# US 9,752,971 B2 · Viscosity measuring apparatus

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- Number: US 9,752,971 B2
- Document ID: US9752971B2
- Status: Granted
- Kind: B2
- Application number: 14/408,026
- Filed: 2012-06-18
- Published: 2015-04-16
- Granted: 2017-09-05
- Earliest claimed: 2012-06-18
- Assignees: Toyota Jidosha Kabushiki Kaisha
- Applicants: Sho Tomita; Rentaro Kuroki
- Inventors: Sho Tomita; Rentaro Kuroki
- Web page: https://patentgrep.com/patent/US9752971B2

## CPC

- G01N 11/00: Investigating flow properties of materials, e.g. viscosity, plasticity; Analysing materials by determining flow properties
- F01P 11/18: concerning coolant pressure, coolant flow, or liquid-coolant level
- G01M 15/08: by monitoring pressure in cylinders
- F01P 2003/001: {Cooling liquid}
- F02D 35/023: {by determining the cylinder pressure}
- F02D 2200/0614: Actual fuel mass or fuel injection amount
- F02D 2200/1012: Engine speed gradient
- G01N 2011/006: {Determining flow properties indirectly by measuring other parameters of the system}
- G01N 2011/0093: {thermal properties}
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)
- F01P: COOLING OF MACHINES OR ENGINES IN GENERAL; COOLING OF INTERNAL-COMBUSTION ENGINES (arrangements in connection with cooling of propulsion units in vehicles B60K11/00; heat-transfer, heat-exchange or heat-storage materials C09K5/00; {cooling of gas-turbine engines F02C7/12}; heat exchange in general, radiators F28)
- G01M: TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- F02D: CONTROLLING COMBUSTION ENGINES (vehicle fittings, acting on a single sub-unit only, for automatically controlling vehicle speed B60K31/00; conjoint control of vehicle sub-units of different type or different function, road vehicle drive control systems for purposes other than the control of a single sub-unit B60W)

## Abstract

A viscosity measuring apparatus is mounted on a vehicle provided with an engine, a cylinder pressure sensor configured to detect cylinder pressure which is inner pressure of a cylinder of the engine, a fuel injection valve configured to supply fuel to the engine, and a temperature sensor configured to detect temperature of a coolant of the engine. The viscosity measuring apparatus is provided with: an estimating device configured to calculate a cooling loss from a heating value of the cylinder based on the cylinder pressure detected by the cylinder pressure sensor and an input heating value of the cylinder, and to estimate viscosity of the coolant on the basis of the calculated cooling loss.

## Claims

### Claim 1

A viscosity measuring apparatus mounted on a vehicle comprising an engine, a cylinder pressure sensor configured to detect cylinder pressure which is inner pressure of a cylinder of the engine, a fuel injection valve configured to supply fuel to the engine, and a temperature sensor configured to detect temperature of a coolant of the engine, said viscosity measuring apparatus comprising:
an estimating device configured to calculate a cooling loss from a heating value of the cylinder based on the cylinder pressure detected by the cylinder pressure sensor and an input heating value of the cylinder, and to estimate viscosity of the coolant on the basis of a relation between the viscosity of the coolant and a cooling loss, which is led from an operation condition of the engine and the temperature of the coolant detected by said temperature sensor, and the calculated cooling loss.

### Claim 2 (depends on 1)

The viscosity measuring apparatus according to claim 1, further comprising a determining device configured to determine that the viscosity is abnormal if the estimated viscosity deviates from a designed value of the coolant by a predetermined value or more.

### Claim 3 (depends on 2)

The viscosity measuring apparatus according to claim 2, wherein the estimation of the viscosity by said estimating device and the determination of the abnormal viscosity by said determining device are performed if each of a time differential value of number of revolutions of the engine, a time differential value of an injection quantity of the fuel injection valve, and a time differential value of the temperature detected by the temperature sensor is less than or equal to respective one of predetermined values.