JP4932022B2 - Engine start control device for idle stop car - Google Patents

Description

  The present invention relates to an engine start control device for an idle stop vehicle that starts an engine with a gear meshing type start device.

  As a means for suppressing wasteful fuel consumption, there is an idle stop vehicle having an idle stop function. The idle stop function stops the operation of the engine when a predetermined stop condition is satisfied when the traveling vehicle is stopped, and then starts the vehicle when the predetermined start condition is satisfied. This is a function that restarts.

Normally, for starting the engine, a starter that transmits power to the engine via a gear transmission mechanism such as a reduction gear type is used as a starting device.
Generally, a starter motor in which a pinion gear is assembled to an output shaft is used for the starter. Then, the pinion gear of the starter motor is engaged with the ring gear on the outer periphery of the flywheel of the engine, and the power is transmitted from the starter motor to the flywheel so that the engine is started, and after the engine is started, the pinion gear is detached from the ring gear. is there.

In the idling stop vehicle, the engine is automatically restarted by such a starter. By the way, when the engine is started in the cold state, the amount of torque required for starting is considerably larger than that in the warm state due to an increase in a related amount (friction) related to the rotational resistance of the engine at this time.
Therefore, an idle stop vehicle indirectly uses the physical phenomenon that the magnitude of the related amount (friction) related to the rotational resistance is correlated with the temperature, and indirectly based on the temperature information of the engine coolant. A technique for estimating the viscosity of a lubricating oil has been proposed (see, for example, Patent Document 1).

In the idle stop vehicle described in Patent Document 1, the magnitude of the related amount (friction) related to the rotational resistance is estimated from the temperature information of the engine coolant, and the fuel amount at the restart after the idle stop is released is set. ing.
By the way, when the vehicle starts from cold and repeats running and stopping, the temperature of the lubricating oil in the transmission tends to be slower than the temperature of the engine coolant.

The temperature rise of the engine cooling water is the same regardless of whether there is an idle stop when the vehicle is stopped. However, in the transmission, there is a difference in the temperature rise of the lubricating oil depending on whether there is an idle stop when the vehicle is stopped. The temperature rise of the lubricating oil in the transmission tends to be slower when the idle stop is performed than when the idle stop is not performed when the vehicle is stopped.
In other words, when the vehicle starts from cold and repeats running and stopping, there is a difference in friction between the related amount related to engine rotational resistance (friction) and the related amount related to transmission rotational resistance (friction). However, the difference is further increased by performing idle stop.

  Therefore, only by estimating the relevant amount (friction) related to the rotational resistance of the engine without considering the relevant amount (friction) related to the rotational resistance of the transmission as in the idle stop vehicle described in Patent Document 1, When the transmission has not been warmed up, the engine torque amount is insufficient at the time of start-up after restarting after releasing the idle stop, and there is a possibility that start-up failure due to combustion failure and exhaust gas will deteriorate.

  As a solution to this problem, regardless of the amount of friction related to the rotational resistance of the transmission (friction), in any vehicle situation, to satisfy the engine torque required from engine restart to start-up, The amount of fuel at the time of restart is increased in advance.

As another solution, the target torque of the engine based on the temperature information of the engine coolant is used to ensure stable driving operability regardless of environmental temperature changes from the start to the completion of transmission warm-up. Based on the final target torque calculated by adding the transmission target torque and the basic target torque based on the temperature information of the transmission and the lubricating oil temperature of the transmission, the throttle opening is controlled to the open side so that it corresponds to the target intake air amount The engine torque amount is corrected by increasing the fuel amount via the intake air amount increase correction, or the ignition timing is controlled to advance based on the lubricating oil temperature of the transmission. A technique for correcting the above has been proposed (see, for example, Patent Document 2).

Another solution is to use a starter other than the gear mesh starter. Instead of the alternator assembled in the engine, a motor / generator is provided, and the power output from the motor / generator is transmitted to the engine crankshaft via the belt (belt transmission mechanism), and the meshing of the gears is performed. There is no starter.
In order to make up for the engine torque shortage by using the belt transmission mechanism of the starter, a technique for assisting until the engine rotation speed is stabilized has been proposed (for example, see Patent Document 3).

