GB2360593A - Sensor for detecting knocking in an internal combustion engine - Google Patents
Sensor for detecting knocking in an internal combustion engine Download PDFInfo
- Publication number
- GB2360593A GB2360593A GB0029550A GB0029550A GB2360593A GB 2360593 A GB2360593 A GB 2360593A GB 0029550 A GB0029550 A GB 0029550A GB 0029550 A GB0029550 A GB 0029550A GB 2360593 A GB2360593 A GB 2360593A
- Authority
- GB
- United Kingdom
- Prior art keywords
- sensor
- internal combustion
- combustion engine
- detecting knocking
- knocking
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
- G01P15/00—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration
- G01P15/02—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses
- G01P15/08—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses with conversion into electric or magnetic values
- G01P15/125—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses with conversion into electric or magnetic values by capacitive pick-up
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L23/00—Devices or apparatus for measuring or indicating or recording rapid changes, such as oscillations, in the pressure of steam, gas, or liquid; Indicators for determining work or energy of steam, internal-combustion, or other fluid-pressure engines from the condition of the working fluid
- G01L23/22—Devices or apparatus for measuring or indicating or recording rapid changes, such as oscillations, in the pressure of steam, gas, or liquid; Indicators for determining work or energy of steam, internal-combustion, or other fluid-pressure engines from the condition of the working fluid for detecting or indicating knocks in internal-combustion engines; Units comprising pressure-sensitive members combined with ignitors for firing internal-combustion engines
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L23/00—Devices or apparatus for measuring or indicating or recording rapid changes, such as oscillations, in the pressure of steam, gas, or liquid; Indicators for determining work or energy of steam, internal-combustion, or other fluid-pressure engines from the condition of the working fluid
- G01L23/22—Devices or apparatus for measuring or indicating or recording rapid changes, such as oscillations, in the pressure of steam, gas, or liquid; Indicators for determining work or energy of steam, internal-combustion, or other fluid-pressure engines from the condition of the working fluid for detecting or indicating knocks in internal-combustion engines; Units comprising pressure-sensitive members combined with ignitors for firing internal-combustion engines
- G01L23/221—Devices or apparatus for measuring or indicating or recording rapid changes, such as oscillations, in the pressure of steam, gas, or liquid; Indicators for determining work or energy of steam, internal-combustion, or other fluid-pressure engines from the condition of the working fluid for detecting or indicating knocks in internal-combustion engines; Units comprising pressure-sensitive members combined with ignitors for firing internal-combustion engines for detecting or indicating knocks in internal combustion engines
- G01L23/225—Devices or apparatus for measuring or indicating or recording rapid changes, such as oscillations, in the pressure of steam, gas, or liquid; Indicators for determining work or energy of steam, internal-combustion, or other fluid-pressure engines from the condition of the working fluid for detecting or indicating knocks in internal-combustion engines; Units comprising pressure-sensitive members combined with ignitors for firing internal-combustion engines for detecting or indicating knocks in internal combustion engines circuit arrangements therefor
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
- G01P15/00—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration
- G01P15/02—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses
- G01P15/08—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses with conversion into electric or magnetic values
- G01P2015/0805—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses with conversion into electric or magnetic values being provided with a particular type of spring-mass-system for defining the displacement of a seismic mass due to an external acceleration
- G01P2015/0808—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses with conversion into electric or magnetic values being provided with a particular type of spring-mass-system for defining the displacement of a seismic mass due to an external acceleration for defining in-plane movement of the mass, i.e. movement of the mass in the plane of the substrate
- G01P2015/0811—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses with conversion into electric or magnetic values being provided with a particular type of spring-mass-system for defining the displacement of a seismic mass due to an external acceleration for defining in-plane movement of the mass, i.e. movement of the mass in the plane of the substrate for one single degree of freedom of movement of the mass
- G01P2015/0814—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses with conversion into electric or magnetic values being provided with a particular type of spring-mass-system for defining the displacement of a seismic mass due to an external acceleration for defining in-plane movement of the mass, i.e. movement of the mass in the plane of the substrate for one single degree of freedom of movement of the mass for translational movement of the mass, e.g. shuttle type
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Combustion & Propulsion (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Combined Controls Of Internal Combustion Engines (AREA)
- Measuring Fluid Pressure (AREA)
- Pressure Sensors (AREA)
- Testing Of Engines (AREA)
Abstract
A sensor for detecting the knocking of an internal combustion engine which is designed as a surface-micromechanics sensor, with two capacitances changing in opposing senses in the event of an acceleration. With the aid of an evaluating circuit these changes in capacitance are converted into a voltage depending on the capacitance, which is consequently also a measure of accelerations caused by knocking. Knocking arising is detected by evaluating this voltage.
