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 multi-solution approach to sustainability strategy means Mazda still works continually to improve the combustion efficiency and performance of its engines. At the same time, its engineers will integrate electric drive technologies, such as the mild hybrid system used by the Mazda3’s e-Skyactiv G 2.0 engine and e-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.

Launched in 2020, the updated version of Mazda’s unique Skyactiv-X SPCCI Spark Controlled Compression Ignition petrol engine, renamed e-Skyactiv X, produces 186ps at 6,000rpm and maximum torque of 240Nm at 4,000rpm an increase of 6ps and 16Nm respectively compared to the previous Skyactiv-X engine. The torque improvement is most noticeable from 2000rpm onwards, however e-Skyactiv X’s torque output has improved in almost all engine speed ranges, and particularly under acceleration from partial-load driving situations most commonly found during daily driving. Even better, efficiency has improved, with CO2 emissions dropping by 6 to 11g/km – depending on model, transmission and trim level. Corresponding improvement in WLTP combined economy further increases the appeal of Mazda’s unique SPCCI petrol engine.

The updates to Mazda’s 2.0-litre Spark Controlled Compression Ignition engine have been achieved through adjusting the compression ratio from 16.3:1 to 15.0:1, while other modifications include the optimisation of combustion control, modified pistons and updating the Mazda M Hybrid mild-hybrid system’s software. This results in a broader operating band of combustion efficiency, which ensure e-Skyactiv X not only delivers higher maximum engine torque but also improves real-world fuel economy. The intake valve timing wasadapted through modifying the intake camshaft, which lead to a reduction in pumping losses and further increases the engine’s specific heat ratio, resulting in improvements to the e-Skyactiv X’s fuel consumption.

In addition to the updates to the combustion engine, the Mazda M Hybrid mild-hybrid system had a software update which enabled faster reactions of the system’s belt-driven ISGs torque control. This improvement on control smooths drivability by increasing or reducing torque control when needed. For example, when the e-Skyactiv X’s air supply unit turns on – to provide sufficient air needed for a lean combustion fuel-air mixture - or off again, the units inertia creates torque fluctuations. The Mazda M Hybrid’s enhanced software enables torque reactions issued through the belt-driven ISG that are quick enough to flatten the torque curve. As a result, the engine feels even smoother during linear acceleration.

Corresponding to the renaming of the e-Skyactiv X engine, Mazda’s 2.0-litre Skyactiv-G engine moved to e-Skyactiv G naming and also benefits from CO2 reductions compared with the previous generation Skyactiv-G engine.

While it is based on the 2.0-litre petrol engine found in the outgoing third-generation Mazda3, the latest e-Skyactiv G 2.0 high-efficiency direct injection petrol engine found in the Mazda3 and Mazda CX-30 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 122ps at 6,000 rpm and maximum torque of 213 Nm at 4,000 rpm.

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 was refined and enhanced efficiency was 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 was cylinder deactivation. Fuel economy in the evolved e-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 e-Skyactiv G and e-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 technology made its debut in the Mazda3 and accounts for around 46 per cent of 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.

The updated e-Skyactiv X engine, like the previous version, is unique to Mazda: 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 15:1 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 e-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 e-Skyactiv G engine. Combining some of the advantageous elements of both petrol and diesel engines, plus C02 emissions, e-Skyactiv X offers performance and environmental credentials in one package.