Spark ignition engine

Abstract

To provide a spark ignition type engine which can alleviate a torque shock at a transition from a quick acceleration operation to a normal operation.SOLUTION: A spark ignition type engine comprises a quick acceleration operation detection sensor. When a quick acceleration operation is not detected by the control of an electronic control device, normal operation processing is performed, and when the quick acceleration operation is detected, the quick acceleration processing transitions to normal operation processing after the quick acceleration processing is performed for a necessary continuous period, and in the quick acceleration processing, an advance angle of ignition timing is set larger than that at the normal operation processing, and chronologically retarded during the necessary continuous period of the quick acceleration processing. By this constitution, at a transition from the quick acceleration processing having a large advance angle which is favorable in acceleration responsiveness to the normal operation processing having a small advance angle which is favorable in knocking prevention performance, the abrupt lowering of an output caused by the abrupt lowering of the advance angle can be avoided, and a torque shock can be alleviated.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present invention relates to a spark ignition engine, and more particularly to a spark ignition engine capable of reducing torque shock when transitioning from rapid acceleration operation to normal operation. [Background technology]

[0002] Conventionally, there is a spark ignition engine in which the ignition timing is advanced during rapid acceleration (see, for example, Patent Document 1). In this type of engine, acceleration response can be improved by advancing the timing. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 59-145364 (see Figure 11) Summary of the Invention [Problem to be solved by the invention]

[0004] In the engine of the above-mentioned patent document, when transitioning to normal operation after the ignition timing is advanced for rapid acceleration operation, the ignition timing is suddenly retarded, which may cause a torque shock due to a drop in output caused by a sudden decrease in the advance angle.

[0005] An object of the present invention is to provide a spark ignition engine capable of reducing torque shock when transitioning from rapid acceleration to normal operation. [Means for solving the problem]

[0006] The main configuration of the present invention is as follows. As shown in FIG. 1, the vehicle is equipped with a sudden acceleration detection sensor (10). Under the control of the electronic control device (5), when a sudden acceleration operation is not detected, a normal driving process is performed as shown in FIG. 6. When a sudden acceleration operation is detected, the sudden acceleration process is performed for a required duration and then the vehicle is shifted to a normal driving process as shown in FIG. 7. In the rapid acceleration process, the advance angle of the ignition timing is set larger than that in the normal driving process, and as shown in FIG. 7, the advance angle is gradually retarded over the required duration of the rapid acceleration process. Consists of As shown in FIG. 1, the engine includes a main intake passage (1), a throttle valve (2) in the main intake passage (1), a bypass intake passage (3) that bypasses the throttle valve (2), an ISC valve (4) in the bypass intake passage (3), and an electronic control device (5) that adjusts the opening of the ISC valve (4) to control the engine speed. As shown in FIG. 1, the engine temperature sensor (6) and the atmospheric pressure sensor (8) are provided. As shown in FIG. 3(A) and FIG. 4(A), the lower the detected engine temperature, the more the base lower limit value (4b) of the ISC valve opening is increased toward the fully open side (4ba). As shown in Figs. 3(A) and 4(A), in the engine mid-high temperature range where the engine temperature exceeds a predetermined value, the base lower limit value (4b) is increased (4ca) toward the fully open side by an increased correction value (4c) based on the detected atmospheric pressure, and in this increased correction (4ca), the increased correction value (4c) is increased (4cb) toward the fully open side as the detected atmospheric pressure decreases. A spark ignition engine characterized in that, as illustrated in Figures 3(B) and 4(A), in a low engine temperature region where the engine temperature is below a predetermined value, the incremental correction (4ca) is prohibited (4cc). Effect of the Invention

