Engines &

The Mazda3 brings together a long-term vision for sustainability and a desire to deliver an outstanding driving experience. Featuring best-in-class Skyactiv technology, Mazda engines combine the benefits of petrol and electric drives for superior performance and driving pleasure of unprecedented quality.

Mazda’s sustainability strategy is expressed in its ‘Sustainable Zoom-Zoom 2030’ long-term technology development programme. As part of this vision for solving issues that impact the earth, Mazda applies a well-to-wheel philosophy. This end-to-end approach looks at carbon dioxide emissions throughout all stages of fuel extraction and vehicle operation. Viewed from this holistic perspective, internal combustion engines are forecast to continue powering most of the world’s motor vehicles in the future – Mazda will therefore work continually to improve the combustion efficiency and performance of its engines. At the same time, its engineers will gradually integrate electric drive technologies, such as the mild hybrid system used by the Mazda3’s Skyactiv-G 2.0 engine and Skyactiv-X engine. In keeping with the latest Euro 6d-TEMP emissions regulations, all engines used in the Mazda3 are homologated according to the requirements of the WLTP/RDE test cycle.

The Mazda3 is offered with a choice of two petrol engines: 122ps 2.0-litre Skyactiv-G and Skyactiv-X 180ps Spark Controlled Compression Ignition (SPCCI) engine. Across all trims these engines are offered with a choice of six-speed Skyactiv-MT manual or six-speed Skyactiv-Drive automatic transmission.

While it is based on the 2.0-litre petrol engine found in the outgoing third-generation Mazda3, the latest Skyactiv-G 2.0 high-efficiency direct injection petrol engine found in the Mazda3 features a host of new features including Mazda’s new Mazda M Hybrid system. The result is strong dynamic performance combined with excellent fuel economy and low particulate matter exhaust emissions. The unit develops 122 PS at 6,000 rpm and maximum torque of 213 Nm at 4,000 rpm. With a manual gearbox, it combines a combined fuel consumption of 42.2-45.6mpg with CO2 emissions of 136-147g/km - depending on trim/wheel size.

Compared to previous iterations of the engine, an upgraded piston skirt and optimised oil ring profile reduce mechanical friction, while the coolant control system promotes quick engine warm-up to reduce fuel consumption. Combustion noise has been refined and enhanced efficiency achieved through the optimisation of the piston top profile and multi-stage injection. And high pressure fuel atomisation from the injectors increases combustion efficiency by preventing fuel adhesion to the combustion chamber walls. On top of that, increased torque across the rpm range delivers the dynamic performance enhancement you’d expect from Mazda.

Another first for the Mazda3 is cylinder deactivation. Fuel economy in the evolved Skyactiv-G 2.0-litre is increased by virtually shrinking the displacement of the engine when possible. The system automatically switches between two-cylinder and four-cylinder operation depending on the driving conditions. Thus, the system shuts down cylinders one and four in light-load situations, such as when cruising at a constant speed. This reduces pumping loss and mechanical resistance. Airflow intake volume, fuel injection rates and ignition timing are precisely controlled to make the switch smooth. The driver is able to enjoy fuel savings without any noticeable change in the feel of driving the car.

Further adding to the efficiency of the Mazda3, Mazda’s new Mazda M Hybrid system is standard on the Skyactiv-G and Skyactiv-X engine. A compact and highly efficient 24V mild hybrid set up, the system minimises fuel consumption and supports greater gains in fuel economy by recycling energy recovered during deceleration and powering an electric motor that assists the engine. A belt-driven integrated starter generator (ISG) converts the kinetic energy recovered during deceleration into electric power and stores it in a lithium-ion battery with a capacity of 600kJ. The system then uses a DC-DC converter to convert the power to the appropriate voltage and supplies it to the car’s electrical equipment. The lithium-ion battery is mounted between the wheels to minimise any effect on interior space while helping to optimise weight distribution and contributing to collision safety. In addition, the Mazda M Hybrid system supports extended engine off for increased fuel economy.

Even better, the Mazda M Hybrid system not only enhances the car’s environmental performance but also ensures better drivability. When the car is starting, accelerating or coming to a stop, transitions feel smooth and natural. By substituting engine torque for motor torque, the hybrid system can reach the same acceleration as petrol engines while using less fuel. Furthermore, engine speed is promptly adjusted during upshifts in order to enhance the driver’s subconscious clutch operation. Thus, the driver enjoys all the benefits of a mild hybrid without any sacrifices in terms of driving pleasure.

A world first, Mazda’s Spark Controlled Compression Ignition SPCCI Skyactiv-X engine makes its debut in the Mazda3 and is expected to account for 60 per cent of UK sales, thanks to its combination of power, low Co2 and economy. Key to its operation is the use of a highly lean and emissions-efficient air to fuel mix, and the ability for the engine to switch seamlessly between conventional spark compression and combustion ignition, by using the spark plug to trigger both types of compression in different ways.

A series of injections first flood the combustion chamber with a lean mixture of fuel and air during the intake process, then a precisely injected richer zone of atomised fuel is added directly around the spark plug during compression. Because of the high 16.3:1 compression ratio, the first charge is close to spontaneously combusting anyway, and the injection of the richer mix creates an ignition in the local zone around the spark plug, which in turn increases pressure in the rest of the combustion chamber to the point where compression ignition occurs and the lean mixture ignites.

This SPCCI operation occurs during light load situations ensuring that the low fuel lean running condition improves economy and reduces emissions; however when the driver asks for more power the engine seamlessly switches to normal ‘stoichiometric’ fuel-air mixture of 14.7:1, while conventional combustion is only used under high engine loads and during very cold starts. The use of a spark plug to control compression ignition also avoids issues with knocking and unstable combustion.

The cleverness of Mazda’s SPCCI engineering is that the Skyactiv-X engine operates in its most efficient mode for more than 80 per cent of the time, delivering improved fuel consumption, lower emissions and more torque than the Skyactiv-G engine. Combining some of the advantageous elements of both petrol and diesel engines, plus CO2 emissions as low as 122g/km with the SE-L Lux trim saloon, Skyactiv-X offers performance and environmental credentials, making it a great option for customers coming from petrol or diesel cars.