NEW ENGINES: BETTER PERFORMANCE, LESS EMISSIONS!
From Engine to wheels
Future innovations in the pipeline will increase vehicle efficiency without affecting performances; on the contrary…
We are probably accustomed to thinking that vehicles nowadays largely depend on electronics leaving very little room for "iron", that is, mechanical parts.
The truth, as always, lies somewhere in the middle and assigns – of course, one might say - important roles to both elements. Electronics has proportionally registered the greatest progress, allowing to create, among other things, power steering, where the steering wheel is not mechanically connected to the steering box, or fuel injection systems able to perform multiple fuel injections for each combustion cycle.
Electronics has enabled the use of new sophisticated mechanical solutions, in turn, the result of great developments in the field of engineering and materials.
This synergy is completed by yet another element, the network and its connectivity, which has produced, and continues to do so, significant progress in the field of energy efficiency.
In trying to outline the evolutionary paths of engineering we must start right from here, the contribution that a connection to the Network can make in reducing fuel consumption.
The idea is to use GPS and connectivity to save as much energy as possible through a number of set parameters that take into account what happens while driving.
Connecting to the web to reduce fuel consumption
The concept is not new and finds application on vehicles already on the market: knowing that a downhill is approaching, for example, will prompt a reduction in the oil and water flow rate as well as the alternator’s work rate, since the descent will reduce the engine’s work rate, lightening therefore the accelerator pedal.
This system will further evolve in the case of hybrid powertrains considering their energy recovery systems, rather than being limited to mere fuel and energy saving.
As an example: according to AVL, an Austrian automotive research and consulting company, for a vehicle powered by a 80 kW electric motor, a 30 kW range extender could be enough if the vehicle was equipped with a system able to anticipate the conditions of the road ahead, taking into account traffic, the route, traffic lights, level crossings and the like.
It could be said that a connected powertrain may affect the mechanics of the vehicle, influencing the choice of a range extender.
A simulation made by AVL in city traffic showed how a strategy of this type could stretch the mileage of the same electric vehicle from 70 to 120 km.
The same obviously applies also to hybrid vehicles that, upon detecting a descending road ahead, would use the battery more, sparing the engine, knowing that it will be recharged during the descent.
The effort of cleaning
An interesting aspect of the constant evolution of engines is that the burden of reaching the challenging target for CO2 emissions to be achieved by 2020 rests entirely on combustion engines: the European Union has set at 95 grams / km average emission, the U.S. 140 g, Japan 105 g and China 117. The paradox is quite evident and stems from the fact that the spread of hybrid and electric cars will be quite slow and their contribution limited; therefore, combustion engines and powertrains will have to develop quickly to meet the legal requirements.
A variable compression ratio could represent a future solution, for example by adopting special connecting rods with an eccentric pin bore, so as to vary the distance between crankshaft and piston.
Gearboxes will also be important: FEV (company that has partnered with BMW for the hybrid i8) presented a dual-clutch 10 gears transmission system that , with the help of an electric motor, reduces moving parts (with only four synchronizers) making gear shifting smoother.
This unit is only 37 cm long and manages torques of up to 400 Newton / meters and a power output of 200 kilowatts.
Large improvements will come from the adoption, for new engines, of high compression ratios, variable valve timing, alternative cycles (for example, Miller or Atkinson), and liquid cooled EGR systems (exhaust gas recirculation).
The potential of these measures was proved through a demo car developed by AVL and based on a Volkswagen: the engine, modified to work with the Miller cycle, liquid cooled EGR and exhaust systems as well as high compression ratio, produced only 92 g / km of CO2!
Other improvements will result from the reduction of internal friction, from the recovery of heat dispersion and solutions to reach the operating temperatures faster.
Combining performance with fuel efficiency
Even diesel engines will “have their say”: a group formed by AVL, Hyundai, Valeo and East Penn (a producer of batteries), is developing a unit that combines a 1.7-liter turbo-diesel engine which is joined by a second electrically powered compressor; everything is integrated with a special 14 kW alternator / starter and a special 48 volt lead-carbon battery pack, special - and long lasting - lead batteries with negative plates consisting of carbon electrodes.
The resulting unit could be qualified as a mild hybrid enhanced by an electric compressor and a special battery pack, which offers several advantages over both lithium and conventional lead elements.
The system can propel the vehicle for short distances in pure electric mode, while the electric compressor, with its immediate response, compensates the turbo lag of the turbocharger. The 48 Volt electrical system maximizes the recovery of braking energy.
The combination of these technologies guarantees an increased power output of 25% decreasing, at the same time, the consumption by 20%.
It seems that the role of the electric compressors will be increasingly important even for hi-performance engines: a Volvo 4-cylinder 2-liter prototype engine, equipped with two turbo-chargers and a 48-volt battery pack, develops 450 hp and 500 Nm of torque, while still meeting Euro 6 standards and employing materials compatible with normal production series, since the strains remain within the limits of today's engines. Among other technological innovations, a special mention goes to a very high pressure fuel injection system - 250 bar – achieved through a double Denso pump.
Since these monster performances also stem from the ideal use of fuel energy as well as a meticulous reduction of internal friction, consumption is also much lower than those of any other engine with the same power.
In short, it seems that with these new engines you can have a lot of fun fully respecting your eco-friendly conscience!