JP2013060887A - Method for controlling idling stop and idling stop system of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for controlling idling stop and idling stop system of an internal combustion engine that can promptly restart the same from an auto-stop state compared to the conventional restart.SOLUTION: When a restart is requested before an engine 1 completely stops, a pinion 5 of a starter is projected outward immediately before the engine 1 completely stops to mesh with a ring gear 4 that is coupled to a crankshaft 2 of the engine 1, and then the engine determines a cylinder 10 and a crank angle when stopped. After the engine 1 completely stops, the ring gear 4 is rotated by the pinion 5 to change a crank angle of a cylinder 10 which self ignites subsequent to the cylinder 10, which has been determined, to an angle of a closed timing of an intake valve.

Description

  TECHNICAL FIELD The present invention relates to an idling stop control method and an idling stop system for an internal combustion engine, and more specifically, an idling stop control for an internal combustion engine that can be restarted more reliably and more quickly than before when the engine is automatically stopped. The present invention relates to a method and an idling stop system.

  In recent years, in order to reduce fuel consumption and prevent environmental deterioration due to exhaust gas, automobile engines have been stopped to reduce fuel consumption by stopping the engine when the vehicle is parked at a signal or other conditions. It is equipped with a so-called idling stop mechanism that draws the driver's intention to start from the brake pedal, clutch pedal, shift operation, etc. and restarts the engine.

  As a technique for shortening the restarting time of the engine, a technique has been developed in which combustion at the start is quickly performed by stopping at an appropriate crank position when the engine is stopped. In addition, as a technique for enabling restart before completely stopping, starter motors that can separately operate the start-up of the starter pinion and the rotational drive have appeared.

  As an example of using such a starter motor, for example, an engine automatic stop that predicts a change in the rotation speed of the engine and pushes the pinion toward the ring gear in accordance with the synchronization of the rotation speed and the rotation speed of the pinion. A restart device has been proposed (see Patent Document 1).

  However, in the engine automatic stop / restart apparatus described above, if the cylinder in the first compression stroke at the time of restart cannot obtain sufficient in-cylinder pressure required for fuel self-ignition, restart is performed. May be delayed.

Japanese Patent No. 4214401

  An object of the present invention is to provide an idling stop control method and an idling stop system for an internal combustion engine that can perform restart at the time of automatic engine stop more quickly than before.

  An idling stop control method for an internal combustion engine according to the present invention that achieves the above-described object is an idling stop system in which fuel supply to the engine is stopped by a stop request generated during operation of the engine and a starter is started by a restart request. An idling stop control method for an internal combustion engine comprising: the starter pinion popping out immediately before the engine is completely stopped when the restart request is generated before the engine is completely stopped. The cylinder is engaged with a ring gear connected to the crankshaft, and the cylinder and crank angle when the engine is stopped are determined. After the engine is completely stopped, the crank angle of the cylinder that self-ignites next to the cylinder closes the intake valve. Rotating the ring gear with the pinion to change until timing It is an feature.

但し、D：シリンダ内径、L：コンロッド長さ、R：クランク半径、m_rec：往復部質量、P₀：インマニ圧力、κ：比熱比、Vs：隙間容積、V₀：下死点でのシリンダ容積、θ：クランク角度、ψ：コンロッド−シリンダ軸間角度、をそれぞれ示す。 In the above idling stop control method for the internal combustion engine, when the restart request is generated before the engine is completely stopped, the inertia I and the friction torque T of the crankshaft corresponding to the measured value of the water temperature or oil temperature of the engine. _f is determined, and the angular acceleration α of the crankshaft obtained by the following formulas (1) to (7) is integrated over a predetermined period from the time when the restart request is generated, so that the estimated future rotation of the crankshaft The speed Ne is calculated, the pinion is driven to rotate, and the future estimated rotational speed Ns is determined. At the time Ts when the estimated rotational speed Ne of the crankshaft is equal to or less than the estimated rotational speed Ns of the pinion. The pinion is pushed out and meshed with a link gear connected to the crankshaft.

