Lotus Engineering, the automotive consultancy division of Lotus, and Continental Division Powertrain have presented the results of their “Low CO2” research collaboration. The Low CO2 vehicle concept is being proposed as a practical option for manufacturers to reduce their fleet average CO2 emissions.

2008 Lotus Low CO2 Concept
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The Low CO2 vehicle concept is demonstrated in an Opel Astra and uses a Lotus Engineering designed pressure-charged three-cylinder 1.5-litre gasoline engine integrated with a number of Lotus and Continental technologies. It features an innovative integrated exhaust manifold design, centrally-mounted injectors, cam profile switching for lift and timing, a high pressure fuel pump, and a mild hybrid drive.

The Low CO2 Astra produces a g/km CO2 reduction of 15% against the naturally aspirated 1.8 litre 4 cylinder engine version of the same vehicle. While forging comparisons to the most frugal B-segment cars, the Low CO2 Astra – on the NEDC (New European Driving Cycle) – produces performance figures that are comparable to market leading C-segment cars with larger engines.

2008 Lotus Low CO2 Concept
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The primary objective of the Low CO2 project was to deliver greatly reduced CO2 emissions while maintaining an engaging driving experience from an affordable set of technologies. The solution employs a cleverly integrated set of powertrain systems within a downsized overall package.

Technical details after the jump.

Technical details

Technical specification of the Low CO2 engine when installed in Opel Astra:

  • Cylinders: 3
  • Displacement: 1.5 litres
  • Bore: 88mm
  • Stroke: 82mm
  • Compression ratio: 10.2:1
  • Fuel pump pressure: 200bar
  • Emissions (NEDC): 149 g/km CO2 meeting Euro 5 Emission standards
  • Max power: 160ps @ 5000rpm
  • Max torque: 240Nm @ 2500rpm - 4000rpm
  • Mild hybrid motor output: 12kW
  • Mild hybrid energy storage system: 60v supercapacitors

Key features of the Low CO2 engine in detail:

CPS switching tappets:

Lotus Engineering’s Cam Profile Switching system incorporates lobed tappets that vary valve lift
and timing. The system is produced under licence by INA and features in Porsche products in
its ‘VarioCam Plus’ system.

High pressure fuel pump:

Continental Division Powertrain’s single cylinder fuel pump driven directly from the tri lobe cam
on the exhaust camshaft.

Fuel injectors:

Affordable, 200bar, solenoid, DI centrally mounted injectors by Continental Division Powertrain.
Smart Coolant Pump and Demand Regulated Intank Fuel Pump: Continental Division Powertrain’s electric water and fuel pumps could save up to 2% of fuel.

Mild Hybrid Drive:

The Continental Division Powertrain system features unique water cooled motor housing to
match transmission to engine block.

Integrated Exhaust Manifold:

Lotus Engineering designed and developed a new advanced cylinder head design featuring an
integrated exhaust manifold. The production-ready technology can significantly reduce manufacturing costs, emissions and weight on most gasoline-engined passenger vehicles. An integrated exhaust manifold has potential to:

  • Reduced parts count: 35% fewer components resulting in lower inventory, production, logistics and aftermarket costs
  • Weight reduction: total system mass reduction of 20% resulting from elimination of separate exhaust manifold
  • Improved engine durability


The Low CO2 project exploits the findings of the HOTFIRE project, a previous research programme led by Lotus Engineering and also including Siemens VDO, Loughborough University and University College London. HOTFIRE, which started in October 2004, was based at Loughborough University to explore a permanent homogeneous charge direct injection strategy through the use of centrally-mounted injectors.

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