Description
2360593 Sensor f or detecting knocking in an internal combustion The
invention takes as its starting-point a sensor for detecting knocking in an internal combustion engine, according to the type specified in the main claim.
State of the Art The undesirable knocking of an internal combustion engine which occurs under certain conditions is ascertained conventionally with the aid of sensors which register vibrations on parts of the engine. Pressure gauges, force transducers or acceleration pickups are used as sensors in this connection. Most of the time, the signal emitted by the knocking sensor is burdened with a background noise or background signal which arises as a result of normal engine operation. Separating the signal caused by the knocking from the signal caused by the background noise is often problematic, and elaborate measures for signal processing are conventionally required which enable a reliable separation of knocking signal and background signal.
A device for capturing the vibrations arising in the event of knocking of an internal combustion engine, with which the aforementioned problems are addressed, is known from DE?PS 29 42 250, for example. Pressure sensors, force sensors or acceleration sensors are employed in this case by way of sensors which register the vibrations.
With flirther knocking sensors currently in use, which capture the solidbome sound vibrations with the aid of a piezoceramic element and a seismic mass and which are known from DE 40 00 903 Cl for example, it is already possible for the solid-borne sound vibrations to be securely detected and captured. However, the object underlying the invention consists in demonstrating a still more reliable sensor with improved signal evaluation, with which the knocking of an internal combustion engine can be ascertained.
2 Advantages of the Invention In comparison with traditional sensors for detecting knocking, the sensor according to the invention for detecting knocking in an internal combustion engine has the advantage that it is more cost-effective, that it exhibits a smaller spread of sensitivity, that only very slight ageing effects arise, that no resonant rise in the frequency response occurs, and only a very slight temperature drift is present. In advantageous manner this results in a better performance in comparison with traditional knocking sensors. Moreover, the small physical size of the sensor is an advantage, and moisture which may possibly appear in the cable between the sensor and the control unit and also in the plug is less critical than in the case of the very highly resistive piezocerarnic elements. Traditional standard cables for connecting the sensor to the evaluating electronics can be employed in advantageous manner.
These advantages are achieved by a micromechanical sensor element being employed for the acceleration measurement. Such a micromechanical sensor element, which is also called a surface-micromechanics sensor element, undergoes a capacitive change in the event of an acceleration, which can be measured with the aid of an evaluating circuit and can be used for the purpose of detecting knocking.
Further advantages of the invention are achieved by virtue of the measures specified in the subordinate claims. Particularly advantageous in this connection is the signal evaluation via a special ASIC which advantageously comprises a capacitance/voltage transformer, an amplifier with integrated highpass filter and an interface for the signal transmission. Signal transmission can be effected in advantageous manner via a two-wire interface in which the voltage supply and the electrical, analogue or digital signal are transmitted jointly via two lines. Alternatively, signal transmission may also be effected in advantageous manner via a conventional three-wire interface, with one line in each case for the voltage supply, the signal and earth.
3 Drawing An example of an embodiment of the invention is represented in the drawing and will be elucidated in greater detail in the following description. Specifically, Figure 1 shows the structure of a surfacemicromechanics sensor, Figure 2 shows an associated circuit diagram, and in Figure 3 an example of an embodiment of an evaluating circuit for a surface-micromechanics sensor is shown.
