[cfg83]

Hello -

First a little background. In August I passed my emissions test :



My car passed with great numbers for HC and CO pollution (below the average !), but the NOx was higher than normal. I did have the HAI (Hot Air Intake) online, so maybe this is an effect of the (mild) lean-burn :



I didn't have the ScanGauge online, but I would guess at least 130+ degrees F HAI.

I also have an EFIE from Eagle Research (Eagle-Research:) that adds a voltage to the 02 sensor. This will also increase my lean burn and therefore my NOx.

Today I was posting in this thread ...

what do you think of hydrogen mods (with video)
what do you think of hydrogen mods (with video) - Fuel Economy, Hypermiling, EcoModding News and Forum - EcoModder.com

... and Lazurus pointed out my ethical dilemma :

Originally Posted by Lazarus

Have you had any reports on the emissions that is created when running lean? I wonder if the Nox goes through the roof or does the hydrogen do something to counteract that?

Now, here's my problem. I want to increase MPG and stay within my car's stated legal NOx limits. Because of this is I want to monitor my NOx in real-time. That makes "normal" smog station NOx sensor setups out of the question. Soooooooo, I have been roaming the net. Up to now I have only been able to find this :

Smart NOx Sensor
VDO - Smart NOx Sensor


The good part is that it is obviously designed for a car's harsh environment (it looks just like an oxygen sensor!). The bad part is that it doesn't seem to be for sale (yet), delivers a digital signal (a voltage is all I want), and probably costs an arm and a leg.

VDO engineered this sensor with NGK, and here is what they have to offer :

(NGK) Sensor Technology
NGK Automotive Ceramics U.S.A., Inc.


I like the NGK NOx sensor more because it seems to be offered in a non-smart (voltage only?) version.


Question : Does anyone know of NOx sensors for gasoline and/or diesel cars that are in the sub $100 range?


URL Appendix .......................................

Here are some other close-but-no-cigar leftover URLs from my googling :

New Sensor-Based Diesel Emissions Control System
Green Car Congress: New Sensor-Based Diesel Emissions Control System

Before IMITEC there was no NOx sensor for diesel engines, though such sensors do exist for gasoline engines. We essentially adapted that technology for diesel, so we can offer another option to engine manufacturers.

CO and NOx dual sensors (looks too flimsy for auto applications)
MiCS

MiCS 4514
This sensor contains two dedicated gas sensing chips, one for reducing gases (CO/HC) and one for oxidizing gases (NOx). The two chips are fully independent.

High-sensitivity, rapid-response nanotechnology NOx sensor
High-sensitivity, rapid-response nanotechnology NOx sensor

Conventional NOx sensors do not have sufficient robustness or heat resistance in the harsh environment of engine exhaust gases. To solve this problem, a multi-chamber sensor that uses a solid oxide electrolyte (oxygen-ion conductor) has been developed. This, however, inherently does not give a high-speed response, because it has a rather complicated structure and it measures NOx concentrations by combining multistep electrochemical reactions. This poses a problem in relation to the purification of exhaust gases and reduction of fuel consumption.

Geneva Motor Show: VW Touareg BlueTDI
Geneva Motor Show: VW Touareg BlueTDI - egmCarTech

The Euro-4 standard currently specifies a NOx limit of 0.25 g/km here. The US standard, which the Touareg BlueTDI satisfies, specifies among other things a NOx limit of 0.043 g/km (0.07 g/mile).

Emission Control Technologies for Off-Road Diesel Equipment
Manufacturers of Emissions Control Technology || Off-Road Diesel Equipment

NOx Sensor: NOx sensors represent state of the art technology that can be applied to gasoline lean burn engines as part of a broader engine control or diagnostic system used to insure proper operation of the NOx emission control system. These sensors can be incorporated independent of the NOx emission control technology used on the vehicle and their function is primarily to monitor the NOx conversion efficiency of the catalyst.

Keeping watch on car emissions
Keeping watch on car emissions

It is also possible to use sensors that respond directly to concentrations of the pollutant gases e.g. NOx. While these are common in test benches and workshops, they are too expensive to be fitted routinely to cars.

Toyota's DPNR System: how engines, catalysts, fuels make clean-diesel
Toyota's DPNR System: how engines, catalysts, fuels make clean-diesel | Diesel Fuel News | Find Articles at BNET

An air/fuel ratio sensor, exhaust temp sensor, and pressure differential sensor regulate catalyst regeneration, rather than a NOx sensor -- a lesson that today's pricey NOx sensors perhaps could be avoided.

Cummins seeks better NOx sensor for closed-loop emissions control
Cummins seeks better NOx sensor for closed-loop emissions control | Diesel Fuel News | Find Articles at BNET

A cheap NOx sensor that is capable of detecting as little as 20 ppm of NOx in real time exhaust is needed to hit EPA's 0.2 grams/bhp-hr NOx limit for 2007-2010, especially for urea-SCR, Cummins said at SAE Congress (see SAE 2002-01-0287). Cross-sensitivity to ammonia (for urea-SCR) could further hamper the effectiveness of a NOx sensor, researcher Qingwen Song explains.

NOx OBD Application (more details on the NGK sensor)
NGK EUROPE

The NGK NOx sensor for reducing NOx tail pipe emission is a stand alone component, it means no further calibration is required. Easy system integration can be done by CAN-BUS.
It can also be used for On-Board Diagnosis (OBD).

Thick Film Zro2 Nox Sensor for the Measurement of Low Nox Concentration
Thick Film Zro2 Nox Sensor for the Measurement of Low Nox Concentration

Abstract:
A practical ZrO2 NOx sensor using dual oxygen pumping cells has been introduced for the control of NOx emitted from a lean-burn gasoline engine and diesel engine. However, the mea accuracy was not high enough to be useful for controlling or monitoring a low level of NOx concentration such as several tens ppm behind a three-way catalyst or lean NOx catalyst which is NOx adsorption or De-NOx catalyst.

CarloSW2