Engine control device

Abstract

The present invention provides an engine control device for an engine connected to a manual transmission via a clutch, which can improve the engine's ability to restart after it stalls due to an error in clutch engagement during vehicle starting (when the clutch is engaged). [Solution] When starting, if the engine speed decreases after the clutch 60 begins to engage, the ECU 50 determines whether combustion occurred or misfires occurred each time fuel is injected (supplied) from the time the clutch 60 begins to engage until the engine 10 stalls. If it determines that a misfire occurred, it counts the number of misfires, calculates a reduction correction value according to the number of misfires, and uses that reduction correction value to reduce the fuel injection amount (fuel supply amount) when restarting after the engine stalls.

Description

Technical Field

[0001] The present invention relates to an engine control device.

Background Art

[0002] Conventionally, vehicles equipped with an engine and a manual transmission connected to the engine via a clutch have been used. In recent years, for example, there is a tendency to adopt a manual transmission in vehicles suitable for sports driving.

[0003] In a vehicle equipped with a manual transmission, at the time of starting, in order not to stall the engine, for example, the accelerator pedal is slightly depressed to slightly increase the engine speed (i.e., engine torque), and the depression of the clutch pedal is gradually released (returned), and a series of operations (clutch engagement operations) of gradually engaging the clutch (through the so-called semi-clutch state) are required (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, when starting by engaging the clutch, for example, if the clutch is suddenly engaged, the wrong gear position (such as second gear or third gear) is selected, or the depression of the accelerator pedal is shallow (or none) and the increase in engine speed (engine torque) is insufficient, and if the clutch engagement operation is incorrect, the engine speed may drop and the engine may stall. And in such a case, the starting performance of the engine may deteriorate when the engine is restarted later.

[0006] The present invention was made to solve the above problems, and aims to provide an engine control device for an engine connected to a manual transmission via a clutch, which can improve the restartability of the engine after it stalls due to an error in clutch engagement operation when the vehicle starts (when the clutch is engaged). [Means for solving the problem]

[0007] An engine control device according to one aspect of the present invention is an engine control device connected to a manual transmission via a clutch, and comprises a control unit that controls the amount of fuel supplied to the engine. The control unit, when starting, if the engine speed decreases after the clutch is engaged, determines whether combustion or misfire occurred each time fuel is supplied from the time the clutch is engaged until the engine stalls. If it determines that a misfire occurred, it counts the number of misfires, calculates a reduction correction value according to the number of misfires, and uses the reduction correction value to reduce the amount of fuel supplied when restarting the engine after it stalls.

[0008] According to an engine control device in one aspect of the present invention, when starting, if the engine speed decreases after the clutch engages, it is determined whether combustion or misfire occurred each time fuel is supplied from the time the clutch engages until the engine stalls. If a misfire is determined, the number of misfires is counted. A reduction correction value is then calculated according to the number of misfires, and when restarting the engine after it stalls, the fuel supply amount is reduced using this reduction correction value. As a result, the air-fuel ratio (λ (air excess ratio)) is optimized by reducing the fuel supply amount at the time of restarting the engine after it stalls, based on the reduction correction value corresponding to the remaining fuel amount due to misfires (for example, over-richness is avoided). Therefore, the restartability after engine stalling can be improved. [Effects of the Invention]

[0009] According to the present invention, in a control device for an engine connected to a manual transmission via a clutch, it is possible to improve the restartability of the engine after it stalls due to an error in clutch engagement operation during vehicle starting (when the clutch is engaged). [Brief explanation of the drawing]

[0010] [Figure 1] This figure shows an engine control device according to an embodiment, and the configuration of an engine to which the control device is applied. [Figure 2] A block diagram showing the configuration of a vehicle equipped with an engine control device according to the embodiment. [Figure 3] This figure shows an example of a weight loss correction value map (lookup table). [Figure 4] This figure shows an example of a water temperature correction value map (lookup table). [Figure 5] This timing chart shows an example of changes in engine speed, fuel injection timing for each cylinder, and misfire count (misfire counter value) for each cylinder during engine stall. [Figure 6] This flowchart shows the processing procedure for misfire count processing (weight reduction correction value acquisition processing) when the engine stalls, performed by the control device of the engine according to the embodiment. [Figure 7] This flowchart shows the processing procedure (fuel injection process) for restarting the engine after stalling by the engine control device according to the embodiment. [Modes for carrying out the invention]

