JPH05163937A - Air supplying device for engine - Google Patents

Abstract

PURPOSE:To achieve excellent rising-up responsiveness at the time of starting in a device for supplying air to an engine by using motor-driven pump. CONSTITUTION:Air which is press-fed from a motor-driven pump 33 is supplied immediate upstream of catalyst devices 7, 7 disposed at ends above independent exhaust passages 6a, 6b of an engine 3 through an air supply passage 35 when an engine operating condition is in a set high load region. An initial voltage, which is applied upon starting of the motor-driven pump 33, is changed to a value higher than that determined according to the load of the engine at the beginning when the engine operating condition is transferred to the high load region. Consequently, it is possible to improve a rising-up characteristic of the starting of the motor-driven pump 33, supply secondary air by an almost desired quantity to an exhaust system even at the beginning of the transfer to the high load region, and enhance exhaust emission purifying performance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an engine exhaust system.
The present invention relates to an engine air supply device such as a device for supplying secondary air, and more particularly to an improvement of the amount of air supplied to the engine during acceleration operation.

[0002]

2. Description of the Related Art Conventionally, for example, Japanese Utility Model Laid-Open No. 62-6791.
As disclosed in Japanese Unexamined Patent Publication No. 5 (1999), the acceleration state of the engine is detected, the amount of secondary air supplied around the catalyst device of the engine exhaust system is controlled according to the acceleration state, and the catalyst device is controlled by the secondary air. It is known that the exhaust gas purification effect is enhanced by promoting the oxidation of the unburned component of the fuel due to.

[0003]

By the way, in the air supply apparatus as described above, when the air is supplied by using the electric pump, the engine load is reduced as compared with the case where the air is supplied by the engine. At the same time, the electric pump can be driven only when air needs to be supplied, and fuel consumption can be improved.

However, in this case, when the electric pump is started by applying a voltage to it from the stopped state, such as when the engine operating state shifts to the secondary air supply region, the electric pump is started. Since it is not so early, the rise in the amount of secondary air does not rise sufficiently, and as a result, the amount of secondary air becomes less than the desired amount, and the unburned components of the fuel cannot be satisfactorily oxidized. In particular, since the required secondary air amount rapidly increases as the engine accelerates rapidly, the startup characteristics of the electric pump relatively deteriorate, and the exhaust gas purification performance tends to deteriorate.

The present invention has been made in view of the above circumstances, and an object thereof is to supply an electric pump to an engine using the electric pump as described above, regardless of the acceleration of the engine. It is intended to improve the rising characteristic and enhance the increase characteristic of the air supply amount at the time of starting the supply of air to the engine.

[0006]

In order to achieve the above object, the present invention has a configuration in which the applied voltage at the initial stage of starting the electric pump is changed in accordance with the degree of acceleration.

That is, the concrete solution means of the invention according to claim 1 is, as shown in FIG. 1, provided with an electric pump 33,
The target is an air supply device for an engine in which air is supplied to the engine 1 by the electric pump 33. Then, an acceleration degree detecting means 65 for detecting the acceleration degree of the engine 1, and an applied voltage changing means for changing the applied voltage at the initial stage of starting the electric pump 33 according to the acceleration degree detected by the acceleration degree detecting means 65. 66 is provided.

According to the second aspect of the present invention, its application is limited, and an electric pump is provided as a device for supplying secondary air to the exhaust system of the engine, and the electric pump is set when the load is higher than a set value. The target is an air supply device of an engine that applies a voltage to supply secondary air. Then, when the operating state of the engine enters a high load region equal to or more than the set value, the applied voltage at the start-up of the electric pump is set to the above-mentioned setting unit, which determines the operating state of the engine and the output of the determining unit. An applied voltage changing unit that changes the voltage higher than the voltage is provided.

Further, in the invention described in claim 3, the constituent features are added to the invention described in claim 2, an acceleration degree detecting means for detecting an acceleration degree of the engine is provided, and an applied voltage changing means is provided for the acceleration degree. According to the acceleration detected by the detecting means, the applied voltage at the initial stage of starting the electric pump is changed to be higher as the acceleration increases.

