Photo credit: lammersch
For many years now, private cars have been a favourite target of environmental campaigners, mainly due to the harmful emissions that all internal-combustion engines release into the atmosphere. Their effect was illustrated starkly several times in the 1970s when â€˜car-madâ€™ cities like Los Angeles and London were frequently shrouded in a thick, polluting smog. Car manufacturers have been working on improving their productsâ€™ environmental credentials for quite some time now. The most significant developments of the last quarter of a century include the rollout of unleaded fuel, as well as the mandatory fitment of catalytic converters, which remove many of the most harmful elements of vehicle exhaust fumes, to all new cars. But as the 21st century dawned, talk of diminishing oil supplies and the ongoing threat of global warming has incentivised both carmakers and governments to accelerate development of the technologies that will one day take over completely from those in the cars for sale today, which remain dependent on fossil fuels.
Hybrid cars, as the name suggests, represent a half-way house between traditional petrol- and diesel-engined models and the next generation of electrically propelled vehicles. Essentially, a hybrid car is one that combines an internal-combustion engine with an electric motor, powered by large batteries, to provide propulsion. There are two distinct forms of hybrid drivetrain: parallel and series. In a parallel hybrid, both the combustion engine and electric motor are connected to the transmission. Both engines are capable of powering the car, either at the same time or separately. In a series hybrid, only the electric motor is connected to the transmission, and it is solely responsible for propulsion. The combustion engine is connected to a generator to recharge the electric motorâ€™s batteries; it is not responsible for any motion. There are already a number of hybrid cars for sale right now from various manufacturers, with the most popular and recognisable being Toyotaâ€™s Prius, now in its third generation. Japanese rival Honda has recently launched its second-generation Insight hybrid, and Toyotaâ€™s upmarket brand Lexus offers hybrid versions of its luxury SUVs and executive saloons. These are all parallel hybrids, but General Motors in the US is currently developing the Chevrolet Volt, which should be among the first series hybrid cars to go on sale to the general public.
In the longer term, however, it is likely that hybrids, which still require some fossil fuel, will be superseded by exclusively electric-powered cars. Many governments worldwide are undertaking initiatives to get electric cars for sale to the public as soon as possible. Indeed, a Norwegian minister has proposed banning the sale of all new petrol and diesel cars from 2015! The main obstacle to the growth of electric cars is the fact that their batteries need to be recharged with mains electricity, but seeing as they cannot yet store enough energy for long-distance travel, extensive recharging infrastructure will have to be put in place before the use of electric cars becomes widespread. This is something governments will have to make happen, while the manufacturers concentrate on prolonging the life of batteries and improving their recharging speed. Governments will also have to ensure that their national power grids produce electricity using environmentally friendly resources such as water, wind or the sun.
But electric cars wonâ€™t have the roads of the future all to themselves. A rival technology has emerged in the shape of hydrogen fuel cells, arguably the most groundbreaking method of alternative propulsion currently being developed. A hydrogen-powered car has a fuel tank that is filled with hydrogen in the same way a petrol-engined carâ€™s tank is filled with petrol. The hydrogen reacts with oxygen inside the engine to produce electricity and water, which in turn power the carâ€™s electric motor. The Honda FCX Clarity is probably the most widely known hydrogen fuel-cell-powered car, as it has been on limited trial sale in the United States and Japan since late last year. Itâ€™s powered by a 134hp, 57-litre hydrogen fuel-cell stack, and also uses a 288-volt lithium-ion battery. On a full tank of hydrogen, the Clarity can travel up to 280 miles, and, most importantly, the only waste product it produces is water. As with electric vehicles, the growth of hydrogen-fuelled cars is dependent on a network of suitable refuelling points being rolled out.
With development of all these innovative technologies currently proceeding at breakneck pace, it looks likely that it wonâ€™t be too long before none of the cars for sale on dealersâ€™ forecourts have internal-combustion engines under the bonnet, something which will make a massive difference to the impact humans currently have on the planetâ€™s environment.