CN201351540Y - High pressure common rail diesel engine common rail oil pressure reduction test connection device - Google Patents

Abstract

The utility model relates to a high pressure common rail diesel engine common rail oil pressure reduction test connection device; a hydraulic pressure reduction connection device is connected with a common rail body through threads via a high-pressure cavity and is connected with an oil pressure sensor through threads via a low pressure cavity, and the high pressure cavity is connected with the low pressure cavity through a pressure reduction piston. High pressure diesel fuel inside the common rail body is applied onto the pressure reduction piston through the high pressure cavity, so that the pressure reduction piston applies pressure onto the low pressure cavity; when the force which is acted by oil pressure of the low pressure cavity onto the pressure reduction piston is equal to that is acted by the oil pressure of the high pressure cavity onto the pressure reduction piston, the pressure reduction piston is balanced; and since the diameter of the piston on the low pressure cavity end is more than that of the piston on the high pressure cavity end, the pressure inside the low pressure cavity is smaller than that inside the high pressure cavity, so that the pressure which is measured by the low pressure sensor of the low pressure cavity can be utilized to calculate the common rail pressure of the high pressure cavity, thereby reducing the pressure measuring range of the electric controlled high pressure common rail diesel engine high pressure oil pressure sensor.

Description

High pressure co-rail diesel machine common rail fuel pressure decompression test connecting apparatus

Technical field

The utility model relates to a kind of device that reduces Electrocontrolled high-pressure common rail diesel engine high-pressure fuel pressure transmitter pressure measurement range.

Background technique

In diesel engine high-pressure co-rail formula fuel injection system, the unlatching of oil sprayer relies on the solenoid valve of ECU (Electrical Control Unit) control to realize, do not rely on fuel pressure, so, the height of rail oil pressure has determined the height of injection pressure altogether, and the height of injection pressure is to be decided by the requirement of ECU (Electrical Control Unit) according to diesel engine condition.For accurate control is total to the rail oil pressure, after the high pressure fuel of high-pressure fuel-feed pump generation is admitted to common rail, measure the actual fuel pressure that is total in the rail by the oil pressure sensor that is arranged on the common rail, provide feedback information to ECU (Electrical Control Unit).Generally speaking, the oil pressure that the high pressure co-rail diesel machine is total in the rail body is very high (usually 120 ~ 200MPa), require used fuel pressure transmitter to have high voltage endurance capability, need the common rail pressure sensor of configure dedicated just can satisfy the demands, and the cost of high pressure sensor is the several times price of usual pressure sensor.

Summary of the invention

High pressure co-rail diesel machine high pressure fuel pressure decompression test connecting apparatus described in the utility model, utilize the hydro-cushion principle, by acting on the equilibrium of forces effect on the decompression piston (3), reach and reduce the purpose of measuring high pressure co-rail diesel machine high pressure fuel pressure transducer range.

The utility model is set up hydraulic pressure decompression connection set (as Fig. 2) between the common rail body (7) of high pressure co-rail diesel machine and oil pressure sensor (1), hydraulic pressure decompression connection set passes through screw thread rail body (7) connection together via hyperbaric chamber (4), be connected with oil pressure sensor (1) by screw thread via low-pressure cavity (2), hyperbaric chamber is connected with low-pressure cavity by decompression piston (3).High-pressure diesel promotion decompression piston (3) in the rail body moves to low-pressure cavity (2) direction altogether, and decompression piston finally is in state of equilibrium under the acting in conjunction of hyperbaric chamber (4) and low-pressure cavity (2) oil pressure.The area that utilizes low-pressure cavity and hyperbaric chamber piston is than being implemented in the reduction in proportion of low-pressure cavity fuel pressure, to calculate the hyperbaric chamber oil pressure again be common rail pressure to the pressure of measuring low-pressure cavity with regard to available low pressure sensor like this, and its effect is to have reduced the range of measuring common rail pressure sensor.

