JP3596075B2 - Fuel supply control device for internal combustion engine for vehicle - Google Patents

Description

[0001]
[Industrial applications]
The present invention relates to a fuel supply control device for an internal combustion engine having a driving force (traction) control system, and more particularly to an air-fuel ratio control technique.
[0002]
[Prior art]
2. Description of the Related Art A traction control system (TCS) that controls engine driving force (traction) by cutting a fuel supply to an engine (fuel cut) or changing an ignition timing (retard) to suppress an acceleration slip of a vehicle has been known. (See Japanese Patent Application Laid-Open Nos. 1-147127 and 62-21421 and Japanese Patent Application No. 2-43836 previously filed by the present applicant).
[0003]
In such a conventional TCS, while the TCS is operating, the number of engine cylinders to be fuel cut to decrease the torque is increased or decreased, the air-fuel ratio correction in the non-fuel cut cylinder is stopped, and the protection of the exhaust purification catalyst is prevented. For this purpose, various fuel supply control methods such as determining the fuel cut condition at the catalyst inlet temperature have been adopted.
[0004]
[Problems to be solved by the invention]
However, the conventional TCS fuel supply control technology has the following problems.
That is, there is known an exhaust gas purifying apparatus provided with a lean NOx catalyst for purifying nitrogen oxides (NOx) in exhaust gas under a lean air-fuel ratio atmosphere using hydrocarbons (HC) in the exhaust gas in an exhaust passage 1 of the engine. However, the conventional fuel supply control technology in the TCS does not consider the NOx conversion performance by the lean NOx catalyst at the time of fuel cut (lean) in the traction control in the one provided with such a lean NOx catalyst. Since this technology is not performed, the conversion efficiency of the lean NOx catalyst cannot be maximized, and the conversion efficiency of NOx during fuel cut is low.
[0005]
In view of the above problems, the present invention relates to an internal combustion engine having a system for controlling driving force (traction) by fuel cut, and an internal combustion engine having a lean NOx catalyst interposed in an exhaust passage. An object of the present invention is to increase the NOx conversion efficiency at the time of fuel cut by executing driving force (traction) control in consideration of the performance of a lean NOx catalyst.
[0006]
[Means for Solving the Problems]
Therefore, the invention according to claim 1 is, as shown in FIG.
In a vehicle internal combustion engine provided with a lean NOx catalyst for purifying nitrogen oxides in exhaust gas under a lean air-fuel ratio atmosphere by using hydrocarbons in the exhaust gas in hydrocarbons,
A slip ratio detecting means A for detecting a slip ratio between a wheel and a road surface of the vehicle,
Operating state detecting means B for detecting an engine operating state;
Catalyst performance detecting means C for detecting the lean NOx catalyst performance;
Basic supply amount calculating means D for calculating a basic supply amount of fuel to the engine based on the engine operating state;
The calculated basic supply amount of fuel is corrected so as to cut off the fuel supply according to the slip ratio to control the engine driving force, and the fuel is supplied according to the catalyst performance detected by the catalyst performance detection means C. Fuel supply amount control means E for setting a supply cut amount;
Fuel supply means F for supplying fuel to the engine according to the output of the fuel supply amount control means E;
It was comprised including.
[0007]
According to the second aspect of the present invention, as shown in FIG.
In a vehicle internal combustion engine provided with a lean NOx catalyst for purifying nitrogen oxides in exhaust gas under a lean air-fuel ratio atmosphere by using hydrocarbons in the exhaust gas in hydrocarbons,
A slip ratio detecting means A for detecting a slip ratio between a wheel and a road surface of the vehicle,
Operating state detecting means B for detecting an engine operating state;
Catalyst performance detecting means C for detecting the lean NOx catalyst performance;
Basic supply amount calculating means D for calculating a basic supply amount of fuel to the engine based on the engine operating state;
Fuel supply amount control means E for controlling the engine driving force by correcting the calculated basic supply amount of fuel so as to cut off the fuel supply according to the slip ratio;
Fuel supply timing calculating means G for calculating the timing of supplying fuel to the engine according to the outputs from the fuel supply amount control means E and the catalyst performance detecting means C;
Fuel supply means F for supplying fuel to the engine based on the output of the fuel supply timing calculation means G;
It was comprised including.
[0008]
According to the third aspect of the present invention, as shown in FIG.