[0007] The present invention has the following advantages. When transitioning from rapid acceleration processing with a large advance angle, which provides good acceleration response, to normal operation processing with a small advance angle, which provides good knocking prevention, a sudden drop in output due to a sudden decrease in the advance angle is avoided, and torque shock is reduced. In the low engine temperature range where the base lower limit value (4b) is relatively large, the increase correction (4ca) of the base lower limit value (4b) is prohibited (4cc) as shown in Fig. 3(B) and Fig. 4(A), and an adjustment is made to avoid excessively high engine speeds, thereby preventing engine noise and gear rattle during gear shifting. Furthermore, as shown in FIG. 3(B) and FIG. 4(A), in the medium to high temperature range of the engine where the base lower limit value (4b) is relatively small, during operation at high altitudes, the base lower limit value (4b) is increased (4ca) based on the atmospheric pressure to compensate for the decrease in intake density, thereby preventing the engine from stalling due to incomplete combustion. [Brief description of the drawings]

[0008] [Figure 1] 1 is a block diagram illustrating a main part of a spark ignition engine according to an embodiment of the present invention. [Diagram 2] FIG. 2(A) is a time chart of an engine starting test according to an embodiment of the present invention, and FIG. 2(B) is a time chart of a comparative example. [Diagram 3] FIG. 3A shows a control map for the base lower limit value, and FIG. 3B shows a control map for the increase correction value. [Figure 4]FIG. 4A is a graph showing the control characteristics based on the engine temperature, and FIG. 4B is a graph showing the control characteristics based on the intake air temperature. [Diagram 5] 4 is a flow chart of the control by the electronic control device, showing a flow chart related to engine starting. [Figure 6] 6 is a flowchart of the process after cranking is completed, continuing from FIG. 5 . [Figure 7] 7 is a flowchart of the rapid acceleration process continued from FIG. 6. [Figure 8] 1 is a front view of a spark ignition engine according to an embodiment of the present invention. FIG. [Figure 9] FIG. 9 is a side view of the intake side of the engine of FIG. [Figure 10] FIG. 9 is a plan view of the engine of FIG. 8. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] 1 to 10 are diagrams for explaining a spark ignition engine according to an embodiment of the present invention. In this embodiment, an inclined in-line two-cylinder gasoline engine will be explained.

[0010] As shown in FIG. 9, this engine includes a cylinder block (11), a cylinder head (12) attached to the upper part of the cylinder block (11), a cylinder head cover (13) attached to the upper part of the cylinder head (12), a flange wheel housing (14) provided at one end of the cylinder block (11), a timing transmission device accommodating section (11b) provided at the other end of the cylinder block (11), and an oil pan (15) attached to the lower part of the cylinder block (11). A cylinder is accommodated in the upper part of the cylinder block (11), and a crankshaft (16) is accommodated in the crankcase (11a) in the lower part. As shown in Figure 8, a flywheel (17) is accommodated in the flywheel housing (14). A timing transmission device is accommodated in the timing transmission device accommodation portion (11b). As shown in Figures 9 and 10, the crankshaft (16) is installed in the front-to-rear direction, with one end in the front and the other in the rear, and the flange wheel housing (14) is disposed in the front of the cylinder block (11), and the timing transmission device accommodating portion (11b) is disposed in the rear of the cylinder block (11). The engine includes an intake system, a fuel supply system, an ignition system, an exhaust system, a starting system, and an engine water cooling system.

[0011] The intake system is a device that supplies intake air to the cylinder and includes, in order from the intake upstream side, an air cleaner (not shown), an intake duct (not shown), a throttle body (18) shown in Figures 8 and 10, an intake manifold (19), and an intake port in the cylinder head (12). This engine is of the naturally aspirated type and does not include a turbocharger. The intake manifold (19) is attached to the cylinder head (12) and also serves as a surge tank.

[0012] As shown in FIG. 1, the throttle body (18) is a component that adjusts the amount of intake air, and is attached to the intake manifold (19). The throttle body (18) includes a main intake passage (1), a throttle valve (2) in the main intake passage (1), a bypass intake passage (3) that bypasses the throttle valve (2), and an ISC valve (4) in the bypass intake passage (3). ISC valve is an abbreviation for idling speed control valve, and hereafter we will also use the abbreviation ISC valve.