[0011] Preferred embodiments of the present invention will be described in detail below with reference to the drawings. In the drawings, the same or corresponding parts will be denoted by the same reference numerals. In addition, in each drawing, the same elements will be denoted by the same reference numerals, and redundant explanations will be omitted.

[0012] First, the configuration of the engine control device 1 according to the embodiment will be described using Figures 1 and 2 together. Figure 1 is a diagram showing the configuration of the engine control device 1 and the engine 10 to which the control device 1 is applied. Figure 2 is a block diagram showing the configuration of a vehicle (rear-wheel drive vehicle) on which the engine control device 1 is installed.

[0013] Engine 10 is, for example, a horizontally opposed four-cylinder gasoline engine. Engine 10 is also an in-cylinder injection engine that directly injects fuel into the cylinders. In engine 10, air drawn in from the air cleaner 16 is restricted by an electronically controlled throttle valve (hereinafter also simply called "throttle valve") 13 provided in the intake manifold 15, passes through the intake manifold 11, and is drawn into each cylinder formed in engine 10. Here, the amount of air drawn in from the air cleaner 16 is detected by an airflow meter 14 placed between the air cleaner 16 and the throttle valve 13. A vacuum sensor 30 for detecting the pressure inside the intake manifold 11 (intake manifold pressure) is also provided inside the collector section (surge tank) that constitutes the intake manifold 11. Furthermore, a throttle opening sensor 31 for detecting the opening degree of the throttle valve 13 is provided on the throttle valve 13.

[0014] The cylinder head has an intake port 22 and an exhaust port 23 for each cylinder (only one bank is shown in Figure 1). Each intake port 22 and exhaust port 23 is provided with an intake valve 24 and an exhaust valve 25 that open and close the intake port 22 and exhaust port 23, respectively. Between the intake camshaft that drives the intake valve 24 and the intake cam pulley, a variable valve timing mechanism 26 is provided to advance or retard the valve timing (opening / closing timing) of the intake valve 24 by rotating the intake cam pulley and the intake camshaft relative to each other, thereby continuously changing the rotational phase (displacement angle) of the intake camshaft with respect to the crankshaft 10a. This variable valve timing mechanism 26 allows the opening and closing timing of the intake valve 24 to be variably set according to the engine operating conditions.

[0015] Similarly, between the exhaust camshaft and the exhaust cam pulley, a variable valve timing mechanism 27 is provided that relatively rotates the exhaust cam pulley and the exhaust camshaft to continuously change the rotational phase (displacement angle) of the exhaust camshaft with respect to the crankshaft 10a, thereby advancing or retarding the valve timing (opening and closing timing) of the exhaust valve 25. The opening and closing timing of the exhaust valve 25 is variably set according to the engine operating state by this variable valve timing mechanism 27.

[0016] In each cylinder of the engine 10, an injector 12 for injecting fuel into the cylinder is attached. The injector 12 directly injects the fuel pressurized by a high-pressure fuel pump (not shown) into the combustion chamber of each cylinder.

[0017] Further, on the cylinder head of each cylinder, a spark plug 17 for igniting the air-fuel mixture and an in-ignitor coil 21 for applying a high voltage to the spark plug 17 are attached. In each cylinder of the engine 10, the air-fuel mixture of the inhaled air and the fuel injected by the injector 12 is ignited by the spark plug 17 and burns. The exhaust gas after combustion is discharged through the exhaust pipe 18.

