Home, Auto Repair Library, Auto Parts, Accessories, Tools, Manuals & Books, Car BLOG, Links, Index
I'm a boomer baby, born way back in 1950. WWII was over, the GIs had returned home and were buying homes in new subdivisions and buying new cars. The U.S. population at that time was 125 million, and the car population was only 25 million (1 car for every 5 people). At that time, cars had no emission controls whatsoever. Nobody saw a need for it back then, and the technologies we use today to reduce exhaust emissions did not exist and would not be invented for another 20 to 30 years!
Today it is a much different situation. The U.S. population has almost tripled (around 340 million) while the vehicle population has exploded to 292 million (over a 10x increase!). All new vehicles must meet strict vehicle emission standards. Today's internal combustion engines emit only a tiny fraction of the pollutants their ancestors released into the atmosphere, and are 98% or more cleaner than pre-emission vehicles.
Carbon Dioxide (CO), however, is still an issue. A very BIG issue! CO2 emissions are still the same today as they were 70 years ago from engines of similar displacement. Engines today have been downsized for fuel economy, but they still produce huge amounts of CO2 in the exhaust.
For every gallon of gasoline burned, 19.5 pounds of CO2 come out the tailpipe. According to the U.S. Environmental Protection Agency (EPA), the average car today produces about 4.6 metric tons of CO2 per year!
Technically, CO2 is not a traditional pollutant because it is nontoxic and does not play a role in the creation of urban smog. But it does play a significant role in Global Warming and Climate Change by trapping heat in the atmosphere (the so-called "greenhouse effect"). Current emissions technology does not reduce CO2 in the exhaust, and to date there is no simple technology that can do that. The only way to reduce CO2 is to use a fuel that does not contain any carbon (such as hydrogen gas). But that's another story.
When I graduated from high school in 1968, car culture was everywhere. It was the era of suburban subdivisions, urban sprawl, shopping centers and muscle cars. Cars were a must for shopping, commuting and fun. Cars were cool! Muscle cars got their start with the Pontiac GTO in 1964, followed by the introduction of the Ford Mustang in 64/65, the big block Chevy Chevelle SS, followed by cars such as the Dodge Charger in '66 and Chevy Camaro in '68.
The first automotive emission controls were also introduced during this time. In 1965, California vehicles required to have Positive Crankcase Ventilation (PCV) systems that routed crankcase vapors back into the engine rather than just venting hem into the air. In 1968, federal emission rules required PCV for all cars in the U.S.
At that time, air pollution wasn't a major issue for most large metro areas because the vehicle population was only a tenth of what it is today. Even so, Los Angeles did have a very serious air quality problem because of its geography, sprawl, lack of good public transportation and its total dependence on the automobile.
Los Angeles is surrounded by mountains and faces the ocean. The mountains around LA tend to trap hot air over the city, causing airborne pollutants from car exhausts, industrial sources, power generation and oil wells to concentrate and form smog.
Smog forms when unburned hydrocarbons (HC), oxides of nitrogen (NOx) and carbon monoxide (CO) react with sunlight. It also creates ozone, which is a highly reactive and irritating form of oxygen. Ozone is bad news because it causes headaches, coughing, dry throat, shortness of breath, a heavy feeling in chest, and fluid in the lungs. Higher levels of exposure to ozone can lead to more severe symptoms while chronic exposure may lead to asthma.
The California Air Resources Board (CARB) was created in 1967 to come up with solutions for LA's smog problem. CARB spearheaded efforts to develop automotive emission control rules and test procedures. They pioneered all of the various emission control requirements that would eventually become law nationwide, and instituted the first vehicle inspection program to check vehicles for smog compliance.
One of the first steps to reduce pollutants from vehicles was installing PCV systems. Smog pumps were also installed on some vehicles to help reduce unburned hydrocarbons in the exhaust. Then came Exhaust Gas Recirculation (EGR) in 1973. EGR's purpose was to reduce oxides of nitrogen (NOx) emissions when an engine was working hard under load or accelerating. NOx forms when combustion temperatures rise above 2500 degrees F. Nitrogen, which makes up 78 percent of the air we breathe and is normally inert during combustion reacts with oxygen to form nitrous oxide (NO). When nitrous oxide in the exhaust exits the tailpipe, it reacts with sunlight and combines with more oxygen to form nitrogen dioxide (NO2). This is the brownish haze that contributes to urban smog. It is toxic and can cause eye irritation, breathing problems and long term health effects with prolonged exposure.
