Vehicle control system
The vehicle control device addresses exhaust emission deterioration by employing conditional start-up controls and ignition timing adjustments to balance sportiness and emissions.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- TOYOTA JIDOSHA KK
- Filing Date
- 2024-11-21
- Publication Date
- 2026-06-02
AI Technical Summary
Increasing the surge speed at engine startup to enhance vehicle sportiness can lead to deteriorated exhaust emissions.
A vehicle control device with port and in-cylinder injection valves, utilizing a cold-start, high-altitude, and warm-up prediction determination to execute normal or rev-up start-up controls, adjusting ignition timing and fuel injection based on engine and environmental conditions.
Enhances vehicle sportiness while suppressing exhaust emission deterioration.
Smart Images
Figure 2026090059000001_ABST
Abstract
Description
Technical Field
[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
[0004] In some cases, the sportiness of a vehicle may be enhanced by increasing the surge speed at engine startup. However, increasing the surge speed at engine startup may, in some cases, deteriorate exhaust emissions.
[0005] Therefore, an object of the present invention is to provide a control device for a vehicle that can enhance sportiness while suppressing deterioration of exhaust emissions.
Means for Solving the Problems
[0006] The above objective can be achieved by a vehicle control device for an engine equipped with port injection valves and in-cylinder injection valves, comprising: a cold-start determination unit for determining whether the engine is in a cold state; and a start-up control unit for starting the engine, wherein the start-up control unit performs normal start-up control by injecting fuel from at least one of the port injection valves and in-cylinder injection valves to start the engine if the cold-start determination unit makes a positive determination; and performs rev-up start-up control by injecting fuel only from the in-cylinder injection valve to increase the rev-up speed of the engine at startup compared to the normal start-up control if the cold-start determination unit makes a negative determination.
[0007] The vehicle is equipped with a high-altitude determination unit that determines whether or not the vehicle is at high altitude. The starting control unit may execute the normal starting control if at least one of the cold-start determination unit and the high-altitude determination unit makes a positive determination, and execute the blow-up starting control if both the cold-start determination unit and the high-altitude determination unit make a negative determination.
[0008] The system includes a warm-up prediction determination unit that predicts whether or not a warm-up of the catalyst for purifying the exhaust gas of the engine is required during engine startup, and if at least one of the cold start determination unit, the high altitude determination unit, and the warm-up prediction determination unit makes a positive determination, the start control unit executes the normal start control, and if all of the cold start determination unit, the high altitude determination unit, and the warm-up prediction determination unit make a positive determination, the start control unit executes the blow-up start control.
[0009] In the rev-up starting control, the starting control unit may adjust the ignition timing of the engine differently in each of the low-speed range, the medium-speed range, and the high-speed range, in which the engine speed progresses in the order of low-speed range, medium-speed range, and high-speed range, where the engine speed is higher than the medium-speed range and the rate of increase in engine speed is high.
[0010] The starting control unit may set the ignition timing of the engine in the low-speed range to be more advanced than the ignition timing in the medium-speed range and the high-speed range, respectively. [Effects of the Invention]
[0011] According to the present invention, it is possible to provide a vehicle control device that can enhance sportiness while suppressing deterioration of exhaust emissions. [Brief explanation of the drawing]
[0012] [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 blow-up start control. [Modes for carrying out the invention]
[0013] [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. A transmission and differential gear (not shown) are provided in the power transmission path from the engine 10 to the drive wheels 13.
[0014] 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.
[0015] 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.
[0016] 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. The crankshaft 35 is forcibly rotated by the starter 16 when the engine 10 is started.
[0017] 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.
[0018] 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. Note that only one of the in-cylinder injection valve 41D and the port injection valve 41P may be provided.
[0019] An exhaust passage 37 is provided with a three-way catalyst 43 and a GPF (Gasoline Particulate Filter) 44. The three-way catalyst 43 contains a catalyst metal, has an oxygen storage capacity, and purifies NOx, HC, and CO. The GPF 44 is a porous ceramic structure that collects exhaust particles (hereinafter referred to as PM (Particulate Matter)) in the exhaust gas. The GPF 44 is an example of a filter. When the engine 10 is a diesel engine, for example, a DPF (Diesel Particulate Filter) is provided instead of the GPF 44.
