Simulation method of water exposure in cabin

Abstract

To provide a water exposure simulation method that enables appropriate water exposure simulation around a connector of an in-cabin component.SOLUTION: A water exposure simulation method for an internal unit mounted in a vehicle, which is executed by a computer, includes: a first step of setting water droplets to be attached to a surface of a predetermined in-cabin component included in the internal unit; a second step of setting deceleration to be applied to the vehicle; a third step of setting a forward tilt angle at which the vehicle is tilted forward; and a fourth step of performing water exposure simulation at the time of sudden braking by inputting the deceleration and the forward tilt angle for predetermined time while performing water exposure simulation during traveling of the vehicle in a state where the water droplets are attached to the in-cabin component.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a method for simulating a water damage condition in a vehicle cabin during sudden braking of the vehicle. [Background technology]

[0002] Patent Document 1 discloses a method for efficiently and quantitatively evaluating the inclusion bounce characteristics of a tire when the tire passes over an inclusion such as a water film on the road surface. This evaluation method involves creating a tire model, a road surface model, and an inclusion model, rolling the tire model on the road surface model on which the inclusion model is provided to scatter micromodels, projecting the scattered micromodels onto a plane perpendicular to the surface of the road surface model, and evaluating the inclusion bounce characteristics of the tire using the projected image of the micromodel projected onto the plane. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-252748 Summary of the Invention [Problem to be solved by the invention]

[0004] Connectors connected to interior components such as electronic control units (ECUs) located inside the vehicle are generally non-waterproof. If water gets on these non-waterproof connectors, the terminals may corrode, resulting in poor electrical continuity. Therefore, it is advisable to conduct a water break simulation around the connectors of interior components and design the position and orientation of the interior components and connectors.

[0005] When the method described in Patent Document 1 is used to simulate water rupture around a connector in a vehicle interior part, it is possible to perform an evaluation while the vehicle is moving or stopped, but there is a problem in that it is not possible to evaluate situations where there is a sudden change in kinetic energy, such as when the brakes are applied suddenly, and therefore it is not possible to perform an appropriate simulation.

[0006] The present disclosure has been made in consideration of the above-mentioned problems, and aims to provide a water damage simulation method that can appropriately perform a water break simulation around a connector of a vehicle interior part. [Means for solving the problem]

[0007] In order to solve the above-mentioned problems, one aspect of the disclosed technology is a water damage simulation method for an internal unit mounted on a vehicle, executed by a computer, which includes: a first step of setting water droplets to adhere to the surface of a specified interior vehicle component included in the internal unit; a second step of setting a deceleration to be applied to the vehicle; a third step of setting a forward tilt angle to tilt the vehicle forward; and a fourth step of performing a water damage simulation during sudden braking by inputting the deceleration and forward tilt angle for a specified period of time while performing a water damage simulation while the vehicle is traveling with water droplets attached to the interior vehicle component. [Effects of the Invention]

[0008] According to the water damage simulation method of the present disclosure, it is possible to appropriately simulate water breakage around a connector of an interior vehicle component not only while the vehicle is moving or stopped, but also during sudden braking. [Brief explanation of the drawings]

[0009] [Figure 1] A flowchart showing a processing procedure of a vehicle interior water damage simulation method according to an embodiment of the present disclosure. [Figure 2] A diagram showing an example of the relationship between saturated water vapor amount, temperature, and humidity. [Figure 3]FIG. 10 is a diagram illustrating an example of particle contact angles set in a particle model. [Figure 4] A diagram illustrating an example of kinetic friction force set in a particle model. [Figure 5] A diagram explaining an example of water droplet settings [Figure 6] An example of parameters to input into water damage simulation software [Figure 7] Illustration showing water droplets falling from an air conditioning duct onto a connector DETAILED DESCRIPTION OF THE INVENTION

[0010] <Embodiment> The vehicle interior water damage simulation method of the present disclosure can be used to simulate the movement of water droplets that condense on vehicle interior components included in a vehicle interior unit. Below, the vehicle interior water damage simulation method of the present disclosure will be described using an air conditioning duct (air conditioning duct) as an example of a vehicle interior component on which water droplets condense.