[0013] In this engine, the opening of the ISC valve (4) is adjusted under the control of an electronic control device (5) shown in FIG. 1 to control the idling speed and the like. The throttle valve (2) is linked to an accelerator pedal (21) through a mechanical governor (20). The electronic control device (5) is a device that electronically controls each part of the engine, and an engine ECU is used. ECU is an abbreviation for electronic control unit. 1, the ISC valve (4) is a valve that adjusts the flow rate of the bypass intake air (3a) passing through the bypass intake passage (3), and is a needle valve that is driven by an ISC valve actuator (4a). A stepping motor is used for the ISC valve actuator (4a).

[0014] The fuel supply device is a device that injects fuel into the intake air to form an air-fuel mixture, and as shown in FIG. 1, is provided with an injector (22). An electromagnetic valve of the injector (22) is opened and closed at a predetermined timing under the control of the electronic control device (5), and a predetermined amount of fuel is injected at a predetermined fuel injection timing. The fuel injection timing and the fuel injection amount are determined by calculations in the electronic control device (5) based on the engine speed, engine temperature, atmospheric pressure, intake pressure, and intake temperature, and on a fuel injection map, to form an air-fuel mixture with an appropriate air-fuel ratio. The fuel injection map is stored in a memory section of the electronic control device (5). The timing of opening and closing of the electromagnetic valve of the injector (22) is specified by the crank angle. The injectors (22) shown in Figures 8 and 10 are inserted into the intake ports of each cylinder in the cylinder head (12). Since this engine has two cylinders, two injectors (22) are provided, as shown in Figure 10.

[0015] The crank angle is detected by a crank position sensor (23) shown in FIG. The engine speed is calculated by the electronic control device (5) on the basis of the rate of change of the crank angle detected by the crank position sensor (23). The engine temperature is detected by an engine temperature sensor (6) shown in FIG. 1 etc., the atmospheric pressure is detected by an atmospheric pressure detection device (8), the intake pressure is detected by an intake pressure sensor (24), and the intake air temperature is detected by an intake air temperature sensor (7). An engine coolant temperature sensor (6a) is used as the engine temperature sensor (6) for detecting the engine temperature. However, an engine oil temperature sensor or a cylinder wall temperature sensor may be used instead. The atmospheric pressure detection device (8) uses an atmospheric pressure sensor (8a) arranged outside the intake path, but it can be replaced by an intake pressure sensor (24) arranged inside the intake path. That is, before the engine is started, when the key switch (29) shown in Fig. 1 is turned from the OFF position (29a) to the ON position (29b), if the intake pressure sensor (24) detects the intake pressure in the intake path, this intake pressure will match the atmospheric pressure. Therefore, even when the engine is started or while the engine is running, the intake pressure before the engine start can be regarded as the atmospheric pressure, and control based on the atmospheric pressure can be performed. This engine is a four-stroke engine, and it is not possible to distinguish between the intake stroke and the expansion stroke, and between the compression stroke and the exhaust stroke of each cylinder by detecting the crank angle alone. Therefore, the cam angle of the valve cam is detected by a cam position sensor (31) shown in FIG. 1 etc., and the electronic control device (5) identifies the stroke of the combustion cycle of each cylinder.

[0016] As shown in Figures 8 and 9, the engine coolant temperature sensor (6) is disposed at a coolant outlet of the head jacket in the cylinder head (12), as shown in Figures 8 to 10, the intake pressure sensor (24) is disposed in the intake manifold (19) as an integral structure with the intake air temperature sensor (7), as shown in Figure 7, the crank position sensor (23) is disposed in the timing transmission device accommodating portion (11b), and as shown in Figures 8 to 10, the cam position sensor (31) is disposed in the cylinder head (13).

[0017] The ignition device is a device that ignites the air-fuel mixture, and as shown in FIG. 1, includes an igniter (25), an ignition coil (26), and a spark plug (27). A spark is emitted from the spark plug (27) at a predetermined ignition timing under the control of the electronic control device (5). The ignition timing is determined by calculation by the electronic control device (5) based on the engine speed, engine coolant temperature, atmospheric pressure, intake pressure, and intake air temperature, and on an ignition timing map. The spark plug (27) is attached to the cylinder head inside the cylinder head cover and fitted into a plug cap (not shown). The ignition coil (26) shown in Figures 8 to 10 is attached to the upper end of the plug cap and disposed above the cylinder head cover (13). Since this engine has two cylinders, two spark plugs (27) are provided, and as shown in FIG. 10, two ignition coils (26) are also provided.