In addition, in the invention described in claim 4, the constituent features are added to the invention described in claim 1, claim 3 or claim 4, and an acceleration degree detecting means for detecting the acceleration degree of the engine is provided and applied. The voltage changing means is configured such that the period in which the applied voltage at the initial stage of starting the electric pump is changed to a high value in accordance with the acceleration detected by the acceleration detecting means is made longer as the acceleration increases.

Further, in the invention described in claim 5, the constituent features of the invention described in claim 2, claim 3 or claim 4 are added to determine the operating state of the engine, and the output of the determiner. Accordingly, the normal applied voltage changing means for changing the normal applied voltage after the initial startup of the electric pump to be higher as the engine operating state is under a higher load is provided.

According to the invention of claim 6, the acceleration degree detecting means of the invention of claim 1, claim 3 or claim 4 is specified and detected by the amount of change in the throttle valve opening of the engine. It consists of.

[0013]

With the above construction, in the invention of claim 1,
Since the applied voltage in the initial stage of starting the electric pump 33 is changed by the applied voltage changing means 66 according to the acceleration of the engine 1, the applied voltage in the initial stage can be changed to a higher value at the time of rapid acceleration when the amount of supplied air should be increased. Therefore, the higher the rapid acceleration, the higher the startup response of the electric pump, and the faster the amount of air supplied to the engine can be increased.

Further, according to the second aspect of the invention, when the engine operating state enters a high load region of a set value or more, the set voltage is applied to the electric pump, and the secondary air is supplied to the exhaust system of the engine. Supplied. In that case, since the applied voltage at the initial stage of starting the electric pump is changed to be higher than the set voltage, the rising response of the electric pump is increased, the secondary air amount is quickly increased to a predetermined value, and the unburned component of the fuel is increased. The exhaust gas purification performance is improved by responding favorably to the increase of. Moreover, since the electric pump is not connected to the engine, fuel consumption is improved.

At this time, although the amount of unburned components of the fuel increases with rapid acceleration, in the invention according to claim 3, the degree to which the applied voltage at the initial stage of starting is increased increases with rapid acceleration. Since the rising response of the electric pump increases in response to the increase in the amount of fuel components generated, the required secondary air amount can be quickly supplied in a short time regardless of the speed of acceleration, and exhaust purification performance can be improved. You can

According to the fourth aspect of the invention, since the applied voltage in the initial stage of starting is increased for a longer period of time during the rapid acceleration when the unburned component increases, the electric drive is performed in response to the increase in the unburned component. The startup response of the pump is enhanced, the amount of secondary air can be increased quickly, and the exhaust purification performance can be improved.

Further, in the fifth aspect of the invention, the higher the engine load is, the higher the normal applied voltage after the initial startup of the electric pump is set. The normal applied voltage thereafter smoothly shifts, and the connection between the initial supply of secondary air and the subsequent supply becomes smooth.

According to the sixth aspect of the present invention, the degree of acceleration of the engine is detected by the amount of change in the throttle valve opening of the engine, so that the degree of acceleration can be detected easily and accurately.

[0019]

As described above, according to the engine air supply apparatus of the first aspect, the start-up responsiveness at the initial stage of starting the electric pump is adjusted according to the acceleration of the engine. It is possible to improve the responsiveness of the air supply by increasing the degree of increase of the air supply amount at the start of the supply of the value as in the rapid acceleration.

Further, according to the second aspect of the present invention, when the engine operating state enters the high load region, the starting response of the electric pump is improved at the initial stage of startup, so that the secondary response to the engine exhaust system is improved. The amount of air supplied can be increased quickly in a short time.

Further, according to the third aspect of the present invention, since the applied voltage at the initial stage of starting the electric pump is changed to be higher as the acceleration is increased, the startup response at the time of starting the electric pump is improved as the acceleration is increased. The supply amount of secondary air to the engine exhaust system can be increased in response to an increase in the unburned component of the fuel, and the exhaust purification performance can be improved.

In addition, according to the invention described in claim 4, since the period for changing the applied voltage at the initial stage of starting the electric pump to be higher is lengthened as the acceleration is increased, the electric drive is performed similarly to the invention described in claim 3. The start-up response at the time of starting the pump improves as it accelerates, and the amount of secondary air supplied to the engine exhaust system can be increased in response to an increase in unburned components of the fuel. It is possible to improve.