Description
The sensor S represented in Figure 1, which is already known from DE 40 00 903 C 1, exhibits a symmetrical structure with fixed fingers (electrodes) and movable fingers (tongues) and consists of a support 10 made of monocrystalline material (silicon wafer), on which a structured conducting layer is applied. The upper layer which is applied onto the support consequently comprises several conducting comb-shaped areas or tongues 11, 12, 13 which are, however, electrically isolated from one another. A tongue base 14 with two tongues 15, 16 which are capable of oscillating in the plane of the support and which are perpendicular to the tongue base 14 is arranged parallel to a tongue base 17 which is similarly structured, likewise with two tongues 18, 19 which are capable of oscillating in the plane of the support, the arrangement being such that the tongues 15, 16 and 18, 19 are located opposite one another. Located in between, parallel to the two tongue bases 14 and 17, is the electrode base 12, from which four immovable electrodes 20, 21, 22, 23 emanate. The number of tongues and electrodes can be varied arbitrarily.
The two tongues 15 and 16 form, together with the two associated electrodes 20 and 2 1, two capacitors connected in parallel, which are located opposite the two capacitors, likewise connected in parallel, formed by the two tongues 18 and 19 in conjunction with the two electrodes 22 and 23. Since the arrangement of the tongues is inverse with respect to the associated electrodes, an acceleration deflecting the 4 tongues results in inverse changes in spacing between tongues and electrodes. For the associated capacitors this means that an acceleration arising causes inverse changes in the capacitances. With a view to ascertaining the acceleration, the change in capacitance is evaluated (differential evaluation of capacitance).
The sensor S described above is connected via three connectors 24, 25, 26 to an evaluating circuit 27 which may be constructed as an autonomous circuit or may be an integral part of the control unit. In the evaluating circuit 27 the changes in capacitance are converted into acceleration values, and these acceleration values are then subjected to further processing with a view to detecting knocking.
The capacitances C 1 and C2 to be evaluated and which change in opposing senses in the event of acceleration are represented in Figure 2 as an electrical circuit diagram. Moreover, the associated sensor connectors 24, 25 and 26 and the actual evaluating circuit 27 are indicated.
Represented in Figure 3 is an example of an embodiment of the entire evaluating circuit 27 with which the capacitances C I and C2 of the sensor arrangement are determined in the form according to the invention. The evaluating circuit 27 is, for example, integrated on a special ASIC.
In detail, this ASIC contains by way of essential components a CN transformer (capacitance/voltage transformer), an amplifier with an integrated highpass filter, and an interface for the signal transmission. Signal transmission is effected here via a two-wire interface in which the voltage supply and the electrical, analogue or digital signal are transmitted jointly via two lines.
In the embodiment example according to Figure 3 the W transformer (capacitance/voltage transformer) is designated by 28; it comprises an operational amplifier 29 with high slew-rate and a sample-and-hold circuit 30 with an operational amplifier 31 as well as an earthed capacitor 32. The switching operations necessary for the capacitance/voltage conversion are triggered via switching means U l, U2a, U2b and U3. The switching means U l, U2a, U2b and U3 are selected by means of an oscillator 33. In this connection the signals SUI, SU2 and SU3 are supplied to the switching means in the time sequence represented. With switching means closed, the voltage V2 is applied as reference voltage to the connector 24 of the capacitor C2. With switch U2b open, the capacitor Cl lies via the connectors 25, 26 between the inverting input and the output of the amplifier 29, and with switch U2b closed the connectors 25 and 26 are directly connected to one another.
The amplifier 34 with integrated highpass filter amplifies the output signal of the sample-and-hold circuit 30. The amplifier is composed of an operational amplifier 35, the resistors 36, 37 and 38 and also the lowpass filter 39 which, for example, is realised using switched- capacitor technology. The select signals SUI and SU2 are supplied to the lowpass filter 39.
