Hail the hybrid?
As the motor industry charges on, the world is in dire need of alternatives to fossil fuels. GAVIN MYERS takes an in-depth look at one current solution, the hybrid, and asks if it’s really all it’s cracked-up to be?
Use some imagination and try to guess how many vehicles are in the global car park right now. I’ll tell you: approximately one billion! And within the next 10 years it will increase to
1,2-billion … think about that figure: 1 200 000 000!
Mix that colossal total with the fact that fossil fuel is rapidly being depleted, and it’s obvious that fuel efficiency and emissions are two key topics that the motor industry simply has to grapple with.
Gone are the days where (most) vehicles were punted on their 0-100 km/h acceleration times and largely academic top speeds. Today, it’s all about l/100 km and how many grams of carbon dioxide (CO2) are spat out the tailpipes per kilometre (g/km). The lower both those figures are, the better.
At this point, it should be mentioned that the motor vehicle is not the sole (or main) antagonist when climate change and dwindling resources are on the agenda. Industry – especially in countries (like South Africa) where coal is the main source of energy – is a far larger contributor of harmful greenhouse gases.
Indeed, It is estimated that cars are responsible for anything from one or two percent, to 20% of the world’s greenhouse gases – though the actual figure is widely debated. In its 2009 report on hybrid electric vehicles, the United Nations Environmental Programme (UNEP) claimed that, when taking into account emissions from feedstock, fuel production and delivery to the end user, transport greenhouse gases cumulatively account for 27% of total emissions.
Nonetheless, the motor vehicle is a consumer of fuel and contributor to the filthy air engulfing the world’s cities. This is why experimentation with various fuel sources is being undertaken by almost every major motor manufacturer – as well as specialist private companies and government-funded consortiums – with more vigour than ever before.
For example, in (broad) addition to normal petrol and diesel created by refining crude oil, there are also gaseous fuels (Liquefied Petroleum Gas and Compressed Natural Gas), biofuels (made from crops), synthetic fuels (oil from coal, such as that which SASOL produces), hydrogen (possibly the ideal option), and electricity (only really an option if its own production is clean).
Only hydrogen and electricity result in zero emissions from a vehicle, but hydrogen requires massive infrastructure to support it on a large scale, and the technology – especially in terms of batteries – for practical, full electric motoring is still some years away. It must also be remembered that whatever the fuel source, it needs to first be produced, and that goes back to the problem with industry.
Enter the hybrid!
The most immediate solution is undoubtedly the hybrid, which is the combination of a normal internal combustion engine with another supplementary motor.
Understandably, the word “hybrid” has a lot of mystique around it. Besides becoming the car of choice for Hollywood celebrities and politicians hell-bent on being perceived as responsible citizens, Joe Public doesn’t know too much about these machines.
Sure, he may understand that the end result of all the complex technology is a car which will save him money at the pumps, as well as delay an imminent and smoggy asphyxiation. His main notion of a hybrid will also undoubtedly be the Toyota Prius. But that’s about it.
Toyota was the first manufacturer to mass-produce a hybrid when it launched the first generation Prius in December 1997. In February this year, Toyota Motor Corporation (TMC – including luxury brand Lexus and commercial division Hino) passed the three million hybrid sales mark, and today Toyota offers a range of 16 hybrid vehicles in 80 countries.
The hybrid concept is nothing new, though. In 1901, while still in his mid-20s, Ferdinand Porsche developed the Lohner-Porsche Mixte Hybrid. The Mixte was the first hybrid vehicle – a series hybrid (explained in types and technologies) using wheel-hub motors mounted in each wheel, and powered by electricity delivered from batteries and a small generator. There were various hybrid projects in the early 20th Century, with many more through the ensuing decades.
The survey “Is the customer ready and willing to buy electric vehicles?”, conducted by automotive business intelligence company EurotaxGlass’s and UK-based marketing and research institute Harris Interactive (published in March this year), questioned over 5 000 consumers in France, Germany, Italy, Spain and the United Kingdom about their knowledge of, interest in, and intention to purchase an electric or hybrid vehicle.