[0020] 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 for the vehicle 1, and specifically, functionally realizes a cold determination unit, a start control unit, a highland determination unit, and a warm-up prediction determination unit, which will be described later.
[0021] An ignition switch 61, a crank angle sensor 62, an air flow meter 63, a water temperature sensor 66, and an atmospheric pressure sensor 67 are connected to the ECU 50. The ignition switch 61 detects the on / off of the ignition. 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.
[0022] Based on the detection signals of the above-described sensors, the ECU 50 controls the driving of the engine 10 by controlling the opening degree 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, and the like.
[0023] [Engine Start Control] Figure 2 is a flowchart illustrating engine start control. This control is executed repeatedly while the ignition is on. The ECU 50 determines whether or not there is a request to start the engine 10 (step S1). A request to start the engine 10 is made, for example, when the ignition is switched from off to on, or when the restart conditions after automatic stopping are met. If the answer in step S1 is No, this control is terminated.
[0024] If the answer in step S1 is Yes, the ECU 50 determines whether the engine 10 is in a cold state (step S2). Specifically, if the temperature of the coolant in the engine 10 is below a predetermined temperature, it is determined that the engine 10 is in a cold state. Step S2 is an example of the process performed by the cold state determination unit.
[0025] If the answer in step S2 is No, the ECU 50 determines whether or not vehicle 1 is at high altitude (step S3). Specifically, if the value detected by the atmospheric pressure sensor is lower than or equal to a predetermined value than the standard atmospheric pressure, it is determined that vehicle 1 is at high altitude. Step S3 is an example of the process performed by the high altitude determination unit.
[0026] If the answer in step S3 is No, the system predicts whether or not the three-way catalytic converter 43, which purifies the exhaust gas of the engine 10, needs to be warmed up while the engine 10 is running (step S4). Here, the warm-up of the three-way catalytic converter 43 is required if the temperature of the three-way catalytic converter 43 during the engine 10 is below a predetermined temperature. The temperature of the three-way catalytic converter 43 is estimated by considering, for example, the temperature of the exhaust gas at the time of engine 10 startup, estimated based on the temperature of the coolant when the engine 10 was stopped last time and the temperature of the coolant when it is started this time, the heat transfer coefficient of the exhaust passage 37, and the amount of heat generated by the unburned fuel in the three-way catalytic converter 43. The temperature of the three-way catalytic converter 43 may be estimated by methods other than those described above, detected by a sensor, or calculated by other known methods. Step S4 is an example of the process performed by the warm-up prediction determination unit.
[0027] If the answer to "Yes" in at least one of steps S2 to S4, the ECU 50 performs normal start control (step S5). In normal start control, the starter 16 starts cranking the engine 10, fuel is injected from at least one of the in-cylinder injector 41D and the port injector 41P, and the opening of the throttle valve 40 is controlled to the closed position. Specifically, the in-cylinder injection rate, which is the ratio of the in-cylinder injection amount to the total fuel injection amount, and the port injection rate, 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.
[0028] If the answer is No in all steps S2 to S4, the ECU 50 performs a boost start control (step S6). In boost start control, the starter 16 starts cranking the engine 10, 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 boost start control, the boost RPM at which the engine 10 starts 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 the deterioration of exhaust emissions. Note that injection from the in-cylinder injector 41D occurs once per combustion cycle. Also, the amount of fuel injected in boost start control is greater than the amount of fuel injected in normal start control.
[0029] As described above, when the engine 10 is cold, normal starting is performed and upward starting control is not performed. This is because if upward starting control is performed when the engine 10 is cold, the amount of fuel injected in upward starting control is greater than in normal starting control, which increases the amount of fuel adhering to the bore 31 and may worsen exhaust emissions.
[0030] Furthermore, if vehicle 1 is at high altitude, normal starting is performed and upward starting control is not executed. When vehicle 1 is at high altitude where atmospheric pressure is low, the amount of oxygen introduced into engine 10 decreases compared to when vehicle 1 is at low altitude where atmospheric pressure is high. Therefore, if upward starting control is executed when vehicle 1 is at high altitude, the combustion state of engine 10 may deteriorate, and the starting performance of engine 10 may also deteriorate.