However, D: cylinder bore, L: connecting rod length, R: crank radius, m _rec: reciprocating unit mass, P _0: intake manifold pressure, kappa: specific heat ratio, Vs: clearance volume, V _0: the cylinder at the bottom dead center Volume, θ: crank angle, ψ: connecting rod-cylinder shaft angle, respectively.

  The value obtained by subtracting the estimated rotation speed Ns of the pinion from the estimated rotation speed Ne of the crankshaft is preferably set to 0 rpm or more.

  Furthermore, it is desirable to start pushing out the pinion after a predetermined movement time Tr from when the pinion is pushed out to mesh with the ring gear from time Ts.

  In order to achieve the above object, an idling stop system for an internal combustion engine according to the present invention is an internal combustion engine that stops fuel supply to the engine by a stop request generated during operation of the engine and starts a starter by a restart request. The idling stop system includes a crank sensor for determining a stroke of each cylinder of the engine, and a control unit, and the control unit is configured to perform the restart request when the restart request is generated before the engine is completely stopped. Just before the engine is completely stopped, the pinion of the starter pops out and meshes with a ring gear connected to the crankshaft of the engine, and the cylinder and crank angle when the engine is stopped are determined from the measured values of the crank sensor, After the engine is completely stopped, the crank angle of the cylinder that self-ignites next to the cylinder is To vary until the timing of closing, it is characterized in that rotating the ring gear by the pinion.

但し、D：シリンダ内径、L：コンロッド長さ、R：クランク半径、m_rec：往復部質量、P₀：インマニ圧力、κ：比熱比、Vs：隙間容積、V₀：下死点でのシリンダ容積、θ：クランク角度、ψ：コンロッド−シリンダ軸間角度、をそれぞれ示す。 The above idling stop system for an internal combustion engine is provided with measuring means for measuring the water temperature or oil temperature of the engine, and the control means, when a restart request is generated before the engine is completely stopped, is measured by the measuring means. The crankshaft inertia I and the friction torque _Tf corresponding to the above are determined, and the crankshaft angular acceleration α obtained by the following formulas (1) to (7) is determined for a predetermined period from when the restart request is generated. By integrating, the estimated future rotational speed Ne of the crankshaft is calculated, the pinion is rotationally driven and the estimated future rotational speed Ns is determined, and the estimated rotational speed Ne of the crankshaft is determined as the estimated rotational speed Ns of the pinion. The pinion is pushed out and meshed with the link gear at a time Ts that is equal to or less than the same value.

However, D: cylinder bore, L: connecting rod length, R: crank radius, m _rec: reciprocating unit mass, P _0: intake manifold pressure, kappa: specific heat ratio, Vs: clearance volume, V _0: the cylinder at the bottom dead center Volume, θ: crank angle, ψ: connecting rod-cylinder shaft angle, respectively.

  The idling stop system for the internal combustion engine described above can be applied to general internal combustion engines.

  According to the idling stop control method and idling stop system of the internal combustion engine of the present invention, the cylinder in the first compression stroke at the time of restart is determined, and the ring gear is rotated by a pinion after the engine is completely stopped. Since the crank angle of the cylinder is changed until the intake valve closes, the cylinder in the first compression stroke at the time of restart can obtain a sufficient in-cylinder pressure required for fuel self-ignition. Therefore, the restart at the time of the automatic engine stop can be performed more quickly than before.

It is a block diagram which shows the structure of the idling stop system of the internal combustion engine which consists of embodiment of this invention. It is a flowchart explaining the control method of the idling stop of the internal combustion engine which consists of the 1st Embodiment of this invention. It is a graph which shows the time-dependent change of the engine speed of the 1st cylinder. It is a graph which shows a time-dependent change of the in-cylinder pressure of the 1st cylinder and the 4th cylinder. It is a schematic diagram explaining the relationship of the crank angle of the 1st cylinder and the 3rd cylinder. It is a flowchart explaining the control method of the idling stop of the internal combustion engine which consists of the 2nd Embodiment of this invention. It is a graph explaining the time-dependent change of the rotational speed of an engine and a pinion in the control method of FIG. It is a graph which shows an example of the relationship between the engine water temperature and friction.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 shows the configuration of an idling stop system for an internal combustion engine according to an embodiment of the present invention.