The results showed 30% of respondents had an interest and, unsurprisingly, Toyota was the company with the highest brand awareness in this regard.
All things considered, then, it is little wonder that many more motor manufacturers have become serious about bringing hybrids to market and that the hybrid is also becoming more economical to produce.
Types and technologies
To better understand hybrids, one first needs to have a handle on the three basic levels of technology. The first is “soft” or “micro-hybrids” – these are not hybrids in the true sense of the word, but are vehicles that feature fuel-saving technologies such as stop/start functions, advanced aerodynamics, low rolling-resistance tyres and the like.
This is a more cost-effective solution to increasing a vehicle’s efficiency and most manufacturers do not label these vehicles as hybrids. Examples are BMW’s EfficientDynamics and Volkswagen’s BlueMotion vehicles.
Then there is the “mild” hybrid – which takes it a step further and has a normal internal combustion engine aided by a secondary electric motor. The latter fulfils a secondary role as it is only there to assist the internal combustion engine – which is constantly powering the vehicle. These “mild” hybrids constitute the majority of the hybrid market at the moment.
Finally, there is the vehicle that runs predominantly on electric propulsion – the “full” hybrid. When starting off the vehicle runs on electric power only, but as speed and load increases and/or as the battery’s reserve drops, the petrol engine is brought into action to assist. With a full hybrid, it is possible (though perhaps not practical) to drive around town on nothing but electric power.
There are also two basic types of hybrid power sources. The first is electric, which Lexus elegantly defines as the fusion of power from the internal combustion engine and an electric motor with a generator and high voltage battery pack. There are three types: parallel, series and power-split (or series-parallel) hybrids.
The differences between the three can be explained simply. In a parallel hybrid the engine and electric motor are connected to the transmission (hence the descriptor “parallel”) and can simultaneously transmit power to drive the wheels. These are therefore mild hybrids, as they cannot run on the electric motor alone. An example available on the South African market is the Honda Integrated Motor Assist (IMA) system.
A series hybrid throws in a bit of a curveball. Here, only the electric motor is responsible for powering the vehicle. Even though there is a small internal combustion engine (and transmission), this is used only to power a generator which charges the batteries and powers the electric motor when needed. Even though it might appear so, this system does not fall under the full hybrid banner as the internal combustion engine cannot power the car along. The much-publicised Chevrolet Volt is an example of a series hybrid. These are also known as range-extended electric vehicles (REEV).
The power-split/series-parallel hybrid presents the best of both series and parallel systems in one. Although set up as parallel hybrids, they incorporate power-split devices allowing for either the engine or electric motor (or both) to power the vehicle. This happens by “decoupling” the engine when it’s not needed. The best-known example of this system is Toyota’s Hybrid Synergy Drive used in all TMC’s hybrid products. These are true full hybrids.
The second type of hybrid power source is mechanical. This comprises a high-speed flywheel and continuously variable transmission (CVT) to collect, store and use kinetic energy. During braking, energy is recovered through the CVT and collected by the high-speed flywheel, which spins at up to 60 000 r/min, operating in a partial vacuum to minimise frictional losses.
When the driver pulls off again, the CVT transfers this energy back to the wheels. The energy is sufficient to power the car for short periods, and so these systems are perfectly suited for typical daily stop-start driving. This system would fall under the mild hybrid category, but is not very prevalent.
The British government-supported Flywheel Hybrid System for Premium Vehicles (FHSPV) programme, for example, claims its system delivers up to 60 kW
(80 hp) of recovered energy, and achieves an 11,9% improvement in consumption in the NEDC test cycle – conservative compared to claims by some other similar systems under development.
Mechanical hybrid systems are said to solve many of the challenges suffered by electric hybrids. Firstly, there is no inefficient conversion of energy from kinetic, to electrical, to chemical for storage, and then vice versa when needed to power the vehicle. Secondly, the costs, weight and packaging (typical mechanical hybrid systems weigh approximately
80 kg) as well as the recycling issues that batteries bring are also eliminated.
