Auto-Biography: Emblematic of Emissions

Undated photo showing LA smog in the late ’40s or early ’50s. (Source:


One of the significant contributors to what is sometimes referred to as the “Malaise Era” in automotive history was the industry’s need to comply with increasingly strict exhaust emissions standards.

A bit of background may be in order here: California’s first modern recorded “smog event” occurred in Los Angeles during the summer of 1943, reducing visibility to a reported three blocks and causing various health-related issues.  By the early 1950s, Caltech chemistry professor Dr. Arie Haagen-Smit found that gasoline-based hydrocarbons and oxides of nitrogen produced by internal combustion engines were the major constituents of smog (a term combining the words smoke and fog, coined not by Haagen-Smit, as is popularly thought, but by Dr. Henry Antoine Des Veaux in a 1905 scholarly paper presented at a Public Health Congress meeting in London).

Caltech professor Dr. Arie Haagen-Smit in a 1956 photo. (Source:


In 1966 California established the nation’s first tailpipe emissions standards, and one year later the California Air Resources Board (CARB) was established. Two years later, Germany’s Robert Bosch GmbH began to use elements of lambda-sensing technology to measure the oxygen content in lead smelters used in battery production –Stay with me here, and we’ll see how these disparate threads eventually come together.

Back in the U.S., the Federal Clean Air Act of 1970 placed pollution control under the purview of the Federal government, rather than the individual states. Moreover, it also authorized California to set its own separate, stricter vehicle emissions regulations to address that state’s climate, topography, population, and auto-centric lifestyle, all of which combined in the L.A. Basin to generate the nation’s worst air quality.

Two years later, speaking at an environmental conference in Stockholm, Sweden, Volvo’s then-CEO Pehr Gyllenhammar admitted that the automobile was a major contributor to increased air pollution. By the conference’s end, the Swedish automaker set out an environmental declaration that “Volvo is responsible not just for ensuring that its products are modes of transport that work well but also that they work in a broader context – in our environment.”

Volvo engineers found that the oxidizing catalytic converter, which was soon to be launched with the advent of unleaded gasoline, could also be modified to treat hydrocarbons (HC), carbon monoxide (CO), and nitrogen oxides (NOx) much more effectively than previously thought. This realization occurred not a moment too soon, as California introduced stricter auto emissions standards for 1977, mandating HC limits of 0.41 grams/mile, a CO limit of 9.0 grams/mile, and a NOx limit of 1.5 grams/mile.

In the SAE paper “Bosch Fuel Injection and Engine Management,” by Charles O. Pobst, the key supplier working on control systems for the so-called three-way catalyst explained that “…the three way catalytic converter works best when the air-fuel ratio is near stoichiometric, when lambda (the excess air factor) is within a very narrow range around lambda = 1. Fuel injection systems…cannot hold the air-fuel mixture within the required range. The necessary precision…requires a closed-loop control system. The source of this [additional] feedback is a lambda sensor (or oxygen sensor) installed in the exhaust system…The lambda sensor signal provides feedback to the fuel injection ECU, indicating …whether the air-fuel ration needs to be corrected. The system can then adjust its fuel metering so…the exhaust remains as clean as possible.”

A schematic showing the Lambda sensor’s location in the exhaust manifold. (Source: Volvo)


When the system, designed “Lambda Sond” (sond being the Swedish word for probe, or sensor) was introduced on the California-market 1977 model year Volvo 240s beginning in late 1976, Tom Quinn, then CARB chairman, called it “the most significant breakthrough ever made in the control of vehicle exhaust emissions.”  Indeed, test results showed the Lambda Sond-equipped cars registered 0.2 g/mile of HC, 3.0 g/mile of CO, and 0.2 g/mile of NOx emissions, handily beating the standard.

Volvo engineer Stephen Wallman, developer of the Lambda Sond oxygen sensor. (Source: Volvo)


My own small contribution to the Lambda Sond story started with a request to design a grille emblem for Volvos equipped with the technology. After some consideration and a number of idea sketches, I settled on a depiction of the Greek letter lambda, presented in Volvo blue with a bright outline, above the words “Lambda Sond”.

Realizing in the mid-seventies that the lambda symbol had taken on some newer connotations that might not have been on the radar of some of my colleagues (not to mention our department’s Swedish chief), I presented my design concept and hesitatingly noted the additional meanings the symbol had acquired, feeling my cheeks turning a slight shade of red in the process.

The big boss, silent at first, also began to turn crimson as he grasped the implications of my explanation. Nevertheless, he waved away any potential concerns, and the design was approved, eventually gracing the grilles of countless Volvos. I have to admit that I felt a distinct sense of accomplishment whenever I happened to notice that small badge in traffic on the road back in the day.

A mid-80s Volvo with my handiwork still attached. (Source:


(Featured image: New old stock (NOS) Volvo Lambda Sond emblems)