Engine equipment

Abstract

To appropriately suppress occurrence of knocking in an engine.SOLUTION: An engine device includes an engine equipped with a supercharger having a compressor attached into an intake pipe and outputting power by receiving supply of fuel from a fuel tank, and a control device for controlling ignition timing of the engine with the usage of a leaning value of KCS (knock control system) learning on the basis of occurrence or non-occurrence of knocking in the engine. The control device restricts a load factor of the engine so that the load factor becomes smaller as the learning value is closer to a value on the retard side, and so that the load factor becomes smaller as an engine speed is higher, and / or so that the load factor becomes smaller as an intake temperature of the engine is higher.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] This disclosure relates to an engine device.

Background Art

[0002] Conventionally, as this type of engine device, the reference ignition timing of the engine is set according to the operating state of the engine, the reference ignition timing is corrected to the retard side to suppress knocking, and the target air amount for outputting the target torque to the engine is set according to the reference ignition timing or the ignition timing corrected to the retard side, and the target air amount is limited so as not to exceed a threshold value set according to the operating state, and a device that controls the intake air amount according to the target air amount limited to the threshold value or less has been proposed (for example, see Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In such an engine device, depending on the operating state and fuel properties, knocking may occur even if the ignition timing is retarded to near the misfire limit ignition timing, which is the ignition timing immediately before (slightly on the advanced side) the misfire region where misfire occurs in the engine. In particular, when the engine includes a supercharger and the load factor of the engine increases, such problems are a concern.

[0005] The main object of the engine device of this disclosure is to more appropriately suppress the occurrence of knocking in the engine.

Means for Solving the Problems

[0006] The engine device of this disclosure has taken the following means to achieve the above main object.

[0007] The engine device of this disclosure, An engine system comprising: an engine that has a supercharger with a compressor installed in the intake manifold and outputs power by receiving fuel from a fuel tank; and a control device that controls the ignition timing of the engine using a KCS (Knock control system) learning value based on whether or not knocking occurs in the engine, The control device limits the load ratio of the engine such that the learned value becomes smaller as the angle retardation side increases, and the load ratio becomes smaller as the engine speed increases and / or as the engine intake air temperature increases. This is the gist of it.

[0008] In the engine device of this disclosure, the engine load ratio is limited such that the learned value of KCS learning becomes smaller as the retarded ignition timing value increases, and also decreases as the engine speed increases and / or as the engine intake air temperature increases. By limiting the load ratio in this way, the occurrence of knocking in the engine can be suppressed more effectively. The inventors have confirmed this through experiments and analyses. However, the load ratio may not be limited when the learned value is on the advanced ignition timing side of a predetermined value, when the engine speed is below a predetermined speed, or when the intake air temperature is below a predetermined temperature.

[0009] In the engine device of the present disclosure, a plurality of temperature sensors are arranged in the intake pipe, and the control device may use the detection value of the sensor closest to the combustion chamber of the engine among the plurality of temperature sensors as the intake air temperature.

[0010] In the engine device of the present disclosure, the device includes a knocking sensor for detecting knocking in the engine and an intake air temperature sensor for detecting the intake air temperature, and the control device may set the learned value to the slowest angle value when the knocking sensor is abnormal and set the intake air temperature to the highest temperature when the intake air temperature sensor is abnormal.

[0011] In the engine device of the present disclosure, the control device may set an upper limit load ratio such that the learned value becomes smaller as the ignition timing is retarded, and the rotational speed increases and / or the intake air temperature increases, and set a target load ratio by setting an upper limit guard against the requested load ratio with the upper limit load ratio, thereby controlling the engine. [Brief explanation of the drawing]

[0012] [Figure 1] This is a schematic diagram of a hybrid vehicle 20 equipped with an engine system as an embodiment of the present disclosure. [Figure 2] This is a schematic diagram of the engine 22 installed in the hybrid vehicle 20. [Figure 3] This is an explanatory diagram showing an example of the input and output signals of the engine ECU24 installed in the hybrid vehicle 20. [Figure 4] This flowchart shows an example of a load limit setting routine executed by the engine ECU24. [Figure 5] This is an explanatory diagram showing an example of the relationship between the load factor KL and the ignition timing Ti of engine 22. [Modes for carrying out the invention]

