JP3351551B2 - Engine control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for an engine in which fuel supply to the engine is stopped in a predetermined deceleration region.

[0002]

2. Description of the Related Art In general, when an automobile is decelerated, it is not always necessary to generate torque by an engine, but it is sometimes preferable not to generate torque because an effective engine brake can be obtained. Therefore, a fuel injection engine in which fuel is supplied to the combustion chamber by using a fuel injection valve is usually provided with a fuel supply stopping means for stopping fuel supply to the engine in a predetermined deceleration region.

In such a fuel supply stopping means, if the fuel supply to all cylinders is stopped in a predetermined deceleration region, there is an advantage that the fuel efficiency can be maximized and an effective engine brake can be obtained. . However,
In this case, when the fuel supply is stopped, the engine torque becomes a large negative value, so that there is a problem that a strong torque shock occurs when the fuel supply is stopped during deceleration.

Therefore, for example, as shown in FIG. 10, a normal region for supplying fuel to all cylinders (a fuel supply region for all cylinders),
Between a predetermined deceleration region (all-cylinder fuel cut region) in which fuel supply to all cylinders is stopped, a buffer-like region (partial-cylinder fuel cut region) in which fuel supply to only some cylinders is stopped. There has been proposed a fuel supply stopping means for reducing the torque shock by gradually decreasing the engine torque when stopping the fuel supply during deceleration (see, for example, Japanese Patent Application Laid-Open No. 58-101234). ). In addition, when the operating state of the engine enters the idle region during the deceleration, the fuel supply is restarted so as not to cause engine stall.

[0005]

FIG. 11 shows an actual example of the engine torque in each region when the partial cylinder fuel cut region is provided between the normal region and the all cylinder fuel cut region. . As is clear from FIG. 11, even when the partial cylinder fuel cut region is provided, the engine torque in the full cylinder fuel cut region has a strong negative value, so that the partial cylinder fuel cut region and the full cylinder fuel cut region However, there is a problem that a considerably large torque difference is generated between the two, and thus the torque shock generated at the time of deceleration cannot be sufficiently suppressed.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems. In an engine in which fuel supply to all cylinders is stopped in a predetermined deceleration region, fuel supply is stopped. It is an object of the present invention to provide an engine control device capable of effectively preventing the occurrence of a torque shock at the time.

[0007]

In order to achieve the above object, as shown in FIG. 1, in the first invention, the supply of fuel to each cylinder is arbitrarily stopped according to the operating state of the engine CE. A fuel supply stopping means A capable of stopping fuel supply to each of the cylinders in a predetermined deceleration region according to the operating state of the engine. In the deceleration region in which the fuel supply to all the cylinders is stopped by the fuel supply stopping device A, the intake late closing is performed in the high load side partial region. On the other hand, there is provided an engine control device characterized in that an intake late closing control means C for controlling the intake late closing means B so that the intake late closing is not performed in the partial region on the low load side is provided. Do

According to a second aspect of the present invention, in the engine control device according to the first aspect, the fuel supply stopping means A comprises:
In a predetermined deceleration region adjacent to the deceleration region where the fuel supply to all the cylinders is stopped from the high load side, the fuel supply to some of the cylinders is stopped. The region in which fuel supply to all cylinders is stopped is set between the region in which fuel supply to some of the cylinders is stopped and the region in which fuel supply to all cylinders is stopped without performing intake late closing. An intake device for an engine is provided.

Further, a third aspect of the present invention relates to the engine control device according to the first or second aspect, wherein the engine C
E is a rotary piston engine, and the intake late closing means B is a pumping loss reducing means provided with a communication passage for communicating the working chambers in the intake process of each cylinder and an on-off valve for opening and closing the communication passage. An engine control device is provided.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below. <First Embodiment> As shown in FIG. 2, a two-cylinder rotary piston engine RE is provided with a first cylinder P and a second cylinder S. In the first cylinder P, when the intake port 3p opening to the inner surface of the side housing 2p forming the side wall of the casing 1p is opened, the independent intake passage 4p
The mixture is sucked into the working chambers 5p, 6p, and 7p from below, and the mixture is compressed by the rotor 8p and ignited and burned by the two spark plugs 9p, and the inner periphery of the rotor housing 10p forming the peripheral wall of the casing 1p. When the exhaust port 11p opening to the surface communicates with the working chambers 5p, 6p, 7p, a process of discharging combustion gas to an exhaust passage (not shown) is repeated. Along with this, the rotor 8p makes a planetary rotation around the eccentric shaft 12 while sliding its top portion against the inner peripheral surface of the trochoid of the rotor housing 10p, and the eccentric shaft 12 rotates with this planetary rotation, The rotational force of the eccentric shaft 12 is taken out as the output of the engine RE. A fuel injection valve 13p for injecting fuel into the air is provided in the independent intake passage 4p near the intake port 3p.
Is provided. Since the second cylinder S has basically the same configuration as the first cylinder P, detailed description thereof will be omitted, but the second cylinder S corresponding to each member 1p to 13p of the first cylinder P will be described.
Each member of the cylinder S is assigned the same number as the first cylinder P, and the subscript is s.