  The calculation method of the final target torque at the time of restart is calculated by calculating the four parameters of starting friction, basic target torque, engine friction (water temperature correction torque), and transmission friction (hydraulic oil temperature correction torque). It is calculated by adding.

JP 2005-42572 A JP 2007-332775 A JP 2001-304007 A

However, the idle stop vehicle described in Patent Document 2 has a problem in the method of calculating the final target torque in the restart after the idle stop release unique to the idle stop vehicle.
That is, a calculation error of several percent is conceivable for the calculation value of each parameter, and the calculation error increases by adding each parameter. As the parameter calculation error increases, the final target torque becomes overcorrected or undercorrected. In the case of overcorrection, drivability is adversely affected by increasing the engine speed at start-up and the vehicle's feeling of popping out when starting, and in the case of insufficient correction, engine stall due to start-up failure or slack at start-up occurs. There is a possibility of doing.

  Further, it is necessary to experimentally match in advance the four parameters of the starting friction, the basic target torque, the engine friction, and the transmission friction with an actual machine.

  In addition, the starter for an idle stop vehicle described in Patent Document 3 has a drawback that the system configuration is complicated and the cost is higher than that of a gear meshing starter.

  The present invention has been made to solve the above-mentioned problems, and suppresses excessive fuel consumption, suppresses start failure and start failure due to overcorrection or insufficient correction, and after the idle stop is released. It is an object of the present invention to provide an engine start control device in which an optimal fuel amount at start-up with respect to an engine torque amount according to a vehicle condition is controlled from engine restart to start.

An engine start control device for an idle stop vehicle according to the present invention is a start control device that controls a gear meshing type start device, and at the time of restart corresponding to the engine torque amount required from engine restart to start. Means for calculating the basic fuel amount of the engine, first related amount estimating means for estimating a first related amount related to the rotational resistance of the engine, and a second related amount for estimating the second related amount related to the rotational resistance of the transmission. Two related amount estimating means, means for determining the necessity of correction of the basic fuel amount based on the difference in the related amount between the first related amount and the second related amount, and correction required Means for calculating a fuel correction amount corresponding to the difference between the related amounts when determined, and setting the basic fuel amount corrected by the fuel correction amount as a fuel amount at restart, and determining that correction is unnecessary And And means for setting the basic fuel amount as the restart-time fuel amount, means for calculating a basic fuel amount at the time of the restart, a temperature of the cooling water of the engine determined experimentally in advance in actual The basic fuel amount is calculated by searching a map showing the relationship with the basic fuel amount at restart by the water temperature from the water temperature sensor .

  In the engine start control device for an idle stop vehicle according to the present invention, it is possible to determine whether or not the engine torque amount is corrected to the basic fuel amount at the time of restart, and from restart to start according to the difference in friction. By setting an optimal fuel amount that satisfies the engine torque amount required for the engine, it is possible to improve the startability of the engine, to suppress the start failure due to the combustion failure and the deterioration of the exhaust gas.

1 is a configuration diagram showing an engine started by an engine start control device according to an embodiment of the present invention and a structure around the engine. 1 is a circuit diagram showing a schematic configuration of an engine start control device according to an embodiment of the present invention. FIG. It is a figure which shows the calculation method of the final target torque of an engine. It is a temperature transition diagram of the temperature of the cooling water of the engine and the temperature of the lubricating oil of the transmission when traveling in a predetermined traveling pattern with or without idling stop. It is a block diagram which shows roughly the control at the time of the restart of the engine start control apparatus by embodiment of this invention. It is a map which shows the relationship between the temperature of engine cooling water, and the basic fuel amount at the time of restart. It is a map which shows the relationship between the temperature of engine cooling water, and the friction of an engine. It is a map which shows the relationship between the temperature of the lubricating oil of a transmission, and the friction of a transmission. It is a map which shows the fuel correction amount at the time of restart according to the difference of the friction of an engine and a transmission. It is a flowchart for demonstrating control at the time of restart of an engine starting control apparatus.

DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of an engine start control device of the present invention will be described with reference to the drawings.
Embodiment 1 FIG.
FIG. 1 is a configuration diagram showing an engine started by the engine start control device according to Embodiment 1 of the present invention and a structure around the engine.
The engine start control device according to Embodiment 1 of the present invention is mounted on a vehicle with an idle stop function (hereinafter referred to as an idle stop vehicle) that employs AT or CVT.
The traveling engine 1 mounted on the idle stop vehicle is, for example, a multi-cylinder reciprocating engine, for example, an electronically controlled fuel injection type gasoline engine. That is, in the engine 1, the piston housed in the cylinder reciprocates, so that a predetermined combustion cycle, for example, an intake stroke, a compression stroke, a combustion stroke, and an exhaust stroke is repeatedly performed, and the crankshaft 1a to which the piston is connected. To output power. The transmission 2 is connected to the crankshaft 1a of the engine 1, the traveling wheels are connected to the transmission 2, and the rotational power necessary for traveling is output to the traveling wheels.

A starter 4 as a starting device that is normally used is provided on the side of the rear side (output side) of the engine 1, and rotational power is transmitted from the starter 4 through a gear type transmission mechanism 3 such as a reduction gear type. 1 is transmitted.
A pinion gear is assembled to the output shaft of the starter motor 4a of the starter 4. On the other hand, a ring gear as a gear transmission mechanism 3 that can mesh with the pinion gear is provided on the outer peripheral portion of the flywheel at the rear end of the crankshaft 1a. That is, the starter 4 enters the ring gear of the engine 1 so as to mesh with it, and transmits the rotational power from the starter motor 4a to the flywheel so that the engine 1 can be started. After the engine is started, the pinion gear is detached from the ring gear.

The ECU 19 determines the temperature state of the cooling water of the engine 1 by inputting the output from the water temperature sensor 8 provided in the engine 1 to the ECU 19 (for example, a control unit having a microcomputer). Can do.
Further, by inputting the output from the oil temperature sensor 9 provided in the transmission 2 to the ECU 19, the ECU 19 can determine the temperature state of the lubricating oil in the transmission 2.

FIG. 2 is a diagram schematically showing the configuration of the start control device 18 for the engine 1 using the starter 4.
Next, the start control device 18 for the engine 1 will be described.
The starter motor 4a is connected to a power supply circuit 11 with a vehicle-mounted battery 10 interposed.
Further, a signal line 12 extending from the S terminal of the starter motor 4a is provided with a normally open relay 13 and an ignition relay 14 as an on / off portion for the starter.
The relay 13 includes, for example, an open / close terminal 13a, a solenoid-driven contact piece 13b that closes the open / close terminal 13a, and a solenoid 13c that moves the contact piece 13b.
The relay 14 includes an open / close terminal 14a, a solenoid-driven contact piece 14b that closes the open / close terminal 14a, and a solenoid 14c that moves the contact piece 14b.

  The S terminal of the starter motor 4 a is connected to one contact of the open / close terminal 13 a of the relay 13 through the signal line 12. The other contact of the open / close terminal 13 a of the relay 13 is connected to one contact of the open / close terminal 14 a of the relay 14 via the signal line 12. The other contact of the open / close terminal 14 a of the relay 14 is connected to the control power circuit 15 via the signal line 16.

One end of the solenoid 14c of the relay 14 is connected to an ignition switch 17 that is operated by an ignition key (not shown), and when the ignition key is operated to the start position, the ignition switch 17 is turned on and the relay 14 is closed. When the relay 14 is closed, the control voltage Vb is supplied to the relay 13.
When the ignition switch 17 is turned on and the relay 13 is closed, the control voltage Vb is input to the S terminal of the starter motor 4a, and the starter motor 4a is activated.
One end of the solenoid 13 c of the relay 13 is connected to the ECU 19, and the other end of the solenoid 13 c is connected to the control power circuit 15.

  The ECU 19 has an idle stop function for controlling the fuel injection system and the ignition system to stop the operation of the engine 1 when a predetermined stop condition is satisfied during vehicle travel. The predetermined stop condition is, for example, that the shift position sensor that detects the position of the shift lever of AT or CVT detects the D position, the vehicle speed sensor detects the vehicle speed of 0 km / h, and the brake sensor depresses the brake pedal. It is all satisfied to detect the rare state.