The next BIG change, and I mean really BIG change, came in 1975 when Catalytic Converters and unleaded gasoline appeared. The catalytic converter was a real game changer in terms of significantly slashing tailpipe emissions of HC, CO and NOx. But there was a problem. You couldn't burn leaded fuel in a vehicle with a catalytic converter because lead would quickly contaminate the catalyst inside the converter, rendering it useless. Consequently, leaded gas had to be replaced with more expensive unleaded gas for the converter to function and survive.
Tetraethyl lead had been used as a cheap Octane boosting fuel additive since 1923. General Motors teamed up with DuPont to promote the use of leaded gasoline as a means of boosting performance and fuel economy. Higher octane fuel meant engines could be built with higher compression ratios which allowed up to 20 percent or more horsepower, faster acceleration and 10 to 20 percent better fuel economy. It seemed like a win-win solution at the time. As an added benefit, lead also acted as a lubricant to extend engine valve life.
Even so, there were some trade-offs with leaded gasoline. It tended to foul spark plugs over time, requiring yearly spark plug replacements and tune-ups. Lead is also a toxic heavy metal, but GM and DuPont downplayed the potential health concerns by stating it was only used in very small amounts in gasoline.
As time went on and the car population got larger and larger along with urban traffic and congestion, lead poisoning because more and more of a public health concern. Children are especially susceptible to lead poisoning, and it was found that children living in many large urban areas had an alarming amount of lead in their blood. High lead levels can inhibit mental development in addition to causing physical harm. So a little over 50 years after its introduction, the decision was made to gradually phase out leaded gasoline in the U.S. It didn't happen overnight, and took nearly 20 years to disappear entirely in the U.S., and it wasn't until 2021 that the rest of the world finally phased out tetraethyl lead as an octane-boosting gasoline additive.
The next BIG change in automotive emissions control came in 1980-81 with the introduction of Computerized Engine Control Systems. This really changed things up by allowing engines to essentially become self-tuning with adjustable spark timing and fuel mixtures. Computerized engine controls also eliminated the need for annual tune-ups, which reduced maintenance costs while allowing engine to run cleaner. Variable fuel ratios also enabled catalytic converters to operate more efficiently. The net result was that automotive tailpipe emissions of HC, CO and NOx plunged by over 98 percent compared to pre-emission controlled vehicles.
There was quite a learning curve for automotive technicians and do-it-yourselfers to get up to speed on the new computerized engine control systems, but gradually the new technology was learned and mastered (although with much grumbling and whining!).
Another big change that came with computerized engine controls was the ability of the system to self-diagnose faults. Troubleshooting engine performance and emissions problems could be very difficult with these complex systems, so auto makers developed software that could monitor the various sensor inputs and system outputs to detect problems. The trouble was, up until 1996 every vehicle manufacturer had their own approach to engine control and emission diagnostics. They all had different self-generated trouble codes, different methods for reading codes, and different scan tools for accessing the computer. For independent repair shops who made their living serving all makes and models of vehicles, it was a nightmare because it required so many different scan tools and diagnostic procedures.
The fix for this problem came in 1996 when Onboard Diagnostics II became law in the U.S. OBDII rules required all vehicle manufacturers to have standardized (generic) fault codes in addition to their own proprietary codes, a universal 16-pin onboard diagnostic connector, and the ability to use a standardized OBDII scan tool to read the codes and access vehicle system data.
Over my working lifetime, I've seen the first emission control rules in California spread to the entire U.S., and beyond to the entire world. The European Union developed their own emission rules based on much of the progress that was made here, and many of these rules in one form or another have been adopted in Asia and other areas of the world. But such rules have become necessary because of the explosive growth of cars (and people) worldwide.
Today there are about 8 BILLION people on the earth. China and India both have about 1.5 billion people in their countries (that's 10 times the population of the U.S.!). Most of these people used to walk and ride bicycles. Now they all want to drive cars. Consequently, the world now has about 1.5 BILLION cars and light trucks, 98 percent of which are powered by gasoline or diesel internal combustion engines. Less than two percent of the world's vehicle population is currently electric. The growth in the vehicle population in the U.S. and Europe has mostly leveled off, but it is continuing to expand at double digit rates in much of the rest of the world (especially in China).
The impact on the climate by all of these ICE engines burning fossil fuels is a HUGE increase in Carbon Dioxide (CO2) Emissions .