[0018] The exhaust system is a device that discharges exhaust gas from the cylinder, and includes, from the upstream of the exhaust gas, an exhaust port in the cylinder head (12), an exhaust manifold, an exhaust pipe, a three-way catalyst, and an exhaust muffler. These parts are not shown in the drawings.

[0019] The engine water-cooling system is a device that cools the engine with engine cooling water, and is configured so that the engine cooling water in the cylinder jacket in the cylinder block (11) passes through a head jacket in the cylinder head (12), a radiator (not shown), and a water pump (28) in that order, before circulating back to the cylinder jacket. As shown in Figures 9 and 10, the water pump (28) is disposed at the rear of the cylinder block (11).

[0020] The starting device is a device for starting the engine, and as shown in FIG. 1, includes a key switch (29) and a starter (30). When the key switch (29) is turned from the OFF position (29a) to the start position (29c), electricity is supplied to the starter (30) from the battery (not shown), and the crankshaft (16) is driven by cranking. When the engine speed reaches a predetermined cranking end determination value, the pinion gear (not shown) of the starter (30) disengages from the ring gear (shown) of the crankshaft (16), and the power supply from the battery to the starter (30) is also released, thereby ending cranking. The cranking end determination value is set to the full combustion speed (approximately 1,300 revolutions per minute).

[0021] As shown in FIG. 2(A), this engine is configured such that, at engine start, the electronic control device (5) controls the ISC valve (4) to have a cranking opening that is narrowed by a predetermined amount from the full open position, thereby generating an intake negative pressure on the intake downstream side (1b) of the ISC valve (4) shown in FIG. 1. As a result, the negative intake pressure promotes fuel vaporization, improving the mixing of fuel and air, and improving combustion, resulting in better engine startability.

[0022] 2(A) and (B) are time charts of an engine starting test, with FIG. 2(A) showing an embodiment of the present invention and FIG. 2(B) showing a comparative example. In the engine start test of the embodiment of the present invention shown in FIG. 2(A), cranking was performed with the ISC valve (4) set to a cranking opening that was narrowed by a predetermined amount from the full open position. This resulted in a large intake negative pressure being generated during cranking, and the engine speed reached the cranking end determination value (about 1,300 rpm) in a short time (about 2 seconds). After cranking was ended, stable idling operation was maintained for a predetermined time (about 5 seconds). Therefore, it was determined that the engine start was successful, and the engine operation was forcibly terminated, thereby terminating the engine start test.

[0023] On the other hand, as shown in FIG. 2(B), in the engine starting test of the comparative example, the ISC valve (4) was fully opened when cranking was performed, so that the intake negative pressure during cranking was small, and cranking continued for a long period of time (about 7 seconds). After cranking ended, idling was maintained for a short period of time (about 3 seconds), but immediately thereafter, the engine stalled and failed to start. After that, when the engine was restarted in the same way, after a short period of cranking (about 2 seconds), the engine was judged to have been restarted successfully because stable idling was maintained for a long period of time (10 seconds or more). The reason for the success of the restart is believed to be that the engine temperature rose during the initial engine start process. Thus, in the comparative example, the initial engine start failed, whereas in the embodiment, there was no initial engine start failure, and it can be seen that the startability of the engine in the embodiment is good.

[0024] As shown in FIG. 1, this engine is provided with an engine temperature sensor (6) and is configured such that the lower the detected engine temperature is, the greater the cranking opening of the ISC valve (4) is reduced. Therefore, the lower the engine temperature, the greater the intake negative pressure becomes, improving the cold startability of the engine.

[0025] As shown in FIG. 1, this engine includes an intake air temperature sensor (7) and is configured such that the lower the detected intake air temperature is, the more the cranking opening of the ISC valve (4) is reduced. Therefore, the lower the intake temperature, the greater the intake negative pressure becomes, improving the cold startability of the engine.

