How do electric buses KAMAZ

How do electric buses KAMAZ electric, Drive, charging, Electro, electric bus, electric bus, "KAMAZ", this, electric buses, "KAMAZ", production, electric buses, see, transport, such companies, batteries, Toshiba

I now thought about it and realized that I had never been in production, where literally a huge, technically difficult product is produced from blanks, which leaves the factory shop on its own. That's exactly what I saw in Neftekamsk on the squares of NEFAZ, a subsidiary of KAMAZ PJSC.
It was possible to see how KAMAZ dump trucks, shift buses on an all-terrain chassis, trailers, tanks, NEFAZ buses are made. But Muscovites will probably be interested to see the process of assembling electric buses, which by the end of this year will already be in full swing on the routes of Moscow.
See ...
By tradition, to begin with, I offer a video version of my story:
To date, the Moscow Government has ordered the first batch of 50 vehicles from KAMAZ, which will be delivered by the end of this year. And the development of the electric buses at the KAMAZ Scientific-Technical Center began several years ago.
Photo 1.
How do electric buses KAMAZ electric, Drive, charging, Electro, electric bus, electric bus, "KAMAZ", this, electric buses, "KAMAZ", production, electric buses, see, transport, such companies, batteries, Toshiba

In 2016, the first pre-production prototype was actively tested in St. Petersburg, Moscow, Lipetsk, Naberezhnye Chelny.And now KAMAZ is ready to offer its products to the capital.
The production of the electric bus begins with similar metal profiles.
Photo 2.
How do electric buses KAMAZ electric, Drive, charging, Electro, electric bus, electric bus, "KAMAZ", this, electric buses, "KAMAZ", production, electric buses, see, transport, such companies, batteries, Toshiba

On special stands, workers (and for the production of trailers and trucks — robots) begin to make the carcass of the future vehicle.
Photo 3.
How do electric buses KAMAZ electric, Drive, charging, Electro, electric bus, electric bus, "KAMAZ", this, electric buses, "KAMAZ", production, electric buses, see, transport, such companies, batteries, Toshiba

The resulting blanks are combined into an increasingly complex structure.
Photo 4.
How do electric buses KAMAZ electric, Drive, charging, Electro, electric bus, electric bus, "KAMAZ", this, electric buses, "KAMAZ", production, electric buses, see, transport, such companies, batteries, Toshiba

What it reminded me of was the children's designer. These are the walls of the bus to be connected to the ceiling and floor.
Photo 5.
How do electric buses KAMAZ electric, Drive, charging, Electro, electric bus, electric bus, "KAMAZ", this, electric buses, "KAMAZ", production, electric buses, see, transport, such companies, batteries, Toshiba

The result is such a box.
Photo 6.
How do electric buses KAMAZ electric, Drive, charging, Electro, electric bus, electric bus, "KAMAZ", this, electric buses, "KAMAZ", production, electric buses, see, transport, such companies, batteries, Toshiba

It is sent to the spray booth (on the video you can see more about this) and primed.
Photo 7.
How do electric buses KAMAZ electric, Drive, charging, Electro, electric bus, electric bus, "KAMAZ", this, electric buses, "KAMAZ", production, electric buses, see, transport, such companies, batteries, Toshiba

As a result, here are the black frames on which the equipment begins to be hung.
Photo 8.
How do electric buses KAMAZ electric, Drive, charging, Electro, electric bus, electric bus, "KAMAZ", this, electric buses, "KAMAZ", production, electric buses, see, transport, such companies, batteries, Toshiba

Actually up to this point, the production of the electric bus is no different from the production of the KAMAZ bus.
Photo 9.
How do electric buses KAMAZ electric, Drive, charging, Electro, electric bus, electric bus, "KAMAZ", this, electric buses, "KAMAZ", production, electric buses, see, transport, such companies, batteries, Toshiba

But then begins the installation of power electrical equipment and electrical components and assemblies
Photo 10.
How do electric buses KAMAZ electric, Drive, charging, Electro, electric bus, electric bus, "KAMAZ", this, electric buses, "KAMAZ", production, electric buses, see, transport, such companies, batteries, Toshiba

