Background technique
Characteristics such as exhaust braking valve is made simply because its braking force is bigger, and cost is low have been widely used on the high-power commercial car.When commercial car is travelled in the road surface situation preferably on the road, when needing to slow down, the independent exhaust braking valve that uses just can reach gratifying braking effect, and when travelling in the bad area of road conditions, for example travel when some often have the mountain area on long sharp decline road, generally exhaust brake and engine braking are united use, to improve braking force.
Existing exhaust braking valve kind is a lot, and they normally are made up of parts such as butterfly valve, valve body and cylinders, are installed in the gas exhaust manifold back of motor, or are installed in the pressurized machine back.
When exhaust braking valve is worked, the rotation of cylinder control butterfly valve, outlet pipe is blocked, exhaust back pressure in the outlet pipe increases, piston motion is produced resistance, and this resistance is by bent axle, and the power train of automobile etc. passes to wheel, form braking force, thereby played the effect of giving motor and car deceleration.
When exhaust braking valve is worked, can set up higher exhaust back pressure, the size of exhaust back pressure is relevant with engine speed, and engine speed is big more, pours in the outlet pipe with regard to having many more exhausts, and exhaust back pressure also just increases thereupon.Exhaust back pressure is big more, and the braking force of motor is just big more, so, by increasing the mode of exhaust back pressure, can improve the braking force of motor.But, exhaust back pressure can not unrestrictedly increase, because exhaust back pressure is big more, the heat of motor is just big more, because the effect of exhaust braking valve, heat release is slowed down, especially when the high rotating speed of motor, exhaust back pressure surpasses the limit value that motor can bear probably, and motor will be in superheat state, this can give the life-span of motor, and power character etc. are brought very big infringement.This problem is more obvious on the motor that the exhaust braking valve that high back pressure can be provided is housed.In addition, when the butterfly valve of exhaust braking valve cuts out, exhaust back pressure in the outlet pipe increases, exhaust back pressure acts on the exhaust valve back cone, when exhaust back pressure pressure surpasses making a concerted effort of exhaust valve initial tension of spring and cylinder pressure, the secondary opening phenomenon can appear in exhaust valve, will be to the component of distribution device, and especially exhaust valve causes bigger infringement.
Specific embodiments
Describe concrete technological scheme of the present utility model in detail below in conjunction with accompanying drawing.
Embodiment 1:
As Fig. 1 and Fig. 3 as can be known, high back pressure exhaust brake valve, it includes cylinder 1, exhaust braking valve 2, cylinder 1 is installed together with exhaust braking valve 2, it is characterized in that: it also comprises pressure-limit valve 3 and connecting tube 4, pressure-limit valve 3 is connected with exhaust braking valve 2 by connecting tube 4, has exhaust port 5 on the pressure-limit valve 3.
Pressure-limit valve provided by the utility model, it is by valve body a7 and valve body b8, flap 9, adjust bolt 10, nut 11, spring seat 12, spring 13, exchange hole 15, dust guard 14 is formed, spring seat 12, spring 13, flap 9 is installed in the valve body a7 successively, valve body a7 and valve body b8 are installed together, flap 9 is sealed on the valve body b8, an end of adjusting bolt 10 contacts with spring seat 12, nut 11 is installed in the other end of adjusting bolt 10, side at valve body a7 has exchange hole 15 in the middle part partially, the end at exchange hole 15 is equipped with dust guard 14, has exhaust port 5 on the top of valve body a side.
Pressure-limit valve valve body a7 is connected with bolt 16 with valve body b8, flap 9 tightly is sealed on the valve body b8 under the pretightening force effect of spring 13, why valve body is made two-part, the one, for easy to process, the surface of contact of flap 9 and valve body b8, promptly sealing surface needs the higher grinding of precision, to guarantee sealing, the 2nd, in order to enlarge exhaust space, so that gas is discharged rapidly; Adjust bolt 10, nut 11 and spring seat 12 and be used for the pretightening force of Regulation spring 13, exchange hole 15 has two effects, the one, the gas of discharge valve body a7, make it consistent with atmospheric pressure, the 2nd, for the heat exchange of reinforcement spring 13, reduce the operating temperature of spring 13 with atmosphere, guarantee spring performance, the end at exchange hole 15 has individual dust guard 14, and purpose is for preventing that sand, dust etc. from entering into the spring active chamber of valve body a7, protection spring 13; Flap 9 contacts an end with spring have a chimb 18, and chimb 18 is complementary with spring, prevents that flap 9 from opening excessive and excess compression spring 13.
