JP2013060827A - Method of stopping internal combustion engine, internal combustion engine, and vehicle mounted with internal combustion engine - Google Patents

Abstract

Provided are an internal combustion engine stop method, an internal combustion engine, and a vehicle equipped with the same, which can suppress vibration after stopping the internal combustion engine with simple control and reduce the time required for the next start. .
After an engine 1 stop request, an intake throttle 30 reduces the amount of air supplied to each cylinder 20a to 20d to reduce the in-cylinder pressure of each cylinder 20a to 20d. In the process of decreasing, the final compression cylinder 20a that performs the compression stroke when the engine 1 stops and the final expansion cylinder 20b that is the firing order immediately before the final compressor cylinder 20a are predicted, and the intake air of the final expansion cylinder 20b is estimated. After completion, the supply amount of air sent from the intake throttle 30 to the final compression cylinder 20a is increased to increase the in-cylinder pressure of the final compression cylinder 20a.
[Selection] Figure 2

Description

  The present invention relates to a method for stopping an internal combustion engine, which suppresses vibration when the internal combustion engine is stopped with simple control, and shortens the next start time, an internal combustion engine, and a vehicle equipped with the same.

  When the operation of an engine (internal combustion engine) that employs electronic control is stopped, the fuel injection to each cylinder is stopped by the engine stop command, and the engine rotational speed gradually decreases to reach a complete stop. Also, in an engine equipped with an intake throttle (air conditioning device), the main component of the engine vibration moment caused by the in-cylinder pressure (secondary rotational component in an in-line four-cylinder engine) is the engine mount during the process of decreasing the engine speed. The in-cylinder pressure is reduced by reducing the opening of the intake throttle in the vicinity of the rotational speed that matches the resonance, thereby suppressing vibration when the engine is stopped.

  In such an engine stop process, the piston of the cylinder in the compression stroke is pushed up by the inertial force of the crank rotation motion and the piston reciprocating motion immediately before stopping, and the direction of motion is changed when the increased in-cylinder pressure balances with the inertial force. And start reverse rotation. Thereafter, the internal energy of the in-cylinder pressure is consumed by the reverse rotation kinetic energy and engine friction, and the cylinder is completely stopped.

  At this time, in some cases, in the other cylinders in the expansion stroke, the in-cylinder pressure is increased by the piston pushed up by the reverse rotation, and may stop after repeating the normal rotation and the reverse rotation.

  The piston position when the engine is stopped is determined by the in-cylinder pressure and engine friction immediately before stopping. Here, when considering the suppression of vibrations when the engine is stopped, the in-cylinder pressure is reduced when the engine stops because the rotational speed that coincides with the mount resonance described above (hereinafter referred to as the resonant rotational speed) exists below the idling rotational speed. It is desirable to reduce the excitation moment. Therefore, in order to simultaneously realize vibration suppression and start-up time reduction, control the in-cylinder pressure when passing through the resonance speed, and then stop the piston at a position where the ignition temperature can be reached at the first compression at the next start-up. There is a need.

  Therefore, an air amount adjusting means is provided, and the air amount adjusting means reduces the amount of air supplied to each cylinder after the engine stop request, and thereafter, at least one of the pressure from the air amount adjusting means to the engine or information relating to the pressure. A device that controls the air amount adjusting means so as to increase the air amount based on the above (for example, see Patent Document 1) or an air amount changing means that presets the intake air amount after the stop operation of the internal combustion engine. Reduce to a fixed amount and estimate the rotational load of the internal combustion engine, and then change the intake air amount to a predetermined amount set based on the estimated rotational load when the rotational speed of the internal combustion engine reaches the predetermined rotational speed There exists an apparatus (for example, refer patent document 2).

  However, these devices detect the in-cylinder pressure and the rotational load, calculate the air supply amount to the cylinder and control the air supply amount based on the calculated air supply amount in order to control the stop position of the piston. The apparatus is controlled, and a complicated process is required from detection to control.

