KR20020087728A - A fuel injection compensating apparatus and method in case of fuel system error breakdown - Google Patents

Abstract

PURPOSE: A compensation is calculated appropriately when a catalyst in fuel system is deteriorated to control exhaust gas properly and reduce air pollution. CONSTITUTION: A device for compensating fuel amount comprises a first sensor(14) to detect oxygen density of exhaust gas to a catalyst. A second sensor(15) detects oxygen density of exhaust gas which passed through the catalyst. An engine control member(20) receives the detected value of the first and second sensor, and accumulates the values for a certain time according to rich/lean of the value to calculate purifying degree of the catalyst and to compensate fuel amount.

Description

A fuel injection compensating apparatus and method in case of fuel system error breakdown}

The present invention relates to a fuel amount compensation device and method thereof in deterioration of a fuel system. More specifically, in the fuel amount compensation device, an increase in exhaust gas is obtained by appropriately calculating a compensation amount due to deterioration in a fuel system deterioration. The present invention relates to a fuel amount compensation device and a method for deteriorating a fuel system in order to prevent pollution.

In general, the air-fuel ratio control using the oxygen sensor determines whether the combustion state of the engine is rich combustion or lean combustion according to the signal of the oxygen sensor that detects the oxygen concentration in the exhaust gas, and compensates the air-fuel ratio accordingly. In this way, it was proposed as a method for reducing the exhaust gas by operating in the vicinity of an appropriate theoretical air-fuel ratio (λ = 1).

That is, due to the signal voltage from the oxygen sensor output according to the oxygen concentration in the exhaust gas, the engine control unit (ECU) has a rich air-fuel ratio of the supply mixer when the electromotive force of the oxygen sensor is higher than the comparative voltage. The fuel injection amount is reduced by controlling the energization time of the fuel injector to be shortened. When the electromotive force of the oxygen sensor is lower than the comparative voltage, it is determined that the air-fuel ratio of the supply mixer is thinner than the theoretical air-fuel ratio and the solenoid valve of the fuel injector ( By controlling the energization time of the solenoid valve, the exhaust gas was reduced by increasing the fuel injection amount.

In such an air-fuel ratio control method, in order to precisely control the exhaust gas according to the normal operation of the catalyst or the efficiency of reducing the exhaust gas of the catalyst, a dual oxygen sensor air-fuel ratio control device having two oxygen sensors before and after the catalyst is used. have.

An example of such a conventional prior art is shown in FIG. 1, after a certain period of time after starting (S1), the temperature of the engine coolant exceeds 88 degrees (S2), and with an air flow sensor (AFS). In a state where the engine coolant temperature sensor and the oxygen sensor operate normally (S3), an average feedback gain is calculated (S4).

Then, the fuel correction amount is calculated using the average feedback gain calculated in the step S4 (S5), and the amount of correction fuel to be injected is calculated using the value to control the injector to inject as much as the corresponding amount (S6). ).

By doing the above, the fuel injection amount approaching the theoretical air-fuel ratio is corrected. In this conventional technique, simply applying a feedback gain synchronized with the oxygen sensor is suitable for real-time fuel amount control, Even when deterioration occurs, there is a problem in that the exhaust gas is excessively discharged because the amount of fuel is not corrected for deterioration of the catalyst.

Therefore, an object of the present invention is to solve the problems of the prior art as described above, it is possible to prevent pollution by appropriately calculating the exhaust gas control by appropriately calculating the compensation amount due to deterioration even during catalyst deterioration of the fuel system. SUMMARY OF THE INVENTION An object of the present invention is to provide a fuel amount compensating apparatus and a method thereof for deteriorating a fuel system.

1 is a flow chart of applying the fuel system fuel amount compensation method of the prior art,

2 is a block diagram to which a fuel amount compensation device is applied when a fuel system is deteriorated according to an exemplary embodiment of the present invention;

3 is a flowchart illustrating an operation of applying a fuel amount compensation method during deterioration of a fuel system according to an exemplary embodiment of the present invention.

The configuration of the present invention for achieving the above object,

A first oxygen sensor for detecting an oxygen concentration of exhaust gas flowing to the catalyst;

A second oxygen sensor for detecting the oxygen concentration of the exhaust gas passing through the catalyst;

And an engine control means for receiving the values detected by the first oxygen sensor and the second oxygen sensor, calculating the catalyst purity by accumulating the value for a predetermined time according to the rich / lean, and correcting the fuel amount.