[0013] Embodiments of this disclosure will be described with reference to the drawings. Figure 1 is a schematic diagram of a hybrid vehicle 20 equipped with an engine system as an embodiment of this disclosure. Figure 2 is a schematic diagram of an engine 22 mounted on the hybrid vehicle 20. Figure 3 is an explanatory diagram showing an example of input and output signals of an engine electronic control unit (hereinafter referred to as "engine ECU") 24 mounted on the hybrid vehicle 20.

[0014] As shown in Figure 1, the hybrid vehicle 20 of the embodiment includes an engine 22, an engine ECU 24, a motor 30, an inverter 32, a motor electronic control unit (hereinafter referred to as "motor ECU") 34, a clutch K0, a power transmission device 40, and a hybrid electronic control unit (hereinafter referred to as "HVECU") 70.

[0015] The engine 22 is configured as a multi-cylinder internal combustion engine that outputs power through four strokes: intake, compression, expansion (explosive combustion), and exhaust, using hydrocarbon fuels such as gasoline or diesel from a fuel tank. As shown in Figure 2, the engine 22 has a port injection valve 130 that injects fuel into the intake port and an in-cylinder injection valve 131 that injects fuel into the combustion chamber 133, and can be operated in any of the following modes: port injection mode, in-cylinder injection mode, or shared injection mode. In port injection mode, air cleaned by the air cleaner 122 is drawn into the intake manifold 123, passes through the intercooler 125 and throttle valve 126 located in the intake manifold 123, and then passes through the surge tank 127, intake manifold 128, and intake port 129, while fuel is injected from the port injection valve 130 in the intake port 129 to mix the air and fuel. This air-fuel mixture is drawn into the combustion chamber 133 via the intake valve 132 and explodes and burns due to an electric spark from the spark plug 134. The reciprocating motion of the piston 135, which is pushed down by the energy from the explosive combustion, is then converted into rotational motion of the crankshaft 23. In the in-cylinder injection mode, air is drawn into the combustion chamber 133 in the same way as in the port injection mode, and fuel is injected from the in-cylinder injection valve 131 in one or more stages during the intake stroke and compression stroke, and explodes and burns due to an electric spark from the spark plug 134 to obtain rotational motion of the crankshaft 23. In the shared injection mode, fuel is injected from the port injection valve 130 when air is drawn into the combustion chamber 133, and fuel is also injected from the in-cylinder injection valve 131 in one or more stages during the intake stroke and compression stroke, and explodes and burns due to an electric spark from the spark plug 134 to obtain rotational motion of the crankshaft 23. The exhaust gas discharged from the combustion chamber 133 through the exhaust valve 140, exhaust port 141, and exhaust manifold 142 to the exhaust pipe 143 is discharged to the outside air via a purification device 145. The purification device 145 has a catalyst (three-way catalyst) 145a that purifies harmful components such as carbon monoxide (CO), hydrocarbons (HC), and nitrogen oxides (NOx).

[0016] The engine 22 is equipped with a supercharger 160. The supercharger 160 is configured as a turbocharger and includes a compressor 161, a turbine 162, a connecting shaft 163, a wastegate valve 164, and a blow-off valve 165. The compressor 161 is located upstream of the intercooler 125 in the intake manifold 123. The turbine 162 is located upstream of the purification device 145 in the exhaust manifold 143. The connecting shaft 163 connects the compressor 161 and the turbine 162. The wastegate valve 164 is located in a bypass pipe 144 connecting the upstream and downstream sides of the turbine 162 in the exhaust manifold 143 and is controlled by the engine ECU 24. The blow-off valve 165 is located in a bypass pipe 124 connecting the upstream and downstream sides of the compressor 161 in the intake manifold 123 and is controlled by the engine ECU 24.