  Further, the ECU 19 has a restart function for restarting the engine 1 by the starter 4 when a predetermined restart condition is satisfied after the idle stop. The predetermined restart condition is, for example, that both the shift position sensor detects the D position and the brake sensor detects a signal indicating the return of the brake pedal are satisfied.

In this restart function, the optimum amount of fuel required when the engine 1 is restarted is determined according to the situation of the vehicle. That is, the amount of fuel required for starting the engine correlates with the magnitude of a related amount (hereinafter referred to as “friction”) related to the rotational resistance of the engine 1 and the transmission 2. That is, if the friction is small, the engine 1 and the transmission 2 require a small starting torque for restarting, and if the friction is large, the starting torque required for restarting must be large.
Further, when the friction of the engine 1 is small and the friction of the transmission 2 is large, the starting torque required for restarting becomes large. Therefore, the amount of fuel that satisfies the torque amount of the engine 1 required when the engine 1 is restarted is set according to the difference in friction.

FIG. 3 shows a conventional calculation method and a calculation method of the present invention in the method of calculating the final target torque of the engine 1 at the time of restart.
In the conventional calculation method, four parameters of starting friction, basic target torque, engine friction (water temperature correction torque), and transmission friction (hydraulic oil temperature correction torque) are calculated and the calculated values are added to calculate the engine. A final target torque of 1 is obtained.
In the calculation method of the present invention, the final target torque of the engine 1 is obtained by calculating two parameters, the basic fuel amount at restart and the fuel correction amount at restart, and adding the calculated values.

The basic fuel amount at the time of restart is a fuel amount that satisfies the torque amount of the engine 1 required at the time of restart, which is a combination of the friction at the start, the basic target torque, and the engine friction.
The restart fuel correction amount is a fuel amount that corrects a shortage of fuel according to the difference in friction when the transmission friction is larger than the engine friction.

A calculation error of about ± 1% can be considered for the calculation value of each parameter. Since the conventional calculation method adds four parameters, a calculation error of about ± 4% occurs.
On the other hand, in the calculation method of the present invention, since two parameters are added, the calculation error can be reduced to about ± 2%.

FIG. 4 shows the temperature transition of the cooling water temperature of the engine 1 and the lubricating oil temperature of the transmission 2 when a vehicle with or without the idle stop function is driven in a predetermined driving pattern.
For example, when the vehicle starts from the cold state and travels in a predetermined traveling pattern, the temperature of the lubricating oil in the transmission 2 tends to be slower than the temperature of the cooling water in the engine 1.
Further, the temperature rise of the cooling water of the engine 1 is the same regardless of the presence or absence of the idle stop, but the transmission 2 has a difference in the temperature rise tendency of the lubricating oil depending on the presence or absence of the idle stop.
The temperature rise of the lubricating oil in the transmission 2 tends to be slower when the idle stop is performed than when the idle stop is not performed when the vehicle is stopped. That is, when the vehicle starts from cold and repeats running and stopping, a difference in friction occurs between the friction of the engine 1 and the friction of the transmission 2, and the difference is further increased by performing idle stop. Is shown.

FIG. 5 is a block diagram schematically showing restart control in the engine start control device according to Embodiment 1 of the present invention.
In the engine start control device according to Embodiment 1 of the present invention, water temperature and oil temperature data input from the water temperature sensor 8 and the oil temperature sensor 9 according to the instructions of the program stored in the ROM by the computer included in the ECU 19 are stored. A map stored in the storage device is searched to extract necessary data.
In the storage device, the relationship between the temperature of the cooling water of the engine 1 and the basic fuel amount at restart shown as a map in FIG. 6, the temperature of the cooling water of the engine 1 shown as a map in FIG. The relationship between the friction, the temperature of the lubricating oil of the transmission 2 shown as a map in FIG. 8 and the friction of the transmission 2, and the difference between the friction of the engine 1 and the friction of the transmission 2 shown as a map in FIG. The relationship with the fuel correction amount at the time of restart is experimentally obtained and stored in advance by an actual machine.

