KR100795033B1 - Regeneration logic of only doc system for disel automobile - Google Patents

Abstract

A regeneration method of a DOC(Diesel Oxidation Catalyst) for a diesel vehicle is provided to regenerate the DOC effectively and to reduce price of the DOC by applying a simple and optimized logic and by eliminating use of an only Pt catalyst due to presence of sulfur. A regeneration method of a DOC for a diesel vehicle through a normal mode, a regeneration mode, and a heat-up mode, comprises the steps of: determining a regeneration time(S103) by monitoring a factor relating sulfur presence(S101); transferring to the regeneration mode(S105) if a transferring condition is reached by using information of surrounding conditions; estimating temperature of exhaust gas(S109) after adjusting to increase temperature at an end of DOC in the heat-up mode(S107) if a certain condition is satisfied; keeping temperature of the exhaust gas(S121) after post injection(S119) if the estimated temperature is higher than preset temperature(S111); transferring to a normal mode(S115) if low speed and low revolution is kept for a certain interval(S123); and returning to the first step(S127) after conforming termination of the regeneration mode(S125).

Description

Regeneration Logic of Diesel Vehicles {Regeneration Logic of only DOC System for disel automobile}

1 is a block diagram showing a schematic configuration of a DOC system to which the particulate filter regeneration method of a diesel vehicle according to the present invention is applied.

2 is a flow chart showing a DOC regeneration method of a diesel vehicle according to the present invention.

Explanation of symbols for the main parts of the drawings

100... Sulfur poisoning monitoring unit 200... DOC playback control

The present invention relates to the regeneration of diesel vehicles DIOC (diesel oxidation catalyst: DOC (Diesel Oxidation Catalyst), more specifically, when the diesel oxidation catalyst device (DOC) is applied to the emission post-treatment technology, the soot filter is regenerated The present invention relates to a diesel vehicle's DOC regeneration method that enables the use of Pt / Pd in DOC to improve the price competitiveness of DOC by applying simple and optimized logic.

In general, the exhaust gas refers to a gas in which a mixer combusted from an engine is released into the atmosphere through an exhaust pipe, and the exhaust gas mainly includes harmful substances such as carbon monoxide (CO), nitrogen oxides (NOx), and unburned hydrocarbons (HC). It is.

The regulation of such exhaust gas is being strengthened. Accordingly, in gasoline engines, an exhaust gas control device including an exhaust gas recirculation device, a three-way catalyst, an MPI device, and an evaporation gas control device including a canister and a purge control solenoid valve are provided. The back is applied to a vehicle.

On the other hand, although diesel engine vehicles are excellent in fuel economy and power output, unlike gasoline engines, nitrogen gas and particulate matter (PM) are relatively contained in exhaust gas. In diesel vehicles, CO and HC are emitted much less than gasoline vehicles because air is sufficiently burned in most operating conditions, but NOx and particulate matter (soot) are emitted. Nitrogen oxides (NOx) and particulate matter (PM) tend to have an inverse relationship with each other, that is, reducing nitrogen oxides increases particulate matters, and conversely, nitrogen oxides tend to increase to reduce particulate matters.

Recently, particulate matter has been identified as the main cause of air pollution, and has been found to cause great harm to humans. Accordingly, the reduction of exhaust gas of diesel vehicles is focused on the reduction of particulate matter including NOx and soot.In particular, in response to the strengthening of emission standards of diesel vehicles, particulate matter such as smoke, CO, HC, etc. A diesel soot filter (DPF) has already been put to practical use. In addition, a diesel oxidation catalyst (DOC) has been developed, and De-NOx to selectively reduce only NOx.

Catalysts and SCRs have been developed.

Diesel Particulate Filter (DPF) technology has been adopted as a method of reducing the particulate matter (PM), which has recently emerged. The diesel particulate filter is installed in an exhaust line, The diesel particulate matter is collected using a trap, and the temperature is raised above the ignition temperature of the particulate matter to burn (regenerate) the particulate matter repeatedly.

Most diesel particulate filter technology is divided into trapping technology and regeneration technology, and the system basically consists of three parts: filter, regeneration device and control device.

At this time, the temperature at which the particulate matter trapped in the diesel particulate filter is burned is 550 ~ 600 ℃ or more, but the temperature of the exhaust gas discharged due to the characteristics of the diesel engine is generally low 200 ~ 300 ℃ because the particulate matter trapped in the filter The material can not burn.

Therefore, in order to increase the temperature of the exhaust gas discharged from the diesel engine, various technologies such as post injection (post-injection), a method of raising the exhaust gas using an oxidation catalyst, and fuel additive injection are being developed.

On the other hand, there is a system that applies only a diesel oxidation catalyst device (DOC) for the regeneration method of particulate matter filter in a conventional diesel vehicle, in which the precious metal applied to the DOC due to sulfur poisoning problem is platinum (Pt) ) Only.

However, platinum, a precious metal applied to DOC, is expensive, resulting in a rise in the price of DOC, which in turn lowers the competitiveness.

