SU1440783A1 - Car body with front fenders - Google Patents

Abstract

This invention relates to the automotive industry and is intended to reduce air resistance when a vehicle is moving. The purpose of the invention is to increase fuel efficiency by eliminating flow separation from the side surfaces of the body. For this hole 6, located at the height of the wings, are connected to the suction filter 3 of the engine 2. 2 Il.

Description

(L

00 WITH

e.2

The invention relates to the automotive industry, namely to passenger cars.

The aim of the invention is to increase fuel efficiency by eliminating flow separation from the side surfaces of the body.

FIG. 1 shows the described body, general view; in fig. 2 - the same, top view.

In the body I of a passenger car, in front of the engine 2 is located with a suction filter 3. On the side surfaces of the front wings between the wheelchair beggar 4 and the door 5 there are holes 6 with a diameter of 0.01-0.02 wing height and schagom 1.5-2 diameter. These holes are connected by special channels 7 to the suction filter 3. In order to prevent flow separation, it is necessary that the air flow rate of the suction device be comparable with the flow rate in the boundary layer. This expense is equal to

G ,, ()

where p is the density of air in the boundary layer;

L is the width of the boundary layer, equal to the length of the line along which suction is performed.

The displacement thickness for a flat plate with a turbulent flow is equal to

0,019Х.

(2)

where X is the distance from the beginning of the plate (wing) to the suction point of the boundary layer. Reynolds number

vX

their

 V 15-10 (3)

where V is the coefficient of roughness,

V is the flow velocity (car). Engine fuel consumption (kg / h) is equal to

.0 G (Va

 - JO &,

(four)

Q - travel fuel consumption, liters per 100 km;

p is the density of gasoline, 750

On - car speed, km / h.

Engine air consumption (kg / s) at 1 and 7 kg / kg

G..4.08 10-Gr

(5) 50

45

55

where Gin - hourly fuel consumption;

a - coefficient of excess air; LO is the air density. Air velocity in the holes on the wing

 Smiling

(6)

where g and d are the number and diameter of the holes, respectively.

Determine the pitch, location and number of holes required for suction of the boundary layer. Experiments on the plates show that successful suction is carried out if the holes occupy 0.7-0.9 the width of the plate. We take this value equal to 0.8. In this case, the suction helps to keep the boundary layer from detachment. For design reasons, the hole diameter should be at least 5 and no more than 10 mm. Experiments show that it is most convenient to arrange the holes in 2-3 rows in a shakhmatny order.

From elementary geometric considerations, the number of suction holes on the wing should be equal to

, 8 / d

(7)

 where / is the height of the wing;

k is the fraction of the height of the wing, occupied by holes, which is assumed to be equal to 0.8.

25

The pitch of the holes, i.e. the distance between the centers of adjacent holes is equal to

s, 2bid, 1

(eight)

where i is the number of rows of holes taken

equal to 2-3.

For a VAZ car at a speed of 72 km / h (20 m / s) at a distance of 6 m from the start of the wing, the Reynolds number is 6.995-10 (formula 3), the displacement thickness is 1.696 mm (2). The flow through the boundary layer with an air density of 1.22 kg / m and a wing height of 0.75 m is equal to 0.00155 kg / s (1), through two wings Gnc is equal to 0.0031 kg / s. The fuel consumption Q at a speed of 72 km / h is 6 l / 100 km. Engine fuel consumption is 3.24 kg / h (4). Air consumption is 0,0132 kg / s (5).

Thus, the engine air flow is much larger than the flow through the boundary layer and suction will be carried out successfully.

Accepting the diameter of the holes, 01 m, the number of rows 2, we define their number () and pitch (mm).

The device works as follows.

When moving on the lateral surface of the wings of an automobile, a boundary layer is formed, which tends to be detached. Through the openings 6, the air from the boundary layer is sucked off by the engine through the channels 7 and filter 3. This reduces the danger of boundary layer separation and reduces the drag coefficient and air resistance.

Claims (1)

Invention Formula The body of a passenger car with front wings, fitted with a wheel housing and doors, mainly with a carburetor engine, has a water filter, characterized in that it is equipped with air ducts to increase fuel efficiency by eliminating the flow from the side surfaces of the body. this on the side surface of each front wing between the wheel housing and the door is made at the height of the wing in not how many rows are in the staggered order of the holes communicated by the said air ducts with the engine air filter, while the number of holes and the distance between them are made in accordance with the expressions: , 8 and, 25id, where Z is the number of holes; / - wing height; d is the diameter of the hole; t is the number of rows of holes; S is the distance between the holes. as.f