JP6404639B2 - Fuel flow measurement device - Google Patents

Description

  The present invention relates to a fuel flow rate measuring device used for evaluating the amount of fuel consumed by an internal combustion engine.

  Some conventional fuel flow measurement devices are connected to an internal combustion engine and can simulate fuel consumption and the like while simulating substantially the same state as an actual vehicle. This is configured so that a change in the flow rate of the fuel generated by the internal combustion engine sucking in the fuel is measured by a Coriolis flow meter.

  By the way, at the development site of an internal combustion engine, for example, there is a demand for capturing changes in the fuel flow rate within a very short time that occurs with a single injection amount of an injector. In order to meet such a demand, it is necessary to further improve the responsiveness of the Coriolis flowmeter in the fuel flow rate measuring device.

  In order to improve the responsiveness of the Coriolis flow meter 4A, in Patent Document 1, as shown in FIG. 7, the pump 2A, the upstream pressure gauge 3A, the Coriolis flow meter 4A, and the downstream pressure gauge 5A are sequentially inserted into the flow path 1A from the upstream side. A flow control system 100A is proposed in which a flow control valve 7A is provided and the control unit 6A controls the pump 2A and the flow control valve 7A based on the outputs of the pressure gauges 3A and 5A. The control unit 6A allows the pump 2A so that the measured differential pressure ΔP measured by the upstream pressure gauge 3A and the downstream pressure gauge 5A becomes the target differential pressure ΔPr corresponding to the target flow rate desired to flow through the flow path. And the opening degree of the flow rate control valve 7A are controlled.

  However, it is actually difficult to improve the response of the Coriolis flow meter even if the flow control system 100A as shown in Patent Document 1 is applied to a conventional fuel flow measuring device as it is.

  As a result of intensive studies by the inventors of the present invention on this reason, in the conventional fuel flow measuring device, various fluid devices such as filters are also provided downstream of the downstream flow meter provided downstream of the Coriolis flow meter. Therefore, it has been found for the first time that the pressure change measured by the downstream pressure gauge is caused by a response delay with respect to the output change in the internal combustion engine.

JP 2008-89373 A

  The present invention has been made in view of the above-described problems, and improves the responsiveness of the flow meter and can measure a change in fuel consumption and the like in a very short time in an internal combustion engine. It aims at providing a measuring device.

  That is, the fuel flow rate measuring device of the present invention has an outlet port connected to the internal combustion engine, a fuel supply path through which the fuel supplied to the internal combustion engine flows, and the fuel supply path. A flow meter for measuring the flow rate of fuel flowing through the fluid supply mechanism, a fluid control mechanism provided on the upstream side of the flow meter in the fuel supply path, and provided between the fluid control mechanism and the flow meter in the fuel supply path. An upstream pressure gauge, a downstream pressure gauge provided downstream of the flowmeter in the fuel supply passage, an upstream measurement pressure measured by the upstream pressure gauge, and a downstream pressure gauge. A control unit that controls the fluid control mechanism based on a measured differential pressure that is a difference in downstream measured pressure and a target differential pressure, and the downstream pressure gauge is directly connected to the outlet port. Provided in the position And wherein the Rukoto.

  In such a case, since the downstream pressure gauge is provided at a position directly connected to the outlet port, there is no resistance or response delay between the downstream pressure gauge and the internal combustion engine. There is no fluid device to cause. For this reason, the output change in the internal combustion engine can be directly measured by the downstream pressure meter, and the change in the downstream measurement pressure measured by the downstream flow meter is the same as the output change in the internal combustion engine. So that there is almost no response delay.

  For this reason, the control unit quickly follows the change in the output of the internal combustion engine based on the measured differential pressure, which is the differential pressure between the upstream measured pressure and the downstream measured pressure, and the target differential pressure. Can be made.

  As a result, the measured flow rate measured by the flowmeter has almost no response delay with respect to the output change of the internal combustion engine, and has a good response that can satisfy severe requirements in the development of the internal combustion engine. Become.