  The idling stop system of the internal combustion engine includes a ring gear 4 connected around a crankshaft 2 of the engine 1 via a flywheel 3, a pinion 5 that can mesh with the ring gear 4, and a water temperature or oil of the engine 1. It has measuring means 6 for measuring temperature and control means 7.

  The engine 1 has a plurality (four in the example of FIG. 1) of cylinders 10 including cylinders 9 in which pistons 8 connected to the crankshaft 2 reciprocate. In the engine 1, the fuel self-ignites in the order of the first cylinder 10a → the third cylinder 10c → the fourth cylinder 10d → the second cylinder 10b.

  The pinion 5 is rotationally driven by a motor 11, and its rotating shaft 12 is configured to be extendable and contractable toward the ring gear 4 by an electromagnetic solenoid actuator 13. A reduction gear (not shown) is interposed between the motor 11 and the rotary shaft 12 of the pinion 5 so as to protect the motor 11 when high speed rotation is applied from the ring gear 4 to the pinion 5. Yes. The pinion 5, the motor 11, the actuator 13 and the like constitute a starter.

  The measuring means 6 for measuring the water temperature or oil temperature of the engine 1 is not particularly limited, but a sensor using a thermocouple or a thermistor is used. As the water temperature and the oil temperature of the engine 1, the temperatures of the cooling water and the engine oil (for example, values after the first-order lag filter and the moving average filter) are used, respectively.

  The control means 7 is composed of a CPU (Central Processing Unit) having a storage unit 14 composed of a non-volatile memory. Each of the motor 11, the actuator 13, the measurement means 6 and the ECU (Engine Control Unit) 15 of the engine 1 is provided. Are connected through signal lines 16a to 16d.

  The ECU 15 is connected to an electromagnetic valve 19 provided in a fuel supply pipe 18 that supplies fuel from the fuel tank 17 to the engine 1 through a signal line 16e, and responds to the stop request or restart request of the engine 1. The idling stop is performed mainly by opening or closing the electromagnetic valve 19. The engine 1 stop request is issued, for example, when some of items such as the vehicle speed (detected by the wheel speed sensor) and the battery voltage satisfy a predetermined condition. The engine restart request is issued, for example, when a gear position, a clutch pedal state, or the like satisfies a predetermined condition.

  Further, a crank sensor 20 with a reverse rotation detection function connected to the control means 7 by a signal line 16f is attached at a position facing the side surface of the flywheel 3 or the ring gear 4. As this crank sensor 20, what detects the unevenness | corrugation carved in the flywheel 3 surface and the number of teeth of the ring gear 4 with a Hall element or an electromagnetic pick-up can be illustrated. The rotation pulse detected by the crank sensor 20 is converted by the control means 7 into fluctuations in the rotation speed of the crankshaft 2 and the states (strokes) of the cylinders 10a to 10d.

  The control means 7, the motor 11, the actuator 13, the ECU 15, and the crank sensor 20 operate using the battery 21 as a power source. In FIG. 1, electrical wiring from the battery 21 is omitted.

  In the above configuration, the control unit 7 and the ECU 15 are separated, but the ECU 15 may be provided with the function of the control unit 7 together.

  In the idling stop system having such a configuration, a first idling stop control method in the case where a restart request is issued before the engine 1 completely stops will be described below based on the flowchart shown in FIG. To do.

  When the control means 7 receives a restart request issued before the engine 1 is completely stopped through the ECU 15 (S10), the control means 7 activates the actuator 13 to point the rotating or stopped pinion 5 toward the ring gear 4. Jump out and mesh (S20).

  Then, from the rotation pulse detected by the crank sensor 20, the reverse rotation of the engine 1 is detected by the reverse rotation detection flag as shown in FIG. In the ECU 15, the cylinder 10 is discriminated from the signals of the cam and the crankshaft 2 and the crank position is recognized. When the engine 1 is reversely rotated, the stop position (crank angle) is recognized by subtracting the count of the crank pulse. The cylinder 10 when the engine is stopped can be determined (S30). Here, the cylinder 10 is assumed to be the first cylinder 10a. Before the piston 8 reaches the compression top dead center of the first cylinder 10a, the piston 8 is pushed back by the reaction force due to the compression, and the flywheel 3 is reversed. Due to the reverse rotation of the flywheel 3, as shown in FIG. The piston 8 is pushed back by the reaction force due to such compression, and the flywheel 3 is stopped in balance with the compression of the cylinder 10 in front, and the crank angle at that time is stopped at substantially the same position. The position is about 70 degrees before the top dead center, although there are some differences depending on the model of the engine 1.

