KR19980013972A - Method and apparatus for torque shock control during air-fuel ratio transition of lean-burn engine - Google Patents

Abstract

The present invention relates to an apparatus and method for controlling a torque shock generated when an air-fuel ratio of a lean-burn engine changes, and more particularly, to an apparatus and method for controlling a torque shock caused by a sudden increase in fuel amount that occurs when a lean air / fuel ratio shifts to a stoichiometric air- The present invention provides an apparatus and method for controlling torque shock during engine air-fuel ratio transition for improving the operability of a lean-burn engine and improving fuel economy and preventing air pollution by preventing engine shock and harmful exhaust gas emission caused by the engine, And a control unit for controlling the recovery rate of the ignition timing after reading the air-fuel ratio according to the engine load, thereby detecting abnormal combustion with a sudden increase in the fuel amount at the transition from the lean air-fuel ratio to the stoichiometric air- To control the generation of torque shocks and the emission of harmful exhaust gases. An ignition device for performing ignition timing recovery stepwise in the transition step, an injector for adjusting the fuel injection amount by the opening time, an air addition valve driven for improving the combustion performance of the mixed fuel, The present invention relates to an apparatus and method for controlling a torque shock at the time of an air-fuel ratio change of a lean-burn engine equipped with a vortex flow control valve as a driving portion.

Description

Method and apparatus for torque shock control during air-fuel ratio transition of lean-burn engine

FIG. 1 is a block diagram of a control apparatus according to an embodiment of the present invention.

FIG. 2 is a graph showing an air-fuel ratio of a lean-burn engine equipped vehicle according to an embodiment of the present invention.

And control of the torque shock at the time of transition is executed.

FIG. 3 is an illustration of an ignition timing transition according to an embodiment of the present invention.

[Industrial Applications]

The present invention relates to a method and apparatus for controlling a torque shock generated in an air-fuel ratio transition process due to a load variation of an internal combustion engine, and more particularly, to a method and apparatus for controlling a torque shock in a lean- The present invention relates to a method and an apparatus for controlling torque shocks in the air-fuel ratio transition of a vehicle equipped with a lean-burn engine, which is provided for eliminating torque shocks generated when the engine is lean and preventing the emission of harmful gases causing air pollution.

BACKGROUND ART [0002]

Generally, lean burning vehicles for exhaust gas purification and achieving a low fuel consumption tend to cause deterioration of ignition property, and combustion speed is delayed, so combustion gas becomes unstable and output becomes low due to misfire.

Also, when the lean air-fuel ratio, which is executed only at medium speed and heavy load, shifts to the stoichiometric air-fuel ratio due to the increase in speed and the load, shock occurs due to engine output change due to the increase of fuel.

However, in this case, the air-fuel ratio, which can not be purified by the catalyst, can be reduced to 15 ~ A slight lean air-fuel ratio section of 18: 1 appeared, and there was a serious difficulty that nitrogen oxides were released in large quantities.

As countermeasures against this problem, measures have been taken to reduce the engine compression ratio or reduce the combustion temperature through exhaust gas recirculation, but nitrogen oxides and the like have not been effectively suppressed.

In the prior art, a bypass valve is used at the inlet of the throttle valve passage to close the valve at the time of transition from the lean air-fuel ratio to the stoichiometric air-fuel ratio, thereby reducing the engine intake air amount.

However, with this method, it is difficult to completely eliminate the torque shock due to the inflow of a large amount of fuel instantaneously.

[Object of the Invention]

In the case of a vehicle equipped with a lean-burn engine, it is possible to prevent a torque shock due to a change in the engine output necessarily caused by an instantaneous increase in the fuel amount when the lean air-fuel ratio is changed from the lean air-fuel ratio to the stoichiometric air- The engine speed is adjusted so as to shift from the stoichiometric air-fuel ratio to the predetermined ignition timing after the ignition timing is delayed and the torque shock due to the rapid increase of the fuel amount and the emission of nitrogen oxides can be reduced A torque shock control method and apparatus for an air-fuel ratio transition are provided.

