JPS62210251A - Exhaust gas circulating flow control device for engine equipped with automatic transmission - Google Patents

Abstract

PURPOSE:To attempt the improvement of running performance in the range where running performance becomes worst due to the circulating flow of exhaust gas by restraining an exhaust gas circulating quantity when an automatic speed change gear is conditioned to a power running pattern, and furthermore when a step in speed change for low speed is judged in accordance with car speed. CONSTITUTION:A speed change control circuit 53 which detects both a throttle opening sensor 51 and the rotary speed of an input shaft of a torque converter, controls the step in speed change of shift down and shift up in two kinds of power running pattern and an economy pattern which are set by a speed change setting device 55. A signal F is outputted from the speed setting device only when the speed change pattern is conditioned to the economy one, and when the step in speed change is conditioned to a low speed step, a three-way switch-over valve 26 opens an exhaust gas modulator valve 23 to atmosphere through a switch 40 which is closed when the step in speed change is conditioned to a low speed step, for increasing the circulating flow of exhaust gas at the time of acceleration.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to an exhaust gas recirculation control device d for an engine, and in particular to exhaust gas recirculation control for an engine equipped with an automatic transmission that can arbitrarily set a plurality of shift patterns. Regarding the I device.

(Prior Art) Automatic transmissions are widely used as transmissions installed in vehicles together with the engine, and are designed to automatically change gears according to a preset pattern depending on vehicle speed, engine throttle valve opening, etc. However, in recent years, automatic transmissions have been put into practical use in which a plurality of patterns are set as the above-mentioned speed change patterns, and these can be arbitrarily selected and set by a driver's operation.

This type of automatic transmission has a pattern in which upshifts are performed at a relatively low vehicle speed as the vehicle speed increases, a pattern in which this is performed at a relatively high and heavy speed, and a pattern in between. For example, if you select a pattern that shifts up at low vehicle speeds, the engine will be used mainly in the low rotation range, making it possible to drive economically, while if you select a pattern that shifts up at high vehicle speeds, the engine will mainly be used at high rotation speeds. area is used to enable powerful driving.

On the other hand, vehicle engines are equipped with exhaust gas recirculation devices that recirculate part of the exhaust gas into the intake passage or combustion chamber in order to reduce NOx (nitrogen oxides), which is a harmful component in exhaust gas. ing.

In the exhaust gas recirculation system, the amount of NOx emitted increases when the combustion temperature is high, such as when the load is high, so by recirculating inert exhaust gas into the combustion chamber, the combustion temperature is lowered and the NOx generating can is reduced. reduce

If the amount of exhaust gas recirculated is too large, it will deteriorate the engine's operating performance, so it is controlled to the optimum amount depending on the operating condition of the engine. It is shown.

The same bulletin states that in vehicles equipped with automatic transmissions that have a torque converter with a lock-up clutch, when the lock-up clutch is engaged in the low engine speed range,
This is an invention that reduces the recirculation m of exhaust gas,
This invention focuses on the fact that when the lock-up clutch is engaged, the engine speed decreases by the amount of slippage in the torque converter, and in this case, the amount of exhaust gas recirculated increases relatively, improving driving performance. This is to prevent the situation from worsening.

(Problem to be Solved by the Invention) However, even with the control method disclosed in the above publication, the amount of recirculation of exhaust gas is not limited in the low rotation range when the lock-up clutch is not engaged, so the driving performance is still improved. Not done.

In particular, as mentioned above, when multiple shift patterns can be selected and a pattern in which the engine is mainly used at low vehicle speeds is selected, the influence of exhaust gas recirculation is large and the operating condition of the engine deteriorates. was there.

For example, when such a shift pattern is selected, driving performance can be improved by reducing the amount of exhaust gas recirculation, but simply limiting the amount of recirculation results in an increase in NOx emissions. There is.

This invention was made in view of these problems, and its purpose is to suppress the amount of NOx in exhaust gas as much as possible while improving vehicle running performance through exhaust gas recirculation. An object of the present invention is to provide an exhaust gas recirculation control device for an engine with an automatic transmission that can prevent deterioration.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides an exhaust gas recirculation control device for an engine equipped with an automatic transmission. Then, the shift pattern setting means arbitrarily sets a plurality of shift patterns preset according to the vehicle speed, and the gear position of the automatic transmission C is shifted according to the shift pattern set by the shift pattern setting means. It has a transmission control means d for upshifting or downshifting.

It also includes shift pattern determining means e for determining the shift pattern set by the shift pattern setting means I, and gear stage determining means f for determining the gear stage when the vehicle is running.

When the shift pattern determining means e determines a shift pattern for upshifting in the lowest vehicle speed range, and the gear determining means f determines a low gear,
The exhaust gas recirculation correcting means g is provided to limit the amount of exhaust gas recirculated by the exhaust gas recirculation means a.

