New for the 2021 model year, the Mazda CX-30 debuts the upgraded Skyactiv-G and Skyactiv-X petrol engines. Renamed ‘e-Skyactiv G’ and ‘e-Skyactiv X’, the petrol engines are matched to the Mazda M Hybrid 24v mild-hybrid system and delivers increased performance and even more efficiency compared with the outgoing engine. The Mazda CX-30 range features manual and automatic transmissions, plus all-wheel drive and conventional front-wheel drive layouts.
The updated 2.0-litre e-Skyactiv G engine is exclusively matched to front-wheel drive with a choice of automatic or manual transmission across all five trim levels. Producing 122ps at 6,000rpm and maximum torque of 213Nm at 4,000rpm it features optimised intake port and piston shapes, split fuel injection, a coolant control valve and cylinder deactivation, to deliver higher levels of dynamic performance, fuel economy and environmental friendliness. The e-Skyactiv G 2.0-litre engine produces 7-8g/km less CO2 than the outgoing engine and adopts the company’s intelligent Mazda M Hybrid system to support greater gains in fuel economy and more driving pleasure.
The e-Skyactiv G’s cylinder deactivation system further improves efficiency by shutting down two of the engine’s four cylinders in light-load situations, such as when cruising at a constant speed. Shutting down the two outer cylinders increases the load on the remaining two, causing them to operate in a range of greater efficiency. Airflow intake volume, fuel injection rates and ignition timing are precisely controlled to allow the engine to switch smoothly between two-cylinder and four-cylinder operation and reduce fuel consumption when cruising at constant speeds.
Accounting for around 46 percent of UK CX-30 sales, the ground-breaking Spark Controlled Compression Ignition (SPCCI) e-Skyactiv X petrol engine is also offered across all grades with a choice of transmission. Exclusively available in GT Sport and GT Sport Tech trims, the e-Skyactiv X engine is available with Mazda’s latest advanced i-Activ all-wheel drive system.
Thanks to its unique combustion method in which spark plug ignition is used to control compression ignition, the resulting efficiencies mean this 186ps petrol SPCCI engine delivers excellent economy combined with lower CO2 emissions and flexible performance. The latest 2.0-litre e-Skyactiv X engine produces 186ps at 6,000rpm and maximum torque of 240Nm at 4,000rpm an increase of 6ps and 16Nm respectively. 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 also been improved, with Co2 emissions dropping by 5 to 11g/km – depending on transmission and trim level. Corresponding drops in WLTP combined economy further increases the appeal of Mazda’s unique SPCCI petrol engine
As an example the e-Skyactiv X AWD GT Sport automatic now emits 11g/km less Co2 with a 2.4mpg improvement in combined WLTP economy, while the entry-level front-wheel drive manual SE-L Lux is 6g/km cleaner and is 2.5mpg more fuel efficient. With emissions as low as 127g/km and WLTP combined economy as high as 50.4mpg, the e-Skyactiv X engine is the perfect solution for private and fleet customers, offering the ideal alternative to diesel in a segment that has seen demand for diesel powered cars dramatically reduce.
While Mazda is committed to diesel and the development of next-generation clean diesel engines for appropriate sectors, the abilities of Skyactiv-X Technology and diminishing consumer demand for diesel engines in the compact SUV segment mean that in the UK the Mazda CX-30 will be exclusively petrol. One of the principle points of focus in Mazda's long-term technology development strategy, Sustainable Zoom-Zoom 2030, is the need to significantly lower CO2 emissions. And the company is committed to reducing its global average 'Well-to-Wheel' CO2 emissions to 50% of 2010 levels by 2030, and to 90% by 2050.
At Mazda, we believe that multiple solutions are required to effectively lower CO2 emissions from road transport. With two thirds of global electricity production currently relying on the use of fossil fuels, Mazda believes regulations placing the emissions of an electric vehicle (EV) at zero to be disingenuous. Indeed, when converted to a 'Well-to-Wheel' figure, the average CO2 emissions of an EV in some regions can be rather close to those of a conventional vehicle, depending on the energy mix from which the electricity is made.
As the majority of cars will be fully or partially powered by internal combustion engines for many years to come, improvements made to these engines will have a greater effect on the reduction of total emissions, simply because of the number of vehicles that will benefit from them. Accordingly, Mazda has been looking to significantly reduce CO2 emissions from petrol engines based on the analysis of the control factors given by combustion chemistry and physics.
Featuring Spark Controlled Compression Ignition (SPCCI), a Mazda unique combustion method, the Skyactiv-X Technology represents a step in Mazda’s quest to develop a petrol engine with the ideal internal combustion mechanism. Developing controlled compression ignition for petrol engines has long been a goal of engineers. The recently updated e-Skyactiv X (formerly Skyactiv-X) is a ground-breaking engine, exclusive to Mazda, in which spark plug ignition is used to control compression ignition, resulting in dramatic improvements across a range of important performance areas.
The benefits of a spark-ignition petrol engine-expansiveness at high rpm and cleaner exhaust emissions- have been combined with the improved fuel-economy of a compression-ignition diesel engine – to produce a crossover engine that delivers the best of both worlds. The Skyactiv-X was the world’s first production petrol unit to exploit the benefits of compression ignition. Key to its operation is the use of a highly lean, fuel- and emissions-efficient mixture of air and fuel: 2-3 times leaner than in today’s conventional petrol engines. This mixture contains so little fuel that a normal engine with spark plugs cannot fire it.