[0017] In this supercharger 160, the engine ECU 24 adjusts the opening of the wastegate valve 164, thereby adjusting the distribution ratio between the amount of exhaust flowing through the bypass pipe 144 and the amount of exhaust flowing through the turbine 162. This adjusts the rotational driving force of the turbine 162, the amount of compressed air from the compressor 161, and the boost pressure (intake pressure) of the engine 22. Specifically, the distribution ratio is adjusted such that the smaller the opening of the wastegate valve 164, the less exhaust flows through the bypass pipe 144 and the more exhaust flows through the turbine 162. When the wastegate valve 164 is fully open, the engine 22 can operate in the same way as a naturally aspirated engine without the supercharger 160.

[0018] Furthermore, in the supercharger 160, when the pressure downstream of the compressor 161 in the intake manifold 123 is somewhat higher than the pressure upstream, the blow-off valve 165 is opened, thereby releasing the excess pressure downstream of the compressor 161. Alternatively, the blow-off valve 165 may be configured as a check valve that opens when the pressure downstream of the compressor 161 in the intake manifold 123 becomes somewhat higher than the pressure upstream, instead of being a valve controlled by the engine ECU 24.

[0019] The engine ECU 24 includes a microcomputer with a CPU, ROM, RAM, flash memory, input / output ports, and communication ports, as well as various drive circuits and various logic ICs. As shown in Figure 3, the engine ECU 24 receives inputs such as the crank angle θcr from the crank position sensor 150 which detects the rotational position of the crankshaft 23 of the engine 22, the coolant temperature Tw from the coolant temperature sensor 151 which detects the temperature of the coolant in the engine 22, and the oil temperature To from the oil temperature sensor 152 which detects the temperature of the engine oil. The engine ECU 24 also receives inputs of the throttle opening TH from the throttle position sensor 126a which detects the opening degree of the throttle valve 126. The engine ECU 24 also receives inputs of the cam angles θci and θco from the cam position sensor 153 which detects the rotational position of the intake camshaft that opens and closes the intake valve 132 and the rotational position of the exhaust camshaft that opens and closes the exhaust valve 140. The engine ECU 24 also receives input from the intake air volume Qa from the airflow meter 123a, which is installed upstream of the compressor 161 in the intake manifold 123, and the first intake air temperature Ta1 from the first intake air temperature sensor 123t, which is installed upstream of the compressor 161 in the intake manifold 123. The engine ECU 24 also receives input from the intake pressure (pressure in front of the compressor) Pa1 from the first pressure sensor 123b, which is installed upstream of the compressor 161 in the intake manifold 123, and the boost pressure (pressure behind the compressor) Pa2 from the second pressure sensor 123c, which is installed between the compressor 161 and the intercooler 125 in the intake manifold 123. The engine ECU 24 also receives input from the surge pressure (throttle pressure) Pa3 from the third pressure sensor 127a attached to the surge tank 127, the second intake air temperature Ta2 from the second intake air temperature sensor 127t attached to the surge tank 127, and the third intake air temperature Ta3 from the third intake air temperature sensor 128t attached to the intake manifold 128. The engine ECU 24 also receives input from the front air-fuel ratio AF1 from the front air-fuel ratio sensor 146a attached between the turbine 162 of the supercharger 160 and the purification device 145 in the exhaust pipe 143, and the rear air-fuel ratio AF2 from the rear air-fuel ratio sensor 146b attached downstream of the purification device 145 in the exhaust pipe 143.The engine ECU 24 is also input with a knock signal Ks from a knock sensor 154 that is attached to the cylinder block and detects vibrations generated with the occurrence of knocking.

[0020] The engine ECU 24 outputs, for example, a control signal to the throttle valve 126, a control signal to the port injection valve 130, a control signal to the in-cylinder injection valve 131, and a control signal to the ignition plug 134. The engine ECU 24 also outputs a control signal to the wastegate valve 164 and a control signal to the blow-off valve 165. The engine ECU 24 calculates the rotational speed Ne of the engine 22 based on the crank angle θcr of the engine 22 from the crank position sensor 150. The engine ECU 24 calculates a load factor KL (the ratio of the volume of air actually inhaled in one cycle to the stroke volume per cycle of the engine 22) based on the intake air volume Qa from the air flow meter 123a and the rotational speed Ne of the engine 22.

