During creation of the SkyActiv system engineers of the Japanese concern Mazda first of all wanted to reduce consumption of fuel and blowouts of harmful substances to the environment. These two desires are dictated by modern standards and fashion of engine building. But the Mazda company would not be Mazda if together with the above described tasks it did not try to make the cars well steered, dynamic and safe. The Skayaktiv technology is complex of innovations which has concerned engines, transmissions, bodies and the chassis. The first cars of the Mazda company with new Skayaktiv technology was to Mazda CX-5, the second Mazdas 6 of the third generation.
Petrol SKYACTIV-G motor.
The SKYACTIV-G gasoline engine – result of laborious work of engineers of Mazda. Having attentively analysed fundamental laws of thermodynamics, engineers of the company Mazda showed to the world absolutely revolutionary serial motor with value of compression ratio in 14:1. Similar values till this time were peculiar only to sports cars. The high compression ratio has allowed to reduce fuel consumption by 15%, but at the same time to make the engine more powerfull – torque has increased by the same 15%. At all this the new engine has fitted into rigid environmental standards of Evro6. In order that the power plant without detonations used gasoline with octane number 95, the Japanese engineers have developed absolutely new buckets which have allowed to increase efficiency of combustion procedure of fuel blend. The gas distribution mechanism has got phase shifters with electric drives, the exhaust manifold has received the scheme of conclusion of exhaust gases 4-2-1, new to Mazda, which allows to avoid excessive circulation of gases between cylinders of the engine and, thereby, to reduce pressure in combustion chamber.
Length of channels of a final collector was calculated very precisely since short channels would lead to the fact that the fulfilled gases could manage to get into the combustion chamber of the next cylinder until closing of the valve, and too long channels would lead to the fact that the catalyst will longer get warm to indicators of working temperature. Also absolutely new fuel nozzles which, having multi point sprayers in the construction, give the chance very evenly to spray fuel on all surface of the combustion chamber were developed.
For increase in overall performance of the motor it was also necessary to minimize “pumping losses” which are observed at lower loads of the motor when during an admission clock period – pistons inhaust air at the movement down. The amount of air in cylinders is under control of a throttle which is on an input of an inlet header. When the motor works at low loadings, respectively and the amount of air should be smaller. The butterfly valve is almost closed and it leads to the fact that pressure in an inlet header and cylinders is lower, than atmospheric. As a result of this process – pistons overcome a strong vacuum, i.e. so-called “pumping losses” which naturally affect the level of overall performance of DVS. A bad point here one – bad combustion. It turns out so that inlet valves remain in open position even at the time of the beginning of compression stroke that inevitably leads to reduction of pressure in cylinders and by that ignition of fuel air mixture is complicated. But engineers of the company Mazda not for nothing increased a compression ratio, it allowed to reach necessary indicators of temperature and combustion chamber pressure and, thereby, despite “pumping losses”, process of combustion remains effective and stable.
The SkyActiv technology means also weight reduction of the power unit. Japanese managed to lose the weight of pistons for 20 percent, connecting rods for 30 percent. The friction coefficient decreased by 38 percent. The cooling system was equipped with a pump with the impeller which is made of low-powerful composite material.
Diesel SKYACTIV-D motor.
The diesel unit works with the same compression ratio, as well as petrol 14:1. It also is surprising since diesel motors in the lump have a compression ratio in the range from 16 to 18. If the compression ratio at the diesel engine is less, then temperature and pressure in combustion chambers at final compression stroke are lower. And it, in turn, means that combustion goes in a slowed-up way that gives the chance to inject fuel even when approaching to upper dead point, but not as at diesels with a high compression ratio when the piston already moves down. At such situation fuel interacts with air much better and combustion goes better. At the same time gas with the minimum content of oxides of nitrogen and soot gets to an exhaust. In spite of the fact that diesel Mazda with the SkyActiv-D engine has no expensive converter of particles of nitrogen in the equipment, the power unit perfectly fits into environmental standards of Euro 6. It is necessary to add that extent of expansion on this engine above normal indicators and as the result an expense of a solyara decreased by 20 percent.
Because compression ratio low, it is known – it can affect operation of the motor at low temperatures. In this situation the Japanese engineers have completed the power plant with ceramic glow plugs and the VVL(Variable Valve Lift) system which prevents combustion misses thanks to the valve with the changeable height of rise for outlet valves. It is known that one combustion period is quite enough for temperature increase of exhaust gases. Therefore, leaning on this fact, in the SkyActiv-D engine, thanks to the VVL system, final the valve during timing period of admission are a little slightly opened and thanks to it hot exhaust gases can back return to cylinders and increase temperature of inlet air. This process allows to increase compression temperature and to save the engine from admissions of ignition in the course of warming up of the engine.
SKYACTIV-DRIVE AUTOMATIC TRANSMISSION.
Generation of hi-tech automatic transmissions of SkyActiv-Drive, provides great efficiency in torque transfer at the expense of the wide range of application of blockage of the hydraulic torque converter. This box gives smooth and fast switchings. Quickly reacts to changes of loads of DVS on small turns thanks to what gives the chance minimum to consume fuel. The expense fuel from this automatic transmission has decreased up to 7 percent. The main character of boxes Skayaktiv Drive is gidrotrasformator with 6 steps and full range of blockage of clutch for all 6 drives. Blocking of clutch has been increased to 89 percent.
SkyActiv-MT is absolutely new MKPP from the company Mazda. Ey have made easier and more compact. The coefficient of internal friction of details of MKPP became much lower that gives to the car good fuel economy. Features of this MKPP it is possible to call: the short course and easy inclusion of drives that gives sports highlight when driving.
Body of SKYACTIV-Body and SKYACTIV-Chassis chassis.
The new generation of body of SkyActiv-Body weighs 8 percent less, than previous. Also the new body can add high-strength and high ruggedness on torsion to the asset. All this has become possible thanks to high-strength staly – their share has increased from 40 to 60 percent.
The SkyActiv-Chassis chassis has received simplification on weight in 14 percent. Mazda has been developed by engineers the steering electrical system which have allowed to get feeling of pleasure from driving at any speeds. Fastenings of windscreen pillars of absorbers have been established so that to set bigger working in motion to the lever. Medium-rate maneuverability and high-speed stability increase quality of driving at any speeds that is reached due to revision of functional arrangement of all elements of suspender and steering.