  After the engine 1 is completely stopped (S40), the cylinder 10 that self-ignites next to the cylinder 10 (the first cylinder 10a in this example) determined in step S30 is determined (S50), and the crank angle of the cylinder 10 is The ring gear 4 is forcibly rotated by the pinion 5 so as to change until the intake valve closes (S60).

  If the cranking of the engine 1 is started when the intake valve is closed in this way, sufficient air can be compressed to increase the in-cylinder pressure to a level necessary for self-ignition. Therefore, the cylinder in the first compression stroke at the time of restart can obtain a sufficient in-cylinder pressure necessary for self-ignition of the fuel. It can be done promptly.

The state of step S60 will be described based on FIG. 5 showing the angle timing around the crankshaft. In FIG. 5, it is assumed that the engine 1 rotates clockwise.
It is the third cylinder 10c that self-ignites next to the first cylinder 10a in which the piston 8 is stopped before the compression top dead center. The piston 8 of the third cylinder 10c is positioned 180 degrees opposite to the crankshaft 2. Therefore, by rotating the crankshaft 2 by 90 degrees via the ring gear 4 with the pinion 5, the piston 8 of the third cylinder 10c is brought to the timing at which the intake valve at the position immediately before the start of compression is closed.

  The rotation of the ring gear 4 by the pinion 5 is performed by applying a minute current to the starter motor 11 by duty control. The change in the crank angle during the rotation of the crankshaft 2 is counted by the crank sensor 20, and the application of current to the motor 11 is stopped when the specified crank angle is reached. At this time, in consideration of the delay time caused by the inertia of the crankshaft 2 from the stop of the current application to the motor 11 until the rotation of the crankshaft 2 stops, the current is applied before the specified crank angle is reached. Is preferably stopped. Such a delay time can be obtained in advance by experiments or the like.

  The second idling stop control method will be described below based on the flowchart shown in FIG. 6 and the graph shown in FIG. FIG. 7 is a graph showing temporal changes in the rotational speeds of the engine 1 (crankshaft 2) and the pinion 5 when a restart request is issued from the ECU 15 before the engine is completely stopped.

  In this second idling stop control method, the rotation of the rotating pinion 5 toward the ring gear 4 is set appropriately (S20), and the two are smoothly meshed to suppress the generation of abnormal noise. In addition, the starter can be prevented from being damaged.

  When the control means 7 receives a restart request issued before the engine 1 is completely stopped through the ECU 15 (S10), the control means 7 starts the motor 11 through the signal line 16a and starts to rotate the starter pinion 5 (S11). ), The measured value of the water temperature or oil temperature of the engine 1 is input through the signal line 16c (S12). At this time, the ECU 11 opens the electromagnetic valve 19 through the signal line 16 e to supply fuel to the engine 1.

Then, the inertia I and the friction torque T _f corresponding to the measured values are compared with the data table indicating the relationship between the water temperature or the oil temperature and the inertia and friction torque of the crankshaft 2 stored in advance in the storage unit 14. Is determined (S13). FIG. 8 illustrates the relationship between the water temperature and the friction torque. Such data is previously stored in the storage unit 14 in the form of a data table.

但し、D：シリンダ内径、L：コンロッド長さ、R：クランク半径、m_rec：往復部質量、P₀：インマニ圧力、κ：比熱比、Vs：隙間容積、V₀：下死点でのシリンダ容積、θ：クランク角度、ψ：コンロッド−シリンダ軸間角度、をそれぞれ示す。 Next, the angular acceleration α of the crankshaft 2 is calculated using the following formulas (1) to (7).

