Fluid Measurement Device

• US 20150377676A1
• Filed: 06/27/2012
• Published: 12/31/2015
• Est. Priority Date: 06/27/2012
• Status: Active Grant

• Current Assignee: Hitachi Astemo Ltd. (Hitachi, Ltd.)
• Original Assignee: Hitachi Automotive Systems Limited (Hitachi, Ltd.)
• Inventors: ASANO, Satoshi, MATSUMOTO, Masahiro, NAKANO, Hiroshi, HANZAWA, Keiji
• Granted Patent: US 9,574,925 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G01F 1/68 by using thermal effects
• CPC Class Codes: G01F 1/684 Structural arrangements; Mounting of elements, e.g. in relation to fluid flow
• CPC Class Codes: G01F 1/696 Circuits therefor, e.g. constant-current flow meters
• CPC Class Codes: G01F 15/02 Compensating or correcting for variations in pressure, density or temperature
• CPC Class Codes: G01F 5/00 Measuring a proportion of the volume flow

Abstract

There is provided a fluid measurement device that is high in measurement precision. The fluid measurement device has a circuit unit into which a first signal S1 output from a first detection element and a second signal S2 output from a second detection element are to he input, wherein the circuit unit includes signal processing means that outputs a third signal S3 according to the first signal and the second signal, state deciding means that decides a state of the first signal, and control means that controls an amount of change that a change of the first signal imparts to the third signal in accordance with a result of decision by the state deciding means.

Claims

1. A fluid measurement device, having a circuit unit into which a first signal output from a first detection element and a second signal output from a second detection element are input,

wherein the circuit unit includes:

signal processing means that outputs a third signal in accordance with the first signal and the second signal;

state deciding means that decides a state of the first signal; and

control means that controls an amount of change that a change of the first signal imparts to the third signal in accordance with a result of decision by the state deciding means.

2. The fluid measurement device according to claim 1,

wherein the control means:

controls the amount of change to be imparted to the third signal such that a correlation coefficient of an amount of change of the first signal with an amount of change in difference between the second signal and the third signal enters into such a relationship as to change constantly or continuously, within a range indicating that the first signal is in a normal state in the result of decision by the state deciding means; and

controls the amount of change to be imparted to the third signal such that the correlation coefficient of the amount of change of the first signal with the amount of change in difference between the second signal and the third signal changes discontinuously, out of the range indicating that the first signal is in the normal state in the result of decision by the state deciding means.

3. The fluid measurement device according to claim 1,

wherein the control means is provided with means that sets an upper limit to the amount of change that the change of the first signal imparts to the third signal.

4. The fluid measurement device according to claim 1,

wherein the control means is provided with means that sets a lower limit to the amount of change that the change of the first signal imparts to the third signal.

5. The fluid measurement device according to claim 1,

wherein the control means is provided with means that sets an upper limit and a lower limit to the amount of change that the change of the first signal imparts to the third signal.

6. The fluid measurement device according to claim 1,

wherein the control means is provided with invalidation means that reduces to zero the amount of change that the change of the first signal imparts to the third signal.

7. The fluid measurement device according to claim 6,

wherein the invalidation means is provided with means that sets the second signal as the third signal.

8. The fluid measurement device according to claim 6,

wherein the invalidation means is provided with means that sets a predetermined value as the third signal.

9. The fluid measurement device according to claim 1,

wherein the state deciding means is provided with means that decides to be abnormal in a case where the first signal is larger than a predetermined value.

10. The fluid measurement device according to claim 1,

wherein the state deciding means is provided with means that decides to be abnormal in a case where the first signal is smaller than a predetermined value.

11. The fluid measurement device according to claim 1,

wherein the state deciding means is provided with means that decides to be abnormal in a case where the first signal has deviated from a predetermined range.

12. The fluid measurement device according to claim 1, comprising notification means that notifies the outside of the result of decision by the state deciding means.

13. The fluid measurement device according to claim 12,

wherein the notification means is provided with predetermined communication means.

14. The fluid measurement device according to claim 1,

wherein the first detection element is an element that detects a temperature of a fluid, and

the second detection element is an element that detects a flow rate of the fluid.