Fuel property estimation device

Abstract

To provide a fuel property estimation device capable of estimating fuel properties corresponding to an alcohol concentration while suppressing the number of vehicle components.SOLUTION: A fuel property estimation device is applied to an engine mounted to a vehicle. The fuel property estimation device includes: an acquisition section that acquires request torque to the engine and acceleration of the vehicle; and an estimation section that estimates properties of fuel that is used in the engine corresponding to an alcohol concentration in the fuel on the basis of the request torque and the acceleration.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a fuel property estimation device.

Background Art

[0002] When fuels with different properties in terms of alcohol concentration are used in an engine mounted on a vehicle, there is a technique for controlling the fuel injection amount of the engine according to the alcohol concentration in the fuel (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 the above technique, an alcohol concentration sensor is used to estimate the properties of the fuel. For this reason, the number of vehicle parts is increasing.

[0005] Therefore, an object of the present invention is to provide a fuel property estimation device that can estimate the properties of fuel according to the alcohol concentration while suppressing the number of vehicle parts.

Means for Solving the Problems

[0006] The above object can be achieved by a fuel property estimation device applied to an engine mounted on a vehicle, the fuel property estimation device including: an acquisition unit that acquires a required torque for the engine and an acceleration of the vehicle; and an estimation unit that estimates the properties of the fuel according to the alcohol concentration in the fuel used in the engine based on the required torque and the acceleration.

Effects of the Invention

[0007] According to the present invention, it is possible to provide a fuel property estimation device that can estimate the properties of fuel according to the alcohol concentration while suppressing the number of parts of the vehicle.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Embodiments for Carrying Out the Invention

[0009] [Schematic Configuration of Vehicle] FIG. 1A is a schematic configuration diagram of the vehicle 1 of this embodiment. In FIG. 1A, the vehicle 1 includes an engine 10, a torque converter 20, an automatic transmission 22, a propeller shaft 26, an axle 30, drive wheels 32, and an ECU (Electronic Control Unit) 50. The engine 10 is a gasoline engine that is a driving force source for traveling. A fuel tank 12 storing the fuel used in the engine 10 is connected to the engine 10. The torque converter 20 is a fluid transmission device connected to the engine 10. The automatic transmission 22 is connected to the torque converter 20. Power from the engine 10 is transmitted to the automatic transmission 22 via the torque converter 20. The propeller shaft 26 is connected to the output shaft 24 of the automatic transmission 22. A differential gear device 28 is connected to the propeller shaft 26. The drive wheels 32 are connected to the differential gear device 28 via the axle 30.

[0010] 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 1, and a memory in which control programs and data are stored.

[0011] A sensor group 60 composed of a plurality of sensors is electrically connected to the ECU 50. The sensor group 60 includes an acceleration sensor, a vehicle speed sensor, and an accelerator opening sensor. The acceleration sensor detects the acceleration of the vehicle 1. The vehicle speed sensor detects the speed of the vehicle 1. The accelerator opening sensor detects the accelerator opening, which is the amount of operation on the accelerator pedal operated by the driver.

[0012] The ECU 50 calculates the required torque for the engine 10 based on the operating state of the engine 10 and the accelerator opening. The ECU 50 adjusts the ignition timing, fuel injection amount, fuel pressure, etc. of the engine 10 so that the output torque of the engine 10 becomes the required torque. The ECU 50 is an example of a fuel property estimation device, and specifically, it functionally realizes an acquisition unit and an estimation unit, which will be described later in detail.

[0013] [Fuel Property Estimation Control] Figure 1B is a flowchart illustrating the fuel property estimation control. Figure 2A is a timing chart illustrating the fuel property estimation control. Figure 2A shows the transitions of the vehicle speed, the required torque for the engine 10, and the acceleration of the vehicle 1. First, the ECU 50 determines whether the preconditions for estimating the fuel properties are satisfied (step S1). The precondition is that the required torque for the engine 10 is increasing from the stopped state. If the answer in step S1 is No, this control ends.

[0014] If the answer in step S1 is Yes, the ECU 50 acquires the required torque of the engine 10 and the acceleration of the vehicle 1 (step S2). Specifically, the ECU 50 acquires the maximum value of the required torque in the state where the preconditions are satisfied, and the acceleration when the required torque reaches the maximum value. The reason for acquiring the maximum value is that the greater the required torque, the greater the difference in acceleration according to the fuel properties, and the estimation accuracy of the fuel properties is improved. Note that the ECU 50 acquires the acceleration of the vehicle 1 based on the acceleration sensor described above, but it is not limited thereto. For example, the acceleration may be calculated based on the detection value of a sensor that detects the rotational speed of the wheels of the vehicle 1. Step S2 is an example of the process executed by the acquisition unit.

