KR19990019805A - How to limit exhaust gas temperature - Google Patents

Abstract

According to the present invention, the exhaust gas temperature may be excessively increased due to the deviation between the engine or the environmental difference between the vehicle under test and the actual vehicle according to the conventional fuel amount and ignition timing matching method. Because of the problem of deterioration of the catalyst material, the first step of setting the initial value of fuel amount correction (INJINI) to 0 and checking whether the temperature of the exhaust gas is above the limit value, and the fuel amount correction value (INJ _i ) to increase the fuel amount INJ _w and increase the fuel amount correction value INJ _w to control the fuel amount, and if the fuel amount correction value INJ _i is equal to or greater than the fuel amount correction limit value INLIM, the third step of stopping the fuel amount correction control In addition, the temperature of the exhaust gas does not exceed the limit in case of overload, thereby preventing the thermal damage of the engine and catalyst material due to the high temperature of the exhaust gas. It relates to the exhaust gas temperature limit how you can improve the castle.

Description

How to limit exhaust gas temperature

The present invention relates to a method of limiting the temperature rise of the exhaust gas so as not to damage the engine-related components by the exhaust gas in the high load region, in particular by increasing the amount of fuel in the high load region or by advancing the ignition timing to prevent post combustion The present invention relates to a method for limiting exhaust gas temperature, which can prevent engine-related components from being damaged due to high temperature of gas or deterioration of catalyst material.

In general, the fuel amount and the ignition timing are used by matching values according to the load on the engine and the engine speed (RPM). At this time, in the high load (WOT) region or the high rotation (High RPM) region, the exhaust temperature increases considerably. That is, the temperature of the exhaust gas discharged by increasing the temperature inside the combustion chamber is also increased.

Therefore, in the vehicle test, the exhaust temperature is matched when the ignition timing and the fuel amount of the vehicle under test are matched. That is, a map for a separate WOT (high load region) having a different transition from the normal fuel amount map or the ignition timing map is added. At this time, the ignition timing and the fuel amount are matched so that the temperature of the exhaust gas in the exhaust manifold is not higher than 850 ° C.

However, in the conventional fuel amount and ignition timing matching method, the exhaust temperature may be excessively increased due to the deviation between the engine or the environmental difference between the vehicle under test and the actual vehicle, so that engine components may be damaged due to thermal damage or catalyst. There is a problem that the catalytic material of the converter deteriorates.

That is, even if the engine is manufactured through the same process, a certain deviation cannot be avoided, so the fuel amount and ignition timing matched by the vehicle under test may not be appropriate in the actual vehicle, and the vehicle under test has an ambient temperature of 20 to 30 ° C. Although the test is carried out in a maintained state, the actual vehicle may have an ambient temperature of 40 to 50 ° C. or higher. Even if the fuel amount and the ignition timing are matched so that the exhaust temperature of the vehicle under test is 850 ° C. or lower, the exhaust temperature of the vehicle is higher than that. This can be

However, when the temperature inside the combustion chamber is the same, when the fuel amount is increased or the ignition timing is advanced, the temperature of the exhaust gas is lowered. This is because the post-combustion does not proceed due to the lack of oxygen or the fuel is almost completely burned in the combustion chamber so that the post-combustion does not occur in the exhaust manifold.

The present invention has been made to solve the above-mentioned problems of the prior art, by further correcting the normal map value by using the point that the exhaust temperature is lowered when the fuel amount is increased in the high load region or the ignition timing is advanced, exhaust It is an object of the present invention to provide an exhaust gas temperature limiting method which prevents the temperature from being excessively raised to prevent thermal damage to engine components and catalyst materials.

In addition, by controlling the fuel amount and the ignition timing using a conventional map, it provides a method for limiting the exhaust gas temperature to facilitate the creation of the air volume map and the ignition timing map without requiring a separate test for adding a high load map. Its purpose is to.

1 is a flow chart illustrating a method for limiting the exhaust gas temperature according to the present invention,

2 is a flowchart illustrating another embodiment of the present invention.

* Explanation of symbols for main parts of the drawings

INJINI: Initial fuel level correction INJ _i : Fuel level correction

INJNORM: Fuel Level Map INJ _W : Corrected Fuel Level

INJLIM: Fuel level correction limit

SPKINI: Initial ignition timing correction SPK _i : Ignition timing correction

SPKNORM: Ignition timing map SPKADV: Correction timing

SPKLIM: ignition timing correction limit

The present invention provides a first step of setting the fuel amount correction initial value to 0 and checking whether the temperature of the exhaust gas is greater than or equal to the limit value, and controlling the fuel amount by calculating the corrected fuel amount while increasing the fuel quantity correction value if the temperature of the exhaust gas is greater than or equal to the limit value. And a third step of stopping the fuel amount correction control if the fuel amount correction value is equal to or higher than the fuel amount correction limit value.

