Measuring and testing – Liquid analysis or analysis of the suspension of solids in a... – By vibration
Reexamination Certificate
1999-12-16
2001-06-26
Kwok, Helen (Department: 2856)
Measuring and testing
Liquid analysis or analysis of the suspension of solids in a...
By vibration
C073S061490
Reexamination Certificate
active
06250137
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to the measurement of gasoline volatility characteristics, and more particularly to an ultrasonic-type gasoline characteristic determination method and apparatus capable of determining the volatility characteristics with good accuracy by measuring the velocity of an ultrasonic wave in a gasoline containing alcohol or other additives and by compensating for deviations from a reference temperature.
2. Description of the Prior Art
Among the characteristics of automotive gasolines, the ability to resist knocking in engines is one of the important quality-determining characteristics. To increase this anti-knocking ability, tetra ethyl lead (TEL) is added, but in recent years, gasolines containing about 10% ethyl alcohol instead of TEL have been used in the United States and other countries.
Gasoline, in itself, is not always uniform, but there are variations in its volatility (combustion properties). The T50 value used to describe this volatility indicates the temperature at which 50 percent of the gasoline evaporates, the T50 value being lower for lighter gasolines. In accordance with this T50 value, i.e., volatility, engine control must be optimized. For example, if the volatility before engine startup can be determined, it becomes possible to minimize the amount of fuel increase during engine startup and thus reduce emissions during the startup.
In particular, gasolines used in the United States have varying degrees of volatility, and it is essential to optimize engine control according to the volatility. The need therefore arises for a sensor capable of monitoring gasoline volatility. The T50 value that serves as a measure of gasoline volatility is estimated from gasoline density. This density is calculated from the propagation time of an ultrasonic wave.
In Japanese Unexamined Patent Publication (Kokai) No. 7-225228 as one prior art pertaining to this field, a detection device is installed midway through a gasoline pipeline, and noting the fact that gasoline volatility tends to become higher for softer gasolines with lower densities, the propagation delay time of an ultrasonic wave is detected to obtain the gasoline density, thus measuring its volatility properties and estimating the T50 value.
This method, however, has not been sufficient in terms of accuracy since for gasolines containing additives such as alcohol, the relationship between the density and the T50 value is not constant but an inversion occurs. There is therefore a need for a simple gasoline property determination method and apparatus with improved accuracy.
SUMMARY OF THE INVENTION
An object of the present invention is to study a method that involves measuring the velocity of an ultrasonic wave to determine the volatility of gasoline containing alcohol or other additives, and to provide an ultrasonic-type gasoline characteristic determination method and apparatus that are free from deviations of the kind inherent in the prior art which relies on the relationship between density and T50 value, and that achieve high accuracy.
Another object of the invention is to study ways of compensating for temperatures at the time of measurement in the above determination method, and to provide an ultrasonic-type gasoline characteristic determination method and apparatus that enable the variation with temperature of the propagation distance of an ultrasonic wave to be cancelled by utilizing the resonance characteristic or the reflected wave strength of the ultrasonic wave.
A further object of the invention is to study ways of compensating for temperatures at the time of measurement in the above determination method, and to provide an ultrasonic-type gasoline characteristic determination method and apparatus that enable the variation with temperature of the propagation distance of an ultrasonic wave to be cancelled by utilizing a thermal contraction spring or the expansion of a gas and thereby varying the propagation distance of the ultrasonic wave.
The gist of the present invention is summarized as follows:
(1) An ultrasonic-type gasoline characteristic determination method for determining gasoline volatility characteristics by using an ultrasonic wave, comprising the steps of transmitting an ultrasonic wave into a gasoline being measured, measuring the velocity of the ultrasonic wave in the gasoline, and determining the volatility characteristics of the gasoline from the velocity.
(2) An ultrasonic-type gasoline characteristic determination method according to item (1), wherein the volatility characteristics of the gasoline are determined after temperature-compensating the velocity of the ultrasonic wave against a reference temperature.
(3) An ultrasonic-type gasoline characteristic determination method according to item (2), wherein the temperature compensation is performed by measuring the resonant frequency of a substance immersed in the gasoline.
(4) An ultrasonic-type gasoline characteristic determination method according to item (2), wherein the temperature compensation is performed by measuring the reflected wavestrength of the ultrasonic wave in the gasoline.
(5) An ultrasonic-type gasoline characteristic determination method according to item (2), including the steps of transmitting an ultrasonic wave into a gasoline being measured as well as into a reference substance, measuring the velocity of the ultrasonic wave in the gasoline and the reference substance, and temperature-compensating the velocity of the ultrasonic wave in the gasoline against the reference temperature on the basis of the velocity of sound in the reference substance, and including distance varying means for correcting distance on the basis of the temperature-compensated ultrasonic wave velocity.
(6) An ultrasonic-type gasoline characteristic determination method according to item (3), wherein the substance immersed in the gasoline is a transducer.
(7) An ultrasonic-type gasoline characteristic determination apparatus for determining gasoline volatility characteristics by using an ultrasonic wave, comprising a transducer for transmitting and receiving an ultrasonic wave in a gasoline, and distance varying means for correcting the distance between the transmission and reception of the ultrasonic wave on the basis of the temperature of the gasoline.
(8) An ultrasonic-type gasoline characteristic determination apparatus according to item (7), including a first reflecting plate constructed from a low thermal expansion member and a second reflecting plate constructed from a high thermal expansion member, for reflecting ultrasonic waves transmitted from an ultrasonic wave transmitter, ultrasonic wave receiving means for receiving the ultrasonic waves reflected from the first reflecting plate and the second reflecting plate, means for detecting the propagation times of the waves reflected from the first reflecting plate and the second reflecting plate, and thereby obtaining an ultrasonic wave velocity temperature-compensated against a reference temperature, and means for detecting the volatility characteristics of the gasoline from the temperature-compensated ultrasonic wave velocity.
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Susumu Sakagami, et al. “Fuel Property Detection Using Fuel Density”, Automobile Technical Institute, No. 952, May 1995, pp. 199-202.
Ishikiriyama Mamoru
Kondo Takuya
Okazaki Toshihiro
Saitou Hiroaki
Takahashi Toshimitsu
Kwok Helen
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Toyota Jidosha & Kabushiki Kaisha
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