According to the fifth aspect of the invention, the higher the engine operating state is, the higher the normal applied voltage of the electric pump is set. Therefore, when the engine load is high, the applied voltage is increased at the initial stage of starting the electric pump. By smoothly continuing the voltage to the normal applied voltage, it is possible to smoothly connect the secondary air supply response to the engine exhaust system and the subsequent control of the secondary air amount.

Further, according to the invention of claim 6, the degree of acceleration of the engine is detected by the opening degree of the throttle valve of the engine, so that the degree of acceleration can be detected easily and accurately.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIGS.

In FIG. 2, reference numeral 1 denotes a V-type engine, and combustion chambers 4 having variable volumes are formed in the left and right banks 1a and 1b by pistons 3 which are fitted in cylinders 2 which are inclined at a predetermined angle. Has been done. Each of the combustion chambers 4 is communicated with the atmosphere through independent intake passages 5a, 5b and a single collective intake passage 5c obtained by merging both of these passages at their upstream ends, and an independent exhaust passage 6a. , 6b and a collective exhaust passage 6c that collects the exhaust passages and is exposed to the atmosphere. An air cleaner 10 is arranged at the upstream end of the collective intake passage 5c, a throttle valve 12 for adjusting the amount of intake air is arranged midway, and a negative pressure chamber 11 is arranged at the downstream end. Further, fuel injection valves 18 for injecting and supplying fuel are arranged at the downstream ends of the independent intake passages 5a and 5b, respectively.

Further, the catalyst devices 7, 7 are directly connected to the independent exhaust passages 6a, 6b at a portion directly below the exhaust port, and the collective exhaust passage 6c is arranged in order from the upstream to the catalyst device 20.
And an exhaust silencer 21 are provided.

Further, 25 is a fuel tank, and in the fuel tank 25, a fuel pipe 3 in which an in-tank filter 26, a fuel pump 27, and a fuel filter 28 are arranged.
The upstream end of 0 is located. A downstream side of the fuel filter 28 of the fuel pipe 30 is communicatively connected to the fuel injection valve 18, and a pressure regulator 31 and an electromagnetic valve 32 for controlling the pressure regulator 31 are disposed further downstream thereof, and the surplus fuel thereof is disposed. Is returned to the fuel tank 25 through the return pipe 31a.

In addition, 33 is an electric pump for supplying air. The air suction side of the electric pump 33 communicates with the air intake passage 5c immediately downstream of the air cleaner 10 through the suction passage 34, and the air discharge side. Is branched into two, one is further branched into two via the air supply passage 35, and then the independent exhaust passage 6 is formed.
The catalyst devices 7 and 7 at the upstream ends of a and 6b are opened immediately upstream. The other air supply passage 36 is the catalyst device 2 of the collective exhaust passage 6c.
0 Open inside.

On-off valves 37 and 38 for opening and closing the passages 35 and 36 are provided in the middle of the two air supply passages 35 and 36.
Also, a check valve 40 is provided, and the on-off valves 37 and 38 are provided.
Are connected to solenoid valves SOL1 and SOL2. When the solenoid valves SOL1 and SOL2 are turned on, the negative pressures of the negative pressure passages 39a and 39b communicating with the negative pressure chamber 11 are introduced into the corresponding on-off valves 37 and 38, respectively. The opening / closing valves 37 and 38 are opened.

Further, 41 is a canister, which collects the evaporated fuel in the fuel tank 25 by the canister 41, and the collected fuel passes through the purge control valve 42 and the purge passage 43 and the throttle valve of the collective intake passage 5c. 12 is supplied to the downstream side. In the figure, 44 is a resonator and 45 is an EGR control valve.