However, D: cylinder bore, L: connecting rod length, R: crank radius, m _rec: reciprocating unit mass, P _0: intake manifold pressure, kappa: specific heat ratio, Vs: clearance volume, V _0: the cylinder at the bottom dead center Volume, θ: crank angle, ψ: connecting rod-cylinder shaft angle, respectively.

  By integrating this angular acceleration α in a predetermined period from the time when the restart request is generated, a future estimated rotation speed Ne of the crankshaft 2 (for example, several cycles ahead) is calculated (S14). In the calculation of the estimated rotational speed Ne, the rotational speed of the flywheel 3 or the ring gear 4 detected by the crank sensor 20 is used as an initial value for starting integration.

  At the same time, the estimated rotational speed Ns of the pinion 5 for a certain time after the restart request is also calculated (S14). The estimated rotational speed Ns of the pinion 5 is obtained by referring to a data table stored in the storage unit 14 for the elapsed time from the start of the motor 11 and the voltage of the battery 21 obtained experimentally in advance. Desired.

Then, the projection of the pinion 5 starts from the time Ts until the estimated rotational speed Ne of the crankshaft 2 becomes equal to or less than the estimated rotational speed Ns of the pinion 5 (approximate width: N _th ) (Ne ≦ Ns + N _th ). Timing Tp is calculated (S15), and when Tp has elapsed from the occurrence of the restart request (S16), the actuator 10 is activated to cause the rotating pinion 5 to jump out toward the ring gear 4 (S20).

  Since steps S20 to 60 are the same as the first idling stop control method (see FIG. 2), description thereof is omitted.

  In this way, the pinion 5 is moved at an appropriate timing calculated by the predetermined formulas (1) to (7) in consideration of the actual specifications of the engine 1 based on the water temperature or the oil temperature indicating the actual state of the engine 1. Since it jumps out and meshes with the ring gear 4, the ring gear 4 and the pinion 5 mesh smoothly.

In the second idling stop control method, the width N _th approximated to the estimated rotational speed Ns of the pinion 5 is given, as shown in FIG. 7, when the pinion 5 actually rotates from the stationary state to the rotational speed Ns. This is because there is a time lag Td and variations until the value reaches. This time lag Td can be obtained in advance from the characteristics of the motor 11 and the voltage of the battery 21. In consideration of actual equipment specifications, operating conditions, and conditions such as variation in meshing operation between the pinion 5 and the ring gear 4, a value obtained by subtracting the estimated rotational speed Ns of the pinion 5 from the estimated rotational speed Ne of the crankshaft 2 (N For example, _th ) is preferably set to a value of 0 rpm or more.

  Furthermore, in practice, as shown in FIG. 7, there is a movement time Tr from when the operation command for the pinion 5 is issued until it reaches the ring gear 4, so that the operation of the pinion 5 is instructed in consideration of the delay time. It is desirable to do.

  Since the predetermined movement time Tr can be obtained in advance by experiments or the like, as shown in FIG. 7, the estimated rotational speed Ne of the crankshaft 2 is equal to or less than a value X that is the same as or approximated to the estimated rotational speed Ns of the pinion 5. What is necessary is just to make the rotating pinion 5 pop out when the point of time corresponding to the magnitude of the predetermined movement time Tr has elapsed from the time Ts until the rotation time reaches.

  The time lag Td described above is a very small time, but also includes a time lag from the energization of the motor 11 to the start of rotation due to a delay of a circuit or a relay. As a result, the ring gear 4 and the pinion 5 can be smoothly engaged with each other.

  The use of the idling stop control method and the idling stop system of the present invention is not limited to idling stop, and can be applied when the engine 1 is normally stopped / started. Further, the object is not limited to the engine 1 for automobiles, but may be a general internal combustion engine.