[MEANS AND METHODS FOR SOLVING PROBLEMS]

In order to solve the above-described problems of the prior art and to achieve the object, the present invention provides a fuel injection control system for an internal combustion engine, comprising: a sensor for sensing a change in an opening degree of a throttle valve according to an engine load variation and a vehicle speed, An engine speed sensor for detecting the rotational speed of the engine, an air flow meter for detecting the amount of intake air sucked into the combustion chamber of the engine after being filtered by the air filter, and an engine speed sensor Fuel ratio sensor for accurately determining the air-fuel ratio of the exhaust gas by detecting the oxygen concentration, and a sensing unit for providing the total information of the sensing of the engine load and the correction of the ignition timing recovery speed, And proceeds with the transition to the theoretical performance ratio. And electronic ignition control unit to switch to the ignition delay time and the ignition timing of ignition stable stoichiometric air-fuel ratio by adjusting the timing for regeneration of,

A power transistor serving as a switch for inducing a high voltage by an output signal of the electronic ignition control unit; an ignition coil serving as a transformer for boosting the induced high voltage; a distributor for distributing high- An air add valve for adjusting an ignition timing while supplying a high-pressure current in the order of ignition plugs causing combustion through discharging, correcting the torque of the engine by an amount of intake air while being opened or closed in accordance with a control signal of the electronic ignition control unit, And a valve driving unit configured to generate a vortex in the room and driven to improve the ignition performance and the combustion state and determine the injection time of the fuel according to the output signal of the electronic ignition control unit that reads the engine mode information of the sensing unit, Of the injector A torque shock control apparatus for an air-fuel ratio transition of a combustion engine is provided.

Next, based on the information provided by the sensing unit, if the fuel injection time of the injector is set according to the air-fuel ratio transition, the injector driving time is determined so as to start the ignition timing recovery and the fuel is injected. In order to improve the performance, an air addition valve and a valve drive step for driving the eddy current control valve are performed.

The control unit proceeds to a timing determination step of determining whether the transition is completed at the stoichiometric air-fuel ratio ignition timing by re-driving the ignition device to combust the blended fuel mixed in the injector and the valve driving step. There is provided a torque shock control method for an air-fuel ratio transition of a lean-burn engine in which the above-described process is re-executed while the ignition timing is raised by one step after the ignition timing is maintained by looping in the stop phase.

[Example]

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

Referring to FIG. 1, a block diagram of the present invention will be described.

The engine load sensing unit 10 configured to sense the engine load variation determining the air-fuel ratio and the transition state of the ignition timing is provided with a sensor 11 for detecting the load at the position of the opening degree of the throttle valve according to the engine load variation, A sensor 12 for measuring the change in the voltage at the time of rotation of the shaft in time to sense the engine rotation speed, an air flow meter 13 for sensing the state variation of the engine with the intake air amount, a crankshaft rotation A crank angle sensor 14 for checking the angle and an air-fuel ratio sensor 15 for detecting the amount of oxygen in the exhaust gas and sensing the air-fuel ratio of the air-fuel mixture, and is connected to the electronic ignition control unit 20 to output a predetermined electric signal.

The electronic ignition control unit 20 reads the transition to the theoretical air / fuel ratio from the lean burn air / fuel ratio according to the engine load of the driven vehicle and the vehicle speed through the input electrical signal of the sensing part 10, And outputs an electric signal to the igniter 30, the valve driver 40, and the injector 50. The igniter 30, the valve driver 40,

In the ignition device 30, the ignition timing is temporarily delayed from the lean air-fuel ratio to the theoretical air-fuel ratio at the time of transition to the theoretical air-fuel ratio, The valve driving unit 40 changes the mixing ratio stepwise for combustion at the stoichiometric air-fuel ratio and increases the combustion performance, thereby preventing incomplete abnormal combustion. The injector 50 that operates to adjust the opening timing of the electronic ignition control unit 20 and injects the appropriate amount of fuel is operated based on the information of the sensing portion 10 which is changed in the course of the ignition timing recovery step .

The operation of the torque shock control according to the present invention operated through the above-mentioned device means will be described in detail in the second and third figures.

First, in the electronic ignition control unit 20 of the lean burning engine recommendation vehicle which operates at the lean burning air-fuel ratio at the same ignition timing as the state A in FIG. 3, the detection signal The engine load is detected based on the engine load (S1).

If the engine load continuously increases in step S1, the air-fuel ratio transition for combustion of the stoichiometric air-fuel ratio is determined and the process proceeds to step S4. This process involves a change in ignition timing as in the case of FIG. 3, The routine proceeds to the lean burn routine in step S3 (S2).

The ignition device is temporarily delayed by a preset value to the ECU as in the case of FIG. 3 in order to prevent the torque fluctuation due to the air-fuel ratio transition and to set the combustion condition at the stoichiometric air-fuel ratio.

