Ricardo, QinetiQ and PSA Peugeot Citroën Reveal Efficient-C Low-Carbon Diesel-Electric Parallel Hybrid
|Architecture of the Efficient-C. Click to enlarge.|
Ricardo, QinetiQ and PSA Peugeot Citroën today presented the results of their Efficient-C two-year collaborative research project: a parallel hybrid-electric diesel demonstrator vehicle emitting just 99 g/km CO2 (equivalent to 3.75 liters per 100km or more than 63 mpg US) based on a fully featured Citroën Berlingo Multispace family car.
This represents an improvement of 30% in fuel economy and concomitant reductions in carbon dioxide emissions when compared to the equivalent diesel production vehicle. The same diesel hybrid powertrain fitted in a C-segment 5-door sedan would also only emit 90g tank-to-wheel CO2.
The Efficient-C was one of five proposals selected to participate in the UK Department for Transport’s Ultra Low Carbon Car Challenge. The UK Government launched the Ultra Low Carbon Challenge on 29 April 2003 and invited proposals from individual companies and consortia to demonstrate the feasibility of a family sized ultra-low carbon car in the UK. The five winning proposals, which included the Efficient-C project, were announced on 15 October 2003.
Ricardo was the project leader and contributed program management and hybrid vehicle systems; PSA Peugeot Citroën provided the base vehicle and expertise in vehicle architecture; and QinetiQ contributed expertise in the areas of energy storage, battery management and high voltage wiring systems. The company also provided prototype energy storage and management hardware to support the demonstrator vehicle.
The Euro-IV compliant Efficient-C demonstrator comprises the following integrated technologies:
A PSA Peugeot Citroën 92 hp (69 kW), 215 Nm, 1.6 liter HDi, turbo-charged and inter-cooled common rail diesel engine.
A compact 23kW, 288V DC electric motor mounted between the engine and the transmission, providing up to 130Nm electrical torque assist, efficient electrical power generation, regenerative braking and full electric vehicle (zero emissions) operation at low speed. The clutch is mounted between the engine and the motor, allowing the engine to be disconnected from the rest of the drivetrain in order to provide an all-electric mode where only the electric motor propels the vehicle.
A 5-speed automated manual transmission delivering cost-effective automatic functionality.
A 288-volt, 2 kWh Lithium-Ion battery pack and battery management system to monitor state-of-charge, cell temperature, and cell voltage balance.
The engine is started by a 12V starter-alternator. Other supporting systems include a low-temperature cooling circuit to protect the electric motor and power electronics, an electro-hydraulic power assisted steering system, electrically powered air conditioning and a touch-screen driver display.
Advanced supervisory control system based on the Ricardo rCube prototype controller to co-ordinate the many vehicle systems to meet driver demands whilst optimizing fuel economy.
The diesel hybrid offers six operating modes:
Mode 1. The Internal Combustion Engine drives through the clutch and gearbox to the wheels—i.e., conventional vehicle mode, used on the highway.
Mode 2. The motor absorbs torque from engine, generates electrical energy. This forces the engine to operate more efficiently, and stores energy in battery for later use.
Mode 3. The motor draws power from battery and provides additional torque to wheels to boost acceleration.
Mode 4. Electric drive using stored electrical energy. The motor is used for pull-away and low load operation.
Mode 5. Regenerative braking. The engine is off, and the vehicle’s kinetic energy is captured by the motor and stored in the battery.
Mode 6. Battery charging with vehicle stationary, allowing long term use of electrical equipment such as air conditioning.
|Efficient-C vs. Berlingo|
|Berlingo 1.6 HDi||Efficient-C||Benefit|
|Fuel consumption (urban) l/100km||6.7||3.7||45%|
|Fuel consumption (hwy) l/100km||4.7||4.0||15%|
|fuel consumption (comb.) l/100km||5.4||3.75||30%|
|Max speed (mph)||99||106|
|0-62 mph (sec)||14.8||13.4|
We are delighted with the results from this research project which demonstrates the potential for a step change in CO2 emissions reduction with a diesel parallel hybrid. The challenge now is for the motor industry and its suppliers to achieve the cost reductions required for the mass production of diesel hybrids to be considered.—Alain Klein, Director of Hybrid Vehicles Development at PSA Peugeot Citroën
The team estimates that the current additional cost for the hybrid powertrain would be approximately £3,000 ($US5,600) over the cost of a conventional diesel vehicle.
The other projects selected in 2003 were the MG Rover Group working on a four-wheel drive IC engine-electric hybrid powertrain; ZyteK Automotive working with a diesel plug-in series-hybrid architecture (earlier post); Bertrand UK working on a hybrid powertrain with a contra-rotating flywheel energy storage; and Artemis Intelligent Power, working on a hydraulic hybrid powertrain.