Here, there, everywhere
Since 1997 we have seen hybrid technology in everyday passenger vehicles, starting with the Toyota Prius. Today, we have small hatchbacks like the Honda Jazz Hybrid, diesel-hybrids such as the new Peugeot 508 RXH, luxury 4×4 vehicles including the Lexus RX 450h, and luxury executive saloons like the Porsche Panamera hybrid.
The hybrid version of Kia’s new third-generation Optima sedan set a Guinness World Record in September for the “lowest fuel consumption driving through all 48 contiguous U.S. states in a gasoline hybrid car”. The car covered 4 937 km (7 899 miles) through 48 states in 14 days, achieving an average fuel consumption of 3,64?l/100 km (64,55 US mpg).
Sports cars such as the Honda CR-Z and supercars like the Porsche 918 Spyder, earmarked for production in 2013, are also proving that green motoring needn’t be dull and boring.
Trucks and buses? Absolutely. Volvo, in particular, is one to watch at the moment, with its hybrid commercial vehicles claiming to be the world’s most efficient hybrid solution for buses and trucks. Volvo Buses has sold more than 250 hybrid units, these reducing fuel consumption and emissions by up to 35%. Volvo is also currently testing a prototype plug-in hybrid bus – essentially a hybrid with batteries that can be recharged at short stops to extend the time the vehicle runs without the diesel engine.
This is claimed to reduce energy consumption and emissions by a further 40%, making it 75% more efficient than the company’s current range of diesel-powered buses. It also represents a coming together of two alternative-drive technologies: the hybrid and the plug-in electric vehicle. This approach, known as a plug-in hybrid electric vehicle (PHEV), is an option that has not been widely explored before.
Volvo hybrid trucks are also proving their might. A modified Volvo VN (affectionately christened “Mean Green”) recently set three unofficial world speed records in the hands of one Boije Ovebrink at Hultsfred Airport in Sweden.
These are just a few examples of the proliferation of hybrid vehicles, and it would seem that the benefits far outweigh the drawbacks.
The real questions
But what are the drawbacks? How safe are the batteries? How long can the systems last and what are the costs of replacing failed components? Is the hybrid just a fad?
Most current hybrid vehicles use nickel-metal hydride (NiMH) batteries, as opposed to the previous environmentally-hazardous nickel-cadmium (NiCd or NiCad) variety. NiMH batteries present a good compromise in terms of current battery technology, can have exceptionally long lifecycles if managed properly, and the nickel can be recycled.
Lexus claims that its 288V NiMH battery has a normal use life expectancy of at least 10 years, and is covered by the vehicle’s warranty for four years/
100 000 km. Lexus also takes responsibility for the battery’s disposal at the end of its usable life. However, nickel-based batteries are known as carcinogens, although the actual effect they can have on human health is still the topic of much research.
In terms of safety, it must always be remembered that motor manufacturers spend huge sums of money on research and development, as well as safety testing, before releasing a new product onto the market. In passenger vehicles, the battery packs are designed to be contained within safety barriers and are protected (much like the fuel tank) by the car’s crash structure.
Obviously a different set of circumstances is presented in vehicles such as trucks, where the battery pack is somewhat exposed. As an example of safety design, however, Volvo recently performed a typical city crash test with its latest FE Hybrid truck. This vehicle’s battery pack weighs 578 kg (the battery itself weighing 232 kg) and operates at 600 volts.
In the simulation, a 1 600 kg car sled hit this side of the battery pack at a speed of 46 km/h during the 45 seconds that the battery is being charged – when the most current passes through the system. The safety system is designed to shut down all activity in the battery pack – which it did – and the battery pack proved stable, with no fires, fluid leaks or thermal energy being generated.
Unlike electric vehicles, where the batteries are generally leased to the consumer, batteries in hybrid vehicles are normally included in the purchase price. This, however, makes the initial price of the vehicle higher than that of an equivalent fuel-powered vehicle, as well as many soft hybrids.
Whether or not a hybrid makes economic sense depends on factors such as mileage and application, fluctuations in petrol prices, and whether government subsidies exist. In many countries, drivers of hybrid and other environmentally-friendly low-carbon vehicles receive tax cuts (on the vehicle), purchase discounts and free parking, for example.
