From the implementation of the first national standard to the implementation of the sixth national standard, it took China less than 20 years. On average, the emission standards were updated in less than 4 years of vehicle torque limiting.
In order to meet the increasingly stringent emission requirements, our truck engines have also changed from self-priming mechanical oil supply to electronically controlled common rail to the current SCR, DOC and DPF. In the post-processing system, there are many new technologies stuffed into it. At the same time, the problems brought by them are also frequent of vehicle torque limiting ehicle torque limiting.
In the forum, I searched the keyword “limited torsion” for nearly a year and found 5087 results. No matter which car company’s truck, it has similar faults of vehicle torque limiting.
So what is the reason for the limited torque of the vehicle? Is it the poor quality of the vehicle? The manufacturer pulled out the semi-finished products and sold them, or did his own operation method be wrong? Today, on the truck encyclopedia, let’s talk about those “Postures” that cause vehicle torque limitation of limiting poor quality ehicle torque limiting .
There are two forms of restriction: primary driving performance restriction system (engine performance restriction) and severe driving performance restriction system (effective restriction of vehicle operation) of vehicle torque limiting.
Under what circumstances will the vehicle diagnostic system limit the vehicle performance? Here we talk about the primary driving performance restriction system separately from the severe driving performance restriction system of limiting poor quality ehicle torque limiting .
The primary driving performance limit system (hereinafter referred to as the primary limit) has relatively soft performance limits on the vehicle. It only limits the torque of the vehicle, and the limit range is 75% of the external characteristic torque of the engine. If your vehicle torque is 2600 nm, give a 75% discount, and you can still have 1950 nm of torque left of limiting poor quality of vehicle torque limiting .
Of course, there are many cases that trigger the primary limiting system. According to the provisions of gb17691-2018, 75% of the torque limiting system will be triggered in the following six cases limiting poor quality of ehicle torque limiting .
1. If the residual amount of reagent (urea) is lower than 2.5% of the rated capacity or the minimum value set by the vehicle manufacturer, activate the primary limit of vehicle torque limiting.
2. If the quality of reagent (urea) is not up to standard or the urea concentration is lower than the lower limit and lasts for more than 10 hours, the primary limit is activated of vehicle torque limiting.
3. If the deviation between the consumption of reagent (urea) and the actual demand exceeds 50% and the duration exceeds 10 hours, the primary limit is activated of ehicle torque limiting.
4. The injection of reagent (urea) nozzle is interrupted unexpectedly and lasts for more than 10 hours, and the primary limit is activated of vehicle torque limiting.
5. The EGR valve is stuck for more than 36 hours, and the primary limit is activated of vehicle torque limiting.
6. The tamper proof detection system (post-processing monitoring, including various post-processing sensors, circuits, etc.) fails and lasts for more than 36 hours, activating the primary limit.
It’s also relatively simple to eliminate the primary restrictions. Throw away the parts that we can’t repair by ourselves, add enough urea for lack of urea, and replace those with inferior urea quickly, which can basically restore the vehicle to normal torque. If the problem is caused by stuck valve, damaged sensor and failure, find the service station as soon as possible to avoid affecting the operation of ehicle torque limiting.
However, if the driver continues driving forcibly regardless of the vehicle’s warning, the vehicle will activate the severe driving performance restriction system (hereinafter referred to as severe restriction), control the vehicle speed at 20km / h, and the vehicle will enter the limp mode. At this time, unless you completely eliminate the following problems, the vehicle will always be in the limp mode of ehicle torque limiting.
1. When the urea tank is empty, the urea injection system cannot continue to inject urea, or the urea solvent is lower than the lower limit specified by the automobile manufacturer, which seriously limits the activation of vehicle torque limiting.
2. If the quality of reagent (urea) does not meet the standard or the urea concentration is lower than the lower limit and lasts for more than 20 hours, the severe limit will be activated of vehicle torque limiting.
3. The deviation between the consumption of reactant (urea) and the actual demand exceeds 50%, and the duration exceeds 20 hours, so the activation is seriously limited of vehicle torque limiting.
4. The injection of reagent (urea) nozzle was interrupted unexpectedly for more than 20 hours, and the severe limit was activated of vehicle torque limiting.
5. EGR valve is stuck and lasts for more than 100 hours, activating severe limit of vehicle torque limiting.
6. Tamper proof detection system (post-processing monitoring, including all kinds of post-processing sensors, circuits, etc.) fails and lasts for more than 100 hours, with serious restrictions on activation of vehicle torque limiting.
In addition to the above performance limits, the vehicle also carries out real-time monitoring on the emission of the afterprocessor. If the sensor detects that the purification performance of the afterprocessor such as DPF, SCR, LNT and TWC exceeds the limit and lasts for more than 100 hours, the severe limit will also be activated limiting poor quality of vehicle torque limiting .
Through the above interpretation of gb17691-2018, I believe you have a basic understanding of vehicle torque limit and why. In fact, according to the author’s understanding, most of the torque limit of guoliu truck are accidental faults. Because card friends do not add urea in time, or add cheap urea and diesel, it will lead to vehicle torque limit. After replacing the compliant urea and fuel, the torque limiting fault can be basically eliminated by itself limiting poor quality .
t’s not terrible to limit torsion. What’s terrible is the thinking of keeping a car that you don’t want to keep up. Torque limitation is not a quality problem of manufacturers. Torque limitation is only a rational move of the state to protect the ecological environment and reduce carbon emissions of ehicle torque limiting.
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