Mazda3 2.0D: Even More Appealing Than Before - Euro Stage4 Emissions | Part Three

Euro Stage4 Emissions

To achieve Euro Stage4 compliance, Mazda3’s 2.0 MZR-CD employs the latest in Mazda diesel engine technology and a diesel particulate filter system.  Its multi-stage fuel injection is programmed to keep particulate matter (PM) left over after combustion to a minimum.  The engine has an electronically-controlled intake shutter valve and exhaust-gas recirculation (EGR) valve to reduce the production of NOx.

These engine technologies are combined with Mazda’s catalyzed diesel particulate filter system that reduces PM emissions to almost zero and ensures Euro Stage4 compliance and lower operating costs.  The system is fitted with a silicon carbide ceramic filter with a honeycomb structure that captures PM in the exhaust, while letting gases pass through.

Over time, the captured PM accumulates at the porous dividing walls of the filter.  In order to prevent the filter from becoming blocked with PM, self regeneration takes place at certain intervals.  When this occurs is determined by the Mazda3’s powertrain control module (PCM), which monitors the amount of PM in the filter.

When filter capacity is reached, the PCM initiates burn-off of the accumulated PM in the filter by injecting small amounts of fuel during the exhaust cycle, raising the exhaust gas temperatures for a short period.  Further measures to increase the exhaust gas temperature are closing the EGR valve and intake shutter valve.

Mazda3 uses a catalysed diesel particulate filter with channels in the filter coated with platinum, which lowers the light-off temperature of the collected PM and allows filter regeneration at a lower exhaust gas temperature of between 350ºC to 500°C.  This means that the new Mazda3 MRZ-CD 2.0‑litre turbo diesel does not need a special fuel additive and is maintenance-free.  It also allows the diesel particulate filter system to regenerate under normal driving conditions that mixes urban and extra-urban driving.

Sporty Six-speed Manual Transmission from Mazda3 MPS

Mazda3 2.0 MZR-CD has a six-speed manual transmission based on the one used by the high-performance Mazda3 MPS.  With a self-adjusting clutch, it allows the driver to get the most out of the car’s high torque and power, delivering responsive driving fun in the first five gears, and low-noise cruising at motorway speeds in sixth gear.

The transmission has a three-shaft design, with a primary shaft and two secondary shafts that make it compact enough for application in Mazda3.  First, second and third gears have triple-cone synchronizers and fourth gear has a double-cone synchronizer, which allow full utilization of the engine’s high torque at low revs, while delivering smooth shifting characteristics and improved durability.  The transmission’s sixth gear also functions as an overdrive gear that uses engine output fully and allows high speed cruising without using high amounts of fuel.

continues... | Part Four
Published 11 April 2007 Melanie Carter

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