Unfortunately, our industry is not yet ready to supply batteries of similar technical characteristics on a serial scale, so for now the Toshiba battery is put on the electric buses.
Photo 11.
How do electric buses KAMAZ electric, Drive, charging, Electro, electric bus, electric bus, "KAMAZ", this, electric buses, "KAMAZ", production, electric buses, see, transport, such companies, batteries, Toshiba

Actually, I discovered that in the electric bus there is a lot of equipment of a certain company Drive Electro.
Photo 12.
How do electric buses KAMAZ electric, Drive, charging, Electro, electric bus, electric bus, "KAMAZ", this, electric buses, "KAMAZ", production, electric buses, see, transport, such companies, batteries, Toshiba

After a closer look, it turned out that this is a private engineering company, the Russian leader in the design of electrical and hybrid systems for commercial vehicles and public land transport. Until 2014 - NIIEKU (Research Institute of Combined Power Installations). The company has collaborated with global automakers and has achieved results such as the first Russian electric bus and the first Russian trolley bus with a long autonomous power reserve.
The production facilities of Drive Electro are located in the city of Khimki, Moscow Region, now the localization level is 30%, and with the transition to mass production it can be gradually increased to 50%.
Drive Electro is known to market participants for its integration solutions for corporate and urban transport. The electric bus NefAZ-52992 (developed for the fuel company of Rosatom TVEL) became the first Russian-made electric bus with a mileage per charge of over 200 km and received a vehicle safety certificate.
Photo 13.
How do electric buses KAMAZ electric, Drive, charging, Electro, electric bus, electric bus, "KAMAZ", this, electric buses, "KAMAZ", production, electric buses, see, transport, such companies, batteries, Toshiba

Now back to the batteries of this electric bus.
In September 2017, Drive Electro and Japanese Toshiba reached an agreement on the warranty period for lithium-titanate rechargeable batteries for electric public transport developed and manufactured by Drive Electro using Toshiba Electronics rechargeable cells in accordance with the technical specifications for the city of Moscow.
Drive Electro batteries are designed for ultra-fast charging for 6–20 minutes, which is 20 times less than the average charging time of the first generation lithium-ion batteries. Due to the technological features of the Toshiba battery cells, fast recharging does not lead to degradation of the battery material and can be carried out at temperatures as low as -40 ° C without additional heating systems.
Photo 14.
How do electric buses KAMAZ electric, Drive, charging, Electro, electric bus, electric bus, "KAMAZ", this, electric buses, "KAMAZ", production, electric buses, see, transport, such companies, batteries, Toshiba

According to the technical task from Moscow, KAMAZ electric buses must travel at least 40 km on a single charge. At the same time, the entire fifteen-year cycle of servicing the electric batteries remains with the enterprise of Neftekamsk.
Photo 15.
How do electric buses KAMAZ electric, Drive, charging, Electro, electric bus, electric bus, "KAMAZ", this, electric buses, "KAMAZ", production, electric buses, see, transport, such companies, batteries, Toshiba

Photo 16.
How do electric buses KAMAZ electric, Drive, charging, Electro, electric bus, electric bus, "KAMAZ", this, electric buses, "KAMAZ", production, electric buses, see, transport, such companies, batteries, Toshiba

There is no usual rear axle in the electric bus! Instead, a special electroportal bridge with built-in motor-wheels was installed.Thanks to him, not only managed to resolve the issue with the transfer of energy from the electric motor to the wheels, but also to maintain the lowest possible floor even in the aft cabin. Thus, the electric bus turned out to be completely low-floor, which will undoubtedly be noted by both transport workers and passengers.
By the way, elektroportalny bridge bears the logo «ZF», which removes all the questions about his reliability and maintenance features.
Photo 17.
How do electric buses KAMAZ electric, Drive, charging, Electro, electric bus, electric bus, "KAMAZ", this, electric buses, "KAMAZ", production, electric buses, see, transport, such companies, batteries, Toshiba

When it comes to batteries or electric vehicles, the first thing comes to mind, with its winter low temperatures, aggressive aqueous medium and the duration of the charging.
The factory assured that these problems are resolved. The fact that electric buses KAMAZ applied to the battery pack lithium-titanate battery WM 17440 Company Drive Electro. He was tested for all peak indicators, and the main feature is the possibility of ultra-fast charging. The prefix "ultra" means that elektrobusa may charge the battery to 80% for 6-20 minutes, unlike the previous generation Fast-batteries, which require at least two hours for this purpose. In addition, the number of charge – discharge cycles now reaches 10,000 versus 3,000 earlier, which means thatOne more problem was removed - “burnout” of the battery when using the mode of accelerated charging and, as a result, its fragility.
Photo 18.
How do electric buses KAMAZ electric, Drive, charging, Electro, electric bus, electric bus, "KAMAZ", this, electric buses, "KAMAZ", production, electric buses, see, transport, such companies, batteries, Toshiba