  The control unit changes the target differential pressure by feedforward control with respect to the output change of the internal combustion engine so that the output change of the internal combustion engine is immediately reflected in the fluid flowing through the fuel supply path, Further, in order to enhance the responsiveness of the measured flow rate in the flow meter, the flow meter is a Coriolis flow meter, the fluid control mechanism is a pump, and the control unit is configured to output the internal combustion engine and the output An output-differential pressure relationship storage unit that stores an output-differential pressure relationship, which is a relationship between the differential pressure before and after the Coriolis flowmeter corresponding to, an actual output or an estimated output of the internal combustion engine, and the output- The target value setting unit that sets the target differential pressure based on the differential pressure relationship, the measured differential pressure, and the difference between the target differential pressure set by the target value setting unit is reduced. Feed supply flow rate Tsu a controller for click control may be one having a.

  Here, the differential pressure before and after the Coriolis flow meter is not only the differential pressure immediately before and after the Coriolis flow meter, but also the pressure at the point where the upstream pressure gauge is provided, the internal combustion engine, It is a concept including at least a differential pressure from a pressure at a point where the downstream pressure gauge is provided at a directly connected position.

  In order to enable the output-differential pressure relationship to accurately model an actual flow control system and further enhance the response improvement effect of the Coriolis flow meter, the output-differential pressure relationship is: An output-fuel flow rate relationship that is a relationship between the output of the internal combustion engine and the flow rate of fuel required in the internal combustion engine according to the output, the flow rate of the fuel, and the flow rate of the fuel are realized. It is sufficient that the relationship be derived based on the fuel flow rate-differential pressure relationship, which is a relationship between the differential pressure before and after the Coriolis flowmeter required for the above.

  Since the downstream measured pressure measured by the downstream pressure gauge in the conventional fuel flow measuring device is delayed with respect to the output change of the internal combustion engine, the entire flow control in the fuel supply path is delayed, and the response of the Coriolis flow meter As another aspect of the fuel flow rate measuring device that can fundamentally solve the problem that the characteristics cannot be improved, an outlet port is connected to the internal combustion engine, a fuel supply path through which the fuel supplied to the internal combustion engine flows, and the fuel A flow meter provided in the supply path for measuring a flow rate of the fuel flowing through the fuel supply path; a fluid control mechanism provided on the upstream side of the flow meter in the fuel supply path; and the fluid in the fuel supply path. The fluid control mechanism based on an upstream pressure gauge provided between the control mechanism and the flow meter, an upstream measurement pressure measured by the upstream pressure gauge, and a target pressure An output that stores an output-upstream pressure relationship that is a relationship between the output of the internal combustion engine and the pressure on the upstream side of the flow meter corresponding to the output. An upstream pressure relationship storage unit, a measured or estimated output of the internal combustion engine, and a target value setting unit that sets a target pressure based on the output-upstream pressure relationship, Can be mentioned.

  If this is the case, only the upstream measurement pressure of the upstream pressure gauge is used without using the downstream measurement pressure of the downstream pressure gauge, which was the cause of the inability to improve the responsiveness of the flow meter in the conventional fuel flow measurement device. Since the fluid control mechanism is controlled by using, the responsiveness of the flowmeter is not impaired. Further, since the control unit sets the target pressure based on the output-upstream pressure relationship, the control of the fuel flow rate is realized by feedforward without waiting for feedback with respect to the output change of the internal combustion engine. Can be increased. Therefore, the flow meter can output a measured flow rate that follows the output change of the internal combustion engine at a sufficient speed.

  Further, even when no pressure gauge is provided on the downstream side of the flow meter, the pressure on the upstream side of the flow meter can be quickly maintained at the target pressure, and the measured flow value measured by the flow meter is the internal combustion engine. As a specific control mode for making it possible to immediately reflect the output change, the flow meter is a Coriolis flow meter, the fluid control mechanism is a pump, and the control unit is What further includes a controller that feedback-controls the supply flow rate of the pump so that a deviation between the upstream measurement pressure and the target pressure set by the target value setting unit is small.

  Thus, according to the fuel flow rate measuring apparatus of the present invention, the downstream pressure gauge is provided at a position directly connected to the internal combustion engine so as not to be delayed with respect to the output change of the internal combustion engine. High-speed flow control in the road can be realized. Therefore, the responsiveness with respect to the change in the output of the internal combustion engine of the flow rate measured by the flow meter can be improved as compared with the prior art.

