JPS5888448A - Negative pressure type two-stage carburetter - Google Patents

Abstract

PURPOSE:To prevent knocking of a car by adopting a shape-memorizing alloy for a returning spring of an operation member in a negative pressure operation mechanism to operate a throttle valve of a secondary carburetter on the basis of a Venturi negative pressure for checking the opening of the said throttle valve when an engine is in low temperature. CONSTITUTION:In a secondary carburetter S arranged beside a primary carburetter P, a lever 3 fast fixed on a shaft 2 of its throttle valve 1 is connected with an arm 6 fast fixed on an operation member 5 of a negative pressure operation mechanism 4 to be extended in the direction of operation via a coupling rod 7, and in the negative pressure operation mechanism 4, a resultant negative pressure of Venturi negative pressures of two carburetters P and S is introduced into a negative pressure chamber 8 to suck the operation member 5 via a negative pressure passage 9. In this cas, a spring 10 made of a shape-memorizing alloy is used for a returning spring of the operation member 5 contained in the said negative pressure chamber 8. This spring 10 functions to fix the operation member 5 at the time of low temperature of an engine, on the other hand, gradually contract to return to its original state when the temperature is risen, and gradually increase the movable distance of the operation member.

Description

[Detailed description of the invention]

The present invention particularly relates to a negative pressure operating mechanism of a negative pressure type two-stage carburetor in which the throttle valve of the secondary vaporizer is operated by Be/Turi negative pressure. −Venturi negative pressure of the secondary vaporizer and venturi pressure of the secondary vaporizer
Generally, the die is a composite negative pressure with negative pressure. act on an actuating member consisting of a yaphram, and connect this actuating member with a connecting rod such as a V bar fixed to the throttle valve shaft of the secondary carburetor. In a negative pressure operating mechanism in which the valve is opened, a spring acts on the operating member against the resultant negative pressure, and when the negative pressure overcomes the spring force, the operating member is attracted by the resultant negative pressure. Move to open the throttle valve.In other words, if the combined negative pressure exceeds a certain level, the secondary carburetor will operate immediately after starting in particularly cold conditions.When the engine is sufficiently warmed up, Compared to this, even though a high a degree mixture is required, the mixture supplied to the engine is quite lean due to the addition of the mixture from the secondary carburetor. The present invention prevents the throttle valve of the secondary carburetor from opening when the engine temperature is low, even if the operation is such that the secondary carburetor operates immediately after starting in cold weather. The purpose of this is to eliminate the inconvenience caused by the provision of a shape memory alloy spring that fixes the operating member of the negative pressure operated WIJ horizontal structure at a constant temperature. Shape memory alloys, that is, metal materials with shape memory effect, are
It is known as a material whose shape reversibly changes with a degree change due to thermoelastic martensitic transformation, and it is also known as a material that reversibly changes shape with a change in temperature due to thermoelastic martensitic transformation.
Nl, F@-Ni, Nt-kl, Nb-7%,
, Cu-Zn-8n, Cm-Zn-A1mCu-Zn,
Cu-8n, Fe-Pt, Fe-Be *F@-Mn
, In-s, Au-Cd, kf-Ztr and other alloys are materials with shape memory effect.