In a vehicle internal combustion engine provided with a lean NOx catalyst for purifying nitrogen oxides in exhaust gas under a lean air-fuel ratio atmosphere by using hydrocarbons in the exhaust gas in hydrocarbons,
A slip ratio detecting means A for detecting a slip ratio between a wheel and a road surface of the vehicle,
Operating state detecting means B for detecting an engine operating state;
Catalyst performance detecting means C for detecting the lean NOx catalyst performance;
Basic supply amount calculating means D for calculating a basic supply amount of fuel to the engine based on the engine operating state;
The calculated basic supply amount of fuel is corrected so as to cut off the fuel supply according to the slip ratio to control the engine driving force, and the cutoff amount of the fuel supply is set according to the catalyst performance. An amount control means E;
Fuel supply timing calculating means G for calculating the timing of supplying fuel to the engine based on outputs from the fuel supply amount control means E and the catalyst performance detecting means C;
Fuel supply means F for supplying fuel to the engine based on the output of the fuel supply timing calculation means G;
It was comprised including.
[0009]
The invention according to claim 4 is
The catalyst performance detecting means detects the conversion efficiency of the lean NOx catalyst corresponding to the intake air amount to the engine and the lean NOx catalyst inlet temperature.
The invention according to claim 5 is
In the fuel supply amount control means, the configuration for setting the cut amount of fuel supply according to the catalyst performance is such that the lower limit fuel cut cylinder number is determined in accordance with the performance of the lean NOx catalyst, and the lower limit fuel cut cylinder number is determined. In addition, the actual number of fuel cut cylinders for which the fuel cut is executed is determined.
[0010]
The invention according to claim 6 is
When the fuel supply timing calculating means corrects the fuel supply so as to cut off the fuel supply and controls the engine driving force, the fuel supply timing calculating means calculates the time at which the amount of HC emission increases as the time at which fuel is supplied to the engine.
The invention according to claim 7 is
The slip ratio detecting means is configured to calculate a slip ratio from the driving wheel rotation speed and the non-driving wheel rotation speed of the vehicle.
[0011]
[Action]
In the invention according to claim 1, when controlling the engine driving force by correcting the basic supply amount of fuel so as to cut off the fuel supply in accordance with the slip ratio, the catalyst performance detected by the catalyst performance detection means is reduced. Accordingly, the cut amount of the fuel supply is set, and control is performed in consideration of the lean NOx catalyst performance at the time of the fuel supply cut [lean]. For example, the conversion efficiency of the lean NOx catalyst is maximized, and the NOx at the time of the fuel supply cut is reduced. Conversion efficiency can be increased.
[0012]
According to the second aspect of the present invention, the output from the fuel supply amount control means and the catalyst performance detection means for controlling the engine driving force by correcting the basic supply amount of fuel so as to cut off the fuel supply in accordance with the slip ratio. The timing of supplying fuel to the engine is calculated in accordance with the following equation, the fuel supply timing is set in accordance with the catalyst performance, and control is performed in consideration of lean NOx catalyst performance at the time of fuel supply cut [lean]. It is possible to maximize the conversion efficiency of the catalyst and increase the NOx conversion efficiency when the fuel supply is cut.
[0013]
According to the third aspect of the present invention, when controlling the engine driving force by correcting the basic supply amount of fuel so as to cut off the fuel supply in accordance with the slip ratio, the catalyst performance detected by the catalyst performance detecting means is reduced. The fuel supply cut amount is set accordingly, and the timing of supplying fuel to the engine is calculated according to the output from the fuel supply amount control means and the catalyst performance detection means. The timing is set, and for example, the conversion efficiency of the lean NOx catalyst can be more effectively maximized, and the NOx conversion efficiency at the time of fuel supply cut can be further increased.
[0014]
According to the fourth aspect of the present invention, the conversion efficiency of the lean NOx catalyst corresponding to the intake air amount to the engine and the lean NOx catalyst inlet temperature is detected as the lean NOx catalyst performance.
According to the fifth aspect of the invention, the lower limit fuel cut cylinder number is determined in accordance with the performance of the lean NOx catalyst, and the actual fuel cut cylinder number for executing the fuel cut in accordance with the lower limit fuel cut cylinder number is determined. Then, the cut amount of the fuel supply according to the catalyst performance is set.
[0015]
According to the sixth aspect of the invention, when controlling the engine driving force by correcting the fuel supply so as to cut off the fuel supply, the time when the HC emission increases is calculated as the time when the fuel is supplied to the engine.
