Measuring and testing – Simulating operating condition – Marine
Patent
1995-11-10
1997-09-16
Dombroske, George M.
Measuring and testing
Simulating operating condition
Marine
731181, G01F 1502, G01F 100, G01D 302, F02D 4118
Patent
active
056683138
DESCRIPTION:
BRIEF SUMMARY
PRIOR ART
The invention relates to a method for correcting the pulsation error in the output signal of an air mass meter which enables the return flow to be detected, in accordance with the features of the preamble of claim 1.
Air mass meters which operate, for example, in accordance with the hot-film principle are used for detecting the air mass inducted by internal combustion engines. These usually have a heated element which is situated in the airflow to be measured and is cooled thereby. Since during operation of the internal combustion engine it is possible for conditions to arise under which pulsations can occur in the induction air, some air mass meters have temperature sensors with the aid of which the temperature difference upstream and downstream of a heating region can be determined so that it is possible to detect the direction of flow. It is also possible in the case of such air mass meters to define a characteristic having a range for returning air. In this case, characteristic is taken to mean the relationship between the output voltage of the air mass meter and of the air mass. Such an air mass meter is disclosed, for example, in DE-OS 43 24 040.
Despite the detection of the return flow, in the case of such an air mass meter the indication of the return flow is not completely correct when there is a pulsating air flow with a return flow. Normally, too low an air mass is indicated by the sensor or air mass meter. The reason for this resides in the thermal inertia of the measuring principle, which although relatively slight is present.
ADVANTAGES OF THE INVENTION
The method according to the invention and having the features of the main claim has, by contrast, the advantage that even in the case of the occurrence of return flows a very high accuracy of the air mass detection, and thus of the detection of the load value of the internal combustion engine is possible. This is rendered possible by virtue of the fact that the characteristic range of the air mass meter, which characterizes the pulsating operation of the internal combustion engine, is changed such that the average air mass indicated by the air mass meter corresponds in the case of pulsation with return flow to the actual air mass inducted by the engine.
Since the characteristic range of the return flow is reached exclusively in the case of pulsating operation of the internal combustion engine, a correction is advantageously carried out only when a return flow is detected. In the case of non-pulsating operation, the usual characteristic is employed, and no correction is then required.
Further advantages of the invention are achieved by means of the measures specified in the subclaims.
DRAWING
The invention is represented and explained in more detail below with the aid of the drawing in which, in particular,
FIG. 1a shows an air mass meter such as is disclosed, for example, in DE-OS 43 24 040, FIG. 1b shows a possible evaluation circuit,
FIG. 2 shows the characteristic of such an air mass meter, including the influences, according to the invention, on the characteristic, and
FIG. 3 shows a time characteristic of the pulsating air mass.
DESCRIPTION OF THE EXEMPLARY EMBODIMENT
In the known air mass meter represented in FIG. 1a, the sensor element 10 is arranged on a carrier 11. Said element is located in the flow of medium indicated by the arrow 12, that is to say, for example, of the flowing air in the induction pipe of an internal combustion engine.
The sensor element 10 in this case has a frame 13, made from monocrystalline silicon, as well as a dielectric diaphragm 14 on which a heater 15 and two temperature detectors 16, 17 and a heater temperature sensor 18 are arranged. The elements arranged on the sensor element 10 are connected via bonding pads 19 and bonding wires 20 to thick-film circuits which are located on the carrier 11 and consist of thick-film conductor tracks 21 as well as thick-film resistors 22, 23. The precise embodiments and the possibilities for variation are to be gathered from DE-OS 43 24 040 in this ca
REFERENCES:
patent: 4457167 (1984-07-01), Sumal
patent: 4478075 (1984-10-01), Oyama et al.
patent: 4527530 (1985-07-01), Abe et al.
patent: 4555937 (1985-12-01), Sumal
patent: 4571990 (1986-02-01), Honig
patent: 4669301 (1987-06-01), Kratt et al.
patent: 4694806 (1987-09-01), Wataya et al.
patent: 4719890 (1988-01-01), Wataya et al.
patent: 4774833 (1988-10-01), Weibler et al.
patent: 4884215 (1989-11-01), Zboralski et al.
patent: 5003950 (1991-04-01), Kato et al.
patent: 5014550 (1991-05-01), Gee et al.
patent: 5241857 (1993-09-01), Schnaibel et al.
patent: 5355726 (1994-10-01), Zurek et al.
patent: 5517971 (1996-05-01), Nishimura et al.
Hecht Hans
Konzelmann Uwe
Tank Dieter
Dombroske George M.
Robert & Bosch GmbH
Striker Michael J.
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