Vehicle control system

Abstract

The objective is to provide a vehicle control device that can enhance sportiness while suppressing the occurrence of vehicle shocks. [Solution] A control device for a vehicle equipped with an engine having a fuel injector, comprising: a normal start control unit that performs normal start control to start the engine by controlling the amount of fuel injected from the fuel injector to a normal start injection amount; and an upward start control unit that starts the engine by controlling the amount of fuel injected to an upward start injection amount greater than the normal start injection amount so that the upward rotational speed at the time of engine startup is greater than that of the normal start control, and after the engine has started, performs upward start control to gradually change the amount of fuel injected from the upward start injection amount to a required injection amount corresponding to the required driving force to the engine.

Description

Technical Field

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[0001] The present invention relates to a control device for a vehicle.

Background Art

[0002] There is a vehicle equipped with an engine (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

Means for Solving the Problems

[0007] The aforementioned interruption request may also include a request to start the vehicle.

[0008] The aforementioned interruption request may also occur if it is diagnosed that there is an abnormality in the engine.

[0009] The blow-up starting control unit may increase the blow-up starting injection amount as the temperature of the engine's cooling water decreases. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a vehicle control device that can enhance sportiness while suppressing the occurrence of shocks in the vehicle. [Brief explanation of the drawing]

[0011] [Figure 1] This is a schematic diagram of the engine's configuration. [Figure 2] This is a flowchart illustrating engine start control. [Figure 3] This is a timing chart illustrating engine start control. [Figure 4] This timing chart illustrates a case where the engine switches from blow-up starting control to normal starting control. [Figure 5] This is an example diagram of a map that defines the initial values ​​for the increased blow-up amount and the normal increase amount, depending on the engine coolant temperature. [Modes for carrying out the invention]

[0012] [Engine Overview] Figure 1 is a schematic diagram of the engine 10 mounted on vehicle 1. Vehicle 1 includes the engine 10, drive wheels 13 to which the power of the engine 10 is transmitted via a shaft, and a starter 16 for starting the engine 10. The engine 10 is a gasoline engine with multiple cylinders, but it may also be a diesel engine or a hydrogen engine. A transmission and differential gear (not shown) are provided in the power transmission path from the engine 10 to the drive wheels 13.

[0013] The engine 10 includes a cylinder block 30, a cylinder head 32, a piston 33, a connecting rod 34, a crankshaft 35, an intake passage 36, an intake valve 36v, an exhaust passage 37, and an exhaust valve 37v.

[0014] The cylinder block 30 is provided with a cylindrical bore 31. The piston 33 is housed within the bore 31 so as to be able to reciprocate. The combustion chamber C is defined by the walls of the bore 31, the lower surface of the cylinder head 32, and the top surface of the piston 33. The volume of the combustion chamber C increases or decreases as the piston 33 reciprocates.

[0015] The crankshaft 35, which is the output shaft of the engine 10, is connected via a connecting rod 34. The connecting rod 34 and the crankshaft 35 convert the reciprocating motion of the piston 33 into the rotational motion of the crankshaft 35. The engine 10 is equipped with the crank angle sensor 62 described above.

[0016] The intake passage 36 is connected to the combustion chamber C via an intake valve 36v. The exhaust passage 37 is connected to the combustion chamber C via an exhaust valve 37v. The intake passage 36 is provided with the airflow meter 63 described above.

[0017] The cylinder block 30 is provided with an in-cylinder injection valve 41D that injects fuel directly into the combustion chamber C. The intake passage 36 is provided with a port injection valve 41P that injects fuel toward the intake port. The cylinder head 32 is provided with a spark plug 42 that ignites the mixture of intake air and fuel introduced into the combustion chamber C. The in-cylinder injection valve 41D and the port injection valve 41P are examples of fuel injection valves.

[0018] The exhaust passage 37 is equipped with a three-way catalytic converter 43 and a GPF (Gasoline Particulate Filter) 44. The three-way catalytic converter 43 contains catalytic metal, has oxygen storage capacity, and purifies NOx, HC, and CO. The GPF 44 is a porous ceramic structure that captures exhaust particulate matter (hereinafter referred to as PM (Particulate Matter)) in the exhaust gas. The GPF 44 is an example of a filter. For example, if the engine 10 is a diesel engine, a DPF (Diesel Particulate Filter) is provided instead of the GPF 44.