[0026] The cranking opening is determined by calculation by the electronic control device (5) based on the engine coolant temperature and the intake air temperature, and on a cranking opening map. The cranking opening map is stored in a memory section of the electronic control device (5).

[0027] This engine is configured such that the amount of intake air during cranking is 30% to 70% of the amount when the ISC valve (4) is fully open, by setting the cranking opening of the ISC valve (4). If the intake volume during cranking is less than 30% of that when the ISC valve (4) is fully open, the intake air will be insufficient, and if it exceeds 70%, the intake negative pressure will be insufficient. In either case, engine start failure is likely to occur, but failure is unlikely to occur within the above range.

[0028] As shown in FIG. 2(A), this engine is configured so that the idling opening of the ISC valve (4) immediately after the end of cranking is larger than the cranking opening. As a result, the intake volume increases during idling operation immediately after cranking is completed, stabilizing idling operation.

[0029] As shown in FIG. 1, the engine is equipped with an engine temperature sensor (6) and an atmospheric pressure sensor (8). As shown in FIG. 3(A) and FIG. 4(A), the lower the detected engine temperature, the more the base lower limit value (4b) of the ISC valve opening is increased (4ba) toward the fully open side. As shown in FIG. 4A, in the engine mid-to-high temperature range where the engine temperature exceeds a predetermined value, the base lower limit value (4b) is increased (4ca) toward the fully open side by an increase correction value (4c) based on the detected atmospheric pressure, and as shown in FIG. 3B, in this increase correction (4ca), the increase correction value (4c) is increased (4cb) toward the fully open side as the detected atmospheric pressure becomes lower. As shown in FIG. 3(B) and FIG. 4(A), in the low engine temperature region where the engine temperature is equal to or lower than a predetermined value, the increasing correction (4ca) is prohibited (4cc).

[0030] As shown in Figures 3(A) and 4(A), in this engine, in the low engine temperature range where the base lower limit value (4b) is relatively large, the increase correction (4ca) of the base lower limit value (4b) is prohibited (4cc) as shown in Figures 3(B) and 4(A), and adjustments can be made to avoid excessively high engine speeds, thereby preventing engine noise and gear rattle during gear shifting. The reason why the base lower limit value (4b) is made large in the low engine temperature region is to prevent the engine from stalling due to insufficient power output caused by an increase in the internal load of the engine due to a high viscosity of the engine oil. Furthermore, as shown in FIG. 3(B) and FIG. 4(A), in the medium to high temperature range of the engine where the base lower limit value (4b) is relatively small, during operation at high altitudes, the base lower limit value (4b) is increased (4ca) based on the atmospheric pressure to compensate for the decrease in intake density, thereby preventing the engine from stalling due to incomplete combustion. The base lower limit (4b) can be made small in the medium-high engine temperature range because the internal load of the engine is small and the engine is less likely to stall due to insufficient output.

[0031] As shown in FIG. 3(B) and FIG. 4(A), in the medium to high engine temperature region, the increase correction value (4c) is decreased (4cd) as the detected engine temperature decreases. For this reason, as shown in FIG. 4(A), in the engine medium to high temperature region where the base lower limit value (4b) gradually increases with a decrease in engine temperature, the increase correction value (4c) conversely gradually decreases, making it possible to perform an adjustment to avoid excessively high engine speeds.

[0032] As shown in FIG. 1, the engine is equipped with an intake air temperature sensor (7). As shown in FIGS. 3(A) and 4(A), the base lower limit value (4b) of the ISC valve opening is increased (4bb) toward the fully open side as the detected intake air temperature increases. Therefore, in the intake air medium to high temperature region where the intake air density is relatively low, the base lower limit value (4b) is increased (4bb) to compensate for the decrease in intake air density, thereby preventing engine stall due to incomplete combustion.