[0031] Furthermore, if it is anticipated that the three-way catalytic converter 43 will need to be warmed up during engine 10 startup, normal starting will be performed and the upward starting control will not be executed. If the three-way catalytic converter 43 needs to be warmed up while upward starting control is being performed, the throttle valve 40 will be controlled from the open side to the closed side, and multiple fuel injections will be performed from at least one of the in-cylinder injection valve 41D and the port injection valve 41P during one combustion cycle. This is because the combustion state will change rapidly, which may worsen exhaust emissions.
[0032] Figure 3 is a timing chart illustrating upward starting control. Figure 3 shows the change in engine speed 10 when upward starting control is performed. The stator 16 starts cranking the engine 10 (time t1), and the engine speed 10 is maintained at a low speed. Subsequently, the engine speed 10 begins to increase (time t2). After that, the rate of increase in engine speed 10 gradually begins to decrease (time t3). The engine speed 10 begins to decrease (time t4). The engine speed 10 is maintained at idle speed (time t5).
[0033] From time t1 to time t2, the engine speed of 10 is low. From time t2 to time t3, the engine speed of 10 is higher than in the low-speed range, and the rate of increase in engine speed is also higher, corresponding to the medium-speed range. From time t3 to time t4, the engine speed of 10 is higher than in the medium-speed range, and the rate of increase in engine speed is lower, corresponding to the high-speed range. In each of these low-speed, medium-speed, and high-speed ranges, the ignition timing of engine 10 is set to a different time. This is because engine 10 is controlled so that its speed and the rate of increase in engine speed differ in these regions.
[0034] Specifically, the ECU50 sets the ignition timing at low RPMs to be advanced beyond MBT (Minimum advance for the Best Torque) and more advanced than the ignition timing at mid-range and high-range RPMs. This is because the combustion speed of the air-fuel mixture is slower at low RPMs, and this is necessary to ensure ignition of the mixture. Furthermore, at mid-range and high RPMs, the ignition timing is gradually retarded, eventually being set to around MBT (Minimum advance for the Best Torque). This is because it is necessary to increase the engine speed at mid-range RPMs and to maintain the engine speed at high RPMs.
[0035] 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]
[0036] 1 vehicle 10 Engines 41D In-cylinder injection valve 41P Port Injection Valve 50 ECU (Control unit, cold start detection unit, start control unit, high altitude detection unit, warm-up prediction detection unit)
Claims
1. A control device for a vehicle equipped with an engine having port injection valves and in-cylinder injection valves, A cold start determination unit that determines whether the engine is in a cold state, The engine comprises a starting control unit for starting the engine, A vehicle control device comprising: a starting control unit which, when a positive determination is made by the cold start determination unit, performs normal starting control to start the engine by injecting fuel from at least one of the port injection valve and the in-cylinder injection valve; and when a negative determination is made by the cold start determination unit, performs rev-up starting control which, when fuel is injected only from the in-cylinder injection valve, increases the rev-up speed at which the engine starts compared to the normal starting control.
2. The vehicle is equipped with a high-altitude determination unit that determines whether or not it is at high altitude. The vehicle control device according to claim 1, wherein the starting control unit executes the normal starting control when an affirmative determination is made by at least one of the cold starting determination unit and the high altitude determination unit, and executes the blow-up starting control when a negative determination is made by both the cold starting determination unit and the high altitude determination unit.
3. Before starting the engine, the system includes a warm-up prediction determination unit that predicts whether or not a warm-up of the catalyst that purifies the engine's exhaust gases is required during the engine's operation. The vehicle control device according to claim 2, wherein if a positive determination is made in at least one of the cold start determination unit, the high altitude determination unit, and the warm-up prediction determination unit, the start control unit executes the normal start control, and if a positive determination is made in all of the cold start determination unit, the high altitude determination unit, and the warm-up prediction determination unit, the start control unit executes the rev-up start control.
4. A vehicle control device according to any one of claims 1 to 3, wherein the starting control unit, in the rev-up starting control, adjusts the ignition timing of the engine differently in the low rotation range, the medium rotation range, and the high rotation range, in the order that the engine rotation speed progresses from a low rotation range, to a medium rotation range where the engine rotation speed is higher than the low rotation range and the rate of increase of the engine rotation speed is high, and to a high rotation range where the engine rotation speed is higher than the medium rotation range and the rate of increase of the engine rotation speed is low.
5. The vehicle control device according to claim 4, wherein the starting control unit sets the ignition timing of the engine in the low rotation range to be more advanced than the ignition timing in the medium rotation range and the high rotation range, respectively.