[0021] As shown in FIG. 1, a starter motor 25 for cranking the engine 22 and an alternator 26 that generates electricity using the power from the engine 22 are connected to the crankshaft 23 of the engine 22. The starter motor 25 and the alternator 26 are connected to the low-voltage power line 63 together with the low-voltage battery 62 and are controlled by the HV ECU 70.

[0022] The motor 30 is configured as a synchronous generator motor and has a rotor in which permanent magnets are embedded in the rotor core and a stator in which three-phase coils are wound around the stator core. A rotary shaft 31 to which the rotor of the motor 30 is fixed is connected to the crankshaft 23 of the engine 22 via a clutch K0 and is also connected to the input shaft 41 of the power transmission device 40. The inverter 32 is used to drive the motor 30. Further, the inverter 32 is connected to the high-voltage power line 61 together with the high-voltage battery 60. The motor 30 is rotationally driven by switching control of a plurality of switching elements of the inverter 32 by the motor ECU 34.

[0023] The motor ECU 34, like the engine ECU 24, is equipped with a microcomputer and other components. The motor ECU 34 receives, for example, the rotational position θmg from the rotational position sensor 30a, which detects the rotational position of the rotor (rotating shaft 31) of the motor 30, and the phase currents Iu and Iv from the current sensors, which detect the phase currents of each phase of the motor 30. The motor ECU 34 outputs, for example, control signals to the inverter 32. The motor ECU 34 calculates the rotational speed Nmg of the motor 30 based on the rotational position θmg of the rotor (rotating shaft 31) of the motor 30 as detected by the rotational position sensor 30a.

[0024] Clutch K0 is configured, for example, as a hydraulically driven friction clutch, controlled by HVECU 70, and connects and disconnects the crankshaft 23 of engine 22 from the rotating shaft 31 of motor 30.

[0025] The power transmission device 40 comprises a torque converter 43 and an automatic transmission 45. The torque converter 43 is configured as a general fluid transmission device and transmits power from the input shaft 41 connected to the rotating shaft 31 of the motor 30 to the intermediate shaft 44, which is the input shaft of the automatic transmission 45, with amplified torque, or transmits the torque directly without amplification. The automatic transmission 45 has an intermediate shaft 44, an output shaft 42 connected to the drive wheel 49 via a differential gear 48, at least one planetary gear mechanism, and a plurality of hydraulically driven friction engagement elements (clutch, brake). The automatic transmission 45 transmits power between the intermediate shaft 44 and the output shaft 42 by selectively engaging some of the plurality of friction engagement elements to form a plurality of forward and reverse gears. The clutch K0 and the automatic transmission 45 are supplied with hydraulically regulated hydraulic fluid from a mechanical oil pump or an electric oil pump by a hydraulic control device (not shown). The automatic transmission 45 may also be, for example, a continuously variable transmission (CVT) or a dual-clutch transmission.

[0026] The high-voltage battery 60 is configured as, for example, a lithium-ion secondary battery or nickel-metal hydride secondary battery with a rated voltage of several hundred volts, and is connected to the high-voltage power line 61 together with the inverter 32. The low-voltage battery 62 is configured as, for example, a lithium-ion secondary battery or lead-acid battery with a rated voltage of 12V or 14V, and is connected to the low-voltage power line 63 together with the starter motor 25 and alternator 26. The DC / DC converter 64 is connected to the high-voltage power line 61 and the low-voltage power line 63. This DC / DC converter 64 steps down the power from the high-voltage power line 61 and supplies it to the low-voltage power line 63.

