We've all heard of hybrids by now, and some will know a bit about what they are and what they can provide in terms of driving efficiency. Hybrid simply means a combination of two power sources. In today's market this mostly consists of a normal petrol combustion engine receiving support from an electric-driven motor, although some use a diesel engine. The electric motor helps the vehicle take off, and can run the car on electric power alone on the highway and in some low-load conditions. This helps to significantly reduce fuel consumption. Toyota, Lexus, BMW, Mitsubishi, Holden, Nissan, and Land Rover all currently offer a hybrid model in Australia, with more manufacturers jumping on board every year.
Gone are the days of the old carburettor system. Direct injection works by precisely spraying air and fuel directly into each cylinder (combustion chamber). Regular fuel injection or electronic fuel injection (EFI), as good as an invention it is, only sprays the mixture into the intake manifold and then it is sucked into each cylinder as the valve/s opens. The new technology has significantly improved fuel economy for modern vehicles as it is a more precise method of injecting fuel. The amounts of fuel needed are also measured and controlled more accurately for each cylinder. The technology is also adapted in modern diesel and turbo-diesel engines, sometimes called 'TDI' (turbo direct injection).
Variable valve timing
It sounds complicated, and it is. But it has become one of the most revolutionary technologies of the modern engine. It works by continuously adjusting valve control to the conditions to provide more useable power and torque throughout all parts of the rev range, helping to reduce emissions and lower fuel consumption by around seven per cent. All companies give it a fancy name. Honda calls it VTEC, BMW calls it VANOS, and Mitsubishi calls it MIVEC. It's also simply known as VVT.
When turbochargers were first introduced in road cars back in the 1970s, they were usually only associated with sports cars. Turbo soon became a buzz word that meant the product was 'cool' or sporty. Nowadays though, turbochargers have become an essential component in improving efficiency, lowering fuel consumption and reducing emissions. They work by blowing the air and fuel mixture into the engine using a fan which is driven by the exhaust gases. If you can imagine running along and getting puffed out. Imagine if fresh oxygen was blown into your lungs as you ran along, instead of gulping and panting for air. You'd run faster and for longer wouldn't you? That's kind of how a turbocharger works.
Almost all of today's car engines come with twin overhead camshafts, however, some still feature the old-school 'pushrod' setup. Every petrol and diesel engine comes with a camshaft. This is a solid tube with lobes on it. It rotates with the engine via a chain or belt, and opens and closes the valves. In older engines the camshaft was located down in the lower section of the block (where the pistons are), with a long rod going back up to the valves which are located in the 'head' on top of the block. This design isn't ideal as the rod loses some energy as opposed to the cam lobe pushing almost directly on top of the valves in an overhead cam design. Overhead cams have allowed engines to rev smoother and higher, and operate more efficiently.
This technology is predominately applied to larger engines such as V6 and V8s. When you're cruising along the freeway your car only needs a small amount of power to keep it going at a steady speed. If you're driving a V8 vehicle, for example, you don't require all that much power to keep the car going. Cylinder deactivation effectively switches off two or four cylinders, automatically, when there are low demands from the driver. Most systems out there will transform from eight to four cylinder combustion, and back again when needed, without the driver even knowing. It's all a seamless and smooth transition. The end result is the economy of a four-cylinder engine when driving on the highway. It's quite smart.
Electric vehicle (EV)
EVs are only just becoming more and more popular. These run solely on electric power, much like any other battery-operated device. The electric motor turns the wheels, propelling the car forward. The main benefit is zero fuel consumption and zero exhaust emissions. The drawback is the battery; when it runs out the car stops. This is fine for petrol and diesel vehicles as you can simply go to a fuel station to fill up before it runs out. With an EV there are not many recharging stations around, which means you can only drive an EV for a short distance. Various governments around the world are looking to update the infrastructure to cater for EVs.
Hydrogen internal combustion engine
Although there are experiments underway with hydro fuel cell technology, which is basically an electric vehicle (EV), some experiments are also being run with hydrogen combustion engines. These retain a similar engine layout as a petrol engine, only instead of using petrol, hydrogen is used. It fires in much the same way only it produces about 20 per cent more power. This is a significant technology breakthrough and hydrogen is completely clean to the environment, producing zero emissions from the exhaust. The only problem is scientists are still trying to figure out an effective way of storing hydrogen and making it as convenient as petrol in terms of petrol stations and so on.
The alternator is the generator that recharges a car's battery when the engine is running. It uses the engine's revolutions to turn a pulley and generate and convert rotational energy into battery charge. Although this is a great technology as is, every engine needs one to survive - it's a necessity. Active alternators are now being introduced in vehicles from Mazda and BMW which use a clutch system to allow the alternator to free-spin when the battery level is fully charged. This means the engine doesn't need to work that tiny bit harder to spin the alternator, saving fuel. It's a minute step but it certainly helps. Some systems also disengage the alternator when maximum engine power and acceleration is demanded by the driver, allowing the engine to serve up every bit of output it has without being weighed down.
LPG gas compatibility
Almost all petrol vehicles can be converted to run on LPG (liquid petroleum gas). LPG is not only more environmentally friendly than petrol, it's also considerably cheaper - you could fill the tank from empty for under $40. There are a handful of vehicles on the new car market that come factory-fitted with LPG, but most require an aftermarket tank installation and some engine modifications. It's an ingenious idea but unfortunately it is yet to fully take off. Taxi companies see the benefits, with almost all taxi cabs in Australia featuring an LPG setup.