In addition, 51 is an air flow sensor for detecting the amount of intake air, 52 is an intake air temperature sensor arranged immediately downstream of the air cleaner 10, 53 is an opening sensor for detecting the opening of the throttle valve 12, 54, 55. Left and right banks 1
Vibration sensors arranged in a and 1b to detect engine vibration, 56 is a cooling water temperature sensor, 57 is a cold start water temperature switch, and 58 and 58 are independent exhaust passages 5.
O ₂ sensors arranged at a and 5b for detecting the air-fuel ratio of the air-fuel mixture, and 59 are crank angle sensors for detecting the engine speed from the crank angle of the engine 1.

Then, the above-mentioned sensors and switches 51 to 51
The signal of 59 is supplied to the controller 6 having a CPU or the like inside.
Input to 1. The controller 61 controls the electric pump 33 and the solenoid valve SOL1 to open / close the open / close valve 37 to control the secondary air to the secondary exhaust air of the exhaust system of the engine 1 and the catalyst device 7 at the upstream end of the independent exhaust passages 6a, 6b. , 7 is supplied.

Next, the control of the electric pump 33 and the opening / closing valve 37 by the controller 61 will be described based on the control flow of FIG. In the figure, after starting, in step S1, the intake air amount Qa from the air flow sensor 51, the engine speed Ne from the crank angle sensor 59,
After reading the throttle valve opening TVO from the opening sensor 53 and the intake air amount Qa and the engine speed Ne read in step S2, the intake charge amount Ce per process of the engine 1 is calculated, Based on the intake air charge amount Ce and the engine speed Ne, the engine operating state is set to a high load region of a set value or more as shown in FIG.
It is determined whether or not it is in the next air supply area.

If it is not in the secondary air supply region, the value of the high voltage control flag F1 of the applied voltage of the electric pump 33 is determined in step S3, and initially F1 ≠ 1 (non-high voltage control is being performed). ), The difference between the previous value TVOn-1 and the current value TVOn of the throttle valve opening TVO, that is, the changing speed a of the throttle valve opening is equal to or greater than a set value α corresponding to acceleration of a predetermined value or more in step S4. If it is determined that the acceleration is greater than a predetermined value of a> α, the initial voltage Va at the initial stage of starting the electric pump 33 and the timer initial value Ta for holding the value are throttled from the table shown in FIG. It is read based on the changing speed a of the valve opening. Here, in the table of FIG. 5, the larger the changing speed a of the throttle valve opening, the higher the initial voltage Va and the longer the timer initial value Ta is set in advance.

Then, after the high voltage control flag F1 is set to F1 = 1 in step S6, steps S7 and S8 are performed.
Then, the timer initial value Ta is set in the timer and the initial applied voltage Va is set, but since it does not move to the secondary air supply region yet, the solenoid valve 37 is turned off in step S9.
The on-off valve 37 is controlled to be closed.

Then, if the engine operating state is not yet shifted to the secondary air supply region of FIG. 4 in step S2 next time, the high voltage control flag F1 = 1 in step S3, so the timer is used in step S10. Determine the value of T,
When ≠ 0, the timer value T is subtracted, and step S11
The applied voltage V is maintained at the initial voltage Va, but T = 0.
Then, in step S13, the applied voltage V is changed to the minute voltage V
b is subtracted to slightly lower the applied voltage V next time, and when V = 0 is reached in step S14, the high voltage control flag F1 is returned to F1 = 0 in step S15.

On the other hand, when the engine operating state shifts to the secondary air supply region in step S2, the intake air amount Qa and the engine speed Ne are read in step S16, and the engine load based on these Qa and Ne is read. Accordingly, the voltage V1 after the initial start-up to be applied to the electric pump 33 is read from the table stored in advance. In this table, the normal applied voltage V1 is set to a large value as the engine load increases and the load increases. Then, in step S17
In step S18, the value of the high voltage control flag F1 is determined, and in the case of high voltage control of F1 = 1, the value of the timer value T is determined. If T ≠ 0, the voltage is applied in step S19. The voltage V is held at the high voltage value Va, the timer value T is subtracted in step S20, and the solenoid valve 37 is turned on in step S21.
The on-off valve 37 is controlled to open, and the secondary air is supplied from the electric pump 33 to the upstream of the catalyst devices 7, 7 through the air supply passage 35.