In the seventh aspect of the invention, the slip ratio is calculated from the driving wheel rotation speed and the non-driving wheel rotation speed of the vehicle.
[0016]
【Example】
Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.
FIG. 4 is a system diagram of the entire vehicle.
In an internal combustion engine (hereinafter referred to as an engine) 1, intake air is supplied from an air cleaner 2 to each cylinder from each branch of an intake manifold 5 through an intake pipe 3 and a throttle chamber 4, and fuel is injected by an injector (fuel supply means) 6. Mixed with the intake air.
[0017]
An ignition plug 7 is mounted on each cylinder of the engine 1, and a high-voltage pulse from an ignition coil 10 is supplied to the ignition plug 7 at a timing when power is supplied to a power transistor 9 via a distributor 8.
The air-fuel mixture in the cylinder is ignited and exploded by the discharge of the ignition plug 7, becomes exhaust, and passes through the exhaust pipe 11, using hydrocarbons (HC) in the exhaust to remove nitrogen oxides (NOx) in the exhaust with a lean air-fuel ratio. The gas is purified by a catalytic converter 12 having a lean NOx catalyst for purifying under an atmosphere, and discharged outside.
[0018]
The power of the engine 1 is transmitted to the drive shaft of the vehicle via the transmission 13 to drive the drive wheels.
The flow rate of the intake air is detected by an air flow meter 15 and controlled by a throttle valve 16 in the throttle chamber 4. The fully closed position of the throttle valve 16 is detected by a throttle valve switch 17, and the crank angle of the engine 1 is detected by a crank angle sensor 18 built in the distributor 8.
[0019]
Knocking occurring in engine 1 is detected by knock sensor 19, and the temperature of cooling water is detected by water temperature sensor 20.
The shift position of the transmission 13 is detected by a reverse switch 23, and the neutral position of the transmission 13 is detected by a neutral switch 24.
The rotation speed of the driving wheels of the vehicle is detected by a driving wheel speed sensor (driving wheel rotation speed detecting means) 25, and the rotation speed of the driven wheels (non-driving wheels) is driven wheel speed sensor (non-driving wheel rotation speed detecting means). 26.
[0020]
The exhaust gas temperature at the inlet of the catalytic converter 12 is detected by a catalyst inlet temperature sensor 27, and the catalyst bed temperature of the catalytic converter 12 is detected by a catalyst bed temperature sensor 28.
The catalyst inlet temperature sensor 27 and the catalyst bed temperature sensor 28 both constitute catalyst temperature detecting means.
Reference numeral 31 denotes an auxiliary air control valve, 32 denotes an air regulator, 33 denotes an air conditioner and heating solenoid valve, 34 denotes a negative pressure control valve, and 35 denotes a fuel pump.
[0021]
Signals from the sensors 15, 17 to 28 are input to a control unit 40. The control unit 40 has functions as slip ratio calculation means, supply amount calculation means, and ignition timing control means. It consists of. The control unit 49 performs engine ignition timing control, fuel supply control, and vehicle traction control based on the input signals.
[0022]
FIG. 5 is a block diagram of a part of the control performed by the control unit 40 that realizes the function of ignition timing control. In this figure, a multiplexer 41 switches each signal from an air flow meter 15, a water temperature sensor 20, an oxygen sensor 21 and a knock sensor 19 according to the operation of a timer 42 and allows the signal to pass therethrough. After being converted into a signal, it is input to the CPU 44.
[0023]
On the other hand, the signal from the crank angle sensor 18 is counted by the counter 46 by the operation of the timer 45, and a signal corresponding to the number of inputs per unit time is input to the CPU 44 as an engine speed signal. The CPU 44 sends and receives signals to and from the memory 47, calculates an ignition timing suitable for the operating state based on the various signals, and outputs the calculation result to the output circuit 48. The reference angle signal from the crank angle sensor 18 is also input to the output circuit 48, and when it matches the calculated ignition timing, an ignition signal is output to the ignition coil 10 via the power transistor 9, whereby the ignition signal is output via the distributor 3. As a result, the spark plug 7 of a predetermined cylinder discharges and ignites the air-fuel mixture.
[0024]
The air flow meter 15, the throttle valve switch 17, the crank angle sensor 18, the water temperature sensor 20, and the oxygen sensor 21 constitute an operation state detecting means 51, and the ignition plug 7, the distributor 8, the power transistor 9, and the ignition coil 10 The means 52 is constituted.