  The restart basic fuel amount calculation means 20 in the ECU 19 obtains the water temperature from the water temperature sensor 8, retrieves a map of the relationship between the coolant temperature of the engine 1 and the restart basic fuel amount from the storage device, and obtained it. The map is searched using the water temperature as the cooling water temperature of the engine 1 to extract the corresponding basic fuel amount at restart.

  The engine friction estimation means 21 in the ECU 19 obtains the water temperature from the water temperature sensor 8, takes out a map of the relationship between the coolant temperature of the engine 1 and the friction of the engine 1 from the storage device, and uses the obtained water temperature of the engine 1. The map is searched using the temperature of the cooling water to extract the corresponding friction of the engine 1.

  The transmission friction estimation means 22 in the ECU 19 acquires the oil temperature from the oil temperature sensor 9, takes out a map of the relationship between the temperature of the lubricating oil of the transmission 2 and the friction of the transmission 2 from the storage device, and transmits the acquired oil temperature to the transmission. The map is searched using the temperature of the lubricating oil 2 and the friction of the transmission 2 is extracted.

  The engine / transmission friction comparing means 23 in the ECU 19 calculates the difference between the engine 1 friction extracted by the engine friction estimating means 21 and the transmission 2 friction extracted by the transmission friction estimating means 22.

  The restart fuel correction amount calculation means 24 according to the friction difference in the ECU 19 extracts a map of the relationship between the difference between the friction of the engine 1 and the friction of the transmission 2 and the restart fuel correction amount from the storage device. The map is searched using the friction difference calculated by the friction comparison means 23 as the friction difference, and the corresponding fuel correction amount at restart is extracted.

  The restart-time final fuel amount calculation means 25 in the ECU 19 adds the restart-time basic fuel amount extracted by the restart-time basic fuel amount calculation means 20 to the restart-time fuel correction amount calculation means 24. The final fuel amount at restart is calculated by adding the fuel correction amount at start.

FIG. 10 is a flowchart showing a procedure for restart control of the engine 1 that has been idle-stopped.
Next, control for restarting the engine 1 that has been idle-stopped will be described. The ECU 19 starts control to restart the engine 1 at a predetermined cycle.
In step S1, the ECU 19 determines whether a restart condition is established based on data detected by the vehicle speed sensor, the brake sensor, and the shift position sensor. If the ECU 19 determines that the restart condition is not satisfied, the ECU 19 proceeds to step S2. If the ECU 19 determines that the restart condition is satisfied, the ECU 19 proceeds to step S3.
In step S2, the ECU 19 continues the idle stop state and ends the restart control.

In step S3, the ECU 19 uses the temperature information of the cooling water for the engine 1 from the water temperature sensor 8 for the engine 1 to calculate the temperature of the cooling water for the engine 1 stored in the storage device and the basic fuel amount at restart. A map showing the relationship is searched, and the corresponding restart basic fuel amount is extracted.
Next, in step S <b> 4, the ECU 19 searches for a map showing the relationship between the coolant temperature of the engine 1 and the friction of the engine 1 using the temperature information of the coolant of the engine 1 from the water temperature sensor 8 of the engine 1. Then, the friction of the engine 1 is set as a related quantity (Feug) related to the rotational resistance of the engine 1.

Next, in step S <b> 5, the ECU 19 uses the temperature information of the lubricating oil of the transmission 2 from the oil temperature sensor 9 of the transmission 2 to create a map showing the relationship between the lubricating oil temperature of the transmission 2 and the friction of the transmission 2. By searching, the friction of the transmission 2 is set as a related quantity (Ftrans) related to the rotational resistance of the transmission 2.
Next, in step S6, the ECU 19 causes the related quantity (Ftrans) related to the rotational resistance of the transmission 2 obtained in step S4 to exceed the related quantity (Feng) related to the rotational resistance of the engine 1 obtained in step S3. If it exceeds, the process proceeds to step S7, and in the following case, the process proceeds to step S10.