JP 2006-083788 A Japanese Patent No. 4550627

  The present invention has been made in view of the above problems, and an object of the present invention is to achieve each cylinder of an internal combustion engine by a simple control at the time of stopping the internal combustion engine and at the rotation speed of the internal combustion engine that resonates with the engine mount. In-cylinder engine stop method, internal combustion engine, and the following, which can reduce the internal cylinder engine vibration, reduce the vibration of the internal combustion engine, and control the stop position of the piston to shorten the next start time Is to provide a vehicle.

  An internal combustion engine stop method according to the present invention for solving the above-mentioned object is an internal combustion engine in which an air supply device controls the stop position of the piston by adjusting the supply amount of air sent to a plurality of cylinders having pistons. In the engine stop method, after a request to stop the internal combustion engine, the air supply device decreases the amount of air supplied to each cylinder to reduce the in-cylinder pressure of each cylinder, thereby reducing the rotational speed of the internal combustion engine. In the process, when the internal combustion engine stops, a final compression cylinder that performs a compression stroke and a final expansion cylinder that performs an expansion stroke are predicted, and after the intake of the final expansion cylinder is completed, the air supply device In this method, the cylinder pressure of the final compression cylinder is increased by increasing the amount of air supplied to the compression cylinder.

  According to this method, firstly, the amount of air supplied to the cylinder by the air supply device is reduced, and the in-cylinder pressure of each cylinder is lowered. Therefore, when the rotational speed of the internal combustion engine passes through the resonant rotational speed, The rolling vibration moment can be reduced. Thereby, the vibration at the time of a stop of an internal combustion engine can be suppressed.

  Secondly, the final compression cylinder and the final expansion cylinder are predicted, and after the supply of air to the final expansion cylinder is completed, the supply amount of air to the final compression cylinder is increased, and the compression stroke of the final compression cylinder is increased. The in-cylinder pressure can be increased. Thereby, the piston of the final compression cylinder can be stopped at a position where the ignition temperature can be reached at the first compression due to the balance between the torque generated by the final compression cylinder, the torque generated by the final expansion cylinder, and the engine friction, The next starting time can be shortened.

  The above two functions and effects can be performed by simple control, and is particularly effective for an internal combustion engine that repeatedly stops and starts by an idling stop system.

  Further, in the above internal combustion engine stop method, after the intake stroke by the final intake valve performed by the final expansion cylinder until the internal combustion engine is stopped, the air supply device increases the supply amount of air, By increasing the air intake amount of the final compression cylinder by the intake stroke by the intake valve of the final compression cylinder, the in-cylinder pressure in the final compression stroke performed by the final compression cylinder before the internal combustion engine is stopped is increased.

  According to this method, in the final expansion cylinder, the in-cylinder pressure of the final expansion cylinder that expands when the internal combustion engine stops can be lowered to the end, and the vibration moment caused by the in-cylinder pressure can be reduced. At the same time, only the in-cylinder pressure of the final compression cylinder is controlled by the air supply device, and the piston can be stopped at a position where the ignition temperature can be reached at the first compression at the next start.

  An internal combustion engine for solving the above object includes a plurality of cylinders having pistons, an air supply device that adjusts the supply amount of air to be sent to each cylinder, and a control device that controls the air supply device. In the internal combustion engine in which the control device controls the stop position of the piston by adjusting the supply amount of air to be sent to each cylinder by the air supply device, and after the control device requests the stop of the internal combustion engine, the air supply Means for reducing the amount of air supplied to each cylinder to the device, and a final compression cylinder that performs a compression stroke and a final compression cylinder that performs an expansion stroke when the internal combustion engine stops in the process of reducing the rotational speed of the internal combustion engine A means for predicting an expansion cylinder and a means for increasing the supply amount of air to be sent to the final compression cylinder in the air supply device after the intake of the final expansion cylinder is completed.

  According to this configuration, the in-cylinder pressure of each cylinder can be reduced by reducing the amount of air supplied from the air supply device when passing through the resonance speed. Further, when the final compression cylinder performs the final compression stroke, the in-cylinder pressure of the final compression cylinder is increased and the torque in the reverse rotation direction is increased by increasing the amount of air supplied from the air supply device. Can do. Thus, with simple control, the in-cylinder pressure of each cylinder when the resonance rotational speed is passed is suppressed, and the piston is stopped at a position where the ignition temperature can be reached at the first pressure-compression at the next start-up. Can be stopped.