Until recently, CO2 was considered to be a "harmless gas" and not an air pollutant. CO2 is the natural byproduct of combustion when any fuel containing carbon is burned (gasoline, diesel, coal, wood, propane, methane, kerosene, jet fuel, you-name-it). We exhale carbon dioxide with every breath we take. But never in human history has CO2 emissions risen so much and so quickly. The last time levels were as high or higher than they are today was back in prehistoric dinosaur times. The rapid rise in atmospheric CO2 has been well documented, and is attributed almost entirely to human activity. Forest fires, volcanoes and other natural sources also emit large quantities of CO2, but plants and algae absorb much of the CO2 for growth via photosynthesis to maintain an environmental balance. The oceans also absorb a lot of CO2. But this delicate balance has been upset and knocked out of balance by our massive consumption of fossil fuels, which scientists say is causing Global Warming and Climate Change.
The world consumes over 100 MILLION barrels of oil a day! That's a tremendous amount of crude oil, and does not include all the natural gas (methane), coal and wood that is consumed daily for heating and industrial uses.
Scientists first started sounding the alarm bells back in the 1950s when they measured a gradual increase in average global temperatures that closely correlated with a gradual increase in atmospheric CO2 levels. At first, it was attributed to natural heating and cooling cycles in the earth's weather, which has undergone numerous freezing and thawing cycles going back millions and millions of years. The most recent "ice age" or glacial period occurred between about 120,000 and 11,500 years ago. Since then, Earth has been in an interglacial period called the Holocene with more moderate temperatures.
The rise in CO2 levels began with the Industrial Age 1760 to 1840), when people began using coal to power everything from industrial manufacturing to train locomotives. Atmospheric CO2 levels pre-industrial age were around 280 parts per million (ppm) or less. How do scientists know that? From examining tiny air bubbles trapped in ice cores taken from ancient glaciers. Today, average CO2 levels have topped 420 ppm, and occasionally go higher depending on the season and location.
There's no magic catalytic converter or add-on pollution control that can eliminate CO2 from car exhausts. But there are a variety of ways to reduce CO2 emissions with today's technologies.
1. The simplest and easiest way to cut CO2 emissions is to drive less. Consolidate trips, use public transportation more, and bicycle or walk more when and where possible.
2. Downsize engine displacement. A smaller engine burns less fuel and produces less CO2. Auto makers have been downsizing engines for over a decade or more. Most V8 engines as well as many V6 engines in passenger cars, mid-size and compact SUVs, and even some pickup trucks have been replaced with four-cylinder and even some three-cylinder engines. Even so, they all still emit a lot of CO2.
3. Hybrid vehicles can reduce CO2 emissions for shorter trips (up to 15 to 30 miles depending on the system's capabilities) by driving the vehicle electrically rather than by burning gasoline. But hybrids add cost and complexity to a vehicle's powertrain, and they still produce a lot of CO2.
4. Switching to a new carbon-free fuel source such as hydrogen. Toyota is pushing this as a possible option. But hydrogen has a lot of drawbacks such as its low energy density, limited range and requirement to be stored in heavy, high pressure or cryogenic cylinders. Hydrogen made from natural gas (methane) is expensive and energy intensive and produces carbon emissions, while hydrogen made from water by electrolysis is expensive and requires a green energy source (solar, wind or geothermal) to be carbon neutral. There is also virtually no infrastructure currently for hydrogen storage or refueling.
5. The ultimate solution, obviously is to phase out as many ICE engines as possible and switch to electric vehicles. EVs emit ZERO CO2 and ZERO pollutants because no fuel is being burned and there is no exhaust. And if the EV battery is recharged by wind, solar, geothermal or nuclear, it is carbon neutral. Of course, if it is charged by a conventional coal or natural gas-fired power plant there will still be carbon emissions produced - but much less than that of millions of ICE engines burning gasoline or diesel.
During my working career, I've authored three books about automotive emission controls (two of which were used as school textbooks!). I also wrote an extensive two-part training manual for a leading aftermarket chain of automotive tune-up and repair shops, plus a self-training and diagnostic guide to automotive emission controls, and probably a hundred or more in-depth technical articles on emission control diagnostics and repair. So I think I know what I'm talking about when I say the internal combustion engine has come about as far as it can in terms of increasing efficiency and decreasing emissions.
