Expert answer

Hi John, 

The Atkinson engine is a type of engine invented by James Atkinson in 1882. The Atkinson Cycle is where the stroke of the piston can very in length across the four cycles in a four-stroke internal combustion engine. The length of the stroke during the power cycle is increased to promote efficiency, but because this comes at the expense of a shorter intake stroke there is some loss of power and therefore this engine design is best suited for use in hybrid systems where the electric motor can make up for some of the loss of power. 

In conventional four-cycle petrol engines, fuel enrichment is sometimes necessary to cool the exhaust gases, preventing degradation or destruction of the catalytic converters. In an Atkinson cycle engine, compression and expansion are not symmetrical, and the valves close late, delaying compression. This creates a high expansion ratio for less compression, reducing intake and exhaust energy losses and converting combustion energy to engine power more effectively. As a result, the exhaust temperature is lower than that of conventional engines.

The current model Toyota Prius Hybrid uses a 1.8-litre Atkinson Cycle engine. Adopting the Atkinson cycle and a cooled exhaust gas recirculation system brings significant gains in fuel efficiency and emissions reduction.

Prius 1.8-litre Atkinson Cycle engine

Because the intake valves close late in an Atkinson cycle engine, compression is delayed. This creates a high expansion ratio for less compression, reducing intake and exhaust energy losses and converting combustion energy to engine power more effectively. As a result the exhaust temperature is lower than that of conventional engines. Cooled Exhaust Gas Recirculation reintroduces the cooled gas into the intake system, further reducing engine operating temperatures.

Other models to use Atkinson Cycle engines include the Lexus CT200h, Lexus RX 450h, Mercedes S400 Blue Hybrid

Expert answer

Hi Andrew,

According to Ciaran Allen, Sales Manager of Mercedes-Benz, "Stop/start is the main factor in reducing CO₂ and is available now on manual models. We are not expecting full availability on stop/start including seven-speed auto until August production - September arrival. Because of our market seasonality August and September are not big production months for us, so while it will be available we really consider E-Class seven-speed as a 2012 car. The model price won't be reduced but the auto road tax will go from band C to band B."

Hope that answers your question?

Expert answer

Hi Joe,

Yes there is a difference, but it has nothing to do with the fact that one of them is imported from the UK. The 2007 Porsche 911 Turbo is taxed on the old system, which is scaled according to engine size. As its engine is larger than 3,000cc the annual tax is €1,566.

As the 2009 model was registered after the 2008 changeover to CO₂-emissions based taxation, and its emissions are higher than 226g/km, it is considered to be in the highest group, Band G. That attracts a significantly more expensive €2,100 annual bill.

Hope that helps

Expert answer

Hi Gerry,

As the Peugeot 508 is brand new there is no way to gauge how reliable it will be. Its predecessor, the 407 saloon, suffered from relatively minor niggles all its life, but first impressions suggest the 508 is of higher quality. The Passat CC, though sold in smaller numbers than the four-door saloon version, has an exemplary reliability record.

In terms of fuel economy and emissions, the 2.0-litre HDi versions of the Peugeot 508 saloon with a manual gearbox emit 125g/km (Band B) and use 4.8 litres/100km (58.9mpg) on the combined cycle. The 1.6-litre HDi models are more efficient, though slower obviously.

In comparison, the VW Passat CC 2.0 TDI (with a manual gearbox again) uses 4.7 litres/100km (60.1mpg) and emits the same 125g/km, so there's virtually nothing to choose between them.

Hope that helps.

Expert answer

Hi Ciaran,

Thank you for your query. The Kia pro_cee'd is a good car, but thankfully the only thing negative about it is the silly name. We really rate the car and it would make a great second-hand buy. It has been a while since we drove a pro_cee'd so we called Kia Ireland to get a reminder on the engines. We were told that very few 1.4-litre petrol models were sold in 2008 and practically none in 2009 after the road tax laws based on emissions were introduced.

The first thing to note then is that the petrol models are scarce, but quite a bit cheaper than the diesels. A petrol model will cost you €9,945 while a diesel from the same year could cost you €12,950 - more than €2,000 more. You certainly won't save €2,000 in fuel and road tax in a hurry, so it depends on how long you intend to keep your car. If you change your car quite often and residual values are a concern then you probably need to get the diesel, but if you will be keeping the car for a long time then you should get the petrol, especially given the relatively low mileage that you do.

