JP3632325B2 - Engine torque control device - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a technique for mitigating torque shock while avoiding the influence of an exhaust gas temperature increase of an exhaust purification catalyst at the time of shifting of an automatic transmission.
[0002]
[Prior art]
Conventionally, as a shift shock mitigation technique at the time of shifting of an automatic transmission for automobiles, by controlling any one of engine ignition timing, fuel injection amount, and throttle valve opening, engine torque is reduced to reduce shifting torque. In this case, a sudden change in transmission output shaft torque is suppressed to alleviate a shift shock (see, for example, JP-A-2-102348).
[0003]
[Problems to be solved by the invention]
However, in such a conventional technique, for example, if the ignition timing is retarded as engine torque reduction control, the exhaust temperature rises and affects the exhaust purification catalyst. For example, if control is performed to stop the fuel supply to some cylinders, the air-fuel ratio becomes lean, the oxygen concentration in the exhaust increases, and the exhaust purification catalyst oxidizes. Excessive influence.
[0004]
If the control is performed to reduce the throttle valve opening, the influence on the exhaust purification catalyst can be avoided, but since the response of the engine torque reduction is slow, it is difficult to sufficiently reduce the shift shock.
The present invention has been made in view of such conventional problems. By combining a plurality of engine controls, an engine torque control that can sufficiently reduce a shift shock while avoiding an influence on an exhaust purification catalyst. An object is to provide an apparatus.
[0005]
[Means for Solving the Problems]
Therefore, the engine torque control device according to the invention of claim 1 is shown in FIG.
A vehicle having a throttle valve control device that controls the opening of a throttle valve interposed in an intake system of the engine to a target value, an exhaust purification catalyst in the exhaust system, and an automatic transmission connected to the output shaft of the engine In
Shift detection means for detecting a shift of the automatic transmission;
When the shift of the automatic transmission is detected, a first engine that decreases the engine torque by decreasing the throttle valve opening so as to meet the required engine torque decrease amount by the throttle valve control device over the entire shift period. Torque reduction control means;
Similarly, when a shift of the automatic transmission is detected, a plurality of engine controls other than the throttle valve opening reduction control are provided at the initial stage of the shift so as to cover the shortage of the engine torque reduction while the increase / decrease in the exhaust temperature is mitigated. A second engine torque reduction control means to be performed in combination;
It is characterized by including.
[0007]
Action / Effect When the shift of the automatic transmission is detected by the shift detection means, the first engine torque reduction control means matches the required engine torque reduction amount over the entire shift period via the throttle valve control device. In this way, the engine torque is reduced by reducing the throttle valve opening.
At the same time, the second engine torque reduction control means combines a plurality of engine controls other than the throttle valve opening reduction control at the beginning of the shift to cover the shortage of engine torque reduction while mitigating the increase and decrease in exhaust temperature. Make it.
[0008]
As a result, a sufficient engine torque reduction can be obtained with good responsiveness at the time of shifting, and a shift shock can be satisfactorily avoided, and the combination of the plurality of engine controls is a combination that reduces the increase / decrease in the exhaust temperature. The influence on the exhaust gas purification catalyst due to can be avoided, and the durability can be ensured .
Further, even if the first engine torque reduction control means starts the reduction control corresponding to the requested engine torque reduction amount simultaneously with the detection of the shift, the intake air amount is reduced and the engine torque actually becomes the requested amount. There is a large response delay until it decreases.
Therefore, in the initial stage of shifting, the second engine torque reduction control means performs a combination of a plurality of engine controls other than the throttle valve opening reduction control. As a result, the engine torque can be reduced with good responsiveness from the beginning of the shift to cover the shortage of engine torque reduction due to the response delay of the throttle valve reduction control. A reduction amount can be secured.
The invention according to claim 2
The second engine torque reduction control means performs a combination of control for stopping fuel supply to some cylinders of the engine at the beginning of shifting and control for increasing fuel supply amount for the remaining cylinders. And
[0009]
Action / Effect
In the initial stage of shifting, the second engine torque reduction control means performs a combination of a plurality of engine controls other than the throttle valve opening reduction control . As a result, the engine torque can be reduced with good responsiveness from the initial stage of shifting by stopping the fuel supply to some cylinders to cover the shortage of engine torque reduction due to response delay in throttle valve reduction control. The required engine torque reduction amount can be ensured only by the decrease control.