Then, in step S18, the timer value T = 0
Then, in step S22, the current applied voltage V is compared with the applied voltage V1 according to the engine load. If V> V1, the voltage value obtained by subtracting the minute voltage Vb from the current applied voltage V in step S23. Is set as the applied voltage V for the next time, the high voltage control flag F1 = 0 is returned to in step S24,
In step S21, the supply of the secondary air is continued and the applied voltage V
Is equal to the applied voltage V1 according to the engine load (V = V
In step S25, the current applied voltage V is maintained at the normal applied voltage V1 (V = V1) and the supply of secondary air is continued.

On the other hand, if F1 ≠ 1 in step S17,
In other words, the acceleration a ≦ α and 2
When shifting to the next air supply region, the value of the high-voltage control flag F2 during this slow acceleration is determined in step S26, and in the case of high-voltage control of F2 = 1, step S27.
Then, the current value of the applied voltage V is compared with the normal applied voltage value V1 according to the engine load. If V> V1, step S
At 28, the applied voltage V is set low by a minute value Vb (V-V
b) Then, in step S21, the solenoid valve SOL1 is turned on,
The on-off valve 37 is opened, and the air is supplied from the electric pump 33 directly upstream of the catalyst devices 7, 7. After that, when the applied voltage V becomes equal to V = V1 in step S27, step S29
After setting the flag F2 = 0 in step S30, the applied voltage V = V1 is maintained in step S30 and the process returns to step S21 to continue the supply of secondary air.

Therefore, in the control flow of FIG.
In step S4, the acceleration degree detection means 65 is configured to detect the acceleration degree of the engine 1 with the variation amount a (= TVOn-TVOn-1) of the opening degree of the throttle valve 12. Further, in step S5 of the control flow, when the acceleration degree a detected by the acceleration degree detecting means 65 exceeds the set value α (a> α) and acceleration is not less than a predetermined value, the electric pump 33 is in accordance with the acceleration degree a. The applied voltage changing means 66 is configured so as to change the applied voltage Va at the initial stage of start-up and set the initial applied voltage Va higher as the acceleration degree a increases as shown in FIG. Further, the step S1 constitutes the discriminating means 67 for discriminating the operating state of the engine 1 on the basis of the intake air amount Qa and the engine speed Ne, and by the steps S2, S5 and S19,
When the engine operating state enters the secondary air supply region of FIG. 4 in response to the output of the discrimination means 67, the initial applied voltage V of the electric pump 33 is read and set as the high voltage value Va from the table of FIG. A value higher than the normal applied voltage V1 (Va> V1) after the initial startup, which is determined according to the engine load.
In addition, the high voltage value Va read from the table of FIG. 5 is set higher as the acceleration rate a is larger, and the period T for holding this high voltage value Va is set to the acceleration rate a.
The applied voltage changing means 68 is configured to be set longer as the value is larger.

Further, in step S16 of the control flow, the higher the engine load determined by the intake air amount Qa and the engine speed Ne, the higher the normal applied voltage V1 applied to the electric pump 33 after the initial startup is set. The normal applied voltage changing means 69 is configured to do so.

Therefore, in the above embodiment, when the engine operating state shifts to the secondary air supply region shown in FIG. 4, the solenoid valve SOL1 is ON-controlled to open and close the opening / closing valve 37 and the electric pump. Since the voltage V is applied to 33, the electric pump 33 starts to start, and the air from the electric pump 33 passes through the air supply passage 35 and is directly upstream of the catalyst device 7, 7 in the independent exhaust passages 6a, 6b. Is supplied to. As a result, the unburned components of the fuel flowing down into the independent exhaust passages 6a and 6b are oxidized by the supply of the secondary air, and the exhaust purification performance is improved.

At this time, when the acceleration a of the engine 1 exceeds a preset value α and is accelerated for a predetermined amount or more, the voltage V applied to the electric pump 33 is changed from the stage before the operating state enters the secondary air supply region to the value shown in FIG. As shown in 6, the normal applied voltage V after the initial stage of startup, which is determined according to the engine load from the time when the acceleration is detected.
Since the initial voltage Va is set higher than 1, the startup characteristic of the electric pump 33 is improved. As a result, when the engine operating state actually shifts to the secondary air supply region, immediately after that, the secondary air is rapidly supplied to the catalyst devices 7, 7 just upstream of the catalyst device 7, so that no fuel is left. Most of the fuel components can be oxidized.