Mazda already uses uniquely high compression ratios on its current Skyactiv petrol engines to reduce fuel consumption. This lead to the idea of increasing the compression ratio even further and igniting the fuel simply by compression as is the norm in modern diesel engines, this concept has been tried before by several manufacturers with Homogeneous Charge Compression Ignition (HCCI), but none has been able to expand the area of lean compression ignition across a wide range of engine operation.
Mazda’s unique solution to this challenge is Spark Controlled Compression Ignition (SPCCI) which allows the engine to switch seamlessly between conventional combustion and compression ignition by using a spark to trigger both types of combustion in different ways. In SPCCI mode, a split injection process creates separate zones of fuel-air mixture inside the combustion chamber, first, a very lean fuel to air mixture is injected into the combustion chamber during the intake stroke, then a zone of atomised fuel is precisely injected directly around the spark plug during the compression stroke.
Because of the high 16.3:1 compression ratio of Skyactiv petrol technology, the first injection of fuel is on the verge of spontaneously combusting anyway. To ignite the mixture at the right time, the small injection of atomised fuel directly around the spark plug builds a richer core. When the spark fires, it ignites the local zone of fuel and air. This increases pressure and temperature in the combustion chamber to the point where the main volume of the lean mixture rapidly combusts. To achieve even greater combustion efficiency, updates to Mazda’s 2.0-litre Sparked Controlled Compression Ignition engine, e-Skyactiv X, have been achieved through adjusting the compression ratio from 16.3:1 to 15.0:1.
Other modifications to the e-Skyactiv X engine 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 ensures e-Skyactiv X not only delivers higher maximum engine torque but also improved real-world fuel economy. The intake valve timing has been adapted through modifying the intake camshaft, this leads 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.
Improving fuel economy, SPCCI works in almost all ranges of engine operation except during cold starts, initial warm-up phases and at very high load. Under these circumstances, the engine seamlessly switches to normal operation, igniting a conventional ‘stoichiometric’ fuel and air mixture of 14.7:1. Because SPCCI is so stable whereas HCCI wasn’t, it can be used more frequently in the engine’s operating range, which means the engine can run for a higher percentage of the time in a very efficient mode. As a result, torque output is approximately 10% greater than that of the old e-Skyactiv G 165ps engine in the outgoing Mazda3.
In both the e-Skyactiv X and e-Skyactiv G CX-30, Mazda’s petrol engines are matched the company's intelligent Mazda M Hybrid system. Compact and efficient, the mild hybrid system features a belt-driven integrated starter generator (ISG) and a 24V lithium-ion battery. It supports greater gains in fuel economy by recycling energy recovered during deceleration and powering the ISG, functioning as an electric motor, to assist the engine.
The ISG converts the recovered kinetic energy into electric power and stores it in the lithium-ion battery. The system then uses a DC-DC converter to transform that voltage to the appropriate level, and supplies it to the car’s electrical equipment. Adopting the belt-driven ISG also delivers a refined drive feel by enabling the system to provide drive assist and helping the engine restart more quickly and quietly after shutting down for idling stop. The lithium-ion battery is mounted between the wheels, minimising its impact on interior space, while helping to optimise weight distribution and contributing to collision safety.
In addition to the updates to the e-Skyactiv petrol engines, the Mazda M Hybrid mild-hybrid system has had a software update that enables 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.
The Mazda M Hybrid system's brake-by-wire technology smoothly and dynamically blends electric and friction brake forces to maximise both stopping power and energy recuperation efficiency. Not only does it offer short braking distances with high levels of vehicle stability, but also - through the transformation of electric brake force into useable energy - further reductions in CO2 emissions. The electronically controlled brake-by-wire system is also designed to revert to entirely mechanical friction braking as a fail-safe in the event of an electrical system failure.
From GT Sport onwards e-Skyactiv X CX-30s can be matched to Mazda’s i-Activ AWD system, which thanks to its evolved control system and technologies to reduce friction, delivers real-world fuel economy almost on a par with a front-wheel drive vehicle.
Featuring ‘four-wheel vertical load’ detection to control torque distribution between the front and rear wheels, enhancing traction and grip regardless of the driving scenario, it also significantly reduces overall mechanical loss and contributes to improved fuel economy.
Friction-reducing technologies include a rubber damper inside the power take-off unit that greatly reduces fluctuations in input torque sent to the rear-wheel-drive unit, and a setting that applies a slight difference in the deceleration ratio between the power take-off and rear differential. By quickly adjusting torque distribution only when necessary, the system features positive response and enhanced real-world fuel economy.
The rear differential reduces mechanical loss by adopting ball bearings and the use of low-viscosity oil, along with a design that stores oil in the upper part and supplies just the necessary amount where and when required. Acting in combination, these measures increase the precision of the AWD-control unit while significantly reducing overall mechanical losses.
All-wheel drive can be matched to either a manual or automatic transmission, ensuring anyone can enjoy the benefits of increased traction with their e-Skyactiv X Mazda CX-30.