JP2626390B2 - Automotive engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automobile engine and, more particularly, to a vehicle engine having a structure capable of suspending operation of a valve device for intake and exhaust in a selected one of a plurality of cylinders. Automobile engine.

[0002]

2. Description of the Related Art Generally, in an automobile engine,
The maximum opening amount of the valve corresponds to the maximum lift amount from the cam profile of the valve opening / closing cam, and since this amount is always constant, the load from the engine speed and the throttle opening is not affected. At present, it is not possible to set an appropriate intake / exhaust efficiency. That is, for example, in the case of an engine that requires high-speed rotation, the above-described cam profile is set in consideration of increasing the intake ratio and the exhaust efficiency of the air-fuel mixture. Fuel consumption rate tends to be sacrificed. On the other hand, when the cam profile is set in consideration of the fuel consumption rate, the output may not be sufficiently obtained at the time of high-speed rotation or high-load operation.

In order to satisfy such operating conditions of the engine, it is necessary to satisfy both of the reduction of fuel consumption at low speed and low load operation and the securing of output at high speed and high load operation. A cam with a cam profile for low speed and high speed is prepared as a valve opening / closing cam, and a rocker arm provided with a cam follower that is in abutting contact with each of the cams, and a swing fulcrum of the arm is formed. The rocker shaft is separated from the rocker shaft, and the rocker shaft is integrally provided with a sub rocker arm that is in contact with the valve stem. And the uncoupled position are selected, and the swing of the rocker arm on the connected side is Structure so as to open and close control of the valve is transmitted to Kkaamu has been proposed (e.g., Japanese Patent Application 2-1821 is a prior application filed by the present applicant
No. 31). In this structure, in addition to switching the valve opening / closing amount by the valve opening / closing cam at the time of low-speed operation and high-speed operation, the connection of the plunger to each rocker arm is not performed, and so-called valve closing on the cylinder side is performed. It is also possible to stop the operation and close the cylinder.

[0004]

The above-mentioned cylinder rest state is as follows.
For example, in the case of a four-cylinder engine, the first cylinder and the fourth cylinder, which have the same piston stroke, correspond to the first cylinder and the fourth cylinder to reduce the fuel consumption. And the volume efficiency of the air in the cylinder corresponding to the load information is determined and the map is determined.

However, in an engine using such a cylinder deactivation system, for example, when the cylinder is switched from the cylinder deactivated state to the all cylinder state, the amount of intake air required for each cylinder increases and the negative pressure is reduced. On the other hand, while the tendency to increase is increased, there is actually a time delay until the intake pipe internal pressure becomes a predetermined negative pressure due to the capacity of the intake system. Therefore, when the state is switched to the all-cylinder state, if the change in the intake pipe pressure is obtained immediately, the air amount required for the combustion stroke in the cylinder can be set, but for the reasons described above. , In fact, because of the delay,
A large amount of air is instantaneously introduced, whereby the output during the explosion stroke becomes abnormally large, and may appear as a torque shock during a transition corresponding to switching to the all-cylinder state.

Accordingly, an object of the present invention is to solve the above-mentioned problem in an automobile engine in which a cylinder-stopping system can be set. An object of the present invention is to provide an automobile engine having a structure capable of preventing a shock from occurring.

[0007]

SUMMARY OF THE INVENTION In order to achieve this object, the present invention comprises a valve opening / closing cam provided with a cam profile for low speed and high speed, and switches a driven state of the cam on the rocker arm side. Thus, in an automobile engine equipped with a valve mechanism capable of setting a valve opening / closing amount and a valve rest state, a rotational speed sensor for detecting an engine rotational speed, and a volumetric efficiency of air in a cylinder according to a throttle opening. The boost pressure sensor for determining the pressure, an ignition timing setting device having an advance function, the rotation speed sensor, the boost pressure sensor are connected to the input side, and the output side, the drive unit of the valve mechanism and the A control unit to which an ignition timing setting device is connected, wherein the control unit uses load information based on engine speed and volumetric efficiency of air. A map that sets the all-cylinder state in which the valves are opened and closed for all cylinders and the closed-cylinder state by stopping the opening and closing of the valves for some of the cylinders, and the closed-cylinder state set by the above map An ignition retard map in which the retard amount is reduced to a reference ignition timing as the maximum number of strokes is increased immediately after the return according to the number of strokes when the cylinder is returned to the full cylinder state, and the boost pressure sensor And a boost correction map for correcting the amount of retard in a portion outside the switching range of the all cylinders / cylinder state obtained by the signal from the controller. When the cylinder is switched from the cylinder-stop state to the all-cylinder state, the retard amount of the ignition timing is set by the ignition retard map based on the number of strokes after returning to the full-cylinder state; and The Rita - against de weight, Bed - is characterized by changing the calculated ignition timing to de amount from the reference ignition timing - Rita obtained by multiplying the correction amount from the stringent correction map.