When exhaust braking valve was worked, cylinder 1 worked, and the rotation butterfly valve is to closed position, and outlet pipe gets clogged, and at this moment, because engine speed is lower, exhaust back pressure is also lower, and the exhaust pressure that enters pressure-limit valve 3 by connecting tube 4 is not enough to open pressure-limit valve.Rising along with the rotating speed of motor, exhaust back pressure also raises gradually, when near the maximum exhaust back pressure limit value that starts that function bears, pressure-limit valve 3 is opened, and discharge into the atmosphere by exhaust port 5, should be noted that herein, because during exhaust brake work, the motor fuel cut-off, so the waste gas of discharging is hot air, can be according to the layout needs of motor, pressure-limit valve 3 is arranged in the place that ventilation better and does not on every side have thermo-labile part, like this hot air of Pai Chuing can large size and atmosphere carry out heat exchange, delivery temperature reduces rapidly, can not cause damage to other part.
Embodiment 2:
As Fig. 2 and Fig. 4 as can be known, pressure-limit valve 3 of the present utility model is connected with exhaust braking valve 2 with connecting tube 6 by connecting tube 4, and connecting tube 4 is for pressure-limit valve 3 provides pressure source, and connecting tube 6 provides exhaust source for pressure-limit valve 3.The advantage of this structure is that a stable and pressure source more accurately can be provided, and makes the calculating of spring and choose to become simple.
Pressure-limit valve of the present utility model 3 it by valve body a7 and valve body b8, flap 9, adjust bolt 10, nut 11, spring seat 12, spring 13 and form, spring seat 12, spring 13, flap 9 are installed in the valve body a7 successively, valve body a7 and valve body b8 are installed together, flap 9 is sealed on the valve body b8, an end of adjusting bolt 10 contacts with spring seat 12, nut 11 is installed in the other end of adjusting bolt 10, the middle part has pressure entrance 17-2 partially in the side of valve body b8, has pressure port 17-1 at the end face of valve body b.
Pressure-limit valve valve body a7 and valve body b8 are installed together, flap 9 tightly is sealed on the valve body b8 under the pretightening force effect of spring 13, why valve body is made two-part, the one, for easy to process, flap 9 has two sealing surfaces, the one side of the valve body b8 of the exhaust port that sealing surface 20 sealed valve body b8 and valve body a7 form, the pressure port 17-1 of sealing surface 19 sealed valve body b8, between two sealing surfaces LAP is arranged, at the valve body b8 of this section stroke correspondence is pressure entrance 17-2, flap 9 contacts an end with spring have a chimb 18, and chimb 18 is complementary with spring 13, prevents that flap 9 from opening excessive and excess compression spring 13; The surface of contact of flap 9 and valve body b8, promptly sealing surface needs the higher grinding of precision, with the assurance sealing, the 2nd, in order to enlarge exhaust space, so that gas is discharged rapidly; Adjust bolt 10, nut 11 and spring seat 12 and be used for the pretightening force of Regulation spring 13.
Embodiment 3:
As shown in Figure 3, pressure-limit valve 3 of the present utility model is made one with exhaust braking valve 2, it is by the valve body 22 of exhaust braking valve and the valve body 7 of pressure-limit valve, spring 13, spring seat 12, nut 11, adjust screw 10, flap 9, butterfly valve 24, inlet end 17, exhaust end 23, bypass path 25 is formed, spring seat 12, spring 13, flap 9 is installed in the valve body 7 of pressure-limit valve successively, the valve body 2 of flap 9 sealed pressure-limiting valves, valve body 22 at exhaust braking valve has bypass path 25, the valve body 7 of pressure-limit valve and the valve body 22 of exhaust braking valve are installed together, an end of adjusting bolt 10 contacts with spring seat 12, and nut 11 is installed in the other end of adjusting bolt 10.
The valve body 7 of pressure-limit valve 3 is an one with the valve body 22 of exhaust braking valve, the valve body 22 of exhaust braking valve has bypass logical 25, the inlet of bypass path communicates with the exhaust entrance 17 of the outlet pipe of exhaust braking valve and by pressure-limit valve 3 sealings, the outlet of bypass path communicates with the exhaust outlet 23 of the outlet pipe of exhaust braking valve.
This pressure-limit valve also can be made separately.
Structure of the present utility model is not limited to said structure, and its essence is to install a pressure-limit valve additional to the engine exhaust and brake valve, perhaps directly pressure-limit valve and exhaust braking valve is manufactured one.The effect of this pressure-limit valve is that after exhaust braking valve butterfly valve 24 cuts out the exhaust back pressure of control engine interior is no more than the threshold limit value of starting function to bear.
Above the utility model embodiment is described in detail in conjunction with the accompanying drawings, but the utility model is not limited to the foregoing description, as long as all belong to the utility model without prejudice to the utility model notion and other mapping modes of not exceeding the utility model scope.