Internal combustion engine aftertreatment thermal management system

Abstract

The invention discloses an internal combustion engine after-treatment heat management system, relates to the field of internal combustion engine control, and solves the technical problem that the mode of adding fuel injection at the front end of an existing DOC easily causes spontaneous combustion of a vehicle. The system comprises a cooling liquid circulation pipeline, an electromagnetic valve and a variable-frequency cooling water pump, the electromagnetic valve and the variable-frequency cooling water pump are installed on the cooling liquid circulation pipeline, the cooling liquid circulation pipeline is installed on a DPF, when the DPF enters the temperature rising stage of active regeneration, whether the DPF has the over-temperature risk or not is evaluated by predicting the temperature of the DPF, if yes, the electromagnetic valve is controlled to be opened, and if not, the variable-frequency cooling water pump is controlled to be closed. And cooling liquid is fed into the cooling liquid circulating pipeline, so that the DPF is cooled to a preset target temperature. The working conditions of the internal combustion engine and the whole vehicle are effectively monitored, post-processing and active control over the temperature of surrounding combustible materials are achieved, and therefore invalid energy loss is reduced, oil consumption and hardware loss are reduced, and reliability and durability are improved.

Description

Technical Field

[0001] The present invention relates to the field of internal combustion engine control, and more particularly, to an internal combustion engine aftertreatment thermal management system. Background Art

[0002] The diesel engine's after-treatment particulate filter (DPF) has an internal unit structure (usually made of ceramic or metal materials with a microporous structure) that captures these particulates. The carbon particles will accumulate and increase in the collector. When the carbon particles are collected to a certain stage and the engine exhaust back pressure exceeds the limit or the regeneration mileage exceeds the limit, the engine's power and economy decrease, and regeneration is required. By controlling the intake and fuel injection in the internal combustion engine cylinder, the DOC is used to assist in raising the temperature in the particulate filter, allowing the carbon particles to react with oxygen for combustion.

[0003] Active regeneration of DPF is mainly achieved by increasing fuel injection at the front end of DOC, raising the DPF inlet temperature to above 580°C through DOC oxidation and heating, thereby igniting the soot particles inside the DPF and achieving soot regeneration. However, when the DOC or the fuel injection system at the front end of the DOC fails, the temperature inside the DPF may become uncontrolled, which may cause the outside of the DPF to overheat and ignite surrounding combustibles, ultimately causing the vehicle to spontaneously combust. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide an internal combustion engine after-treatment thermal management system in view of the deficiencies in the prior art, and to solve the technical problem that the existing method of adding fuel injection at the front end of the DOC easily causes vehicle spontaneous combustion.

[0005] The internal combustion engine aftertreatment thermal management system described in the present invention includes a coolant circulation pipeline and a solenoid valve and a variable frequency cooling water pump installed on the coolant circulation pipeline. The coolant circulation pipeline is installed on the DPF. When the DPF enters the temperature rise stage of active regeneration, the temperature of the DPF is predicted and evaluated to determine whether the DPF has an over-temperature risk. If so, the solenoid valve is controlled to open so that coolant can enter the coolant circulation pipeline to cool the DPF to a preset target temperature.

[0006] As a further improvement, the temperature prediction is specifically as follows:

[0007] Obtaining the real-time temperature value and temperature change rate at the DPF inlet;

[0008] When the temperature change rate is greater than the preset predicted change rate, the opening of the solenoid valve is opened to a preset first opening so that the temperature change rate is equal to or less than the predicted change rate;

[0009] When the real-time temperature value at the DPF inlet is greater than or equal to a preset first temperature value, the solenoid valve is fully opened;

[0010] When the real-time temperature value at the DPF inlet is greater than or equal to a preset second temperature value, and the temperature change rate is greater than or equal to a preset first change rate, the solenoid valve is fully opened.

[0011] Furthermore, when the opening of the solenoid valve is opened to a preset first opening, the rotation speed of the cooling fan is increased to a preset first rotation speed, and the power of the variable frequency cooling water pump is increased to a first power.

[0012] Furthermore, when the solenoid valve is fully opened, the rotation speed of the cooling fan is increased to a maximum rotation speed, and the power of the variable frequency cooling water pump is increased to a rated power.

[0013] Furthermore, when the real-time temperature of the DPF is greater than a set high temperature threshold and less than a second temperature value, if the vehicle's operating state is an emergency stop, the solenoid valve is controlled to be fully opened, and the speed of the cooling fan is controlled to increase to the maximum speed, and the power of the variable frequency cooling water pump is increased to the rated power.

[0014] Furthermore, the high temperature threshold is 530°C-570°C.

[0015] Furthermore, when the real-time temperature of the DPF is greater than a set high temperature threshold and less than a second temperature value, if the vehicle is in an accelerated driving state, the speed of the cooling fan is controlled to be reduced to a first speed, and the power of the variable frequency cooling water pump is reduced to a first power, so as to achieve active insulation of the DPF.