  In the internal combustion engine, air that the control device sends to the final compression cylinder to the air supply device after the intake stroke by the final intake valve that is performed before the internal combustion engine of the final expansion cylinder is stopped is completed. Cylinder in the final compression stroke performed by the final compression cylinder until the internal combustion engine is stopped by increasing the air intake amount of the final compression cylinder by the intake stroke by the intake valve of the final compression cylinder A means for increasing the internal pressure is provided.

  According to this configuration, completion of the intake stroke of the final expansion cylinder can be detected by a cam angle sensor provided in a normal internal combustion engine, and complicated calculations such as comparison of in-cylinder pressure and rotation speed are not performed. In addition, the timing for increasing the air supply amount of the air conditioning device can be determined. Therefore, the above-described effects can be obtained with simple control.

  In addition, in the internal combustion engine, the air supply device is formed by an intake throttle for adjusting an intake amount of air supplied to each cylinder, and the control device is configured so that the rotational speed of the internal combustion engine is From the idling rotational speed, the intake throttle is opened until the main component of the vibration generating moment of the internal combustion engine passes through the rotational speed that matches the resonance with the support device of the internal combustion engine, and the intake valve of the final expansion cylinder is closed. Provide means to reduce the degree.

  According to this configuration, the in-cylinder pressure of each cylinder can be reduced near the resonance rotational speed. As a result, the excitation of the mount resonance phenomenon can be suppressed and the vibration when the engine is stopped can be improved by reducing the rolling vibration moment generated due to the in-cylinder pressure in the engine rotation range where the resonance phenomenon becomes significant. it can. In addition, the in-cylinder pressures of the final expansion cylinder and the final compression cylinder can be adjusted, and the piston can be stopped at a position optimal for the next start.

  Further, by using the intake slot, an individual intake control device corresponding to each cylinder becomes unnecessary, the number of parts can be reduced, and the manufacturing cost can be reduced.

  A vehicle for solving the above problem is configured by mounting the internal combustion engine described above. According to this configuration, it is possible to reduce vibrations when the engine is stopped, and to shorten the start time that is particularly important in the idling stop system. The above-described internal combustion engine and control method can be applied to both gasoline engines and diesel engines. In the case of a gasoline engine, the piston stop position is set to a position suitable for starting combustion by spark ignition at the first compression at the next start.

  According to the present invention, the vibration of the internal combustion engine is reduced by reducing the in-cylinder pressure of each cylinder of the internal combustion engine at a rotational speed of the internal combustion engine that resonates with the engine mount when the internal combustion engine is stopped by simple control. In addition, the next starting time can be shortened by controlling the stop position of the piston.

1 is a cross-sectional view showing an internal combustion engine according to an embodiment of the present invention. 1 is a configuration diagram showing an internal combustion engine of an embodiment according to the present invention. It is the flowchart which showed the stop method of the internal combustion engine of embodiment which concerns on this invention. It is the figure which showed operation | movement of the intake throttle of the internal combustion engine of embodiment which concerns on this invention, an intake valve, and an exhaust valve. It is the figure which showed the time change at the time of the stop of the internal combustion engine of embodiment which concerns on this invention, (a) shows the rotation speed of an internal combustion engine, (b) shows the in-cylinder pressure of each cylinder, (c) It is the figure which showed the rotation direction of the piston.

  Hereinafter, a method for stopping an internal combustion engine, an internal combustion engine, and a vehicle equipped with the same according to embodiments of the present invention will be described with reference to the drawings. First, an internal combustion engine according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2. As shown in FIG. 1, an engine (internal combustion engine) 1 is fixed to a vehicle body (base) 2 via a rubber mount (mounting device) 3 and includes a cylinder block 11 and a cylinder head 12. The cylinder block 11 is provided with a crankshaft 13 and a first cylinder 20a (other cylinders are not shown), and the cylinder head 12 is provided with an intake manifold 14, a first cam mechanism 15, an exhaust manifold 16, and a second cam mechanism 17. . An ECU (control device) 40 is also provided.

