî, transferring the power created from braking to the generator. Electricity produced during this process can be stored in batteries or in ultra-capacitors. The recycled power can be reused to drive the wheels or displace engine operation so less fuel is burned, leading to fewer emissions.
There are a number of HEV's available in Manitoba: the Honda Insight and the Toyota Prius. Neither model fits the technical definition of any of the three types of hybrid. However, both are closer to a parallel hybrid in design. For more details, contact your local dealer.
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Electric vehicles
Electricity can be used in two ways as a transportation fuel:
- Stored for use in a battery
- Produced by an electrochemical reaction in fuel cells
When used to drive electric vehicles (EV's), batteries are the typical storage unit or "fuel tank" for electric power. Like a fuel tank as well, batteries can run dry and therefore have a limited range. However, instead of filling up at a gas station, the vehicle can be recharged by plugging into a recharging unit. Some electric vehicles can plug into any 110V household outlet!
Electric vehicles produce only two tailpipe emissions: heat and water.
Electricity is produced in fuel cells by electrochemical reactions. Hydrogen and oxygen are fed into a proton exchange membrane fuel cell stack and produce enough electricity to power an automobile. The production of electricity using fuel cells takes place without combustion. Fuel cell vehicle development is an ongoing process.
Existing electric vehicles are suitable for temperature-controlled environments such as factory floors, or warm weather attractions such as golf courses and tourist areas.