[0018] An air-fuel ratio sensor 19 is attached downstream of the collecting portion of the exhaust pipe 18 and upstream of an exhaust purification catalyst 20 described later. As the air-fuel ratio sensor 19, a linear air-fuel ratio sensor (LAF sensor) that can output a signal according to the oxygen concentration and unburned gas concentration in the exhaust gas (that is, a signal according to the air-fuel ratio of the air-fuel mixture) and can linearly detect the air-fuel ratio is used.

[0019] An exhaust purification catalyst 20 is disposed downstream of the air-fuel ratio sensor 19. The exhaust purification catalyst 20 is a three-way catalyst that simultaneously oxidizes hydrocarbons (HC) and carbon monoxide (CO) in the exhaust gas and reduces nitrogen oxides (NOx), and purifies the harmful gas components in the exhaust gas into harmless carbon dioxide (CO2), water vapor (H2O), and nitrogen (N2).

[0020] To the output shaft (crankshaft) 10a of the engine 10, a manual transmission (MT) 70 that converts and outputs the driving force from the engine 10 is connected via, for example, a dry clutch (hereinafter simply referred to as "clutch") 60. The manual transmission 70 is a transmission that manually performs a gearshift operation. For example, a type with concentric input and output shafts is used. As the manual transmission 70, a known one can be used, that is, a transmission in which the driving gears and driven gears of each gear stage are arranged on two shafts, and a synchronization mechanism, a coupling sleeve that operates it, a shift fork, a striking rod, etc. are arranged next to the gears and connected to a shift lever. Note that a clutch switch 61 for detecting the engagement and release (on, off) of the clutch 60 is attached to the clutch 60.

[0021] The driving force output from the engine 10 is converted by the manual transmission 70 and then transmitted from the output shaft 71 of the manual transmission 70 to the left and right rear wheels 80RL, 80RR of the vehicle via, for example, a propeller shaft 72, a rear differential 73 (hereinafter also referred to as "rear diff"), and left and right rear drive shafts 74RL, 74RR.

[0022] In addition to the above-described air flow meter 14, air-fuel ratio sensor 19, vacuum sensor 30, throttle opening sensor 31, and clutch switch 61, a cam angle sensor 32 for discriminating the cylinders of the engine 10 is attached near the camshaft of the engine 10. Also, a crank angle sensor 33 for detecting the rotational position of the crankshaft 10a is attached near the crankshaft 10a of the engine 10. Here, at the end of the crankshaft 10a, a timing rotor 33a having, for example, 34 teeth with two teeth missing and formed at 10° intervals is attached, and the crank angle sensor 33 detects the rotational position of the crankshaft 10a by detecting the presence or absence of the protrusions of the timing rotor 33a. As the cam angle sensor 32 and the crank angle sensor 33, for example, electromagnetic pickup type ones are used.

[0023] These sensors are connected to an engine control unit (hereinafter referred to as "ECU") 50. Furthermore, the ECU 50 is also connected to various other sensors, including a water temperature sensor 34 for detecting the temperature of the engine 10's coolant, an oil temperature sensor 35 for detecting the temperature of the lubricating oil, and an accelerator sensor 36 for detecting the amount the accelerator pedal is pressed, i.e., the amount the accelerator is operated. Here, the engine 10's coolant temperature corresponds to the "index value correlated with the degree of engine warm-up" described in the claims, and the water temperature sensor 34 functions as the detection means described in the claims.

[0024] The ECU 50 is comprised of a microprocessor that performs calculations, an EEPROM that stores programs for the microprocessor to execute various processes, a RAM that stores various data such as calculation results, a backup RAM whose contents are maintained by a battery, and an input / output interface. The ECU 50 also includes an injector driver that drives the injector 12, an output circuit that outputs an ignition signal, and a motor driver that drives an electric motor 13a that opens and closes the electronically controlled throttle valve 13.