[0027] The HVECU70, like the engine ECU24, is equipped with a microcomputer and other components. The HVECU70 receives, for example, the rotational speed Nin from the rotational speed sensor 41a attached to the input shaft 41 of the power transmission device 40, the rotational speed Nmi from the rotational speed sensor 44a attached to the intermediate shaft 44 of the power transmission device 40, and the rotational speed Nout from the rotational speed sensor 42a attached to the output shaft 42 of the power transmission device 40. The HVECU70 also receives the voltage Vb1 from the voltage sensor attached between the terminals of the high-voltage battery 60, the current Ib1 from the current sensor attached to the output terminal of the high-voltage battery 60, the voltage Vb2 from the voltage sensor attached between the terminals of the low-voltage battery 62, and the current Ib2 from the current sensor attached to the output terminal of the low-voltage battery 62. The HVECU70 also receives inputs from the ignition switch 80, the shift position SP from the shift position sensor 82 which detects the operating position of the shift lever 81, the accelerator opening Acc from the accelerator pedal position sensor 84 which detects the amount the accelerator pedal 83 is pressed, the brake pedal position BP from the brake pedal position sensor 86 which detects the amount the brake pedal 85 is pressed, and the vehicle speed V from the vehicle speed sensor 87.

[0028] HVECU70 outputs control signals to, for example, the starter motor 25, the alternator 26, the clutch K0 and the power transmission device 40 (hydraulic control device), and the DC / DC converter 64. HVECU70 communicates with the engine ECU24 and the motor ECU34. HVECU70 calculates the rotational speed ratio Gt of the power transmission device 40 by dividing the rotational speed Nin of the input shaft 41 of the power transmission device 40 from the rotational speed sensor 41a by the rotational speed Nout of the output shaft 42 of the power transmission device 40 from the rotational speed sensor 42a.

[0029] In the hybrid vehicle 20 of this embodiment, the HVECU 70, engine ECU 24, and motor ECU 34 cooperate to control the engine 22, clutch K0, motor 30, and power transmission device 40 so that the vehicle can run in hybrid driving mode (HV driving mode) or electric driving mode (EV driving mode). Here, HV driving mode is a mode in which the vehicle runs using the power of the engine 22 with the clutch K0 engaged, and EV driving mode is a mode in which the vehicle runs without using the power of the engine 22 with the clutch K0 disengaged.

[0030] In controlling the power transmission system 40 in HV driving mode and EV driving mode, the HVECU 70 sets the target gear position Gs* of the automatic transmission 45 based on the accelerator opening Acc and vehicle speed V, and controls the automatic transmission 45 so that the gear position Gs of the automatic transmission 45 becomes the target gear position Gs*. In controlling the engine 22 and motor 30 in HV driving mode, the HVECU 70 sets the required torque Tin* of the input shaft 41 of the power transmission system 40 based on the accelerator opening Acc, vehicle speed V and the rotational speed ratio Gt of the power transmission system 40, sets the target torque Te* of the engine 22 and the torque command Tm* of the motor 30 so that the required torque Tin* is output to the input shaft 41, and transmits the target torque Te* to the engine ECU 24 and the torque command Tm* to the motor ECU 34. The engine ECU 24 controls the operation of the engine 22 so that the engine 22 is operated at the target torque Te*. The motor ECU 34 controls the switching of multiple switching elements of the inverter 32 so that the motor 30 is driven by the torque command Tm*. The control of the engine 22 and motor 30 in EV driving mode is not central to the present invention, so a detailed explanation is omitted.

[0031] The details of the operation control of engine 22 will be explained. The engine ECU 24 sets the required load ratio KLrq based on the target torque Te* of engine 22, sets the target load ratio KL* by setting the upper limit load ratio KLmax to the set required load ratio KLrq, and performs intake air volume control, fuel injection control, ignition control, and supercharging control based on the target load ratio KL*. The method for setting the upper limit load ratio KLmax will be described later. In intake air volume control controls the opening degree of the throttle valve 126. Fuel injection control controls fuel injection from the port injection valve 130 and fuel injection from the in-cylinder injection valve 131. Ignition control controls the ignition timing of the spark plug 134. Supercharging control controls the opening degree of the wastegate valve 164.