Therefore, the present invention is proposed to solve the problems caused by the use of platinum in the DOC applied to the conventional diesel vehicles as described above,

It is an object of the present invention to provide efficiency in regeneration of DOC by applying simple and optimized logic for regenerating poisoned sulfur when diesel oxidation catalyst (DOC) is applied as an emission post-treatment technique. It is to provide a diesel vehicle's DIOC regeneration method that enables the use of / Pd (palladium) to improve the price competitiveness of DOC.

According to the present invention for achieving the above object "Diesel Regeneration method of diesel vehicles",

In the method of regenerating the DOC of the diesel vehicle through the normal mode, regeneration mode, heat-up mode,

a first step of determining a regeneration time of the diesel oxidation catalyst device by monitoring a factor related to sulfur poisoning;

A second step of confirming whether or not the transition to the reproduction mode is made by using the surrounding state information when the DOC is reproduced as a result of the determination, and transitioning to the reproduction mode when the transition condition to the reproduction mode is confirmed as a result;

A third step of transitioning to a heat-up mode when the predetermined condition is satisfied in the regeneration mode, adjusting the DOC trailing temperature to be increased in the heat-up mode, and estimating an exhaust temperature;

Comparing the estimated exhaust temperature with a set temperature for mode change for a predetermined time, and transitioning to the normal mode until the next operation cycle when the exhaust temperature is lower than the set temperature after a predetermined time has elapsed;

A fifth step of performing post-injection of fuel when the exhaust temperature is equal to or higher than a set temperature and maintaining the exhaust temperature at a constant temperature;

A sixth step of checking whether the low speed and the low rpm are maintained for a predetermined time while maintaining the exhaust temperature, and transitioning to the normal mode until the next operation cycle when the low speed and the low rpm are maintained for a predetermined time;

And a seventh step of checking whether the regeneration mode is terminated while the exhaust temperature is maintained, and moving to the initial state of estimating sulfur poisoning amount when the regeneration mode is terminated.

Factors related to sulfur poisoning in the first step are air amount, fuel amount, sulfur amount in fuel, sulfur amount in engine oil, and engine oil consumption.

The ambient state information of the second step is characterized in that the cooling water temperature, vehicle speed, information whether a predetermined time has elapsed after starting.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. If it is determined that the detailed description of the known function or configuration related to the present invention may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

1 is a block diagram schematically illustrating a configuration of a DOC system to which a DOC regeneration method of a diesel vehicle according to the present invention is applied.

Reference numeral 100 denotes a sulfur substance monitoring unit that detects air quantity, fuel amount, sulfur amount in fuel, sulfur amount in engine oil, engine oil consumption, air temperature and the like which are factors related to sulfur poisoning.

Reference numeral 200 determines whether the DOC is regenerated by properly calculating the value detected from the sulfur substance monitoring unit, and when the DOC is regenerated, the optimum regeneration operation is performed while effectively transitioning the normal mode, regeneration mode, and heat-up mode. A DOC regeneration control unit controlling the operation to be made.

2 is a flowchart illustrating a DOC regeneration method of a diesel vehicle according to the present invention.

As shown therein, first steps (S101 and S103) of determining a regeneration time of the diesel oxidation catalyst device (DOC) by monitoring a factor related to sulfur poisoning; A second step (S105) of determining whether or not the transition to the reproduction mode is made using the ambient state information when the DOC is reproduced as a result of the determination, and transitioning to the reproduction mode if the transition condition to the reproduction mode is confirmed as the result; A third step (S107 to S109) of transitioning to a heat-up mode if the predetermined condition is satisfied in the regeneration mode, adjusting the DOC trailing temperature to be high in the heat-up mode, and then estimating the exhaust temperature; Comparing the estimated exhaust temperature with a set temperature for mode change for a predetermined time, and if the estimated exhaust temperature is lower than the set temperature after a predetermined time elapses, a fourth step of transitioning to the normal mode until the next operation cycle (S111 to S117); A fifth step (S119, S121) of performing post-injection of fuel and maintaining the exhaust temperature at a predetermined temperature when the exhaust temperature is equal to or higher than a set temperature; A sixth step S123 of checking whether the low speed and the low rpm are maintained for a predetermined time while maintaining the exhaust temperature; ; In the state where the exhaust temperature is maintained, it is determined whether the regeneration mode is terminated, and when the regeneration mode is terminated, a seventh step (S125, S127) is performed to move to the initial state in which the sulfur poisoning amount is accumulated.

Thus, the Doxy regeneration method of the diesel vehicle according to the present invention,

First, in the normal mode as in step S101, the sulfur substance monitoring unit 100 includes factors related to sulfur poisoning (for example, air amount, air temperature, fuel amount, sulfur amount in fuel, sulfur amount in engine oil, and engine). Oil consumption, etc.) is detected and provided to the filter regeneration controller 200.

