Sunday, 10 July 2016
Are powertrains facing transition?
Could diesel engines be on their way out? asks Ricardo Plc in its latest quarterly journal, RQ.Ricardo points to the PSA Group’s investment to double production of three-cylinder gasoline engines while developing plug-in hybrids and electric power trains for its new dedicated architecture for battery vehicles.
Gasoline engine capacity at the groups Trnava plant in Slovakia however is being expanded with the Douvrin plant in France manufacturing electric drivetrains in-house.
Although PSA Group's new ‘Push to Pass’ strategic plan calls for continued diesel development, the main focus, in the eyes of Ricardo, seems to be on gasoline and hybrid drivetrains.
Push to Pass programme calls for seven plug-in hybrids between 2019 and 2021 on the medium EMP platform, as well as four EV (electric vehicle) models from 2021 onwards built on the CMP city platform.
But Ricardo, eyeing new 48V systems coming on stream, "believes that 48V hybrids may well contribute more to emissions reductions in the next five to 15 years than all plug-in vehicles combined".
Ricardo is itself one of a consortium formed to develop 48V through-the-road hybrid vehicle technology. Here Ricardo is in bed with project leader Control Power Technologies, Provector and Tata Motors European Technical Centre at Warwick University.
Ricardo has responsibility for design and analysis of an integrated 48V rear exile module for a B-segment city car with the two-year project itself aiming for a 15 per cent reduction in CO2.
However, Ricardo observes that Volkswagen has just unveiled a new generation of small gasoline engines – 1.5-litre EA211 TSI evo – which operates on the Miller cycle with a compression ratio of 12.5 to 1. Using a variable geometry turbocharger, selective cylinder deactivation and a common rail system injecting fuel at 350 bar through new 6mm injectors, the engine develops between 130 and 148 bhp with a claimed 10 per cent better fuel consumption than the outgoing 1.4-litre TSI.
But, in the same issue, Ricardo notes that "super-diesels" are fighting back, pointing to new engines from Audi, BMW and Daimler.
Audi's 4-litre V8 in the SQ7 SUV, with a compacted graphite iron (CGI) vee block, develops 435 bhp and 900 Nm torque from injection pressures of 2,500 bar.
BMW's 3-litre I6 engine fitted to the 750d is the most powerful engine in the company's history with an output of 400 bhp and 760 Nm torque, but uses no less than four turbochargers. Again the injection pressure is over 2,500 bar.
Finally, Daimler's new OM 654 four-cylinder modular diesel engines complies with 2017 European emission regulations. The initial four-cylinder 2-litre engine develops 195 bhp.
On a bhp/litre basis, the performance of these three “super diesel” engines varies widely. They have figures of: 109, 133 and 98 respectively!