Hybrid Cars - The Toyota Pruis

Considering the Toyota Pruis? Hybrid cars and electric cars are getting a lot more attention lately. Even those of use who wouldn’t normally consider buying a hybrid car are considering this viable alternative to our weekly $50 and more gas bills. Not only are hybrid cars an economical choice in more ways than just gas mileage, they are also a responsible way to help reduce the terrible emission effects on our environment.

This four-door sedan seats five, and the powertrain can accelerate the car to speeds up to 15 mph (24 kph) on its electric power alone. This design contributes to the Pruis’ superior city mileage as compared to its highway mileage. The Pruis drives a respectable 650 miles between fuel stops. For these reasons and more, the Prius was named the 2004 North American Car of the Year.

The Prius weighs in at a respectable 2,900 pounds (1,315 kg) and provides as much interior room and trunk space as a Toyota Corolla. Toyota designed the Pruis’ 1.5-liter engine to run at a maximum speed of only 5,000 rpm, which results in about 76 horsepower. By keeping their maximum engine speed this low, the car could be designed with lighter components that improve efficiency.

The Toyota Pruis caught my attention after my neighbor bought her second one not long ago. She had traded in a beautiful new Lexus sedan for the first Pruis, and as a long-time Lexus fan myself, I just had to go ask her what she thought of the Pruis. She was evidently really captivated by something to buy a second one. Basically her answer was that while she loved the Lexus, the cost of paying for it, maintaining it, and fueling it was making her feel just a bit irresponsible.

She owned the first Pruis for a year and got almost as much as she had paid for it in resale. In addition to the federal tax incentive she received and the low fueling costs, she calculated that it had cost her less than $300 per month in total ownership costs for that car. And she commutes over an hour one way every day. Well, I was spending more than that just on gasoline and I work at home. As a matter of fact, many states are even allowing Pruis owners automatic car pool lane access. The advantages just keep adding up on this car.

The Toyota Pruis, which appeared on the American market in 1997, has a current MSRP of $21, 725. It was designed with the goal of reducing emissions in urban areas. The Pruis adheres to California's super ultra low emissions vehicle (SULEV) standards. The Toyota Pruis can give you an additional 20 – 30 miles per gallon than the car you are driving now. That is a huge savings on gasoline, but does it mean that you have to compromise performance? First, let’s look at how a hybrid car performs its job.

The Pruis is a gasoline-electric hybrid car--a cross between a gasoline-powered car and an electric car. In a standard gasoline-powered car, a fuel tank supplies gas to the engine, the engine turns a t ransmission, and the t ransmission turns the wheels. An electric car relies on a set of batteries to provide electricity to an electric motor which turns a t ransmission, and then the t ransmission turns the wheels. Hybrid cars, like the Pruis, are a compromise, and sometimes a reconfigu ration, between these two designs. The Pruis is designed to significantly increase gas mileage, reduce gasoline emissions, and overcome the shortcomings found in an electric car (such as distance between re-fueling requirements and speed limitations).

The Toyota Pruis, and other gasoline-electric hybrid cars, have a unique design of gas and electric parts that work together for maximum efficiency and performance. Here’s a quick synopsis of what these parts are and how they works:

• Batteries – A hybrid car has batteries as its energy storage device for the electric motor. Unlike standard cars that are powered by gasoline that can only power a gasoline engine, hybrid cars have an electric motor that can deposit energy into the batteries as well as draw energy out of them.
• Generator - The generator is likean electric motor, but it only produces electrical power. In the Prius, the onboard generator automatically maintains the proper level of charge in the batteries, so the car never needs to be externally recharged.
• Electric motor – Hybrid cars have very sophisticated electric motors. Modern electronics provide the capability for the car’s electric motor to act as a motor as well as a generator. As needed, the electric motor can draw energy from the batteries to accelerate the car. Then in its capacity as a generator, it can not only slow the car down, but also return energy to the batteries.
• Gasoline engine - The engine in a hybrid car is very similar to those in most standard cars. The main difference is that the hybrid car’s engine is smaller and utilizes advanced technologies to decrease emissions and intensify efficiency.
• Fuel tank – Like in standard cars, the fuel tank in a hybrid is the energy storage device for the gasoline engine.
• Transmission - The transmission on a hybrid car performs the same basic function as the transmission on a conventional car. Some hybrids use conventional transmissions. The Toyota Prius, however, has a radically different design of transmission.

To accomplish the Pruis design team’s main goal of improving emissions in urban environments, Toyota developed their parallel hybrid powertrain, called the Toyota Hybrid System (THS). This powertrain contributes significantly by giving this parallel hybrid some of the benefits of a series hybrid.

The Prius was designed to optimize efficiency and decrease emissions in two key ways. First, t he engine is designed to run only at an efficient speed and load.As previously mentioned, the Prius can accelerate to a speed of about 15 mph before using its gasoline engine. The engine doesn’t start until the car reaches its optimal speeds, and after it does start, it operates in a narrow speed band.

Secondly, t he Pruis utilizes a unique power split device. This power split device is what allows the engine to remain in its most efficient load and speed range most of the time. It is basically a intelligent gearbox that connects the gasoline engine, generator and electric motor to each other. The power split device also equips the Pruis to function like a series hybrid, which means that the gasoline engine can charge the batteries and also provide power to the wheels as needed. The power split device also functions as a continuously variable transmission (CVT), which actually eliminates the need for a manual or automatic transmission. If that isn’t enough, this power split device also provides for the generator to start the engine so that the Pruis doesn’t need a starter.

In additional to this impressive performance, Toyota has established long warranties on their hybrid components. The Prius comes with an eight-year/100,000-mile warranty on the battery and hybrid systems. Maintenance costs of owning a Pruis are exceptionally good because the motors and batteries in hybrid cars normally don't require any maintenance over the life of the vehicle. If you do have to replace the batteries after the warranty expires however, be prepared to shell out several thousand dollars. Engine maintenance routines and costs should be comparable to standard cars, and because hybrids are built with regenerative braking, the brake pads should even last longer than the ones in the car you are driving now.

Sincerely,


Austin C. Davis
The Honest Mechanic

Photo  source http://www.toyota.com/prius/.

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