The electronic ignition control unit 20 delaying the ignition device sets the fuel injection opening time of the injector 50 with the read information of the sensing portion 10 and delays the ignition timing as in the ' (S5).

In step S6, the ignition timing is maintained constant during the delay time set in step S4, and the preparation time for performing the first step of the transition process is maintained.

At the same time, the operation for closing the air addition valve 41 and opening the vortex control valve 42 is advanced (S7) so that the combustion performance can be improved by controlling the mixing ratio of the fuel and improving the ignition performance.

The progress of the above steps S6 and S7 is indicated by 'C' in FIG.

The first restart of the retarded ignition timing is now started (S8).

The initial transition process at the stoichiometric air-fuel ratio ignition timing progresses as in the first rising step of the 'R' process of FIG. 3.

If it is determined that the ignition timing of the stoichiometric air-fuel ratio has progressed as a result of the progress of the initial transition process, if the ignition timing recovery should continue, the ignition timing is corrected by looping to step S8 (S9).

The process of step S9 is illustrated by the symbol 'R' in FIG. 3, which is a step of recovering the ignition timing to prevent abnormal combustion which causes an engine shock, thereby attenuating the torque shock at the transition to the stoichiometric ratio The ignition timing recovery speed at this time is indicated by the ignition timing per ignition frequency.

For example, when the transition period of the air-fuel ratio is large due to a sudden change in the load (the "period" in FIG. 3), the ignition timing recovery speed is gradually adjusted so that the stoichiometric transition is made at the stoichiometric combustion ignition ignition timing. It will be possible to reduce the torque fluctuation.

After the transition to the theoretical air-fuel ratio ignition timing is completed as a result of step S9, it is shown that stable entry into the ignition timing step for combustion of the theoretical air-fuel ratio at the lean burning air-fuel ratio as in state B of FIG.

[Effects of the Invention]

The apparatus and method for torque shock control that occur when the air-fuel ratio of the vehicle equipped with the lean-burn engine according to the present invention is changed can achieve fuel saving and fuel economy improvement, and resource saving and environmental protection can be solved by purifying the exhaust gas.

Specifically, it is intended to improve the disadvantage of inducing a torque shock due to an abrupt increase in the amount of injected fuel due to the air-fuel ratio transition of the lean-burn engine, to prevent engine shock by delaying the ignition when shifting from the lean air-fuel ratio to the stoichiometric air-fuel ratio, And a control device and method provided for shifting to the stoichiometric air-fuel ratio ignition timing while gradually controlling the recovery speed.

According to the above-described invention, the ignition delay according to the reading is performed on the engine load, so that the drivability of the lean-burn-equipped vehicle can be improved without suffering a sharp torque shock.

In addition, it is possible to reduce the emission of nitrogen oxide, which is inevitably generated in the transient process at the time of the air-fuel ratio transition, and it is possible to alleviate the problems such as the preservation of the atmospheric environment and sintering of the engine engine.

Claims (3)

A vehicle equipped with a lean-burn engine, comprising: a sensing unit for sensing changes in engine load and ignition timing, An electronic ignition control unit for determining the air-fuel ratio and outputting a drive signal while controlling the entire cycle for recovery of the ignition timing upon transition of the air- An ignition device for gradually shifting the ignition timing by an electronic ignition control signal according to an air-fuel ratio transition, a valve driving section driven to improve the mixing ratio and the combustion performance, A torque shock control apparatus for an air-fuel ratio transition of a lean-burn engine including an injector operated in alignment. A method for controlling ignition of a vehicle equipped with a lean-burn engine, comprising the steps of: determining whether a load variation of an engine applied from each of the detection means requires a transition from a lean combustion air-fuel ratio to a stoichiometric ratio; Outputting an ignition timing delay signal to the ignition device upon determination of a combustion request of an early air-fuel ratio in the step, to initiate transition of ignition timing; A drive time setting step of correcting an opening time of the injector to adjust an ignition timing recovery speed after a constant ignition delay time, Driving the ignition device to drive the opening of the injector during the set driving time, driving the valve for adjusting the mixing ratio and improving the combustion performance, and then driving the ignition device to combust the mixed fuel, Fuel ratio is changed to a stoichiometric air-fuel ratio ignition timing to perform a recovery speed correction of the ignition timing. 3. The method of claim 2, And the ignition timing recovery speed adjusting method at the time of the air-fuel ratio transition is displayed at the ignition timing per ignition frequency.