[0025] In the ECU 50, the cylinder is identified from the output of the camshaft angle sensor 32, and the crankshaft angular velocity and engine speed are determined from the output of the crankshaft angle sensor 33. For example, the ECU 50 acquires the crankshaft angular velocity (engine speed) at intervals of a certain crankshaft angle (e.g., 30°CA) based on the time change of the rotational position of the crankshaft 10a detected by the crankshaft angle sensor 33. In addition, the ECU 50 acquires the engine speed in a section in which rotational fluctuations when a misfire occurs can be captured, that is, the engine speed during the expansion stroke (compression stroke to) after fuel injection (supply). More specifically, it is preferable that this section be set to include, for example, a region including the timing from when combustion of the air-fuel mixture begins and torque starts to be produced to when combustion is almost finished, for example, the 50% to 90% combustion point (for example, an interval of about 30 to 60°CA).

[0026] Furthermore, the ECU 50 acquires various information such as intake air volume, intake manifold negative pressure, accelerator pedal operation amount, air-fuel ratio of the air-fuel mixture, and engine water temperature and oil temperature of the engine 10, based on detection signals input from the various sensors mentioned above. Based on this acquired information, the ECU 50 comprehensively controls the engine 10 by controlling the fuel injection amount (fuel supply amount), ignition timing, and various devices such as the throttle valve 13.

[0027] In particular, the ECU 50 has a function to improve the restartability of the engine 10 after it stalls due to an error in the clutch engagement operation of the clutch 60 during vehicle starting (when the clutch is engaged). In the ECU 50, this function is realized by the execution of a program stored in the EEPROM by a microprocessor. The ECU 50 corresponds to the control unit described in the claims.

[0028] Therefore, when the vehicle starts moving, if the engine speed decreases after the clutch 60 begins to engage, the ECU 50 first determines whether combustion occurred or a misfire occurred each time fuel is injected (supplied) from the start of clutch 60 engagement until the engine 10 stalls. More specifically, each time fuel is injected (supplied), the ECU 50 detects the engine speed including the expansion stroke after fuel injection (supply), and determines that a misfire occurred if the engine speed does not increase. At that time, the ECU 50 obtains the engine speed including the expansion stroke after fuel injection (supply) for each cylinder of the engine 10 and determines whether or not a misfire occurred.

[0029] The ECU50 then counts the number of misfires when it determines that a misfire has occurred. The ECU50 has a misfire counter that counts the number of misfires for each cylinder.

[0030] On the other hand, if the engine speed increases, including the expansion stroke after fuel injection (supply), the ECU 50 determines that combustion has occurred and clears the misfire count (resets the misfire counter). A predetermined threshold may be set for determining whether combustion or misfire has occurred. That is, if the engine speed including the expansion stroke does not rise above a predetermined threshold, it may be determined that a misfire has occurred, and if it rises above a predetermined threshold, it may be determined that combustion has occurred.

[0031] Next (after engine 10 stalls), ECU 50 calculates a reduction correction value based on the number of misfires. At this time, ECU 50 calculates a reduction correction value for each cylinder based on the number of misfires.

[0032] Here, we will explain how to determine the weight reduction correction value. The ECU50's EEPROM stores a map (weight reduction correction value map) that defines the relationship between the number of misfires (misfire count value) and the weight reduction correction value. The weight reduction correction value is obtained by searching this weight reduction correction value map based on the number of misfires (misfire count value).

[0033] Here, an example of a weight reduction correction value map is shown in Figure 3. In Figure 3, the horizontal axis (rows) represents the number of misfires (misfire count value). In the weight reduction correction value map, a weight reduction correction value (msec or cc) is given for each number of misfires (grid point). The weight reduction correction value map is set so that the weight reduction correction value increases as the number of misfires (misfire count value) increases. Note that the data for this weight reduction correction value map can be obtained, for example, through calibration or simulation.

[0034] Furthermore, the ECU 50 decreases the fuel reduction correction value based on the coolant temperature of the engine 10, as the coolant temperature increases (i.e., as the engine 10 warms up). Incidentally, as the coolant temperature increases (as the engine 10 warms up), the amount of fuel adhering to the liner, piston head, etc., that vaporizes (volatilizes) and is discharged in the exhaust stroke increases, thus reducing the amount of remaining fuel. Therefore, the ECU 50 decreases the fuel reduction correction value as the coolant temperature increases (as the engine 10 warms up).

