JPH0626356A - Engine control device - Google Patents

Abstract

PURPOSE:To provide an engine control device capable of effectively preventing the generation of a torque shock at the speed reducing fuel cut-off time in an engine in which total cylinder fuel cut-off is performed in a specified speed reducing region. CONSTITUTION:A rotary piston engine RE is provided with an intake delay- closing means (pumping loss reducing means) formed of a communicating passage 24 and a switching valve 25, and intake delay-closing control is performed by opening/closing the switching valve 25 by a control unit 26. Fuel injection from fuel injection valves 13p, 13s is also controlled by the control unit 26 so as to perform fuel cut-off in a specified speed reducing region. A partial fuel cut-off region, a total cylinder fuel cut-off region by the opening of the switching valve 25, and a total cylinder fuel cut-off region by the closure of the switching valve 25 are set, and fuel cut-off is performed in this order at the speed reducing fuel cut-off time so as to prevent the generation of a torque shock.

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 which stops fuel supply to the engine in a predetermined deceleration region.

[0002]

2. Description of the Related Art In general, when decelerating an automobile, it is not necessary to generate torque in the engine, but it is sometimes preferable not to generate torque because an effective engine brake can be obtained. Therefore, a fuel injection type engine that uses a fuel injection valve to supply fuel to a combustion chamber is usually provided with a fuel supply stopping means for stopping the 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, the fuel consumption performance can be maximized and effective engine braking can be obtained. . However,
In this case, the engine torque has a significantly negative value when the fuel supply is stopped, which causes 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 (all cylinder fuel supply region),
Between the predetermined deceleration area (all cylinder fuel cut area) where fuel supply to all cylinders is stopped, a buffer area (partial cylinder fuel cut area) where only fuel supply to some cylinders is stopped is provided. There has been proposed a fuel supply stopping means which is provided so as to decrease the engine torque stepwise when the fuel supply is stopped at the time of deceleration to reduce the torque shock (for example, see JP-A-58-101234). ). When the operating state of the engine enters the idle region during such deceleration, fuel supply is restarted so that engine stall does not occur.

[0005]

FIG. 11 shows an example of engine torque in each region when a partial cylinder fuel cut region is provided between the normal region and the all cylinder fuel cut region in this way. . As is apparent from FIG. 11, even when the partial cylinder fuel cut region is provided, the engine torque in the all cylinder fuel cut region has a strong negative value, so that the partial cylinder fuel cut region and the all cylinder fuel cut region are There is a problem that a considerably large torque difference occurs between the two, and therefore the torque shock generated during deceleration cannot be suppressed sufficiently.

The present invention has been made in order to solve the above-mentioned conventional problems, and the fuel supply is stopped in an engine in which the fuel supply to all cylinders is stopped in a predetermined deceleration region. It is an object of the present invention to provide an engine control device that can effectively prevent the occurrence of torque shock at the time.

[0007]

[Means for Solving the Problems]
Therefore, as shown in FIG. 1, the first invention is to
The fuel supply to each cylinder can be stopped arbitrarily according to the operating condition.
And a fuel supply stopping means A capable of
In the predetermined deceleration region, the supply stopping means A causes the fuel to be supplied to each cylinder.
Control of an engine set to shut off supply
In the system, intake air arbitrarily according to the operating condition of the engine
Intake intake delay closing means B capable of performing late closing and fuel supply
The fuel supply to all cylinders is stopped by the supply stop means A.
Delayed intake closing is performed in the partial area on the high load side in the deceleration area.
On the other hand, in the partial area on the low load side
Late intake closing control for controlling the late intake closing means B so as not to
And means C are provided for the engine
Provide a control device.

A second aspect of the present invention is the engine control device according to the first aspect, wherein the fuel supply stopping means A is
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 cylinders is stopped, and the intake delay is closed. The region where the fuel supply to all cylinders is stopped is set between the region where the fuel supply to some of the cylinders is stopped and the region where the fuel supply to all cylinders is stopped without performing the intake retardation. An engine intake device is provided.