In addition, the first step of setting the initial value of the ignition timing correction to 0 and confirming whether the temperature of the exhaust gas is above a certain level, and calculating the ignition timing by calculating the corrected ignition timing while increasing the ignition timing correction value when the temperature of the exhaust gas is above a certain level. And a third step of controlling the ignition timing correction value if the ignition timing correction value is equal to or greater than the ignition timing correction limit value.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

In the exhaust gas temperature limiting method of the present invention, as shown in FIG. 1, the first step of setting the fuel amount correction initial value INJINI to 0 and checking whether the temperature of the exhaust gas is above the limit value and the temperature of the exhaust gas are above the limit value If the stopping the fuel amount correction value (INJ _i) a is increased while correcting the amount of fuel (INJ _W) for operation by a second step of controlling the fuel amount, fuel amount correction value (INJ _i) the fuel quantity correction limit value (INILIM) more than the fuel amount correction control It consists of three steps.

At this time, the second step is obtained by adding the fuel amount correction value (INJ _i) a first process and a fuel amount map value (INJNORM) to set a value obtained by adding 1 to the amount of fuel corrected initial value (INJINI) a fuel correction value (INJ _i) value Comparing the second process of calculating the correction fuel amount INJ _W with the fuel level correction value INJ _i and the fuel level correction limit value INJLIM, and the fuel level correction value INJ _i is less than the fuel level correction limit value INJLIM. _i-1 ), and adds 1 to the third step of feeding back to the first step.

In the exhaust gas temperature limiting method of the present invention configured as described above, when the temperature of the exhaust gas rises above a predetermined value, the fuel injection amount is increased to lower the temperature of the exhaust gas.

When the vehicle is traveling at low speed, fuel injection is performed in accordance with the normal fuel amount map INJNORM. At this time, when the running speed increases, the engine becomes a high load (WOT) state, so that the temperature of the exhaust gas increases while the temperature of the engine increases. Therefore, the temperature of the exhaust gas is limited through the fuel injection amount correction.

First, the temperature of the exhaust gas is sensed with the fuel amount correction value INJINI set to zero. At this time, if the temperature of the exhaust gas exceeds the limit value, the amount of fuel is increased. In other words, thus by calculating each time the cycle proceeds fuel amount correction value correcting the amount of fuel (INJ _W) going to increase the (INJ _i) by one, and injects fuel according to the corrected fuel quantity (INJ _W) lowering the temperature of the exhaust gas. At this time, the correction fuel amount INJ _W is a value obtained by adding the fuel amount correction value INJ _i to the fuel amount obtained from the fuel amount map INJNORM.

Increasing the amount of fuel consumes a lot of oxygen when the combustion occurs in the engine, so that the post-combustion in the exhaust manifold does not occur when the exhaust gas is opened and discharged. Thus, the temperature of the exhaust gas is lowered.

If the fuel level correction value (INJ _i ) is less than the correction limit value (INJLIM), and the fuel level correction value (INJ _i-1 ) is added to the previous fuel level correction value (INJ _i-1 ), the fuel level correction value (INJ _i ) and the correction fuel amount (INJ _W ) are reset. Calculate and repeat the above process. If it exceeds the correction limit (INJLIM), stop the fuel level correction.

In addition, another embodiment of the present invention is the first step of setting the ignition timing correction initial value (SPKINI) to 0 as shown in FIG. than if the ignition timing correction value if the ignition timing (SPK _i) the increased while correcting the second step calculates the ignition timing (SPKADV) controlling the ignition timing, the ignition timing correction value (SPK _i) the ignition timing correction limit value (SPKLIM) above And a third step of stopping the correction control.

At this time, the second stage ignition timing correction value to the first process and the ignition timing map value (SPKNORM) to set a value obtained by adding 1 to the ignition timing correction initial value (SPLINI) by the ignition timing correction value (SPK _i) (SPK _i) a second step of calculating a sum value to a correction ignition timing (SPKADV) and, the ignition timing correction value (SPK _i) with the correction value when compared to the ignition timing correction limit value (SPKLIM) lighting (SPK _i) the ignition timing correction limit value (SPKLIM If less than), it is composed of a third process of feeding back to the first step by adding 1 to the previous ignition timing correction value SPK _i-1 .

