# US 10,502,101 B2 · Variable valve system

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- Number: US 10,502,101 B2
- Document ID: US10502101B2
- Status: Granted
- Kind: B2
- Application number: 15/559,575
- Filed: 2016-03-11
- Published: 2018-02-15
- Granted: 2019-12-10
- Earliest claimed: 2015-03-27
- Assignees: Denso Corporation
- Applicants: Denso Corporation
- Inventors: Haruyuki Urushihata
- Web page: https://patentgrep.com/patent/US10502101B2

## CPC

- F01L 13/00: Modifications of valve-gear to facilitate reversing, braking, starting, changing compression ratio, or other specific operations
- F01L 1/352: using bevel or epicyclic gear
- F02D 13/0219: {by shifting the phase, i.e. the opening periods of the valves are constant}
- F02D 41/009: {using means for generating position or synchronisation signals}
- G01M 15/06: by monitoring positions of pistons or cranks
- F01L 1/053: overhead type
- F01L 2013/111: {Camshafts position or phase}
- F01L 2013/113: {crankshafts position}
- F01L 2250/02: the camshaft being driven by chains
- F01L 2800/14: Determining a position, e.g. phase or lift
- F01L 2820/032: Electric motors
- F01L 2820/041: Camshafts position or phase sensors
- F01L 2820/042: Crankshafts position
- F02D 41/2474: {Characteristics of sensors}
- F02D 2041/001: {for engines with variable valve actuation}
- F02D 2041/281: {between sensors and control unit}
- F02D 2200/101: Engine speed
- Y02T 10/12: Improving ICE efficiencies
- F01L: CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
- 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)
- G01M: TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION

## Abstract

A variable valve system including a crank angle sensor that measures a rotation angle of a crankshaft, a cam angle sensor that measures a rotation angle of a camshaft coupled to the crankshaft and which opens and closes valves, and a controller that controls the internal combustion engine. At least one of the crank angle sensor or the cam angle sensor is configured as an absolute angle sensor that measures an absolute rotation angle and outputs a voltage signal corresponding to this rotation angle. The controller is configured to perform a correction operation that corrects a rotation angle value calculated based on the voltage signal.

## Claims

### Claim 1

A variable valve system for varying opening and closing timings of valves in an internal combustion engine, comprising:
a crank angle measurement unit that measures a rotation angle of a crankshaft in the internal combustion engine;
a cam angle measurement unit that measures a rotation angle of a camshaft coupled to the crankshaft, the camshaft configured to open and close the valves; and
a controller that controls the internal combustion engine, wherein
at least one of the crank angle measurement unit or the cam angle measurement unit is configured as an absolute angle sensor that measures an absolute rotation angle and outputs a voltage signal corresponding to the absolute rotation angle,
the controller is configured to perform a correction operation that corrects a rotation angle value calculated based on the voltage signal,
the variable valve system further comprises a rotating electric machine for varying a camshaft phase, the camshaft phase being a relative rotation angle of the camshaft with respect to the crankshaft,
the rotating electric machine includes an output shaft and is configured to:
regulate a rotation speed of the output shaft to match the camshaft phase to a target value, and
output a pulse shaped rotation angle signal each time a rotation angle of the output shaft changes by a predetermined amount, and
the controller performs the correction operation further based on the pulse shaped rotation angle signal.

### Claim 2 (depends on 1)

The variable valve system of claim 1, wherein
the controller performs the correction operation further based on a source voltage input from the absolute angle sensor.

### Claim 3 (depends on 1)

The variable valve system of claim 1, wherein
the controller performs the correction operation further based on a rotation speed of the internal combustion engine.

### Claim 4 (depends on 1)

The variable valve system of claim 1, wherein
the controller performs the correction operation further based on a sensor temperature or a sensor mounting portion temperature of the absolute angle sensor.

### Claim 5 (depends on 1)

The variable valve system of claim 1, wherein
the controller is configured to determine whether a malfunction has occurred in the absolute angle sensor based on the pulse shaped rotation angle signal.