A five-seater family car, with full luggage space, capable of more than 70 mpg (or less than 4 litres per 100 km) yet this car will go from 0-60 mph in 12 seconds and looks and drives quite normally. And there’s more. Emissions are half the Euro 4 standard and will meet legislation up until at least 2010. Sounds too good to be true, doesn’t it? Anthony Lewis reports.

The closest I’ve been able to come to write anything like that recently was when I had a Honda Insight parked in the drive. Only two seats and little luggage space and the neighbours gathering in clusters. Toyota Prius comes closer to real-life motoring, but people still point and stare. Next year, Honda will launch its Civic Hybrid. Looks normal, rather good in fact, but since we haven’t driven it yet, let’s reserve judgement.

Taking the whole diesel-electric hybrid argument further forward is a project called i-MoGen, a joint venture between Ricardo of the UK and Valeo of France. This was announced a year ago at the Frankfurt motor show. The i-MoGen vehicle an Opel Astra has been doing the grand tour of vehicle manufacturers since the end of June and this month (October) heads to Japan.

The motor industry previews involved 23 vehicle manufacturers and other key organisations throughout Europe and North America.  More than 600 ride and drive appraisals have been given to chief executives, vehicle and powertrain vice-presidents, programme managers and technical specialists. In between, journalists were let loose for a day well,  a 20-mile drive and given an update on the project.

The i-MoGen uses what is known as a ‘mild hybrid’ which is defined as being when the electric motor provides 10 per cent or less of the maximum engine power; as distinct from ‘full’ hybrids when the electric motor typically provides around 40 per cent of the maximum engine power. Ricardo and Valeo are, with some justification, upbeat about the development so far.

Ricardo technology director, Neville Jackson said: “We have successfully shown the right people how

“i-MoGen delivers significantly improved fuel economy without compromising vehicle performance “

i-MoGen delivers significantly improved fuel economy without compromising vehicle performance and have received very positive feedback.  We have also shown that the technology is affordable with a ‘cost-to-fuel-economy-benefit’ ratio similar to that of a diesel compared with a gasoline engine.”

Michel Lifermann, transversal vehicle projects director for group R&D at Valeo, said: “The real challenge for the industry is achieving excellent fuel economy at the same time as meeting all anticipated future emissions legislation. That alone is difficult enough, but the industry also has to achieve this without concessions to vehicle performance and refinement as well as maintaining the ability to seat four adults comfortably, otherwise it’s simply a non-starter for the average motorist.”

The driving force for hybrids is the stark fact that the easier part of meeting emissions legislation has been done. Since 1995, the industry has reduced emissions by an average of 1.9 per cent a year to reach the 165 g/km target. To meet the 140 g/km fleet average target for 2008 will require annual average reductions of 2.1 per cent – and that requires new technology, said Nick Owen, manager  of the Technology Department at Ricardo Consulting Engineers in Shoreham. Ricardo is forecasting a hybrid market penetration of 6 per cent by 2010, from 0.15 per cent last year.

How does i-MoGen work?  A downsized four cylinder 1.2 litre diesel engine (just the block remains intact from the original Isuzu/Opel unit) developing 74 kW is linked to a 42 volt system that includes an integrated starter-alternator, an advanced battery management system and intelligent engine cooling and HVAC system. The downsized engine has 20 per cent less fuel consumption compared with a 2.0 litre conventional diesel engine and offers possible weight savings of up to 30 per cent which offsets the additional weight normally associated with mild hybridisation.

The integrated starter-alternator (ISA) is the system that enables the downsized diesel engine to perform in similar fashion to larger, heavier engines. It has three key functions. The first is automatic start-stop which cuts off the engine when at standstill and restarts it as soon as first gear is engaged. Those with long memories will recall Volkswagen fitting stop-start to a diesel Golf. It never took off, maybe because we weren’t ready for it; maybe because we didn’t trust it to start when we were at the head of the queue at traffic lights. A short drive in the i-MoGen and stop-start almost felt natural. Stop-start means silence at traffic lights and zero emissions.

Secondly, the ISA acts as a torque booster, giving the 1.2 litre diesel the same sort of mid-range performance that you would expect from a 2.0 litre unit. The test car is fitted with a device that allows the torque boost to be turned on and off, so you really can tell the difference.

The final role for the ISA is to provide regenerative braking which means that as soon as the driver lifts off the throttle, a signal is sent to the ISA which immediately converts the vehicle’s kinetic energy to electrical energy that can be stored in the battery. A Ricardo-developed controller ensures that all the systems work optimally together towards any given target. If more torque is required a choice can be made between using the electrical device or the diesel engine the optimum solution will depend on other factors such as electrical loads and the state of battery charge.

Valeo-developed 42-volt water pumps, fans and heat exchangers take the concept a stage further. They are belt-less and clever cooling of the engine brings further economy benefits, says Valeo’s Lifermann. The package also takes engine management to a whole new level. By making sure the right bits work together at the right time, Ricardo and Valeo claim a further 5 per cent improvement in economy. In all the i-MoGen represent an improvement of 28 per cent over the diesel engine base vehicle. Twenty per cent of that comes from downsizing, fast warm-up and intelligent cooling; three per cent from the stop-go and five per cent from regenerative braking.

But what about the cost the Achilles heel of so much new technology I hear you ask? Taking an MPI gasoline engine as the base, today’s hybrid (gasoline with DC Permanent Magnet motor) costs about 190 per cent more and achieves about a 32 per cent improvement in CO2 emissions. The i-MoGen costs about 170 per cent more and achieves almost a 50 per cent improvement in C02 emissions. If this is the medium-term future of family motoring, then the sooner it arrives the better, not just for the planet’s dwindling natural resources, but also for the hard-pressed European motorists especially in the UK paying the highest pump prices in the world.