In terms of what to look out for, there is nothing. There have been no recalls that we know of and the car has few real faults apart from the fact that visbility isn't great out of the small rear window, but then you can expect that with any coupé-like hatchback.

Anyway, I hope this helps and doesn't actually make it more confusing! If there is anything else don't hesitate to come back to us.

Expert answer

Hi John, 

According to Hyundai, "The 2.0 CRDi automatic features an all-new six-speed self-shifting transmission that is smaller and lighter than any other six-speed automatic offered anywhere in world.

As well as the obvious economy and emissions benefits, the system uses a uniquely-shaped torque converter to reduce its overall size, and features three planetary gears and four pinion differentials.

Although it offers smooth and precise gearshifts throughout the rev range in fully auto mode, the gearbox can also be used like a sequential six-speed manual. A gate-type shift pattern allows the driver to choose between fully automatic or clutchless manual ‘Sport’ modes, which offers even more driver involvement and a more rewarding driving experience beyond the city limits."

I hope this helps.

Expert answer

Hi Jim,

The combined economy figure for that car is about 50mpg (5.6 litres/100km) and it has CO₂ emissions of 149g/km. I would say that this would be a better buy than a 2005 Passat Estate because there will probably be less wrong with it and it will be easier to put right if it has a few issues. The Passat of that year wasn't VW's finest work, so I'd plump for the Avensis. The usual rules apply in terms of proper history checks.

Hope that helps.

Expert answer

Hi Ronan,

We asked Ciaran Lowe, a former service manager for Nissan Ireland, to answer this one. He told us. "I can understand your reasoning for removing the Diesel Particulate Filter (DPF) because of the excessive cost of replacement. However, the DPF on diesel vehicles plays an important roll in reducing vehicle emissions. In fact these filters can reduce diesel soot emissions by up to 80 percent, so by removing the DPF it is interfering with the emissions on your vehicle. By re-mapping the ECU it is only tricking the engine management  system to see emissions within spec regarding the DPF system. However even with the ECM re-mapped the vehicle will still fail any future emissions tests. The fact your light is on indicates the system has identified out of range emissions."

I'm afraid the best solution all-round is to seek a used DPF filter.

We've talked to a few people in the industry and short of messing with the actual lights in the dashboard there is no way around this. We can't recommend this route, but it could be done by any auto electrician.

Expert answer

Hi Mairead,

I guess it depends on how bad your Ibiza is. You will generally get a better deal as a cash buyer, but it will also probably cost you money to get rid of your Ibiza if you bring it to a scrap yard. Sadly you don't qualify for scrappage. but there are lots of good offers around, especially from the likes of Renault, who will give you a great scrappage price on a car eight years old or over. You could have any Renault Mégane within your budget. We recently drove the GT Line version of the Mégane and it looks great with tons of equipment including a built in TomTom navigation system. 

The Mazda3 diesel is €19,995 and you get air conditioning, Bluetooth, cruise control and alloy wheels as standard and it is a cracker of a car. I think given your budget that this would be an excellent choice. It has low emissions too, so annual road tax is just €104. 

Feel free to come back to us if any of these suggestions don't work. 

Expert answer

Hi Noel,

Two new models have been launched in the Skoda Yeti range and these make up part of a strong model line-up for 2011, which will include a new 4.9 per cent finance offering on Yeti models. Skoda, as part of the Volkswagen Group, will offer finance through its own bank.

The two new models in the Skoda Yeti range are a 1.6-litre TDI Greenline that has 105hp and replaces the 2.0-litre 100hp diesel. It has emissions of 119g/km, which means it sits in motor tax band A.

The car features stop-start technology, low-rolling resistance tyres and brake energy recuperation. Prices start at €23,165 for the Greenline Active, €24,125 for the Ambition model and €26,035 for the Experience.

Also on offer for the first time is the 4x4 version. It comes with a 2.0-litre diesel engine putting out 170hp and with emissions of 155g/km it sits in motor tax band C.

There are Ambition and Experience specifications available for this model and prices are €29,545 for the Ambition and €31,480 for the Experience.

Skoda sold 775,000 cars worldwide in 2010, but has ambitions to sell 1.5 million by 2015. It will launch several new models to the line-up between now and then.

A small A-segment car that will take on the Ford Ka and Toyota iQ will go on sale in 2013, followed by a replacement to the Skoda Octavia that same year. A new version of the Skoda Roomster comes in 2014 and that same year a new version of the Fabia will arrive.

The new Yeti models are now in dealerships. 

Hope that helps