[0033] As shown in FIG. 1, this engine is equipped with a sudden acceleration operation detection sensor (10), and under the control of the electronic control device (5), when a sudden acceleration operation is not detected, normal operation processing is performed as shown in FIG. 6, and when a sudden acceleration operation is detected, the sudden acceleration processing is performed for a required duration, and then the engine is transitioned to normal operation processing as shown in FIG. 7. In the rapid acceleration process, the advance angle of the ignition timing is set to be greater than that in the normal operation process, and as shown in FIG. 7, the ignition timing is retarded over time during the required duration of the rapid acceleration process. As a result, when transitioning from rapid acceleration processing with a large advance angle, which provides good acceleration response, to normal operation processing with a small advance angle, which provides good knocking prevention, a sudden drop in output due to a sudden decrease in the advance angle is avoided, and torque shock is reduced.

[0034] The advance angle, duration, retard speed, and retard angle of the ignition timing during the rapid acceleration process are determined by calculations of the electronic control device (5) based on a rapid acceleration ignition timing map. The rapid acceleration ignition timing map is stored in a memory section of the electronic control device (5).

[0035] A throttle position sensor is used as the sudden acceleration operation detection sensor (10) shown in FIG. 1. When it detects that the opening speed of the throttle valve (2) exceeds a predetermined value, the electronic control device (5) determines that a sudden acceleration operation has been performed.

[0036] The flow of control by the electronic control device (5) will now be described. As shown in FIG. 5, in the start preparation process, the engine coolant temperature, the atmospheric pressure, and the intake air temperature are read in step (S1), the cranking opening of the ISC valve (4) is determined in step (S2), the fuel injection amount, fuel injection timing, and ignition timing during cranking are determined in step (S3), the ISC valve (4) is adjusted to the cranking opening in step (S4), and the process proceeds to step (S5), which is the start step of the start process.

[0037] As shown in FIG. 5, in the starting process, in step (S5), it is determined whether or not the key switch (29) is in the starting position (29a) (the determination is repeated until a positive result is obtained). If the result is positive, cranking is started in step (S6). If the result is positive, fuel is injected and the air-fuel mixture is ignited in step (S7). If the engine speed is read in step (S8), it is determined whether or not the engine speed has reached a predetermined cranking end determination value. If the result is positive, cranking is ended in step (S10), and the process proceeds to step (S13), which is the start step of the cranking end process shown in FIG. 4.

[0038] If the determination in step (S9) is negative, then in step (S11) it is determined whether or not the start failure determination time has elapsed, and if so, then in step (S12) cranking is terminated and the process returns to step (S1), which is the start step of the start preparation process, for restart. If the determination in step (S11) is negative, then the process returns to step (S7).

[0039] FIG. 6 is a flowchart of the process after cranking is completed. As shown in FIG. 6, in step (S13), which is the start step of the process after cranking is finished, the position of the throttle valve (2) is read, and in step (S14), it is determined whether or not the throttle valve (2) is in the fully closed position. If the result is affirmative, the process proceeds to step (S15), which is the start step of the fully closed operation process, and if the result is negative, the process proceeds to step (S18), which is the start step of the not-fully closed operation process.

[0040] As shown in FIG. 6, in the totally closed operation process (processing for idling operation, etc.), in step (S15), the engine coolant temperature, atmospheric pressure, intake air temperature, intake pressure, and engine speed are read, and in step (S16), the target idling speed, the idling operation opening of the ISC valve (4), the fuel injection amount, the fuel injection timing, and the ignition timing are determined. In step (S17), the idling operation opening of the ISC valve (4) is adjusted, fuel is injected, the air-fuel mixture is ignited, and the process returns to step (S13), which is the start step of the process after cranking is completed. In the fully closed operation process, the electronic control device (5) performs a rotation speed feedback control to bring the engine rotation speed closer to the idling target rotation speed.

[0041] As shown in FIG. 6, in the non-fully closed operation processing (processing for load operation, etc.), the ISC valve is fully opened in step (S18), and it is determined in step (S19) whether or not a sudden acceleration operation has been performed. If the result is negative, the process proceeds to step (S20), which is the start step of the normal operation processing, and if the result is positive, the process proceeds to step (S23), which is the start step of the sudden acceleration processing shown in FIG. 7.

