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Electric cars are quickly becoming popular, especially in Europe. So, since I was at the Paris Motor Show this week, I thought I would walk around, look at all the electrified powertrain technologies (focusing on sectional displays), and that I would talk to the engineers about what we can expect from the cars of the near future.
I said it a hundred times probably, but it's worth repeating: Basically, the true technical innovation in the automotive industry usually occurs at the supplier level. Most of the people I spoke to in Paris were companies that do not sell products to our consumers, but to car manufacturers.
But before I get to the vendors' booths, I have to show you this nice Jaguar I-Pace chassis, because who would I be if I refused you this pleasure for the eyes? I would be a monster, that's who.
The best part of the model, in addition to all that, is the cooling system. Mainly because I am in cooling systems, but also because it's enough to look where this cooling pipe routes:
It goes from the front of the car, just above the engine, into the wheel well behind the place where the wing is and backwards through the rocker. It's a weird package, but I'm part of it.
In the picture below, taken from the back, you can see that the blue pipe goes back to a box just above the rear engine (I suppose it's an inverter):
Take a closer look via a Jaguar press photo (notice the blue pipe coming from the passenger side, there):
In the photo below, you also see what looks like a high voltage compressor (this big silver cylinder located at the bottom of the unit .It looks like an AC compressor of a car with internal combustion engine , which tends to be powered by the accessory (drive), whose job is not only to perform HVAC functions for cabin comfort, but also to maintain cold cells as part of a 'cooler' From refrigerant to refrigerant.
Normally, the I-Pace simply uses passive cooling via an upstream radiator, but when the cell temperature is too high, the cooler cools the coolant and thus the cells.
Speaking of cells, there are 432, and they are of the variety in pocket:
Here is the closest look that I could get:
Acting batteries, the leading French automaker Faurecia, but which has offices everywhere, including in Auburn Hills, Michigan, has introduced its composite battery concept in place of aluminum. (used by many car manufacturers).
According to Guillaume Chambon, who is responsible for Faurecia's range of battery products for composite technologies, a six-millimeter lower cover can offer the same resistance and a 50% weight gain compared to a lower aluminum cover of the same thickness.
In addition, the company claims that the insulating property of the composite material allows for more efficient thermal regulation, since almost all of the cooling will act on the cells rather than on the outside environment. Here is an overview of the cooling system:
This cooling circuit is under an aluminum plate, which interacts with the vertical aluminum plates between the cells to ensure the transfer of heat from the cell to the coolant.
Take a closer look at the small space where the coolant flows under this flat aluminum heating plate:
Notice the presence of aluminum bundles between the left cells in the image above. these are there for the protection against accidents, it was said. With regard to the protection against shock from underneath, Faurecia claims that the composite bottom cover (which contains a certain amount of kevlar) deviates much less when it is exposed to a high load than a aluminum battery pack used by Tesla.
(Of course, I can not confirm this, it's based on what a representative told me about the auto show, and of course it's a sales pitch to the automakers here, so a grain of salt and all that.)
Chambon also mentioned the electromagnetic shielding, which essentially requires an aluminum foil on the top cover (although other solutions are apparently under development), and another integrated solution in the composite bottom cover, maybe some sort of wire mesh.
Faurecia also brought a fuel cell technology to the party in Paris. Specifically, they installed the two above-mentioned hydrogen fuel tanks, developed with STELIA Aerospace Composites and composed of three layers. Starting with the interior, there is plastic (probably to help seal), then carbon fiber (for the structure), then fiberglass to protect the carbon fiber.
Faurecia believes that hydrogen fuel cells will take off in the future, given the weaknesses in weight, battery life and charging time of battery electric cars. Apparently, the new tanks can be refilled in just three to five minutes and they are light. The representative told me that the 700 – bar tanks could hold seven kilograms of hydrogen per 100 kilograms of mass of an empty tank (the total tank capacity of these tanks is six kilograms). Normally in the industry, he said, a 100 kilogram tank tends to contain only five kilograms of hydrogen.
The machines you see at the end of the tanks include mechanical safety valves, which, he tells me, react to the temperature (not the pressure) and release hydrogen into the environment if necessary. The valves are also able to indicate if there is a leak in the system and will stop the flow to the fuel cell accordingly.
The flow will also be limited by the service station. In the above picture, you can see where the fill point is. It looks like a small pole standing behind the wheel. A gas station will be connected and will communicate with the car to make sure there is no problem of overheating.
However, before arriving at the hydrogen fuel cell stack, hydrogen flows from the tanks via this gear, which drops the pressure from 700 to 10 bar.
From there, the hydrogen goes to the 100 kW fuel cell, where the hydrogen ions pass through a catalyst, lose electrons (which pass through a wire to generate electricity), and then end up combining with oxygen and electrons to form water. Here is a preview of this stack:
At the rear is a small battery pack that powers the accessories, recovers energy during braking, and eventually powers the wheels in high-demand situations. The spokesman pointed out that the battery could also power the vehicle itself, in which case the vehicle would act as a plug-in hybrid, the fuel cell acting as an extension of autonomy.
I then headed to Aisin, a major Japanese supplier known primarily for transmissions, but part of a larger group, the "Aisin Group", which manufactures all kinds of automotive components.