[0019] The vehicle 1 is provided with an ECU (Electronic Control Unit) 50. The ECU 50 is an electronic control unit including an arithmetic processing circuit that performs various arithmetic processes related to the running control of the vehicle, and a memory in which control programs and data are stored. The ECU 50 is an example of a control device of the vehicle 1, and specifically, functionally realizes a normal start control unit and a blow-up start control unit which will be described later.

[0020] The following sensors are connected to the ECU 50: a crank angle sensor 62, an air flow meter 63, a water temperature sensor 66, an atmospheric pressure sensor 67, a shift position sensor 68, and an accelerator opening sensor 69. The crank angle sensor 62 detects the rotational speed of the crankshaft of the engine 10. The air flow meter 63 detects the intake air amount introduced into the engine 10. The water temperature sensor 66 detects the temperature of the cooling water that cools the engine 10. The atmospheric pressure sensor 67 detects the atmospheric pressure around the vehicle 1. The shift position sensor 68 detects whether the position of the shift lever is in the P range position, R range position, N range position, or D range position. The accelerator opening sensor 69 detects the accelerator opening which is the operation amount of the accelerator pedal.

[0021] Based on the detection signals of the above-described sensors, the ECU 50 controls the drive of the engine 10 by controlling the opening of the throttle valve 40, the fuel injection amounts of the in-cylinder injection valve 41D and the port injection valve 41P, the ignition timing by the ignition plug 42, etc.

[0022] [Engine Start Control] Figure 2 is a flowchart exemplifying engine start control. This control is repeatedly executed while the ignition is on. The ECU 50 determines whether there is a start request for the engine 10 (step S1). A start request for the engine 10 is requested, for example, when the ignition is switched from off to on, or when the restart condition after automatic stop is satisfied. If the result in step S1 is No, this control ends.

[0023] If the answer in step S1 is Yes, the ECU 50 determines whether or not there is a request for a high-rev start (step S2). A high-rev start request is made, for example, when the temperature of the engine 10's coolant is above a predetermined temperature and the atmospheric pressure of the vehicle 1 is above a predetermined value. As will be explained in more detail later, in high-rev start control, the rotational speed of the engine 10 at startup is controlled to be high, so it is preferable that this be performed under conditions where the starting performance of the engine 10 is ensured and the deterioration of exhaust emissions is suppressed. In addition, for example, if the vehicle 1 can switch the driving mode to eco mode, normal mode, or sport mode and sport mode is selected, it may be considered that there is a high-rev start request.

[0024] If the answer in step S2 is No, the ECU 50 performs normal start control (step S3). In normal start control, the starter 16 starts cranking the engine 10, a predetermined normal start injection amount of fuel (total injection amount of fuel) is injected from at least one of the in-cylinder injection valve 41D and the port injection valve 41P, and the opening of the throttle valve 40 is controlled to the closed side. Specifically, the in-cylinder injection ratio, which is the ratio of the in-cylinder injection amount to the total fuel injection amount, and the port injection ratio, which is the ratio of the port injection amount to the total fuel injection amount, are adjusted based on the temperature of the engine 10's coolant and the temperature of the three-way catalytic converter 43. In normal start control, after the engine 10 starts, the fuel injection amount is gradually changed from the normal start injection amount to the required injection amount according to the required driving force for the engine 10. The required injection amount here is, for example, the fuel injection amount to control the engine 10 to an idle state when the accelerator opening is zero, and the fuel injection amount to realize the driving force of the engine 10 according to the accelerator opening when the accelerator is on. Step S3 is an example of the processing performed by the normal start control unit.

[0025] If the answer in step S2 is Yes, the ECU 50 executes rev-up start control (step S4). In rev-up start control, the starter 16 starts cranking the engine 10, a predetermined amount of rev-up start fuel is injected only from the in-cylinder injector 41D, and the opening of the throttle valve 40 is controlled to the open side. As a result, in rev-up start control, the rev-up speed of the engine 10 at startup is higher than in normal start control. This enhances the sporty feel of the vehicle 1. In addition, the injection of fuel from the in-cylinder injector 41D suppresses the amount of fuel adhering to the intake port, thereby suppressing deterioration of exhaust emissions. Note that injection from the in-cylinder injector 41D occurs once per combustion cycle. Also, the rev-up start injection amount is greater than the normal start injection amount. Step S4 is an example of the process executed by the rev-up start control unit.

[0026] Even with the upward starting control, after the engine 10 starts, the fuel injection amount is gradually changed from the upward starting injection amount to the required injection amount corresponding to the required driving force for the engine 10. This suppresses the occurrence of shocks to the vehicle 1 that may occur if the fuel injection amount is changed abruptly from the upward starting injection amount to the required injection amount.