  In the cylinder block 11, as shown in FIG. 2, four cylinders 20a to 20d are arranged in series. FIG. 1 shows one of the first cylinders 20a. Since the configuration of each of the cylinders 20a to 20d is the same, here, the first cylinder 20a will be described as an example.

  As shown in FIG. 1, the first cylinder 20a includes a piston 21a, a combustion chamber 22a, an injector (fuel injection device) 23a, an intake valve 24a, and an exhaust valve 25a. The piston 21a is joined to the crankshaft 13 via a connecting rod 26a, and slides up and down in the first cylinder 20a in the drawing by an intake stroke, a compression stroke, an expansion stroke, and an exhaust stroke that occur in the combustion chamber 22a. To do.

  The above configuration can use a well-known engine and is not limited to the above configuration. For example, an in-line 6-cylinder engine may be used, and the number of cylinders and the cylinder arrangement of the engine are not limited to in-line 4 cylinders. Moreover, it is applicable not only to a diesel engine but also to a gasoline engine. In addition, the intake valve 24a and the exhaust valve 25a may be formed by electromagnetic valves.

  As shown in FIG. 2, the intake manifold 14 includes an intake pipe 14a, an intake chamber 14b, and a supply pipe 14c. The intake pipe 14a is a pipe that takes air outside the vehicle into the intake manifold 14, and the intake chamber 14b is a communication passage with a supply pipe 14c that sends the air taken from the intake pipe 14a to each cylinder.

  In the intake pipe 14a, an intake throttle (air conditioning device) 30 is provided in the vicinity of the intake chamber 14b. The intake throttle 30 includes a throttle valve 31 and a throttle motor 32. By opening or closing the throttle valve 32 with the throttle motor 32, the amount of air supplied to each cylinder 20a to 20d is increased or decreased to change the air ratio of each cylinder 20a to 20d. The in-cylinder pressure of 20a to 20d can be adjusted. The intake throttle 30 is not limited to the above configuration as long as it can suck air into the intake manifold 14 and adjust the amount of air supplied to each cylinder 20a to 20d.

  The ECU 40 is a control device called an engine control unit, and is a microcontroller that comprehensively performs electrical control in charge of controlling the engine 1 by an electric circuit. In an automatic vehicle, the ECU 40 stores optimum control values in all driving states, detects the state at that time with a sensor, selects an optimum value from stored data by an input signal from the sensor, and The mechanism is controlled. The ECU 40 also includes an idling stop system, and can stop the engine 1 according to the stop time of the vehicle.

  The ECU 40 controls the throttle motor 15 and the injectors including the injectors 23a of the cylinders 20a to 20d. In addition, information detected by each of the crank angle sensor 41, the cam angle sensor 42, the atmospheric pressure sensor 43, the intake air temperature sensor 44, the intake air amount sensor 45, and the pressure sensor 46 is received. As these sensors, sensors of known techniques can be used.

  The ECU 40 also includes means for stopping fuel supply to the cylinders 20a to 20d of each injector including the injector 23a and means for reducing the opening of the intake throttle 30 when receiving a request to stop the engine 1. The engine 1 stop request is a driver stop operation or a stop request by an idling stop system.

  In addition, the ECU 40 stops the engine 1 due to a change in the actual rotational speed detected from the crank angle sensor 41 of the engine 1 in the process of decreasing the rotational speed of the engine 1 (the rotational speed becomes 0). ) At times, means for predicting the final compression cylinder corresponding to the compression stroke. Here, the final compression cylinder will be described as the first cylinder 20a.

  In addition, the means for predicting the final compression cylinder 20a may predict the final compression cylinder by using a numerical rotation speed prediction model. Along with this means, there is also provided means for predicting a final expansion stroke corresponding to the expansion stroke when the engine 1 is stopped. This predicting means can also be predicted by the same method as the prediction of the final compression cylinder 20a.