Moreover, new batteries can operate in the range from –30 ° C to +45 ° C (using the temperature control system to –45 ° C), which removes the problem for year-round operation of electric buses in the northern regions of the country.
Photo 19.
How do electric buses KAMAZ electric, Drive, charging, Electro, electric bus, electric bus, "KAMAZ", this, electric buses, "KAMAZ", production, electric buses, see, transport, such companies, batteries, Toshiba

In practice, work on the line of the electric bus will not differ from that of a regular bus. KAMAZ-55994E is not tied to any power sources and can freely move along any city streets.
Photo 20.
How do electric buses KAMAZ electric, Drive, charging, Electro, electric bus, electric bus, "KAMAZ", this, electric buses, "KAMAZ", production, electric buses, see, transport, such companies, batteries, Toshiba

On routes with a leverage of up to 50 km, one ultrafast recharging station at the end station will suffice, if more, then another station will be needed.
Photo 21.
How do electric buses KAMAZ electric, Drive, charging, Electro, electric bus, electric bus, "KAMAZ", this, electric buses, "KAMAZ", production, electric buses, see, transport, such companies, batteries, Toshiba

I used to see it a little differently and I imagined that electric public transport should also have a large power reserve of hundreds of kilometers, as well as private passenger traffic. But apparently the possibility of ultrashort charging solves all the questions, but the routes are mostly not so long.
Photo 22.
How do electric buses KAMAZ electric, Drive, charging, Electro, electric bus, electric bus, "KAMAZ", this, electric buses, "KAMAZ", production, electric buses, see, transport, such companies, batteries, Toshiba

That's interesting, the tires are already with the logo "Mosgortrans"
Photo 23.
How do electric buses KAMAZ electric, Drive, charging, Electro, electric bus, electric bus, "KAMAZ", this, electric buses, "KAMAZ", production, electric buses, see, transport, such companies, batteries, Toshiba

Here is the "skeleton" of the electric bus inside.
Photo 24.
How do electric buses KAMAZ electric, Drive, charging, Electro, electric bus, electric bus, "KAMAZ", this, electric buses, "KAMAZ", production, electric buses, see, transport, such companies, batteries, Toshiba

Another unit from the already known company.
Photo 25.
How do electric buses KAMAZ electric, Drive, charging, Electro, electric bus, electric bus, "KAMAZ", this, electric buses, "KAMAZ", production, electric buses, see, transport, such companies, batteries, Toshiba

So, after the electrical equipment was installed and tested, the product again moves from the experimental electric bus workshop to the general assembly shop and continues its march along the conveyor.
Photo 26.
How do electric buses KAMAZ electric, Drive, charging, Electro, electric bus, electric bus, "KAMAZ", this, electric buses, "KAMAZ", production, electric buses, see, transport, such companies, batteries, Toshiba

Begin to attach the side panels and the insides of the cabin.
Photo 27.
How do electric buses KAMAZ electric, Drive, charging, Electro, electric bus, electric bus, "KAMAZ", this, electric buses, "KAMAZ", production, electric buses, see, transport, such companies, batteries, Toshiba

I want to note a serious cleanliness in the shops. I did not expect to see it in such a production. But as they say, this is a long-standing policy of the enterprise, even competitions are held with the awarding of the cleanest workshops of NEFAZA. Very good practice.
Photo 28.
How do electric buses KAMAZ electric, Drive, charging, Electro, electric bus, electric bus, "KAMAZ", this, electric buses, "KAMAZ", production, electric buses, see, transport, such companies, batteries, Toshiba

See how the floor glitters :-)
Photo 29.
How do electric buses KAMAZ electric, Drive, charging, Electro, electric bus, electric bus, "KAMAZ", this, electric buses, "KAMAZ", production, electric buses, see, transport, such companies, batteries, Toshiba

