PSA first results of real-world fuel consumption show levels of up to 50% higher image

The first fuel figures of Peugeot-Citroen real-world condition tests have arrived and there are evidently higher than in the laboratory.

After the emissions storm triggered by Volkswagen, Peugeot-Citroen announced that it would measure and publicize real-world fuel economy figures for their models. Now, the French automaker has released the initial results of its tests for three models. The measurements were made public under a protocol developed with the NGO Transport & Environment, on public roads near Paris – 25.5 km urban, 39.7 km extra-urban, and 31.1 km motorway – with passenger and luggage on board, on different road gradients, and with the air-conditioning system turned on.

Based on the European Union’s Real Driving Emissions (RDE) project, the protocol measures fuel consumption by means of a portable emissions measurement system (PEMS) installed on the vehicle. Bureau Veritas, an independent and internationally body, has guaranteed the protocol, ensuring that it is conducted in line with specifications and that the results are accurate and reliable. The company also made a survey – conducted by an independent body – among its customers to compare the final results.

The models tested were the Peugeot 308 1.6l BlueHDi 120 S&S M6 “Allure”, Citroen Grand Picasso 1.6l BlueHDi 120 S&S M6 “Exclusive” and Citroen DS3 1,6l BlueHDi 120 S&S M6 “So Chic”.

The consumption measured under the protocol were 5,0 l/100 km for the Peugeot model (official combined: 3,2 l/100km), 5,6 l/100 km for Grand Picasso (official combined: 3,8 l/100km) and 4,9 l/100 km for DS3 (official combined: 3,6 l/100km). Consumption measured via customer surveys: 5.0-5.1 l/100km at Peugeot 308, Grand Picasso with 5.5-5.7 l/100km and 5.1-5.3 l/100km for DS3.

PSA says it will release before summer official real-world fuel consumption figures for 30 Peugeot, Citroen and core DS models.

  • Pavel Cervinka

    There is NOTHING like objective “real-world condition consumption” figure. It will always depend mostly on the driving style, then on other conditions like temperature, air pressure, dampness, particular fuel (additives, higher or lower contents of water, ethanol, light/heavy oils contents), tyres pressure, tyres model, tyres wear, wheels tracking, weight distribution in car (two heavy passengers on front seats vs. one light driver and heavy luggage in the rear boot), dry vs. very wet road (water on road adds resistance), suspension/shocks fine tuning setup & wear, traffic, use of electric gadgets like a/c, blower, radio, lights, wipers, seat heating, seat ventilation, massage seats, media entertainment, satnav, also oil engine (phase of service interval – is it a new or old oil, which type in particular), oil in gearbox, oil in differentials, etc. etc. etc. etc. etc. etc. etc….

    The REALLY objective figures could be:
    – engine thermal efficiency 3D graph (x=rpm, y=%throttle, z=%efficiency)
    – car CDx (air resistance)
    – car’s rolling resistance (depends on wheel size & pressure and on car’s weight, and a bit on road surface)
    – gear ratios – which predefines the rpms for any speed in a particular gear, which then can be correlated to the engine thermal efficiency
    – “actual” consumption at specific speed, with zero gradient, on particular tyres, tyre pressure, air pressure and air temperature and specific cargo weight (incl. passengers and fuel) and its dristribution (front/rear)
    – optimal speed for highest gear and minimal consumption (use to be around 60-80km/h, or 40-60mph), two figures – the speed, and the consumption at that speed (as per previous point – zero gradient, particular tyres, pressures, temperatures, cargo weight)

    The first one is very difficult to get as it’s part of the industrial secret; the CDx is (must) be officially released with the car, gear ratios are USUALLY also easy to find out but without the thermal efficiancy 3D graph they are quite useless, but can at least be correlated to power/torque graphs, as generally the best thermal efficiency is around the torque peak and 60-80% power – but that’s a rarely high power regime, so there use to be another near-optimum at about 20% throttle slightly under (or above) torque peak, ie Honda Insight engine is tuned to have two thermal optimums, one for “low power” run (used at constant mesh/motorway cruising), and one for “higher power” mode (ie overtaking / accelerating)…

    Conclusion: all this “real world consumption” is just one very big bubble of P-R bol*ocks…