(Function) According to the exhaust gas recirculation control device for an engine with an automatic transmission configured as described above, the vehicle runs with a shift pattern of upshifting in the lowest vehicle speed range, and also runs in a lower gear in this vehicle speed range. Since the amount of exhaust gas recirculation is corrected only when the exhaust gas is recirculating, it is possible to effectively improve driving performance in the area where the exhaust gas recirculation deteriorates the driving performance the most, and in other areas, the exhaust gas recirculation reduces NOx. The amount generated can be reduced.

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

2 to 6 show an embodiment of an exhaust gas recirculation control device for an engine with an automatic transmission according to the present invention.

Fig. 2 shows the overall structure of the control device, and the control I device is driven and controlled by an exhaust gas recirculation device 20 that recirculates part of the exhaust gas to the intake system and a plurality of arbitrarily set speed change patterns. automatic transmission 8150.

First, the control system of the automatic transmission 50 will be explained. This system includes a throttle opening signal A from a throttle opening sensor 51 that detects the opening of the throttle valve 12 provided in the intake passage 11 of the engine 10. ,
A shift control circuit 53 and a lockup control circuit 54 are provided to which a turbine rotation signal B from a turbine rotation sensor 52 that detects the rotation speed of the input shaft (turbine shaft) of a torque converter in the automatic transmission 50 is input. A shift pattern setting device 55 is also included in this system, and a shift pattern signal C from this device 55 is input to the shift control circuit 53 and lockup control circuit 54.

Here, in this automatic transmission 50, the speed change patterns shown in FIGS.
At least two shift patterns are set as shown in FIG.

That is, the shift pattern shown in FIG. 3 (I) is a power driving pattern (power pattern) in which upshifts are performed in a relatively high vehicle speed range, and the shift pattern shown in FIG. It is an economical driving pattern (economy pattern) that shifts up in the range of Upshifts are performed from 1st to 2nd gear, 2nd to 3rd gear, and 3rd to 4th gear, and as a result, the lock-up area in 3rd and 4th gears is set to a lower vehicle speed side in the economy pattern than in the power pattern. ing. Therefore, when the economy pattern is selected, the engine rotation range is shifted to a lower rotation side than when the power pattern is selected.

A hydraulic control circuit 5 provided in the automatic transmission 5o is connected to a transmission control circuit 53 to which the signals A, B, and C are input.
A shift control signal is output to the first to third solenoids 571 to 573 in the lockup control circuit 5.
4 outputs a lock-up control signal E to the fourth solenoid 574 of the hydraulic control circuit 56.

As a result, depending on the throttle opening degree and turbine rotation speed (this speed is converted to vehicle speed) indicated by signals A and B,
In addition, the gears are automatically switched and set in accordance with the shift patterns shown in FIGS. is turned on and off.

On the other hand, the exhaust gas 3 provided in the engine 10! i! The flow device 20 includes an exhaust gas recirculation passage (hereinafter referred to as an EGR passage) 21 that is led from an exhaust passage (not shown) and connected downstream of the throttle valve 12 in the intake passage 11.
and an exhaust gas recirculation control valve (
It has an EGR valve (hereinafter referred to as an EGR valve) 22 and a modulator valve 23 that supplies control negative pressure to the EGR valve 22. A first end of the intake passage 11 is opened at one end immediately upstream of the throttle valve 12, and intake negative pressure is introduced in accordance with the opening degree of the throttle valve 12. Second negative pressure introduction passages 24 and 25 are connected to the modulator valve 23, the former directly and the latter via the three-way switching valve 26, and between the modulator valve 23 and the EGR valve 22. A control negative pressure supply passage 27 is provided, and an exhaust pressure introduction passage 28 is connected to the modulator valve 23 from a portion immediately upstream of the EGR valve 22 in the EGR passage 21 .

Furthermore, when the economy pattern is selected and set by the shift pattern setting device 55 in the control system of the automatic transmission 50, an economy pattern signal F is sent to the three-way switching valve 26 from the setting device 55. This signal F
The transmission path includes a path where the gear stage of the automatic transmission 50 controlled by the shift control circuit 53 is a low speed (1st and 2nd gear).
A switch 40 is interposed which is activated only when .

When the economy pattern signal F is input to the three-way switching valve 26, the modulator valve 23 of the second negative pressure introduction passage 25
released into the atmosphere.

Here, to explain the configuration of the EGR valve 22 with reference to FIG. 4, the EGR valve 22 is located on the upstream side (
A diaphragm 3 to which the valve body 31 is connected
2, and a spring 33 that presses the diaphragm 32 in the closing direction of the valve body 31.