Photo 30.
How do electric buses KAMAZ electric, Drive, charging, Electro, electric bus, electric bus, "KAMAZ", this, electric buses, "KAMAZ", production, electric buses, see, transport, such companies, batteries, Toshiba

It was interesting to observe how the controllers begin to inspect the already-ready electric bus.
Photo 31.
How do electric buses KAMAZ electric, Drive, charging, Electro, electric bus, electric bus, "KAMAZ", this, electric buses, "KAMAZ", production, electric buses, see, transport, such companies, batteries, Toshiba

And now we have almost completely finished vehicle.
Photo 32.
How do electric buses KAMAZ electric, Drive, charging, Electro, electric bus, electric bus, "KAMAZ", this, electric buses, "KAMAZ", production, electric buses, see, transport, such companies, batteries, Toshiba

Usually each city orders its own color scheme. Kazan, for example, orders red buses, but Moscow ordered blue electric buses.
Photo 33.
How do electric buses KAMAZ electric, Drive, charging, Electro, electric bus, electric bus, "KAMAZ", this, electric buses, "KAMAZ", production, electric buses, see, transport, such companies, batteries, Toshiba

I recently chose a car and really wanted an electronic dashboard - I didn't pull it. And what my amazement was when I look in the KAMAZ electric bus - here it is! In public transport! We are used to the fact that in such vehicles everything is the simplest and “oak”.
Photo 34.
How do electric buses KAMAZ electric, Drive, charging, Electro, electric bus, electric bus, "KAMAZ", this, electric buses, "KAMAZ", production, electric buses, see, transport, such companies, batteries, Toshiba

Look what a beauty.
Photo 35.
How do electric buses KAMAZ electric, Drive, charging, Electro, electric bus, electric bus, "KAMAZ", this, electric buses, "KAMAZ", production, electric buses, see, transport, such companies, batteries, Toshiba

I, as an IT person, like that oh so much!
Photo 36.
How do electric buses KAMAZ electric, Drive, charging, Electro, electric bus, electric bus, "KAMAZ", this, electric buses, "KAMAZ", production, electric buses, see, transport, such companies, batteries, Toshiba

Instead of an internal combustion engine, an electroportal bridge ZF AVE130 is used with two asynchronous on-board geared motors of 125 kW each. In the engine compartment - a screw compressor, receivers and high-voltage inverters.
Photo 37.
How do electric buses KAMAZ electric, Drive, charging, Electro, electric bus, electric bus, "KAMAZ", this, electric buses, "KAMAZ", production, electric buses, see, transport, such companies, batteries, Toshiba

Other aggregate base of the electric bus in comparison with diesel or gas engines allows you to save well. It is much easier and cheaper to maintain the electric bus in operation: it has less frequent regular maintenance, there are no consumables, such as engine and transmission oils, and finally, the cost of electricity is about five times less than diesel with the same traffic volume. In the case of full-fledged operation per day, about 3 thousand rubles will be spent on electricity.
Photo 38.
How do electric buses KAMAZ electric, Drive, charging, Electro, electric bus, electric bus, "KAMAZ", this, electric buses, "KAMAZ", production, electric buses, see, transport, such companies, batteries, Toshiba

Charging ...
Photo 39.
How do electric buses KAMAZ electric, Drive, charging, Electro, electric bus, electric bus, "KAMAZ", this, electric buses, "KAMAZ", production, electric buses, see, transport, such companies, batteries, Toshiba

In general, there are a lot of electronic chips in the electric bus.
Photo 40.
How do electric buses KAMAZ electric, Drive, charging, Electro, electric bus, electric bus, "KAMAZ", this, electric buses, "KAMAZ", production, electric buses, see, transport, such companies, batteries, Toshiba

Camcorders as an external review ...
Photo 41.
How do electric buses KAMAZ electric, Drive, charging, Electro, electric bus, electric bus, "KAMAZ", this, electric buses, "KAMAZ", production, electric buses, see, transport, such companies, batteries, Toshiba

... so also internal. Several video cameras (note - with infrared illumination) is in the cabin.
Photo 42.
How do electric buses KAMAZ electric, Drive, charging, Electro, electric bus, electric bus, "KAMAZ", this, electric buses, "KAMAZ", production, electric buses, see, transport, such companies, batteries, Toshiba