[0027] Next, the ECU 50 determines whether there is an interruption request while the rev-up start control is being executed and before the gradual change begins (step S5). An interruption request is, for example, when there is a request to start the vehicle 1, or when an abnormality is diagnosed in the engine 10. A start request is made, for example, when the shift position of the automatic transmission is set to the D range position or R range position and the accelerator is operated. An abnormality diagnosis of the engine 10 is, for example, an abnormality diagnosis of equipment related to fuel injection. For example, an abnormality in the sensor that detects the pressure of the fuel supplied to the in-cylinder injector 41D, or an abnormality in fuel leakage from the in-cylinder injector 41D, etc. Other known abnormality diagnoses may also be used.

[0028] If the answer in step S5 is Yes, the ECU 50 switches from rev-up start control to normal start control (step S6). If there is an interruption request as described above, for example, a start request, the rev-up start control may increase the engine speed, potentially causing excessive acceleration when the vehicle 1 starts. Also, if an abnormality in the engine 10 is diagnosed, the rev-up start control may reduce the starting performance of the engine 10. In this embodiment, if an interruption request is made while rev-up start control is being executed but before the start of gradual change, switching from rev-up start control to normal start control can prevent excessive acceleration when the vehicle 1 starts and reduce the starting performance of the engine 10. Step S6 is an example of processing performed by the normal start control unit and the rev-up start control unit.

[0029] Figure 3 is a timing chart illustrating engine start control. Figure 3 shows the changes in engine speed and fuel injection amount increase for both normal start control and rev-up start control when the accelerator is off. In Figure 3, the dotted line represents the normal increase (engine speed and fuel injection amount increase) in normal start control, while the solid line represents the rev-up increase (engine speed and fuel injection amount increase) in rev-up start control. Here, the increase refers to the injection amount added to the basic injection amount used in these start controls. Therefore, the injection amount obtained by adding the normal increase to the basic injection amount is the normal start injection amount mentioned above. Similarly, the injection amount obtained by adding the rev-up increase to the basic injection amount is the rev-up start injection amount mentioned above. The rev-up increase is greater than the normal increase. Since Figure 3 shows the case when the accelerator is off, the basic injection amount corresponds to the idle injection amount necessary for engine 10 to maintain idle operation.

[0030] First, let's explain the normal starting control. When the starter 16 starts cranking the engine 10, fuel injection begins with a normal starting injection amount, which is the basic injection amount plus a normal increase (time t1), and the normal increase is kept constant for a predetermined period. After that, when the engine speed reaches a starting determination speed, which is considered to be the starting speed of the engine 10, the fuel injection amount begins to gradually change from the normal starting injection amount to the idle injection amount (time t2). The idle injection amount here corresponds to the required injection amount according to the required driving force for the engine 10 in the accelerator-off state. As a result, the normal increase gradually decreases to zero (time t3).

[0031] First, let's explain the upward starting control. When the starter 16 starts cranking the engine 10, fuel injection begins with an upward starting injection amount, which is the basic injection amount plus an upward boost amount (time t1), and the upward boost amount is kept constant for a predetermined period. After that, when the engine speed exceeds the starting judgment speed, the fuel injection amount begins to gradually change from the upward starting injection amount to the idle injection amount (time t2). As a result, the upward boost amount gradually decreases to zero (time t3). This gradual change from the upward starting injection amount to the idle injection amount suppresses the occurrence of shocks in the vehicle 1.

[0032] In reality, with upward starting control, the engine speed reaches the starting threshold earlier than with normal starting control. However, for ease of understanding, Figure 3 shows the engine speed reaching the starting threshold at the same time. Also, although the example in Figure 3 describes a case where the gradual change is performed immediately after the engine speed reaches the starting threshold, the gradual change may be started a predetermined time after the engine speed reaches the starting threshold. Preferably, the gradual change is started between the time the engine speed reaches the starting threshold and the time the engine speed begins to decrease.

[0033] Next, we will explain the switching from boost start control to normal start control. Figure 4 is a timing chart illustrating a case where the system switches from boost start control to normal start control. Figure 4 shows the changes in engine speed and fuel injection amount increase when boost start control is being executed and an interruption request due to an abnormality diagnosis of the engine 10 occurs before the gradual change begins. Engine 10 starts cranking and fuel injection at the boost start injection amount begins (time t1). After that, if an interruption request occurs, the system switches from the boost increase to the normal increase (time t12). That is, the fuel injection amount switches from the boost start injection amount to the normal start injection amount, and the system switches from boost start control to normal start control. After that, a gradual change from the normal start injection amount to the idle injection amount begins (time t2), and the normal increase becomes zero (time t3). In this way, if an interruption request occurs before the gradual change begins, the system switches to normal start control, and the decrease in engine 10's starting ability is suppressed. Furthermore, since the injection amount can be switched from the boost-start injection amount to the normal-start injection amount before the engine 10 is started, the occurrence of shocks to the vehicle 1 due to fluctuations in the air-fuel ratio is also suppressed.