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

[0010]

EXAMPLES Examples 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 on the inner surface of the side housing 2p forming the side wall of the casing 1p is opened, the independent intake passage 4p is opened.
Mixture is sucked into each of the working chambers 5p, 6p, 7p from the rotor, compressed by the rotor 8p, ignited and burned by the two spark plugs 9p, and the inner circumference of the rotor housing 10p forming the peripheral wall of the casing 1p. When the exhaust port 11p opening on the surface communicates with the working chambers 5p, 6p, 7p, the process of exhausting combustion gas to an exhaust passage (not shown) is repeated. Along with this, the rotor 8p makes a planetary rotational motion around the eccentric shaft 12 while sliding its top part on the trochoidal inner peripheral surface of the rotor housing 10p, and the eccentric shaft 12 rotates with this planetary rotational motion. 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. The second cylinder S has basically the same configuration as the first cylinder P, and thus a 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 omitted.
The same number as that of the first cylinder P is attached to each member of the cylinder S, and the subscript thereof is s.

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

The fuel injection valves 13p and 13s are controlled by a control unit 26, which will be described later, and in a normal operating region, inject fuel with 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 shown by a region D in FIG. 5, and fuel is supplied to both cylinders P and S in a relatively strong deceleration region shown in 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 the region C, which is a relatively weak deceleration region set between the regions D and B. (Cylinder fuel cut).

The engine RE is supplied with air in the working chambers 5p to 7p (5s to 7s) of one cylinder P (S) at the beginning of the compression stroke in order to reduce pumping loss in a predetermined operation region. , The working chamber 5s of the other cylinder S (P) in the intake stroke
Pumping loss reducing means (intake late retarding means) for releasing in ~ 7s (5p-7s) is provided.

Specifically, the pumping loss reducing means is 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 is composed of a communication passage 24 which communicates with the port 23s and an opening / closing valve 25 which opens and closes the communication passage 24. And each communication port 23p, 23s,
The corresponding intake ports 3p and 3s are arranged on the leading side by a predetermined eccentric axis angle (for example, 30 to 50 °), so that the communication ports 23p and 23s are connected to the intake port 3p.
It is designed to be closed later than p, 3s by the eccentric axis angle (retarded intake closed). Therefore, the working chambers 5p to 7p (5s to 7s) communicating with the one communication port 23p (23s)
Is in the early stage of the compression stroke, the other communication port 23
The relation that the working chambers 5s to 7s (5p to 7p) communicating with s (23p) are in the intake stroke is always established, and therefore, when the opening / closing valve 25 is opened, the operation in the initial 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. 3 (a), when the working chamber 5p of the first cylinder P is in the initial stage of the compression stroke,
The working chamber 5s of the second cylinder S is in the intake stroke, and 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 brought into such a communicating state. During some time, the air is not compressed and therefore no compression resistance occurs. On the other hand, on the side of the working chamber 5s, the working chamber 5p
Since the air flows in through the intake air, the intake negative pressure is weakened and the suction resistance is reduced. In this way, the resistance of the eccentric shaft 12 is reduced and the pumping loss is reduced. After this, FIG.
As shown in (c), from the time when 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 the arrow Y in FIG. 3 (d).

Here, the on-off valve 25 is controlled by the control unit 26 and is opened in a predetermined operating region so that fuel consumption performance is improved by reducing pumping loss. Further, the on-off valve 25 is generally opened for the purpose of improving the fuel consumption performance as described above, and in the all-cylinder fuel cut region shown by the region B in FIG. 5, torque shock is generated due to fuel cut during deceleration. It is designed to be opened to prevent

The control unit 26 is a comprehensive control means of the engine RE including the "fuel supply stopping means" and the "intake intake late 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, Using the starter start signal output from the starter switch 29 as control information, fuel supply control or fuel supply stop control for the fuel injection valves 13p, 13s, the on-off valve 2
5, various controls such as opening / closing control are performed. However, in the following, only the fuel supply stop control during deceleration according to the present application and the opening / closing control of the on-off valve 25 related thereto according to the flowchart shown in FIG. explain.

When the control is started, various data such as the throttle opening and the engine speed are read in step # 1. Next, in steps # 2 to # 5, it is determined which one of the areas A to D or the idle area in FIG. 5 the engine RE is operating in. Specifically, if it is determined that the engine speed is less than R1 (NO in step # 2), the operating state of the engine RE is in the idle region.
At 8, normal fuel control is performed. That is, fuel is supplied to both cylinders P and S. Then, step # 11
Then, the on-off valve 25 is closed to stabilize the idle 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) Since the operating state is in the region D, normal fuel control is performed in step # 8. Then, the opening / closing valve 25 is closed in step # 11 in order to secure the engine output. Of course, the open / close valve 25 may be opened by another control not mentioned in this embodiment in order to improve the fuel efficiency. Then, the process returns to step # 1.