A common intake passage 16 is provided for supplying air for fuel combustion to the engine RE. The common intake passage 16 has a throttle valve 17 which is opened according to the depression amount of an accelerator pedal (not shown). Is provided. A throttle sensor 18 for detecting the opening of the throttle valve 17 (throttle opening) is provided. The downstream end of the common intake passage 16 is connected to a surge tank 19 (volume portion) for stabilizing the flow of intake air, and the surge tank 19 is provided with an independent of the first and second cylinders P and S. The upstream ends of the intake passages 4p and 4s are connected. The surge tank 19 is provided with a boost sensor 20 for detecting an intake boost and an intake temperature sensor 21 for detecting a temperature of intake air.

The fuel injection valves 13p and 13s are controlled by a control unit 26, which will be described later. In a normal operation range, the fuel injection valves 13p and 13s inject fuel that can maintain a predetermined air-fuel ratio in accordance with the intake air amount. ing. However, at the time of predetermined deceleration, fuel injection from the fuel injection valves 13p and 13s of one cylinder or both cylinders is stopped. Specifically, fuel is supplied to both cylinders P and S in a normal region or an idle region indicated by region D in FIG. 5, and is supplied to both cylinders P and S in a relatively strong deceleration region indicated by regions A and B. The fuel supply is stopped (all-cylinder fuel cut), and the fuel supply to one cylinder P (S) is stopped in region C, which is a relatively weak deceleration region set between region D and region B. (Partial cylinder fuel cut).

In order to reduce pumping loss in a predetermined operating region, the air in the working chambers 5p to 7p (5s to 7s) of one cylinder P (S) at the beginning of the compression stroke is supplied to the engine RE. The working chamber 5s of the other cylinder S (P) in the intake stroke
手段 7s (5p〜7s) is provided with pumping loss reducing means (slow intake closing means).

The pumping loss reducing means is, specifically, a communication port 23p opened on the inner peripheral surface of the side housing 2p of the first cylinder P and a communication port opened on the inner peripheral surface of the side housing 2s of the second cylinder S. It comprises a communication passage 24 that communicates with the port 23s, and an on-off valve 25 that opens and closes the communication passage 24. And each communication port 23p, 23s
Each of the intake ports 3p, 3s is arranged on the leading side by a predetermined eccentric axis angle (for example, 30 to 50 °) with respect to the corresponding intake port 3p, 3s.
The valve is closed with a delay of the above-mentioned eccentric axis angle from p and 3s (slow intake closing). For this reason, the working chambers 5p to 7p (5s to 7s) communicating with one of the communication ports 23p (23s).
Is in the early stage of the compression stroke, the other communication port 23
The relationship that the working chambers 5s to 7s (5p to 7p) communicating with s (23p) are in the intake stroke is always established. Therefore, when the on-off valve 25 is opened, the operation in the early stage of the compression stroke is performed. The air in the chambers 5p to 7p (5s to 7s) is released to the working chambers 5s to 7s (5p to 7p) of the other cylinder in the intake stroke, and the pumping loss is reduced.

More specifically, as shown in FIG. 3A, when the working chamber 5p of the first cylinder P is in the early stage of the compression stroke,
The working chamber 5s of the second cylinder S is in the intake stroke. At this time, the air in the working chamber 5p is released to the working chamber 5s through the communication passage 24 as shown by the arrow X, and the working chamber 5p is in this communication state. During some time, the air is not compressed and therefore no compression resistance occurs. On the other hand, on the working chamber 5s side, the working chamber 5p
, The intake negative pressure is weakened and the suction resistance is reduced. Thus, the resistance of the eccentric shaft 12 is reduced, and the pumping loss is reduced. After this, FIG. 3 (b),
As shown in (c), after the communication port 23p is closed, the air in the working chamber 5p is gradually compressed as the rotor 8p rotates. Similarly, when the working chamber 5s of the second cylinder S enters the compression stroke, the air in the working chamber 5s is released to the first cylinder P side as indicated by an arrow Y in FIG.