1 is a schematic diagram showing a fuel flow rate measuring device according to a first embodiment of the present invention. The typical control block diagram which shows the structure of the control part in 1st Embodiment. The typical graph explaining the output-differential pressure relationship in 1st Embodiment. The schematic diagram which shows the fuel flow measuring apparatus which concerns on 2nd Embodiment of this invention. The typical control block diagram which shows the structure of the control part in 2nd Embodiment. The typical graph explaining the output-upstream pressure relationship in 2nd Embodiment. The schematic diagram which shows the flow control system for improving the responsiveness of the conventional Coriolis flowmeter.

  A fuel flow measurement device 100 according to a first embodiment of the present invention will be described with reference to FIGS. 1 to 3.

  The fuel flow measuring device 100 of the first embodiment is for collecting the amount of fuel consumed in an internal combustion engine E such as a gasoline engine or a diesel engine as time series data by simulating the state of an actual vehicle. As shown in FIG. 1, this fuel flow rate measuring device 100 has a fuel supply path 1 for supplying fuel to the internal combustion engine E. The fuel supply path 1 has a pump 2 and an upstream pressure from the upstream side. A total of 3, a Coriolis flow meter 4, and a downstream pressure gauge 5 are provided. In addition, the fuel flow rate measuring device 100 includes a control unit 6 that controls the pump 2 based on the outputs of the upstream pressure gauge 3 and the downstream pressure gauge 5. Further, the fuel flow rate measuring apparatus 100 includes a return flow path 12 that simulates a part that is returned to a fuel tank if the fuel that has not been consumed by the internal combustion engine E as a part of the fuel supply path 1 is an actual vehicle. It is provided in the vicinity of the engine E. The fuel flow rate measuring apparatus 100 may include a calculation unit (not shown) that calculates the fuel consumption amount in the internal combustion engine E based on the mass flow rate value obtained by the Coriolis flow meter 4.

  Each part will be described in detail.

  The fuel supply passage 1 has an outlet port 11 connected to a fuel supply port of the internal combustion engine E, and a fluid resistance other than a pipe wall between the downstream pressure gauge 5 and the internal combustion engine E. Is constructed so that there is no such thing. In addition, on the fuel supply path 1, the return flow path 12, or the flow path connecting the flow paths, a backflow prevention valve 13, in order to simulate the flow rate of fuel returned from the internal combustion engine E to the fuel tank, 15 and a return flow path pump 14 are provided. For example, the backflow prevention valves 13 and 15 prevent the fuel returned from the internal combustion engine E from flowing back upstream from the fuel supply path 1 from the return flow path 12. The return flow path pump 14 forms a flow for simulating a state in which the fuel is returned to the tank.

  The pump 2 is a flow rate control mechanism for controlling the flow rate or pressure of the fuel flowing through the fuel supply path 1. More specifically, the pump 2 controls the supply flow rate of the discharged fuel. For example, the applied voltage and the rotational speed are adjusted by the control unit 6.

  The upstream pressure gauge 3 is provided between the pump 2 and the Coriolis flow meter 4, and measures the pressure on the upstream side of the Coriolis flow meter 4.

  The Coriolis flow meter 4 is a kind of flow meter, and is configured to measure the mass flow rate of the fluid using Coriolis force acting on the fluid. For example, a manifold portion attached to the fuel supply path 1 And two U-shaped narrow tubes that branch from the manifold portion and merge again, an oscillator that causes the two thin tubes to vibrate in a direction perpendicular to the fluid flow direction, and a twist of the narrow tubes The torsion detector to be detected and a flow rate calculation unit for calculating the mass flow rate of the fluid based on the torsion detected by the torsion detector. Note that each part and details of the Coriolis flow meter 4 are not shown. Since this Coriolis flowmeter 4 uses a thin tube, when a fluid with high viscosity such as fuel flows, the pressure loss in the thin tube tends to increase and the responsiveness tends to decrease. For this reason, in order to improve the responsiveness of the Coriolis flow meter 4, it is necessary to change the differential pressure before and after the Coriolis flow meter 4 as quickly as possible.

