Ford begins production of CNG-capable F-150
Porsche launches compact SUV Macan with diesel option

Mazda showcases CNG and hybrid Axela models in Tokyo; Mazda’s approach to environmental performance

At the Tokyo Motor Show, Mazda is showcasing the recently-released Mazda Axela (known as Mazda3 overseas) with a variety of engine types at the 2013 Tokyo Motor Show, including a CNG concept and hybrid variants. (Earlier post.)

The Axela accounts for more than 30% of global sales; the latest Axela is the third generation. The new Axela range also introduces a hybrid vehicle, and marks the first time for a single model launched on the Japanese market to include gasoline, diesel, and hybrid power plants in its powertrain lineup.

In terms of its overall approach to environmental performance, Mazda is pursuing CO2 reduction by globally deploying its SKYACTIV technology that re-engineers all of the vehicle’s base technologies from scratch. Mazda is reducing vehicle weight, as well as gradually introducing electric devices including battery management (idling stop), brake energy regeneration, and motor drive technologies.

In addition to the challenges posed by CO2 reduction, Mazda believes that a “multi-solution” approach supporting energy diversity is another key factor in realizing a sustainable future.

Even in 2020, Mazda expects that the world’s key energy sources will continue to be mainly petroleum based and that the majority of vehicles will still be powered by internal combustion engines. With this in mind, Mazda is working on the comprehensive improvement of base technologies using SKYACTIV drive and promoting its Building-Block Strategy in order to meet the company’s stated goal for 2015 of raising the average fuel economy of Mazda vehicles sold worldwide by 30% compared with 2008 levels. Click to enlarge.

Alternative fuels: CNG and E85. Using SKYACTIV-G as a base, Mazda is pursuing the practical use of both a CNG engine and a bioethanol engine that supports E85, the 85% ethanol blend. In this way, in addition to gasoline, diesel or electricity (hybrids), Mazda is providing a “multi-solution” that allows customers to choose a power unit and energy source appropriate to where they live. Mazda says that its ultimate goal is to preserve driving pleasure unchanged, no matter what fuel is used, as well as excellent environmental performance.

The Mazda3 SKYACTIV-CNG Concept unveiled at this year’s Tokyo Motor Show has dedicated features including a gasoline/CNG dual fuel engine based on the SKYACTIV-G 2.0 and a CNG tank.

Major technologies on Mazda3 SKYACTIV-CNG concept. Click to enlarge.

SKYACTIV-HYBRID, the Mazda hybrid system. Mazda introduced its hybrid system, SKYACTIV-HYBRID, to the Japanese-specification production model. The SKYACTIV-HYBRID-dedicated 2.0-liter gasoline engine adopts cooled Exhaust Gas Recirculation (EGR) that recirculates a portion of exhaust gas to the intake side, helping to realize a 14.0:1 compression ratio.

Mazda hybrid system. Click to enlarge.

Recovering thermal energy from exhaust gas shortens engine warm-up time, increasing the opportunities for engine stopping, and thereby improving fuel economy.

The transaxle splits motive power from the engine into drive power and power to the generator, and transfers a combination of motor power and engine power to the drive wheels.

The power control unit steps up/steps down power from the high-voltage battery and supplies it to the motor, the auxiliary equipment, and the auxiliary battery. In addition, it manages electrical power to optimize supply to the motor and high-voltage battery. Furthermore, the unit performs generator control to adjust engine load.

A high-voltage nickel-metal hydride battery is adopted that is specifically developed for automotive use, having a simple structure and superior stability. Current, voltage, temperature and other measures are computer monitored and controlled to constantly maintain optimum status, helping enhance durability.

In addition, the engine incorporates control systems that enable more efficient combustion of fuel over a wider range of driving. The engine adopts a 4-1 exhaust system.

i-ACTIVSENSE and Connect. The new Axela is equipped with the full suite of i-ACTIVSENSE, Mazda’s advanced safety technologies. In addition, the new Axela marks the debut of Mazda Connect, a car connectivity system.

ACTIVSENSE technologies include:

  • Forward Obstruction Warning (FOW). The system detects a vehicle travelling ahead and helps the driver avoid collisions by sounding an alarm when there is a risk of collision.

  • Rear Vehicle Monitoring (RVM). The system detects vehicles approaching on either side from the rear and alerts the driver to potential risks when changing lanes.

