JP5222122B2 - Engine start control device - Google Patents

Description

  The present invention relates to a start control device that starts an engine by operating a start button.

  In recent years, a push start system has been put into practical use in which a driver can start an internal combustion engine by simply pressing a predetermined start button without inserting a key into a key cylinder. This push start system performs a series of operations from cranking to engine start (complete explosion) by simply pressing a start button (so-called push switch) instead of the conventional ignition key. 1 (Japanese Patent Laid-Open No. 2003-83210) discloses a technique in which cranking is continued after the start button is pressed until the engine is determined to be complete explosion.

  By the way, in a diesel engine or the like that requires engine preheating at the time of starting, the time required for the engine to start (complete explosion) is long, and the engine preheating time also varies depending on the outside air temperature. Therefore, in this type of engine, at an extremely low temperature such as −20 [° C.] or less, the engine often does not start immediately (complete explosion) after cranking is completed.

  Even in such a situation where cold start is difficult, as disclosed in Patent Document 1 described above, if the operation of the starter motor is continued until the engine completes explosion, the cranking time becomes longer than necessary. It may cause the battery to run out.

Therefore, for example, in Patent Document 2 (Japanese Patent Application Laid-Open No. 2005-207263), when the start button is pressed once, cranking is started, and the engine starts (complete explosion) within a predetermined time (for example, 10 [sec]). If, at that time, cranking is stopped and the engine does not start (complete explosion) even after a predetermined period of time, such as at cryogenic start, cranking is stopped and the start button is pressed again. A technique for preventing restart is disclosed.
JP 2003-83210 A JP 2005-207263 A

  However, in the technique disclosed in Patent Document 2 described above, the cranking continuation time of one time is determined in advance, so that, for example, the engine shifts from the initial explosion to the continuous explosion state, and starts a little more (complete explosion). Even in such a situation, when a predetermined time has elapsed, the cranking is uniformly stopped. Therefore, there is a problem that reliable startability cannot be obtained as compared with the case where cranking is performed by manual control.

  Further, if the engine does not start when a predetermined time has elapsed, the cranking must be started again by operating the start button after the engine is temporarily stopped, which increases the battery consumption.

  In view of the above circumstances, the present invention makes it possible to obtain a good startability by extending the cranking continuation time when the engine is in the process of starting from the initial explosion to the complete explosion. To provide an engine start control device that can reduce the burden on the battery while notifying the driver that starting is difficult as the cranking continuation time within the set time when the explosion does not occur. Objective.

  In order to achieve the above object, an engine start control device according to the present invention includes a cranking start means for starting cranking of an engine when an operation of a start button is detected, and a cranking duration measuring means for measuring a cranking duration. A complete explosion detecting means for detecting a complete explosion of the engine, and the cranking continuation time measured by the cranking continuation time measuring means reaches a preset reference start time or within the reference start time Cranking stop means for stopping cranking when the engine is completely detonated, and starting process detecting means for detecting whether or not the engine is in the process of starting from the initial explosion to the complete explosion, the cranking stop The means extends the reference start time by a set time when the start-up detection means determines that the engine is under start-up. And characterized in that.

  According to the present invention, when the engine is in the process of starting from the first explosion to the complete explosion, the cranking continuation time is extended, so that cranking is continuously performed to obtain a good startability. Can do. Also, if the engine does not reach the first explosion, setting the cranking duration within the set time can inform the driver that starting is difficult and reduce the burden on the battery. Can do.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a system configuration diagram of the engine control apparatus. In the present embodiment, a diesel engine is described as an example of the engine. However, the present embodiment can be applied to a gasoline engine.

  A vehicle equipped with a diesel engine is provided with an engine control device (E / G_ECU) 1 and a push start control device (P / S_ECU) 11 as control devices for executing start control. The ECUs 1 and 11 are mainly composed of a microcomputer having a CPU, a ROM, a RAM, an input / output interface, etc. (not shown), and can communicate with each other through an in-vehicle communication line such as CAN (Controller Area Network) communication. It is connected to the.

  Connected to the input side of the E / G_ECU 1 are a crank angle sensor 2 for detecting the engine speed, fuel injection timing at the start, and the like from a rotation of the crankshaft, a voltage sensor 3 for detecting a battery voltage, and the like. A glow plug 4 and an injector 5 that preheat the combustion chamber at the start are connected to the output side of the E / G_ECU 1, and a starter motor 7 is connected via a starter relay 6. The glow plug 4 and the injector 5 are provided for each cylinder, and fuel is injected from each injector 5 at every predetermined crank angle timing.

  In addition, a push switch 12 as a start button is connected to the input side of the P / S_ECU 11. This push switch 12 is a constant contact open type switch whose contact is closed (ON) only when it is pressed.

  Further, the P / S_ECU 11 turns on the starter relay 6 when detecting that the push switch 12 is turned on by the driver after the ignition switch is turned on. Then, electric power is supplied to the starter motor 7 and engine cranking is started. At the same time, the cranking time is counted, and if the engine starts (complete explosion) within the set time, or if the set time has passed without complete explosion, the starter relay 6 is turned off and cranking is automatically performed. To stop.

  Specifically, the engine start control executed by the P / S_ECU 11 is processed in accordance with a start control routine shown in FIG. This routine is performed when a preset start permission condition (for example, the ON signal is output from the push switch 12 when the select lever is set to the P range and the brake pedal is depressed) is satisfied. Will be launched.

  In step S1, it is determined whether or not preheating by the glow plug 4 has been completed. Preheating in the combustion chamber by the glow plug 4 is controlled by the E / G_ECU 1. When the E / G_ECU 1 receives a start permission signal indicating that the start condition output from the P / S_ECU 11 has been satisfied, the E / G_ECU 1 energizes the glow plug 4 to generate heat and starts preheating. And when preheating is completed in a predetermined manner, a preheating completion signal is output to the P / S_ECU 11.

  In step S1, it waits until a preheating completion signal is output from P / S_ECU11, and when a preheating completion signal is received, it progresses to step S2. In step S2, the starter relay 6 is turned on. Then, the starter motor 7 is energized through the starter relay 6, and cranking is started by driving the starter motor 7. Therefore, the processing in this step corresponds to the cranking start means of the present invention.

  When cranking is started, a detection signal is output from the crank angle sensor 2, so the E / G_ECU 1 injects fuel from the injector 5 of the fuel injection target cylinder based on the signal from the crank angle sensor 2.

  Thereafter, the process proceeds to step S3, and the cranking continuation time tim is counted (tim ← tim + 1). This cranking continuation time tim is cleared when the starter relay 6 is switched from OFF to ON. Note that the processing in this step corresponds to the cranking duration measuring means of the present invention.

  Thereafter, when the process proceeds to step S4, the engine speed Ne calculated based on the detection signal from the crank angle sensor 2 is read by the E / G_ECU 1, and the engine speed Ne and a preset complete explosion determination speed Nest are set. Compare. The processing in this step corresponds to the complete explosion detection means of the present invention.

  The complete explosion determination rotation speed Nest is a rotation speed that starts to rotate autonomously even when the starter motor 7 is stopped, and is set in advance based on experiments or the like. Incidentally, in this embodiment, although set to about 600 [rpm], it differs for every engine to employ. Further, the complete explosion determination rotational speed Nest may be variably set based on the engine temperature. When the engine is completely detonated, the engine speed Ne increases momentarily to a value higher than the target idle speed in order to prevent engine stall, but thereafter, the engine speed Ne converges to the target idle speed by feedback control. Is done.

  If it is determined in step S4 that Ne ≧ Nest complete explosion, the routine jumps to step S10. If Ne <Nest has not yet reached the complete explosion, the process proceeds to step S5 to check whether the engine is in the process of starting. The processing in step S5 corresponds to the starting process detecting means of the present invention.

  Whether or not the engine is in the process of starting is determined by the engine speed Ne, the engine speed Ne (the engine speed Ne calculated during the current routine execution), and the engine speed Ne (n-1) calculated during the previous calculation execution. Is determined on the basis of the difference between the engine speeds Ne. For example, the engine rotation speed Ne is higher than the cranking rotation speed (rotation speed for driving the engine) by the starter motor 7 and lower than the complete explosion determination rotation speed Nest, and the fluctuation of the engine rotation speed Ne is set in advance. When it is larger than the fluctuation range, it is determined that the vehicle is starting. Alternatively, when each cylinder is provided with an in-cylinder pressure sensor, when the in-cylinder combustion state is detected by the increase in the in-cylinder pressure, and the engine speed Ne has not reached the complete explosion determination speed Nest, judge. When determining whether or not the engine is in the process of starting from the fluctuation of the engine speed Ne, the crank angle sensor 2 serves as a combustion state detection means. Further, when the in-cylinder combustion state is detected by the in-cylinder pressure sensor, this in-cylinder pressure sensor becomes the combustion state detection means.

  More specifically, for example, when the crank angle sensor 2 is used as the combustion state detecting means, the engine rotation Ne during the expansion stroke increases when the combustion cylinder ignites, and decreases when the misfire occurs. Therefore, when the increase in the engine gin rotation speed Ne during the expansion stroke is larger than a predetermined value, it is determined that the combustion is performed, and when it is less than that, it is determined that the misfire is generated.

  Further, in an engine provided with an in-cylinder pressure sensor in each cylinder, the combustion state of each cylinder can be directly detected from fluctuations in the in-cylinder pressure. In this case, an average value or a peak value of the in-cylinder pressure in the expansion stroke of each cylinder is detected, and when this value is larger than a predetermined value, it is determined as combustion, and when it is less than that, it is determined as misfire.

  Then, the combustion state of each cylinder is detected for each predetermined combustion cycle, and when the ratio of the number determined to be combustion within the preset number of cycles is within the set range, it is determined that the engine is starting. The process for detecting the combustion state for each combustion cycle corresponds to the cycle-by-cycle combustion detection means of the present invention. Alternatively, the combustion state of each cylinder is detected for each cylinder, and when it is determined that more than the set number of cylinders in all the cylinders is in combustion, it is determined that the engine is starting. The process for detecting the combustion state for each cylinder corresponds to the cylinder-by-cylinder combustion detection means of the present invention.

  If it is determined in step S5 that the engine is not in the process of starting, the process proceeds to step S6. If it is determined that the engine is in the process of starting, the process branches to step S7.

  In step S6, the cranking continuation time tim is compared with a preset reference start time To. The reference start time To is a time that can be sufficiently explosive in a normal cranking operation, and is set to about 10 [sec] in the present embodiment.

  When the cranking continuation time tim has not reached the reference start time To (tim <To), the process returns to step S3, and the routine can be repeatedly executed. If the engine speed Ne does not reach the start-up state even when the cranking continuation time tim reaches the reference start time To (tim ≧ To), the process proceeds to step S10.

  When the process proceeds from step S4 or step S6 to step S10, the starter relay 6 is turned off and the routine is terminated. When the starter relay 6 is turned off, the energization to the starter motor 7 is cut off, so that engine cranking is stopped. Therefore, in this case, restart is not performed until the push switch 12 is turned on again in a state where the above-described start permission condition is satisfied. Note that the processing in steps S6, S8, and S10 corresponds to the cranking stop means of the present invention.

  On the other hand, if it is determined in step S5 that the engine is in the process of starting and the process proceeds to step S7, the battery voltage VB detected by the voltage sensor 3 is read, and the battery voltage VB is compared with a preset voltage determination value VBO. This voltage determination value VBO is a value set to prevent the battery from running out during cranking, and is set in advance based on experiments or the like.

  If the battery voltage VB ≧ VBO has a margin, the process proceeds to step S8. If the battery voltage VB <VBO has no margin, the process returns to step S6. Returning to step S6, the cranking continuation time tim and the reference start time To are compared. For example, as described later, if the reference start time To is extended by the extension time α, tim ≧ To Therefore, the process proceeds to step S10, the energization to the starter motor 7 is cut off, and the engine is stopped.

  On the other hand, when the process proceeds to step S8, the cranking continuation time tim is compared with the value obtained by adding the extension time α to the reference start time To (in this case, (To + α) becomes the reference start time). If tim <To + α, the process proceeds to step S9. When tim ≧ To + α, the engine does not completely explode even if the reference start time To is extended by the extension time α. Therefore, the process proceeds to step S10, the starter relay 6 is turned off, and the starter motor 7 is turned off. Stop the engine.

  This extended time α is extended, for example, even when the engine is shifted from the first explosion to the continuous explosion state and the situation where the explosion is likely to be completed in a short time exceeds the reference start time To. Thus, when it is possible to complete the explosion, it is a time for continuing the cranking, and is set in advance in search of actual rights. In this embodiment, the extension time α is set to about 2 to 5 [sec].

  Then, when the process proceeds to step S9, a starting command signal is output to the E / G_ECU 1, and the process returns to step S3.

  When the vehicle is completely stopped while the engine is rotating autonomously, when the push switch is pressed, an engine stop signal is output from the P / S_ECU 11 to the E / G_ECU 1, and the E / G_ECU 1 A fuel cut (in a gasoline engine, fuel cut and ignition cut) is performed and the engine is stopped.

  Next, the engine starting process executed by the E / G_ECU 1 will be described according to the engine starting process routine shown in FIG.

  In this routine, in step S11, it is checked whether or not a starting command signal from the P / S_ECU 11 is received. If a starting command signal is received, the process proceeds to step S12, and the starting command signal is received. If not, the routine is exited. Therefore, for example, when the starting command signal is output from the P / S_ECU 11 and then the starting command signal is interrupted, the routine exits from step S11, so that the E / G_ECU 1 performs idle control and warming. Normal fuel injection control including machine control is executed.

  Further, when the process proceeds to step S12, engine control is executed during starting and the routine is exited. In this starting engine control, the fuel injection timing from the injector 5, the fuel injection amount, and the energization current value to the glow plug 4 are set to optimum values corresponding to the combustion of the air-fuel mixture during starting.

  The optimum value is that during combustion, combustion has already occurred in each cylinder, so it can be estimated that the temperature in the combustion chamber of each cylinder has risen. If the control is performed, the fuel becomes excessive, and the startability may be deteriorated. Therefore, during the start-up, the fuel injection timing in the fuel injection control is set slower (retarded) than that set at the normal start-up, and the number of fuel injections in the multistage injection, and at the start-up The fuel injection amount increased by the increase is decreased. Further, during the start of starting, the exhaust emission can be reduced and the fuel consumption can be improved by reducing the number of fuel injections and the fuel injection amount. As a result, since this starting process is started immediately after the cranking is started, the optimum fuel control is practically performed immediately after the cranking is started.

  In this embodiment, the advance amount of the fuel injection timing, the number of reductions in the number of fuel injections in multi-stage injection, and the amount of reduction in the fuel injection amount are fixed values, but the engine operation such as the engine speed, the cooling water temperature, etc. You may make it vary based on the parameter which detects a state. In this case, the fuel injection timing, the number of fuel injections, and the fuel injection amount during the start-up are obtained in advance from experiments based on the above-described engine operation state parameters, and are stored in the storage unit of the E / G_ECU 1 in a map format. Further, the fuel injection timing, the number of fuel injections, and the fuel injection amount at the start climbing may be calculated by using an approximate expression obtained in advance from an experiment or the like based on a parameter for detecting the engine operating state.

  Thus, according to the present embodiment, when the engine at the time of cranking is in the process of starting, the cranking continuation time tim is substantially increased by the extension time α, so that it is difficult to start within the reference start time To. Good startability can be obtained even at a very low temperature.

  In addition, if the engine does not reach the starting stage within the cranking continuation time tim, the cranking is stopped when the cranking continuation time tim elapses, so that it is notified to the driver that starting is difficult. In addition, the burden on the battery can be reduced by stopping the cranking. Similarly, when the cranking continuation time tim is extended by the extension time α, if the battery voltage VB is low, the cranking continuation time tim is not extended, so the burden on the battery is reduced and the battery can be restarted satisfactorily. it can.

System configuration diagram of engine control device Flow chart showing start control routine Flowchart showing an engine starting process routine

Explanation of symbols

1 ... Engine control device,
3 ... Voltage sensor,
4 ... Glow plug,
5 ... Injector,
6 ... Starter relay,
7 ... Starter motor,
11 push start control device,
12 ... push switch,
α ... extension time,
Ne ... engine speed,
Nest ... Complete explosion determination rotation speed,
To ... Reference start time,
VB ... battery voltage,
VBO: Voltage judgment value,
tim ... Cranking duration

Claims (10)

Cranking start means for starting cranking of the engine when the operation of the start button is detected;
A cranking duration measuring means for measuring the cranking duration;
A complete explosion detection means for detecting the complete explosion of the engine;
Cranking stop means for stopping cranking when the cranking continuation time measured by the cranking continuation time measuring means reaches a preset reference start time or when the engine has completely exploded within the reference start time. When,
Starting start detecting means for detecting whether or not the engine is in the starting start from the first explosion to the complete explosion,
The engine start control device, wherein the cranking stop means extends the reference start time by a set time when the start-up detecting means determines that the engine is in the start-up. 2. The engine start control device according to claim 1, wherein when the reference start time is extended, at least a fuel injection amount and a fuel injection timing in the fuel injection control are changed. 2. The engine start control device according to claim 1, wherein the cranking stop means prohibits the extension of the reference start time when the battery voltage is equal to or lower than a preset voltage determination value. 2. The engine start control device according to claim 1, wherein the starting process detecting means determines whether or not the engine is in the process of starting based on fluctuations in engine speed during cranking. Combustion state detection means for detecting the combustion state in each cylinder;
A cycle-by-cycle combustion detection means for detecting, for each combustion cycle, whether or not each cylinder is in a combustion state based on the in-cylinder combustion state of each cylinder detected by the combustion state detection means;
2. The start-up detecting means determines that the engine is in the process of starting when the ratio of the number determined to be combusted within the number of cycles set in advance by the cycle-by-cycle combustion detecting means is within a set range. Engine start control device. Combustion state detection means for detecting the combustion state in each cylinder;
A cylinder-by-cylinder combustion detection unit that detects whether the cylinder is in a combustion state based on the combustion state in the cylinder detected by the combustion state detection unit;
2. The engine start control device according to claim 1, wherein the starting process detecting unit determines that the engine is starting when the cylinder-specific combustion detecting unit determines that more than a set number of cylinders in all cylinders is in combustion. . The combustion state detection means is a crank angle sensor that detects an engine speed at a predetermined crank angle,
6. The engine start control device according to claim 5, wherein the cycle-by-cycle combustion detection means determines that combustion occurs when the increase in the engine speed during the expansion stroke is greater than a predetermined value. The combustion state detection means is a crank angle sensor that detects an engine speed at a predetermined crank angle,
7. The engine start control device according to claim 6, wherein the cylinder-by-cylinder combustion detection means determines that combustion occurs when the increase in the engine speed during the expansion stroke is greater than a predetermined value. The combustion state detecting means is an in-cylinder pressure sensor that detects an in-cylinder pressure of each cylinder,
6. The engine start control device according to claim 5, wherein the cycle-by-cycle combustion detection means determines that combustion occurs when the increase in the in-cylinder pressure during the expansion stroke is greater than a predetermined value. The combustion state detecting means is an in-cylinder pressure sensor that detects an in-cylinder pressure of each cylinder,
7. The engine start control device according to claim 6, wherein the cylinder-by-cylinder combustion detection means determines that combustion occurs when an increase in the in-cylinder pressure during an expansion stroke is greater than a predetermined value.

Images