[0042] As shown in FIG. 6, in the normal operation process, the engine coolant temperature, atmospheric pressure, intake air temperature, intake air pressure, and engine speed are read in step (S20), the fuel injection amount, fuel injection timing, and ignition timing are determined in step (S21), fuel is injected and the air-fuel mixture is ignited in step (S22), and the process returns to step (S13), which is the start step of the process after cranking is completed.

[0043] As shown in FIG. 7, in the rapid acceleration processing, in step (S23), measurement of the duration of the rapid acceleration processing is started, in step (S24), the engine coolant temperature, the atmospheric pressure, the intake air temperature, the intake air pressure, and the engine speed are read, in step (S25), the fuel injection amount and the fuel injection timing are determined, in step (S26), it is determined whether or not this is the first ignition of the rapid acceleration processing, and if the result is affirmative, in step (S27), the ignition timing is determined and this ignition timing is stored, in step (S28), fuel is injected and the air-fuel mixture is ignited, and the process returns to step (S23).

[0044] If the determination in step (S26) is negative, that is, if the ignition is the second or subsequent ignition in the rapid acceleration process, in step (S29) it is determined whether a predetermined retardation waiting time has elapsed since the previous ignition. If the determination is positive, in step (S30) the previous ignition timing stored is read, and the angle to be retarded from the previous ignition timing is read, and in step (S31) the ignition timing is determined and stored. The advance angle of the ignition timing to be determined is a value obtained by subtracting the retard angle from the advance angle of the previous ignition timing, and is brought close to the advance angle of the ignition timing in the normal operation process to be transitioned. A restriction is imposed on the determination in step (S31), and retarding to an advance angle smaller than the ignition timing in the normal operation process to be transitioned is prohibited. Following step (S31), in step (S32), fuel is injected and the mixture is ignited, and in step (S33) it is determined whether the required duration of the rapid acceleration process has elapsed. If the determination is negative, the process returns to step (S23).

[0045] If the determination in step (S29) is negative, that is, if the retard wait time has not elapsed since the previous ignition, the process proceeds to step (S27), where the ignition timing to be determined is the same advance angle as the previous ignition timing.

[0046] If the determination in step (S33) is affirmative, the measurement of the duration of the rapid acceleration process is terminated in step (S34), the measurement value is reset, and the process returns to step (S20), which is the start step of the normal operation process. [Explanation of symbols]

[0047] (5)...Electronic control device, (10)...Sudden acceleration operation detection sensor.

Claims

[Claim 1] The vehicle is provided with a sudden acceleration detection sensor (10), and under the control of an electronic control device (5), when a sudden acceleration operation is not detected, normal driving processing is performed, and when a sudden acceleration operation is detected, the sudden acceleration processing is performed for a required duration, and then the vehicle is shifted to normal driving processing; In the rapid acceleration process, the advance angle of the ignition timing is set to be greater than that in the normal operation process, and is configured to be retarded over time during the required duration of the rapid acceleration process; The engine is provided with a main intake passage (1), a throttle valve (2) in the main intake passage (1), a bypass intake passage (3) that bypasses the throttle valve (2), an ISC valve (4) in the bypass intake passage (3), and an electronic control device (5) that adjusts the opening of the ISC valve (4) to control the engine speed, An engine temperature sensor (6) and an atmospheric pressure sensor (8) are provided. The lower the detected engine temperature, the more the base lower limit value (4b) of the ISC valve opening is increased (4ba) to the fully open side. In the engine medium-high temperature range where the engine temperature exceeds a predetermined value, the base lower limit value (4b) is increased (4ca) toward the fully open side by an increased correction value (4c) based on the detected atmospheric pressure, and in this increased correction (4ca), the increased correction value (4c) is increased (4cb) toward the fully open side as the detected atmospheric pressure becomes lower; 1. A spark ignition engine, comprising: a spark ignition engine configured such that, in a low engine temperature region where the engine temperature is equal to or lower than a predetermined value, increasing correction (4ca) is prohibited (4cc).

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