Peugeot - Citroen Develop Diesel-Electric Hybrid System

With over seven million of its world-famous HDi diesel engines under its belt, PSA-Peugeot-Citroen is considered the foremost authority on diesel technology,

Published: 06-Feb-2006

In terms of green, fuel-efficient automobiles, there are three schools of thought: gasoline-electric hybrids, modern direct-injection diesel and hydrogen (either fuel cell or internal combustion). Though its nearly impossible to get a hold on any sort of hydrogen-powered automobile currently due to their high cost, extremely limited production and nearly non-existent refueling infrastructure, the other two are easy to access. Hybrid vehicles are sought after for their ability to provide zero emissions when running on pure electricity and improved fuel economy on the road, while diesels are chosen for their general thriftiness and plentiful torque; but what about the two together?

Following in the footsteps of Volkswagens diesel-electric Mk.IV Golf test bed vehicle, which the German automaker unveiled at last years Michelin Bibendum clean-energy challenge, Frances largest automaker has decided to have a go at playing with electricity. With over seven million of its world-famous HDi diesel engines under its belt, PSA-Peugeot-Citroën is considered the foremost authority on diesel technology, and has jumped onto the hybrid scene with two demonstrator vehicles powered by their new Hybride diesel-electric hybrid system, which they will be showing for the first time at this years Geneva Motor Show.

Like the VW Golf, the Honda Accord or the Ford Escape hybrids, the very French-sounding Hybride system has been integrated into vehicles currently in production; each brand will show its own version starting with the futuristic-looking Citroën C4 Hybride and the Peugeot 307 Hybride, both of which compete in the mainstream family-sized hatchback (Golf, Caliber, Civic etc.). Bar the vivid green Hybride vinyl sticker livery that each concept wears, both the C4 and 307 are plain, stock production vehicles that do not differ from their mass-produced counterparts. Not much is different on the inside either, but for the console-mounted LCD display which shows the cars power flow, as with the Escape or Prius.

The Hybride system works much like any current gasoline-electric hybrid, pairing an internal combustion engine, in this case a 1.6-liter HDi common rail turbodiesel featuring a pollutant-capturing particulate filter system, with a 23 kW (31-hp) electric motor that can be used to generate or produce electric power. The diesel motor features PSAs Start and Stop system, which automatically turns the engine off when idling and restarts it instantly when the gas pedal is pressed - just like other hybrids. Electrical power is stored in a high-capacity lithium-ion battery pack. Because the Hybride system utilizes an electronically-controlled manual gearbox with sequential-shift, the car can be operated using any combination of diesel and/or electric power, making it a full hybrid, as opposed to a mild, combination hybrid that merely assists the combustion engine.

By backpacking electricity to the already efficient HDi diesel powerplant, the Hybride system improves substantially upon the performance of current gasoline electric hybrids. For example, both the C4 and 307 Hybride are able to return a truly impressive 69 mpg on a mix of city and highway driving, while returning a mere 90 grams (3.17 ounces) of CO2 per kilometer (0.62 miles) driven. For comparison, a Peugeot 307 3-door HDi mated to a 5-speed manual, the same vehicle sans the Hybride system, is capable of 48 mpg on the mixed cycle, and produces 129 grams (4.55 ounces) of CO2 per kilometer (0.62 miles) driven, yet is 35 percent more powerful due to the boost of the electric motor. PSA claims that the Hybride-equipped C4 and 307 are capable of besting an equivalently sized gasoline-electric hybrid by some 25 percent.

Like most manufacturers, the only thing that is stopping PSA from giving the Hybride system the green light at the show is the impact of the expensive electrical components on the price tag. While hybrid technology may be viable for high-end sedans, large SUVs and purpose-built green machines, the price gap between a Hybride-equipped 307 or C4 is twice as large as consumers would be willing to spend. PSA has pledged to lower the cost of technology in order to implement wide-spread hybrid availability to the masses, and expects to have a solution presented before 2010. In four years time, the world should have an instinctively different outlook, and by then, perhaps diesel-hybrid technology will be more widespread.


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Mercedes-Benz confirmed that it will introduce five diesel models beginning this fall. Honda, BMW, Nissan and the Chrysler group each confirmed plans to add diesels to their lineups over the next three to four years. Photo: Mercedes E-320 BlueTec diesel.

Engineering breakthroughs and cleaner fuel give diesel engines a second chance. Photo of Audi A8 Quattro TDI.


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