All breakthrough technologies open a new world of further potential benefits, which are usually not fully exploited in the first generation, in order to minimize industrial risk.
The Common Rail technology, a Fiat worldwide premiere in 1997, paved the way to more than a decade of further technological evolutions such as “Multijet” for multiple injections, Small Diesel Engines and the very recent Modular Injection technology, soon to be launched on the market.
Similarly, the Multiair technology, a Fiat worldwide premiere in 2009, will pave the way to a wave of further technological evolutions for gasoline engines:
- Integration of the Multiair Direct air mass control with Direct gasoline Injection to further improve transient response and fuel economy.
- Introduction of more advanced multiple valve opening strategies to further reduce emissions.
- Innovative engine-Turbocharger matching to control trapped air mass through combination of optimum boost pressure and valve opening strategies.
While electronic gasoline fuel injection developed in the 70’s and Common Rail developed in the 90’s were fuel specific breakthrough technologies, the Multiair Electronic Valve Control technology can be applied to all internal combustion engines whatever fuel they burn.
Multiair, initially developed for Spark Ignition engines burning light fuel ranging from gasoline to Natural Gas and hydrogen, has wide potential also for Diesel engine emissions reduction.
Intrinsic NOx reduction of up to 60% can be obtained by internal Exhaust Gas Recirculation (iEGR) realized with intake valves reopening during the exhaust stroke, while optimal valve control strategies during cold start and warm-up bring up to 40% HC and CO reduction of emissions. Further substantial reduction comes from the more efficient management and regeneration of the Diesel Particulate Filter and NOx Storage Catalyst, thanks to the highly dynamic air mass flow control during transient engine operation.
Diesel engine performance improvement is similar to that of the gasoline engine and is based on the same physical principles. Instead, fuel consumption benefits are limited to few percentage points because of the low pumping losses of Diesel engines, one of the reasons of their superior fuel economy.
In the future, powertrain technical evolution might benefit from a progressive unification of gasoline and Diesel engines architectures.
A Multiair engine cylinder head can be therefore conceived and developed, where both combustion systems can be fully optimized without compromises. Moreover the Multiair electro-hydraulic actuator is physically the same, with minor machining differences, while internal subcomponents are all carry over from the Fire and SGE applications.