Moreover, at the time of sudden acceleration, although the unburned component of the fuel suddenly increases, the initial voltage Va is set higher and the holding time T of the initial voltage Va is maintained for a long time. Since the start-up of 33 is further quickened and the increase in the secondary air supply amount of the electric pump 33 corresponds to the increase in the unburned component, the exhaust gas purification performance is ensured excellently even during this sudden acceleration.

Further, when the engine 1 has a high load, the amount of unburned components generated also increases, but since the normal applied voltage value V1 is changed to a high value and the supply amount of required secondary air also increases,
Good exhaust purification performance is secured. As described above, even when the initial applied voltage Va of the electric pump 33 is changed to a higher value than the normal applied voltage value V1 according to the engine load when the electric pump 33 is started, the normal applied voltage value V1 is changed to a high value at the high load. The normal applied voltage V from the initial voltage Va
The transition to 1 becomes smooth, and therefore the connection between the beginning of the supply of secondary air and the subsequent control of the amount of secondary air can be made smooth.

Further, since the degree of acceleration of the engine 1 is detected by changing the opening of the throttle valve 12, the detection can be performed easily and accurately.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an invention according to claim 1.

FIG. 2 is a diagram showing an overall configuration.

FIG. 3 is a flowchart showing control of a supply amount of secondary air to an engine exhaust system.

FIG. 4 is an explanatory diagram of a secondary air supply region.

FIG. 5 is a diagram showing a table of applied voltage at the initial stage of starting the electric pump and its maintenance time with respect to the acceleration of the engine.

FIG. 6 is an operation explanatory view.

[Explanation of symbols]

 1 engine 6a, 6b independent exhaust passage 7 catalyst device 33 electric pump 35 air supply passage SOL1 solenoid valve 61 controller 65 acceleration detection means 66, 68 applied voltage changing means 67 discriminating means 69 normal applied voltage changing means

Front page continuation (72) Hideki Yamada Inventor Hideki Yamada 3-1, Shinchi, Fuchu-cho, Aki-gun, Hiroshima Mazda Motor Corporation

Claims (6)

[Claims] 1. An air supply apparatus for an engine, comprising an electric pump, wherein air is supplied to the engine by the electric pump, the acceleration degree detecting means detecting an acceleration degree of the engine, and the acceleration degree detecting means. And an applied voltage changing means for changing the applied voltage at the initial stage of starting the electric pump according to the acceleration detected by the engine air supply device. 2. An air supply device for an engine, comprising an electric pump, wherein a set voltage is applied to the electric pump to supply secondary air to an exhaust system of the engine at a high load of a set value or more, When the engine operating state enters a high load region equal to or higher than the set value, the applied voltage in the initial stage of starting the electric pump is set to be higher than the set voltage when the engine operating state enters a high load region above the set value. An air supply apparatus for an engine, further comprising: an applied voltage changing unit that changes the height to a higher value. 3. An acceleration degree detecting means for detecting an acceleration degree of the engine is provided, and the applied voltage changing means applies the electric power at the initial stage of starting the electric pump as the acceleration increases according to the acceleration degree detected by the acceleration degree detecting means. The air supply device for an engine according to claim 2, wherein the voltage is changed to a high value. 4. An acceleration degree detecting means for detecting an acceleration degree of the engine is provided, and the applied voltage changing means changes the applied voltage at an initial stage of starting the electric pump to be high according to the acceleration degree detected by the acceleration degree detecting means. The air supply device for an engine according to claim 2 or 3, wherein the period during which the engine is operated is lengthened as the acceleration is accelerated. 5. A discriminating means for discriminating an operating state of the engine, and a normal applied voltage for receiving the output of the discriminating means and changing the normal applied voltage after the initial start of the electric pump to be higher as the engine operating state is under a higher load. The air supply device for an engine according to claim 2, 3, or 4, further comprising: a changing unit. 6. The acceleration degree detecting means detects the amount of change of the throttle valve opening of the engine.
The air supply device for the engine according to claim 3 or 4.