  In the case of the inline 4-cylinder engine 1, the ignition order is the order of the second cylinder 20b, the first cylinder 20a, the third cylinder 20c, and the fourth cylinder 20d. The previous cylinder can be determined as the final expansion cylinder. Therefore, in this description, the second cylinder 20b, which is the firing order immediately before the final compression cylinder 20a, is defined as the final expansion cylinder 20b.

  Further, the ECU 40 determines whether or not the intake valve 24b of the final expansion cylinder 20b is closed based on the information detected from the cam angle sensor 42 in addition to the information detected by the crank angle sensor 41, and determines the final expansion cylinder. Means for increasing the opening of the intake throttle 30 after the 20b intake valve 24b is closed.

  According to the above configuration, the in-cylinder pressure of each of the cylinders 20a to 20d can be reduced by reducing the opening of the intake throttle 30 until the intake process of the final expansion cylinder 20b is completed from the stop request of the engine 1. . The rotational speed of the engine 1 (hereinafter referred to as the resonant rotational speed R1) in which the main components of the mount resonant frequency of the rubber mount 3 and the rolling excitation moment coincide with each other is in the range of 0 to the idling rotational speed. In the vicinity of the resonance rotational speed R1, the in-cylinder pressure is lowered in the range of the engine 1 rotational speed where the resonance phenomenon becomes significant (hereinafter referred to as the vibration control rotational range A1), and rolling occurs due to the in-cylinder pressure. The vibration moment can be reduced and the excitation of the mount resonance phenomenon can be suppressed. Thereby, the vibration at the time of the stop of the engine 1 can be suppressed.

  In addition to the above-described effects, the in-cylinder pressure of the final compression cylinder 20a is increased by increasing the opening of the intake throttle 30 after the intake stroke of the final expansion cylinder 20b is completed, thereby increasing the in-cylinder pressure of the final compression cylinder 20a. Torque can be increased. The torque acts so as to stop the engine 1, whereby the piston 21a of the final compression cylinder 20a can be stopped at an optimal position for the next start. Therefore, the next start time can be shortened. The optimum stop position of the piston 21a is a position where the ignition temperature can be reached at the first compression at the next start, and is preferably between the bottom dead center and the middle of the process.

  In addition, the control for obtaining the above effect reduces the opening degree of the intake throttle 30 after receiving the stop request, and increases the opening degree of the intake throttle 30 after the intake valve 24b of the final expansion cylinder 20b is closed. Therefore, it can be performed with simple control without requiring complicated calculation. Further, it is not necessary to detect the in-cylinder pressures of the cylinders 20a to 20d and individually control the in-cylinder pressures of the cylinders 20a to 20d.

  Next, a method for stopping an internal combustion engine according to an embodiment of the present invention will be described with reference to FIG. In the internal combustion engine stop method S10, first, step S11 is performed to determine whether or not a stop request for the engine 1 has been made. The engine 1 is requested to be stopped by a driver's stop operation and by an idling stop system. If it is determined that there is a request to stop the engine 1, then step S12 is performed to stop the fuel supply from the injectors including the injector 23a to the cylinders 20a to 20d. Since the fuel supply is stopped in step S12, the engine speed gradually decreases. Next, step S13 for reducing the opening of the intake throttle 30 is performed. Since the opening degree of the intake throttle 30 is reduced in step S13, the supply amount of air supplied to each cylinder 20a to 20d is reduced, and the in-cylinder pressure is reduced.

  Next, step S15 for predicting the final compression cylinder corresponding to the compression stroke when the engine 1 is stopped is performed. Here, the first cylinder 20a is the final compression cylinder 20a. In this step S15, the final compression cylinder is predicted from the time change of the actual rotational speed. This method calculates, for example, how much the actual rotational speed has decreased per unit time, and how many cycles are performed before the actual rotational speed becomes 0, thereby predicting the final compression cylinder It is a method to do. Further, a method of predicting the rotation speed prediction model expressed in numerical formula and the actual rotation speed can be used. This step S15 is not limited to the above method as long as the final compression cylinder can be predicted.

