Greg Kable
2 February 2012

What is it?

We’ve been hearing a lot about cylinder deactivation recently. And not surprisingly given the tough emission standards car makers are being forced to adhere to in an effort to meet upcoming EU6 regulations set to come into force in September 2014.

However, most of it has been reserved for larger petrol engines such as Audi’s excellent new twin-turbocharged 4.0-litre V8, as offered in the in the A8 and soon to become available in the Bentley Continental GT.

But in a move that proves such technology also has a place in smaller engines, Volkswagen has unveiled a heavily reworked version of its widely used turbocharged 1.4-litre four-cylinder petrol powerplant running an innovative valve system developed in partnership with Audi.

The system is capable of shutting down the middle two cylinders on light throttle loads, effectively turning it into a 700cm3 twin for lower consumption and emissions, particularly in city driving and highway running at constant speeds.

The new unit, of which only the 82mm cylinder bore spacing is shared with the older EA111 engine it replaces, forms part of Volkswagen’s new modular EA211 engine range that is set to begin rolling out throughout various Volkswagen models bound for the UK in the not-too-distant future, including the Polo driven here in prototype form.

Among the more significant changes over the existing turbocharged 1.4-litre four cylinder TSI engine is a smaller 74.5mm bore and longer 80.0mm stroke – something that suggests there will also be larger capacity variants of the EA211, too. The compression ratio has also risen.

What’s it like?

With 138bhp and 184lb ft of torque at 1500rpm – some 34bhp and 55lb ft more than the existing Polo 1.2 TSI, the four-valve-per-cylinder engine provides the Polo 1.4 ACT with spritely off-the-line qualities, a satisfyingly flexible in-gear character and, thanks to long gearing, a relaxed cruising nature.

Nothing is official just yet, but expect on a 0-62mph time around 8.0sec and top speed around 125mph for seven-speed DSG (dual shift gearbox) equipped versions like that tested. Creditable performance, then.

However, it is the engine’s ability to seamlessly switch from four to two cylinder operation that impresses the most. It takes a steady application of throttle at engine speeds above 1250rpm to make the transition, but when it does the only hint two cylinders have been deactivated is an advisory in the instrument panel and slightly raw exhaust note – something Volkswagen’s development engineers say will be altered before production begins. There’s no loss of momentum, as the revs are immediately matched to take into account the lower capacity.

Ease into the throttle gently and it is immediately obvious there is less power on tap in two-cylinder mode. But at city speeds and at a constant cruise it does not hinder progress. Push beyond 4000rpm and it automatically switches back into four-cylinder mode, instantly providing the full level of performance.

Volkswagen denies the deactivation of the middle two cylinders could lead to a potentially disastrous cooling of middle section of the aluminium block engine, saying the internal water and oil system has been conceived to heat the middle two cylinders even when they are shut down.

Should I buy one?

The Polo fitted with ACT technology is still at the prototype stage, but it’s clear that the new cylinder deactivation system brings lower consumption and emissions without spoiling performance or the potential for fun.

Overall, the new system is claimed to bring a claimed 0.4 litres per 100km reduction in consumption and 8g/km lowering of CO2 emissions – figures that are likely to see the upcoming Polo 1.4 TSI ACT come close to matching its 1.6 TDI sibling for overall economy and efficiency.

Volkswagen Polo 1.4 TSI ACT (prototype)

Price: TBC; Top speed: 125mph (est); 0-62mph: 8.0sec (est); Economy: TBC; Co2: TBC; Kerbweight: TBC; Engine type, cc: 4 cylinder, inline, 1390cc; Power: 138bhp at 4500-6000rpm; Torque: 184lb ft at 1500-4000rpm; Gearbox: seven-speed DSG

Join the debate

Comments
19

Re: Volkswagen Polo 1.4 TSI ACT

2 years 38 weeks ago

I think I'd take the GTI instead.

Re: Volkswagen Polo 1.4 TSI ACT

2 years 38 weeks ago

It doesn't say so, but I presume this is the same engine tested in the A1 Sportback a couple of weeks ago?

Re: Volkswagen Polo 1.4 TSI ACT

2 years 38 weeks ago

Not the headline story I know but why does a powerful, torquey engine in a small light car possibly need seven forward gears?

  • Let depreciation be your friend...

Re: Volkswagen Polo 1.4 TSI ACT

2 years 38 weeks ago

catnip wrote:

It doesn't say so, but I presume this is the same engine tested in the A1 Sportback a couple of weeks ago?

I believe it is, yes.

Re: Volkswagen Polo 1.4 TSI ACT

2 years 38 weeks ago

Perhaps I'm being a bit sceptical, but I have that niggling feeling that this bit of tech may be good for the carefully controlled EU cycle results but of little benefit to the motorist in the real world where things are far less exact.

The 7-speed DSG happens to be in the VW parts bin, which is no doubt why it will be used. Their 6-speed one is heavier and meant for torques over 184lb/ft so would be OTT for this application.

Re: Volkswagen Polo 1.4 TSI ACT

2 years 37 weeks ago

Adrian987 wrote:
Perhaps I'm being a bit sceptical, but I have that niggling feeling that this bit of tech may be good for the carefully controlled EU cycle results but of little benefit to the motorist in the real world where things are far less exact.

Sadly, I think you are right.

Question.

Forgetting the "environmental" element to the argument at the moment and looking at the real world where us, the average motorist, is more concerned about cost, there are a couple of things I want to know.

How much is this car likely to cost?

How much is it likely to save the motorist in fuel over, say, 12,000 miles?

How much is it going to cost to service and repair (no I'm not being a Luddite but this ain't a simple engine and gearbox combo!)?

Then consider how much would it cost us, including initial purchase cost, road fund etc, if this engine was say a little less efficient, a lot simpler, potentially a lot more reliable to run over the same 12,000 miles?

I'd wager the simpler car would be cheaper.

 

 

It's all about the twisties........

Re: Volkswagen Polo 1.4 TSI ACT

2 years 37 weeks ago

My maths isn't great but please bear with and advise if I'm wrong <?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />Their claim (probably optimistic) is a saving of 0.4litres every 100km. Say £0.50 every 60 miles, £8.33 saved every 1,000 miles, £83.00 every 10,000 or say a year for this type of car meaning after 3 years of ownership you've saved £249.00.

You've got a more complicated car, with a lot less power at times, that cost more to produce that you've ultimately paid for.

Looks to me like you could actually be worse off

 

Hydrogen cars just went POP

Re: Volkswagen Polo 1.4 TSI ACT

2 years 37 weeks ago

^ what you say is entirely plausible but it is a prototype. Once a prototype improves and makes it to mass manufacturing where the price comes down and the savings increase it should then actually make sense.

Re: Volkswagen Polo 1.4 TSI ACT

2 years 37 weeks ago

Complicated tech or not - I want one; the first petrol engine I've seen that might tempt me away from a torquey turbodiesel in ages. 138 bhp, 184 lb ft with 1.6 TDi like consumption but decent performance - fabulous. And I'll trust the German engineering excellence to make sure the deactivation system and the DSG work properly and cooperate to make it fun.

Yes please

Re: Volkswagen Polo 1.4 TSI ACT

2 years 37 weeks ago

It is a pity that VW are adding this to a complex 1.4 turbo.

I would like to see it an ordinary 16 v 1.8 or 2.0 petrrol as an alterantive to a complex small displacement turbo

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