The further circuitry comprises a capacitor 40, an active Zener diode 41 and also a voltage supply 43 which is composed of the constant-current source 44, the transistors 45 and 46 as well as the resistors 47 and 48 and is connected to the supply voltage VDDint.
The active Zener diode retains the potential at the node 49. This ensures that a stable internal supply of the evaluating ASIC is provided.
Signal transmission is effected by modulating the output signal of the operational amplifier 35 upon the external supply line via the two resistors 48 and 47. The magnitude of the amplitude of the signal can be adjusted via the resistance ratio R48/R47 of the two resistors 48 and 47.
As an alternative to the embodiment according to Figure 3, the signal transmission 6 from the sensor to the control unit may also be effected via a conventional three-wire interface (VDD, signal, earth).
With the voltage generated in the circuit according to Figure 3, which is a measure of the accelerations induced by knocking of the internal combustion engine and registered by the sensor, knocking can be detected by the control unit of the internal combustion engine, and suitable countermeasures can be taken.
7
Claims (1)
- Claims1. A sensor for detecting knocking in an internal combustion engine, with a sensor element which emits an output signal depending on accelerations arising, which is evaluated with a view to detecting the acceleration, wherein the sensor element is a surface-micromechanics sensor element, with two capacitances changing in opposing senses in the event of an acceleration, characterised in that the change in capacitance is evaluated with a view to detecting knocking in the internal combustion engine.2. Sensor for detecting knocking in an internal combustion engine according to Claim 1, characterised in that the sensor element exhibits a specifiable number of tongues which, together with tongues located opposite as well as associated stationary electrodes, form capacitances changing in opposing senses.3. Sensor for detecting knocking in an internal combustion engine according to Claim 1 or 2, characterised in that the output signal of the sensor element is supplied to an evaluating circuit which comprises at least.a capacitance/ voltage transformer, an amplifier with, where appropriate, integrated highpass filter, and an interface for the signal transmission.4. Sensor for detecting knocking in an internal combustion engine according to one of the preceding claims, characterised in that signal transmission is effected via a two-wire interface wherein the voltage supply and the electrical, analogue or digital signal are transmitted jointly via two lines or in that signal transmission is effected via a three-wire interface for supply voltage, signal and earth.8 5. Sensor for detecting knocking in an internal combustion engine according to one of Claims 3 or 4, characterised in that the evaluating circuit additionally exhibits at least one input capacitor and an active Zener diode for the purpose of voltage stabilisation.6. Sensor for detecting knocking in an internal combustion engine according to one of Claims 3, 4 or 5, characterised in that at least one filter is constructed using switched-capacitor technology.7. Sensor for detecting knocking in an internal combustion engine according to one of the preceding claims, characterised in that the sensor is connected to the control unit of the internal combustion engine via the evaluating circuit.8. A sensor for detecting knocking in an internal combustion engine substantially as herein described with reference to the accompanying drawings.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE1999161299 DE19961299B4 (en) | 1999-12-18 | 1999-12-18 | Sensor for detecting knocking in an internal combustion engine |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB0029550D0 GB0029550D0 (en) | 2001-01-17 |