DESCRIPTION OF SYMBOLS 1 Engine 2 Crankshaft 3 Flywheel 4 Ring gear 5 Pinion 6 Measuring means 7 Control means 8 Piston 9 Cylinder 10, 10a, 10b, 10c, 10d Cylinder 11 Motor 12 Rotating shaft 13 Actuator 14 Memory | storage part 15 ECU
16a to 16f Signal line 17 Fuel tank 18 Fuel supply pipe 19 Electromagnetic valve 20 Crank sensor 21 Battery

Claims (7)

An idling stop control method for an internal combustion engine comprising an idling stop system that stops fuel supply to the engine by a stop request generated during operation of the engine and starts a starter by a restart request,
When the restart request is generated before the engine is completely stopped, the starter pinion is popped out immediately before the engine is completely stopped, and fitted to a ring gear connected to the crankshaft of the engine,
Determine the cylinder and crank angle when the engine is stopped,
An idling stop for an internal combustion engine, wherein the ring gear is rotated by the pinion so that a crank angle of a cylinder that self-ignites next to the cylinder changes after the engine is completely stopped until an intake valve is closed. Control method. When the restart request occurs before the engine completely stops, the inertia I and the friction torque T _f of the crankshaft corresponding to the measured value of the water temperature or oil temperature of the engine are determined, and the following formula ( By integrating the angular acceleration α of the crankshaft obtained in 1) to (7) over a predetermined period from the time when the restart request is generated, a future estimated rotational speed Ne of the crankshaft is calculated, The rotational speed Ns of the pinion is rotationally driven and the estimated rotational speed Ns in the future is determined. At the time Ts when the estimated rotational speed Ne of the crankshaft is equal to or less than the estimated rotational speed Ns of the pinion, the pinion is 2. The method of controlling an idling stop of an internal combustion engine according to claim 1, wherein the idling stop is pushed and meshed with a link gear connected to the crankshaft.

However, D: cylinder bore, L: connecting rod length, R: crank radius, m _rec: reciprocating unit mass, P _0: intake manifold pressure, kappa: specific heat ratio, Vs: clearance volume, V _0: the cylinder at the bottom dead center Volume, θ: crank angle, ψ: connecting rod-cylinder shaft angle, respectively.   The method for controlling an idling stop of an internal combustion engine according to claim 1 or 2, wherein a value obtained by subtracting the estimated rotational speed Ns of the pinion from the estimated rotational speed Ne of the crankshaft is 0 rpm or more.   The internal combustion engine according to any one of claims 1 to 3, wherein the push-out of the pinion is started when the pinion is pushed out from the time Ts and returned by a predetermined movement time Tr until the pinion is engaged with the ring gear. Idling stop control method. An idling stop system for an internal combustion engine that stops fuel supply to the engine by a stop request generated during operation of the engine and starts a starter by a restart request,
A crank sensor for determining the stroke of each cylinder of the engine, and a control means,
When the restart request is generated before the engine is completely stopped, the control means pops out the starter pinion immediately before the engine is completely stopped and meshes with a ring gear connected to the crankshaft of the engine. Let
Determine the cylinder and crank angle when the engine is stopped from the measured value of the crank sensor,
An idling stop for an internal combustion engine, wherein the ring gear is rotated by the pinion so that a crank angle of a cylinder that self-ignites next to the cylinder changes after the engine is completely stopped until an intake valve is closed. system. Measuring means for measuring the water temperature or oil temperature of the engine,
The control means determines an inertia I and a friction torque T _f of the crankshaft corresponding to a measured value of the measuring means when the restart request is generated before the engine is completely stopped, By integrating the angular acceleration α of the crankshaft obtained by (1) to (7) over a predetermined period from the time when the restart request is generated, a future estimated rotational speed Ne of the crankshaft is calculated, The rotational speed Ns of the pinion is rotationally driven and the estimated rotational speed Ns in the future is determined. At the time Ts when the estimated rotational speed Ne of the crankshaft is equal to or less than the estimated rotational speed Ns of the pinion, the pinion The idling stop system for an internal combustion engine according to claim 5, wherein the engine is pushed out and meshed with the link gear.

However, D: cylinder bore, L: connecting rod length, R: crank radius, m _rec: reciprocating unit mass, P _0: intake manifold pressure, kappa: specific heat ratio, Vs: clearance volume, V _0: the cylinder at the bottom dead center Volume, θ: crank angle, ψ: connecting rod-cylinder shaft angle, respectively.   The internal combustion engine provided with the idling stop system of the internal combustion engine of Claim 5 or 6.

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