Lotus is a name you associate with sports cars from Norfolk. And in our eco-conscious times the light weight of the Elise et al makes Hethel’s cars an increasingly environmentally friendly proposition for the sporting driver. But what about the rest of us who need to transport a family of four, or can’t afford a lithe little Elise?
Lotus Engineering, the consultancy arm of Group Lotus, has teamed up with Continental to see if it can create a cost effective, fun to drive, but low CO2-emitting family car. To prove the system works it’s been fitted into the current shape Vauxhall Astra. Welcome then to the aptly but unimaginatively named Lotus Low CO2 car. CAR Online has been for an exclusive first ride.
Lotus Low CO2 car: the engine
The engine is a turbocharged 1.5-litre three-cylinder petrol of Lotus’s own design. The three-pot also features direct injection, variable cams using the same system as Porsche’s VarioCam Plus, and an integrated exhaust manifold that reduces weight by 20 percent and the part count by 35 percent.
There are also ‘smart’ coolant and fuel pumps that can reduce fuel consumption by up to two percent, and a mild hybrid system with stop/start. Better figures could be had with, say, a variable geometry turbocharger, but that increases cost so Lotus and Continental have sought a balance between headline stats and astronomical cost. That’s why the six-speed gearbox is lifted from a diesel Astra, rather than being bespoke.
Lotus Low CO2 car: the stats
The 15 percent CO2 reduction is claimed in comparison to a regular 1.8-litre Vauxhall Astra, so the test car produces 149 g/km CO2 versus 175.
What makes the figure even more impressive is that while the prototype has 158bhp and 177lb ft, the 1.8-litre makes do with a mere 138bhp and 129lb ft. In fact, the prototype was designed to match the performance of a 2.2-litre Astra. No 2.2 Astra exists, so Lotus and Continental simulated the car on computer.
Compared with the 1.8, Lotus’s car emits 15 percent less CO2, has 36 percent more torque, and 14 percent more power. Compared to the non-existent 2.2-litre, torque is up nine percent and power by three percent.
There’s no word on fuel consumption, but this car was designed solely to show how cheaply CO2 emissions could be reduced.
Lotus Low CO2 car: the ride
When the car starts up you get the typical direct injection gruffness. And quite a bit of noise too, as this prototype has no sound deadening whatsoever. That, combined with the smaller, lighter 1.5-litre engine makes the Low CO2 car fairly nippy. It feels more than on par with our long-term 168bhp Golf GT.
Charging around Lotus’s test track, four-up, it never feels slow. This is thanks in part to the mild hybrid system. The supercapacitors offer up an extra 74lb ft over short bursts to aid acceleration. The system isn’t designed to provide electric only running, but offer a boost in performance, and accommodate the stop/start function in traffic jams. Equipped with the mild hybrid system the 1.5-litre engine achieves 149 g/km CO2. Without it it’s 161.
The stop/start electronics are set up to be as aggressive as possible. In a BMW equipped with Efficient Dynamics technology the engine starts once you depress the clutch about 10 percent. Not in the Lotus. Fully depress the clutch, select a gear, and only when you’re literally at biting point does the engine restart. It takes a leap of faith to do, but the system shows how far you can go if you’re really serious about helping Mother Nature.
Lotus Low CO2 car: the future
Unfortunately Lotus and Continental missed their original 145g/km target, but are still hoping to get the car down to 140 g/km. Continental’s latest low rolling resistance tyres will be the next step, and then other technologies like tyre pressure monitors and gearshift indicators will hopefully reduce the emissions further. And as the system is petrol, there’s no need to worry about diesel’s NOx emissions.
It’s easy to be blasé about the Low CO2 car, especially when a BMW 118i emits only 140g/km. But the Lotus offers so much more performance, and compared to with 174g/km Golf GT, betters it in every on-paper figure. Price-wise the two should be roughly equivalent. All Lotus and Continental need now is a buyer for the technology. Vauxhall?