Next, an operation based on such a configuration will be described.
[0025]
First, the fuel injection control will be described. The basic fuel injection amount Tp is calculated based on the detected intake air amount Qa and the engine speed N.
Tp = K · Qa / N─ (1)
However, after calculating K from a constant expression, the basic fuel injection amount Tp is corrected as in the following expression (2) based on the detected coolant temperature and the oxygen concentration in the exhaust gas, and the fuel injection amount Ti Is calculated.
Ti = Tp × (1 + K _TW + K _AS + K _AI + K _ACC + K _DEC ) × K _FC + T _s (2)
Where K _TW ; water temperature increase correction coefficient K _AS ; start and post-start increase correction coefficient K _AI ; idle increase correction coefficient K _ACC ; acceleration correction coefficient K _DEC ; deceleration correction coefficient K _FC ; fuel cut correction coefficient T _s ; battery A pulse signal corresponding to the calculated fuel injection amount Ti is output to the injector 6 for the voltage correction, and fuel injection control is performed.
[0026]
During the fuel injection control, a driving force control routine shown in the flowcharts of FIGS. 6 and 7 is executed.
That is, in this flow chart, (in the figure. Similarly abbreviated as S1) In step 1, the actual engine rotational speed N is detected, reads various signals such as the vehicle speed V _SP, the shift stage which is detected at step 2 Is determined to be the reverse gear. If it is determined that the vehicle is in the reverse gear, the process proceeds to step 3, and if it is determined that the vehicle is not in the reverse gear, that is, it is the forward gear, the process proceeds to step 8. In step 3, a second fuel cut rotation speed N _MAXR at the time of reverse is set as the second set rotation speed, and at step 4, a second fuel cut vehicle speed V _SPMAXR at the time of reverse is set as the second set vehicle speed. .
[0027]
On the other hand, in step 8, the first fuel cut rotation speed N _MAX during forward _running as the first set rotation speed is set, and in step 9, the first fuel cut vehicle speed V _SPMAX during forward _running as the first set vehicle speed is set. Set. Here, the second fuel cut rotation speed N _MAXR is set to be smaller than the first fuel cut rotation speed N _MAX , and the second fuel cut vehicle speed V _SPMAXR is set smaller than the first fuel cut vehicle speed V _SPMAX. Is set.
[0028]
In step 5, it is determined whether or not the engine rotation speed N exceeds the second fuel cut rotation speed N _MAXR . If it is determined that the rotation speed N exceeds the second fuel cut rotation speed N _MAXR , the process proceeds to step 20 without passing through step 6, and does not exceed. When the determination is made, the process proceeds to step 6. In step 6, it is determined whether or not the vehicle speed V _SP exceeds a second fuel cut vehicle speed V _SPMAXR, if it is determined to be above the flow proceeds to step 20, when it is judged not exceed Step 12 Proceed to.
[0029]
Therefore, when the shift stage is in reverse gear, when the engine rotational speed N is when exceeding the second fuel cut-off rotation speed _{N MAXR,} or the vehicle speed _{V SP} exceeds a second fuel cut vehicle speed _{V SPMAXR,} later Then, the traction control after step 20 is executed.
On the other hand, when the shift stage is at the forward stage, it is determined whether or not the engine rotational speed N exceeds the first fuel cut-off rotation speed N _MAX in step 10, if it is determined to be above the process proceeds to step 20 If it is determined that the distance has not been exceeded, the routine proceeds to step 12. In step 12, the fuel injection control by the injector is continued without performing the fuel cut.
[0030]
Therefore, when the shift stage is in forward gear, when exceeding the first fuel cut-off rotation speed N _MAX of the engine rotational speed N is set larger than the second fuel cut-off rotation speed N _MAXR, or the vehicle speed V _SP is second When the vehicle speed exceeds a first fuel cut vehicle speed V _SPMAX set to be _higher than the fuel cut vehicle speed V _SPMAXR , traction control from step 20 described later is executed.
[0031]
Next, traction control after step 20 will be described.
That is, in step 20, the driving wheel speed V _DW and the driven wheel speed _VPW are measured respectively. Next, in step 21, the slip ratio _SL is calculated based on the following equation.
_{S L = (V DW -V PW} ) / V DW
In step 22, the amount Qa of intake air to the engine is measured by the air flow meter. In step 23, to measure the catalyst inlet temperature T _in the catalyst inlet temperature sensor.