[0010]
Here, if the fuel supply to the partial cylinders is stopped and the fuel injection amount of the remaining cylinders is controlled with an amount corresponding to the target air-fuel ratio of each cylinder as it is, the air-fuel ratio of the exhaust as a whole becomes lean and the exhaust gas is exhausted. The oxidation reaction of the purification catalyst becomes excessive and the temperature rise increases. Therefore, by increasing the fuel supply amount of the remaining cylinders, it is possible to avoid the influence on the exhaust purification catalyst by bringing the air-fuel ratio of the exhaust of the entire cylinder closer to the target air-fuel ratio, and ensuring durability. it can.
[0011]
The invention according to claim 3
The second engine torque reduction control means performs a combination of retarding control of the ignition timing of the engine and increasing control of the fuel supply amount at the beginning of shifting.
[0012]
Action / Effect Similarly to the invention according to claim 2, when the first engine torque reduction control means starts controlling the throttle valve opening in accordance with the required engine torque reduction amount, the engine torque decreases at the beginning of the shift. Cause a delay in response.
Therefore, the engine torque is retarded by the second engine torque reduction control means in the early stage of the shift, thereby reducing the engine torque with good responsiveness, and the shortage due to the response delay of the throttle valve opening reduction control. The required engine torque reduction amount can be ensured only by the throttle valve opening reduction control in the latter half of the shift.
[0013]
Further, the effect of increasing the exhaust gas temperature by the ignition timing retarding control can be mitigated by the effect of reducing the exhaust gas temperature by enriching the air-fuel ratio by performing the increase control of the fuel supply amount in parallel. The influence on the exhaust purification catalyst can be avoided.
The invention according to claim 4
The second engine torque reduction control means controls the retarding of the ignition timing of the engine at the beginning of the shift, controls to stop the fuel supply to some cylinders of the engine, and controls to increase the fuel supply amount of the remaining cylinders. Control is performed in combination.
[0014]
Action / Effect Similarly to the above, the first engine torque reduction control means performs the control corresponding to the required engine torque reduction amount by the first engine torque reduction control means, while the second engine torque reduction control means at the initial stage of the shift, The engine timing is reduced with good responsiveness by ignition timing retardation control and fuel supply stop control of some cylinders, and the shortage due to response delay of the throttle valve opening reduction control is covered. The exhaust temperature increasing action by the fuel supply stop control of the partial cylinders can be mitigated by the exhaust temperature reducing action by increasing the fuel supply amount of the remaining cylinders, and the influence on the exhaust purification catalyst can be avoided.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
In FIG. 2 showing the configuration of the present embodiment, an automatic transmission 2 is connected to the output side of the engine 1. The automatic transmission 2 includes a torque converter 3 interposed on the output side of the engine 1, a gear-type transmission 4 connected via the torque converter 3, and various transmission elements in the gear-type transmission 4. And a hydraulic actuator 5 that performs a releasing operation. The hydraulic pressure for the hydraulic actuator 5 is ON / OFF controlled via various electromagnetic valves (not shown).
[0022]
The engine 1 is provided with an ignition plug 21 that is mounted in a combustion chamber and ignites, and each intake port of the intake manifold is provided with a fuel injection valve 22 that injects fuel for each cylinder. Upon receiving the command, ignition control is performed at a predetermined ignition timing, and injection control is performed at a predetermined injection timing. A fuel injection valve may be provided so that fuel is directly injected into the combustion chamber of each cylinder.
[0023]
Further, a throttle sensor 8 for detecting the opening TVO of the throttle valve 7 of the intake system of the engine 1 is provided, and a throttle for controlling the throttle valve 7 to a target opening upon receiving a command from the control unit 6. An actuator (throttle valve control device) 23 is provided.
Further, a crank angle sensor 9 is provided on the crankshaft of the engine 1 or a shaft that rotates in synchronization therewith. The signal from the crank angle sensor 9 is, for example, a pulse signal for each reference crank angle, and the engine speed N is calculated from the cycle.
[0024]
Further, the automatic transmission 2 is provided with a gear position sensor 11 that detects the gear position and a vehicle speed sensor 12 that detects the vehicle speed VSP through detection of the rotational speed of the output shaft 10. In addition, a water temperature sensor 13 for detecting the coolant temperature of the engine is provided.
