Firm hesitates over whether to use three- or four-cylinder units in next-gen engines
14 December 2009

Mercedes bosses are poised to decide whether the firm’s next-generation of downsized engines will be three- or four-cylinder units, according to a senior company source.

The new engines – sized between 1.4- and 1.6-litres will be used in both the next-generation A/B-class replacement and the C-class range.

Although BMW has already committed itself to using a thee-cylinder engine in the next-generation 3-series, Mercedes bosses are hesitating to follow because of what they say are the extra costs and complexity involved.

One senior source told Autocar that using a three-cylinder engine (most likely engineered as half of Mercedes V6 unit) "was relatively expensive to optimise".

This means that extra, potentially costly, measures had to be employed with the to reduce the noise, vibration and harshness that is typical of a three-pot layout.

As well as extra sound deadening, more sophisticated engine mounts and selective stiffening for the bodyshell would all be needed, adding to the costs of what would be entry-level models for the brand.

According to the source, the cheaper alternative is for Mercedes to look for a partner who could supply a more conventional four-cylinder unit, which Mercedes could then modify with its own direct injection and turbocharger.

Hilton Holloway

Twitter - follow autocar.co.ukSee all the latest Mercedes reviews, news and video

Our Verdict

Mercedes-Benz C-Class 2007-2014

The Mercedes C-Class marks a return to the company's old-school values of all-round quality and maturity

Join the debate

Comments
7

14 December 2009

Merc men at Stuttgart, Here is one suggestion: renew your licence for Wankel rotary engine (remember C111 ??), and team up with Mazda R&D to come up with efficient and yet mighty powerful rotary power plant. No NVH, no balancer shafts, no unecessary extra weights. Your market and Mazda's are completely different so this cooperation would not hurt anybody.

14 December 2009

[quote MikeFoxtrot]Your market and Mazda's are completely different so this cooperation would not hurt anybody.[/quote]

Apart from Merc who are looking for a cheap and efficient powerplant for their entry level models. A Wankel Rotary is not going to provide the fuel consumption required and also doesn't not give high torque characterstics that merc seem to be angling after (direct injection, turbocharged). On top of that having to pour half a litre of oil in everytime you fill up...

14 December 2009

[quote theonlydt]A Wankel Rotary is not going to provide the fuel consumption required and also doesn't not give high torque characterstics that merc seem to be angling after (direct injection, turbocharged). On top of that having to pour half a litre of oil in everytime you fill up...[/quote]

Is this because the development hasn't kept pace with other engines over the years?

Would be interesting to see what could actually be done with the rotary engine and some decent development money.

 

 

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

14 December 2009

[quote TegTypeR]

Is this because the development hasn't kept pace with other engines over the years?

Would be interesting to see what could actually be done with the rotary engine and some decent development money

[/quote]

Mazda have been continually developing the rotary engine. I think it's a great design, with limited application. The rx-8 engine is sooooo smooth, but ultimately has very little torque and so you have to rev the nuts off it which gives appalling fuel economy. I do wonder if there's anything they can do about the oil consumption. At least they seem to have sorted out the problem of the rotor tips wearing.

14 December 2009

[quote TegTypeR]Would be interesting to see what could actually be done with the rotary engine and some decent development money.[/quote]

There are other types of rotary engines which might be more effective if enough money was spent on development.

The only 3-cylinder I have driven is a VW one (in a Seat) and I had to look very carefully before deciding it was safe to put petrol in the tank.

14 December 2009

The 3 cylinder engines i have experienced have varied hugely. The engine in a 107 is very enthusiastic, but not smooth enough for a Merc. The original Insight was better, but used the electric motor to pulce in between strokes to smooth out the power delivery. Very clever, but not much use for Mercedes as i doubt they will be offing a hybrid any time soon at this end of the market.

However the 3 cylinder engines in the Polo and Fabia are nasty, especially the diesel. Maybe its because they are bigger, but what ever the reason, a 4 cylinder car would be a better bet than end up with something like that.

14 December 2009

I always thought that engines configured in multiples of 3 cylinders were the optimum for smoothness in an engine?

Add your comment

Log in or register to post comments

Find an Autocar car review

Driven this week

  • Citroën C3 Aircross
    First Drive
    17 October 2017
    It's got funky looks and a charming interior, but it's another small SUV, and another dynamic miss. Numb steering is just one thing keeping it from class best
  • Skoda-Karoq 2.0 TDI 4x4
    First Drive
    16 October 2017
    Diesel version of Skoda’s junior SUV is unobtrusive and undemanding, but we’d still go for the silkier petrol version of the Karoq
  • Audi Q7 e-tron
    First Drive
    16 October 2017
    Expensive and flawed but this understated diesel-electric Audi Q7 has a lot to offer
  • Citroën C3
    First Drive
    16 October 2017
    Is the third gen Citroën C3 ‘fresh and different’ enough to take on its supermini rivals? We spend six months with one to find out
  • BMW X3
    First Drive
    15 October 2017
    A satisfying rework of the X3 that usefully improves its handling, cabin finish, space and connectivity to make this BMW a class front-runner again