Micro-hybrid vehicles remain relatively unexplored in the automotive sector, but their time in the limelight may soon be due.
More sophisticated than vehicles with simple start-stop systems, but less reliant on electric power than a mild hybrid vehicle, micro-hybrids are nevertheless a low-hanging fruit, potentially selling five million units by 2018.
As Earthtechling writes, it's all about the batteries.
Stop-start systems are perhaps the easiest fuel-saving systems to implement in a modern car, requiring little more than a beefed-up starter motor to ensure the car can handle the thousands of extra stop and start cycles it will experience over its working life.
By contrast, mild hybrids--such as Honda's 'Integrated Motor Assist', or GM's eAssist, make use of an electric motor for mild assistance and regeneration, backed up by a larger nickel or lithium battery pack.
Micro-hybrids fit somewhere between the two. There's no need for an electric motor, but a more robust battery is required for the extra stop-start cycles, and to keep useful features like air conditioning running where a stop-start-equipped car may not.
The benefits are potentially great, if not on a car-per-car basis then on a wider scale, since the technology can be applied so widely.
Fuel economy can be boosted by 3-10 percent, and potentially more. At those amounts, you'd not see your fuel bills slashed overnight, but when applied to tens, or hundreds of thousands of vehicles, the overall saving is huge.
In the U.S. alone, micro-hybrid sales could jump from 300,000 this year to 5 million by 2018. In Europe, that figure could top 12 million. Even 3 percent fuel savings over 5-12 million vehicles equates to a vast reduction in oil use.
With the right technology--such as the supercapacitors used for energy capture in Mazda's i-ELOOP system, savings could be even greater.
Power generated under braking rapidly charges the supercapacitor, which then powers auxiliary items--reducing load on the car's engine, saving fuel. Mazda claims a five percent improvement for that alone.
The latest lead-carbon (PbC) batteries are also ideal for micro-hybrid applications, as they're stable and don't decline as quickly as lead-acid units. Like lead-acid batteries though, they're highly recyclable.
The other big benefit is cost. A better battery and light energy capture devices cost a great deal less than a mild hybrid system.
The effects are even less intrusive--perhaps suitable for vehicles where a more traditional driving experience is required, or simply for customers who aren't keen on the nuances of hybrid technology. Yet they're ideal for busy cities like New York City--where regular stop-and-go traffic impacts upon gas mileage.
Hybrids, plug-in hybrids and more will still offer greater fuel savings--but as a means of improving existing vehicles for little extra cost, micro-hybrids could be the way forward.