Further, according to the present invention, the boost correction map includes:
It is set for idle operation and acceleration, and the ignition timing in this state is set to be advanced with respect to the retard amount obtained from the ignition retard map. I have.

[0009]

According to the present invention, when the cylinder is switched from the closed cylinder state to the all cylinder state, the retard amount of the ignition timing is set according to the number of strokes from the point in time when the cylinder is switched to the all cylinder state. In particular, the maximum retard amount is set immediately after returning to the all cylinder state.

Further, according to the present invention, when the volumetric efficiency of air due to the boost pressure is minimum and maximum, in other words, during idling and acceleration, the amount of delay with respect to the ignition timing is reduced. Alternatively, without setting a delay amount, it is possible to prevent combustion instability and prevent ignition delay, thereby ensuring required output by promoting combustion.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be described below in detail with reference to FIGS.

FIG. 1 is a system configuration diagram of an automobile engine according to an embodiment of the present invention. In FIG. 1, an intake / exhaust port of an engine 1 is provided with a valve mechanism 2 described in the above specification. The hydraulic drive unit of the valve mechanism 2 is set to a working position by a control unit, which will be described later, and is operated to open and close the valve in all the cylinders and open and close the valve only in some of the cylinders. An operation for suspending the opening and closing of the valve in the cylinder is performed. On the other hand, a control unit (indicated by an indication "ECU" in the figure) 3 is constituted by a microcomputer for comprehensively performing various controls related to engine combustion such as setting of a fuel injection amount. The input side via an interface (not shown) is a rotation speed sensor 4 for detecting the engine rotation speed, and a boost pressure sensor for detecting the boost pressure located upstream of the intake port, as related to the present embodiment. 5, crank angle sensor 6,
A water temperature sensor 7 and a throttle position sensor 8 are connected to each other, and a hydraulic drive unit of the valve mechanism 2 and a distributor 9 as an ignition timing setting device are connected to the output side.

In the control section 3, the setting of all cylinders / closed cylinders is performed by a map (not shown) according to the engine speed 4 and the load based on the volumetric efficiency of air obtained by the boost pressure sensor 5. , But Figure 2
When returning from the cylinder-stop state to the all-cylinder state shown in (D), when the transition from the cylinder-stop state to the all-cylinder state occurs, the brake is stopped during a transition.
Due to the fact that the change in the strike pressure does not correspond (see FIG. 2 (C)), as shown by the solid line in FIG. 2 (A), the air introduced when the combustion stroke is performed by the ignition timing during normal operation As shown by the solid line in FIG. 2 (B), a sudden change in torque occurs due to the rapid increase in the amount.
In FIG. 2B, the ignition timing is retarded to suppress a sudden change in torque as shown by the broken line in FIG. 2B. Therefore, the control unit 3
As shown in FIG. 3, in accordance with the number of strokes after returning to the all-cylinder state, a retard amount that is maximized immediately after the return and is reduced as the number of strokes after the return increases is set. The ignition retard map described above is provided to adjust the retard amount with respect to the ignition timing during normal operation.

On the other hand, the control unit 3 includes the ignition retarder described above.
In addition to the boost map, as shown in FIG. 4, a booster for correcting the retard amount for a portion other than the range of the boost pressure normally used for switching between the full cylinder and the closed cylinder state. A correction map is provided. This boost correction map is used to correct the amount of retard by the ignition retard map so as to decrease the retard amount. When this boost correction map is used, the boost correction map is used during idling operation when the rotation of the engine is slow and reversely. There are times when acceleration accelerates the rotation. During idle operation, the ignition timing cannot be delayed to prevent combustion instability.At the time of acceleration, ignition delay due to a rise in intake pressure is prevented to obtain the output required for acceleration, that is, torque. For these reasons, it is desirable to reduce the retard amount of the ignition timing in any case to achieve a so-called posture in accordance with the ignition timing during normal operation. Therefore, the retard amount is corrected. It has become.
Accordingly, when the cylinder is switched from the cylinder-stop state to the all-cylinder state, a sudden change in torque during the transition is suppressed by retarding the ignition timing, and the retard is adjusted according to the operating conditions on the engine side. By correcting the amount, it is possible to maintain the operation of the engine according to the actual situation.