[0032]
Then, in step 24, to set the lower fuel-cut number _{N LL} from the intake air quantity Qa and the catalyst inlet temperature _{T in.}
The setting of the lower limit fuel cut cylinder number N _LL is performed as follows.
Conversion efficiency of the lean NOx catalyst changes in accordance with the intake air quantity Qa and the catalyst inlet temperature T _in. 8 shows an example of this, generally, the intake air quantity Qa is small, the catalyst inlet temperature T _in is large conversion efficiency at around 350 ° C. Further, the generation amount of NOx decreases in proportion to the number of fuel cut cylinders.
[0033]
Therefore, when setting a lower fuel-cut number _{N LL} from the intake air quantity Qa and the catalyst inlet temperature _{T in,} as shown in FIG. 9, the intake air quantity Qa is small, the catalyst inlet temperature _{T in} is in the vicinity of 350 ° C , The lower limit fuel cut cylinder number N _LL is set to be small, and is set to increase as the distance from the cylinder becomes further away.
After setting the lower fuel-cut number N _LL in step 24 in this manner, in step 25, compared with the allowable value and the slip ratio S _L, the slip ratio S _L is less than the allowable value, the slip is allowed If so, the _routine proceeds to step 31, where the number of fuel cut cylinders N _FCCY is set to 0, and the _routine returns to step 1.
[0034]
On the other hand, if the slip ratio _SL is equal to or larger than the allowable value and the slip is not allowed, the process proceeds to step 26, where the present slip ratio _SL and the previous slip ratio _SL-1 are compared, and _SL > S If it is _L-1 , the process proceeds to step 27, in which the number of fuel cut cylinders N _FCCY is increased by one (N _FCCY = N _FCCY +1), and fuel cut is executed for the determined number of fuel cut cylinders N _FCCY . I do.
[0035]
If _{S L} ≦ S _L-1, the routine proceeds to step 28, the fuel-cut number _{N FCCY} reduces one _{1 (N FCCY = N FCCY -1} ), the process proceeds to step 29.
In step 29, the number of fuel cut cylinders N _FCCY is _compared with the set lower limit number of fuel cut cylinders N _LL, and if N _FCCY ≦ N _LL , the _routine proceeds to step 30, where N _FCCY is _set to N _LL and (N _FCCY). = N _LL ), the fuel cut is executed for the determined number of fuel cut cylinders N _FCCY .
[0036]
If N _FCCY > N _LL , the fuel cut is executed for the fuel cut cylinder number N _FCCY determined in step 28.
According to the above embodiment, in response to the conversion efficiency of the lean NOx catalyst at that time, to determine the lower limit fuel-cut number N _LL, the actual fuel cutoff number cylinders to perform fuel cut to fit the N _LL Since _NFCCY is determined, the emission amount of NOx can be suppressed to the minimum value.
[0037]
Next, another embodiment of the present invention will be described.
In this embodiment, the timing of the fuel injection timing at the time of traction control is set when the amount of HC emission is large, and the conversion efficiency of the lean NOx catalyst is improved.
That is, the NOx conversion efficiency is proportional to the HC / NO ratio as shown in FIG. Therefore, under the lean condition (at the time of traction control), if the HC discharge amount is increased, the conversion efficiency of NOx increases, which is advantageous for NOx reduction.
[0038]
On the other hand, the HC discharge amount increases when the fuel injection timing reaches the intake valve opening timing as shown in FIG. However, the stability of the engine deteriorates. For this reason, as shown in FIG. 11, conventionally, the injection timing is set at a place where the engine stability is high just before the intake valve is opened.
Therefore, in this embodiment, the fuel injection timing is set at the intake valve opening timing to increase the HC, so that the NOx conversion efficiency is increased, which is advantageous for NOx reduction. In this case, the stability of the engine naturally deteriorates, but there is no problem because it is during traction control.
[0039]
Such control will be described with reference to the flowcharts of FIGS.
In this flowchart, steps 1 to 12, and steps 20, 21, 25, 26, 27, 28, and 31 are the same as those in the previous embodiment, and thus description thereof will be omitted, and only differences will be described.
If the conditions of Steps 12 and 31 indicate that the fuel cut is not to be performed, the process proceeds to Step 33 to set the usual fuel injection timing which has been conventionally performed.
[0040]
On the other hand, when the conditions for performing the fuel cut in step 27 and step 28 are satisfied, the routine proceeds to step 32, in which the fuel injection timing is set to the intake valve opening timing instead of the normal fuel injection timing.