[0032] This section explains the details of ignition control. In ignition control, the basic ignition timing Tibs and the misfire limit ignition timing Tifc are first set based on the rotational speed Ne and load factor KL. Here, the basic ignition timing Tibs can be set to the ignition timing that maximizes the output torque of the engine 22 (MBT: Minimum spark advance for Best Torque). The misfire limit ignition timing Tifc is determined by experimentation and analysis as the ignition timing just before (slightly advanced) the misfire region in which misfires occur in the engine 22. Once the basic ignition timing Tibs and the misfire limit ignition timing Tifc are set, the target ignition timing Ti* is set by adding a learned value (correction value) α to the basic ignition timing Tibs, within the range where the misfire limit ignition timing Tifc is the retardedest angle, and the spark plug 134 is controlled so that ignition occurs at the target ignition timing Ti*. The learned value α is set for each region divided by rotational speed Ne and load factor KL through KCS (Knock control system) learning. In KCS learning, for each region, if it is determined that knocking has not occurred based on the knock signal Ks from the knock sensor 154, the learned value α is updated to advance the ignition timing (to make the ignition timing earlier), and if it is determined that knocking has occurred, the learned value α is updated to retard the ignition timing (to make the ignition timing later).

[0033] Next, the operation of the engine system in the hybrid vehicle 20 of the embodiment, in particular the process of setting the upper load ratio KLmax, will be described. Figure 4 is a flowchart showing an example of an upper load ratio setting routine executed by the engine ECU 24. This routine is executed repeatedly while the engine 22 is running.

[0034] When the upper limit load rate setting routine in Figure 2 is executed, the engine ECU 24 first inputs the learned value α, rotational speed Ne, and intake air temperature Ta (step S100). Here, the learned value α is the value set (updated) by the KCS learning described above. The rotational speed Ne is the value calculated based on the crank angle θcr. The intake air temperature Ta is the value detected by the intake air temperature sensor closest to the combustion chamber 133 among the first intake air temperature sensor 123t, the second intake air temperature sensor 127t, and the third intake air temperature sensor 128t, specifically the third intake air temperature Ta3 detected by the third intake air temperature sensor 128t.

[0035] Once the data is input, the upper limit load ratio KLmax is set based on the input learned value α, rotational speed Ne, and intake air temperature Ta (step S110), and the routine terminates. Here, the upper limit load ratio KLmax can be set, for example, by applying the learned value α, rotational speed Ne, and intake air temperature Ta to an upper limit load ratio map that has been predetermined by experiment, analysis, or machine learning as the relationship between the learned value α, rotational speed Ne, intake air temperature Ta, and upper limit load ratio KLmax. The upper limit load ratio map is set such that the upper limit load ratio KLmax decreases as the learned value α is retarded, as the rotational speed Ne is large, and as the intake air temperature Ta is high. Note that the load ratio may not be limited when the learned value α is advanced beyond the threshold αref, when the rotational speed Ne is less than the threshold Neref, or when the intake air temperature Ta is less than the threshold Taref. The reason for setting the upper limit load ratio KLmax in this way is explained below.

[0036] Figure 5 is an explanatory diagram showing an example of the analysis results regarding the relationship between the load factor KL and the ignition timing of engine 22 at a certain rotational speed Ne and a certain intake air temperature Ta. In the figure, the solid line shows the knocking ignition timing Tik for each fuel octane rating, and the dashed line shows the misfire limit ignition timing Tifc. The knocking ignition timing Tik is the ignition timing just before (slightly retarded) the knocking region in engine 22 where knocking occurs. As shown in the figure, the knocking ignition timing Tik is retarded as the load factor KL increases and the fuel octane rating decreases. Also, the misfire limit ignition timing Tifc is advanced as the load factor KL increases. Therefore, the range from the misfire limit ignition timing Tifc to the knocking ignition timing Tik (the ignition timing range in which knocking and misfires can be sufficiently suppressed) becomes narrower as the load factor KL increases and as the fuel octane rating decreases. The inventors confirmed that the lower the fuel octane rating and the higher the load factor KL, the more likely knocking is to occur even when the ignition timing is retarded to near the misfire limit ignition timing Tifc. Separately, the inventors also confirmed through experiments and analyses that the lower the fuel octane rating, the more likely the KCS learning value α is to be on the retarded side. Based on these findings, in the embodiment, the upper limit load factor KLmax is set such that the learning value α of KCS learning becomes smaller as the retarded value increases. Furthermore, the inventors also confirmed through experiments and analyses that the higher the load factor KL, the greater the rotational speed Ne, and the higher the intake air temperature Ta, the more likely knocking is to occur even when the ignition timing is retarded to near the misfire limit ignition timing Tifc. Based on these findings, in the embodiment, the upper limit load factor KLmax is set such that it becomes smaller as the rotational speed Ne increases and as the intake air temperature Ta increases. By setting the upper limit load ratio KLmax such that it decreases as the fuel octane number decreases (as the KCS learning value α is on the retard side), as the rotational speed Ne increases, and as the intake air temperature Ta increases, knocking in engine 22 can be suppressed more effectively.