  When the final compression cylinder 20a is predicted, step S16 is performed to determine the final expansion cylinder whose firing order of the final compression cylinder 20a is one before. Here, the second cylinder 20b is the final expansion cylinder 20b.

  Next, step S17 is performed to determine whether or not the rotation speed of the engine 1 detected by the crank angle sensor 41 is smaller than the lower limit of the vibration control rotation range A1. In step S17, the vibration control rotation range A1 is determined in advance and registered in the ECU 40. This vibration control rotation range A1 is determined as the rotation speed range of the engine 1 in which the resonance phenomenon becomes remarkable in preliminary experiments or numerical simulations since the resonance rotation speed R1 is in the range of 0 to idling rotation speed.

  In the control of the present invention, the control mode is determined by comparing the vibration control rotation range A1 and the actual rotation speed detected from the crank angle sensor 41, and at least the vibration control rotation range A1 from the stop request of the engine 1 is determined. Control is performed by reducing the opening of the intake throttle 30 up to the lower limit.

  Next, when it is determined that the actual rotational speed of the engine 1 has become smaller than the vibration control rotational range A1, step S18 for detecting the final cycle of the final expansion cylinder 20b is performed. Next, step S19 for detecting that the intake valve 24b of the final expansion cylinder 20b is closed is performed. In step S19, it can be detected from the information detected by the cam angle sensor 42 that the intake valve 24b is closed. When the intake valve 24b is closed, next, step S20 for increasing the opening of the intake throttle 30 is performed. By this step S20, the final compression cylinder 20a increases the amount of air supplied and increases the in-cylinder pressure due to the increase in the opening of the intake throttle 30.

  Here, step S20 will be described with reference to FIG. The opening of the intake throttle 30 is reduced until the final intake stroke of the final expansion cylinder 20b is completed, that is, until the intake valve 24b of the final expansion cylinder 20b is closed. Therefore, the torque fluctuation in the compression stroke and the expansion stroke of the final expansion cylinder 20b is small. When the intake valve 24b of the final expansion cylinder 20b is closed, the intake throttle 30 is opened to increase the amount of air supplied to the final compression cylinder 20a during the compression stroke, thereby reducing the in-cylinder pressure in the compression stroke of the final compression cylinder 20a. Can be bigger.

  Next, step S21 is performed to determine whether or not the in-cylinder pressure of the final compression cylinder 20a is the in-cylinder pressure necessary for the target stop position of the piston 21a. If the current in-cylinder pressure is the in-cylinder pressure required for the target stop position, the process proceeds to step S23 without correcting the opening of the intake throttle 30. If the current in-cylinder pressure is not the in-cylinder pressure required for the target stop position, step S22 for correcting the target opening of the next intake throttle 30 is performed.

  The correction of the target opening degree in step S22 is performed based on numerical values detected by the atmospheric pressure sensor 43, the intake air temperature sensor 44, the intake air amount sensor 45, and the pressure sensor 46. The piston 21a is pushed up by the inertial force of the crank rotation motion and the piston reciprocating motion, and when the cylinder pressure that has increased is balanced with the inertial force, the piston 21a changes its direction of motion and starts reverse rotation. Is consumed with reverse kinetic energy and engine friction. Therefore, the in-cylinder pressure necessary for the target stop position is calculated in consideration of the engine friction.

  The difference between the in-cylinder pressure required for the target stop position and the actual in-cylinder pressure detected by the pressure sensor 46 is calculated. The amount of intake air that can correct the difference is determined from information detected by the atmospheric pressure sensor 43, the intake temperature sensor 44, and the intake air amount sensor 45. Based on the determined intake amount, the opening of the intake throttle 30 is increased or decreased to correct the in-cylinder pressure of the final compression cylinder 20a.

  More specifically, the stop position of the piston 21a can be controlled by the balance between the torque generated by the final compression cylinder 20a, the torque generated by the final expansion cylinder 20b, and the engine friction. Here, since the torque generated by the final compression cylinder 20a and the final expansion cylinder 20b is based on the force acting on the piston 21a by the in-cylinder pressure, the intake air amount is adjusted by the intake throttle 30 to control the in-cylinder pressure. To control the stop position.