Here is a comfortable driver's seat.
Photo 43.
How do electric buses KAMAZ electric, Drive, charging, Electro, electric bus, electric bus, "KAMAZ", this, electric buses, "KAMAZ", production, electric buses, see, transport, such companies, batteries, Toshiba

Checked out ...
Photo 44.
How do electric buses KAMAZ electric, Drive, charging, Electro, electric bus, electric bus, "KAMAZ", this, electric buses, "KAMAZ", production, electric buses, see, transport, such companies, batteries, Toshiba

And what do you think that is?
And this is a thermal curtain in front of each door. In winter there will be minimal heat loss in the cabin.
Photo 45.
How do electric buses KAMAZ electric, Drive, charging, Electro, electric bus, electric bus, "KAMAZ", this, electric buses, "KAMAZ", production, electric buses, see, transport, such companies, batteries, Toshiba

There is a button in front of the entrance to the middle doors of the electric bus. A passenger with disabilities clicks on her ...
Photo 46.
How do electric buses KAMAZ electric, Drive, charging, Electro, electric bus, electric bus, "KAMAZ", this, electric buses, "KAMAZ", production, electric buses, see, transport, such companies, batteries, Toshiba

...., the driver exits and lowers the ramp:
Photo 47.
How do electric buses KAMAZ electric, Drive, charging, Electro, electric bus, electric bus, "KAMAZ", this, electric buses, "KAMAZ", production, electric buses, see, transport, such companies, batteries, Toshiba

Landing at the stop occurs in the same manner.
Photo 48.
How do electric buses KAMAZ electric, Drive, charging, Electro, electric bus, electric bus, "KAMAZ", this, electric buses, "KAMAZ", production, electric buses, see, transport, such companies, batteries, Toshiba

On the video at the beginning of the post, you can see how we managed to take a ride on the electric bus around the plant - really quite a smooth and quiet ride.
Photo 49.
How do electric buses KAMAZ electric, Drive, charging, Electro, electric bus, electric bus, "KAMAZ", this, electric buses, "KAMAZ", production, electric buses, see, transport, such companies, batteries, Toshiba

As I already mentioned, there are a lot of electronic buttons in the cabin. Here even with Braille.
Photo 50.
How do electric buses KAMAZ electric, Drive, charging, Electro, electric bus, electric bus, "KAMAZ", this, electric buses, "KAMAZ", production, electric buses, see, transport, such companies, batteries, Toshiba

Nice floor lighting.
Photo 51.
How do electric buses KAMAZ electric, Drive, charging, Electro, electric bus, electric bus, "KAMAZ", this, electric buses, "KAMAZ", production, electric buses, see, transport, such companies, batteries, Toshiba

But the glass partitions at first caused some concern to me, but at the factory they were convinced that they had passed all the tests and the impact of an object of 80 kg. could not break it. Although to be honest, we have enough and bigger fools.
Photo 52.
How do electric buses KAMAZ electric, Drive, charging, Electro, electric bus, electric bus, "KAMAZ", this, electric buses, "KAMAZ", production, electric buses, see, transport, such companies, batteries, Toshiba

The interior of the passenger area is made in calm blue colors, and the floor is finished under the laminate - like many modern buses of European brands. In the area of ​​the seats are mounted several USB connectors for charging gadgets. The machine is adapted for citizens of limited mobility and passengers with prams: in the central part of the cabina spacious storage area is provided, and the middle door is equipped with a ramp.
Photo 53.
How do electric buses KAMAZ electric, Drive, charging, Electro, electric bus, electric bus, "KAMAZ", this, electric buses, "KAMAZ", production, electric buses, see, transport, such companies, batteries, Toshiba

But the representatives of the press met the General Director of PJSC "NEFAZ" Sergey G. Zuykov. It was interesting to look at the working biography of the head. Sergey Gennadievich began his labor activity at the Press-Frame Plant of PJSC KAMAZ after serving in the army as a mechanic of third-rate assembly work. In 2003, he became a master, and in 2004, he became a senior master in the PRZ workshop. In 2008, from the post of head of the welding shop for the bus chassis of the PRZ, he moved to the position of KAMAZ's main dispatcher, and later, deputy director of the KAMAZ production management department. From 2014, he worked as director of the Repair and Tool Plant of PJSC KAMAZ (two years before that he was the chief engineer). That's as they say "from the bottom" :-)
Photo 54.
How do electric buses KAMAZ electric, Drive, charging, Electro, electric bus, electric bus, "KAMAZ", this, electric buses, "KAMAZ", production, electric buses, see, transport, such companies, batteries, Toshiba