The filter regeneration control unit 200 effectively calculates various factors provided from the sulfur material monitoring unit 100 as in step S103 to determine whether to regenerate the DOC. The method of determining the regeneration time of the DOC by calculating the detection factors is a general matter of a diesel vehicle, and thus a detailed description thereof will be omitted.

If it is determined that the DOC is at the point of time of regeneration, the normal mode is shifted to the regeneration mode as in step S105, and various ambient state information (coolant temperature, vehicle speed, whether a predetermined time has elapsed after starting, etc.) is determined. If it is determined whether to perform the regeneration mode by using the () to meet a predetermined condition is changed to the heat-up mode (heat-up mode).

In the heat-up mode, adjustment is made to increase the DOC trailing temperature as in step S107, and the exhaust temperature is continuously detected and compared with the set temperature as in steps S109 and S111. Here, the set temperature is a temperature for determining whether to continue the regeneration mode or the transition to the normal mode, which is appropriately set in advance by experiment.

If the exhaust temperature is less than or equal to the set temperature, the process proceeds to step S113 to search whether a predetermined time has elapsed. If the exhaust temperature is less than or equal to the set temperature even after a predetermined time has elapsed, the process transitions to the normal mode in step S115. In the state of transition to the normal mode, as in step S117, it is checked whether the next operation cycle has been reached, and if there is no change in the operation cycle, the normal mode, which is the current mode, is maintained; otherwise, if the operation cycle is changed, it returns to the regeneration mode of step S105. Transitions are made to perform the following operations.

On the other hand, if the exhaust temperature is higher than the set temperature, go to step S119 and step S121 to perform a post injection (fuel injection) for regenerating the soot filter to maintain the exhaust temperature for a certain time from 550 ℃ to 700 ℃.

Here, as in step S123, it is checked whether the low speed and low rpm conditions are maintained for a certain time while regenerating the soot filter, and if the low speed and low rpm are maintained for a predetermined time, the normal mode is changed until the next operation cycle is changed. In contrast, when normal DOC reproduction is performed, otherwise, the flow proceeds to step S125 to confirm whether the reproduction mode is terminated.

As a result of this check, if the regeneration mode is not finished, the process moves to step S119. Otherwise, if the regeneration mode ends, the process moves to step S127 to return to the step of monitoring the sulfur poisoning amount.

As described above, the present invention can provide efficiency in regeneration of DOC by applying simple and optimized logic for regenerating DOC. Thus, Pt / Pd can be used without necessarily applying platinum to DOC due to sulfur poisoning. Do. Therefore, this advantage can lower the price of DOC, thereby improving the competitiveness.

The present invention is not limited to the above-described specific preferred embodiments, and various modifications can be made by any person having ordinary skill in the art without departing from the gist of the present invention claimed in the claims. Of course, such changes will fall within the scope of the claims.

According to the present invention described above, by applying a simple and optimized logic for regenerating the DOC there is an advantage that can be provided for efficiency in the reproduction of the DOC.

In addition, the sulfur poisoning problem, because it is possible to use Pt / Pd without having to apply only platinum to the DOC, by this advantage it is possible to lower the price of the DOC has the advantage of improving the competitiveness.

Claims (5)

In the method of regenerating the DOC of the diesel vehicle through the normal mode, regeneration mode, heat-up mode, Determining a regeneration time of the diesel oxidation catalyst device (DOC) by monitoring a factor related to sulfur poisoning; Determining whether a transition to the playback mode is made by using ambient state information when the DOC is a playback time as a result of the determination of the playback time, and transitioning to the playback mode when the transition to the playback mode is confirmed as a result; Transitioning to the heat-up mode when a certain condition is satisfied in the regeneration mode, adjusting the DOC trailing temperature to be increased in the heat-up mode, and then estimating the exhaust temperature; Performing post-injection of fuel when the estimated exhaust temperature is equal to or higher than the set temperature, and maintaining the exhaust temperature at a predetermined temperature; Checking whether the low speed and the low speed (rpm) are maintained for a certain time while maintaining the exhaust temperature, and transitioning to the normal mode until the next operation cycle when the low speed and the low speed are maintained for a predetermined time; Checking whether the regeneration mode is terminated while the exhaust temperature is maintained, and moving to the initial state of detecting sulfur poisoning amount when the regeneration mode is terminated; Doxy regeneration method of a diesel vehicle comprising a. The method of claim 1, further comprising: comparing the exhaust temperature with a set temperature for mode change for a predetermined time, and transitioning to the normal mode until the next operation cycle when the exhaust temperature is lower than the set temperature after a predetermined time has elapsed; Diocese regeneration method of the diesel vehicle further comprising a. The method of claim 1, wherein the factors related to sulfur poisoning are air content, fuel amount, sulfur content in fuel, sulfur content in engine oil, and engine oil consumption. The method of claim 1, wherein the ambient state information is cooling water temperature, vehicle speed, information on whether a predetermined time has elapsed after starting. The method of claim 1, wherein the predetermined temperature is 550 ° C ~ 700 ° C Diosi regeneration method of a diesel vehicle.

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