Technology of Hydrogen Fueled Rotary Engine | Dual Fuel System ( Hydrogen + Gasoline)

This hydrogen engine takes advantage of the characteristics of Mazda’s unique rotary engine and maintains a natural driving feeling unique to internal combustion engines. It also achieves excellent environmental performance with zero CO2 emissions.
Further, the hydrogen engine ensures performance and reliability equal to that of a gasoline engine. Since the gasoline version requires only a few design changes to allow it to operate on hydrogen, hydrogen-fueled rotary engine vehicles can be realized at low cost. In addition, because the dual-fuel system allows the engine to run on both hydrogen and gasoline, it is highly convenient for long-distance journeys and trips to areas with no hydrogen fuel supply.

01-renesis hydrogen rotary engine-reference exhibit (RE) technology-electronic controlled gas injection-EGR (Exhaust Gas Recirculation)-Dual Fuel system

Technology of the RENESIS Hydrogen Rotary Engine:

The RENESIS hydrogen rotary engine employs direct injection, with electronically-controlled hydrogen gas injectors. This system draws in air from a side port and injects hydrogen directly into the intake chamber with an electronically-controlled hydrogen gas injector installed on the top of the rotor housing. The technology illustrated below takes full advantage of the benefits of the rotary engine in achieving hydrogen combustion.

 

01-hYDROGEN FUELED ROTARY ENGINE CONCEPT-DUAL FUEL SYSTEM-WITH ELECTRONICALLY CONTROLLED HYDROGEN GAS INJECTOR

RE Features suited to Hydrogen Combustion

In the practical application of hydrogen internal combustion engines, avoidance of so-called backfiring (premature ignition) is a major issue. Backfiring is ignition caused by the fuel coming in contact with hot engine parts during the intake process. In reciprocal engines, the intake, compression, combustion and exhaust processes take place in the same location—within the cylinders. As a result, the ignition plugs and exhaust valves reach a high temperature due to the heat of combustion and the intake process becomes prone to backfiring.
In contrast, the RE structure has no intake and exhaust valves, and the low-temperature intake chamber and high-temperature combustion chamber are separated. This allows good combustion and helps avoid backfiring.
Further, the RE encourages thorough mixing of hydrogen and air since the flow of the air-fuel mixture is stronger and the duration of the intake process is longer than in reciprocal engines.

01-mazda-hydrogen RE technologies-Dual fuel Car-Hydrogen and gasoline-Hydrogen rotary engine

Combined use of Direct Injection and Premixing

Aiming to achieve a high output in hydrogen fuel mode, a direct injection system is applied by installing an electronically-controlled hydrogen gas injector on the top of the rotor housing. Structurally, the RE has considerable freedom of injector layout, so it is well suited to direct injection.
Further, a gas injector for premixing is installed on the intake pipe enabling the combined use of direct injection and premixing, depending on driving conditions. This produces optimal hydrogen combustion.
When in the gasoline fuel mode, fuel is supplied from the same gasoline injector as in the standard gasoline engine.

 

Adoption of Lean Burn and EGR

Lean burn and exhaust gas recirculation (EGR) are adopted to reduce nitrogen oxide (NOx) emissions. NOx is primarily reduced by lean burn at low engine speeds, and by EGR and a three-way catalyst at high engine speeds. The three-way catalyst is the same as the system used with the standard gasoline engine.
Optimal and appropriate use of lean burn and EGR satisfies both goals of high output and low emissions. The volume of NOx emissions is about 90 percent reduced from the 2005 reference level.

01-EGR System-Exhaust gas Recirculation-layout

Dual Fuel System

When the system runs out of hydrogen fuel, it automatically switches to gasoline fuel. For increased convenience, the driver can also manually shift the fuel from hydrogen to gasoline at the touch of a button.

01-dual fuel system-custom exhaust systems-RX7fp

Weight Reduction Technology | Fuel Economy Factors | Light Weight Technologies | Cutting Edge Technologies

01-mazda-weight reduction technology-good fuel efficiency-low exhaust emissions

Weight has a significant effect on a vehicle’s basic ability to go, corner and stop. Furthermore, environmental and economic factors such as fuel economy are also strongly influenced by vehicle weight.
Mazda strives to minimize the weight of every car it develops. The all-new Mazda2 (Demio) launched in July 2007 is a perfect example. During development, each individual part was examined and any unnecessary material was removed. The finished vehicle is around 100 kilograms lighter than the first generation Mazda2.
Mazda is committed to continually improve driving dynamics and fuel efficiency by deploying its lightweight technologies and resistance reduction techniques.

A dedicated team was formed to develop and test weight reduction techniques for the all-new Mazda2 well before actual vehicle development began. The team employed cutting-edge simulation software to analyze various methods. These were then tested against vehicle driving dynamics using prototype models.
This advanced technology development, conducted for Mazda’s new compact car, resulted in the creation of an impact absorbing concept that uses a new body framework and high tensile steel. Spot welding and weld bonds were also employed to strengthen specific locations that are subjected to greater loads. This has become Mazda’s new approach to weight management.

  • Bonnet

01-car bonnet design-car body design-car door design

With a smaller striker assembly and thinner hinges, the bonnet saves 0.69kg.

  • Body Shell

Smaller dimensions alone would have lowered the weight of the body shell by four kg, to 233 kg. Measures needed to increase rigidity and crash resistance would have then raised it up to 244 kg. But thanks to an optimised body structure, weight was reduced to 215 kg, 22 kg less than the old Mazda 2.

  • Door-Mounted Speakers

01-car mounted speakers

Mazda’s weight watchers were also at work with the door-mounted speakers. By changing the magnets from a ferrite type to neodymium, and making the plastic moulding single-peace, a total weight savings of 0.98 kg was achieved.

  • Intake and Cooling Systems

For the intake system, Mazda engineers moved the fresh air inlet from its original position behind the left headlamp to the top of the radiator shroud. This new position removed the need for the resonator and baffle.

  • Suspension

01-Mazda3_sedan_suspension_front

01-Mazda3_sedan_suspension_rear

Mazda weight specialists were able to save a impressive 13 kg using weight optimising measures in the suspension. These included making the trailing arm on the rear axle shorter and giving the front lower arms an open-section structure. This reduction in unsprung weight means both better handling and ride comfort.

  • Exhaust System

Mazda eliminated the underfoot catalyst, and for the 1.3-litre petrol model, the presilencer used in the Mazda2 until now was also eliminated.

  • Other points

01-Mazda3_sedan_airbags-chassis design

The shift lever assembly, base plate thickness and rib configuration for automatic transmission models were optimized. The shift knob itself was also made smaller and its positioning was improved. These changes saved 0.85 kilograms.