[0035] More specifically, the ECU50 multiplies the weight reduction correction value by a water temperature correction value (correction coefficient ≤ 1) corresponding to the coolant temperature, and obtains the weight reduction correction value after water temperature correction.

[0036] Here, we will explain how to determine the water temperature correction value. The ECU50's EEPROM stores a map (water temperature correction value map) that defines the relationship between coolant temperature and the water temperature correction value. The water temperature correction value (coefficient) is obtained by searching this water temperature correction value map based on the coolant temperature.

[0037] Here, an example of a water temperature correction value map is shown in Figure 4. In Figure 4, the horizontal axis (rows) represents the coolant temperature (°C). In the water temperature correction value map, a water temperature correction value (correction coefficient ≤ 1) is given for each coolant temperature (grid point). In the water temperature correction value map, the water temperature correction value (correction coefficient) is set to decrease as the coolant temperature increases (for example, it is set to "1" at 10°C, "0.6" at 50°C, and "0" at 90°C). Note that the data for this water temperature correction value map can be obtained, for example, through fitting or simulation.

[0038] Then, when the engine is restarted after stalling, the ECU 50 reduces the target fuel injection amount (target fuel supply amount) using the reduced amount correction value after water temperature correction. At that time, the ECU 50 corrects the target fuel injection amount (target fuel supply amount) for each cylinder when the engine is restarted after stalling. Then, for each cylinder, the ECU 50 drives the injector 12 (i.e., performs fuel injection) based on the reduced amount corrected target fuel supply amount (target fuel injection amount).

[0039] Next, the operation of the engine control device 1 will be explained with reference to Figures 5, 6, and 7. Here, Figure 5 is a timing chart showing an example of changes in engine speed, fuel injection timing for each cylinder, and misfire count (misfire counter value) for each cylinder during engine stall. The horizontal axis of Figure 5 represents time, and the vertical axis, from top to bottom, shows the clutch switch 61 (engagement and disengagement of clutch 60), rotational speed drop determination flag, engine speed including expansion stroke, fuel injection timing for each cylinder, and misfire count (misfire counter value) for each cylinder. Figure 6 is a flowchart showing the processing procedure of the misfire count processing (weight reduction correction value acquisition processing) during engine stall by the engine control device 1. Figure 7 is a flowchart showing the processing procedure of the restart processing (fuel injection processing) after engine stall by the engine control device 1. This processing is repeatedly executed at predetermined timings in the ECU 50.

[0040] First, referring to Figure 6, the misfire count processing (weight reduction correction value acquisition processing) during engine stall will be explained. In step S100, a determination is made as to whether or not the clutch 60 has started to engage when the vehicle starts moving. If the clutch 60 has not started to engage, the process is temporarily exited. On the other hand, when the clutch 60 has started to engage (see time t0 in Figure 5), the process moves to step S102.

[0041] In step S102, a determination is made as to whether or not the engine speed has decreased. If the engine speed has not decreased, the process is temporarily exited. On the other hand, if the engine speed has decreased, in step S104, a speed decrease determination flag is set to indicate that the engine speed has decreased after the clutch engagement started (see time t2 in Figure 5), and then the process proceeds to step S106.

[0042] In step S106, for each cylinder, the engine speed including the expansion stroke after fuel injection (supply) is obtained each time fuel is injected (supplied).

[0043] Next, in step S108, a determination is made for each cylinder as to whether the engine speed, including the expansion stroke after fuel injection (supply), has increased. If the engine speed, including the expansion stroke, has increased, it is determined that the fuel has burned, and in step S110, after the misfire count is cleared (after the misfire counter is reset) (see times t4 and t7 in Figure 5), the process proceeds to step S114. On the other hand, if the engine speed, including the expansion stroke, has not increased, it is determined that a misfire has occurred, and in step S112, after the misfire count is recorded (after the misfire counter is counted up) (see times t3, t5, t6, t8, t9, t10, and t11 in Figure 5), the process proceeds to step S114.