Since the present embodiment is configured as described above,
Now, the operation will be described with reference to a flowchart showing the operation of the control unit, as shown in FIG. FIG. 5 is for the case where the number of strokes after returning to all cylinders is 30 in the ignition retard map shown in FIG. That is, it is determined whether or not the cylinder is in the cylinder-stop state based on the volumetric efficiency of the air based on the engine speed and the boost pressure. It is determined whether or not the stroke corresponds to the number of strokes. If the number of strokes does not correspond to the number of strokes, it is determined whether or not the number of strokes has elapsed. If so, the number of strokes is counted up. The retard amount corresponding to the number of strokes is determined from the ignition retard map shown in FIG. The number of strokes after returning to the all-cylinder state at this time is counted based on the control unit 3 outputting a command to return to the all-cylinder state as a reference. In the case where the retard amount determined by the ignition retard map shown in FIG. 3 corresponds to the time of idling operation and the time of acceleration by the signal from the boost pressure sensor 5, FIG. The amount of correction of the retard amount is determined from the boost correction map shown in FIG. 4 and is multiplied by the above-described amount of retard to set the amount of retard at the present stage. The ignition advance amount is set by subtracting from the base advance angle used during operation and output to the distributor 9, and the ignition timing is set in the corresponding cylinder based on the signal from the crank angle sensor 6. Is done.

In the flow chart, when the cylinder is in the cylinder stall state, the ignition timing is set to a base advance angle used during normal operation.

The water temperature sensor 7 connected to the control unit 3 is connected to the boost correction map shown in FIG.
The throttle position sensor 8 is provided for detecting the cranking time when the strike pressure is low.
Is shown as a substitute for the boost pressure sensor 5.

[0018]

As described above, according to the present invention, when the state is switched from the cylinder-stop state to the all-cylinder state, the value becomes large during the transition and decreases according to the number of strokes after switching to the all-cylinder state. Since the ignition timing is retarded as described above, it is possible to set the ignition timing in accordance with the delay in the rise of the intake pipe internal pressure which occurs during the transition. Therefore, it is possible to execute the combustion stroke at the time when the intake pipe internal pressure has a sufficient tendency to reduce the pressure in the intake pipe and uniform air is introduced, thereby suppressing a sudden change in torque during execution of the combustion stroke. Thus, occurrence of torque shock can be prevented.

Further, according to the present invention, the ignition timing is controlled
When the engine is idling or accelerating, the retard amount can be reduced to perform the combustion stroke at or near the ignition advance angle used during normal operation, so that engine combustion is unstable. It is possible to prevent the occurrence of a situation in which an output that does not match the driver's will is obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a system configuration of an automobile engine according to an embodiment of the present invention.

FIG. 2 is a view showing a relationship among all cylinders / closed cylinders, a change in boost pressure, a change in torque, and an ignition timing for explaining a control method executed by a control unit in the system configuration shown in FIG. 1; FIG.

FIG. 3 is a diagram showing a map relating to a retard amount of an ignition timing set in a control unit in the system configuration shown in FIG. 1;

FIG. 4 is a diagram showing a map relating to a correction amount by a boost pressure with respect to a retard amount of an ignition timing set in a control unit in the system configuration shown in FIG. 1;

FIG. 5 is a flowchart for explaining the operation of a control unit in the system configuration shown in FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Engine 2 Valve mechanism 3 Control part 4 Speed sensor 5 Boost pressure sensor 9 Distributor

──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI Technical display location F02D 43/00 301 F02D 43/00 301Z

Claims (2)

(57) [Claims] 1. A valve opening / closing cam having a low-speed and high-speed cam profile set therein, and a driven state of the cam on the rocker arm side is switched.
For an automobile engine equipped with a valve mechanism that can set the opening and closing amount of the valve and the rest state of the valve, to determine the rotation speed sensor that detects the engine rotation speed and to determine the volumetric efficiency of air in the cylinder according to the throttle opening A boost pressure sensor, an ignition timing setting device having an advanced angle function, the rotation speed sensor and the boost pressure sensor are connected to an input side, and a drive unit of the valve mechanism and the ignition timing setting are connected to an output side. A control unit to which the device is connected, wherein the control unit is configured to open and close valves for all cylinders based on load information based on engine speed and volumetric efficiency of air. A map for setting the cylinder closed state by stopping the opening and closing of valves for some cylinders, and returning to the all cylinder state from the cylinder closed state set by the above map In accordance with the number of strokes in this case, it is obtained from an ignition retard map in which the retard amount is set to a maximum immediately after the return and is reduced with respect to the reference ignition timing as the number of strokes increases, and a signal from the boost pressure sensor. A boost correction map for correcting the retard amount in a portion outside the switching range of the all cylinders / cylinder rest state. When the state is switched from the state to the all-cylinder state, the retard amount of the ignition timing is set by the ignition retard map based on the number of strokes after the return to the all-cylinder state, and the retard amount is set to this retard amount. On the other hand, an engine for an automobile, wherein the ignition timing is changed by calculating a retard amount obtained by multiplying a correction amount from a boost correction map from a reference ignition timing. 2. The vehicle engine according to claim 1, wherein the boost correction map is set for idle operation and acceleration, and the ignition timing in this state is obtained from a ignition retard map. An automotive engine that sets the tendency to advance with respect to the amount of power.