  The downstream pressure gauge 5 is disposed at a position directly connected to the outlet port 11 in the fuel supply path 1. In other words, a fluid device such as a filter is not provided between the downstream pressure gauge 5 and the outlet port 11, and the downstream pressure does not cause a delay in the output change in the internal combustion engine E. This is reflected in the downstream pressure measured by the total 5. Here, that no delay occurs means that the response is made at a sufficient speed in consideration of the accuracy required in the measurement of the fuel consumption in the internal combustion engine E.

  The controller 6 is a dedicated or general-purpose computer equipped with a CPU, memory, A / D / D / A converter, input / output means, etc., and the program for the fuel flow rate measuring device 100 stored in the memory is executed. The function is realized by the cooperation of the devices. The control unit 6 includes a measured differential pressure ΔP that is a difference between an upstream measured pressure Pu measured by the upstream pressure gauge 3 and a downstream measured pressure Pd measured by the downstream pressure gauge 5, and the Coriolis flow rate. The pump 2 is controlled based on the target differential pressure ΔPr before and after the total 4.

  Hereinafter, a detailed configuration of the control unit 6 will be described with reference to FIG.

  The control unit 6 includes an output-differential pressure relationship storage unit 61, a target value setting unit 62, and a controller 63, and these units cooperate with each other to output the internal combustion engine E. A feedforward unit 6F that changes the target differential pressure ΔPr based on (the work that the internal combustion engine E is performing, or a value that can be converted into work), and the deviation based on the difference between the measured differential pressure ΔP and the target differential pressure ΔPr. A feedback unit 6B that controls the pump 2 is configured.

  The feedforward unit 6F stores the output-differential pressure relationship storage unit 61 that stores an output-differential pressure relationship that is a relationship between an output of the internal combustion engine E and a target differential pressure ΔPr to be set for each output; The target value setting unit 62 sets the target differential pressure ΔPr based on the current estimated output or measurement output of the internal combustion engine E and the output-differential pressure relationship.

  The output-differential pressure relationship is derived based on two relationships, ie, an output-fuel flow rate relationship shown in FIG. 3A and a fuel flow-differential pressure relationship shown in FIG. 3B. The relationship is as shown in (c).

  The output-fuel flow rate relationship shown in FIG. 3A is a relationship between the output of the internal combustion engine E and the flow rate of fuel required in the internal combustion engine E according to the output. More specifically, the output of the internal combustion engine E is a possible value calculated from the rotation speed and torque of the internal combustion engine E. If the output of the internal combustion engine E is known, the required fuel consumption and thus the fuel consumption The flow rate of the fuel flowing through the fuel supply path 1 can also be calculated. Note that the output-fuel flow rate relationship shown in FIG. 3A is an example, and is not limited to the linearity as shown in the graph. For example, the output-fuel flow rate relationship may have a characteristic represented as a non-linear graph.

  Also, the fuel flow rate-differential pressure relationship shown in FIG. 3 (b) is the front and back of the Coriolis flow meter 4 required to realize the flow rate of the fuel and the flow rate of the fuel in the fuel supply path 1. It is the relationship between the differential pressures.

  In addition, about these relationships, a relational expression can be calculated | required by calculation from a design value etc., or a relationship can be identified experimentally.

  3 (a) and 3 (b), the fuel flow rate is a parameter, so the variable representing the fuel flow rate is eliminated from the relational expression showing each relationship. The output-differential pressure relationship as shown in 3 (c) can also be derived.

  In the present embodiment, the output-differential pressure relationship storage unit 61 stores, for example, an approximate expression of a graph as shown in FIG. 3C as the output-differential pressure relationship, but for example, the output of the internal combustion engine E A plurality of data in which the corresponding differential pressures are paired may be stored in a table format.

  The target value setting unit 62 shown in FIG. 2 receives the measured output or the estimated output of the internal combustion engine E, and refers to the output-differential pressure relationship stored in the output-differential pressure relationship storage unit 61. Thus, the received differential pressure corresponding to the output of the internal combustion engine E is set in the controller 63 as the target differential pressure ΔPr. That is, the output of the internal combustion engine E received by the target value setting unit 62 may be, for example, a measured output converted from the currently measured rotational speed or torque of the internal combustion engine E, or the internal combustion engine E The estimated output preliminarily estimated from the operation command data or the like used in the test may be used.