The control unit 6 sets the target throttle opening based on the opening of the accelerator pedal operated by the driver, the slip ratio of the vehicle tire, and the like, and controls the opening of the throttle valve via the throttle actuator 23. To do. On the other hand, in the state where the select lever is in the D range based on the operation position signal of the select lever operated by the driver, the first to fourth shift positions are automatically set according to the throttle valve opening TVO and the vehicle speed VSP, and the hydraulic actuator 5 is used to perform gear shift control for controlling the gear type transmission 4 to its gear shift position.
[0025]
The exhaust passage 14 of the engine 1 is provided with an exhaust purification catalyst (three-way catalyst) 15 for purifying pollutants in the exhaust.
Next, engine torque reduction control at the time of shifting in the present embodiment will be described.
FIG. 3 is a flowchart showing a routine of engine torque reduction control according to the first embodiment (embodiment of the invention according to claim 2).
[0026]
Step (denoted as S in the figure. The same applies hereinafter) At 1, it is determined whether or not the shift of the automatic transmission 2 has been started.
If it is determined that the shift is started, the process proceeds to step 2 where the engine rotational speed N calculated based on the signal from the crank angle sensor 9 is read and the gear position G of the transmission, the water temperature is read from the gear position sensor 11. The coolant temperature Tw detected by the sensor 13 is read.
[0027]
In step 3, the engine torque reduction amount required at the time of the shift is calculated based on the current driving state estimated from the various detection values.
In step 4, a throttle valve opening TVOa corresponding to the required engine torque reduction amount is calculated.
In step 5, a torque reduction response delay time t for the throttle valve opening reduction control is calculated. This is due to the response delay of intake.
[0028]
In step 6, a drive signal is output to the throttle actuator 23 to control the throttle valve 7 to the target opening TVOa. Thereby, engine torque reduction control for reducing the throttle valve opening is started. The function of step 6 corresponds to first engine torque reduction control means.
In step 7, it is determined whether or not the torque reduction response delay time t has elapsed after the start of shifting.
[0029]
Before the torque reduction response delay time t elapses, the routine proceeds to step 8, where fuel injection from the fuel injection valves 22 of half of all cylinders is stopped and fuel injection from the fuel injection valves 22 of the remaining cylinders is stopped. Control is performed to increase the amount so that the air-fuel ratio of exhaust in the entire cylinder approaches the target air-fuel ratio. Thus, by stopping the fuel injection of the half cylinders, it is possible to cover the response delay of the engine torque reduction by the throttle valve opening reduction control. Further, the exhaust gas temperature increase effect due to leaning of the air-fuel ratio of the exhaust gas when the fuel injection is stopped is mitigated by the exhaust temperature reduction effect of the air-fuel ratio enrichment due to the increase in the fuel injection amount of the remaining cylinders, and the exhaust purification catalyst 15 It is possible to suppress deterioration and to ensure durability. The function of step 8 corresponds to second engine torque reduction control means.
[0030]
In step 9, it is determined whether or not the shift has been completed. When it is determined that the shift has not been completed, the process returns to step 1 and the same control is repeated. Accordingly, the opening degree of the throttle valve 7 is returned to the opening degree before the shift, and the normal control is restored.
If it is determined in step 7 that the torque reduction response delay time t has elapsed after the start of shifting, the process proceeds to step 11 to cancel the fuel injection stop and fuel injection amount increase control for some cylinders, After returning to the uniform normal fuel injection amount control, the routine proceeds to step 9. That is, only the reduction control of the throttle valve 7 is performed in the latter stage of the shift, and thereby the required engine torque reduction amount can be satisfied.
[0031]
The state of the first embodiment is shown in the time chart of FIG.
Next, a routine for engine torque reduction control according to the second embodiment (embodiment of the invention according to claim 3) will be described with reference to the flowchart of FIG.
Since Step 1 to Step 7, Step 9, and Step 10 are the same as those in FIG.
[0032]
If it is determined in step 7 that the torque reduction response delay time t has not elapsed after the start of shifting, the process proceeds to step 21 where the ignition timing of the engine 1 is retarded and the fuel injection amount is increased.