[0044] In step S114, a determination is made as to whether or not the engine 10 has stalled (stopped). If the engine 10 has not stalled, the process returns to step S106, and the processes described in steps S106 to S114 are executed again (repeatedly). On the other hand, if the engine 10 has stalled (see time t11 in Figure 5), the process proceeds to step S116.

[0045] In step S116, a weight reduction correction value is calculated for each cylinder according to the number of misfires. The method for calculating the weight reduction correction value is as described above, so a detailed explanation is omitted here. For example, in the examples in Figures 5 and 3, the number of misfires is 1 for cylinder #1, 2 for cylinder #2, 2 for cylinder #3, and 1 for cylinder #4, and the weight reduction correction values ​​are 10 for cylinder #1, 20 for cylinder #2, 20 for cylinder #3, and 10 for cylinder #4.

[0046] Next, in step S118, a water temperature correction value (coefficient) is obtained for each cylinder based on the coolant temperature of the engine 10, and the weight reduction correction value is multiplied by the water temperature correction value (coefficient) to obtain the weight reduction correction value after water temperature correction. After that, the process is temporarily exited. As the method for determining the water temperature correction value (coefficient) is as described above, a detailed explanation is omitted here. Here, for example, in the example in Figure 4, the weight reduction correction value is multiplied by 1 at a water temperature of 10°C, by 0.6 at 50°C, and by 0 at 90°C.

[0047] Next, referring to Figure 7, the restart process (fuel injection process) after engine stall will be explained. First, in step S200, a determination is made as to whether or not the restart (cranking) after engine stall has started. If the restart (cranking) after engine stall has not started, the process is temporarily exited. On the other hand, if the restart (cranking) after engine stall has started, the process moves to step S202.

[0048] In step S202, the target fuel injection amount (target fuel supply amount) is reduced for each cylinder using a reduced amount correction value after water temperature correction. Then, in the following step S204, the injector 12 is driven (i.e., fuel injection is performed) for each cylinder based on the reduced amount corrected target fuel injection amount (target fuel supply amount). After that, the process is temporarily exited.

[0049] As explained in detail above, according to this embodiment, when starting, if the engine speed decreases after the clutch 60 begins to engage, it is determined whether combustion or misfire occurred each time fuel is injected (supplied) from the start of clutch 60 engagement until the engine 10 stalls. If it is determined that a misfire occurred, the number of misfires is counted. A reduction correction value is then calculated according to the number of misfires, and when restarting the engine after it stalls, the target fuel injection amount (target fuel supply amount) is reduced using this reduction correction value. As a result, the reduction correction value corresponding to the remaining fuel amount due to misfires is reduced from the target fuel injection amount (target fuel supply amount) when restarting the engine after it stalls, thereby optimizing the air-fuel ratio (λ (air excess ratio)) (for example, over-richness is avoided). Thus, the restartability after engine stalling can be improved.

[0050] As a result, it becomes possible to improve the restartability of the engine 10 after it stalls due to an error in engaging the clutch 60 during vehicle startup (when the clutch is engaged). For example, it becomes possible to shorten the time required from initial combustion to complete combustion during restart, and to improve exhaust emissions during restart.

[0051] According to this embodiment, each time fuel is injected (supplied), the engine speed including the expansion stroke after fuel injection (supply) is acquired, and if the engine speed does not increase, it is determined that a misfire has occurred. Therefore, it is possible to accurately determine whether or not a misfire has occurred.

[0052] According to this embodiment, when the engine speed increases, including the expansion stroke after fuel injection (supply), it is determined that the fuel has burned, and the misfire count is cleared (the misfire counter is reset). However, when fuel burns, any remaining fuel also burns (is consumed). Therefore, by clearing the misfire count, the amount of remaining fuel can be (re)appropriately estimated. Thus, for example, it is possible to avoid the air-fuel ratio becoming over-lean during restart.