When the engine speed is R1 or higher (YES in step # 1), the throttle opening is TVO1 and S0.
If it is determined that the number of lines is less than or equal to the D3 line and exceeds the SD2 line (YES in steps # 3 and 4; step #
(NO in 5), which means that the operating state is in the region C, so that the partial cylinder fuel cut is performed in step # 7. Then, in order to improve the combustion stability, step # 1
The on-off valve 25 is closed at 1 and then the process returns to step # 1.

When the engine speed is R1 or more (YES in step # 1) and the throttle opening is determined to be TVO or less and SD2 line or less (YES in steps # 3, 4, and 5). ), Since the operating state is in the region B or the region A, the fuel cut for all cylinders is performed in step # 6. Then, in step # 9,
It is determined whether the throttle opening is SD1 line or more, and when it is determined that the throttle opening is SD1 line or more (YE
S), that is, when the logical condition as shown in FIG. 6 is satisfied for each switch, the operating state is in the region B. In this case, the pumping loss is reduced and the negative torque of the engine RE is reduced. Step # 1 to mitigate
At 0, the open / close valve 25 is opened. It should be noted that each switch is set with hysteresis as shown in FIG. 7 so that problems such as hunting do not occur. Then, the process returns to step # 1.

On the other hand, when it is determined in step # 9 that the throttle opening is less than the SD1 line (NO), the opening / closing valve 25 is closed in step # 11 in order to obtain effective engine braking. Then, the process returns to step # 1.

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

FIG. 9 shows changes with time of the throttle opening (H ₁ ) and the engine torque (H ₂ ) when fuel is cut during deceleration. As is clear from FIG. 9, since the engine torque is gradually decreasing, torque shock does not occur. In the conventional deceleration fuel stop control, as shown by the broken line H ₂ ', there is a part of the engine torque sharply drops, where torque shock occurs. As described above, according to the first embodiment, it is possible to effectively prevent the occurrence of torque shock when the fuel is cut during deceleration.

<Second Embodiment> The second embodiment will be specifically described below. In the second embodiment, the engine is a reciprocating engine and the intake retarding means is a variable valve timing mechanism, but the substantial function or effect is
Since the first embodiment is basically the same, the description of the points that are the same as 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 is provided via the intake port 32.
3, the mixture is sucked into the combustion chamber 34, the mixture is compressed by the piston 35, ignited and burned by the ignition plug 36, and when the exhaust valve 37 is opened, the combustion gas flows through the exhaust port 38. The process of discharging the gas to the exhaust passage 39 via the above is repeated. A catalytic 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 reciprocating motion is converted into rotational motion by the connecting rod 41, the crank pin 42, and the crank arm 43, and is transmitted to the crank shaft 44. It has become.

The intake valve 31 is opened and closed at a predetermined timing in synchronization with the crankshaft 44 by a plurality of intake valve cams 52 attached to the intake side camshaft 51. Similarly, the exhaust valve 37 is also opened and closed by a plurality of exhaust valve cams 54 attached to the exhaust side cam shaft 53. A variable valve timing mechanism 55 is provided for the intake camshaft 51, and the variable valve timing mechanism 55 delays the rotation phase of the intake camshaft 51 according to a signal applied from the control unit 60. You can do it. 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, it is possible to perform the intake late closing. That is, in the second embodiment, the variable valve timing mechanism 55 is the intake late closing means.

A common intake passage 61 is provided for supplying air to the engine CE.
From the upstream side in the air flow direction, the air cleaner 62
An air flow meter 63 and a throttle valve 64 are provided. The downstream end of the common intake passage 61 is connected to the surge tank 65, and the surge tank 65 is connected to the upstream end of the independent intake passage 33. 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 "fuel supply stopping means" and "intake intake late closing control means" described in the claims, and is substantially the same as that of the first embodiment. The similar fuel supply stop control and the intake late closing control are performed to effectively prevent the occurrence of torque shock when the fuel is cut during a predetermined deceleration.