[0016] Furthermore, a delay time is set, and when the internal combustion engine is turned off, the delay time starts to count and the cooling fan is turned on; when the delay time ends, the cooling fan is turned off.

[0017] Beneficial Effects

[0018] The advantages of the present invention are:

[0019] The present invention evaluates the over-temperature risk of the DPF by predicting the temperature of the DPF, and controls the solenoid valve, cooling fan and variable frequency cooling water pump to cool the DPF to a preset target temperature according to whether the over-temperature risk of the DPF exists, thereby effectively and reasonably utilizing energy, reducing heat loss in the heating condition of the post-processing of the internal combustion engine, and reducing fuel consumption; avoiding the spontaneous combustion of the vehicle; effectively monitoring the working conditions of the internal combustion engine and the whole vehicle, and realizing active control of the temperature of the post-processing and surrounding combustibles, thereby reducing ineffective energy loss, reducing fuel consumption and hardware loss, and improving its reliability and durability. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is the overall structural diagram of the internal combustion engine aftertreatment thermal management system of the present invention.

[0021] Among them, 1-ECU, 2-coolant circulation pipeline, 3-variable frequency cooling water pump, 4-intercooler, 5-solenoid valve, 6-cooling fan, 7-DOC, 8-DPF. DETAILED DESCRIPTION

[0022] The present invention will be further described below in conjunction with the embodiments, but it does not constitute any limitation to the present invention. Any limited number of modifications made by anyone within the scope of the claims of the present invention are still within the scope of the claims of the present invention.

[0023] See also Figure 1 The internal combustion engine aftertreatment thermal management system of the present invention includes a coolant circulation pipeline 2 and a solenoid valve 5 and a variable frequency cooling water pump 3 installed on the coolant circulation pipeline 2.

[0024] The coolant circulation pipeline 2 is installed around the combustible material of the DPF8 of the internal combustion engine chassis to cool the DPF8 of the internal combustion engine.

[0025] The solenoid valve 5 is installed at the connection between the coolant circulation pipeline 2 and the main cooling pipeline, and is used to control the on-off of the coolant in the coolant circulation pipeline 2.

[0026] The variable frequency cooling water pump 3 is installed in the pipeline of the coolant circulation pipeline 2 and is used to control the flow rate of the coolant in the coolant circulation pipeline 2.

[0027] The cooling fan 6 is installed on the side of the internal combustion engine where the heat is higher when the internal combustion engine is working, and is used to cool the internal combustion engine.

[0028] The DPF pre-temperature sensor is installed at the inlet of the DPF8 of the internal combustion engine and is used to obtain the temperature value and temperature change rate at the inlet of the DPF8 of the internal combustion engine.

[0029] When DPF8 enters the temperature rising stage of active regeneration, whether DPF8 has an over-temperature risk is evaluated by predicting the temperature of DPF8. If so, the solenoid valve 5 is controlled to open to allow the coolant to enter the coolant circulation pipeline to cool DPF8 to a preset target temperature.

[0030] The temperature forecast is as follows:

[0031] When it is detected that the internal combustion engine needs to be regenerated and heated, the speed of the cooling fan 6 is controlled to be reduced to the minimum speed that meets the thermal management of the entire vehicle. The minimum speed is calibrated according to the vehicle speed and the water temperature of the internal combustion engine, and the variable frequency cooling water pump 3 is operated in the lowest energy consumption mode.

[0032] The real-time temperature value and temperature change rate at the inlet of DPF 8 are obtained. When the temperature change rate is greater than the preset predicted change rate, the opening of the solenoid valve 5 is opened to the preset first opening so that the temperature change rate is equal to or less than the predicted change rate. When the solenoid valve 5 is fully opened, the speed of the cooling fan 6 is increased to the preset first speed, and the power of the variable frequency cooling water pump 3 is increased to the first power.

[0033] When it is detected that DPF8 enters the soot combustion regeneration stage of active regeneration and the real-time temperature value at the inlet of DPF8 is greater than or equal to the preset first temperature value, the solenoid valve 5 is fully opened. When the solenoid valve 5 is fully opened, the speed of the cooling fan 6 is increased to the maximum speed, and the power of the variable frequency cooling water pump 3 is increased to the rated power. In this way, the fuel injection system is coordinated to quickly reduce the overheated DPF8, thereby achieving the maximum efficiency of physical cooling of the post-processing and surrounding combustibles to avoid vehicle spontaneous combustion. The first temperature value in this embodiment is 790°C.