  When the in-cylinder pressure is p, the cylinder volume is v, and the polytropic index is n, the polytropic change is expressed by the following formula 1 from the thermodynamic relationship.

If the in-cylinder pressure p and the cylinder volume v at a certain time are determined, the in-cylinder pressure p at the time of stopping becomes equal to the atmospheric pressure detected by the atmospheric pressure sensor 43, so that the cylinder volume v is determined, and the cylinder volume v and the bore cross-sectional area are determined. The crank angle, that is, the stop position of the piston 21a can be calculated from the stroke and the compression ratio. Here, since the polytropic index n is affected by the temperature, the polytropic index n is corrected by the intake air temperature detected by the intake air temperature sensor 44.

  The intake amount by the intake throttle is calculated using Formula 1 and the outputs of the sensors 41 to 46.

  Then, step S23 in which the piston 21a of the final compression cylinder 20a stops at the target stop position is performed, and the process is completed. This target stop position is a position at which the ignition temperature can be reached at the first compression at the next start, and is preferably between the top dead center, the middle of the bottom dead center, and the bottom dead center.

  According to the above-described method for stopping the internal combustion engine, by controlling the opening degree of the intake throttle 30 in the vibration control rotation range A1, the rolling vibration moment generated due to the in-cylinder pressure is reduced, thereby reducing the mount resonance. Excitation of the phenomenon can be suppressed, and vibration when the engine 1 is stopped can be improved. In addition, by adjusting the cylinder pressures of the final expansion cylinder 20b and the final compression cylinder 20a in the stop control rotation range A1, the piston 21a can be stopped at an optimum position for the next start. The start-up time, which is particularly important in the stop system, can be shortened.

  Further, the above-described effects can be obtained only by controlling the intake throttle 30. Therefore, control can be facilitated as compared with the conventional method.

  Next, the relationship between the rotational speed and the in-cylinder pressure that coincide with the passage of time when the engine 1 according to the embodiment of the present invention is stopped will be described with reference to FIG. Here, the time when the engine 1 is requested to stop is t1, the time when the actual rotational speed reaches the resonance rotational speed R1, t2, the time when the intake valve 24b of the final expansion cylinder 20b is closed is t3, and the engine 1 is stopped. Let time be t4. As shown to (a) of FIG. 5, ECU40 stops the fuel supply to each cylinder 20a-20d from the injector containing the injector 24a from time t1. Thereby, the rotation speed of the engine 1 gradually decreases. At the same time, the opening degree of the intake throttle 30 is reduced. Thereby, as shown in FIG. 5B, the amount of air supplied to each of the cylinders 20a to 20d decreases, and the in-cylinder pressure decreases.

  As shown in FIG. 5A, it can be seen that the in-cylinder pressures of the cylinders 20a to 20d are low in the vibration control rotation range A1 in which the resonance phenomenon becomes remarkable. Thereby, the resonance with the rubber mount 3 can be reduced by suppressing the rolling moment caused by the in-cylinder pressure. The opening degree of the intake throttle 30 is kept closed until time t3.

  By increasing the opening of the intake throttle from time t3, as shown in FIG. 5B, the in-cylinder pressure of the final compression cylinder 20a increases. As a result, as shown in FIG. 5C, torque in the reverse rotation direction is generated, and the piston 21a can be stopped at a predetermined position.

  According to the above-described operation, the piston 21a is predetermined so that the excitation of the mount resonance between the engine 1 and the rubber mount 3 can be suppressed and the next start time can be shortened only by controlling the opening of the intake throttle 30. You can stop at the position. Further, since the in-cylinder pressures of the cylinders 20a to 20d can be adjusted using one intake throttle 30 without being individually controlled, the control can be easily performed. In addition, the control for stopping the piston 21a at a predetermined position can be simplified. This can be achieved by only controlling the intake throttle 30 and by increasing the opening of the intake throttle 30 when the intake valve 24b of the final expansion cylinder 20b is closed.

