Although there have been diesel Hondas in the past, the engines have been sourced from other companies.
When Honda last had a diesel Accord, from 1996 to 1998, the unit was built by Rover Group at Solihull, and the current diesel Civic uses a reworked Isuzu engine.
However, far from merely dabbling, Honda is now ready to take diesel very seriously. A new 2.2-litre engine has been designed from scratch using a new manufacturing method and will become available in the Accord in January 2004 before going into the CR-V sports utility vehicle later in the year.
As it is late to the game, Honda's new engine could not afford to be any worse than the best of the current crop of modern diesels.
Therefore, it uses second-generation common rail injection and will be compliant with Euro IV emissions standards from its launch, ensuring company car drivers can avoid the 3% benefit-in-kind tax surcharge.
In the Accord, the engine will produce 138bhp and 251lb-ft of torque and Honda's own figures show it achieves 52.3mpg on the combined cycle with carbon dioxide emissions of 143g/km.
The figures put it right at the top of the upper-medium sector for fuel economy and carbon dioxide emissions.
Honda hopes that as well as some substitution of petrol Accord sales, the majority of drivers of the diesel Accord will have swapped from rival vehicles.
Honda splits the upper-medium sector into three areas. In the 'mass market' segment there are cars such as the Ford Mondeo, Vauxhall Vectra, Renault Laguna and Volkswagen Passat. At the top of the sector there is the 'premium' segment with the likes of the Mercedes-Benz C-class, BMW 3-series, Jaguar X-type and Audi A4. In the middle there is the 'quality' segment where Honda places the Accord alongside the Volvo S60, Saab 9-3, Lexus IS and Alfa Romeo 156.
There is also an element of cross-over, according to Honda, where both the Volkswagen Passat and Audi A4 encroach into the 'quality' segment. So Honda's new diesel engine has to be a match for Ford's 128bhp TDCi, Audi's 1.9 TDI 130 and BMW's 2.0-litre common rail diesel.
The engine – dubbed i-CTDi for intelligent common rail turbo diesel injection – has been designed solely for the European market. About 30,000 are expected to be built during the first full year of production, although Honda expects to increase volume to cope with diesel demand in both the Accord and CR-V.
The new manufacturing process used 'semi-solid' casting of the aluminium block to increase strength compared with liquid casting. The result means the 2.2-litre unit is equal in weight to a 1.7-litre iron block equivalent.
Although it is more costly to produce than a petrol engine, Honda says it is no more expensive than other diesel motors.
Honda has gone to great efforts to reduce noise from the engine, including a dual-mass flywheel, a 'pendulum' engine mount system, balancer shafts, acoustic engine cover and even using thicker windscreen glass.
The diesel comes as Accord sales are already exceeding expectations in Europe, with accumulated sales in May more than 30% ahead of plans.
Kenichi Nagahiro, project leader for the diesel engine, said: 'There is no doubt that with the introduction of the i-CTDi, the development of the Accord is complete. Our aim in the development of the Accord series is for it to be a true global car with pride.'
He said that although the engine in its present state would achieve Euro IV emissions criteria, Honda was developing its own particulate filter to ensure it would comply with future emissions legislation, and more details would be announced at September's Frankfurt Motor Show.
He said that although the 2.2-litre was currently the only diesel engine being built by Honda, it was likely that smaller capacity units would be developed in the future if this engine was successful.
Behind the wheel
ALTHOUGH my visit to Honda's research and development centre is Offenbach in Germany was primarily to obtain the first details of the new engine, there was a car available to drive on a short route.
The car was a development prototype and unrepresentative of production models, but first impressions of the engine are impressive.
When we get to drive vehicles on the press launch in October, we can expect them to be just about as smooth as anything currently available in the sector, and that includes the new Jaguar X-type.
Engine noise will be subdued, even at lower speeds, and a steady 70mph on the motorway will be achieved in near silence with a little more than 2,000rpm showing on the rev counter.
With 251lb-ft on offer from 2,000rpm, it is more than a match for most engines in this class on maximum torque, and should respond well from 1,500rpm.
If Honda's claimed 52.3mpg on the combined cycle and 143g/km can be independently validated, this will only add to the appeal of an engine that will be among the very best available on the market.
ALTHOUGH I only drove a few miles in the Accord diesel, the early indications are very good. Honda's engineering know-how is highly regarded in the industry and the i-CDTi engine is likely to continue to add to that reputation.
Make: Honda Accord 2.2 i-CTDi
Engine (cc): 2,204
Max power (bhp/rpm): 138/4,000
Max torque (lb-ft/rpm): 251/2,000
Top speed (mph): N/A
0-62mph (sec): 11.0
Fuel consumption (mpg): 52.3
CO2 emissions (g/km): 143
On sale: January 2004
Price (est): from £18,500