公开(公告)号：US5310474A

公开(公告)日：1994-05-10

申请号：US912389

申请日：1992-07-13

申请人： Robert E. Hetrick ,  Allen L. Schamp

发明人： Robert E. Hetrick ,  Allen L. Schamp

IPC分类号： G01N27/00 ,  G01N27/62 ,  G01N27/26

CPC分类号： G01N27/002 ,  G01N27/626

摘要： A sensor for determining the stoichiometric air to fuel ratio (A/F) at the input to the cylinders of an internal combustion engine which is based on measuring the change in the workfunction of a material which occurs when the oxidizing and reducing species in the adjacent gas phase are at or near their stoichiometric ratio. In one method the sensor includes a material which is capable of thermionically emitting alkali metal or other appropriate ions into an exhaust gas atmosphere where they are subsequently collected by a nearby collector electrode and the magnitude of the emission current is measured. The interaction of the emitting surface with the gas phase reversibly changes the workfunction of the emitting surface from large to smaller values as that gas phase is varied through the stoichiometric ratio with respect to the amounts of the oxidizing and reducing species in the gas. Such a change in workfunction of the surface is accompanied by a change in the rate of the thermionic emission at the stoichiometric ratio thereby sensing that ratio in the gas phase which is proportional to the A/F at the input to the cylinders.

摘要翻译： 用于确定在内燃机的气缸的输入处的理论空燃比（A / F）的传感器，其基于测量当相邻的氧化和还原物质发生的材料的功函数的变化时 气相处于或接近其化学计量比。 在一种方法中，传感器包括能够将碱金属或其它适当离子热离子发射到废气气氛中的材料，其中它们随后由附近的集电极收集并且测量发射电流的大小。 发射表面与气相的相互作用可逆地将发射表面的功函数从大到小改变，因为气相相对于气体中氧化和还原物质的量的化学计量比而变化。 表面的功函数的这种变化伴随着化学计量比下的热离子发射速率的变化，从而检测气相中与气缸输入端的A / F成比例的比例。

公开(公告)号：US5275712A

公开(公告)日：1994-01-04

申请号：US913311

申请日：1992-07-14

申请人： Robert E. Hetrick ,  Allen L. Schamp

发明人： Robert E. Hetrick ,  Allen L. Schamp

IPC分类号： G01N27/41 ,  G01N27/00 ,  G01N27/60 ,  G01N27/62 ,  G01N27/26

CPC分类号： G01N27/626 ,  G01N27/002

摘要： A sensor determines a wide range of air-to-fuel ratio values (A/F) about the stoichiometric A/F in a gaseous mixture which has oxidizing and reducing species as might be found in an automotive exhaust. The sensor includes a surface that serves simultaneously as the working electrode of a solid-state oxygen concentration cell and as a surface whose workfunction changes from a higher to a lower value as the oxidizing and reducing species in the adjacent gas phase, and in interaction with the surface, pass from an excess oxidizing to the excess reducing condition about the stoichiometric ratio. In one embodiment, the surface exposed to the gas in question is the emitter electrode of a thermionic diode which emits positively charged alkali ions into the exhaust ambient where they are collected by a nearby collector electrode. Changes in the ratio of the oxidizing and reducing species about the stoichiometric ratio produce corresponding changes in the thermionic emission. Oxygen pumping to or from the working electrode modifies the thermionic emission in a systematic way to provide a pumping method of operation in which the magnitude of the pump current required to maintain the thermionic emission current at some preset value despite changes in the A/F ratio of the ambient leads to a relationship between pump current and A/F that can be used to sense the A/F.

摘要翻译： 传感器确定在气态混合物中大约有化学计量A / F的空气 - 燃料比值（A / F）的宽范围，气体混合物具有在汽车尾气中可能发现的氧化和还原物质。 传感器包括同时用作固态氧浓度电池的工作电极的表面，以及作为相邻气相中氧化还原物质的功函数从较高值变为较低值的表面，并且与 该表面从化学计量比的过剩氧化过渡到过剩还原条件。 在一个实施例中，暴露于所讨论的气体的表面是热离子二极管的发射电极，其将带正电的碱离子发射到排气环境中，在那里它们被附近的集电极收集。 氧化和还原物质的比例关于化学计量比的变化产生热离子发射的相应变化。 氧气泵送到工作电极或从工作电极泵送，以系统的方式改变热离子发射，以提供一种泵送方法，其中尽管A / F比率有所变化，仍将热电子发射电流保持在某一预设值所需的泵浦电流幅值 的环境导致泵电流和A / F之间的关系，可用于感测A / F。