Press Release
Powertrains – A Complete Line Up
The Mazda5 engine line up features two MZR-CD common-rail diesel derivatives with a maintenance-free diesel particulate filter system standard, coupled to a new six-speed manual transmission, along with two spirited MZR petrols. These powertrains are tuned to take full advantage of the car’s aerodynamic form and compact dimensions to deliver Zoom-Zoom driving fun for up to seven people.
Diesel Powertrains
• Two derivatives of the MZR-CD 2.0-litre common-rail turbo diesel
• Maintenance-free diesel particulate filter standard
• Power, robust torque and low consumption and emissions
• New six-speed manual transmission
With two derivatives of Mazda’s improved MZR-CD 2.0-litre turbocharged common-rail diesel engine, Mazda continues to deliver everything the growing number of diesel customers in Europe demand: solid performance, smooth petrol-like operation and outstanding fuel economy; with a catalyzed diesel particulate filter system standard for Euro Stage IV emissions on both derivates. The MZR-CD 2.0-litre Standard Power version is designed for good power and torque with low fuel consumption, while the High Power version is designed for those looking for even more performance.
Mazda5 diesel engines employ a variable-geometry turbocharger, which maximizes torque across a wide range of engine speeds. It has an optimized design that makes it smaller, with a turbine that has a lower inertia moment. This gives the engine a smooth, linear acceleration and high maximum output. It also makes 300 Nm of torque available as low as 1,500 rpm for excellent engine response across the speed range. The Standard Power version of the MZR-CD 2.0-litre engine produces 81 kW/110 PS of power at 3,500 rpm and a maximum torque of 310 Nm at just 2,000 rpm with a top speed of 179 km/h. The High Power version produces a maximum 105 kW/143 PS of power at 3,500 rpm and robust maximum torque of 360 Nm at 2,000 rpm with a top speed of 197 km/h.
NVH and Low Fuel Consumption
Employing diesel engines in the new Mazda5 was a special challenge for Mazda engineers, since both derivatives are heavier, have higher torque and could potentially create higher noise levels than a petrol engine. Several technologies are employed to keep noise and vibration to near petrol levels.
Reducing diesel engine noise and vibration begins with optimized combustion. Mazda5’s diesel engines employ a common-rail injection system with ultra-high pressure of up to 1800 Bar and multi-stage injection of up to six times per cycle, depending on operating conditions. Multi-stage injection prevents overly rapid pressure increases in the cylinders and suppresses knock and overall combustion noise. The engine uses pilot injection (pre-injection) at low engine speeds. During this process, a small amount of fuel is injected into the cylinder before main injection, which reduces combustion noise considerably.
Mazda5 employs a dual-mass flywheel that limits engine noise and vibration, along with extensive noise and vibration insulation that prevent noise from reaching the cabin (see Chapter 4).
Despite delivering power and high torque, Mazda5’s diesel derivatives use low amounts of fuel. This is accomplished by various engine technologies. The common-rail system, for instance, uses improved six-hole injectors to produce the best possible fuel atomization. Fuel injection volume, frequency and timing are electronically optimized based on accelerator pedal position, engine speed and other variables, to optimize combustion efficiency. Due to the modified pistons of Mazda5’s MZR-CD 2.0-litre, a low compression ratio of 16.7:1 is achieved. This lowers pumping losses, improves thermal efficiency at middle and high engine load and improves fuel consumption. In addition, the low compression ratio reduces the engine’s idling noise significantly. Combined with its new six-speed transmission, these technologies keep fuel consumption down without sacrificing Zoom-Zoom driving enjoyment.
Emissions
To achieve Euro Stage IV compliance, Mazda5’s MZR-CD 2.0-litre diesel derivatives employ a combination of modern engine technology and a new diesel particulate filter system. The engine itself is designed to produce as few toxic emissions as possible during combustion, while still ensuring lively, high-torque engine response. The engine’s multi-stage injection minimizes the amount of particulate matter (PM) remaining after combustion. The engines also have an electronically-controlled intake shutter valve and exhaust-gas-recirculation (EGR) valve to suppress the production of NOx.
Diesel particulate filter System – Euro Stage IV Compliance
These engine technologies are combined with a new catalyzed diesel particulate filter system that reduces PM emissions to almost zero and ensures Euro Stage IV compliance and lower operating costs in most countries. The system captures PM in a silicon carbide ceramic filter with a honeycomb structure consisting of square channels, arranged in staggered formation and closed off at alternative ends. PM contained in the exhaust gas accumulates at the porous dividing walls, while gases pass through the filter.
To prevent the filter from becoming blocked with PM, it must be “regenerated” at certain intervals. With the aid of a pressure-difference sensor located at the bulkhead of the engine compartment which measures the pressure difference in the exhaust gas flow upstream and downstream from the diesel particulate filter, three exhaust gas temperature sensors and an O2 sensor, the powertrain control module (PCM) monitors the PM amount in the filter. When filter capacity is reached, the PCM in conjunction with the common-rail injection system initiates burn-off of the accumulated particulates in the filter by injecting small amounts of fuel during the exhaust cycle and raising exhaust gas temperatures for a short period. Further measures to increase the exhaust gas temperature include closing the EGR valve and the intake shutter valve.
The new Mazda5 diesel uses a catalyzed diesel particulate filter with channels in the filter coated with platinum. This coating lowers the light-off temperature of the collected PM and allows filter regeneration at a lower exhaust gas temperature of 350 to 500 C° (depending on engine operating conditions). By using a catalytic diesel particulate filter, Mazda5 does not need a special fuel additive to reduce the light-off temperature, as some cars do, making the filter system maintenance-free.
To achieve the exhaust gas temperature required to burn off PM during the regeneration process, the amount of fuel injection is increased. However, the regeneration process of the diesel particulate filter represents a marginal part of total engine operating time, so its impact upon overall fuel consumption is minimal. Mazda5’s diesel derivatives with diesel particulate filter system meet strict Euro Stage IV emission standards while using only 6.3 litres of fuel per 100 km (combined) and producing 173 g/km of CO2.
Mazda5’s diesel particulate filter system is able to regenerate itself under normal driving conditions that combine a mixture of urban and extraurban driving. However, in highly unusual conditions (like continuous days of ultra-low speed driving) a diesel particulate filter indicator light on the dashboard will indicate that regeneration is required. The car should then be driven at a normal speed for 10 to 15 minutes (at an engine speed of 2000 rpm or higher and a vehicle speed of 40 km/h or more) to regenerate the filter.
Transmissions
Both diesel derivatives are coupled to a newly-developed six-speed manual transmission with a self-adjusting clutch, which are designed to deliver Zoom-Zoom driving fun by accommodating both engines’ high torque of up to 360 Nm. It has a three-shaft design, with a primary shaft and two secondary shafts that make it very compact. First, second and third gears have triple-cone synchronizers and fourth gear has a dual-cone synchronizer, which allow full utilization of the engine’s high torque at low revs, while delivering smooth shifting characteristics and improved
