The second-generation Mazda 6 was launched in November 2007 and represented an evolution of Mazda Zoom-Zoom.
Mazda 6 has always been a driver's car and with the launch of the new-generation model last year, the fun factor was improved even further. The second-generation Mazda 6 was introduced originally with four different engines - three lively MZR petrol engines (in 2.5, 2.0 and 1.8-litre displacements) delivering power between 170 PS to 120 PS, and a MZR-CD 2.0-litre common-rail turbo diesel producing 140 PS and 330 Nm of torque. Mazda now introduces a new clean turbo diesel in three power derivatives that is one of the quietest and most powerful in its class.
Mazda's new MZR-CD 2.2-litre turbo diesel has a lively yet cultivated character that will offer a truly exclusive driving experience under the bonnet of the second-generation Mazda 6. Offered in three versions producing 185, 163 and 125 PS of maximum output and powerful torque of 400, 360 and 310 Nm respectively, the MZR- CD 2.2 will meet the demands of a wide spectrum of customers in Europe.
Delivering the Power - Output and Torque
To realise this kind of power and torque with 2.2-litres of displacement, the MZR-CD 2.2 employs a highly efficient variable-geometry turbo charger (VGT) with curved (instead of straight) vanes on the turbine (exhaust) side. This increases maximum available torque at both low and high engine speeds, while also increasing all-important low- end response (as low as only 1,800 rpm with a lat maximum torque curve that continues until 3,000 rpm) that contributes smooth and powerful driving feel. When combined with an abradable seal on the compressor side (intake side), which reduces the clearance between the blade and the compressor housing, these deliver superior turbocharger response at just about all engine speeds.
Converting the engine's combustion energy into this much engine torque meant the pistons had to be designed to take the resulting high combustion pressure and temperatures. As a consequence, the pistons are made of an aluminium alloy with improved high- temperature fatigue strength. A half-Keystone cross-section top- ring with improved carbon scavenging abilities is used, and the groove for the top ring is made more durable with the adoption of a cooled ring carrier that increases the groove's cooling capability.
Mazda engineers also increased the fuel injection pressure to 200 MPa (by comparison, the previous generation MZR-CD 2.0- litre turbo diesel uses 180 MPa). They realised this by making functional improvements to the high-pressure pump, among other improvements, and by new injectors featuring 10 spray holes per injector (instead of the 6 spray holes for the MZR-CD 2.0-litre) that are smaller (reduced from 0.13 mm to just 0.119 mm). These changes enable more precise injection timing, and an increase in the number of times of injection and injection amount. And it allowed the fuel injection patterns at transitional states to be more precisely controlled. As a result, the Mazda 6 MZR-CD 2.2 provides superior acceleration in those situations you need it most, like entering the motorway. It also surpasses its competitors in lower speed acceleration. Acceleration in 3rd gear from 50 to 100 km/h, for example, is 1.7 seconds faster than the MZR-CD 2.0-litre.
Low Fuel Consumption
This new diesel engine also meets the requirements of Mazda's 'Sustainable Zoom-Zoom' plan by being frugal at the pump: all power derivatives use between 5.5 and 5.7 litres of fuel per 100 km (combined), some of the segment's lowest.
New injector with 10 spray holes
It achieves this by employing highly responsive solenoids for the common-rail injection system that achieve a minimum injection interval of just 0.2 ms (the MZR-CD 2.0 is 0.3 ms), which speeds up the minimum injection interval by about 30 percent, improves its responsiveness and lowers fuel usage. Fuel is also saved by lowering the compression ratio to 16.3:1 and utilizing the temperature cooling effect this causes, which secures more mixing time until ignition, and allows a more precise fuel-injection pattern. As a result, fuel consumption is a low 5.5 to 5.7 litres (depending on derivative) with CO 2 emissions from between 147 to 152 g/km. In fact, the MZR- CD 2.2-litre offers substantially higher power and torque than the previous-generation MZR-CD 2.0-litre, while delivering equal levels of fuel consumption and CO 2 emissions.
Low Emissions - Particulate Filter with World's First Ceramic Support Matrix Structure
Mazda engineers not only made the new 2.2-litre turbo diesel powerful and low consumption, they also lowered the amount of raw emissions and raised the efficiency of its after-treatment technologies. The engine's highly responsive fuel-injection technologies have new injectors (see above) that yield better atomized spray characteristics. These are combined with an exhaust-gas recirculation (EGR) system with a cooler bypass structure - that decreases unburned gases and NOx - and the high- response solenoids described above, to realise superior emissions performance without sacrificing power.
Emissions are then treated by a diesel particulate filter that uses a unique Mazda-developed, ceramic support matrix structure, which is the first of its kind to go into production in the world. Previous diesel particulate filters converted particulate matter (PM) into CO 2 by reacting the PM with the oxygen in the exhaust gas at the surface of the catalytic particle. This meant that the time needed for filter regeneration was determined by the amount of oxygen on the surface of the catalyst.