Mechanics Calculation is according to as follows:

When decompression piston is in state of equilibrium, the pressure dependence of high low pressure oil pocket:

${\mathrm{<figure-callout\; id="1"\; label="P"\; filenames="Y2008201071310005H1.png"\; state="\{\{state\}\}">P</figure-callout>}}_1\&times;\frac{{\mathrm{\&pi;<figure-callout\; id="2"\; label="d"\; filenames="Y2008201071310005H1.png,Y2008201071310006H1.png"\; state="\{\{state\}\}">d</figure-callout>}}^2}{4}={\mathrm{<figure-callout\; id="2"\; label="P"\; filenames="Y2008201071310005H1.png,Y2008201071310006H1.png"\; state="\{\{state\}\}">P</figure-callout>}}_2\&times;\frac{{\mathrm{\&pi;<figure-callout\; id="2"\; label="D"\; filenames="Y2008201071310005H1.png,Y2008201071310006H1.png"\; state="\{\{state\}\}">D</figure-callout>}}^2}{4}---\left(1\right)$

Promptly $\frac{P_1}{{\mathrm{<figure-callout\; id="2"\; label="P"\; filenames="Y2008201071310005H1.png,Y2008201071310006H1.png"\; state="\{\{state\}\}">P</figure-callout>}}_2}=\frac{D^2}{d^2}---\left(2\right)$

Can draw the pressure of low-pressure cavity according to (2) formula:

${\mathrm{<figure-callout\; id="2"\; label="P"\; filenames="Y2008201071310005H1.png,Y2008201071310006H1.png"\; state="\{\{state\}\}">P</figure-callout>}}_2=\frac{d^2}{{\mathrm{<figure-callout\; id="2"\; label="D"\; filenames="Y2008201071310005H1.png,Y2008201071310006H1.png"\; state="\{\{state\}\}">D</figure-callout>}}^2}\&times;P_1---\left(3\right)$

Shown in (3) formula, the oil pressure ratio in high and low pressure chamber and its diameter duplicate ratio are inversely proportional to, under the situation of low-pressure cavity end piston diameter (D) greater than hyperbaric chamber end piston diameter (d), the low-pressure cavity oil pressure that low pressure sensor records is less, realizes that common rail pressure is reduced the back adopts the lower range pressure transducer to calculate the purpose of common rail pressure.

Decompressor described in the utility model is simple in structure, working stability, and good reliability, installing hydraulic pressure decompression connection set additional does not have too high required precision, cheap for manufacturing cost.

Description of drawings

Fig. 1 is an overall structure schematic representation of the present utility model.

Fig. 2 is a hydraulic pressure decompression connection set schematic representation of the present utility model.

1. oil pressure sensor, 2. low-pressure cavity, 3. decompression piston, 4. hyperbaric chamber, 5. decompression piston cover, 7. rail body altogether

P ₁The hyperbaric chamber oil pressure

D hyperbaric chamber end piston diameter

P ₂The low-pressure cavity oil pressure

D low-pressure cavity end piston diameter

Embodiment

Consult Fig. 1, the common rail body (7) of high pressure co-rail diesel machine is connected with hyperbaric chamber (4) by screw thread, and hyperbaric chamber is connected with low-pressure cavity by decompression piston (3), and low-pressure cavity (2) is connected with pressure transducer by screw thread.High-pressure diesel in the rail body is applied on the decompression piston (3) by hyperbaric chamber (4) altogether, decompression piston is exerted pressure to low-pressure cavity (2), when low-pressure cavity (2) and hyperbaric chamber (4) oil pressure the power on the decompression piston (3) of acting on equated, decompression piston was in state of equilibrium.According to the mechanical equilibrium principle, the oil pressure ratio in high low pressure chamber and its diameter duplicate ratio are inversely proportional to, can utilize low-pressure cavity pressure that low pressure sensor (1) measures by ECU (Electrical Control Unit) according to known decompression piston diameter than the fuel pressure that calculates in the high-pressure common rail, low-pressure cavity (2) end piston diameter (D) is bigger than hyperbaric chamber (4) end piston diameter (d), has then realized reduction high pressure co-rail diesel machine common rail fuel pressure sensor pressure measurement range.

Claims (3)

1. high pressure co-rail diesel machine common rail fuel pressure decompression test connecting apparatus is characterized in that this device mainly is made up of decompression piston cover, decompression piston, hyperbaric chamber, low-pressure cavity, and hyperbaric chamber overlaps with decompression piston by decompression piston and is connected with low-pressure cavity.

2. high pressure co-rail diesel machine common rail fuel pressure decompression test connecting apparatus according to claim 1, the testing apparatus that it is characterized in that reducing pressure, is connected with oil pressure sensor by screw thread via low-pressure cavity by screw thread rail body connection together via hyperbaric chamber.

3. high pressure co-rail diesel machine common rail fuel pressure decompression test connecting apparatus according to claim 1 is characterized in that hyperbaric chamber end piston diameter is less than low-pressure cavity end piston diameter.

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