As covered by The Motor Report back on 16 October, tightening global exhaust emissions are bringing to a halt the trend of decreasing engine sizes.
With an eye on Europe’s 2019 real world driving emissions tests (RDE) - part of the Worldwide Harmonized Light-duty Vehicles Testing Procedure ( WLTP) - Volkswagen chairman Herbert Dies has told a meeting of European media: “The trend of downsizing is over – emissions tend to go up as engines get smaller.”
This is a significant development from the company which launched its Up! compact car with a three-cylinder engine and currently offers the Polo hatchback for sale in Australia powered by a 1.2-litre four-cylinder engine. And of course Volkswagen is currently embroiled in the so-called ‘dieselgate’ scandal which centres on differences between exhaust emissions as measured in real world driving versus testing procedures.
Volkswagen says while that 1.0-litre three-cylinder engine will continue in the Up! (withdrawn from sale in Australia) and some international Polo models, no smaller petrol engines are under development and the current 1.6-litre diesel will be as small as that engine family will go.
Further, with diesel fuel tipped to become more expensive (in order to optimize its performance in the RDE tests), analysts predict its popularity with new car buyers will dive.
It may be future generations of the Volkswagen Polo will not run diesel engines at all (although the all-new model due for launch this year will include diesel-fueled models).
New exhaust testing procedures in North America – to reflect real world driving - have seen numbers 40 per-cent higher than those achieved according to current test standard. In China, were traffic snarls see vehicles sitting idle for much of the time, real world exhaust emissions data is even further removed from that obtained in laboratory tests.
Germany’s autobahns prove challenging for brands like Volkswagen - Mr Diess says a vehicle needs at least 100kW of power to reach 200km/h (whereas the current laboratory exhaust emissions tests are based on only 10kW of output). So a non-turbo three-cylinder engine just won’t cut-it with new car buyers in Germany (or the rest of the world in reality).
Back in October, The Motor Report detailed European media reports confirming Volkswagen, General Motors and Renault will be increasing the size of their engines to nullify the high exhaust emissions of small three and four-cylinder powerplants.
The reports pointed-out the considerable heat soak of small engines where turbochargers are used to deliver the sort of performance demanded by new car buyers. To tackle that heat, vehicle manufacturers inject more fuel which in-turn causes extra exhaust emissions – specifically unburnt hydrocarbons, carbon monoxide and fine particles.
“The techniques we’ve used to reduce engine capacities will no longer allow us to meet emissions standards,” Renault-Nissan powertrain chief Alain Raposo said. “We’re reaching the limits of downsizing.”
The analysis by Reuters is proving to be spot-on as it stated Volkswagen’s 1.4-litre diesel, GM’s 1.2-litre diesel and two engines from Renault – a 1.6-litre diesel and a 0.9-litre petrol – are headed for the scrapheap. Looks like Volkswagen will move first.
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MORE News & Reviews: Volkswagen | Engines | Emissions