Sergey was asked about the difficulties and prospects of production. He categorically did not want to talk about difficulties, but he sees great prospects in terms of production of electric buses.
Photo 55.
How do electric buses KAMAZ electric, Drive, charging, Electro, electric bus, electric bus, "KAMAZ", this, electric buses, "KAMAZ", production, electric buses, see, transport, such companies, batteries, Toshiba

I was pleased to talk about the product of the enterprise and all the time I was trying to show myself in the electric bus what we had not yet considered.
Photo 56.
How do electric buses KAMAZ electric, Drive, charging, Electro, electric bus, electric bus, "KAMAZ", this, electric buses, "KAMAZ", production, electric buses, see, transport, such companies, batteries, Toshiba

In general, we are moving forward from Neftekamsk to Bibirevo :-)
Photo 57.
How do electric buses KAMAZ electric, Drive, charging, Electro, electric bus, electric bus, "KAMAZ", this, electric buses, "KAMAZ", production, electric buses, see, transport, such companies, batteries, Toshiba

So what else to tell. And, well, we forgot about such a process, for example, as the recovery mode. But according to the driver, at a 900-meter congress, from a turning overpass, about 2-3% charge can be returned to the drives, which in fact is not so little.
Photo 58.
How do electric buses KAMAZ electric, Drive, charging, Electro, electric bus, electric bus, "KAMAZ", this, electric buses, "KAMAZ", production, electric buses, see, transport, such companies, batteries, Toshiba

Photo 59.
How do electric buses KAMAZ electric, Drive, charging, Electro, electric bus, electric bus, "KAMAZ", this, electric buses, "KAMAZ", production, electric buses, see, transport, such companies, batteries, Toshiba

Those drivers who were on test flights and managed these electric buses speak very well of them. There was practically no need to retrain; the electric maneuverability of the electric bus is excellent, independent front suspension and a very comfortable and modern workplace for the driver.
Photo 60.
How do electric buses KAMAZ electric, Drive, charging, Electro, electric bus, electric bus, "KAMAZ", this, electric buses, "KAMAZ", production, electric buses, see, transport, such companies, batteries, Toshiba

Moscow electric bus is one hundred percent environmentally friendly form of transport. They have passengers waiting for climate control, Wi-Fi, USB-connectors for charging mobile devices and a low floor.
Thanks to electric buses, it will be possible to reduce operating costs (compared to trolley buses, operating a new type of transport is 10 percent cheaper), simplifies maintenance of rolling stock (service life - 15 years on service terms), reduces harmful emissions, reduces noise and vibration in the cabin. by 30 percent compared to buses.
Photo 61.
How do electric buses KAMAZ electric, Drive, charging, Electro, electric bus, electric bus, "KAMAZ", this, electric buses, "KAMAZ", production, electric buses, see, transport, such companies, batteries, Toshiba

By 2020, Moscow plans to purchase 900 electric buses.
Photo 62.
How do electric buses KAMAZ electric, Drive, charging, Electro, electric bus, electric bus, "KAMAZ", this, electric buses, "KAMAZ", production, electric buses, see, transport, such companies, batteries, Toshiba

P.S. It is interesting to observe in the Russian regions inscriptions in national languages. Not familiar to a resident of Central Russia, but reminds us of how large and multinational our country is.
Photo 63.

Related news

How do electric buses KAMAZ image, picture How do electric buses KAMAZ How do electric buses KAMAZ How do electric buses KAMAZ How do electric buses KAMAZ How do electric buses KAMAZ How do electric buses KAMAZ How do electric buses KAMAZ How do electric buses KAMAZ How do electric buses KAMAZ How do electric buses KAMAZ How do electric buses KAMAZ How do electric buses KAMAZ How do electric buses KAMAZ How do electric buses KAMAZ How do electric buses KAMAZ How do electric buses KAMAZ How do electric buses KAMAZ How do electric buses KAMAZ How do electric buses KAMAZ How do electric buses KAMAZ How do electric buses KAMAZ How do electric buses KAMAZ How do electric buses KAMAZ How do electric buses KAMAZ