  The feedback unit 6B includes the controller 63 that controls the pump 2 to be controlled based on the measured differential pressure ΔP and the target differential pressure ΔPr, the upstream pressure gauge 3, and the downstream pressure gauge 5. Feedback loop. More specifically, the controller 63 feeds back the measured differential pressure ΔP, and performs, for example, PID calculation or the like on the deviation between the measured differential pressure ΔP and the target differential pressure ΔPr set by the target value setting unit 62. Thus, the operation amount of the pump 2 is calculated. The manipulated variable is, for example, a current applied to the pump 2, a voltage, a command rotational speed, and the like, and changes the supply flow rate from the pump 2. In other words, the controller 63 adjusts the operation amount so that the difference between the measured differential pressure ΔP and the target differential pressure ΔPr becomes small as a result of the supply flow rate from the pump 2 changing.

  According to the fuel flow measuring device 100 of the first embodiment configured as described above, the downstream pressure gauge 5 is provided at a position directly connected to the outlet port 11 of the fuel supply path 1. Between the downstream pressure gauge 5 and the internal combustion engine E, there is no fluid device such as a filter that causes a response delay in the downstream pressure gauge 5. For this reason, the downstream pressure gauge 5 can detect the change in the output in the internal combustion engine E and the change in the fuel consumption associated therewith as the downstream measurement pressure Pd with little delay. Therefore, the flow rate control is delayed due to the downstream measurement pressure Pd as in the prior art, and as a result, the waveform of the measured flow rate measured by the Coriolis flow meter 4 and the output change waveform of the internal combustion engine E are greatly different. Can be prevented.

  Further, since the target differential pressure ΔPr is appropriately changed based on the output of the internal combustion engine E by the feedforward unit 6F, the control delay by the feedback unit 6B itself can be recovered.

  For these reasons, the response of the Coriolis flow meter 4 can be improved to make the change in the measured flow rate of the Coriolis flow meter 4 substantially coincide with the change in the output of the internal combustion engine E or the change in fuel consumption. it can. For this reason, even if it is a change in the fuel consumption that occurs in a very short time, it can be detected as the measured flow rate of the Coriolis flow meter 4.

  A modification of the fuel flow rate measuring apparatus 100 according to the first embodiment will be described below. The pump 2 that is a fluid control mechanism may be a valve, a regulator, or the like. More specifically, a variable needle valve or an electronically controlled regulator may be used as the fluid control mechanism instead of the pump 2. That is, any mechanism may be used as long as the pressure on the upstream side of the Coriolis flow meter 4 can be changed and adjusted to a desired value.

  In the first embodiment, the Coriolis flow meter 4 is used as the flow meter. However, for example, a positive displacement flow meter is used, and the control unit 6 sets the target differential pressure to zero, such as a piston or a rotor of the positive displacement flow meter. It may be configured to control the mover. That is, in the case of this modified example, the moving element of the positive displacement flow meter exhibits a function as a fluid control mechanism instead of the pump 2 in the first embodiment. Even in such a case, since the downstream flowmeter 5 is in a position directly connected to the internal combustion engine E, the output change in the internal combustion engine E is acquired without time delay, and the output change is obeyed. Thus, the differential pressure before and after the positive displacement flow meter can be kept at zero, and the flow rate of the fuel can be measured without causing a measurement error or a time delay.

  Next, a fuel flow rate measuring apparatus 100 according to a second embodiment of the present invention will be described with reference to FIGS. In addition, about each part as described in 2nd Embodiment, suppose that the same code | symbol as each corresponding part of 1st Embodiment is attached | subjected.

  In the fuel flow measuring device 100 of the second embodiment, the downstream pressure gauge 5 is not provided as shown in FIG. 4, and the control unit 6 as shown in FIG. The fuel of the first embodiment is that the pump 2 is not controlled based on the pressure ΔPr, but is controlled based on the upstream measured pressure Pu measured by the upstream pressure gauge 3 and the target pressure Pr. Different from the flow measuring device 100.

  Next, details of the control unit 6 in the second embodiment will be described.

  The control unit 6 according to the second embodiment includes an output-upstream pressure relationship storage unit, a target value setting unit 62, and a controller 63, and the downstream pressure gauge as compared with the first embodiment. Corresponding to the fact that 5 does not exist, the flow control in the fuel supply path 1 can be realized only by the upstream measured pressure Pu measured by the upstream flow meter. That is, the control unit 6 of the second embodiment is configured to control the pump 2 based on the deviation between the upstream measured pressure Pu and the upstream target pressure Pr of the Coriolis flow meter 4. .

  More specifically, the output-upstream pressure relationship storage unit 64 stores the relationship between the output of the internal combustion engine E as shown in FIG. 6 and the upstream pressure of the Coriolis flow meter 4 corresponding to the output. The output-upstream pressure relationship is stored. The output-upstream pressure relationship shown in FIG. 6 assumes, for example, the pressure downstream of the Coriolis flow meter 4 from the output of the internal combustion engine E, and the vertical axis of the graph of FIG. It can be created by applying the assumed downstream pressure and converting it to the upstream pressure. In the second embodiment, the output-upstream pressure relationship storage unit 64 stores an approximate expression indicating the output-upstream pressure relationship. For example, the output of the internal combustion engine E and the required Coriolis flow meter 4 are used. A plurality of data in which two variables of the pressure on the upstream side are paired may be stored in a table format.

  The target value setting unit 62 is configured to receive an actual measurement output or an estimated output of the internal combustion engine E and set the target pressure Pr with reference to the output-upstream pressure relationship as shown in FIG. It is.

  The controller 63 feedback-controls the supply flow rate of the pump 2 based on the deviation between the upstream measured pressure Pu of the upstream pressure gauge 3 and the target pressure Pr set by the target value setting unit 62. It is.

  According to the fuel flow rate measuring apparatus 100 of the second embodiment configured as described above, the pressure on the downstream side of the Coriolis flow meter 4 is not used for the flow rate control in the fuel supply path 1. As described above, since the value measured by the sensor is delayed, it is possible to prevent the measured flow rate of the Coriolis flow meter 4 from being delayed with respect to the output change of the internal combustion engine E as a result.

  Moreover, since the target value setting unit 62 changes the target pressure Pr according to the output of the internal combustion engine E as in the first embodiment, the delay of the flow rate control system is recovered, and the Coriolis flow meter 4 Responsiveness can be further improved.

  Therefore, even the fuel flow measuring device 100 of the second embodiment can achieve substantially the same effect as the first embodiment.

  Next, a modified example of the fuel flow measuring device 100 of the second embodiment will be described. Also in the second embodiment, the pump 2 may be a valve or regulator that is another fluid control mechanism.

  Furthermore, in the fuel flow measuring device 100 of the second embodiment, the upstream pressure gauge 3 is provided only on the upstream side of the Coriolis flow meter 4, and no pressure gauge is provided on the downstream side of the Coriolis flow meter 4. Although the pump 2 is controlled based on the measured pressure and the target pressure, this relationship may be reversed.

  More specifically, the upstream pressure gauge 3 provided on the upstream side of the Coriolis flow meter 4 is omitted, and only the downstream pressure gauge 5 is provided on the downstream side of the Coriolis flow meter 4. You may comprise so that the said pump 2 which is a fluid control mechanism may be controlled based on the downstream measurement pressure and target pressure which are measured with the downstream pressure gauge 5. FIG. If this is the case, the downstream pressure gauge 5 acquires the output change of the internal combustion engine E without time delay, and quickly realizes the pressure that should be achieved before and after the Coriolis flow meter 4, It becomes possible to measure the flow rate of fuel that accurately reflects the fuel consumption.

  Further, as described above, when only the downstream pressure sensor 5 is provided at a position directly connected to the internal combustion engine E, the flow rate of the fuel in the fuel supply path 1 is controlled based only on the measured value of the downstream pressure sensor 5. Instead of the Coriolis flow meter 4, a positive displacement flow meter may be used. In this modification, the target pressure or the target differential pressure set by the target value setting unit 62 is set so that the pressure before and after the positive displacement flow meter becomes zero.

  Other embodiments will be described.

  The installation location of the downstream pressure gauge in the first embodiment is not limited to the location shown in FIG. 1, and may be provided, for example, on the return channel. The fact that the outlet port and the downstream pressure gauge are directly connected means, for example, that no other fluid device is sandwiched between them, and the delay caused by the fluid resistance due to the inner surface of the pipe does not become a problem with respect to the separation distance. Any degree is acceptable. That is, a predetermined distance may exist between the outlet port and the downstream pressure gauge as long as the delay is smaller than the allowable time delay in the fuel flow measurement. In the outlet port and the downstream pressure gauge, the outlet port and the downstream pressure gauge are adjacent to each other or separated from each other by a predetermined distance, and there is no fluid device such as another filter between them. May be arranged as follows.

  The control unit of each of the embodiments has received the output value itself of the internal combustion engine. For example, the rotation speed or torque itself, or the accelerator opening degree achieved by the internal combustion engine is used as the output of the internal combustion engine. It may be configured to accept and set a target differential pressure or a target pressure. More specifically, from the viewpoint of measuring the fuel flow rate, when the internal combustion engine is a gasoline engine, it is preferable to set a target differential pressure or a target pressure from the rotational speed or torque. On the other hand, when the internal combustion engine is a diesel engine, it is preferable to set a target differential pressure or a target pressure based on the accelerator opening. Further, the control unit may be configured to perform flow rate control in the fuel supply path based on a target differential pressure or target pressure fixed in advance.

  That is, the present invention improves the delay of the Coriolis flow meter with respect to the output change of the internal combustion engine only by providing the downstream pressure gauge directly below the internal combustion engine or by not using the downstream pressure gauge for flow control. The effect to do.

  In addition, various modifications and combinations of the embodiments may be made without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 100 ... Fuel flow measuring device 1 ... Fuel supply path 11 ... Outlet port 12 ... Return flow path 2 ... Pump 3 ... Upstream pressure gauge 4 ... Coriolis flow meter 5・ ・ Downstream pressure gauge 6 ・ ・ ・ Control unit 61 ・ ・ ・ Output-differential pressure relationship storage unit 62 ・ ・ ・ Target value setting unit 63 ・ ・ ・ Controller 64 ・ ・ ・ Output-upstream pressure relationship storage unit E ..Internal combustion engines

Claims (3)

A fuel supply path through which an outlet port is connected to the internal combustion engine, and fuel supplied to the internal combustion engine flows;
A flow meter provided in the fuel supply path for measuring the flow rate of fuel flowing through the fuel supply path;
A fluid control mechanism provided upstream of the flow meter in the fuel supply path;
An upstream pressure gauge provided between the fluid control mechanism and the flow meter in the fuel supply path;
A downstream pressure gauge provided downstream of the flow meter in the fuel supply path;
The fluid control mechanism is controlled based on a measured differential pressure that is a difference between an upstream measured pressure measured by the upstream pressure gauge and a downstream measured pressure measured by the downstream pressure gauge, and a target differential pressure. A control unit,
The downstream pressure gauge is provided at a position directly connected to the outlet port;
The control unit is
An output-differential pressure relationship storage unit that stores an output-differential pressure relationship that is a relationship between the output of the internal combustion engine and the differential pressure before and after the flowmeter corresponding to the output;
A target value setting unit that sets the target differential pressure based on the measured output or estimated output of the internal combustion engine and the output-differential pressure relationship;
A controller that feedback-controls a supply flow rate of the fluid control mechanism so that a deviation between the measured differential pressure and the target differential pressure set by the target value setting unit is small. Fuel flow measurement device. The flow meter is a Coriolis flow meter;
  The fuel flow rate measuring device according to claim 1, wherein the fluid control mechanism is a pump. The output-differential pressure relationship is
An output-fuel flow rate relationship that is a relationship between the output of the internal combustion engine and the flow rate of fuel required in the internal combustion engine in response to the output;
A fuel flow rate-differential pressure relationship, which is a relationship between the fuel flow rate and the differential pressure before and after the Coriolis flow meter required to realize the fuel flow rate;
The fuel flow rate measuring device according to claim 2, wherein the relationship is derived based on