Honda's next Accord will launch a new and ultra-clean range of diesel engines that could be capable of over 60mpg and, it claims, will be as clean as a petrol engine; these are the first scoop shots of it.The new clean diesel engine is based on the current 2.2 i-CTDi. A European-market Accord fitted with a sophisticated version of the 2.2 diesel, and capable of 62.8mpg, was recently shown at a diesel technology convention in California. The new engines will enable Honda to sell diesels in the US, which has recently introduced tough new emissions rules. They will use a catalytic converter that reduces nitrogen oxide output by converting it to ammonia, and then use the ammonia to further neutralise the remaining NOx. The diesels will replace Honda’s US-market Accord V6 hybrid, which has not been a success. The cars in our pictures are the next US-market Accord coupe and saloon, which launch in America this September, the latter of which as the Acura TSX. The coupe's exterior is influenced by the look of the Coupé concept from January’s Detroit motor show; the darker saloon (see gallery) is likely to be a faithful match for the next UK-market Accord.