According to the above embodiment, the fuel injection timing is set at the intake valve opening timing to increase the HC and increase the NOx conversion efficiency, so that the NOx reduction can be effectively achieved.
[0041]
In the embodiment shown in the flowcharts of FIGS. 6 and 7, the lower limit fuel cut cylinder number N _LL is determined according to the conversion efficiency of the lean NOx catalyst, and the actual fuel cut is executed in accordance with the N _LL. take the method of determining the fuel-cut number N _FCCY, in the embodiment shown in the flowchart of FIG. 12 and FIG. 13, by setting the fuel injection timing increases the HC to intake valve opening timing, the conversion efficiency of NOx Although the method of increasing the pressure is adopted, it is possible to more effectively reduce NOx by employing these methods at the same time.
[0042]
The control contents of this embodiment are as shown in the flowcharts of FIGS. 14 and 15, and are obtained by adding steps 32 and 33 of the injection timing setting to the flowcharts of FIGS.
[0043]
【The invention's effect】
As described above, according to the first aspect of the present invention, the cut amount of the fuel supply is set in accordance with the catalyst performance, and control is performed in consideration of the lean NOx catalyst performance at the time of the fuel supply cut [lean]. For example, it is possible to maximize the conversion efficiency of the lean NOx catalyst and to increase the NOx conversion efficiency when the fuel supply is cut.
[0044]
According to the second aspect of the present invention, the fuel supply timing is set in accordance with the catalyst performance to perform control in consideration of the lean NOx catalyst performance at the time of fuel supply cut [lean]. It is possible to maximize the conversion efficiency of NOx and to increase the NOx conversion efficiency when the fuel supply is cut.
According to the third aspect of the present invention, the fuel supply cut amount is set in accordance with the catalyst performance, and the fuel supply timing is set in accordance with the catalyst performance, so that the fuel supply cut (lean) is performed. Since the control is performed in consideration of the lean NOx catalyst performance, for example, the conversion efficiency of the lean NOx catalyst can be maximized more effectively, and the NOx conversion efficiency when the fuel supply is cut can be further increased.
[0045]
According to the fourth aspect of the present invention, the conversion efficiency of the lean NOx catalyst corresponding to the intake air amount to the engine and the lean NOx catalyst inlet temperature can be detected as the lean NOx catalyst performance.
According to the fifth aspect of the present invention, the lower limit fuel cut cylinder number is determined in accordance with the performance of the lean NOx catalyst, and the actual fuel cut cylinder number for executing the fuel cut in accordance with the lower limit fuel cut cylinder number is determined. Once determined, the cutoff amount of fuel supply according to the catalyst performance can be set.
[0046]
According to the sixth aspect of the present invention, when the engine driving force is controlled by correcting the fuel supply so as to be cut off, the time at which the HC emission increases can be calculated as the time at which fuel is supplied to the engine.
According to the seventh aspect of the invention, the slip ratio can be calculated from the driving wheel rotation speed and the non-driving wheel rotation speed of the vehicle.
[Brief description of the drawings]
FIG. 1 is a block diagram of the invention according to claim 1; FIG. 2 is a block diagram of the invention according to claim 2; FIG. 3 is a block diagram of the invention according to claim 3; FIG. 5 is a block diagram of a part for realizing the function of ignition timing control in the control performed by the control unit; FIG. 6 is a diagram illustrating the control content of the embodiment of the invention according to claim 1; FIG. 7 is a flow chart for explaining the control contents of the embodiment of the invention according to claim 1. FIG. 8 is a characteristic diagram of the conversion efficiency of the lean NOx catalyst corresponding to the intake air amount and the catalyst inlet temperature. FIG. 10 is a characteristic diagram showing the relationship between the HC / NO ratio and the NOx conversion efficiency corresponding to the amount and the catalyst inlet temperature. FIG. 11 is a characteristic diagram showing the relationship between the HC / NO ratio and the NOx conversion efficiency. FIG. 12 is a characteristic diagram showing the relationship with the degree. FIG. 13 is a flowchart for explaining the control contents of the embodiment of the invention according to claim 2; FIG. 13 is a flowchart for explaining the control contents of the embodiment of the invention according to claim 2; FIG. 14 is an embodiment of the invention according to claim 3; FIG. 15 is a flowchart for explaining control contents. FIG. 15 is a flowchart for explaining control contents for the embodiment of the invention according to claim 3.