【Are known. When these alloys are heat-treated at a temperature higher than the reverse transformation end temperature Af to form the original shape, the temperature decreases by 11 degrees and when it becomes lower than the martensitic transformation start a degree Mm, the deformation starts and the martensitic transformation ends. The deformation stops when @fl1MtK is reached. When the temperature rises to 11 degrees Celsius and becomes higher than the starting temperature As of the reverse transformation a, it starts deforming again and returns to its original shape when the reverse transformation end temperature f' is appropriate (FIG. 1). Therefore, if a material that has been heat treated at a temperature higher than Af- to memorize its original shape is processed and deformed into a desired shape at a temperature lower than Mf, it will gradually recover to its original shape when i1 degrees exceeds Am. become. Alternatively, if the bias member is applied at a temperature lower than Mf without processing deformation to form a cylindrical shape, when the temperature reaches As or higher, it will overcome the load of the bias member and begin to recover to its original shape. do. These shape changes are reversible. Figure 2 shows the minimum AI and maximum reverse transformation temperature ht of the material made of shape memory alloy, and the temperature between 〒0. 〒2. T
The relationship between the amount of deformation and load in 3 is shown below. This is a typical characteristic curve diagram in which stress is linearly related to load and strain is directly proportional to the amount of deformation. temperature is am
When it changes from to Af. The material deforms by A when there is no load, and B under a constant load P.
When a bias member made of a metal material that does not have a shape memory effect is applied, it deforms by C. These deformation amounts A. B and C are always the same if the composition of the material is constant. Note that shape memory alloys exhibit superelasticity in the range between Af and Ms, and the degree hysteresis is approximately 20 for Ni-Ti, for example.
As can be seen from the fact that the bias member is significantly smaller than ordinary metal materials as it shows approximately 10°C at mu = c11, the bias member reduces the difference in the temperature at which material deformation starts due to this 1llf hysteresis Vsis, resulting in a temperature of 111 degrees It is also used to operate at a constant @ degree both when ascending and descending. l! In addition, as can be seen from the 2'' WA, the amount of deformation of shape memory alloys due to temperature changes is small in the high temperature range near AfK, and A
It is large in the low temperature range close to s. Therefore, the bias member is effective for stably maintaining the throttle valve of the vaporizer in an inoperative state during low temperatures. However, if the composition of the shape memory alloy used is appropriately selected, a bias member is not necessary. In the two-stage carburetor according to the present invention, a spring made of a shape memory alloy acts on the operating member of the negative pressure operating mechanism against negative pressure. This spring may be installed in place of a conventional spring made of conventional material, or may be used in conjunction with a spring made of conventional material as a biasing member. According to the present invention, first, only a spring made of a shape memory alloy acts on the actuating member. A spring made of a shape memory alloy and a spring made of a material without shape memory effect act on the second active member. As mentioned at the beginning, the purpose of the present invention is to prevent the secondary vaporizer from operating at low temperatures.
By utilizing the phase dislocation phenomenon associated with temperature changes in materials that have a shape memory effect, the operating members of the negative pressure operating mechanism are fixed below a certain temperature and made movable above a certain temperature. It is completely fixed at a certain temperature and becomes movable at a temperature higher than As. As described above, according to the present invention, by causing a spring made of a shape memory alloy to act on the manufacturing member of the negative pressure operation mechanism,
Even if the actuating member is fixed by this spring and a high negative pressure is applied below a certain degree, the throttle valve of the secondary carburetor will not operate. For this reason, even if the secondary carburetor is activated immediately after starting in cold weather, the air-fuel mixture will be supplied only from the primary carburetor and no car knock will occur, and even if the engine is not sufficiently warmed up. There will also be no inconvenience of putting a huge burden on the body and affecting its lifespan. Springs made from shape memory alloys have the advantage of higher operating reliability (and greater deformation) than bimetals that change shape with heat, and can be easily replaced with conventional springs or added to conventional devices. The purpose can be achieved, and the spring material composition and original shape. By selecting the shape after processing deformation, spring diameter, pitch, etc., the operation start temperature of the manufactured member and the suction distance due to negative pressure can be varied. [Embodiment 1] (Fig. 3) A secondary vaporizer disposed in parallel with the primary vaporizer P A lever 3 fixed to the throttle valve shaft 2 of the throttle valve 1 of the device S and @6 fixed to the center of the operating member 5 of the negative pressure operating mechanism 4 and extending in the operating direction are connected by a connecting rod 7. A negative pressure chamber 8 that sucks the operating member 5 of the negative pressure operation-4 is connected to a negative pressure passage 9 that applies a composite negative pressure of the venturi negative pressure of the primary vaporizer P and the venturi negative pressure of the secondary vaporizer S. It also has a built-in coiled spring 10 made of a shape memory alloy.This spring IO is heat treated at a higher temperature than Af to memorize its original shape, and then stretched at a lower temperature than Mm. The actuating member 5 is fixed at low temperatures so that even if a high negative pressure is applied, it will not be drawn toward the negative pressure chamber 8. When the temperature rises, the spring 10 gradually contracts. The movement distance of the actuating member 5 gradually increases. [Example 2] (Fig. 4) A spring made of the same shape memory alloy as described above is installed in the negative pressure chamber 8.
and a coiled spring 11 made of a material without shape memory effect are built in concentrically and push the actuating member 5. In this example. The spring 10 fixes the actuating member 5 during other operations, but it rapidly contracts when the temperature exceeds a certain temperature, and thereafter the fK actuating member 5 is suctioned and moved until the force of the spring 11 and the negative pressure are balanced. [Implementation fla] (Fig. 5) A coiled spring 12 made of a material that does not have a shape memory effect is built into the negative pressure chamber 8, and a coiled spring 12 made of a shape memory alloy placed in the envelope is built in. The actuating member 5 is pushed in opposite directions by opposing the spring 13. The spring 13 is heat-treated at a higher temperature than Af to memorize its original shape, and then compressed and deformed at a lower temperature than Mt.As a bias member, the spring 12 of the negative pressure chamber 8 is a conventional It has a large tension compared to the springs used. At low temperatures, the spring 13 contracts and the tension of the spring 12 is fully applied to the actuating member 5, fixing it, but at temperatures above a certain degree, it gradually expands toward its original shape, and the tension of the spring 12, however, Lower the actuating member 5 to the OT operating state.

[Brief explanation of drawings]

Figures 1 and 2 are diagrams showing the characteristics of shape memory alloys, Figure 3 is a vertical sectional view showing an embodiment of the present invention, and Figures 4 and 5 are diagrams showing different embodiments of the present invention. It is a vertical cross-sectional partial view showing P...-Ku vaporizer, S...Secondary vaporizer-
21... Throttle box, 2... Throttle valve shaft, 4
... Negative pressure operating mechanism, 5... Operating member,
8...Negative pressure chamber, 10°11.1-2.13...
...Spring. Agent Mutsumi Nozawa Aki

Claims (4)

[Claims] (1) A spring made of a shape memory alloy is attached to the operating member of the negative pressure operating mechanism connected to the throttle valve shaft of the secondary carburetor and operated by venturi negative pressure to fix the operating member below a certain temperature. A negative pressure type two-stage vaporizer characterized by being activated. (2) A coiled spring made of a shape memory alloy is built into the negative chamber where the venturi negative pressure that attracts the operating member is introduced, and this spring retains its original shape at a low temperature compared to the original shape memorized at a high temperature. Claims (negative pressure type two-stage vaporizer described in IIK) which are processed and deformed by stretching. (3) A coiled spring made of a shape memory alloy and a coiled spring made of a material that does not have a shape memory effect are built into the negative chamber where the venturi negative pressure that attracts the operating member is introduced. . 12. The negative pressure type two-stage vaporizer according to claim 11, wherein the spring made of the shape memory alloy is processed and deformed by stretching at a low temperature from an original shape memorized at a high temperature. (4) A coil made of a material that does not have a shape memory effect, which is built in the negative chamber where the venturi negative pressure is introduced to attract the actuating member, and a coil made of a shape memory alloy, which is arranged opposite to the shaped spring 11. A shaped spring is provided to sandwich an actuating member, and the spring made of the shape memory alloy is compressed and deformed at a low temperature with respect to the original shape memorized at a high temperature. Negative pressure type two-stage vaporizer described in tl K.