We have engines with variable displacement (cylinder deactivation) variable valve timing, even variable displacement. We have engines with both port and direct fuel injection, and turbochargers to boost power outputs. But thermal efficiency remains a major issue for ICE engines. Why? Because they use heat to drive a piston inside a sealed cylinder. This means up to a third of the energy produced by combustion is absorbed by the engine itself, which requires a cooling system to keep things from melting down. Also, when each cylinder does its exhaust stroke, it pushes hot exhaust gases that are still expanding out the tailpipe, which wasted up to a third of the potential energy in the fuel that was just burned. Consequently, most IC engines waste nearly two-thirds of the energy from each gallon of fuel that is burned.
Many attempts have been made to overcome this problem. Back in the 1980s, there was a lot of research into high temperature ceramics for pistons, valves, even the engine block and head itself. Ceramics are light weight, wear resistant and can withstand temperatures that would melt almost any metal. But ceramics are also brittle, tricky to cast and machine, and not really a good material for the block and head of an ICE engine. Ceramic coatings can help retain heat in the combustion chamber for a slight improvement in thermal efficiency.
The idea behind using ceramics was that higher temperature materials would allow the engine to run hotter without melting down, eliminating the need for a cooling system. Even so, this would not solve the problem of heat loss out the tailpipe, but it would in theory increase thermal efficiency maybe 20 to 30 percent overall. But as they soon learned, gasoline wouldn't work at such high temperatures due to pre-ignition and detonation. Such temperatures might even be too high for conventional diesel fuels. Research is still going on but to date I have not seen any big breakthroughs that would make a significant difference in thermal efficiency, let alone any reduction in CO2. NOx emissions are also a real problem at elevated temperatures, which also limits the potential of a ceramic engine.
There has been a lot of work done with turbine engines, but turbines are not a practical option for most automotive applications because of their poor fuel economy. it would also be very challenging to fit some type of exhaust emission controls on a turbine, since it relies of a free flow of hot combustion gases at high velocity to spin a turbine. And turbines produce just as much if not more CO2 as ICE engines.
So considering where we have been and how far we have come with automotive emission controls, it seems painfully obvious that the next step in the evolution of automotive emission controls is to transition away from ICE engines to electric vehicles.
EVs need no catalytic converters, EGR or PCV valves, no computers or sensors to self-adjust fuel mixtures or spark timing, no add-on evaporative (EVAP) emissions control system to capture and store fuel vapors, no Check Engine Light or periodic emissions inspections because there are no emissions to control or check. Electric motors are also 94 percent or higher efficient so most of the energy they consume is actually used to push the vehicle down the road.
EV battery technology and the charging infrastructure to keep these vehicles going still have a long way to go, but we'll get there. It's only a matter of time. ICE engines have had over 120 years of development and evolution to reach the point where they are today. Nissan’s Leaf was the first mass produced electric car to hit the U.S. market back in December 2010, followed by Tesla’s Model S in 2012. It has only been the past couple of years that other auto makers have introduced various EV models of their own.
Over a million EVs were sold in the U.S. in 2023, and hopes are EV sales will nearly double in 2024. It’s not an overnight transition but it is happening. Sales have not been as brisk as auto makers would like them to be for a variety of reasons.
\Sticker prices for new EVs are still too high but are coming down thanks to government incentives, rebates and sales pressure from the used EV market.
Many potential EV buyers are still concerned about range, how long it takes to recharge the battery, the availability of public charging stations, and the longevity of the high voltage battery. But the data shows that most EV batteries are holding up extremely well, even beyond 150,000 miles. EV batteries are also improving with every new model year with more efficient cell designs and less dependence on expensive metals such as cobalt and nickel. Some of the newest EVs have batteries that can be charged from 20 to 80 percent in 15 minutes or less using high voltage/amperage superfast chargers.
Governments, auto makers and private enterprise are also making significant investments in expanding the availability of public charging stations, especially in rural areas where few currently exist.
Things are getting better and will continue to improve as we go forward into the new EV era. Some people (myself included) don’t like change, but there is no going back. The world’s auto makers have invested billions of dollars into developing new EV models and retooling their plants to produce the next generation of emission-free vehicles. It’s the beginning of the end for the internal combustion engine and the beginning of the era of zero emission transportation.
The transition leaves me with mixed emotions because I grew up muscle cars and ICE engines. I’ve been writing about ICE engine technology my entire professional career. But the time has come to kiss this mature and soon to be obsolete ICE technology goodbye and embrace what’s coming down the road. Farewell old friend. It’s been a good ride.
Related Articles: