JP2958592B2 - Fuel injection amount / injection rate measuring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection amount / injection rate measuring device for measuring a fuel injection amount / injection rate from a fuel injection valve in an internal combustion engine.

[0002]

2. Description of the Related Art A conventional fuel injection rate measuring device is disclosed in, for example, Japanese Patent Application Laid-Open No. 64-63649. It is of the Zeuch type and is based on ΔP = K · ΔV / V. That is, if there is a small volume change ΔV of the fluid with respect to the fluid in the constant volume V, the pressure change Δ proportional to the volume change rate ΔV / V of the fluid is set as the volume elastic modulus K of the fluid as a proportional constant.
P occurs.

Therefore, fuel is injected from a fuel injection valve into a fuel chamber filled with fuel, and the pressure change ΔP
Is measured, the fuel injection amount ΔV is obtained from the above equation, and further, the fuel injection rate is calculated therefrom.

[0004]

In the fuel injection rate measuring device according to the prior art described above, ΔP = K · ΔV / V
ΔV = ΔP · V / K is measured based on
At this time, since the bulk modulus K of the fuel varies depending on the temperature and pressure of the fuel and the type of the fuel, it is necessary to perform calibration every time the pressure change ΔP is measured. The present invention provides a fuel injection rate measurement device that does not require the calibration of the bulk modulus, regardless of the bulk modulus of the fuel, which is a function of the temperature, pressure, type of fuel, and the like.

[0005]

The fuel injection amount of the present invention
The injection rate measuring device is configured such that a closed container filled with fuel is separated into a first chamber and a second chamber separated by a diaphragm,
An injection nozzle for injecting fuel into the first chamber is attached to the closed container, and a non-contact gap sensor that is opposed to the diaphragm in the second chamber and detects a displacement amount of the diaphragm is attached to the closed container. Are connected so as to input a detected displacement signal to a measuring and calculating device which detects the displacement of the diaphragm and calculates the fuel injection amount based on the equation (1).

Further, the measurement arithmetic unit calculates the fuel injection rate based on the equation (2) from the amount of displacement of the diaphragm obtained from the detected displacement signal and the time. Fuel injection amount ΔV = D · ΔL · (VA ₀ + VB ₀ ) / VB ₀ (1) Fuel injection rate d inj / dt = d [ρ · ΔL · D (VA ₀ + VB ₀ ) / VB ₀ ] / dt (2) Initial value of actual volume of one chamber: VA ₀ Initial value of actual volume of second chamber: VB ₀ Effective area of diaphragm: D Diaphragm displacement: ΔL Density of liquid: ρ Time: t

[0007]

When measuring with the above-described fuel injection amount / injection rate measuring device, first, the fuel is filled in the first chamber and the second chamber of the closed container, and the first and second chambers filled with the fuel are sealed. I do.

Next, fuel injection is performed from the ejection nozzle toward the first chamber. Due to the fuel injection, the pressure in the first chamber increases and becomes larger than the pressure in the second chamber, and the diaphragm is displaced toward the non-contact gap sensor in the second chamber, and the gap changes between the diaphragm and the non-contact gap sensor. That is, the displacement amount ΔL of the diaphragm is detected by the non-contact gap sensor. The detected displacement signal is input to the measuring and calculating device, where the following formula is calculated based on the diaphragm displacement amount ΔL and time t obtained from the detected displacement signal, and the fuel injection amount ΔV and the fuel injection rate are calculated. d inj / dt is calculated.

ΔV = D · ΔL · (VA₀+ VB₀) / VB₀  d inj / dt = d [ρ · ΔL · D (VA₀+ VB₀) /
VB₀] / Dt However, initial value of actual volume of the first chamber: VA₀Room 2 fruit
Initial volume: VB₀ Diaphragm effective area: D Diaphragm displacement
Amount: ΔL Liquid density: ρ Time: t

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A fuel injection amount / injection rate measuring apparatus according to an embodiment of the present invention will be described with reference to the drawings. First, the fuel injection amount
The principle of the injection rate measuring device will be described. Referring to FIG. 2, a second sealed container 22 is fixed to the first sealed container 21 so as to protrude into the first sealed container 21, and a part of the wall surface of the second sealed container 22 is fixed to the diaphragm. 23. Then, the first closed container 21
An ejection nozzle 24 for ejecting a liquid from the outside into the first closed container 21 is attached to the wall surface of the second closed container 22.
A non-contact gap sensor 25 is provided so as to face the diaphragm 23, detects a displacement amount of the diaphragm 23, and outputs a detection signal to the outside. The liquid ejected from the ejection nozzle 24 is already filled in the first closed container 21 and the second closed container 22.

In the above apparatus, the actual volume of the first closed container: VA The initial value of the actual volume of the first closed container: VA ₀ The actual volume of the second closed container: VB The initial value of the actual volume of the second closed container: VB ₀ Liquid injection amount: ΔV Diaphragm effective area: D Diaphragm displacement amount: ΔL Actual volume change amount of the second closed container due to diaphragm displacement:
Δv Density of liquid: ρ Time: t Liquid ejection rate: d inj / dt

Therefore, it is assumed that the liquid having the measured injection amount ΔV is injected from the injection nozzle 24 into the first closed container 21.
Then, the pressure in the first closed container 21 increases, and the diaphragm 23 is pressed and displaced by ΔL into the second closed container, and the displacement is detected by the non-contact gap sensor 5. As a result, the actual volume initial value VB ₀ of the second closed container in the second closed container 22 changes.

Based on the above, the injection amount ΔV and the liquid injection rate d inj are calculated as follows. Injection amount ΔV
Pressure rise in the closed container when the liquid of
And the volume elastic moduli of the liquids in the first closed container and the second closed container are K ₁ and K ₂ , respectively. Here, assuming that K ₁ = K ₂ = K, ΔP = K · ΔV / (VA ₀ + VB ₀ ) (1) ΔP = K · Δv / VB _0. (2) From the equations (1) and (2), ΔV / (VA ₀ + VB ₀ ) = Δv / VB ₀ ^{ΔV = Δv · (VA} 0 ^{+ VB} 0 ^{) / VB} 0 ⁽³⁾ , Δv = D · ΔL (4)

Therefore, the measured injection amount ΔV is given by (3)
From the equation and the equation (4), the following equation is obtained. ΔV = D · ΔL · (VA ₀ + VB ₀ ) / VB ₀ (5) Further, the liquid ejection rate d inj is as follows. d inj / dt = dΔV · ρ / dt = d [ρ · D · ΔL · (VA ₀ + VB ₀ ) / VB ₀ ] / dt (6)

FIG. 1 shows a fuel injection amount / injection rate measuring device based on the above principle. In the fuel injection amount / injection rate measuring device shown in FIG. 1, a cylindrical partition 2 is formed so as to protrude from an inner surface of an airtight container 1. The diaphragm 3 is in close contact with the opening end face of the cylindrical partition 2, and the inside of the cylindrical partition 2 is sealed by the diaphragm 3. Therefore, the inside of the closed container 1 is separated via the diaphragm 3 into a first chamber 4 outside the cylindrical partition 2 and a second chamber 5 inside the cylindrical partition 2.

The first chamber 4 is externally provided on the wall surface of the closed container 1.
An injection nozzle 6 for injecting fuel is mounted therein, and a non-contact gap sensor 7 protruding from the outside into the second chamber 5 and facing the diaphragm 3 is mounted.
The non-contact gap sensor 7 is connected to an external measurement operation / control device (not shown) via a signal line L, detects the amount of displacement of the diaphragm 3, and inputs a detection signal to the measurement operation / control device. I have.

The measurement calculation / control device includes a first chamber 4
, The actual volume initial value VA _{0 of} the first chamber 4, the actual volume VB of the second chamber 5, the actual volume initial value VB _{0 of} the second chamber 5, the effective area D of the diaphragm 3 and the liquid density ρ It is input and stored in advance.

A first through hole 8 communicating with the first chamber 4 is formed on the wall surface of the closed casing 1, and the first through hole 8 is connected to a discharge line 10 through which a high-speed discharge valve 9 is interposed. At the same time, a second through hole 11 that connects the second chamber 5 to the first chamber 4 and a third through hole 12 that communicates the second chamber 5 to the outside of the closed casing 1 are formed in the cylindrical partition wall 2. . It is screwed in the axial direction to the cylindrical partition wall 2 and externally operated to open and close the third through hole 12 like the first vent valve 13 which is externally operated to open and close the second through hole 11. A second vent valve 14 is provided. The high-speed discharge valve 9 opens and closes at high speed in response to an open / close signal from a measurement calculation / control device.

In the measurement calculation / control device, the following signals are input and processed in the fuel injection timing from the injection nozzle 6 and the fuel discharge from the high-speed discharge valve 9 performed at the timing shown in FIG. It is supposed to be.

That is, an angle pulse signal transmitted for each unit rotation angle of the fuel injection cam, which is the basis of the fuel injection timing, is input (see FIG. 3A). One reference pulse, which is transmitted at a predetermined phase every rotation by the rotation of the fuel injection cam, is input (see FIG. 3B). After the reference pulse angle pulses a predetermined number by the rotation of the fuel injection cam, the valve opening signal of the high-speed exhaust valve 9 is input words from the reference phase at T ₁ of the predetermined time after the phase time T ₃ (Fig. 3
(C)).

[0022] After the reference pulse by the rotation of the fuel injection cam angle pulse a predetermined number, i.e., fuel injection from the injection nozzle 6 starting from the reference phase at T ₁ in the phase when T ₂ of the predetermined time after performed, the The resulting displacement ΔL of the diaphragm 3 is detected by the non-contact gap sensor 7, and the displacement signal is input (see FIG. 3D). The displacement signal of the diaphragm 3 in FIG. 3D is differentiated to obtain a differential value (dΔL / dt) (see FIG. 3E).

In the measurement by the above-described fuel injection amount / injection rate measuring device, the high-speed discharge valve 9 is normally in a closed state, and first, the first air release valve 13 and the second air release valve 14 are opened. Fuel is supplied from the injection nozzle 6 into the first chamber 4. The fuel passes the air in the first chamber 4 through the second through hole 11 and the second chamber 5.
The first chamber 4 is filled while being discharged to the outside through the third through hole 12, and the air in the second chamber 5 is similarly discharged through the second through hole 11 to fill the second chamber 5. Therefore, the first air release valve 13 and the second air release valve 14 are closed, and the first chamber 4 and the second
The communication between the first chamber 4 and the second chamber 5 filled with fuel is closed by shutting off the flow to the chamber 5 and the flow to the outside of the second chamber 5.

[0024] Next the fuel injection to measure the ejection nozzle 6 to the reference phase at T ₁ in the phase when T ₂ of the predetermined time after toward the first chamber 4 is performed. Due to the fuel injection, the pressure in the first chamber 4 increases and becomes larger than the pressure in the second chamber 5, and the diaphragm 3 moves toward the non-contact gap sensor 7 in the second chamber 5 during fuel injection. The displacement (see FIG. 3D) causes a change in the gap between the diaphragm 3 and the non-contact gap sensor 7, that is, the displacement ΔL of the diaphragm 3.
, And the displacement signal is input to the measurement calculation / control device. The displacement amount ΔL of the diaphragm 3 is differentiated to obtain a differential value (dΔL / dt) (FIG. 3E).
reference).

[0025] Then the opening signal of the reference from the phase time T ₁ of the predetermined time after the phase time T _3, high-speed exhaust valve 9 is opened at a high speed, the fuel under pressure in the first chamber 4, the discharge pipe Exhausted from the passage 10, the pressure in the first chamber 4 drops to be equal to the pressure in the second chamber 5, so that the diaphragm 3 moves away from the non-contact gap sensor 7 (see FIG. 3D). ).

In the measurement calculation / control device, ΔV = D · ΔL · (VA ₀ + VB ₀ ) / VB ₀ is calculated based on the input displacement amount ΔL of the diaphragm 3, and the injection amount ΔV is calculated.

The differential value (dΔL /
dt), the injection rate d inj / dt = d [ρ · D · ΔL · (VA ₀ + VB ₀ )
/ VB ₀ ] / dt is calculated, and the injection rate d inj / dt is calculated.

[0028]

According to the fuel injection amount / injection rate measuring device of the present invention, the fuel injection amount is calculated from the volumes of the first and second chambers, the effective area of the diaphragm and the displacement of the diaphragm. Since the modulus is calculated by adding the density of the fuel to them, the bulk modulus of the fuel, which is a function of the temperature, the pressure, the type of the fuel, and the like, is not related. Therefore, if the temperature of the fuel is constant in the measurement of the fuel injection amount and the injection rate,
Calibration of bulk modulus is not required, work efficiency is improved, and measurement accuracy is also improved.

[Brief description of the drawings]

FIG. 1 is a sectional view of a fuel injection amount / injection rate measuring device according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating the principle of a fuel injection amount / injection rate measuring device according to an embodiment of the present invention.

FIG. 3 is a fuel injection timing chart of the fuel injection amount / injection rate measuring device according to the embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Closed container 2 Cylindrical partition 3 Diaphragm 4 1st chamber 5 2nd chamber 6 Injection nozzle 7 Non-contact gap sensor 8 1st through-hole 9 High-speed discharge valve 10 Drain pipe 11 2nd through-hole 12 3rd through-hole 13th 1 vent valve 14 2 vent valve 14

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) F02M 65/00 302-303 G01F 3/20

Claims (2)

(57) [Claims] An airtight container filled with fuel is separated into a first chamber and a second chamber separated by a diaphragm, and an injection nozzle for injecting fuel into the first chamber is attached to the airtight container. At the same time, a non-contact gap sensor that is opposed to the diaphragm in the second chamber and detects the amount of displacement of the diaphragm is attached. The non-contact gap sensor detects the amount of displacement of the diaphragm, and calculates the fuel injection amount based on the following equation. A fuel injection amount measuring device connected to input a detected displacement amount signal to the measurement arithmetic device. Fuel injection amount ΔV = D · ΔL · (VA ₀ + VB ₀ ) / VB
₀ However, initial value of actual volume of the first chamber: VA ₀ Initial value of actual volume of the second chamber: VB ₀ Effective diaphragm area: D Diaphragm displacement: ΔL 2. An airtight container filled with fuel is separated into a first chamber and a second chamber separated by a diaphragm, and an injection nozzle for injecting fuel into the first chamber is attached to the airtight container. At the same time, a non-contact gap sensor facing the diaphragm in the second chamber and detecting the amount of displacement of the diaphragm is attached, the non-contact gap sensor detects the amount of displacement of the diaphragm, and the injection time and the diaphragm obtained from the detected displacement signal. A fuel injection rate measurement device connected to input a detected displacement signal to a measurement arithmetic device that calculates a fuel injection rate based on the following equation from the displacement amount. Fuel injection rate d inj / dt = d [ρ · ΔL · D (VA ₀ +
VB ₀ ) / VB ₀ ] / dt where initial value of the actual volume of the first chamber: VA ₀ initial value of the actual volume of the second chamber: VB ₀ Effective diaphragm area: D Displacement of the diaphragm: ΔL Density of liquid: ρ Time: t