Another configuration of the present invention for achieving the above object,

Summing respective rich / lean times by reading signals from a first oxygen sensor for detecting the oxygen concentration of the exhaust gas flowing into the catalyst and a second oxygen sensor for detecting the oxygen concentration of the exhaust gas passing through the catalyst;

Calculating the rich and lean ratio of the first oxygen sensor and the second oxygen sensor according to the calculated value;

Calculating a catalyst purification degree for a predetermined time according to the ratio calculated above;

Calculating a fuel correction ratio according to the catalyst purification degree calculated above;

And injection control of the fuel amount corrected according to the fuel correction ratio calculated above.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the present invention.

As shown in FIG. 1, the configuration of a fuel amount compensating device at the time of deterioration of a fuel system according to an exemplary embodiment of the present invention is performed as follows.

Ignition switch (11) for detecting the starting state of the vehicle engine,

Coolant temperature sensor 12 for sensing the temperature of the engine coolant,

An air mass sensor 13 for sensing the amount of air sucked into the engine;

A first oxygen sensor 14 for detecting the oxygen concentration of the exhaust gas flowing through the catalyst,

A second oxygen sensor 15 for detecting the oxygen concentration of the exhaust gas passing through the catalyst,

The first oxygen sensor 14 and the second oxygen sensor 15 in consideration of the engine warm-up state according to the signal output from the ignition switch 11, the cooling water temperature sensor 12, and the air volume sensor 13. An engine control unit 20 which receives the detected value and advances the value for a predetermined time according to the richness / leanness to calculate the catalytic purity and correct the fuel amount;

It comprises an injector 30 for injecting the fuel amount corresponding to the value controlled by the engine control unit 20 to the engine.

Operation of the embodiment of the present invention made as described above is as follows.

The ignition switch 11 outputs a signal according to the starting state of the vehicle engine, and the coolant temperature sensor 12 detects the temperature of the vehicle engine coolant and outputs a signal accordingly.

The air amount sensor 13 detects and outputs the amount of air sucked into the engine, and the first oxygen sensor 14 mounted at the front end of the catalyst of the exhaust gas pipe detects and outputs the oxygen concentration of the exhaust gas flowing through the catalyst. The second oxygen sensor 15 mounted at the rear end of the catalyst detects and outputs an oxygen concentration of the exhaust gas passing through the catalyst.

The engine control unit 20 receives a signal output from the ignition switch 11, the coolant temperature sensor 12, and the air mass sensor 13 to determine whether the state of the engine is warmed up. The value detected by the first oxygen sensor 14 and the second oxygen sensor 15 is input, and the value is accumulated for a predetermined time according to the richness / leanness to calculate the catalyst purity and to correct the fuel injection amount supplied to the engine. do.

The injector 30 injects the fuel amount corresponding to the value controlled by the engine control unit 20 to the engine.

Hereinafter, the operation of the engine control unit 20 will be described in detail with reference to FIGS. 3A and 3B.

The engine control unit 20 determines whether or not the vehicle engine is warmed up after a predetermined time has elapsed according to the state of the ignition switch 11 (S10).

When warming up, the engine control unit 20 reads a signal from the coolant temperature sensor 12 and determines whether or not the coolant temperature reaches a preset reference temperature of 88 ° C. (S20).

When the coolant temperature is greater than or equal to the reference temperature in the step (S20), the engine control unit 20 is the air amount sensor 13, the coolant temperature sensor 12, the first oxygen sensor 14 and the second oxygen sensor 15 By judging whether it operates normally, it is determined whether it is ready to start fuel quantity correction control (S30).

When all the sensors operate normally in step S30, the engine control unit 20 receives signals output from the first oxygen sensor 14 and the second oxygen sensor 15 at step S40. By summing the time according to the rich / lean burn for each oxygen sensor to the existing time (S50).

In FIG. 4, the signals output from the first oxygen sensor 14 and the second oxygen sensor 15 become as a) and b), respectively, and one cycle of the first oxygen sensor 14 corresponds to lean combustion. It consists of the sum of the corresponding time (T_UP_Lean) and the time corresponding to the rich combustion (T_UP_Rich), and one cycle of the second oxygen sensor 15 corresponds to the lean burn time (T_DN_Lean) and the time corresponding to the rich combustion. It consists of the sum of (T_DN_Rich).