  The embodiment according to the present invention has been described by taking a diesel engine as an example, but can also be applied to a gasoline engine. In the case of a gasoline engine, the stop position of the piston is set to a position suitable for starting combustion by spark ignition at the first compression at the next start.

  A vehicle equipped with the engine 1 can reduce the vibration when the engine 1 is stopped, and can shorten the start time that is particularly important in the idling stop system.

  The internal combustion engine of the present invention reduces the rolling vibration moment generated due to the in-cylinder pressure, improves the vibration when the internal combustion engine is stopped, and stops the piston at the optimum position for the next start. Since the starting time can be shortened, it can be used particularly for vehicles equipped with an idling stop system.

1 engine (internal combustion engine)
2 Body (base)
3 Rubber mount (mounting device)
11 Cylinder block 12 Cylinder head 13 Crankshaft 14 Intake manifold 15 First cam mechanism 16 Exhaust manifold 17 Second cam mechanisms 20a to 20d Cylinder 21a Piston 22a Combustion chamber 23a Injector (fuel injection device)
24a Intake valve 25a Exhaust valve 30 Intake throttle 40 ECU (control device)
41 Crank angle sensor 42 Cam angle sensor

Claims (6)

In the internal combustion engine stop method in which the air supply device adjusts the supply amount of air to be sent to a plurality of cylinders having pistons, and controls the stop position of the pistons.
After the request to stop the internal combustion engine, the air supply device reduces the supply amount of air sent to each cylinder to reduce the in-cylinder pressure of each cylinder,
Predicting a final compression cylinder that performs a compression stroke and a final expansion cylinder that performs an expansion stroke when the internal combustion engine stops in the process of reducing the rotational speed of the internal combustion engine;
After the intake of the final expansion cylinder is completed, the internal combustion engine is stopped by increasing the supply amount of air sent from the air supply device to the final compression cylinder to increase the in-cylinder pressure of the final compression cylinder. Method.   After the intake stroke by the final intake valve performed by the final expansion cylinder until the internal combustion engine is stopped, the air supply device increases the supply amount of air, and the intake stroke by the intake valve of the final compression cylinder 2. The internal combustion engine stop according to claim 1, wherein an air intake amount of the final compression cylinder is increased to increase an in-cylinder pressure in a final compression stroke performed by the final compression cylinder before the internal combustion engine is stopped. Method. A plurality of cylinders having pistons, an air supply device that adjusts the supply amount of air to be sent to each cylinder, and a control device that controls the air supply device, the control device including the cylinders in the air supply device In the internal combustion engine that controls the stop position of the piston by adjusting the supply amount of air sent to
Means for reducing a supply amount of air sent to each of the cylinders to the air supply device after the control device requests to stop the internal combustion engine;
Means for predicting a final compression cylinder that performs a compression stroke and a final expansion cylinder that performs an expansion stroke when the internal combustion engine stops in the process of reducing the rotational speed of the internal combustion engine;
An internal combustion engine comprising: means for increasing a supply amount of air to be sent to the final compression cylinder in the air supply device after the intake of the final expansion cylinder is completed.   The control device increases the supply amount of air sent to the final compression cylinder to the air supply device after the intake stroke by the final intake valve to be performed before the internal combustion engine of the final expansion cylinder is stopped is completed. Means for increasing the in-cylinder pressure in the final compression stroke performed by the final compression cylinder before the internal combustion engine is stopped by increasing the air intake amount of the final compression cylinder by the intake stroke by the intake valve of the final compression cylinder; The internal combustion engine according to claim 3. The air supply device is formed by an intake throttle for adjusting the intake amount of air supplied to each cylinder,
The control device passes the rotational speed at which the internal combustion engine has a rotational speed at which the main component of the vibration generating moment of the internal combustion engine coincides with the resonance with the support device of the internal combustion engine from the idling rotational speed. 5. The internal combustion engine according to claim 3, further comprising means for reducing the opening of the intake throttle until the intake valve of the cylinder is closed.   A vehicle comprising the internal combustion engine according to any one of claims 3 to 5.