In step S <b> 7, the ECU 19 subtracts the related amount (Feng) related to the rotational resistance of the engine 1 from the related amount (Ftrans) related to the rotational resistance of the transmission 2 to obtain the friction difference.
Next, in step S8, the ECU 19 searches the map indicating the relationship between the difference between the friction of the engine 1 and the friction of the transmission 2 stored in the storage device and the fuel correction amount at restart by the difference in friction. The corresponding fuel correction amount at restart is extracted.
Next, in step S9, the ECU 19 adds the restart fuel correction amount obtained in step S7 to the restart basic fuel amount obtained in step S8 to calculate the restart final fuel amount, and then proceeds to step S11. move on.
In step S10, the ECU 19 sets the restart basic fuel amount that can satisfy the engine torque amount necessary for the friction of the engine 1 as the restart final fuel amount, and proceeds to step S11.
In step S11, the ECU 19 turns on the relay 13, operates the starter 4, and restarts the engine 1 based on the final fuel amount at restart.

  The start control device for the engine 1 according to the first embodiment of the present invention calculates the optimal fuel amount at the start with respect to the torque amount of the engine 1 according to the situation of the vehicle. It is possible to improve startability and startability before starting.

  Further, this is a gear-meshing type starter with a simple system configuration. The friction of the engine 1 and the transmission 2 is estimated from the temperature information of the cooling water of the engine 1 and the temperature information of the lubricating oil of the transmission 2, and the estimated friction. By comparing the vehicle conditions, the vehicle's condition is judged, the amount of engine torque required from restart to start is estimated from the difference in friction obtained from the comparison results, and the optimal restart according to the difference in friction It is possible to set the amount of fuel at the time, and it is not necessary to set the amount of fuel at the time of restart in advance in order to ensure startability and startability as in the prior art. Can be suppressed.

  In addition, only when the friction of the transmission 2 is larger than the friction of the engine 1 to the basic fuel amount at restart that has been experimentally matched with the actual machine in advance according to the final target torque of the engine required at the time of restart, The fuel amount at the time of final restart is set by adding the restart fuel correction amount corresponding to the difference in friction to the fuel amount. In other words, since there are two parameters to be calculated at the time of restart, the basic fuel amount at restart and the fuel correction amount at restart that is added according to the difference between the frictions, the calculation error when adding the parameters is larger than the conventional one. There is provided a start control device that can reduce start-up failure and start-up failure due to overcorrection or insufficient correction.

  In addition, since the two parameters, which are experimentally obtained in advance with an actual machine, are the basic fuel amount at restart and the fuel correction amount at restart, the number of matching steps can be reduced.

  DESCRIPTION OF SYMBOLS 1 Engine, 1a Crankshaft, 2 Transmission, 3 Gear type transmission mechanism, 4 Starter, 4a Starter motor, 8 Water temperature sensor, 9 Oil temperature sensor, 10 Battery, 11 Power supply circuit, 12 Signal line, 13 Relay, 13a Open / close terminal, 13b contact piece, 13c solenoid, 14 relay, 14a open / close terminal, 14b contact piece, 14c solenoid, 15 control power circuit, 16 signal line, 17 ignition switch, 18 start control device, 19 ECU, 20 basic fuel amount at restart Calculation means, 21 engine friction estimation means, 22 transmission friction estimation means, 23 friction comparison means, 24 restart fuel correction amount calculation means, 25 restart final fuel amount calculation means.

Claims (1)

In a start control device for controlling a gear meshing start device,
Means for calculating a basic fuel amount at restart corresponding to the torque amount of the engine required from restarting the engine to starting;
First related amount estimating means for estimating a first related amount related to the rotational resistance of the engine;
Second related quantity estimating means for estimating a second related quantity related to the rotational resistance of the transmission;
Means for determining the necessity of correcting the basic fuel amount based on a difference in the related amount between the first related amount and the second related amount;
Means for calculating a fuel correction amount corresponding to the difference between the related amounts when it is determined that correction is necessary, and setting the basic fuel amount corrected by the fuel correction amount as a fuel amount at restart;
Means for setting the basic fuel amount as a restart fuel amount when it is determined that correction is unnecessary ,
The means for calculating the basic fuel amount at the time of restart is a map showing the relationship between the engine cooling water temperature and the restart basic fuel amount experimentally obtained in advance by an actual machine based on the water temperature from the water temperature sensor. An engine start control device for an idle stop vehicle characterized by searching and calculating the basic fuel amount .

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