In an effort to clear the fog shrouding the hybrid bandwagon, the American advocacy group, the Union of Concerned Scientists, developed its Hybrid Scorecard in 2005 to give US consumers a comprehensive comparison of hybrid vehicles available in their market. The most recent Scorecard, published in July 2011, evaluated 34 hybrids on factors such as the combined miles per gallon, environmental improvement score, hybrid value and forced features.
Amazingly, it was found that only 13 of the listed vehicles offered improvements of 25% in exhaust emissions when compared with their petrol-powered equivalents. In addition to under-delivering on promised fuel and environmental benefits, many manufacturers were also cited for placing too much emphasis on forced features that priced the vehicles out of reach of the average buyer.
Another problem is that the rare earth element dysprosium, used in producing many of the components in the motor and battery systems, is an extremely scarce resource and there are concerns of imminent shortages.
Exit the hybrid?
The hybrid is the most immediate solution to the global crisis of relentlessly increasing vehicle numbers, slowly dwindling resources, and an already polluted atmosphere which is wreaking havoc with our climate.
But it is only a short-term solution and the reality is that the motor industry will eventually have to move away from fossil fuels altogether. That doesn’t mean, however, that the hybrid will also become obsolete, as the technology is not limited to the internal combustion engine and can be combined with other alternative-drive technologies and fuel, like hydrogen.
In the immediate future, the internal combustion engine – petrol more so than diesel – is far from the end of its development. Modern engines are becoming more efficient and frugal by the day as new developments are incorporated into their design.
Average CO2 emissions in the EU fell 3,7% in 2010 to 140 g/km, after dropping 5,1% the year before. The 2015 target is 130 g/km and in 2020 it will reach 98 g/km (compare these to the average 1995 emissions figure of 186 g/km).
Admittedly, even the internal-combustion emissions target for 2020 does not match some of today’s full hybrids. The Toyota Prius, for example, already emits a meagre 89 g/km.
In terms of fuel consumption, however, many modern small-capacity petrol- and diesel-powered cars already have some of their hybrid counterparts licked. BMW’s new 2012 116d is claimed to consume 3,8 l/100 km (99 g/km of CO2), while the model it replaces returned claimed figures of 4,5 l/100 km and 118 g/km.
The Prius is claimed to deliver consumption of 3,9 l/100 km, while a more direct rival to the 116d – the new full hybrid Lexus CT 200h – claims 4,1 l/100 km (94 g/km).
Despite downsized engine capacities, these motors are also capable of producing power figures comparable to the much larger engines from only a few years ago. This is all thanks to advances in technologies such as turbo-/supercharging, high-pressure direct fuel injection, extremely high compression ratios, control over coupling and decoupling ancillaries (like the aircon compressor and water pump), improved breathing and thermal efficiency, and ever-powerful electronic control units.
It all combines to create a far more efficient, frugal, and powerful engine.
The report “Drive Green 2020: More Hope Than Reality” published in October 2010 by global research firm J.D. Power and Associates, estimated that by the end of that year, global hybrid (including battery electric vehicles) sales for the year would total 954 500 – a paltry 2,2% of the 44,7 million worldwide vehicle sales for the year.
Its estimation for the above figures in 2020 is 5,3 million hybrid sales; only 7,3% of the 70,9 million passenger vehicle sales predicted for that year.
So, while hybrid vehicle sales are expected to increase, it’s unlikely to become the overwhelming technology of choice for green motoring. It is expected that, as other alternative fuel technologies (particularly electric and hydrogen power) advance in their ease of manufacture, application and supporting infrastructure, these will become the more prevalant option.
Unfortunately, the benefits of the hybrid are being matched by other fuel- and emission-saving technologies. At the same time, the drawbacks – mainly the cost premium and perhaps blurred understanding of the technology – will continue preventing them from being a real option for most private buyers.
This article has only scratched the surface of the green-motoring debate, as the hybrid is just one of numerous options. In the short term it might be the best solution available, but with the projected 1,2-billion vehicles soon to be driving the world’s roads, hybrids cannot single-handedly save us from ourselves.