These include braking systems, such as the "Cooperative Braking System with Energy Recovery" shown below, manufactured by Advics of the Aisin Group and used in the Toyota Prius.
It is a cable braking system consisting of an active left-hand hydraulic servomotor and an "active power supply", an electric pump and a hydraulic accumulator for storing high pressure. right.
The fundamental purpose of the system is to ensure a smooth and predictable pedal feel, even when the vehicle's electric motor creates a drag in its regenerative braking process. Advics describes the main benefit of the system:
An electronically controlled braking system is a control system in hybrid vehicles, etc., which uses the power of hydraulic braking and the power regenerative braking power in a coordinated manner, so that the kinetic energy is recovered during deceleration in the most efficient way. A flawless stay
My rudimentary understanding, based on a short discussion with an engineer, is that it works like this:
The driver presses on the brake pedal, which pushes the rod marked "1" above.It sends the fluid in the "2", which looks like a cylindrical chamber.It is here that the pedal stroke is measured by This information indicates the driver presses the pedal, as well as the status of the regenerative braking (ie how much the engine is slowing down the vehicle), the calculator ("0" above) calculates the amount of friction braking to apply.
As I understand it, the system applies the brakes by strategically opening the "3" valves powered by the pump / accumulator. By opening the valves, the piston marked "4" is expelled, which creates a pressure in the hydraulic braking system.
The representative told me that it could happen that the driver presses on the brake pedal, but that the standard friction brakes do not activate at all. On the contrary, regenerative braking is able to give the appropriate deceleration.
The man on the stand also told me that there was built-in security. In the event of an electrical failure, it would appear that a valve on "2" closes, directing the fluid directly to the master cylinder and creating a brake pressure.
A series of electric pumps was also exposed at Aisin. I will not dwell on it because I realize that the pumps are not sexy. But it should be mentioned, because as cars become more and more electrified or engine stop systems continue to proliferate in the industry, electric pumps will become more important.
If you are driving a regular internal combustion engine vehicle, there is a good chance that your engine coolant will be circulating through a water pump on your accessory drive or on a timing belt / chain, and There is also a good chance that the fluid in your transmission will move the pump internally.
Electric cars do not have accessory belts, so almost all the coolant or oil that powers the batteries, engines, gearboxes, power electronics or cockpit must go through electric pumps. Here are two examples (the "snails" red and blue at the bottom of the image) in the I-Pace above:
Even non-electrified cars with start / stop of the engine need an additional electric pump because maintaining the pressure of the pipeline in an automatic transmission is usually provided by an oil pump in the rotating box that is rotated by the engine, which is turned off during shutdown events. Daimler, in an old 2010 press release on start / stop, describes this need:
Electric transmission oil pump feeds the clutches of the automatic transmission with the oil pressure before starting, to allow a quick recovery of the course after the direct start of the combustion engine via ECO start / stop function
When the engine is stopped during a stop, water will not flow into the engine or HVAC system, which could compromise cabin heating and require an electric pump.
In addition, as fuel economy regulations become tighter, automakers are looking for ways to increase efficiency, and electric pumps can be turned on and off depending on the demand, while mechanical pumps tend to constantly circulate the fluid. There are some variable mechanical pumps, but they are not as precise.
Aisin also showed electric motors, including the 50 kW four-wheel drive introduced above. It's basically an engine built into a gearbox (I do not remember if it's oil or water, but you can see the two ports on the left in the picture above ). It is designed to be placed at the rear of a vehicle to assist conventionally driven front wheels when necessary, although Aisin says that it can fuel the vehicle alone, claiming that this eAxle is designed to convert a normal ICE car. in a plug-in hybrid.
Next to this four-wheel drive unit was the 100 kW electric drive unit that you see above. Its inverter rests on the top, which means that it is probably a front transmission unit, while one of the rear converters can have its inverter on the side, because the vertical packaging space located under the rear floor tends to be limited.
Speaking of packaging space, Aisin builds its gearboxes for these electric vehicles in the form of planetary reductions or parallel reductions, the first having the output shaft aligned with the motor (shorter overall design but perhaps larger), and the second offset but parallel the engine (a longer design, but possibly flatter).
One interesting thing about this training unit was an Aisin Tidbit team leader in electrical and hybrid systems, said Takuro Iwase. He stated that the eAxle system above incorporates a dual cooling system in which the coolant ("water") is used to maintain low variator temperatures, as well as the temperature of certain engine parts (at the same time). 39, outside of the stator if correctly recall). However, other internal components, such as the rotor and gearbox, are also cooled, but not by coolant – the coolant in a gearbox is not a good idea – but by the oil.
This oil in the gearbox captures heat from various components and loses it via an oil-water heat exchanger (not shown).
The dual cooling system is different from that used in the 150 kW cylinder illustrated above, in which the engine and the gearbox are both oil cooled. I was told that this purely oil-cooled configuration allowed for more precise control of the oil temperature, but it was not quite designed for suitcases as heavy as liquid-cooled design or by oil.
So yes, that's what I spent most of the day yesterday walking around looking for computer equipment and talking to the most naive people I could find. What is the purpose of car shows, right?
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