Daimler showcased two dozen clean and efficient new cars in Seville, Spain, last week. Here are some models Christopher Tan drove or rode in.

Smart fortwo Electric Drive

This zero-emission runabout (right) is ideal for congested cities. Its electric motor is powered by a natrium-nickel battery that can run for 115km between recharging (via domestic wall socket).

It is very quiet, torquey and offers great pick-up. Being gearless, it is smooth and seamless.

41hp motor; 0-100kmh in 5.7secs; 112kmh; 12kWh/100km

Smart fortwo mhd (micro hybrid drive)

Crawling in the highly built-up city, this car is able to be in Eco mode frequently. In this mode, the stop-start system cuts off the engine. It also does this when the car is at the traffic lights. The three-cylinder petrol engine starts up again when the brakes are released. In such a tiny car, the stop-start is rather jerky. The car is not as torquey as the all-electric Smart, but is still very usable in urban settings.

999cc; 71hp; 92Nm; 0-100kmh in 13.3secs; 145kmh; 4.3 litres/100km

Mercedes-Benz B170 NGT BlueEfficiency

This purpose-built bi-fuel Merc suffers none of the shortcomings of petrol cars converted to run on natural gas. No power loss, no space sacrifice, no ridiculously short range. Over a 195km drive at speeds ranging from 140-160kmh, only half the car's 16kg of gas was used up. It does not have as much pulling power as diesels, so you often have to shift down to overtake.

2,034cc; 116hp; 0-100kmh in 12.4secs (5-speed manual tested); 184kmh; 7.3 litres/100km

Mercedes-Benz F700

This is a research car that is the size of an S-class but is powered by a 1.8-litre four-cylinder turbo petrol engine assisted by a hybrid module.

Called the Diesotto engine, it is supposed to have the best characteristics of both petrol and diesel engines.

It features high-pressure direct injection, variable compression ratio and a laser-guided adaptive suspension system. It also uses thin low-resistance tyres and a very streamlined body to further lower fuel consumption.

At low speeds, the engine runs on extremely high compression and the fuel combusts without spark plugs (like a diesel). But when the pace picks up, the engine switches to a lower compression ratio and the sparks come on.

Daimler does not reveal fully how this works, but says it has to do with a special crankshaft arrangement.

The car has the power of a normally aspirated 3.5-litre V6 but the economy of a turbodiesel. It meets Euro 6 emission standards, producing only 127g of carbon dioxide per km.

Its cabin is exceptional, with cork-lined panels, rear seats that can be configured to face each other, a sushi bar as well as an on-board 'avatar' who acts as your co-driver.

We could only ride in the car. It appears a bit gruff for an S-class (Daimler explained that its exhaust system was not built to cope with the new engine), but is otherwise quite comfortable.

Its Pre-Scan suspension system cuts out roll in corners and allows the car to go over speed humps with impunity. But it fails to detect tiny surface imperfections just before the humps.

1,800cc; 258hp (including electric motor); 400Nm; 0-100kmh in 7.5secs; 200kmh (electronically limited); 5.3 litres/100km

Mercedes-Benz F600 HYGenius

This driveable fuel-cell concept vehicle (above) incorporates several new technologies that will be finding their way into production models. These include a 700-bar hydrogen storage tank that allows the car to store enough gas to exceed 400km. Its fuel-cell stack is compact and able to operate at minus 25 deg C.

It employs a lithium-ion battery for power storage. This forms the basis for the fuel-cell B-class that will be launched in 2010, although the F600 is rear-wheel-driven (the only RWD fuel-cell car).

Life! managed to sneak a drive in this off-limit prototype and found it to be very quiet and very powerful at speeds up to 120kmh. It handles like a well-sorted RWD car. Like an electric car, it has push-button drive selection.

115hp motor; 350Nm; 170kmh top speed

Mercedes-Benz A170 BlueEfficiency

Blue Efficiency is Mercedes-speak for cars with a host of economy-enhancing features such as stop-start function, low-resistance tyres and a belt-driven starter-generator. The car is perky like current A-classes, but drivers will find comfort in the fact that it will save fuel in jams and at the lights. But its air-con compressor also shuts down when the engine is off, so it may not be so popular in Singapore.

1,699cc; 116hp; 155Nm; 0-100kmh in 10.9secs (5-speed manual tested); 188kmh; 6.5 litres/100km

This article was first published in The Straits Times on 22 June, 2008