When negative pressure is introduced into the negative pressure chamber 34 above the diaphragm 32 from the modulator valve 23 through the controlled negative pressure supply passage 27, the diaphragm 32 moves against the spring 33 according to the magnitude of the negative pressure. By being displaced in the direction a, the opening degree of the valve body 31 is adjusted, and the exhaust gas m that is recirculated to the intake passage 11 via the EGR passage 21 is controlled.

Further, the structure of the modulator valve 23 will be explained with reference to FIG. In the pressure chamber 42, the exhaust pressure introduction passage 28 is connected to the exhaust pressure chamber 43, and the negative pressure chamber 4 is connected to the exhaust pressure chamber 43.
2 is provided with a spring 44 that presses the diaphragm 41 toward the exhaust pressure chamber 43.

Roughly speaking, the first negative pressure introduction passage 24 and the control negative pressure supply passage 27 are communicated within the modulator valve 23, and a tip opening of a branch passage 45 branched from the communication portion of both passages 24 and 27. is opposed to the center of the diaphragm 41 within the negative pressure air 42.

This modulator valve 23 operates as follows. First, when negative pressure is introduced into the modulator valve 23 only from the first negative pressure introduction passage 24 (when the opening degree of the throttle valve 12 shown in FIG. 1 is small), this negative pressure is introduced into the branch passage 24.
5 and the exhaust pressure acting on the diaphragm 41 through the exhaust pressure introduction passage 28, the diaphragm 4
1 is displaced in the direction of the arrow against the spring 44 to close the selected opening of the branch passage 45. For this reason, the first
The negative pressure in the negative pressure introduction passage 24 is supplied to the EGR valve 22 through the controlled negative pressure supply passage 27, and accordingly, the EGR valve 2
The second valve body 31 opens the EGR passage 21, and exhaust gas is recirculated from the EGR passage 21 to the intake passage 11 of the engine 1°.

Furthermore, when the valve body 31 of the EGR valve 22 opens the EGR passage 21, the exhaust pressure introduced from the EGR passage 21 through the exhaust pressure introduction passage 28 into the exhaust pressure chamber 43 of the modulator valve 23 decreases. In the modulator valve 23, the diaphragm 41 is displaced in the opposite direction, and negative pressure is released from the opening at the tip of the branch passage 45. Therefore, the EGR valve 22
The negative pressure supplied to the EGR valve 22 decreases, and the valve body 31 of the EGR valve 22 shuts off the EGR passage 21.

In this way, the EGR valve 22 repeats opening and closing, and during this time, the exhaust gas from the mallet according to the opening period is recirculated from the EGR passage 21 to the intake passage 11.

Moreover, the first valve is connected to the modulator valve 23. Second negative pressure introduction passage 2
4. When negative pressure is introduced from both of 25 (the opening degree of the throttle valve 12 is large ri), the second negative pressure introduction passage 2
5 into the negative pressure chamber 42, the diaphragm 41 completely closes the tip opening of the branch passage 45, so that the negative pressure in the first negative pressure introduction passage 24 always flows through the controlled negative pressure supply passage 27. The fuel is then supplied to the EGR valve 22.

As a result, the EGR valve 22 is held in an open state, and the amount of exhaust gas recirculated from the EGR passage 21 to the intake passage 11 is accordingly increased.

In other words, when negative pressure is introduced into the modulator valve 23 from the second negative pressure introduction passage 25 as the opening degree of the throttle valve 12 increases, the amount of exhaust gas recirculated increases, so an increase correction is applied. .

Next, regarding the relationship between the speed change pattern of the automatic speed change lll50 and the recirculation of exhaust gas, the control circuit 5 shown in FIG.
This will be explained with reference to a flowchart showing the operation of 3.54.

First, the control circuits 53 and 54 perform step S at the start of operation.
After initialization is performed in step I, in step S2 the selected shift pattern is read based on the shift pattern signal C from the shift pattern setting device 55, and in step S3 it is determined whether the pattern is a power pattern or an economy pattern. . When the selected pattern is a power pattern, step S4 is performed as shown in FIG. 3 (1).
) is called, and then in steps Ss, 86, and Sy, shift-up control, shift-down control, and lock-up control are performed according to this pattern.

That is, based on the signals A and B from the throttle opening sensor 51 and the turbine rotation sensor 52, the throttle opening and vehicle speed at that time are detected, and these values are combined with the power pattern map called in step S4 above. The gear position that should be set and the lock-up clutch ON while comparing the above.

OFF, and the first to fourth solenoids 57, to 57 of the hydraulic l control circuit 56 are activated to maintain the determined state.
4 and outputs E.

As a result, the automatic transmission 50 performs shift control and lock-up control according to the power pattern, and powerful driving mainly using the high rotation range of the engine 10 is performed.