In another embodiment of the present invention configured as described above, when the temperature of the exhaust gas rises above a predetermined value, the ignition timing is advanced to lower the temperature of the exhaust gas.

First, the temperature of the exhaust gas is sensed with the ignition timing correction value SPKINI set to zero. At this time, if the temperature of the exhaust gas exceeds the limit value, advance the ignition timing. That is, each time the cycle proceeds, the ignition timing correction value SPK _i is increased by 1 to calculate the correction ignition timing SPKADV, and the ignition timing is advanced according to the correction ignition timing SPKADV to lower the exhaust gas temperature. do. At this time, the correction ignition timing SPKADV is a value obtained by advancing the ignition timing obtained from the ignition timing map SPKNORM by the ignition timing correction value SPK _i .

When the ignition timing is advanced, combustion in the engine occurs quickly, so that combustion is almost completely performed in the engine, and after combustion is not exhausted, the exhaust manifold does not occur in the exhaust manifold. Thus, the temperature of the exhaust gas is lowered.

At this time, when the exhaust gas temperature is lowered below the limit value compared to the limit value, the above-described process is repeated. When the exhaust gas temperature is higher than the limit value, the ignition timing correction value SPK _i and the ignition timing correction limit value SPKLIM are compared.

If the ignition timing correction value SPK _i is less than the correction limit value SPKLIM, and the ignition timing correction value SPK _i-1 is added to the previous ignition timing correction value SPK _i-1 , the ignition timing correction value SPK _i and the corrected ignition timing value SPKADV ) Is calculated again, and the above process is repeated. If it exceeds the correction limit value (SPKLIM), the ignition timing correction is stopped.

Of course, the above embodiments may be simultaneously implemented. If the temperature of the exhaust gas rises above the limit, the amount of fuel is increased and the ignition timing is advanced to prevent post-combustion in the exhaust manifold, so that the engine or catalyst material may be damaged by the high temperature of the exhaust gas. Do not In this case, the reason why the correction limit value is provided at the fuel injection amount and the ignition timing is to prevent the deterioration in driving performance or knocking.

As such, the exhaust gas temperature limiting method of the present invention does not exceed the limit temperature of the exhaust gas when the overload has the advantage of improving durability by preventing thermal degradation of the engine and the catalyst material due to the high temperature of the exhaust gas.

Claims (5)

A first step of setting the initial fuel amount correction value to 0 and checking whether the temperature of the exhaust gas is above the limit value; and a second step of controlling the fuel amount by calculating the corrected fuel amount while increasing the fuel amount correction value if the temperature of the exhaust gas is above the limit value; And a third step of stopping the fuel amount correction control if the fuel amount correction value is equal to or greater than the fuel amount correction limit value. The method of claim 1, wherein the second step comprises: a first step of setting a fuel amount correction value by adding 1 to a fuel amount correction initial value; and a second step of calculating a fuel amount map value by adding a fuel amount correction value as a correction fuel amount; Comparing the ignition timing correction value and the ignition timing correction limit value, and if the ignition timing correction value is less than the ignition timing correction limit value, the exhaust gas temperature limitation, comprising a third process of feeding back to the first step by adding 1 to the immediately before ignition timing correction value. Way. The first step of setting the initial value of ignition timing correction to 0 and checking whether the exhaust gas temperature is above a certain level, and controlling the ignition timing by calculating the corrected ignition timing while increasing the ignition timing correction value when the temperature of the exhaust gas is above a certain level. And a third step of stopping the ignition timing correction control if the ignition timing correction value is equal to or greater than the ignition timing correction limit value. [4] The method of claim 3, wherein the second step comprises: a first step of setting a value obtained by adding 1 to an ignition timing correction value as an ignition timing correction value, and calculating a value obtained by adding an ignition timing correction value to an ignition timing map value as a correction ignition timing; A second process comparing the ignition timing correction value with the ignition timing correction limit value; and a third process of feeding back to the first step by adding 1 to the previous ignition timing correction value when the ignition timing correction value is less than the ignition timing correction limit value. Method for limiting the exhaust gas temperature, characterized in that consisting of. The exhaust gas temperature limiting method according to claim 1 or 3, wherein the fuel amount correction control of claim 1 and the ignition timing correction control of claim 3 are simultaneously performed.