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View Full Version : Next-Generation Clean, Green Diesel Engines



ShAwNeX
24-09-2007, 05:40 PM
http://www.honda.com.au/wps/wcm/connect/internet/honda.com.au/home/news/hondas+next-gen+clean+green+diesel+engines

FRANKFURT -- Honda’s President and CEO, Takeo ***ui, has unveiled two new clean diesel engines at the 2007 Frankfurt Motor Show.

The engines belong to Honda’s second generation diesel family -- named i-DTEC (intelligent Diesel TEChnology) -- which uses world-first technology to reduce emissions to a level equal to that of a petrol engine.

By further improving the current award winning i-CTDi's superb performance, fuel economy and emission efficiencies, i-DTEC has achieved various stringent emission standards in the U.S., Japan and Europe (Honda test data).

The first i-DTEC engine is set to make its driving debut in the new European Accord range in 2008.

The first engine on display on the Honda stand is a 2.2 litre that uses a combination of the latest injection technology, more efficient exhaust gas recirculation and a diesel particulate filter to exceed Euro 5 requirements without compromising engine performance. Both power and torque levels have been increased and fuel economy has been improved compared to the current 140 PS (102kW) engine.

In Euro 5 regulation, emissions of particulates from diesel-engined cars are expected to be reduced by 80 per cent compared to Euro 4 (down from 25 to 5 mg/km), while NOx levels are cut from 250 to 180 mg/km.

The second engine on display is a super-clean next generation diesel that achieves compliance with the stringent US Environmental Protection Agency (EPA) Tier II/Bin 5 emissions requirements through using a Lean-burn NOx-reducing Catalyzer. This is of particular significance to the European market in that the Tier II standards are even more demanding than the Euro 6 requirements which remain at the proposal stage.

Tier II is the second stage of US emissions standards and is split into eight permanent and three temporary certification levels called ‘bins' to which vehicles are certified. When fully implemented in 2009, a manufacturer's light-vehicle fleet has to meet the average NOx standard of approximately 43.5 mg/km (0.07 g/mile) - the Bin 5 level (and equivalent to California's LEV II standard).


How does Honda’s super clean diesel work?

Set to debut in the United States within the next two years, Honda’s next generation super-clean diesel engine (that will meet US Tier II emissions standards) features an innovative Lean-burn NOx-reducing Catalyzer that uses ammonia to 'detoxify' NOx, turning it into harmless nitrogen. Unlike Selective Catalytic Reduction (SCR) systems that use Urea supplied from a storage tank, Honda's technology uses ammonia generated directly within the catalytic converter.

It works using a two-layer structure: one layer absorbs NOx from the exhaust gas which, during periodic rich burn controlled by the engine management system, reacts with hydrogen from the exhaust gas – producing ammonia. This ammonia is then absorbed by the second layer.

During lean burn operation, the ammonia is used to convert the remaining exhaust NOx into nitrogen. Why ammonia? Well, it is a great reagent for reducing NOx into nitrogen in oxygen-rich, lean-burn atmospheres. The system also provides more efficient NOx reduction in the most critical temperature range of 200-300°C for diesel engine exhaust systems.

Petrol engines currently use three-way catalytic converters that give NOx reduction rates as high as 99 per cent, but this performance is only possible when the exact proportions of air and fuel are present for the reaction to take place. By comparison, in a diesel engine, three-way catalytic converters only reduce NOx levels by approximately 10 per cent. Honda's new technology efficiently reduces NOx in a lean-burn atmosphere, enabling diesel engines to rival petrol engines on cleanliness.

The system is compact too, which means it can easily be installed downstream of the standard diesel catalytic converter and particulate filter.

Alongside developing exhaust gas cleaning technology, Honda also plans to address other technical challenges in developing clean diesel engines, like handling diesel fuels with different cetane numbers and meeting US On-Board Diagnostic System requirements.