Here, the on-off valve 25 is controlled by the control unit 26 and is opened in a predetermined operation range, so that the fuel efficiency is enhanced by reducing the pumping loss. Further, the on-off valve 25 is generally opened for the purpose of improving the fuel efficiency as described above. In addition, in the all-cylinder fuel cut-off region indicated by the region B in FIG. It is opened to prevent

The control unit 26 is a comprehensive control means of the engine RE including the "fuel supply stopping means" and the "slow intake closing control means" described in the claims, and is detected by the throttle sensor 18. Throttle opening TVO, intake boost detected by boost sensor 20, intake air temperature detected by intake air temperature sensor 21, engine speed detected by rotation speed sensor 27, engine water temperature detected by water temperature sensor 28, A starter start signal or the like output from the starter switch 29 is used as control information to control the fuel supply to the fuel injectors 13p and 13s or to stop the fuel supply, and to open / close the valve 2.
Various controls such as the opening / closing control for the fuel cell 5 are performed, but only the fuel supply stop control during deceleration according to the present application and the opening / closing control of the opening / closing valve 25 related thereto will be described below with reference to the flowchart shown in FIG. explain.

When the control is started, in step # 1, various data such as the throttle opening and the engine speed are read. Next, in steps # 2 to # 5, it is determined which of the areas A to D or the idle area in FIG. 5 the operating state of the engine RE is in. Specifically, if it is determined that the engine speed is less than R1 (NO in step # 2), it means that the operating state of engine RE is in the idle region, and therefore, step #
At 8, normal fuel control is performed. That is, fuel is supplied to both cylinders P and S. Subsequently, step # 11
Then, the on-off valve 25 is closed to stabilize the idling operation, and thereafter, the process returns to step # 1.

If it is determined that the throttle opening exceeds the SD3 line (NO in step # 3), or if it is determined that the throttle opening exceeds TVO1,
(NO in step # 4), which means that the operating state is in the region D, so that normal fuel control is performed in step # 8. Subsequently, the on-off valve 25 is closed in step # 11 to secure the engine output. It should be noted that the on-off valve 25 may be opened by other control not mentioned in the present embodiment in order to improve fuel efficiency. Thereafter, the process returns to step # 1.

When the engine speed is equal to or higher than R1 (YES in step # 1), the throttle opening is TVO1 and S
When it is determined that the distance is equal to or less than the D3 line and exceeds the SD2 line (YES in steps # 3 and # 4,
5 is NO), which means that the operating state is in the region C, so that a partial cylinder fuel cut is performed in step # 7. Then, in order to improve the combustion stability, step # 1
In step 1, the on-off valve 25 is closed, and thereafter, the process returns to step # 1.

When the engine speed is equal to or higher than R1 (YES in step # 1) and it is determined that the throttle opening is equal to or lower than TVO and equal to or lower than the SD2 line (YES in steps # 3, 4, and 5). ), Since the operation state is in the region B or the region A, all-cylinder fuel cut is performed in step # 6. Subsequently, in step # 9,
It is determined whether or not the throttle opening is equal to or more than the SD1 line, and when it is determined that the throttle opening is equal to or more than the SD1 line (YE
S), that is, when the logical condition as shown in FIG. 6 is established in each switch, the operating state is in the region B. In this case, the pumping loss is reduced to reduce the negative torque of the engine RE. Step # 1 to mitigate
At 0, the on-off valve 25 is opened. Each switch is set with a hysteresis as shown in FIG. 7 so that a problem such as hunting does not occur. Thereafter, the process returns to step # 1.

On the other hand, if it is determined in step # 9 that the throttle opening is less than the SD1 line (NO), the on-off valve 25 is closed in step # 11 to obtain an effective engine brake. Thereafter, the process returns to step # 1.

FIG. 8 shows an example of the engine torque generated in the regions A to D when such control is performed. As is clear from FIG. 8, the engine torque gradually decreases from the region A to the region D, and the torque step between the adjacent regions decreases. Therefore, torque shock does not occur even when the fuel is cut during deceleration. The torque shock is effectively prevented even when the foot is not separated from the accelerator pedal, that is, at the time of so-called deceleration.

FIG. 9 shows changes over time in the throttle opening (H ₁ ) and the engine torque (H ₂ ) when the fuel cut is performed during deceleration. As is apparent from FIG. 9, since the engine torque is gradually reduced, no torque shock occurs. In the conventional fuel stop control during deceleration, there is a portion where the engine torque sharply decreases as shown by a broken line H ₂ ′, and a torque shock occurs here. As described above, according to the first embodiment, it is possible to effectively prevent the occurrence of the torque shock when performing the fuel cut during the deceleration.