[0037] In the engine system installed in the hybrid vehicle 20 of this embodiment described above, the engine ECU 24 sets the upper limit load ratio KLmax based on the KCS learning value α, the rotational speed Ne, and the intake air temperature Ta. Specifically, the upper limit load ratio KLmax is set such that the more retarded the learning value α is, the smaller the upper limit load ratio KLmax becomes, the larger the rotational speed Ne is, and the larger the intake air temperature Ta is. Then, the requested load ratio KLrq is capped by the upper limit load ratio KLmax to set the target load ratio KL*, and intake air volume control, fuel injection control, ignition control, and supercharging control are performed based on the target load ratio KL*. This makes it possible to more appropriately suppress the occurrence of knocking in the engine 22.

[0038] In the embodiment described above, the engine ECU 24 sets the upper limit load ratio KLmax based on the KCS learning value α, rotational speed Ne, and intake air temperature Ta. However, instead, the upper limit load ratio KLmax may be set based on the learning value α and rotational speed Ne without using the intake air temperature Ta. Alternatively, the upper limit load ratio KLmax may be set based on the learning value α and intake air temperature Ta without using the rotational speed Ne.

[0039] In the embodiment described above, the engine ECU 24 sets the upper limit load ratio KLmax such that the upper limit load ratio KLmax decreases as the learned value α of KCS learning moves toward the retarded angle side. However, in the event of a malfunction of the knock sensor 154, the retarded angle value within the assumed range may be used as the learned value α. This would further suppress the occurrence of knocking in the engine 22 when the knock sensor 154 malfunctions.

[0040] In the embodiment described above, the engine ECU 24 sets the upper limit load ratio KLmax such that the upper limit load ratio KLmax decreases as the intake air temperature Ta increases. However, in the event of a malfunction of the third intake air temperature sensor 128t, the highest temperature within the assumed range may be used as the intake air temperature Ta. This would further suppress the occurrence of knocking in the engine 22 when the third intake air temperature sensor 128t malfunctions.

[0041] In the embodiment described above, the system includes a second intake air temperature sensor 127t attached to the surge tank 127 and a third intake air temperature sensor 128t attached to the intake manifold 128. However, it may also include only one of these sensors.

[0042] In the embodiment described above, the engine 22 is equipped with a port injection valve 130 and an in-cylinder injection valve 131. However, it may be equipped with only one of these.

[0043] In the embodiment described above, the supercharger 160 is configured as a turbocharger in which a compressor 161 located in the intake pipe 123 and a turbine 162 located in the exhaust pipe 143 are connected via a connecting shaft 163. However, instead, a compressor driven by the engine 22 or a motor may be configured as a supercharger located in the intake pipe 123.

[0044] In the embodiment described above, the system includes an engine ECU 24, a motor ECU 34, and an HVECU 70. However, at least two of these may be configured as a single unit.

[0045] In the embodiment described above, the engine system is configured to be mounted on a hybrid vehicle 20 equipped with an engine 22 and a motor 30, but it is not limited to this. For example, it may be configured to be mounted on a vehicle that has an engine but no motor. It may also be configured to be mounted on a moving object other than a vehicle, or on a stationary construction facility or the like.