[0011] [control] 1 is a flowchart illustrating a processing procedure of a vehicle interior water damage simulation method according to an embodiment of the present disclosure. The water damage simulation method shown in FIG. 1 is executed by a computer (such as an ECU) installed in a vehicle.

[0012] (Step S110) The computer calculates the amount of condensation that will form on the air conditioning duct. Specifically, the computer first calculates the maximum amount of condensation that will form on the surface of the air conditioning duct based on the amount of saturated water vapor.

[0013] Maximum condensation amount [g / m 3 ] is calculated using the following formulas (1) and (2): In formula (1), a(t) is the saturated water vapor amount [g / m 3 ], e(t) is the saturated water vapor pressure, and t is the temperature [°C].

[0014]

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[0015]

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[0016] Figure 2 shows an example of the relationship between the amount of saturated water vapor and temperature and humidity. In Figure 2, in state B, where the temperature is 20°C and the humidity is 100%, the actual amount of water vapor is equal to the amount of saturated water vapor, and there is no water vapor that forms droplets. In state C, where the temperature is 30°C and the humidity is 57%, the actual amount of water vapor is smaller than the amount of saturated water vapor, at 13.0 (= 30.3 - 17.3) g / m 3 On the other hand, in condition A, where the temperature is 10°C and the humidity is 100%, the actual amount of water vapor exceeds the saturated amount, and the excess amount is 7.9 (= 17.3 - 9.4) g / m 3 This is the state in which water vapor condenses into water droplets.

[0017] Once the maximum amount of condensation is calculated, the computer then generates a particle model that satisfies the maximum amount of condensation.

[0018] In generating this particle model, the computer determines the particle contact angle and kinetic friction force as influential factors necessary for analysis, from among the various influential factors in addition to particle size, such as surface roughness, flow rate / flow velocity, particle contact angle (contact angle), liquid temperature, part temperature, dirt on the part, liquid density, fall position, assembly tolerance, and kinetic friction force (viscosity and friction force), and sets the values ​​of the particle contact angle and kinetic friction force to be applied to the particle model.

[0019] Particle size is the diameter of the particle. The particle contact angle quantifies the wettability between a particle and a solid. For example, as shown in Figure 3, if the contact angle between particle 310 and the surface of vehicle interior part 330 is small (θ1), the particle is hydrophilic, and if the contact angle between particle 320 and the surface of vehicle interior part 330 is large (θ2), the particle is water-repellent. The kinetic friction force is the force that hinders movement at the contact surface. For example, for particle 410 present on the inclined surface of vehicle interior part 420, the relationship shown in Figure 4 holds.

[0020] The computer then determines particle movement by substituting the particle contact angle φ and kinetic friction force ν, which have been determined (set) as influential factors required for the analysis, into the following equation (3). Note that ∇φ in equation (3) is given by the following equation (4).

[0021]

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[0022]

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[0023] Once the particle model is generated, the computer then performs particle placement in the air conditioning duct.

[0024] When arranging the particles, the computer calculates the flow rate of water flowing on the surface of the air conditioning duct based on the generated particle model and a predetermined thinning rate. The computer calculates the flow rate of water flowing on the surface of the air conditioning duct based on the inflow position, inflow direction, flow velocity [cm / sec], inflow size [cm 2 ] and thinning rate [%] are determined to arrange the particles 510 in a manner equivalent to that of an air conditioning duct 520 of an actual vehicle, as shown in Fig. 5. Then, the flow rate [cm 3 / sec]. The flow rate can be calculated using the following formula (5).

[0025]

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[0026] The number of condensed water droplets in the air conditioning duct is calculated by the above calculation. Once the number of condensed water droplets has been calculated by the computer, the process proceeds to step S120.

[0027] (Step S120) The computer sets the analysis conditions used in the water damage simulation, including the water droplets, deceleration, and forward tilt angle.

[0028] The water droplets are set to the water droplets calculated in step S110. The deceleration α is the rate of change of the speed per unit time [m / s 2 ], which is a negative acceleration. The forward tilt angle is the angle at which the posture of the vehicle body changes when the vehicle traveling at the above-mentioned speed V stops at the deceleration α, and specifically, it is the maximum angle at which the front of the vehicle drops (as the suspension sinks) due to sudden braking.