[0015] In the example of FIG. 2A, the required torque starts to increase from the stopped state, and the vehicle speed and the acceleration of vehicle 1 also start to increase (time t1). Thereafter, the required torque starts to decrease (time t2). The above-mentioned prerequisite conditions are satisfied between time t1 and time t2. The ECU 50 acquires the maximum value Q of the required torque during this period and the acceleration A at the time when the required torque reaches the maximum value Q.

[0016] Next, based on the acquired required torque and acceleration, the ECU 50 estimates the properties according to the alcohol concentration of the fuel used in the engine 10 with reference to the discrimination map of FIG. 2B (step S3). In this embodiment, it is estimated whether the fuel used is E0 fuel or E20 fuel. E0 fuel is gasoline fuel that does not contain ethanol. E20 fuel is gasoline fuel that contains 20% ethanol by volume ratio. Step S3 is an example of the process executed by the estimation unit.

[0017] FIG. 2B is an exemplary view of a discrimination map defining the relationship between the required torque and the acceleration. The horizontal axis represents the required torque, and the vertical axis represents the acceleration. In the case where either E0 fuel or E20 fuel is used, the acceleration increases as the required torque increases. However, when the required torque is the same, the acceleration of E20 fuel is higher than that of E0 fuel. This is because E20 fuel has higher knock resistance than E0 fuel, the ignition timing is controlled on the advanced side, the latent heat of vaporization is large, and the intake efficiency is high.

[0018] The discrimination line for discriminating between E0 fuel and E20 fuel shown in FIG. 2B indicates a higher value of acceleration as the required torque is higher. Therefore, when the acceleration is greater than the discrimination line, it is estimated as E20 fuel, and when the acceleration is less than the discrimination line, it is estimated as E0 fuel. This discrimination map is stored in the ROM in advance. Since the fuel properties are estimated as described above, an alcohol concentration sensor is not required, and the number of components of vehicle 1 is suppressed.

[0019] When driving on an uphill road, the acceleration with respect to the required torque decreases compared to when driving on a flat road. However, when driving on an uphill road, the acceleration when using E0 fuel is lower than the discrimination line, and the acceleration when using E20 fuel is greater than the discrimination line. Therefore, the ECU 50 can estimate the properties of the fuel being used whether driving on a flat road or an uphill road.

[0020] The properties of the fuel estimated as described above are used, for example, to switch the base map. For example, when the fuel being used is estimated to be E0 fuel, the ECU 50 uses the E0 base map. The E0 base map is a map for controlling the ignition timing, fuel injection amount, fuel pressure, etc. on the premise of using E0 fuel. When the fuel being used is estimated to be E20 fuel, the ECU 50 uses the E20 base map. The E20 base map is a map for controlling the ignition timing, fuel injection amount, fuel pressure, etc. on the premise of using E20 fuel. By switching the base map according to the fuel being used in this way, the engine 10 can be appropriately controlled according to the fuel being used.

[0021] In the above embodiment, the case where it is determined whether the fuel being used is E0 fuel or E20 fuel has been described as an example, but it is not limited to this. For example, it may be determined whether the fuel being used is E0 fuel, E10 fuel, or E20 fuel. In this case, for example, a first discrimination line and a second discrimination line with an acceleration greater than the first discrimination line may be provided on the discrimination map. When the acceleration is less than the first discrimination line, it may be estimated as E0 fuel, when the acceleration is between the first discrimination line and the second discrimination line, it may be estimated as E10 fuel, and when the acceleration is greater than the second discrimination line, it may be estimated as E20 fuel.

[0022] As described above in detail with respect to the embodiments of the present invention, the present invention is not limited to such specific embodiments, and various modifications and changes are possible within the scope of the gist of the present invention described in the claims.

Explanation of Reference Numerals

[0023] 1 Vehicle 10 Engine 50 ECU (Fuel property estimation device, acquisition unit, estimation unit)

Claims

[Claim 1] A fuel property estimation device applied to an engine mounted on a vehicle, an acquisition unit that acquires a required torque for the engine and an acceleration of the vehicle; an estimation unit that estimates a property of the fuel used in the engine according to an alcohol concentration of the fuel based on the required torque and the acceleration.

Images