When the temperature of the exhaust gas is raised to quicken the regeneration time, then technological issues - like higher fuel usage or the ceramics exceeding their thermal resistance limit - can occur. Mazda solved these issues by using highly thermal resistant material for the ceramic monolith of its new diesel particulate filter, and designing the internal structure of the ceramic support matrix with passages for oxygen to enable a large amount of oxygen to be utilized for PM combustion. With this, Mazda has succeeded in significantly increasing the PM combustion speed. As a result, the number of times the diesel particulate filter has to regenerate (in combined mode) is cut in half, and the time necessary for each regeneration phase is shortened by one third. For owners of the new Mazda 6 MZR-CD 2.2-litre turbo diesel, this means worry-free filter regeneration and, because fewer regeneration phases are required and each takes less time, less fuel consumption overall.
Running Quiet
The new Mazda 6 MZR-CD 2.2-litre common-rail not only offers superior output, fuel economy and emissions performance, it is also one of the quietest engines in its segment with this amount of torque. This ensures a driving experience that is one of the non- premium segment's most exclusive. To achieve this, the new engine has a lower block with a very rigid aluminium-alloy structure, with the bottom of the cylinder block skirt and the cylinder block's main bearing caps bolted to the lower block at 18 separate locations. This high structural rigidity is combined with a front chain-driven cassette-type balancer shaft to suppress booming noise and lower radiated noise, and to deliver optimised pedal response and engine sound for a reined acceleration feel.
Packaging and Weight Management
Keeping the new MZR-CD 2.2-litre engine as close as possible in size and weight to that of the MZR-CD 2.0-litre diesel was a key factor in ensuring exhilarating performance combined with fuel efficiency and low emissions. Some of the newly adopted technologies, such as the balancer shaft and DOHC, result in increased size and weight. Nonetheless, numerous innovations were added to manage size and weight increases, with the goal of maintaining packaging and keeping the weight increase within just 6.0 kg of the previous MZR- CD 2.0-litre turbo diesel.
Due to the increase in displacement, the stroke of the MZR-CD 2.2 was lengthened by 8 mm compared to the MZR-CD 2.0. At the same time, the overall length of the connecting rods was shortened by optimizing their design. As a result, their weight remains at the same level as in the MZR-CD 2.0. The adoption of a balancer shaft that decreases vibration caused by reciprocating motion made a thinner cylinder block with fewer ribs possible (if the MZR-CD 2.2 had no balancer shaft, the cylinder block would have been 1.9 kg heavier than that of MZR-CD 2.0, and its crankshaft 1.3 kg heavier.). Furthermore, decrease in size and weight was achieved by making the balancer housing, oil pump housing, and the oil suction pipe a single structure. To achieve even more weight reduction, while increasing the cooling capability of the new engine, the oil cooler is made of aluminium (-0.6 kg). The weight of the cam cover is also reduced by making it out of plastic (-1.0 kg).
Packaging and Weight Management
Keeping the new MZR-CD 2.2-litre engine as close as possible in size and weight to that of the MZR-CD 2.0-litre diesel was a key factor in ensuring exhilarating performance combined with fuel efficiency and low emissions. Some of the newly adopted technologies, such as the balancer shaft and DOHC, result in increased size and weight. Nonetheless, numerous innovations were added to manage size and weight increases, with the goal of maintaining packaging and keeping the weight increase within just 6.0 kg of the previous MZR- CD 2.0-litre turbo diesel.
Due to the increase in displacement, the stroke of the MZR-CD 2.2 was lengthened by 8 mm compared to the MZR-CD 2.0. At the same time, the overall length of the connecting rods was shortened by optimizing their design. As a result, their weight remains at the same level as in the MZR-CD 2.0. The adoption of a balancer shaft that decreases vibration caused by reciprocating motion made a thinner cylinder block with fewer ribs possible (if the MZR-CD 2.2 had no balancer shaft, the cylinder block would have been 1.9 kg heavier than that of MZR-CD 2.0, and its crankshaft 1.3 kg heavier.). Furthermore, decrease in size and weight was achieved by making the balancer housing, oil pump housing, and the oil suction pipe a single structure. To achieve even more weight reduction, while increasing the cooling capability of the new engine, the oil cooler is made of aluminium (-0.6 kg). The weight of the cam cover is also reduced by making it out of plastic (-1.0 kg).
Mazda 6 - the first Mazda with Rear Vehicle Monitoring System
Not only does the Mazda 6 2.2-litre diesel meet the requirements of Mazda's 'Sustainable Zoom-Zoom' strategy by delivering high power and torque with low consumption, it also meets the strategy's focus on improved safety by introducing a new vehicle monitoring system to the line-up as an enhancement to its already long list of active safety features. Employing two wide-angle, 24 GHz microwave radar units on the right and left side of the rear bumper, this system is a fully independent active safety feature that detects and warns the driver of an approaching vehicle - when driving at speeds over 60 kilometers per hour - before he has a chance to change lanes by mistake. It also detects vehicles driving in the blind spot area, and is effective even in bad weather conditions.