[0053] According to this embodiment, misfires are detected for each cylinder of the engine 10, the number of misfires is counted for each cylinder, a reduction correction value is calculated for each cylinder, and the amount of fuel supplied to each cylinder during restart after engine stall is corrected. As a result, the air-fuel ratio during restart after engine stall can be optimized for each cylinder, further improving restartability.

[0054] According to this embodiment, based on the coolant temperature of the engine 10, the reduction correction value at restart decreases as the coolant temperature increases (as the engine 10 warms up). Therefore, when the amount of remaining fuel decreases as the engine 10 warms up (coolant temperature increases) and the amount of remaining fuel vaporized (volatilized) and discharged in the exhaust stroke increases, the reduction correction value can be reduced to further optimize the air-fuel ratio, thereby improving the restartability after engine stall.

[0055] Although embodiments of the present invention have been described above, the present invention is not limited to the above embodiments and can be modified in various ways. For example, in the above embodiments, the present invention was described using the case where it is applied to an in-cylinder injection type engine 10 as an example, but the present invention can also be applied to a port injection type engine or an engine that combines in-cylinder injection and port injection.

[0056] Furthermore, although the above embodiments described the present invention as being applied to a rear-wheel-drive (FR) vehicle, the present invention can also be applied to front-wheel-drive (FF) vehicles and all-wheel-drive (AWD) vehicles.

[0057] In the above embodiment, the number of misfires until the engine 10 stalls was counted, but instead of counting the number of misfires, the fuel injection amount (fuel supply amount) at the time of misfire may be accumulated. Then, a reduction correction value may be calculated (obtained) from that accumulated value.

[0058] Furthermore, the dimensions, materials, and other specific numerical values ​​shown in the above embodiments are illustrative examples to facilitate understanding of the present invention and do not limit the present invention unless otherwise specified. [Explanation of symbols]

[0059] 1. Engine control system 10 Engines 10a Crankshaft 11 Intake Manifold 12 Injectors 13. Electronically controlled throttle valve 14. Airflow meter 17 Spark plugs 21 Igniter-integrated coil 19. Air-fuel ratio sensor (LAF sensor) 31 Throttle position sensor 32 Cam angle sensor 33 Crank Angle Sensor 33a Timing rotor 34. Water temperature sensor 35 Oil temperature sensor 36 Accelerator sensor 50 ECU (Control Unit) 60 Clutch 61 Clutch switch 70 Manual transmission 71 Output shaft 72 Propeller Shaft 73 Rear Differential 74RL, 74RR Rear Drive Shaft 80RL, 80RR rear wheel

Claims

1. A control device for an engine to which a manual transmission is connected via a clutch, The engine is equipped with a control unit that controls the amount of fuel supplied to the engine, The control unit, when starting, if the engine speed decreases after the clutch has started to engage, From the start of clutch engagement until the engine stalls, it is determined whether combustion or misfire occurred each time fuel is supplied. If it is determined that a misfire occurred, the number of misfires is counted, and a reduction correction value is calculated according to the number of misfires. When restarting the engine after it has stalled, the fuel supply amount is reduced using the reduction correction value. An engine control device characterized by the following:

2. The control unit for the engine according to claim 1 is characterized in that, each time fuel is supplied, it obtains the engine speed including the expansion stroke after fuel supply, and determines that a misfire has occurred if the engine speed does not increase.

3. The control unit for the engine according to claim 2 is characterized in that, when the engine speed increases, including the expansion stroke after fuel supply, it determines that combustion has occurred and clears the misfire count.

4. The control unit for the engine according to claim 3 is characterized in that it determines whether or not each cylinder of the engine has misfired, counts the number of misfires for each cylinder, calculates a reduction correction value for each cylinder, and corrects the amount of fuel supplied for each cylinder when restarting after the engine stalls.

5. The system includes a detection means for detecting an index value that correlates with the degree of engine warm-up, The control unit is characterized in that, based on the index value detected by the detection means, it reduces the weight reduction correction value as the engine warms up. This is the engine control device according to claim 4.

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