As shown in FIG. 13, the variable valve timing mechanism 55 is a hydraulic variable valve timing mechanism in which the rotation of the timing gear 85 driven by the crankshaft 44 (see FIG. 12) is changed in order by the sleeve. It is adapted to be transmitted to the camshaft 51 via 84, the piston 83 and the hub 82. The journal portion 87 of the camshaft 51 is rotatably supported by the bearing portion 99 formed on the cylinder head 98. An inter-cam gear 8 is attached to the cam shaft 51 using a lock nut 89, and a seal member 100 seals between the cylinder head 98 and the spacer 86.

The piston 83 incorporated between the sleeve 84 and the hub 82 has a cylindrical structure which is divided into two parts, the front and rear parts, and the divided parts are connected to each other by a pin 90. Then, on the inner peripheral surface and the outer peripheral surface of the piston 83, the helical splines 91,
92 is formed. Where 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 constantly urged forward by a spring 95.

The hub 82 is fixed to the camshaft 51 by a fixing bolt 97 via a locking member 96.
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 biasing force of the spring 95, At this time, the hub 82 and the sleeve 84 relatively rotate in opposite directions by the action of the splines 91, 92, 93, 94. Therefore, the rotational phase between the camshaft 51 that integrally rotates with the hub 82 and the timing gear 85 that integrally rotates with the sleeve 84 shift, 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 restored.

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

[0033]

According to the first aspect of the present invention, when fuel is cut to the engine during deceleration, all cylinder fuel cut is first performed in the intake retarded closed state in which pumping loss is small, and then, The fuel cut of all cylinders is performed in a state where the intake air delay is released and the pumping loss is large. Therefore, the engine torque changes stepwise when the deceleration fuel is cut, and the occurrence of torque shock is prevented.

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

According to the third invention, basically, the same action and effect as those of the first or second invention can be obtained. further,
Since the engine is a rotary piston engine and the intake retarded closing means is composed of the communication passage and the opening / closing valve, the intake delayed closing means and the intake delayed closing control means have a very simple structure.

[Brief description of 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 communication state between cylinders of the rotary piston engine shown in FIG.

FIG. 4 is a flowchart showing 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 showing a logical configuration of each switch when the on-off valve is opened.

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

FIG. 8 is a diagram comparing engine torques in respective operating 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 operating 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 a side cross-sectional explanatory view of the variable valve timing mechanism of the engine shown in FIG.

[Explanation of symbols]

 RE ... Rotary piston engine CE ... Reciprocating engine P, S ... First and second cylinders 5p, 6p, 7p ... Operating chamber 5s, 6s, 7s ... Operating 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

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Reference number within the agency FI Technical indication location F02D 43/00 H 7536-3G (72) Inventor Susumu Inoue 3-1, Shinchi, Fuchu-cho, Aki-gun, Hiroshima Prefecture No. Mazda Co., Ltd.

Claims (3)

[Claims] 1. A fuel supply stopping means for arbitrarily stopping the fuel supply to each cylinder according to an operating state of the engine is provided, and the fuel supply stopping means supplies the fuel to each cylinder in a predetermined deceleration region. In an engine control device that is set to stop fuel supply, an intake late closing means that can arbitrarily perform an intake late closing according to the operating state of the engine, and a fuel supply stopping means that supplies fuel to all cylinders In the deceleration region where the supply is stopped, the intake retarded closing is controlled in the partial region on the high load side while the intake delayed closing is performed in the partial region on the low load side so that the intake retarded closing means is controlled. An engine control device comprising: a control means. 2. The engine control device according to claim 1, wherein the fuel supply stop means is arranged in a predetermined deceleration region adjacent to the deceleration region where fuel supply to all cylinders is stopped from the high load side. , The fuel supply to some cylinders is stopped, and the area where fuel supply to all cylinders is stopped while the intake air intake delay is performed is the area where fuel supply to some of the cylinders is stopped. ,
An intake system for an engine, characterized in that it is set between a region where fuel supply to all cylinders is stopped without performing late intake closing. 3. The engine control device according to claim 1 or 2, wherein the engine is a rotary piston engine, and the intake retarding means connects the working chambers in the intake stroke of each cylinder. An engine control device comprising pumping loss reducing means including a communication passage and an on-off valve that opens and closes the communication passage.