On the other hand, when the economy pattern is selected by the shift pattern setting device 55, the economy pattern signal F is sent out, steps S3 to S8 are executed, and the economy pattern as shown in FIG. Matsubupu is called.

Next, in step S9, the gear position at which the automatic transmission 11150 is currently being driven is read via the shift control circuit 53, and if this is not a low gear position (1° 2nd gear), it is determined in step S++. Then, similarly to the above case, shift control and lock-up control according to the economy pattern are performed in steps Ss, Ss, and S7.

In this case, the economy pattern signal F is sent toward the three-way switching valve 26, but since the switch 40 is not activated, the switching valve 26 does not open the second negative pressure introduction passage 25 to the atmosphere. As a result, when the opening degree of the throttle valve 12 increases, an increase in the amount of exhaust gas recirculation is corrected.

Even in the economy pattern, where shift control is performed in a lower speed range than in the power pattern, as is clear from Figure 3 (IF), the vehicle is operated at fairly high speeds and high loads, so the exhaust gas is This is to prevent the generation of NOx by increasing the amount of exhaust gas recirculation.

On the other hand, if it is determined in step S+t that the transmission is operating in the 1st and 2nd gears, the switch 40 is actuated by the shift control circuit 53 in step So.
The economy pattern signal F is input to the direction switching valve 26,
After releasing the second negative pressure introduction passage 25 to the atmosphere, step S
s, Ss, and S7 are executed, and shift control and lock-up control are performed according to the set economy pattern.

In the control from step So, the second negative pressure introduction passage 25 is opened to the atmosphere, so the throttle valve 12
Even when the degree of opening is large, negative pressure is no longer introduced into the negative pressure chamber 42 of the modulator valve 23 shown in FIG. It becomes a state where
Along with this, the valve body 31 of the EGR valve 22 also acts as an EGR valve.
This results in a state in which the passage 21 is repeatedly opened and closed. As a result, even if the opening degree of the throttle valve 12 is large, the recirculation m of the exhaust gas to the intake passage 11 is corrected to a reduced amount in the same way as when the opening degree is small.

In this way, an economy pattern is selected, and
Since the amount of exhaust gas recirculated is reduced only when the vehicle is running in a low gear, it is possible to prevent deterioration in driving performance due to the amount of recirculated gas being too large relative to the condition of the engine. . In this case, in the low rotational speed range of the engine, the combustion temperature is low, so the amount of NOx generated is originally low.
Therefore, even if the amount of exhaust gas recirculation is reduced or the recirculation is stopped in this region, no adverse effects such as an increase in the amount of NOx emissions will occur.

In the above embodiment, the economy pattern is selected and the amount of exhaust gas recirculation is reduced in the case of a low gear. Control negative pressure supply passage 2 between
The EGR valve 22 may be completely closed and the recirculation of exhaust gas may be stopped by providing the EGR valve 22 on the EGR valve 7 or the like.

(Effects of the Invention) As described above in detail in the embodiments, the exhaust gas recirculation control device for an engine with an automatic transmission according to the present invention prevents deterioration in running performance due to recirculation of exhaust gas. Moreover, the generation of NOX can be suppressed as much as possible.

[Brief explanation of drawings]

Figure 1 is a block diagram showing the configuration of the device of the present invention, Figure 2 is a control system diagram, Figures 3 (I> and (II) are shift pattern diagrams showing examples of power patterns and economy patterns, respectively), and Figure 4. is an enlarged sectional view of the EGR valve in Fig. 2, Fig. 5 is an enlarged sectional view of the modulator valve, and Fig. 6 is a flowchart showing an example of control. 10...Engine 20... ... Exhaust gas recirculation device 26 ... Three-way switching valve 50 ... Automatic transmission patent applicant Mazda Corporation Representative Patent attorney - Kensuke Shiro
Patent Attorney Masatoshi Matsumoto Figure 1 Figure 3 (I) Economy rate ± (Km/h)

Claims (1)

[Claims] an exhaust gas recirculation device that recirculates part of the exhaust gas to the intake system; a speed change pattern setting device that arbitrarily sets a plurality of speed change patterns preset according to the vehicle speed; a transmission control means for upshifting or downshifting the gear of the automatic transmission; a shift pattern determining means for determining the shift pattern set by the shift pattern setting means; and a shift pattern determining means for determining the gear when the vehicle is running. gear determining means, and when the shift pattern determining means determines a shift pattern for upshifting in the lowest vehicle speed range, and the gear determining means determines a low gear, the exhaust gas recirculation means performs exhaust gas recirculation. 1. An exhaust gas recirculation control device for an engine with an automatic transmission, characterized in that it has an exhaust gas recirculation correction means for restricting a flow rate.