The engine control unit 20 calculates the rich ratio and the lean ratio after taking the time corresponding to each combustion for each sensor, and takes the average value.

That is, the rich ratio Rich_Ratio is calculated as in Equation 1 below, and the lean ratio Lean_Ratio is calculated as in Equation 2 below.

Rich ratio (Rich_Ratio) = average value {second oxygen sensor rich time (T_DN_Rich) / first oxygen sensor rich time (T_UP_Rich)}

Lean ratio (Lean_Ratio) = average value {second oxygen sensor lean time (T_DN_Lean) / first oxygen sensor lean time (T_UP_Lean)}

After calculating the rich ratio and the lean ratio as an average value as described above, the engine control unit 20 calculates a new average purification amount by adding the lean ratio and the rich ratio calculated above to the existing average purification amount. Equation 3 is as follows.

Average Purification Amount (Min_Cat) = Conventional Average Purification Amount (Min_Cat_b) + Average Value {Lean_Ratio, Rich_Ratio}

Then, by calculating the average correction amount calculated above to the existing catalyst purification degree, a new catalyst purification degree is calculated, as shown in Equation 4 below (S70).

Catalyst Purification Degree (CAT_M) = Conventional Catalyst Purification Degree (CAT_M_b) + Average Purification Amount (Min_Cat)

By calculating the degree of catalyst purification as described above, check whether the period has passed by a predetermined number (S80), if not yet the number set, return to step (S20) to check again whether the cooling water temperature is above the reference temperature, The operation of the above steps (S40 to S70) is repeated until the number is accumulated and accumulated.

However, when the calculation period passes by the number set in the step S80, the fuel correction ratio is calculated using the values calculated above, and is equal to the following Equation 5 (S90).

Fuel correction ratio (T_DN_R) = sum of the second oxygen sensor rich time (Sum_T_DN_Rich) + sum of the second oxygen sensor lean time (Sum_T_DN_Lean)

Then, the engine control unit 20 calculates the air intake time using the catalyst purification degree calculated above, calculates the fuel injection time using the fuel correction ratio calculated above, and follows the preset function.

In addition, the engine control unit 20 calculates the amount of corrected fuel using the fuel correction ratio calculated above, as shown in Equation 6 below (S100).

Corrected fuel amount = fuel injection time * fuel correction ratio (T_DN_R)

Then, the engine control unit 20 outputs a fuel injection control signal according to the air intake time and the corrected fuel amount calculated above (S110), and the injector 30 injects fuel to the engine according to the signal.

As described above, the operation is continuously performed until the engine is turned off (S120). As shown in FIG. 4C, when the purification efficiency of the catalyst is high, the signal of the second oxygen sensor is determined by the rich combustion time. The ratio is high.

By operating as described above, when the catalyst for purifying exhaust gas deteriorates and the performance is deteriorated, by adjusting the fuel correction ratio according to the symptom, it is possible to prevent unnecessary increase in exhaust gas compared with the prior art, and the reference number is And the air intake time calculation function and the fuel injection time calculation function can be set differently according to the type and condition of the engine.

Therefore, the present invention operating as described above has an effect of preventing pollution by appropriately calculating the amount of compensation according to the deterioration even when the catalyst deterioration of the fuel system is properly controlled.

Claims (2)

A first oxygen sensor for detecting an oxygen concentration of exhaust gas flowing to the catalyst; A second oxygen sensor for detecting the oxygen concentration of the exhaust gas passing through the catalyst; And an engine control means which receives the values detected by the first oxygen sensor and the second oxygen sensor, calculates the catalyst purity by accumulating the value for a predetermined time according to the rich / lean, and corrects the fuel amount. A fuel amount compensation device at the time of deterioration of the fuel system. Summing respective rich / lean times by reading signals from a first oxygen sensor for detecting the oxygen concentration of the exhaust gas flowing into the catalyst and a second oxygen sensor for detecting the oxygen concentration of the exhaust gas passing through the catalyst; Calculating the rich and lean ratio of the first oxygen sensor and the second oxygen sensor according to the calculated value; Calculating a catalyst purification degree for a predetermined time according to the ratio calculated above; Calculating a fuel correction ratio according to the catalyst purification degree calculated above; And controlling fuel injection to the fuel amount corrected according to the fuel correction ratio calculated as described above.