| GB2360593A true GB2360593A (en) | 2001-09-26 |
Family
ID=7933313
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB0029550A Withdrawn GB2360593A (en) | 1999-12-18 | 2000-12-04 | Sensor for detecting knocking in an internal combustion engine |
Country Status (4)
| Country | Link |
|---|---|
| JP (1) | JP2001272414A (en) |
| DE (1) | DE19961299B4 (en) |
| FR (1) | FR2802637B1 (en) |
| GB (1) | GB2360593A (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE10294625D2 (en) * | 2001-10-05 | 2004-07-22 | Continental Teves Ag & Co Ohg | Accelerometers for motor vehicles |
| DE10253932B4 (en) | 2002-11-19 | 2013-04-04 | Continental Automotive Gmbh | Method for determining the injection quantity of an internal combustion engine |
| JP5496515B2 (en) * | 2009-01-22 | 2014-05-21 | 曙ブレーキ工業株式会社 | Acceleration sensor circuit and three-axis acceleration sensor circuit |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2101336A (en) * | 1981-07-02 | 1983-01-12 | Centre Electron Horloger | Capacitive accelerometers |
| US4653326A (en) * | 1984-01-12 | 1987-03-31 | Commissariat A L'energie Atomique | Directional accelerometer and its microlithographic fabrication process |
| US4711128A (en) * | 1985-04-16 | 1987-12-08 | Societe Francaise D'equipements Pour La Aerienne (S.F.E.N.A.) | Micromachined accelerometer with electrostatic return |
| GB2240178A (en) * | 1990-01-15 | 1991-07-24 | Bosch Gmbh Robert | Acceleration sensor with etched vibratable tongue |
| EP0539071A2 (en) * | 1991-10-23 | 1993-04-28 | Lucas Industries Public Limited Company | Knock processing circuit |
| GB2281126A (en) * | 1993-07-28 | 1995-02-22 | Fuji Electric Co Ltd | Semiconductor capacitive acceleration sensor |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2942250A1 (en) * | 1979-10-19 | 1981-05-07 | Robert Bosch Gmbh, 7000 Stuttgart | DEVICE FOR DETECTING THE VIBRATIONS WHEN TAPPING AN INTERNAL COMBUSTION ENGINE |
| JPS6123874A (en) * | 1984-07-11 | 1986-02-01 | Fuji Heavy Ind Ltd | Ignition-timing controller for internal-combustion engine |
| JPS61105861A (en) * | 1985-06-05 | 1986-05-23 | Nissan Motor Co Ltd | Semiconductor device with beam structure |
| JPS6264921A (en) * | 1985-09-17 | 1987-03-24 | Mazda Motor Corp | Apparatus for detecting knocking of engine |
| JP3804242B2 (en) * | 1998-01-13 | 2006-08-02 | 株式会社デンソー | Electrostatic servo physical quantity detector |
| CN1157594C (en) * | 1999-07-09 | 2004-07-14 | Nec东金株式会社 | Capacitive strain sensor and method for using same |
-
1999
- 1999-12-18 DE DE1999161299 patent/DE19961299B4/en not_active Expired - Fee Related
-
2000
- 2000-12-04 GB GB0029550A patent/GB2360593A/en not_active Withdrawn
- 2000-12-15 FR FR0016382A patent/FR2802637B1/en not_active Expired - Fee Related
- 2000-12-18 JP JP2000384316A patent/JP2001272414A/en active Pending
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2101336A (en) * | 1981-07-02 | 1983-01-12 | Centre Electron Horloger | Capacitive accelerometers |
| US4653326A (en) * | 1984-01-12 | 1987-03-31 | Commissariat A L'energie Atomique | Directional accelerometer and its microlithographic fabrication process |
| US4711128A (en) * | 1985-04-16 | 1987-12-08 | Societe Francaise D'equipements Pour La Aerienne (S.F.E.N.A.) | Micromachined accelerometer with electrostatic return |
| GB2240178A (en) * | 1990-01-15 | 1991-07-24 | Bosch Gmbh Robert | Acceleration sensor with etched vibratable tongue |
| EP0539071A2 (en) * | 1991-10-23 | 1993-04-28 | Lucas Industries Public Limited Company | Knock processing circuit |
| GB2281126A (en) * | 1993-07-28 | 1995-02-22 | Fuji Electric Co Ltd | Semiconductor capacitive acceleration sensor |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2001272414A (en) | 2001-10-05 |
| GB0029550D0 (en) | 2001-01-17 |
| DE19961299A1 (en) | 2001-06-21 |
| FR2802637A1 (en) | 2001-06-22 |
| FR2802637B1 (en) | 2003-11-07 |
| DE19961299B4 (en) | 2009-04-30 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |