ENGINE CONTROL DEVICE

Abstract

Motor control device (1), comprising: an electronically controlled throttle (11) configured to control the flow rate of an air-fuel mixture flowing into a cylinder (3) of an engine (2) by electronically controlling a throttle opening angle, a fuel injection device (13) configured to inject fuel into air supplied to the cylinder (3), an ignition device (12) configured to ignite an air-fuel mixture present in the cylinder (3), and an engine control unit (21) configured to perform an ignition timing / throttle opening angle change process to control the ignition device (12) and the electronically controlled throttle (11) while the operation of a body driven by the engine (2) is in a steady state, such that the ignition time of an air-fuel mixture present in the cylinder (3) is advanced and the throttle opening angle is reduced while maintaining a constant torque of the engine (2), wherein the engine control unit (21) is configured to perform a fuel cut-off control process in which a supply of fuel to the fuel injection device (13) is suspended when the throttle opening angle has become very small, and wherein the engine control unit (21) is configured in the ignition timing / throttle opening angle change process to control the electronically controlled throttle (11) such that the throttle opening angle does not become less than or equal to a throttle opening angle limit at which the fuel cut-off control process is initiated.

Description

[0001] The present invention relates to an engine control device for controlling engine ignition timing and throttle opening angle. The fuel efficiency of a vehicle can be increased by advancing the engine ignition timing while the vehicle is moving. JP H10-115275 A discloses an ignition timing control device that advances the ignition timing depending on which of the prescribed speed ranges the current speed of the vehicle is in when a prescribed high-speed traveling condition is met.

[0002] DE 10 2013 111 446 A1 describes an engine control device specifically configured for purging condensate from a charge air cooler (CAC) to an engine intake in order to reduce engine misfiring or knocking due to water ingestion. To this end, the engine control device temporarily adjusts the ignition timing and, if necessary, the throttle valve opening angle. To keep engine torque constant during this condensate purge, a first routine advances the ignition timing depending on ambient humidity and the condensate level in the CAC. In another routine, referred to as the "proactive CAC purge routine," the ignition timing is initially retarded and the throttle valve opening is simultaneously increased at the start of the CAC purge procedure in order to keep engine torque constant.Upon completion of this emptying procedure, all parameters are returned to their previous or currently requested settings.

[0003] DE 10 2012 217 548 A1 discloses an engine control device in which, when a vehicle enters a steady cruise state in which hardly any acceleration or deceleration occurs, an advance angle target amount for each of a plurality of cylinders is gradually changed while, at the same time, the fuel injection amount is gradually reduced.

[0004] DE 10 2014 216 128 A1 discloses an engine control device in which, specifically for a phase of a transmission shift in a hybrid vehicle, the ignition timing is advanced relative to the MBT during an initial portion of a transmission upshift to accelerate torque reduction. Once the engine speed has been sufficiently reduced and is within a threshold range of the desired engine speed, the ignition timing can be retarded until the transmission shift is completed.

[0005] For example, while a vehicle is in a moving state, it is desirable to further advance the engine ignition timing to further increase fuel efficiency. However, if the ignition timing approaches an MBT ("minimum advance for the best torque"), engine torque is increased by advancing the ignition timing. This may impair vehicle maneuverability (e.g., the vehicle accelerates even though the driver keeps the accelerator pedal in the same position, which may cause driver discomfort).

[0006] The present invention has been made in view of the above problem, and an object of the invention is to provide an engine control device which enables further advancement of the engine ignition timing without deteriorating the maneuverability of a driven body such as a vehicle.

[0007] An engine control device of the invention has the features of claim 1.

[0008] The invention makes it possible to further advance the engine ignition timing without impairing the maneuverability of a body to be driven, such as a vehicle. Fig. 1 is a diagram illustrating an engine control device according to an embodiment of the present invention together with an engine. Fig. 2 is a flowchart of an engine control process executed by the engine control device according to the embodiment. Fig. 3 is a flowchart of an ignition timing / throttle opening angle changing process executed by the engine control device according to the embodiment. Fig. 4 is a flowchart of a change control process executed by the engine control device according to the embodiment.

[0009] An engine control device according to the present invention is equipped with an electronically controlled throttle that controls the flow rate of an air-fuel mixture flowing into a cylinder of an engine by electronically controlling a throttle opening angle, an ignition device that ignites an air-fuel mixture present in the cylinder, and an engine control unit that performs an ignition timing / throttle opening angle changing process while the operation of a body to be driven by the engine (e.g., a vehicle) is in a steady state. The ignition timing / throttle opening angle changing process is a process for controlling the ignition device and the electronically controlled throttle so that the timing of ignition of an air-fuel mixture present in the cylinder is advanced and the throttle opening angle is reduced while maintaining the engine torque constant.

[0010] In the ignition timing / throttle opening angle changing process, the engine control unit advances the ignition timing while decreasing the throttle opening angle to reduce the flow rate of an air-fuel mixture flowing into the cylinder. Decreasing the throttle opening angle serves to reduce engine torque by the same amount as advancing the ignition timing serves to increase engine torque, thereby keeping the engine torque constant. Since an increase in engine torque is prevented in this way even though the ignition timing is advanced, a phenomenon can be prevented in which a body to be driven by the engine is accelerated even though the driver keeps the accelerator pedal at the same position.As a result, the engine ignition timing is further advanced without impairing the maneuverability of a body to be driven by the engine, and fuel efficiency is thereby further increased.

[0011] Fig. 1 shows an engine control device 1 according to an embodiment of the invention together with an engine 2. The engine 2 and the engine control device 1, which in Fig. 1 are installed in a vehicle, such as a motorcycle. The engine control device 1 has a function of controlling the ignition timing of the engine 2 and the throttle opening angle according to the running state of the vehicle.

[0012] The engine control device 1 is equipped with an electronically controlled throttle 11, an ignition device 12, a fuel injection device 13, a crank angle sensor 15 as an engine rotation detecting unit, a throttle position sensor (TPS) 16 as a throttle opening angle detecting unit, an accelerator position sensor (APS) 17 as an accelerator position detecting unit, a gear position sensor 18, and an engine control unit (ECU) 21.

[0013] The electronically controlled throttle 11 is a device for controlling the flow rate of an air-fuel mixture flowing into the engine 2 by electronically controlling the throttle opening angle. The electronically controlled throttle 11 can change the throttle opening angle, that is, the opening angle of a throttle valve provided at a midway position in an air intake passage leading to an intake port of the engine 2, by controlling an engine according to a control signal C. th , which is output from the engine control unit 21.

[0014] The ignition device 12 is a device for igniting the air-fuel mixture present in a cylinder 3. Although Fig. 1 is simplified in that only a spark plug is shown as the ignition device 12, the ignition device 12 comprises known components for igniting an air-fuel mixture by generating an electric spark, such as the spark plug and an ignition coil. The ignition timing of the ignition device 12 is controlled by a control signal C ig controlled by the engine control unit 21.

[0015] The fuel injector 13 is a device for injecting fuel into air supplied to the cylinder 3. The fuel injection rate, fuel injection time, etc. of the fuel injector 13 are controlled by a control signal C f controlled by the engine control unit 21.

[0016] The crank angle sensor 15 is a device for detecting a rotational speed of the engine 2 (engine rotational speed). The crank angle sensor 15 outputs a detection signal D ne corresponding to an engine rotation speed to the engine control unit 21.

[0017] The throttle position sensor 16 is a device for detecting a throttle opening angle of the electronically controlled throttle 11. The throttle position sensor 16 outputs a detection signal D th , which indicates a throttle opening angle, to the engine control unit 21.

[0018] An accelerator position sensor 17 is a device for detecting an accelerator position. The accelerator position sensor 17 is attached, for example, to an accelerator grip of the motorcycle. The accelerator position sensor 17 outputs a detection signal D a, which indicates an accelerator position corresponding to, for example, an operation amount of the accelerator handle, to the motor control unit 21.

[0019] The gear position sensor 18 is a device for detecting a gear position of a transmission (not shown) provided in the vehicle. The gear position sensor 18 outputs a detection signal D g indicating a gear position to the engine control unit 21.

[0020] The engine control unit 21 is equipped with a central processing unit (CPU) 22 and a storage unit 23, including, for example, a non-volatile memory device. The engine control unit 21 can determine an engine rotation speed based on the detection signal D ne detect which is output from the crank angle sensor 15, and a throttle opening angle based on the detection signal D thoutput from the throttle position sensor 16. The engine control unit 21 can also detect an accelerator position based on the detection signal D a detect the signal output from the accelerator position sensor 17 and a gear position based on the detection signal D g detect which is output by the gear position sensor 18.

[0021] The engine control unit 21 can control the throttle opening angle and the ignition timing by the control signals C th and C ig are output to the electronically controlled throttle 11 and the ignition device 12, respectively. The engine control unit 21 can also control the fuel injection rate, the fuel injection timing, a fuel injection delay (injection cut-off), etc., by the control signal C f is output to the fuel injector 13.

[0022] The engine control unit 21 also executes an ordinary throttle opening angle control process, an ordinary ignition timing control process, a fuel cut control process, and an ignition timing / throttle opening angle changing process.

[0023] The conventional throttle opening angle control process is a process for controlling the throttle opening angle according to the engine speed and the accelerator position. The conventional throttle opening angle control process allows you to adjust how the throttle opening angle should be changed according to the engine speed and a change in the accelerator position. This allows you to improve the vehicle's maneuverability.

[0024] Specifically, in the ordinary throttle opening angle control process, the engine control unit 21 determines a throttle opening angle based on an engine rotational speed detected by the crank angle sensor 15 and an accelerator position detected by the accelerator position sensor 17 by referring to an ordinary throttle opening angle map 31. The engine control unit 21 controls the electronically controlled throttle 11 so that the actual throttle opening angle of the electronically controlled throttle 11 becomes equal to the thus determined throttle opening angle. The ordinary throttle opening angle map 31 is a three-dimensional map indicating a relationship between the engine rotational speed, the accelerator position, and the throttle opening angle, and is stored in the storage unit 23.

[0025] On the other hand, the conventional ignition timing control process is a process for advancing or retarding the ignition timing based on the engine rotation speed and the throttle opening angle. For example, the conventional ignition timing control process can increase fuel efficiency by advancing the ignition timing in a range where the engine rotation speed is high and the throttle opening angle is small. The conventional ignition timing control process can also suppress knocking by retarding the ignition timing when the throttle opening angle is large.

[0026] Specifically, in the ordinary ignition timing control process, the engine control unit 21 determines an ignition timing based on an engine rotation speed detected by the crank angle sensor 15 and a throttle opening angle detected by the throttle position sensor 16 by referring to an ordinary ignition timing map 32. The engine control unit 21 controls the ignition device 12 to ignite an air-fuel mixture at the thus determined ignition timing. The ordinary ignition timing map 32 is a three-dimensional map indicating a relationship between the engine rotation speed, the throttle opening angle, and the ignition timing, and is stored in the storage unit 23.

[0027] In the above-described embodiment, a throttle opening angle to be used for determining ignition timing in the ordinary ignition timing control process is detected by the throttle position sensor 16. Alternatively, a throttle opening angle to be used for determining ignition timing in the ordinary ignition timing control process may be determined based on an engine rotation speed detected by the crank angle sensor 15, an accelerator position detected by the accelerator position sensor 17, and the ordinary throttle opening angle map 31.

[0028] The fuel cutoff control process is a process for suspending the supply of fuel to the fuel injector 13 when the throttle opening angle has become very small and the misfire rate of the engine 2 has become large. The fuel cutoff control process can prevent a phenomenon that unburned gas flows to a catalyst unit of the exhaust system due to misfire and damages the catalyst.

[0029] Specifically, in the fuel cutoff control process, the engine control unit 21 compares a throttle opening angle detected by the throttle position sensor 16 with a throttle opening angle threshold value. If the detected throttle opening angle is less than or equal to the throttle opening angle threshold value, the engine control unit 21 performs control to suspend fuel injection from the fuel injector 13. The throttle opening angle threshold value is a throttle opening angle threshold value for judging whether fuel injection is postponed by the fuel cutoff control process and is stored in the storage unit 23.

[0030] The ignition timing / throttle angle change process is a process for further advancing the ignition timing from a point determined by the ordinary ignition timing control process and further decreasing the throttle opening angle from an angle determined by the ordinary throttle opening angle control process. The ignition timing / throttle angle change process can also achieve an increase in fuel efficiency. The ignition timing / throttle angle change process is described in detail below.

[0031] The engine control unit 21 executes various types of processes for controlling the driving of the engine 2 and the traveling of the vehicle along with the processes described above. For example, the engine control unit 21 executes an idle control process for controlling the idling of the engine 2.

[0032] Fig. Figure 2 shows the details of an engine control process executed by the engine control device 1. While the engine 2 is operating, the engine control device 1 executes the Fig. 2. In the engine control process, the engine control unit 21 judges in step S1 whether the vehicle is traveling at a constant speed, that is, whether it is in a running state. If the vehicle is not in a running state, the engine control unit 21 executes the above-described ordinary throttle opening angle control process, the ordinary ignition timing control process, and the fuel cut control process in parallel in step S2. On the other hand, if the vehicle is in a running state, the engine control unit 21 executes the above-described ignition timing / throttle opening angle changing process and the fuel cut control process in parallel in step S3.

[0033] The engine control unit 21 assesses in the Fig. 2, that the vehicle is in a running state if, for example, all of the following conditions (1) to (5) are met. (1) The motor rotation speed is approximately constant (e.g., the change of motor rotation speed in 0.1 seconds is within a range of -150 rpm to +150 rpm). (2) The throttle opening angle is larger than a specified value (e.g. 2%). (3) The accelerator position is approximately constant (e.g., the change of the accelerator position in 0.1 seconds is within a range of -5% to +5%). (4) The gear position is not in neutral. (5) No idle control is performed.

[0034] The engine control unit 21 judges whether the above conditions are met based on the detection signal D ne , which is output from the crank angle sensor 15, of the detection signal Dth output from the throttle position sensor 16, the detection signal D a , which is output from the accelerator position sensor 17, of the detection signal D g output from the gear position sensor 18, a flag indicating whether idle control is being performed (ie, a flag generated by the engine control unit 21 in the idle control process), and other information.

[0035] Fig. 3 shows the details of the ignition timing / throttle opening angle change process used in the Fig. 2 is executed. In the ignition timing / throttle opening angle changing process, first, in step S11, the engine control unit 21 determines a reduced throttle opening angle F th based on an engine speed detection value P ne, which is detected by the crank angle sensor 15 at a start of the ignition timing / throttle opening angle change process, and an accelerator position detection value P a , which is detected by the accelerator position sensor 17 at the start of the ignition timing / throttle opening angle change process by referring to a reduced throttle opening angle map 33 (described below). The reduced throttle opening angle F th is a final target throttle opening angle used when further decreasing the throttle opening angle from an angle determined by the ordinary throttle opening angle control process.

[0036] In step S12, the engine control unit 21 detects a throttle opening angle detection value P th at the start of the ignition timing / throttle opening angle change process based on the engine speed detection value P neat the start of the ignition timing / throttle opening angle change process and the accelerator position detection value P a at the start of the ignition timing / throttle opening angle change process by referring to the ordinary throttle opening angle map 31. The engine control unit 21 determines an advanced ignition timing F ig based on the motor rotation speed detection value P ne at the start of the ignition timing / throttle opening angle change process and the throttle opening angle detection value P th at the start of the ignition timing / throttle opening angle change process by referring to an advanced ignition timing map 34 (described below). The advanced ignition timing F igis a final target ignition timing used when the ignition timing advances further from a timing determined by the ordinary ignition timing control process.

[0037] In step S13, the engine control unit 21 executes a change control process for gradually reducing the throttle opening angle from the throttle opening angle at the start of the ignition timing / throttle opening angle change process to the reduced throttle opening angle F th and to gradually advance the ignition timing to the advanced ignition timing F ig from a point in time at the start of the ignition timing / throttle opening angle change process.

[0038] The reduced throttle opening angle map 33 is a three-dimensional map indicating a relationship between the engine rotation speed, the accelerator position, and the reduced throttle opening angle, and is stored in the storage unit 23. The advanced ignition timing map 34 is a three-dimensional map indicating a relationship between the engine rotation speed, the throttle opening angle, and the advanced ignition timing, and is stored in the storage unit 23. The reduced throttle opening angle map 33 and the advanced ignition timing map 34 are specific examples of the "target ignition timing / throttle opening angle information."

[0039] The reduced throttle opening angle map 33 and the advanced ignition timing map 34 are described in further detail below. For the sake of simplicity, the two formulations "torque before a change to a reduced throttle opening angle and advanced ignition timing" and "torque after a change to a reduced throttle opening angle and advanced ignition timing" are defined below. The "torque before a change to a reduced throttle opening angle and advanced ignition timing" is a torque of the engine 2 obtained when the actual throttle opening angle is set to a throttle opening angle detection value P th which is set based on a motor rotation speed detection value P ne , which is detected at a certain time while the vehicle is running, an accelerator position detection value P a, which is detected at the same time, and the ordinary throttle opening angle map 31, and the actual ignition timing is set to an ignition timing detection value P ig which is based on the engine rotation speed detection value P detected at the same time ne , the throttle opening angle detection value P detected at the same time th and the usual ignition timing map 32.

[0040] The “torque after change to a reduced throttle opening angle and an advanced ignition timing” is a torque of the engine 2 obtained when the actual throttle opening angle is changed to a reduced throttle opening angle F th which is set based on a motor rotation speed detection value P ne, which is detected at a certain time while the vehicle is running, an accelerator position detection value P detected at the same time a , and the reduced throttle opening angle map 33 is detected, and the actual ignition timing is set to an advanced ignition timing F ig which is based on the motor rotation speed detection value P detected at the same time ne , the throttle opening angle detection value P detected at the same time th and the advanced ignition timing map 34.

[0041] The reduced throttle opening angle map 33 and the advanced ignition timing map 34 are configured so that a "torque after changing to a reduced throttle opening angle and an advanced ignition timing" obtained at any time while the vehicle is running is always equal to a "torque before changing to a reduced throttle opening angle and an advanced ignition timing" obtained at the same time. Accordingly, the torque of the engine 2 remains the same even if the actual throttle opening angle and the actual ignition timing are each at a reduced throttle opening angle F. th and an advanced ignition timing F ig be changed by the ignition timing / throttle opening angle changing process at any time while the vehicle is running.

[0042] For example, the reduced throttle opening angle map 33 and the advanced ignition timing map 34 are formed as follows. First, the vehicle is placed in a running state. Then, the engine speed and accelerator position are set to specific values, and at this time, a "torque before changing to a reduced throttle opening angle and advanced ignition timing" is measured. Then, the ignition timing advances by a prescribed time while the engine speed and accelerator position remain as they are.After that, the throttle opening angle is decreased until the torque of engine 2 becomes equal to the "torque before changing to a decreased throttle opening angle and advanced ignition timing," while the engine rotation speed and accelerator position remain as they are, and the ignition timing remains equal to the advanced timing. When the torque of engine 2 becomes equal to the "torque before changing to a decreased throttle opening angle and advanced ignition timing," the engine rotation speed and accelerator position at that time are recorded, the ignition timing at that time is recorded as advanced ignition timing, and the throttle opening angle at that time is recorded as a decreased throttle opening angle.

[0043] The above set of operations is performed for substantially all combinations of engine rotational speed and accelerator position expected while the vehicle is in a running state. A corresponding relationship thus recorded between the engine rotational speed, accelerator position, and reduced throttle opening angle is converted into data in the form of a three-dimensional map (i.e., a reduced throttle opening angle map 33).

[0044] In addition, throttle opening angles corresponding to the respective accelerator positions recorded by the above set of operations are determined using the ordinary throttle opening angle map 31, and a corresponding relationship between the thus-determined throttle opening angle, the thus-recorded engine rotational speed, and the thus-recorded advanced ignition timing are converted into data in the form of a three-dimensional map, ie, an advanced ignition timing map 34.

[0045] Fig. 4 shows the details of the change control process used in the Fig. 3 is executed. The change control process is a process in which a post-processing process related to the throttle opening angle for gradually reducing the throttle opening angle from an angle at a start of the ignition timing / throttle opening angle change process to a reduced throttle opening angle F th , and a post-processing process related to the ignition timing for gradually advancing the ignition timing from a point in time at the start of the ignition timing / throttle opening angle change process to an advanced ignition timing F ig be executed at the same time. The change control process includes a process for limiting the actual throttle opening angle so that it does not become less than or equal to a threshold value (throttle opening angle limit value) of the throttle opening angle at which the fuel cutoff control process is started.

[0046] In the change control process, the engine control unit 21 first sets a count value n used in the change control process to “1” in step S21.

[0047] The engine control unit 21 calculates a reduction unit value Q in step S22 according to the following equations (2), (3) and (1) th to be used when the throttle opening angle is gradually reduced, a progression unit value Q ig to be used when the ignition timing progresses gradually, and the frequency K that the throttle opening angle changes by the unit value Q th is reduced, and the ignition timing is increased by the unit value Q ig(a total frequency of execution) is advanced based on a time (execution time) Tt required to change the throttle opening angle from an angle at a start of the ignition timing / throttle opening angle changing process to a reduced throttle opening angle F th and to advance the ignition timing from a point in time at the start of the ignition timing / throttle opening angle change process to an advanced ignition timing F ig to progress, a unit time T'' of a gradual reduction of the throttle opening angle and a gradual progression of the ignition timing, an engine rotational speed detection value P ne at the start of the ignition timing / throttle opening angle change process, an accelerator position detection value P a at the start of the ignition timing / throttle opening angle change process, a throttle opening angle detection value P that the start of the ignition timing / throttle opening angle change process, the reduced throttle opening angle F th and the advanced ignition timing F ig : K = Tt / Tu Qth = (Pth−Fth) / K Qig = (Fig−Pig) / K.

[0048] In the embodiment, the execution time Tt and the unit time T u set in advance.

[0049] In step S23, the engine control unit 21 calculates a target value (intermediate target value) M th a reduction of the throttle opening angle by the unit value Q th and a target value (intermediate target value) M ig an advance of the ignition timing by the standard value Q ig according to the following equations (4) and (5) based on the unit values ​​Q th and Q ig , the throttle opening angle detection value P that the start of the ignition timing / throttle opening angle change process, the ignition timing detection value P ig at the start of the ignition timing / throttle opening angle change process, and a count value n at the present time: Mth = Pth - Qth × n Mig = Pig + Qig × n.

[0050] The engine control unit 21 judges in step S24 whether the intermediate target value M calculated in step S23 th is less than or equal to the throttle opening angle limit.

[0051] If the intermediate target value M th is greater than the throttle opening angle limit value (S24: no), the engine control unit 21 outputs a control signal C in step S25 th to set the throttle opening angle to the intermediate target value M th to the electronically controlled throttle 11 and outputs a control signal C igto the ignition device 12 with such a timing that the ignition timing is equal to the intermediate target value M ig becomes.

[0052] The engine control unit 21 increments the count value n by 1 in step S26 and judges in step S27 whether the count value n is greater than the total frequency of execution K.

[0053] If the count value n is not greater than the total frequency of execution K (S27: no), the engine control unit 21 waits for the unit time T in step S28 u and returns to step S23.

[0054] The engine control unit 21 repeatedly executes steps S23 to S28 as long as the intermediate target value M th is greater than the throttle opening angle limit, and the count value n is not greater than the total frequency of an execution K.

[0055] On the other hand, if the intermediate target value M this less than or equal to the throttle opening angle threshold (S24: yes), the engine control unit 21 terminates the change control process. If the count value n is greater than the total number of executions K, the engine control unit 21 also terminates the change control process.

[0056] As described above, according to the ignition timing / throttle opening angle changing process of the engine control device 1, while the vehicle is running, the ignition timing can be further advanced from a timing determined by the ordinary ignition timing control process. This enables the fuel efficiency of the vehicle to be further improved. Although the fuel efficiency of the vehicle can be improved by advancing the ignition timing through the ordinary ignition timing control process, the fuel efficiency of the vehicle can be made even better by advancing the ignition timing through the ignition timing / throttle opening angle changing process from a timing determined by the ordinary ignition timing control process, compared to the case where only the ordinary ignition timing control process is executed.

[0057] According to the ignition timing / throttle opening angle changing process of the engine control device 1, while the vehicle is traveling, the torque of the engine 2 can be kept constant by further advancing the ignition timing from a timing determined by the ordinary ignition timing control process and, at the same time, further decreasing the throttle opening angle from an angle determined by the ordinary throttle opening angle control process. This makes it possible to prevent a phenomenon that the vehicle is accelerated even though the driver keeps the accelerator pedal at the same position. Thus, the ignition timing can be further advanced from a timing determined by the ordinary ignition timing control process to improve fuel efficiency without deteriorating the maneuverability of the vehicle.

[0058] In the change control process of the engine control device 1, although the throttle opening angle is reduced by the ignition timing / throttle opening angle change process, the reduction of the throttle opening angle is limited so that the throttle opening angle does not become less than or equal to the throttle opening angle limit value (i.e., the throttle opening angle threshold value at which the fuel cut control process is started). This makes it possible to prevent a phenomenon that the fuel cut control process is executed because the throttle opening angle is reduced by the ignition timing / throttle opening angle change process, and consequently, the torque of the engine 2 changes, causing the vehicle to run unstably.

[0059] In the change control process of the engine control device 1, the throttle opening angle is changed from an angle at the start of the ignition timing / throttle opening angle change process to a reduced throttle opening angle F th gradually reduced, and the ignition timing gradually advances from a point at the start of the ignition timing / throttle opening angle change process to an advanced ignition timing F ig by executing the change control process. This makes it possible to prevent a phenomenon that the throttle opening angle or the ignition timing changes rapidly in the ignition timing / throttle opening angle change process, thereby reducing the stability of vehicle driving.

[0060] This is described in more detail below. In the ignition timing / throttle opening angle change process, a reduced throttle opening angle F thand an advanced ignition timing F ig determined so that the torque of engine 2 remains the same even if the throttle opening angle and the ignition timing are changed. If the throttle opening angle changes from an angle at the start of the ignition timing / throttle opening angle change process to the reduced throttle opening angle F th is immediately reduced, or the ignition timing is advanced from a point in time at the start of the ignition timing / throttle opening angle change process to the advanced ignition timing F ig is advanced immediately, the torque of the engine 2 would change greatly immediately when the throttle opening angle is reduced or the ignition timing is advanced, causing the vehicle to experience vibration, such as vibration caused by sudden, irregular acceleration. The engine control device 1 can prevent such vibration.

[0061] Although the ignition timing / throttle opening angle changing process of the above-described embodiment is such that a reduced throttle opening angle F th based on an engine speed detection value P ne , an accelerator position detection value P a and the reduced throttle opening angle map 33, the invention is not limited to this case. Instead, a reduced throttle opening angle F th based on an engine speed detection value P ne , a throttle opening angle detection value P th and the reduced throttle opening angle map 33. In this case, the reduced throttle opening angle map 33 is made into a three-dimensional map indicating a relationship between the engine rotation speed, the throttle opening angle, and the reduced throttle opening angle.

[0062] Although the ignition timing / throttle opening angle changing process of the above embodiment is such that an advanced ignition timing F ig based on an engine speed detection value P ne , a throttle opening angle detection value P th and the advanced ignition timing map 43, the invention is not limited to this case. Instead, the advanced ignition timing F ig based on an engine speed detection value P ne , an accelerator position detection value P a and the advanced ignition timing map 34. In this case, the advanced ignition timing map 34 is made into a three-dimensional map indicating a relationship between the engine rotational speed, the accelerator position, and the advanced ignition timing.

[0063] Although the ignition timing / throttle opening angle changing process of the above embodiment is such that a reduced throttle opening angle F th based on an engine speed detection value P ne , an accelerator position detection value P a and the reduced throttle opening angle map 33, and the throttle opening angle is changed from an angle at the start of the ignition timing / throttle opening angle change process to the reduced throttle opening angle F th is reduced, the invention is not limited to this case. Instead, the ignition timing / throttle opening angle changing process may be such that a throttle opening angle reduction corresponding to the difference between a throttle opening angle detection value P th and a reduced throttle opening angle F th based on an engine speed detection value P ne, an accelerator position detection value P a (or a throttle opening angle detection value P th ) and the reduced throttle opening angle map 33, and the throttle opening angle is reduced from an angle at the start of the ignition timing / throttle opening angle change process by the determined throttle opening angle reduction. In this case, the reduced throttle opening angle map 33 is made into a three-dimensional map indicating a relationship between the engine rotation speed, the accelerator position (or throttle opening angle), and the throttle opening angle reduction.

[0064] On the other hand, although the ignition timing / throttle opening angle changing process of the above embodiment is such that an advanced ignition timing F ig based on an engine speed detection value P ne, a throttle opening angle detection value P th and the advanced ignition timing map 34, and the ignition timing is changed from a time at the start of the ignition timing / throttle opening angle changing process to the advanced ignition timing F ig is advanced, the invention is not limited to this case. Instead, the ignition timing / throttle opening angle changing process may be such that an ignition timing advance corresponding to the difference between an ignition timing detection value P ig and an advanced ignition timing F ig based on an engine speed detection value P ne , a throttle opening angle detection value P th (or an accelerator position detection value P a), and the advanced ignition timing map 34, and the ignition timing is advanced from a point in time at the start of the ignition timing / throttle opening angle change process by the ignition timing advance. In this case, the advanced ignition timing map 34 is made into a three-dimensional map indicating a relationship between the engine rotation speed, the accelerator position (or the throttle opening angle), and the ignition timing advance.

[0065] The reduced throttle opening angle map 33 indicating the relationship between the engine rotation speed, the accelerator position (or the throttle opening angle), and the throttle opening angle reduction, and the advanced ignition timing map 34 indicating the relationship between the engine rotation speed, the throttle opening angle (or the accelerator position), and the ignition timing advance are specific examples of the “ignition timing advance / throttle opening angle reduction information.”

[0066] A reduced throttle opening angle F th (or throttle opening angle reduction) and an advanced ignition timing F ig (ignition timing advance) can be based on an engine speed detection value P ne , an accelerator position detection value P a (or a throttle opening angle detection value P th), and the ignition timing / throttle opening angle target and advance / decrease information. In this case, the ignition timing / throttle opening angle target and advance / decrease information are made into a data table indicating a relationship between the engine rotation speed, the accelerator position (or throttle opening angle), and the decreased throttle opening angle (or throttle opening decrease) and the advanced ignition timing (or ignition timing advance).

[0067] Although in the ignition timing / throttle opening angle changing process of the above embodiment, the reduced throttle opening angle map 33 and the advanced ignition timing map 34 are used as examples of the ignition timing / throttle opening angle target information used to determine a reduced throttle opening angle F thor an advanced ignition timing F ig used, the invention is not limited to this case. The ignition timing / throttle opening angle target information may, for example, be a calculation formula for calculating a reduced throttle opening angle F th based on an engine speed detection value P ne and an accelerator position detection value P a or a calculation formula for calculating an advanced ignition timing F ig based on an engine speed detection value P ne and a throttle opening angle detection value P th be.

[0068] The Fig.The change control process shown in Figure 4 is only an example. Another method may be used as the process for gradually decreasing the throttle opening angle from an angle at the start of the ignition timing / throttle opening angle change process to a reduced throttle opening angle F th and for gradually advancing the ignition timing from a point in time at the start of the ignition timing / throttle opening angle change process to an advanced ignition timing F ig be used.

[0069] Although in the above embodiment, the change control process includes the process of preventing the throttle opening angle from becoming less than or equal to the throttle opening angle limit value of the fuel cut control process in the ignition timing / throttle opening angle change process, the invention is not limited to this case. It can be prevented that a reduced throttle opening angle Fth less than or equal to the throttle opening angle limit value when determining the reduced throttle opening angle F th based on an engine speed detection value P ne , an accelerator position detection value P a and the reduced throttle opening angle map 33. For example, this method can be implemented by forming a reduced throttle opening angle map 33 that includes reduced throttle opening angles F th which are less than or equal to the throttle opening angle limit.

[0070] If the accelerator angle is slightly decreased (e.g., its change is 0% to -5%) during an execution of the ignition timing / throttle opening angle change process, the throttle opening angle can be prevented from being decreased, so that this decrease in the accelerator angle is reflected.

[0071] This measure makes it possible to prevent a phenomenon in which the throttle opening angle becomes less than or equal to the throttle opening angle limit value according to the start of the fuel-cut control process when the driver has slightly decreased the accelerator angle during execution of the ignition timing / throttle opening angle change process. Consequently, deterioration of the vehicle's driving stability can be prevented.

[0072] Alternatively, execution of the fuel cut control process may be postponed during execution of the ignition timing / throttle opening angle change process. This also allows execution of the fuel cut control process to be inhibited during execution of the ignition timing / throttle opening angle change process, thereby stabilizing the vehicle's driving behavior.

[0073] Although in the above embodiment, a body to be driven by the motor 2 is a vehicle such as a motorcycle, it may be any of other types of vehicles such as a motorized tricycle and an automobile, or even another type of transportation means such as a ship. List of reference symbols 1 engine control device 2 engines 11 electronically controlled throttle 12 Ignition device 13 Fuel control device 15 Crank angle sensor (engine speed detection unit) 16 Throttle position sensor (throttle opening angle detection unit) 17 Accelerator position sensor (accelerator position detection unit) 21 Engine control unit 23 Storage unit 31 ordinary throttle opening angle map (ignition timing / throttle opening angle target information) 32 ordinary ignition timing map (ignition timing / throttle opening angle target information) 33 reduced throttle opening angle map (ignition timing / throttle opening angle target information) 34 advanced ignition timing map (ignition timing / throttle opening angle target information)

Claims

[1] Engine control device (1), comprising: an electronically controlled throttle (11) configured to control a flow rate of an air-fuel mixture flowing into a cylinder (3) of an engine (2) by electronically controlling a throttle opening angle, a fuel injection device (13) configured to inject fuel into air supplied to the cylinder (3), an ignition device (12) configured to ignite an air-fuel mixture present in the cylinder (3), and an engine control unit (21) configured to perform an ignition timing / throttle opening angle changing process for controlling the ignition device (12) and the electronically controlled throttle (11) while an operation of a body to be driven by the engine (2) is in a stationary state, so that a timing of ignition of an air-fuel mixture present in the cylinder (3) is advanced and the throttle opening angle is reduced while keeping a torque of the engine (2) constant, wherein the engine control unit (21) is configured to execute a fuel cut control process in which a supply of fuel to the fuel injector (13) is suspended when the throttle opening angle has become very small, and wherein the engine control unit (21) is configured to control the electronically controlled throttle (11) in the ignition timing / throttle opening angle changing process so that the throttle opening angle does not become less than or equal to a throttle opening angle limit value at which the fuel cut control process is started. [2] Engine control device (1) according to claim 1, further comprising: a motor rotation speed detection unit (15) configured to detect a rotation speed of the motor (2), a throttle opening angle detection unit (16) configured to detect a throttle opening angle, and a storage unit (23) in which ignition timing / throttle opening angle target information is stored, indicating a relationship between the rotational speed, the throttle opening angle, an advanced ignition timing as a target ignition timing of the ignition timing / throttle opening angle changing process, and a reduced throttle opening angle as a target throttle opening angle of the ignition timing / throttle opening angle changing process, wherein: the engine control unit (21) is configured to determine an advanced ignition timing and a reduced throttle opening angle to be achieved while maintaining a torque at a time when the operation of the body to be driven by the engine (2) has been transferred to a steady state, based on a rotational speed detected by the engine rotational speed detection unit (15) when the operation of the body to be driven by the engine (2) has been transferred to a steady state, a throttle opening angle detected by the throttle opening angle detection unit (16) when the operation of the body to be driven by the engine (2) has been transferred to a steady state, and the ignition timing / throttle opening angle target information,and advance the ignition timing to the determined advanced ignition timing and reduce the throttle opening angle to the determined reduced throttle opening angle. [3] Engine control device (1) according to claim 1, further comprising: a motor rotation speed detection unit (15) configured to detect a rotation speed of the motor (2); a throttle opening angle detection unit (16) configured to detect a throttle opening angle, and a storage unit (23) in which ignition timing advance / throttle opening angle reduction information is stored, indicating a relationship between the rotational speed, the throttle opening angle, an ignition timing advance by which the ignition timing is changed in the ignition timing / throttle opening angle changing process, and a throttle opening angle reduction by which the throttle opening angle is changed in the ignition timing / throttle opening angle changing process, wherein: the engine control unit (21) is configured to determine an ignition timing advance and a throttle opening angle reduction to be achieved while maintaining a torque at a time when the operation of the body to be driven by the engine (2) has been transferred to a steady state, based on a rotational speed detected by the engine rotational speed detection unit (15) when the operation of the body to be driven by the engine (2) has been transferred to a steady state, a throttle opening angle detected by the throttle opening angle detection unit (16) when the operation of the body to be driven by the engine (2) has been transferred to a steady state, and the ignition timing advance / throttle opening angle reduction information,and advance the ignition timing by the determined ignition timing advance and decrease the throttle opening angle by the determined throttle opening angle reduction. [4] Engine control device (1) according to claim 1, further comprising: a motor rotation speed detection unit (15) configured to detect a rotation speed of the motor (2), an accelerator position detection unit (17) configured to detect an accelerator position, and a storage unit (23) in which ignition timing / throttle opening angle target information is stored, indicating a relationship between the rotational speed, the accelerator position, an advanced ignition timing as a target ignition timing of the ignition timing / throttle opening angle changing process, and a reduced throttle opening angle as a target throttle opening angle of the ignition timing / throttle opening angle changing process, wherein: the engine control unit (21) is configured to determine an advanced ignition timing and a reduced throttle opening angle to be achieved while maintaining a torque at a time when the operation of the body to be driven by the engine (2) has been transferred to a steady state, based on a rotational speed detected by the engine rotational speed detection unit (15) when the operation of the body to be driven by the engine (2) has been transferred to a steady state, an accelerator position detected by the accelerator position detection unit (17) when the operation of the body to be driven by the engine (2) has been transferred to a steady state, and the ignition timing / throttle opening angle target information,and advance the ignition timing to the determined advanced ignition timing and reduce the throttle opening angle to the determined reduced throttle opening angle. [5] Engine control device (1) according to claim 1, further comprising: a motor rotation speed detection unit (15) configured to detect a rotation speed of the motor (2), an accelerator position detection unit (17) configured to detect an accelerator position, and a storage unit (23) in which ignition timing advance / throttle opening angle reduction information is stored indicating a relationship between the rotational speed, the accelerator position, an ignition timing advance by which the ignition timing is changed in the ignition timing / throttle opening angle changing process, and a throttle opening angle reduction by which the throttle opening angle is changed in the ignition timing / throttle opening angle changing process, wherein: the engine control unit (21) is configured to determine an ignition timing advance and a throttle opening angle reduction to be achieved while maintaining a torque at a time when the operation of the body to be driven by the engine (2) has been transferred to a steady state, based on a rotational speed detected by the engine rotational speed detection unit (15) when the operation of the body to be driven by the engine (2) has been transferred to a steady state, an accelerator position detected by the accelerator position detection unit (17) when the operation of the body to be driven by the engine (2) has been transferred to a steady state, and the ignition timing advance / throttle opening angle reduction information,and advance the ignition timing by the determined ignition timing advance and decrease the throttle opening angle by the determined throttle opening angle reduction. [6] The engine control device (1) according to any one of claims 1 to 5, wherein the body to be driven by the engine (2) is a vehicle, and the engine control unit (21) is configured to execute the ignition timing / throttle opening angle changing process when the vehicle has been transferred to a running state.

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