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author | he xuyang

editor | andy tang

the "one-pedal" car is saved!

at the end of may this year, the ministry of industry and information technology drafted a "method" that specifically stipulates single pedals:

the popular understanding is that the single pedal mode may be banned.

one pedal is one of tesla's famous stunts.

on june 4, tesla responded to the "method" on its official website, saying that the relevant standards of the ministry of industry and information technology "have not yet been officially released and implemented, and will not affect tesla's existing products and functions."

after the draft "method" was released for comments, there was a lot of controversy on the internet. those who support the "method" believe that single pedals are the "culprit" in car accidents and should be banned.

opponents believe that a single pedal can recycle kinetic energy and increase mileage, which is a good feature.

in order to balance the opinions of all parties, the ministry of industry and information technology once again publicly solicited opinions on the "method" on september 20, and made new adjustments to the regulations prohibiting complete braking with one pedal.

judging from the regulations, the ministry of industry and information technology has relaxed the regulations on single-pedal complete braking, picking up the "single-pedal" regulations that were swept into the trash.

this time the car owner who is used to the single-pedal mode laughed. many car companies that use the single-pedal mode, such as ideal, nio, and polestar, also breathed a sigh of relief.

the file is a bit complicated, that’s okay, let’s start with what a single pedal is.

“anti-human” single-pedal design

what we call "single pedal" mode does not mean that the car has only one pedal. it also has two pedals: brake and accelerator (electric door).

in single-pedal mode, stepping on the accelerator will accelerate; slightly releasing the accelerator will decelerate; completely releasing the accelerator will decelerate to a stop; and pressing the brake will decelerate and stop.

one accelerator has so many functions, which leads many experienced drivers to drive without caring about the brake pedal. they only need to press and lift the accelerator, which is very convenient.

another benefit of a single pedal is that it can implement "kinetic energy recovery".

once the driver releases the accelerator pedal, the vehicle will drag the drive motor in the opposite direction under the action of inertia. the reverse torque of the motor during drag will decelerate the vehicle. at the same time, the motor will also generate current to charge the battery.

therefore, in the single-pedal mode, the car can also transform into a "slope engine" when going downhill, using the slope to charge, which is very environmentally friendly.

at the same time, because mechanical brake pads are used less, maintenance costs are also reduced.

because of these benefits, a number of new car companies such as nio, polestar, and ideal have also launched single-pedal models.

however, the shortcomings of single-pedal mode are also fatal.

since we usually use gasoline trucks in driving schools, we are used to stepping on the accelerator to accelerate and the brakes to slow down.

now suppose you are driving a tram in single-pedal mode. when you encounter an emergency and need to brake, should you lift your foot to brake or press your foot to brake?

when people encounter an emergency, their muscles are often tense, and it is unscientific to release the pedal at this time; and after training in driving schools, most people's subconscious mind is to slam on the pedal to brake in an emergency.

at this time, it is very likely that the wrong switch will be stepped on, causing the speed to increase sharply.

or during one or two moments when you were still struggling, the car had already sped off, causing a traffic accident.

many people have raised concerns about this: "if everyone uses a single pedal, won't their driver's license have to be retaken?"

to this end, the ministry of industry and information technology launched the mandatory national standard "technical requirements and test methods for passenger car braking systems" in may this year, which stipulates:

to put it bluntly, under the new regulations, the vehicle can still slow down after releasing the switch, but it cannot stop. if you want to stop, you must press the brake pedal.

this avoids the trap of using both pedals to brake, forcing everyone to step on the brakes every time they stop, and remember to change feet to slow down, reducing the possibility of stepping on the wrong pedal in an unexpected situation.

safe, but not one size fits all

such a regulation will definitely improve the safety factor of vehicle driving, but other car owners who find single pedals useful are not happy. people have been driving single-pedal cars for several years, and the brakes may no longer work.

especially during morning and evening peak hours, the benefits of a single pedal can be maximized: the driver does not need to switch pedals left and right, but only needs to adjust his right foot to follow the car in front.

moreover, the current single pedal is like a pit, and anything can be thrown into it. attributing all traffic accidents to single pedals is unfair to car companies that use single pedals.

therefore, this adjustment was made:

compared with the first version, the second version adds the expression "default working state" and changes "the vehicle cannot be decelerated to a stop" to "the vehicle should not be decelerated to a stop".

to put it bluntly, in the default state, the car cannot stop simply by releasing the accelerator pedal.

however, car owners who are accustomed to a single pedal can still manually set a specific working state to achieve the effect of braking when the accelerator pedal is released.

such regulations are like leaving a "back door" for single-pedal owners to avoid "one size fits all" while ensuring safety and prohibiting all single-pedal modes.

in addition, when the single-pedal mode is turned on, there must be an obvious "optical signal" to inform the car owner that the car is in a state where the pedal can be braked by releasing the pedal to prevent the car owner from misoperation.

finally, regarding brake lights, the ministry of industry and information technology has also made regulations. for vehicles in single-pedal mode, the brake light will not come on because the owner only needs to slightly release the accelerator pedal when decelerating and does not need to depress the brake pedal.

however, some models now only slightly release the pedal, which will produce a large braking deceleration. if the brake light is still off, it is easy for the vehicle behind to make a misjudgment and cause a rear-end collision.

therefore, the ministry of industry and information technology stipulates that when a vehicle experiences a large deceleration, the brake lights need to be illuminated to alert the vehicles behind and other traffic participants; and, after the brake signal is sent, the signal should continue to be sent as long as the need for deceleration continues.

you can also recover kinetic energy by applying the brakes

however, a new technology - the series regenerative braking system (crbs) - has emerged, which not only gets rid of the single-pedal braking trap, but also can regenerate electricity when braking, taking into account both.

crbs coordinates the work of two braking systems (electric regenerative braking and conventional hydraulic braking) through the vehicle's brake distribution system.

simply put, when the vehicle is driving at low speed or the driver decelerates slightly, the crbs system will give priority to using the reverse rotation of the motor to slow down, allowing the vehicle to gradually stop while recovering kinetic energy.

in this way, the brake pads are not subject to wear and the vehicle can recover some of its energy.

when the driver brakes urgently or decelerates quickly at high speed, the crbs system will quickly introduce the traditional hydraulic braking system, while regenerative braking will continue to work.

hydraulic brakes provide most of the braking force, ensuring the vehicle comes to a stop in the shortest possible time, while the electric motor continues to recover energy for more efficient braking.

currently, xpeng g9, bmw i3, byd dolphin and other models have used crbs technology.

maybe in a while, safer crbs technology will be popularized, and traffic accidents caused by single pedals will be greatly reduced.