<Second Embodiment> Hereinafter, a second embodiment will be described in detail. In the second embodiment, the engine is a reciprocating engine and the intake late closing means is a variable valve timing mechanism.
Since the first embodiment is basically the same as the first embodiment, the description of the same points as those of the first embodiment will be omitted. As shown in FIG. 12, in the reciprocating engine CE, when the intake valve 31 is opened, the independent intake passage 3
An air-fuel mixture is sucked into the combustion chamber 34 from the combustion chamber 3, and the air-fuel mixture is compressed by a piston 35 and then ignited and burned by a spark plug 36. The process of discharging to the exhaust passage 39 through the exhaust passage 39 is repeated. Note that a catalyst converter 45 is provided in the exhaust passage 39,
A fuel injection valve 66 is provided in the independent intake passage 33 near the intake port 32. By repeating this process, the piston 35 reciprocates in the cylinder axis direction, and this reciprocation is converted into rotational motion by the connecting rod 41, the crankpin 42, and the crank arm 43, and transmitted to the crankshaft 44. It has become.

The intake valve 31 is opened and closed at a predetermined timing in synchronization with a crankshaft 44 by a plurality of intake valve cams 52 attached to an intake side camshaft 51. Similarly, the exhaust valve 37 is opened and closed by a plurality of exhaust valve cams 54 attached to the exhaust-side camshaft 53. A variable valve timing mechanism 55 is provided for the intake camshaft 51. The variable valve timing mechanism 55 retards the rotation phase of the intake camshaft 51 in accordance with a signal applied from the control unit 60. Is available. Therefore, the opening / closing timing of the intake valve 31 is delayed according to the operating state of the engine CE,
As in the case of the first embodiment, the intake late closing can be performed. That is, in the second embodiment, the variable valve timing mechanism 55 is an intake late closing means.

A common intake passage 61 is provided for supplying air to the engine CE.
In order from the upstream side in the air flow direction, the air cleaner 62
, An air flow meter 63 and a throttle valve 64. The downstream end of the common intake passage 61 is connected to the surge tank 65, and the upstream end of the independent intake passage 33 is connected to the surge tank 65. A bypass intake passage 67 that bypasses the throttle valve 64 is provided, and an ISC valve 68 is provided in the bypass intake passage 67.

The control unit 60 is a comprehensive control means including the "fuel supply stopping means" and the "slow intake closing control means" described in the claims, and is substantially the same as that of the first embodiment. The same fuel supply stop control and intake late closing control are performed in a similar manner to effectively prevent the occurrence of torque shock when fuel cut is performed at the time of predetermined deceleration.

As shown in FIG. 13, the variable valve timing mechanism 55 is a hydraulic type variable valve timing mechanism, and the rotation of the timing gear 85 driven by the crankshaft 44 (see FIG. The power is transmitted to the camshaft 51 via the piston 84, the piston 83, and the hub 82. The journal 87 of the camshaft 51 is rotatably supported by a bearing 99 formed on the cylinder head 98. The inter-cam gear 8 is attached to the cam shaft 51 using a lock nut 89, and the space between the cylinder head 98 and the spacer 86 is sealed by a seal member 100.

The piston 83 incorporated between the sleeve 84 and the hub 82 has a cylindrical structure divided into two parts in the front and rear directions, and the two divided members are connected to each other by a pin 90. The inner peripheral surface and the outer peripheral surface of the piston 83 have helical splines 91,
92 are formed. Here, the inner spline 91
Engages with a helical spline 93 formed on the outer peripheral surface of the hub 82, while the outer spline 92 engages with a helical spline 94 formed on the inner peripheral surface of the sleeve 84. The piston 83 is always urged forward by a spring 95.

The hub 82 is fixed to the camshaft 51 via a locking member 96 by a fixing bolt 97.
Then, although not shown in detail, when hydraulic pressure is applied to the front surface of the piston 83 through an oil passage formed in the fixing bolt 97, the piston 83 is retracted against the urging force of the spring 95, At this time, the operation of the splines 91, 92, 93, 94 causes the hub 82 and the sleeve 84 to rotate relatively in opposite directions. Therefore, the rotational phase between the camshaft 51 that rotates integrally with the hub 82 and the timing gear 85 that rotates integrally with the sleeve 84 shifts, and the valve timing changes.
When the hydraulic pressure is released, the piston 8
3 is advanced by the spring 95, and the valve timing is returned to the original.

As described above, also in the second embodiment, as in the first embodiment, the torque shock when the fuel is cut during deceleration is effectively prevented.

[0033]

According to the first aspect of the invention, when fuel cut to the engine is performed at the time of deceleration, first, all-cylinder fuel cut is performed in the intake late closing state with small pumping loss. All-cylinder fuel cut is performed in a state where the pumping loss is large, with the intake late closing being canceled. Therefore, the engine torque changes stepwise during the deceleration fuel cut, and the occurrence of torque shock is prevented.