[0034] When the real-time temperature value at the inlet of DPF8 is greater than or equal to the preset second temperature value, and the temperature change rate is greater than or equal to the preset first change rate, the solenoid valve 5 is fully opened. When the solenoid valve 5 is fully opened, the speed of the cooling fan 6 is increased to the maximum speed, and the power of the variable frequency cooling water pump 3 is increased to the rated power. In this way, the fuel injection system is used to quickly reduce the overheated DPF8, thereby achieving the maximum efficiency of physical cooling of the post-processing and surrounding combustibles to avoid vehicle spontaneous combustion. The second temperature value in this embodiment is 690°C, and the first change rate is 2°C / s.

[0035] When the real-time temperature of DPF8 is greater than a set high temperature threshold and less than a second temperature value, if the vehicle's operating state is rapid parking, the solenoid valve 5 is controlled to be fully opened, and the speed of the cooling fan 6 is controlled to increase to the maximum speed, and the power of the variable frequency cooling water pump 3 is increased to rated power.

[0036] When the real-time temperature of DPF8 is greater than a set high temperature threshold and less than the second temperature value, if the vehicle is in an accelerated driving state, the speed of the cooling fan 6 is controlled to be reduced to the first speed, and the power of the variable frequency cooling water pump 3 is reduced to the first power, so as to realize active heat preservation of DPF8. Thus, the heat loss of post-processing and surrounding combustibles is actively reduced, fuel consumption is reduced, fuel consumption and hardware loss are reduced, and its reliability and durability are improved. The high temperature threshold in this embodiment is 550°C.

[0037] The relationship between the first speed and the maximum speed is: first speed < maximum speed; the relationship between the first power and the rated power is: first power < rated power; the relationship between the first temperature value, the second temperature value and the high temperature threshold is: high temperature threshold < second temperature value < first temperature value.

[0038] The delay time is set, and when the internal combustion engine is turned off, the delay time starts to count, and the cooling fan 6 is turned on to run; when the delay time ends, the cooling fan 6 is turned off to achieve cooling of the internal combustion engine after it is turned off.

[0039] The above is only a preferred embodiment of the present invention. It should be pointed out that for those skilled in the art, several modifications and improvements can be made without departing from the structure of the present invention, which will not affect the effect of the implementation of the present invention and the practicality of the patent.

Claims

1. An internal combustion engine aftertreatment thermal management system, characterized in that: The system includes a coolant circulation pipeline and a solenoid valve and a variable frequency cooling water pump installed on the coolant circulation pipeline. The coolant circulation pipeline is installed on the DPF. When the DPF enters the temperature rise stage of active regeneration, the temperature of the DPF is predicted and evaluated to determine whether the DPF has an over-temperature risk. If so, the solenoid valve is controlled to open so that coolant can enter the coolant circulation pipeline to cool the DPF to a preset target temperature.

2. The internal combustion engine aftertreatment thermal management system according to claim 1, characterized in that: The temperature prediction is specifically as follows: Obtaining the real-time temperature value and temperature change rate at the DPF inlet; When the temperature change rate is greater than the preset predicted change rate, the opening of the solenoid valve is opened to a preset first opening so that the temperature change rate is equal to or less than the predicted change rate; When the real-time temperature value at the DPF inlet is greater than or equal to a preset first temperature value, the solenoid valve is fully opened; When the real-time temperature value at the DPF inlet is greater than or equal to a preset second temperature value, and the temperature change rate is greater than or equal to a preset first change rate, the solenoid valve is fully opened.

3. The internal combustion engine aftertreatment thermal management system according to claim 2, characterized in that: When the opening of the solenoid valve is opened to a preset first opening, the rotation speed of the cooling fan is increased to a preset first rotation speed, and the power of the variable frequency cooling water pump is increased to a first power.

4. The internal combustion engine aftertreatment thermal management system according to claim 3, characterized in that: When the solenoid valve is fully opened, the rotation speed of the cooling fan is increased to the maximum rotation speed, and the power of the variable frequency cooling water pump is increased to the rated power.

5. The internal combustion engine aftertreatment thermal management system according to claim 4, characterized in that: When the real-time temperature of the DPF is greater than a set high temperature threshold and less than a second temperature value, if the vehicle is in an emergency stop state, the solenoid valve is controlled to be fully opened, the speed of the cooling fan is controlled to be increased to the maximum speed, and the power of the variable frequency cooling water pump is increased to the rated power.

6. The internal combustion engine aftertreatment thermal management system according to claim 5, characterized in that: The high temperature threshold is 530°C-570°C.

7. The internal combustion engine aftertreatment thermal management system according to claim 6, characterized in that: When the real-time temperature of the DPF is greater than a set high temperature threshold and less than a second temperature value, if the vehicle is in an accelerated driving state, the speed of the cooling fan is controlled to be reduced to a first speed, and the power of the variable frequency cooling water pump is reduced to a first power, so as to achieve active insulation of the DPF.

8. The internal combustion engine aftertreatment thermal management system according to claim 1, characterized in that: A delay time is set. When the internal combustion engine is turned off, the delay time starts and the cooling fan is turned on; when the delay time ends, the cooling fan is turned off.

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