  • Adaptive Front-lighting System (AFS). The system controls the direction of headlights according to vehicle speed and steering inputs, enabling the driver to see further around curves at night.

  • High-Beam Control System (HBC). The system detects oncoming vehicles or vehicles ahead and automatically switches the headlights between high and low beams for safer nighttime driving.

  • Lane Departure Warning System (LDWS). The system detects lane markings on the road surface and warns the driver of imminent unintentional lane departures.

  • Mazda Radar Cruise Control (MRCC). The system judges the relative speed and distance to the car ahead, and works within a set speed range to maintain a safe following distance, thus alleviating some of the burden on the driver when driving on highways.

  • Smart City Brake Support (SCBS). If the system detects a risk of collision with a vehicle travelling ahead at speeds between approximately 4‒30km/h, it automatically applies the brakes and reduces engine output with the aim of avoiding the collision or reducing the severity of impact.

  • Acceleration Control for Automatic Transmission (Japanese-specification models only). The system comes into effect if the driver presses the accelerator pedal more than a prescribed amount when an obstacle is detected in front. It suppresses sudden acceleration by curbing engine output while alerting the driver with an alarm and a warning light on the meter display.

  • Smart Brake Support (SBS). This helps the driver avoid or reduce the severity of collisions, particularly when driving at speeds above 15km/h, by automatically applying the brakes if there is a danger of collision.



If anyone is able to offer a low cost gasoline/cng soultion for the USA, they will do very well.
[ This probably applies even more to SUVs than saloons ]
The US is awash in natural gas - they just need to find ways of running cars on it (cheaply and efficiently).
Ideally, you need some kind of hybridisation as well for urban use - problem is to keep the total cost and engine system size down.

Freddy Torres

Increases in efficiency are welcome no matter where they come from but I hope someday soon, all car companies realize that power has to come from the electric drivetrain while extreme efficiency must come from the internal combustion engine. Mazda found a winner with the skiactive technology since direct injection plus some other tricks have allowed this engines to have a 14:1 compression ratio while still using regular unleaded gasoline. Notice that the Toyota Prius has a compression ratio of 13:1 while the Prius C has a compression ratio of 13.4:1. This means that Mazda can easily increase the already high compression ratios of their skiactiv engines to more than 16:1 if they use their skiactiv technology in an Atkinson engine. This combination will produce an extremely high thermal efficiency at the expense of high power density and a decrease in torque. Keep in mind that an Atkinson engine with Skiactiv technology will be vastly superior in power density, thermal efficiency and torque when compared to a regular Atkinson engine.

To maximize performance, Mazda needs to pick the most power dense electric motors and the most power dense electric batteries. A good start would be two Yasa-750 electric motors with a total combined weight of 54Kg and total peak output of 400 kW (537 hp)and 150 kW (201 hp) of continious power. Next we can pick A123Systems around 150 Kg of AHR 32113 cylindrical bateries (around 750 single batteries). These batteries have a peak specific output of 2.7W per kg for 10 seconds. This peak output for both motors and batteries will be enough to get exellent times for both 0 to 60 mph and for the quarter mile. Keep in mind that the ICE can be linked to the front wheels (mechanically and/or electrically) for an additional boost in acceleration.

Lastly, all car companies must keep reducing the mass of their new cars. Replacing the 12V lead acid batteries with lithium ion technology can save up to 15 Kg of battery weight (roughly 1% of the total car weight).



The Ford F150 is a very good looking and popular truck so I'm surprised that they are only expecting to produce 15,000 CNG ready vehicles. Here in Alberta you get cng with taxes for about 40-50 cent per litre discount for energy equivalents, so if in the lifetime of the truck you burn 40,000 litres you save 15 to 20 thousand dollars in fuel which is less than the premium for installing the CNG tanks.

You would enjoy an even better discount if you were a fleet operator with your own compressor. 15,000 seems like a small number when you consider the large market for the truck and the favorable economics so It appears you can mostly attribute it to consumer reluctance to change. Granted there are space and fuel availability considerations, however, for many applications they would not be an issue.


A dual fuel diesel/DME hybrid would be good. DME is liquid at moderate pressure, so the tank is smaller. A diesel tank would be for backup and trips.


@ Freddy Torres,
According to some comments on another forum, Mazda SkyActiv engines (in non-hybrid version) are already Atkinsonized (to some degree), so there may not be too much room for improvement (as you suggested).

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