[0046] The correspondence between the main elements of the embodiment and the main elements of the invention described in the section on means for solving the problem will be explained. In the embodiment, engine 22 corresponds to "engine," and engine ECU 24 corresponds to "control device."

[0047] Furthermore, the correspondence between the main elements of the embodiment and the main elements of the invention described in the section on means for solving the problem is merely an example to specifically explain the form in which the embodiment implements the invention described in the section on means for solving the problem, and does not limit the elements of the invention described in the section on means for solving the problem. In other words, the interpretation of the invention described in the section on means for solving the problem should be based on the description in that section, and the embodiment is merely one specific example of the invention described in the section on means for solving the problem.

[0048] While embodiments for implementing this disclosure have been described above, this disclosure is not limited in any way to these embodiments, and can of course be implemented in various forms without departing from the gist of this disclosure. [Industrial applicability]

[0049] This disclosure can be used in industries such as the manufacturing of engine equipment. [Explanation of symbols]

[0050] 20 Hybrid vehicle, 22 Engine, 23 Crankshaft, 24 Engine ECU, 25 Starter motor, 26 Alternator, 30 Motor, 30a Rotation position sensor, 31 Rotating shaft, 32 Inverter, 34 Motor ECU, 40 Power transmission system, 41 Input shaft, 41a Rotation speed sensor, 42 Output shaft, 42a Rotation speed sensor, 43 Torque converter, 44 Intermediate shaft, 44a Rotation speed sensor, 45 Automatic transmission, 48 Differential gear, 49 Drive wheels, 60 High-voltage battery, 61 High-voltage side power line, 62 Low-voltage battery, 63 Low-voltage side power line, 64 DC / DC converter, 70 HVECU, 80 Ignition switch, 81 Shift lever, 82 Shift position sensor, 83 Accelerator pedal, 84 Accelerator pedal position sensor, 85 Brake pedal, 86 Brake pedal position sensor, 87 Vehicle speed sensor, 122 Air cleaner, 123 Intake pipe, 123a Airflow meter, 123b First pressure sensor, 123c Second pressure sensor, 123t First intake air temperature sensor, 124 Bypass pipe, 125 Intercooler, 126 Throttle valve, 126a Throttle position sensor, 127 Surge tank, 127a Third pressure sensor, 127t Second intake air temperature sensor, 128 Intake manifold, 128t Third intake air temperature sensor, 129 Intake port, 130 Port injection valve, 131 In-cylinder injection valve, 132 Intake valve, 133 Combustion chamber, 134 Spark plug, 135 Piston, 140 Exhaust valve, 141 Exhaust port, 142 Exhaust manifold, 143 Exhaust pipe, 144 Bypass pipe, 145 Purification device, 146a Front air-fuel ratio sensor, 146b Rear air-fuel ratio sensor, 150 Crank position sensor, 151 Water temperature sensor, 152 Oil temperature sensor, 153 Cam position sensor, 154 Knock sensor, 160 Supercharger, 161 Compressor, 162 Turbine, 163 Connecting shaft, 164 Wastegate valve, 165 Blow-off valve.

Claims

1. An engine system comprising: an engine that has a supercharger with a compressor installed in the intake manifold and outputs power by receiving fuel from a fuel tank; and a control device that controls the ignition timing of the engine using a KCS (Knock control system) learning value based on whether or not knocking occurs in the engine, The control device limits the upper limit of the engine load ratio such that the learned value becomes smaller as the angle retardation side increases, the engine speed increases, and the engine intake air temperature increases. Engine unit.

2. The engine device according to claim 1, Multiple temperature sensors are arranged in the intake pipe. The control device uses the detection value of the sensor closest to the combustion chamber of the engine among the plurality of temperature sensors as the intake air temperature. Engine unit.

3. An engine device according to claim 1 or 2, The control device sets an upper limit load ratio such that the learned value becomes smaller as the ignition timing is retarded, and the rotational speed increases and / or the intake air temperature increases, and controls the engine by setting a target load ratio by using the upper limit load ratio as an upper limit guard against the requested load ratio. Engine unit.

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