That is, the engine torque reduction control with good responsiveness is controlled by retarding the ignition timing for the response delay of the engine torque reduction due to the throttle valve opening reduction control at the initial stage of gear shift that occurs in the same manner as in the first embodiment. It can be covered by doing. Further, the exhaust temperature increasing action by the ignition timing retarding control can be mitigated by the exhaust temperature reducing action of the air-fuel ratio enrichment by increasing the fuel injection amount, thereby suppressing the deterioration of the exhaust purification catalyst 15 and ensuring the durability. The function of step 21 corresponds to second engine torque reduction control means.
[0033]
When it is determined in step 7 that the torque reduction response delay time t has elapsed, the routine proceeds to step 22 where the ignition timing and the fuel injection control are returned to the normal control before the shift.
The state of the second embodiment is shown in the time chart of FIG.
Next, the routine for engine torque reduction control according to the third embodiment (embodiment of the invention according to claim 4) will be described with reference to the flowchart of FIG.
[0034]
Since Step 1 to Step 7, Step 9, and Step 10 are the same as those in FIG.
When it is determined in step 7 that the torque reduction response delay time t has not elapsed after the start of shifting, the process proceeds to step 31 where the ignition timing is retarded and the fuel injection valves 22 of the cylinders that are half of all the cylinders are controlled. The control for stopping the fuel injection and the control for increasing the fuel injection amount from the fuel injection valves 22 of the remaining cylinders to bring the air-fuel ratio of the exhaust of the entire cylinder closer to the target air-fuel ratio are performed. Thereby, the retard control of the ignition timing and the fuel injection of the half cylinder are stopped, so that the shortage of the engine torque due to the throttle valve opening reduction control can be covered. Further, the exhaust temperature increasing action by the ignition timing retarding control and the fuel injection stop control is mitigated by the exhaust temperature reducing action by increasing the fuel injection amount of the remaining cylinders, thereby suppressing the deterioration of the exhaust purification catalyst 15 and improving the durability. It can be secured. The function of step 31 corresponds to second engine torque reduction control means.
[0035]
When it is determined in step 7 that the torque reduction response delay time t has elapsed, the routine proceeds to step 32, where the ignition timing and the fuel injection control are returned to the normal control before the shift .
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration / function of the present invention.
FIG. 2 is an overall system configuration diagram of an embodiment of the present invention.
FIG. 3 is a flowchart of an engine torque reduction control routine according to the first embodiment.
FIG. 4 is a time chart showing the state of the embodiment.
FIG. 5 is a flowchart of an engine torque reduction control routine according to a second embodiment.
FIG. 6 is a time chart showing the state of the embodiment.
FIG. 7 is a flowchart of an engine torque reduction control routine according to a third embodiment .
[Explanation of symbols]
1 Engine 2 Automatic transmission 3 Torque converter 6 Control unit 8 Throttle sensor 9 Crank angle sensor
14 Exhaust passage
15 Exhaust gas purification catalyst
21 Spark plug
22 Fuel injection valve
23 Throttle actuator

Claims (4)

A vehicle having a throttle valve control device that controls the opening of a throttle valve interposed in an intake system of the engine to a target value, an exhaust purification catalyst in the exhaust system, and an automatic transmission connected to the output shaft of the engine In
Shift detection means for detecting a shift of the automatic transmission;
When the shift of the automatic transmission is detected, a first engine that decreases the engine torque by decreasing the throttle valve opening so as to meet the required engine torque decrease amount by the throttle valve control device over the entire shift period. Torque reduction control means;
Similarly, when a shift of the automatic transmission is detected, a plurality of engine controls other than the throttle valve opening reduction control are provided at the initial stage of the shift so as to cover the shortage of the engine torque reduction while the increase / decrease in the exhaust temperature is mitigated. A second engine torque reduction control means to be performed in combination;
An engine torque control device comprising: The second engine torque reduction control means performs a combination of control for stopping fuel supply to some cylinders of the engine at the beginning of shifting and control for increasing fuel supply amount for the remaining cylinders. The engine torque control device according to claim 1. 2. The engine torque control according to claim 1, wherein the second engine torque reduction control unit performs a combination of a retard control of an ignition timing of the engine and an increase control of a fuel supply amount at an early stage of shifting. apparatus. The second engine torque reduction control means controls the retarding of the ignition timing of the engine at the beginning of the shift, controls to stop the fuel supply to some cylinders of the engine, and controls to increase the fuel supply amount of the remaining cylinders. The engine torque control device according to claim 1, wherein the control is performed in combination .

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