Product technical route
DPF (Diesel Particulate Filter) diesel particulate trap (also known as DPF tail gas post-processing system), after a long time of particulate trapping, will block the porous media channel of the filter, resulting in the back pressure rise in the exhaust system, and then affect the normal operation of the engine. Therefore, measures need to be taken to remove soot particles filtered by DPF and restore the filtering capacity of DPF. This method is called regeneration. Regeneration methods are generally divided into active regeneration and passive regeneration.
The products developed by Zhongzi Company are to reduce the emission of CO, HC and other pollutants in exhaust gas through DOC catalytic oxidation reaction. At the same time, DOC oxidizes NO in exhaust gas to NO2. Under appropriate temperature conditions, CDPF (a catalyst coated on DPF carrier, namely CDPF) can capture PM passively and regenerate PM. When the condition of active regeneration is reached, the control unit controls the injection device to inject fuel before DOC, and uses DOC to raise the exhaust temperature substantially, so that PM in CDPF can be burned and regenerated. The catalytic performance of DOC and the filtration performance of CDPF make the tail gas purified.
The company's products are tested according to the Ministry of Ecology and Environmental Protection test standards and industry test standards (HJ451-2008). The conversion efficiency of DOC to HC and CO is more than 80%, the capture efficiency of DPF to particulate matter is more than 90%, and the regeneration efficiency of particulate matter is more than 90%.
The control unit monitors the temperature of the catalyst and the pressure difference before and after CDPF, and judges whether regeneration is needed according to the carbo
n load and working conditions. If regeneration is needed, the controller will control the active regeneration system and have a remote online monitoring device.
(Revamping product sketch)
In view of the actual situation of diesel vehicle emissions in use, considering the longitude and latitude of different regions and the environmental temperature in winter, Zhongzi Environmental Protection provides two different transformation schemes, the main difference is that the regeneration technology routes are different to meet the transformation requirements of different vehicles.
The self-made products can be adapted to the five-stage automotive diesel oil in China (sulfur content S < 10ppm)
Product Safety Requirements
Remove the muffler of the original vehicle, install the product on the exhaust manifold of the engine, and fix it on the frame of the vehicle. On the premise of ensuring the installation space of catalytic muffler, the distance from the engine should be as short as possible. If necessary, the exhaust pipeline should be heat preserved, and the maximum distance after heat preservation should not exceed 2000 mm.
After the installation of the product, it ensures that the original safety performance of the vehicle is not changed and meets the relevant safety regulations. In view of the safety of the system control strategy, in some special circumstances and occasions, the control system will forcibly terminate the active regeneration of the product. Including: stop active regeneration process after parking, in special occasions (such as gas stations, inflammable and explosive places, etc.).
(2) Structural security
All products and accessories such as mounting brackets are made of materials that meet the strength requirements of the whole vehicle to prevent products from breaking and falling off due to severe vibration during driving. The structure and size are similar to the original muffler, which will not affect the original safety performance of the vehicle. Good thermal insulation measures to prevent fire or burns caused by high temperature.
(3) Security of control strategy
Accurate regeneration condition judgment ensures timely and effective regeneration of products. Set strict regeneration conditions threshold, including vehicle speed, exhaust temperature, CDPF back pressure, cumulative running time to reach the set value before regeneration, after parking or in special occasions (such as gas stations, flammable and explosive places) to force the termination of active regeneration.
The power is collected from the spare terminal of the original vehicle, and the system automatically loses power after parking, without affecting the electric system of the vehicle. With its own air source, the system does not need to take air from the original vehicle, and does not affect the braking performance of the vehicle.
Burner Type of DPF Tail Gas Post-treatment System
The burner type of DPF tail gas post-treatment system adopts the scheme of active + passive combined regeneration burner. The passive regeneration scheme is the same as the passive type of DPF tail gas post-treatment system, which is not discussed here. The burner ignition regeneration system detects soot load in CDPF by working time (e.g. 8 hours in a row)+pressure difference, triggers active regeneration. By controlling fuel injection, air intake and ignition plug, the controller burns the fuel injected in the burner and raises exhaust tail gas temperature rapidly, so that the temperature at the entrance of CDPF can reach more than 500 C, thus realizing active regeneration of CDPF.
The system chooses suitable operating conditions for regeneration, adopts closed-loop control, monitors the temperature of DOC front and rear ends, controls fuel injection and air volume, ensures regeneration temperature, and avoids regeneration runaway damage to CDPF carrier.
Similarly: 1. Passive DPF tail gas post-processing system
As can be seen from the above figure, the regeneration conditions of the system products are as follows: the regeneration of the burner can be realized under the medium exhaust flow rate and the temperature is less than 300 C.
Active Regeneration Device Structure
Regeneration Control Strategy
The burner ignition regeneration system detects soot load in CDPF by working time (e.g. 8 hours in a row)+pressure difference, triggers active regeneration. By controlling fuel injection, air intake and ignition plug, the controller burns the fuel injected in the burner and raises exhaust tail gas temperature rapidly, so that the temperature at the entrance of CDPF can reach more than 500 C, thus realizing active regeneration of CDPF.
Thermal management scheme
Same: DPF tail gas post-processing system passive type
Product physical drawing