Controlled Power Technologies and Advanced Lead-Acid Battery Consortium to unveil LC Super Hybrid at Geneva show; low-cost “micro-mild” demonstrator
|The LC Super Hybrid demonstrator. Click to enlarge.|
The LC Super Hybrid, conceived by Controlled Power Technologies (CPT) and the Advanced Lead-Acid Battery Consortium (ALABC) to show that significant CO2 reduction can be achieved through electric hybridization at low voltages (12-48 volts) using the latest lead-carbon batteries, will make its world debut at the Geneva Motor Show. The applied micro-mild hybrid technology builds on previous work by CPT carried out with AVL, which built the LC Super Hybrid and handled the systems integration. The demonstrator further develops AVL’s efficient low carbon ELC concept (earlier post).
The production-ready technology offers the potential of a mass-market, gasoline-fueled family car with drivability, performance and 5.6 liters/100 km (42 mpg US) fuel consumption achieved at lower cost than an equivalent diesel model. The low-voltage technology enables aggressive, near-term down-sizing and down-speeding of existing engine families, the partners say.
|The demonstrator features a Valeo electric supercharger. Click to enlarge.|
The LC Super Hybrid delivers CO2 emissions of less than 130g/km compared with 140 g/km for the baseline Passat 1.4-liter TSI and an even more significant reduction when compared with 160 g/km for the 1.8-liter TSI model. This represents a reduction in CO2 emissions of 8 and 23% respectively.
The low voltage (12V) “micro-mild” technology demonstrator includes a production-ready electric supercharger recently sold by CPT to the leading French tier 1 supplier Valeo (earlier post). Other international companies involved are powertrain developer and systems integrator AVL Schrick based in Austria and Germany, springy materials specialist Mubea also from Germany, and Provector, a leading expert in battery management systems, based in the UK.
|CPT SpeedStart stop-start technology. Click to enlarge.|
The demonstrator is based on a series production 1.4-liter turbocharged VW Passat TSI model. Technologies include an electric supercharger; next generation belt-integrated starter generator with an advanced belt tensioning system; carbon enhanced valve regulated lead–acid (VRLA) batteries which avoid the need for supercapacitors, and higher gear ratios to reduce engine speed.
Recalibration of the engine increases power from 120 hp to 140 hp (89 kW to 104 kW) and torque from 200 to 275 N·m (148 to 203 lb-ft). This power and torque is more comparable with VW’s larger 1.8-liter TSI gasoline engine, which delivers 158 hp and 250 N·m; the engine output of the LC Super Hybrid is generally equivalent to vehicles in the 2-liter class. Despite the enhanced gasoline engine performance the vehicle achieves near diesel levels of fuel economy, but with lower production costs.
|Advanced lead-acid battery system. Click to enlarge.|
In 6th gear, which is taller even than the gearing in the baseline vehicle, the 80 to 120 km/h (50 to 75 mph) top gear acceleration is reduced by 3.5 seconds from 16.0 to 12.5 seconds. Similarly, the 0-100 km/h (0-62 mph) time is reduced by 2.5 seconds from 11.1 to 8.7 seconds compared with the 1.4-liter TSI and achieves virtually the same acceleration (8.5 seconds) as the 1.8-liter TSI model.
The LC Super Hybrid incorporates CPT’s next-generation SpeedStart stop-start system, which includes intelligent torque and current control with enhanced stop-start capabilities. The SpeedStart system is an advanced belt-integrated starter generator (B-ISG) operating at 12 volts, and the first and only system based on the highly controllable switched reluctance motor-generator technology.
Low voltage switched reluctance (SR) motor-generators are not currently employed by the automotive industry in mass production. The motors are of simple, robust construction using steel, aluminium and copper and avoid the use of increasingly expensive rare earth materials required for permanent magnet motors. The SR technology is licensed from Nidec Corporation of Japan, one of the world’s leading suppliers of electric motors.
The Mubea belt tensioner system facilitates rapid reversals of the motor-generator and virtually halves the belt loads, reducing friction of the front end accessory drive system while significantly improving belt durability.
The carbon-enhanced lead–acid battery design (supplied by Exide Technologies) helps to maximize energy recuperation (regenerative braking) during deceleration, supporting SpeedStart’s potential for high power generation, torque smoothing and electrical energy recovery.
The improved lead-carbon battery design employed in the LC Super Hybrid allows for a strong charge and discharge characteristic, while the carbon-enhanced negative plate formulations significantly improve life under hybrid vehicle duty cycles. Further battery life improvements have been achieved via attention to battery management. These next-generation lead-acid batteries are already under test in pre-production vehicles.
The demonstrator adds about 79 kg to the curb weight of the baseline vehicle. However, much of this additional mass including the test equipment would be eliminated in a production vehicle as well as the existing starter motor, which is made redundant by the belt-integrated starter generator.
When designed for 48V, the low-voltage LC Super Hybrid is expected to deliver more than the nominal 25% improvement in CO2 emissions and fuel economy already achieved when compared with typical 2-liter naturally aspirated sedans, and will more than match their performance and drivability, the partners said.
The additional cost to the vehicle manufacturer is estimated between €750 and €1,500 (US$1,000 to $2,000).
We are confident we have met the challenge facing the automotive industry for cost efficient CO2 reduction technology, compatible with legislative demands and at showroom prices that consumers are willing and able to afford. There is no huge upfront cost with this technology and therefore no need for expensive subsidies from the taxpayer.—Allan Cooper, European projects coordinator at ALABC
Cooper will present technical details of the LC Super Hybrid at the 5th International Advanced Mobility Forum (IAMF), a scientific and public meeting focused on future vehicle technologies, which draws together motor industry engineers and scientific experts. The annual forum is held in collaboration with Bern University of Applied Sciences, the Swiss association e’mobile, and other organisations. The event is supported by the world body for automotive engineering FISITA.