[0029] The deceleration and forward tilt angle are set based on the sudden braking state of the vehicle to be simulated. These set values ​​are typically obtained by performing a sudden braking experiment using an actual vehicle, in which the vehicle is braked from a running state at speed V to a stopped state at zero speed, and actually measuring the time from when the vehicle brakes until it stops and the maximum angle at which the vehicle tilts forward during braking.

[0030] Once the analysis conditions for the water damage simulation are set by the computer, the process proceeds to step S130.

[0031] (Step S130) The computer performs a water damage simulation of the vehicle interior parts based on the analysis conditions (water droplets, deceleration, and forward tilt angle) set in step S120. This water damage simulation is performed in the following procedure.

[0032] First, the parameters for water droplets under the analysis conditions are input into the water damage simulation software to reproduce the condition of condensation occurring in the air conditioning duct in the simulation (top of Figure 6).

[0033] Next, after a predetermined time has elapsed, the deceleration and forward tilt angle under the analysis conditions are input as parameters into the water damage simulation software to simulate the state of a vehicle suddenly braking (middle and bottom panels of Figure 6). By inputting these deceleration and forward tilt angle as parameters for a predetermined period of time, it is possible to simulate the situation in which the vehicle tilts forward due to the sudden change in kinetic energy caused by sudden braking, and the law of inertia acts to push the liquid forward, causing water droplets to fall forward from the air conditioning duct. As a result, for example, in the case where a non-waterproof connector 720 is located in the path of water droplets falling from an air conditioning duct 710, as illustrated in Figure 7, it is possible to perform a water damage test on the connector 720 using only the simulation, without using an actual vehicle.

[0034] This completes the computer-generated water damage simulation for the vehicle interior parts. After the water damage simulation is complete, the results of the water damage status of each vehicle interior part, including the air conditioning duct, are confirmed, and the process ends.

[0035] <Actions and Effects> As described above, in the vehicle interior water damage simulation method according to one embodiment of the present disclosure, water droplets adhering to the surfaces of vehicle interior components such as air conditioning ducts are set, the deceleration to be applied to the vehicle is set, and the forward tilt angle at which the vehicle is tilted forward is set. Then, while performing a water damage simulation while the vehicle is traveling with water droplets adhering to the vehicle interior components, the deceleration and forward tilt angle are input for a predetermined period (time) to perform a water damage simulation during sudden braking.

[0036] This process allows for appropriate simulation of water breakage around connectors in vehicle interior components for a wider range of driving scenarios, including sudden braking, as well as when the vehicle is moving or stopped.

[0037] In order to improve the accuracy of the water-break simulation using the parameters of deceleration and forward tilt angle, it is desirable to verify the results of the water-break simulation based on the behavior (distance) of water droplets scattering from interior components obtained from sudden braking experiments using an actual vehicle. [Industrial Applicability]

[0038] The present disclosure can be used, for example, when simulating the condition of interior vehicle components being wetted when the vehicle brakes suddenly. [Explanation of symbols]

[0039] 310, 320, 410, 510 particles (water droplets) 330, 420 Vehicle interior parts 520, 710 Air conditioning duct 720 Connector

Claims

1. A computer-implemented method for simulating water damage to an internal unit mounted on a vehicle, comprising: a first step of setting water droplets adhering to a surface of a predetermined interior component included in the internal unit; a second step of setting a deceleration to be applied to the vehicle; a third step of setting a forward tilt angle for tilting the vehicle forward; a fourth step of performing a water damage simulation during sudden braking by inputting the deceleration and the front tilt angle for a predetermined period of time while performing a water damage simulation during driving of the vehicle with the water droplets attached to the interior parts of the vehicle; Water damage simulation method.

2. The vehicle interior component to which the water droplets adhere is a duct of an air conditioning system of the vehicle. The water damage simulation method according to claim 1 .

3. The deceleration and the forward tilt angle are obtained by reproducing the actual vehicle traveling from a predetermined speed to a stopped state. The water damage simulation method according to claim 1 or 2.

4. The first step comprises: calculating an amount of condensation adhering to a surface of the vehicle interior component based on the amount of saturated water vapor; Generate a particle model that satisfies the amount of condensation; calculating the water droplets on the surface of the vehicle interior part based on the particle model and a predetermined thinning rate; The water damage simulation method according to any one of claims 1 to 3.

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