1 engine 6 injector 6
12 Catalytic converter 15 Air flow meter 18 Crank angle sensor 25 Drive wheel speed sensor 26 Driven wheel speed sensor 27 Catalyst inlet temperature sensor 40 Control unit 49 Control unit

Claims (7)

In a vehicle internal combustion engine provided with a lean NOx catalyst for purifying nitrogen oxides in exhaust gas under a lean air-fuel ratio atmosphere by using hydrocarbons in the exhaust gas in hydrocarbons,
A slip ratio detecting means for detecting a slip ratio between a vehicle wheel and a road surface,
Operating state detecting means for detecting an engine operating state;
Catalyst performance detection means for detecting the lean NOx catalyst performance;
Basic supply amount calculating means for calculating a basic supply amount of fuel to the engine based on the engine operating state;
The calculated basic supply amount of fuel is corrected so as to cut off the fuel supply according to the slip ratio to control the engine driving force, and the fuel supply is controlled according to the catalyst performance detected by the catalyst performance detection means. Fuel supply amount control means for setting the cut amount of
Fuel supply means for supplying fuel to the engine according to the output of the fuel supply amount control means,
A fuel supply control device for an internal combustion engine, comprising: In a vehicle internal combustion engine provided with a lean NOx catalyst for purifying nitrogen oxides in exhaust gas under a lean air-fuel ratio atmosphere by using hydrocarbons in the exhaust gas in hydrocarbons,
A slip ratio detecting means for detecting a slip ratio between a vehicle wheel and a road surface,
Operating state detecting means for detecting an engine operating state;
Catalyst performance detection means for detecting the lean NOx catalyst performance;
Basic supply amount calculating means for calculating a basic supply amount of fuel to the engine based on the engine operating state;
Fuel supply amount control means for controlling the engine driving force by correcting the calculated basic supply amount of fuel so as to cut off the fuel supply according to the slip ratio,
Fuel supply timing calculation means for calculating the timing of supplying fuel to the engine according to the output from the fuel supply amount control means and the catalyst performance detection means,
Fuel supply means for supplying fuel to the engine based on the output of the fuel supply timing calculation means,
A fuel supply control device for an internal combustion engine, comprising: In a vehicle internal combustion engine provided with a lean NOx catalyst for purifying nitrogen oxides in exhaust gas under a lean air-fuel ratio atmosphere by using hydrocarbons in the exhaust gas in hydrocarbons,
A slip ratio detecting means for detecting a slip ratio between a vehicle wheel and a road surface,
Operating state detecting means for detecting an engine operating state;
Catalyst performance detection means for detecting the lean NOx catalyst performance;
Basic supply amount calculating means for calculating a basic supply amount of fuel to the engine based on the engine operating state;
The calculated basic supply amount of fuel is corrected so as to cut off the fuel supply according to the slip ratio to control the engine driving force, and the cutoff amount of the fuel supply is set according to the catalyst performance. Volume control means;
Fuel supply timing calculation means for calculating the timing of supplying fuel to the engine based on the outputs from the fuel supply amount control means and the catalyst performance detection means,
Fuel supply means for supplying fuel to the engine based on the output of the fuel supply timing calculation means,
A fuel supply control device for an internal combustion engine, comprising: 2. The fuel supply control device for an internal combustion engine according to claim 1, wherein the catalyst performance detecting means detects a conversion efficiency of the lean NOx catalyst corresponding to an intake air amount to the engine and a lean NOx catalyst inlet temperature. In the fuel supply amount control means, the configuration in which the fuel supply cut amount is set in accordance with the catalyst performance is such that the lower limit fuel cut cylinder number is determined in accordance with the performance of the lean NOx catalyst, and the lower limit fuel cut cylinder number is determined. 4. The fuel supply control device for an internal combustion engine according to claim 1, wherein the actual number of fuel cut cylinders for which the fuel cut is executed is determined. 4. The fuel supply timing calculating means calculates a time at which the amount of HC emission increases as a time at which fuel is supplied to the engine when controlling the engine driving force by correcting the fuel supply so as to cut off the fuel supply. A fuel supply control device for an internal combustion engine according to claim 1. The fuel supply control device for an internal combustion engine according to any one of claims 1 to 6, wherein the slip ratio detecting means is configured to calculate a slip ratio from a driving wheel rotation speed and a non-driving wheel rotation speed of the vehicle. .

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