A pure electric vehicle with an acceleration score of "4S/0S/0S" can always give people a suffocating sense of acceleration, but in addition to accelerating fast enough in a straight line, why does it still feel that something is missing in other control scenarios?
What's missing?
Some netizens think that it is a lack of control.
However, the sense of control is a feeling in the clouds and fog, which is difficult to describe clearly in words or words; Therefore, some readers and friends would like to be able to talk about this topic. From the perspective of "wire control", the author does not deny that some electric vehicles do lack a sense of driving or control, and the reason is that the full mechanical structure has gradually evolved into a full drive-by-wire drive platform.
The concept of line control:
In the electromechanical industry, the term "wire control" is used in the terminology, and its concept is the connection between the "signal generator" and the "signal receiver"; It's not the mechanics that connect the two, it's the cables, but the cables don't connect, drive, or control – they don't "pull the wires." "Its role is to transmit electrical signals.
The full wire control is the same for the car, and the current car accelerator pedal is electronic, which is a typical wire control system; The accelerator pedal or electric pedal is not connected to the engine throttle or electronic control system at all by a cable or connecting rod, and the pedal itself can be understood as a "resistance regulator." "The pedal is actually adjusting the resistor, and then the signal is transmitted to the control unit (microcomputer) through changing currents and cables; Finally, the control unit analyzes the output signal based on the electrical signal, and then controls the throttle or the electronic control system to adjust the output power.
Some drivers feel that the current car throttle "doesn't follow." ”
This is not an illusion but an objective fact, once the mechanical throttle was directly connected to the throttle of the engine; When the throttle touches a little, the throttle opening will be increased a little, and the two are completely synchronized, so there is no lag in action and feedback. The electronic throttle needs to analyze the calculation process, and some system settings will also deliberately set the hysteresis reaction time, so there is a situation of "the throttle does not follow".
The steering wheel steering feel is also changing, and the reason is that some electric vehicles now use "steer-by-wire". ”
In the past, the steering gear of automobiles was mechanical, and the steering column connected to the steering wheel directly controlled the steering machine; If the steering wheel turns a little bit, the guide wheel will follow a little bit – but that doesn't matter. Because the "steer-by-wire machine" can also achieve high-efficiency synchronous steering through high-efficiency signal transmission! However, the steering wheel of this steering wheel is only connected to the steering machine by cables, and there is no mechanical coupling between the two, so any undulating impact of the guide wheel cannot be fed back to the steering wheel.
On the contrary, whether it is hydraulic power, electric power, or electro-hydraulic power steering; It is mechanically coupled with the steering machine through the mechanical structure, so that the steering wheel can be intuitively fed back to the steering wheel held by the mechanical structure if there is a little undulating impact.
This feeling is difficult to simulate clearly, so the "steer-by-wire machine" really lacks a sense of mechanical control.
Conventional rear-wheel drive or all-wheel drive systems are mechanically coupled, connected by transmission, transfer case, transmission shaft, differential; There are some changes in the driving state of the wheels, which can actually be fed back into the intuitive working experience to a certain extent. The current electric rear-wheel drive is rear-mounted rear-wheel drive and does not have a transmission; The four-wheel drive system is composed of non-mechanical coupling of the front and rear motors, and the control experience will be very different from that of fuel vehicles.
Real veteran drivers always start with fuel vehicles, so it is naturally difficult to adapt to using this "full drive-by-wire" electric or hybrid car.
However, high-performance cars need to be fed back to the driver through the mechanical structure to change every detail, so high-performance cars with high playability must be fuel vehicles; This is also one of the reasons why the founders of some well-known automobile companies who are keen to build new energy vehicles will still buy or keep some fuel vehicles.
There are two other drawbacks to the "full drive-by-wire" drive concept.
The first disadvantage is that the maintenance cost of the vehicle is high in the later stage, and the vehicle uses too many chips, and even the automotive-grade chips will inevitably age. The chip design service life of this standard is generally 15 years, which is three times that of ordinary consumer-grade chips, and 0 years longer than the service life of industrial-grade chips! It seems that the service life is long enough. But not everyone's car has to be scrapped at 0. And will there be a huge difference between the design service life and the real service life? At least I don't dare to make any guarantees to my readers.
The second disadvantage is that the reliability is not as high as the mechanical structure.
Assuming that the steer-by-wire chip platform fails, the vehicle will not be able to steer; Even if the power assist system is damaged, the steering wheel can be forcibly steered, otherwise, the steer-by-wire can only be rotated to play.
To sum up, a fully wire-controlled car is like playing a racing game, and the equipment that can be used in the car is actually the concept of "controller"; It's like playing Super Mario with a controller, how can you possibly feel Mario jumping up? The mechanical structure is like wearing a smart device, which can be intuitively felt when moving and still, which is the biggest difference between the two.
As for the understanding of vehicle safety redundancy, it can only be said that there are different opinions.
Leaving everything to the chip is more like complicating simple things, and this drive scheme is only suitable for ordinary passenger cars at best; Off-road vehicles, trucks, and special vehicles used outdoors are still more suitable for mechanical systems that retain key assemblies and structures.