[0034] If an interruption request is made after the start of gradual change while the boost start control is in operation, the gradual change from the boost start injection amount to the requested injection amount will continue. For example, in this case, if the system switches from boost start control to normal start control and changes from the boost start injection amount that is being gradually changed to the normal start injection amount, the air-fuel ratio will fluctuate because the engine 10 has already started, which could cause a shock to the vehicle 1.

[0035] In the example in Figure 4, the case where an interruption request due to abnormal diagnosis occurs while the accelerator is off is explained. However, if an interruption request due to a start request occurs while the boost start control is in operation and before the gradual change begins, the system switches to normal start control, and after the engine 10 starts, the injection amount is gradually changed from the normal start injection amount to the requested injection amount according to the accelerator opening. Also, if an interruption request due to a start request occurs while the boost start control is in operation and after the gradual change has begun, the injection amount is gradually changed from the boost start injection amount to the normal start injection amount to the requested injection amount according to the accelerator opening.

[0036] Figure 5 is an example of a map that defines the initial values ​​for the boost fuel increase and the normal fuel increase, depending on the coolant temperature of the engine 10. Both initial values ​​are set to larger values ​​as the coolant temperature of the engine 10 decreases. The ECU 50 sets these initial values ​​by referring to the map in Figure 5. This is because as the coolant temperature of the engine 10 decreases, fuel adheres to the inner wall surface of the bore 31, increasing the amount of unburned fuel. These initial values ​​may change in a curve-like manner or in steps depending on the coolant temperature. Alternatively, these initial values ​​may be calculated using a formula that takes the coolant temperature as an argument. Furthermore, these initial values ​​may be set according to the throttle opening. For example, the larger the throttle opening, the larger the initial value may be set. The rate of decrease in the fuel increase due to gradual change may also be set according to the coolant temperature.

[0037] Furthermore, as mentioned above, the amount of fuel injection is gradually changed even in normal starting control, so in this case as well, the occurrence of shocks in vehicle 1 is suppressed.

[0038] Although embodiments of the present invention have been described in detail above, the present invention is not limited to these specific embodiments, and various modifications and changes are possible within the scope of the gist of the present invention as described in the claims. [Explanation of Symbols]

[0039] 1 vehicle 10 Engines 41D In-cylinder injection valve (fuel injection valve) 41P Port Injection Valve (Fuel Injection Valve) 50 ECU (Control Unit, Normal Start Control Unit, Updraft Start Control Unit)

Claims

1. A control device for a vehicle equipped with an engine having a fuel injection valve, A normal start control unit that performs normal start control to start the engine by controlling the amount of fuel injected from the fuel injector to the normal start injection amount, The engine is started by controlling the fuel injection amount to a boost-start injection amount greater than the normal starting injection amount so that the engine speed increases during startup compared to the normal starting control, and after the engine has started, the fuel injection amount is gradually changed from the boost-start injection amount to a required injection amount corresponding to the required driving force to the engine. The normal starting control unit, in the normal starting control, gradually changes the fuel injection amount from the normal starting injection amount to the requested injection amount after the engine has started. If the upward starting control is being executed and there is a request to interrupt the upward starting control before the gradual change from the upward starting injection amount to the requested injection amount begins, the normal starting control unit and the upward starting control unit switch from the upward starting control to the normal starting control and switch the fuel injection amount from the upward starting injection amount to the normal starting injection amount. A vehicle control device wherein, while the upward starting control is being executed and a request to interrupt the upward starting control is made during the gradual change from the upward starting injection amount to the requested injection amount, the upward starting control unit continues the gradual change from the upward starting injection amount to the requested injection amount.

2. The vehicle control device according to claim 1, wherein the interruption request refers to the case where there is a request to start the vehicle.

3. The control device for the vehicle according to claim 1, wherein the interruption request occurs when it is diagnosed that there is an abnormality in the engine.

4. The vehicle control device according to any one of claims 1 to 3, wherein the upward starting control unit increases the upward starting injection amount as the temperature of the engine's coolant decreases.

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