According to the second aspect, basically the same operation and effect as those of the first aspect can be obtained. Further, when a fuel cut is performed during deceleration, first, a partial cylinder fuel cut in which the output torque of the engine is positive is performed, and then a full cylinder fuel cut is performed in the intake late closing state with a small pumping loss. Since all cylinder fuel cut is performed in a state where the pumping loss is large when the intake late closing is finally released, the change in the engine torque at the time of deceleration fuel cut becomes more gentle, and the occurrence of torque shock is more reliably prevented. .

According to the third aspect, basically, the same operation and effect as those of the first or second aspect can be obtained. further,
Since the engine is a rotary piston engine and the intake late closing means is composed of a communication passage and an on-off valve, the intake late closing means and the intake late closing control means have a very simple structure.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of the present invention.

FIG. 2 is a system configuration diagram of a rotary piston engine including a control device according to the present invention (first embodiment).

FIG. 3 is a diagram showing a state of communication between cylinders of the rotary piston engine shown in FIG. 2;

FIG. 4 is a flowchart illustrating a control method of fuel supply stop control.

FIG. 5 is a diagram showing a fuel cut region with respect to a throttle opening and an engine speed;

FIG. 6 is a diagram illustrating a logical configuration of each switch when the on-off valve is opened.

FIG. 7 is a diagram showing hysteresis characteristics of each switch.

FIG. 8 is a diagram comparing engine torques in respective operation regions.

FIG. 9 is a diagram showing changes over time in throttle opening and engine torque during deceleration fuel cut.

FIG. 10 is a diagram showing a fuel cut region in a conventional fuel supply stop control device with respect to a throttle opening and an engine speed.

FIG. 11 is a diagram comparing engine torques in respective operation regions in a conventional fuel supply stop control device.

FIG. 12 is a system configuration diagram of a reciprocating engine including a control device according to the present invention (second embodiment).

13 is an explanatory side sectional view of the variable valve timing mechanism of the engine shown in FIG. 12;

[Explanation of symbols]

 RE: rotary piston engine CE: reciprocating engine P, S: first and second cylinders 5p, 6p, 7p: working chamber 5s, 6s, 7s: working chamber 13p, 13s: fuel injection valve 24: communication passage 25: open / close valve 26 control unit 55 variable valve timing mechanism 60 control unit 66 fuel injection valve

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁷ Identification code FI F02D 17/02 F02D 17/02 R 41/12 330 41/12 330J 43/00 301 43/00 301H 301Z (72) Inventor Inoue Shin No.3-1 Shinchi, Fuchu-cho, Aki-gun, Hiroshima Prefecture Inside Mazda Co., Ltd. (56) References JP-A-62-17326 (JP, A) JP-A-52-70235 (JP, A) JP-A-52-85636 (JP, A) JP-A-57-191428 (JP, A) JP-A-56-77532 (JP, A) JP-A-55-128634 (JP, A) Japanese Utility Model Laid-Open No. 54-69222 (JP, U) ( 58) Field surveyed (Int.Cl. ⁷ , DB name) F02D 17/02 F02D 41/12 F02B 29/02

Claims (3)

(57) [Claims] 1. A fuel supply stopping means for arbitrarily stopping the supply of fuel to each cylinder in accordance with an operation state of an engine is provided, and the fuel supply stopping means is provided for each cylinder in a predetermined deceleration region. In the engine control device set to stop the fuel supply, the intake late closing means capable of arbitrarily performing the intake late closing according to the operation state of the engine, and the fuel supply stopping means for supplying fuel to all cylinders In the deceleration region where the supply is stopped, the intake late closing is performed in the partial region on the high load side while the intake late closing is performed in the low load side partial region. An engine control device, comprising: a control unit. 2. The engine control device according to claim 1, wherein the fuel supply stopping means is provided in a predetermined deceleration region adjacent to a deceleration region in which fuel supply to all cylinders is stopped from a high load side. The fuel supply to some of the cylinders is stopped, and the fuel supply to all the cylinders is stopped while performing the intake late closing, and the fuel supply to some of the cylinders is stopped. ,
An intake device for an engine, wherein the intake device is set between a region where fuel supply to all cylinders is stopped without performing intake late closing. 3. The engine control device according to claim 1, wherein the engine is a rotary piston engine, and the intake late closing means communicates the working chambers in the intake process of each cylinder. An engine control device comprising a pumping loss reducing unit including a communication passage and an on-off valve for opening and closing the communication passage.