Guide to Choosing a Green, Fuel Efficient Vehicle

A lot of progress has been made in the past two years in terms of the development of environmentally-friendly automobile options. So much so, in fact, that it can be quite confusing for green-minded car buyers to figure out which vehicles would be the best fit for their own personal driving needs and style. There are a large number of factors to take into account when trying to choose an efficient and capable ecologically-conscious vehicles. This article takes a look at each of the major fuel choices available on the market and discusses both their strong and weak points in an effort to guide buyers to a solid decision.

For a certain generation of drivers, the word 'diesel' conjures up the image of a smoky import belching clouds of blackness out of the tailpipe as it putters down the highway at sub-optimal speeds. Either that, or the twin stacks on an 18-wheeler doing much the same thing as they pull a heavy load up a steep hill. This negative perception, coupled with tough emissions laws helped to marginalize diesel vehicles in North America for decades. This is despite them thriving in Europe where they were recognized as inexpensive and efficient cars.

Things have now radically changed, and it's largely thanks to the difference that high technology has been able to make when it comes to producing clean power from small diesel engines. The biggest difference maker has been the sweeping adoption of direct injection. This design allows for diesel to be introduced into the cylinder through an injector, which in turn receives fuel from either an individual fuel line or a highly pressurized 'common rail'. When combined with turbochargers, this type of diesel motor can produce tons of low end torque along with smooth upper rpm power delivery, making for uncomplicated daily driving and highway cruising.

In terms of emissions, diesel engines produce a much lower amount of certain greenhouse gasses than a traditional gasoline motor. Modern technology has again intervened to take care of the particulate matter or soot that was once the cause of so much choking black smoke spewing from these types of vehicles. Filters and urea injection have worked wonders in terms of reducing the amount of soot that is actually produced by the vehicle. Drivers also have the choice to run biodiesel, which is a biologically-based fuel that runs in most standard diesel engines and produces extremely low emissions.

By using far less fuel than regular gasoline-powered cars and trucks, in combination with reductions in greenhouse gas production, diesel vehicles are a valid option for drivers interested in great mileage and a low carbon footprint. Some diesel cars are able to rival gasoline / electric hybrids when it comes to overall fuel consumption. Most diesel automobiles in the United States are imported by German car companies such as ( pictured), but also including luxury models from and . Domestic trucks from , , and increasingly offer the choice of a diesel engine, as well. With basic maintenance, most diesel engines will also far outlast a gasoline motor, and with the extra amount of torque produced by diesel engines, they are an excellent choice if you need to be able to pull a trailer or haul a heavy load while still doing your part to help the environment.

On the down side, diesel fuel is usually more expensive at the pump than regular gasoline. For those opting to use biodiesel, special equipment is often needed to prevent the fuel from congealing at lower temperatures. This can add an extra expense. However, the extra costs are often balanced out by the increased efficiency, meaning that there is usually little or no financial penalty involved in choosing a diesel automobile.

Biofuels are certainly not restricted to diesel engines. In the past 5 years, the emergence of Flex-Fuel (also known as E85 Ethanol) has created a new sector of the automobile industry which offers engines specifically designed to run on this alternative fuel. Flex-Fuel is created by blending gasoline with ethanol in a certain ratio that is delineated by the number following the 'E' in the fuel's designation. E85 fuel is the most common, and it is composed of up to 85% ethanol, with the rest being gasoline.

What makes E85 less harmful to Mother Nature than regular gas?

Any gasoline engine can be modified to use Flex-Fuel, but , and ( pictured) have stepped up to the plate in terms of providing cars and trucks which can run either E85 or gasoline right out of the box.

The primary disadvantage of using Flex-Fuel is a reduction in fuel economy. Asking a motor to run two different types of fuel makes it difficult to optimize it for the secondary option. Combined with the fact that ethanol contains less energy per volume than gasoline, drivers will see a reduction in mileage of around 25% on average when using this fuel. E85 is also not always readily available in some areas of the United States.

On average, E85 fuel is 11% cheaper than gasoline, which works to help minimize the extra cost of making the switch. However, much of this savings is a result of government subsidies, which has caused some to comment that transitioning to an ethanol-based infrastructure is unsustainable in the long term. It also doesn't offer the same level of emissions reduction as other alternative fuels. Flex-Fuel would seem to be an interim solution when it comes to environmentally-friendly vehicle design, and as such it is not the strongest option for buyers looking to make a green lifestyle change.

Hybrid vehicles debuted to a lot of hype at the beginning of the new millennium. The combination of an electric motor powered by a battery working alongside a gasoline engine promised to delivery exceptional fuel mileage. Early hybrids were limited to ultra-compact designs that weren't exactly practical, but recent advances have brought this technology to a wide range of vehicles. It is now possible to order entry-level, luxury and even full-size vehicles and SUV's in hybrid form.

Not all hybrids function in the same manner, nor do they all offer the same type of efficiency. When choosing a hybrid, it is important to understand which flavor would suit your needs the best. A full hybrid system shuts down the gasoline engine at stoplights and can travel on battery power alone for short distances. When the electric motor is used in conjunction with the gasoline unit during high speed operation, the system provides great fuel economy with minimal emissions. In contrast, some vehicles employ a hybrid system that shuts down the engine when stopped, but cannot actually move the vehicle on electrical power - the battery merely keeps the car's systems running. This was typically seen in heavier duty vehicles with larger engines, although by and large the market has moved towards full hybrids across all vehicle categories. Other 'mild' hybrids use an electric motor to assist during acceleration and take some of the strain off of the gasoline engine to help reduce fuel consumption.

On the horizon are so-called 'plug-in' hybrids. These are capable of charging their batteries from a standard wall socket, or a special 220 volt charging station. Scheduled to hit the market within the next 2 years, these vehicles offer the ability to use the battery to fully power the automobile regardless of the driving situation or speed. Some of these cars, such as the also provide a gasoline engine that can engage to charge the battery once the range is exceeded. The fundamental difference between plug-ins and other hybrids is that if so equipped, the conventional power plant at no time drives the wheels - it exists solely to keep the battery topped up. Many of these vehicles have no gasoline engine installed and therefore produce no emissions at all.

Commuters who are looking for a city car that will spend most of its time in heavy traffic would do well to go with a full hybrid system such as that employed by the , or the (pictured) while those who require more power might desire a mild hybrid design. If most driving will be done near the home, or if the commute to work is short enough, then it may be worth considering waiting for plug-ins to hit the market.

In most cases, the amount of fuel that might be saved over the long term when compared to a much cheaper diesel car or even a fuel efficient compact is negligible, or even non-existent. There is also the question of reliability. Most hybrid designs currently on the market have proven to be quite robust, but plug-ins are unproven in the marketplace and could present issues with battery life, particularly in areas where temperatures reach high and low extremes. It may be worth letting other buyers take the risk on the first generation of plug-ins, as many did when the Prius was first released in North America.