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Conference report: 2026 WCX SAE Congress

24 April 2026

The WCX SAE Congress was held on April 14-16, 2026, in Detroit, Michigan. The technical program included 485 peer-reviewed technical papers, about 100 oral-only presentations, and several panel discussions covering all areas of automotive technology, as well as an exhibition. The Congress formula has been changed, reflecting the ongoing economic challenges faced by the global auto industry. The first day of the Congress was limited to two keynotes and three top-level technology panels held in the exhibition area. The exhibition itself was shortened by a day, to the first two days of the event, while technical papers and panel discussions were presented during the second and third day. There were about 3,000 registered participants.

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The Congress opened with a keynote titled China Is Driving the Global Car Industry... Off the Cliff by Gordon Chang, an American political analyst and writer. The speaker discussed the multiple problems faced by Chinese economy—including high levels of debt, low fertility rates and shrinking workforce, economic drag from a slumping real estate sector, and industrial overcapacity forcing manufacturers to reduce prices and expand exports—including electric vehicles, batteries, and solar panels. China is now selling EVs around the world, forcing change in the global automotive industry. However, as war is spreading and the world is deglobalizing, the Chinese export powerhouse will face more problems and barriers to growth.

While the keynote focused on the threats to China’s economy, it brushed over its strengths. These were mentioned on several occasions in the following discussion panel—aptly titled Engineering a Resilient Propulsion Strategy in a Volatile, Uncertain, Complex, and Ambiguous World—with the participation of car makers (Ford, Stellantis) and industry analysts, and moderated by Chris Atkinson [Ohio State University]. China is overtaking the United States as an economic power, fast closing in on it as a military power, and it managed to abet the US move away from rare earths, while developing a near-monopoly on the processing and refining of several metals and minerals used in electric vehicles, batteries, weapon systems, and other advanced technologies. China has become the global center of excellence and a leader in the EV industry. Chinese vehicles—exported from China or manufactured in other countries—are affordable, while in the United States, most consumers can no longer afford to buy an American-made new car.

Discussing the future of hybrid vehicles, most panelists thought that hybrids will remain a viable powertrain option for many years, as opposed to being a bridge technology to all-electric vehicles.

Another keynote speech was given by Peter Simshauser, Chief Counsel, US National Highway Traffic Safety Administration (NHTSA), who talked about the current activities of the agency. A key NHTSA project is to update vehicle safety standards to accommodate automated vehicles (AVS). NHTSA believes that AVS technologies have a potential to improve vehicle safety and reduce fatalities. NHTSA is also in the process of re-setting CAFE fuel economy standards. The speaker emphasized that NHTSA standards should not be used as a tool to mandate the electrification of the vehicle fleet—this is inconsistent with how the Congress designed the standards, which were intended to cover internal combustion engine vehicles.

Technical sessions on engine and emission technologies opened with a technical panel titled A Year in Review on Emissions, Fuels, and Propulsion. Among the panelists, Chris Sharp [Southwest Research Institute] talked about recent regulatory developments, Allen Schaeffer [Engine Technology Forum] about recent trends in engine and powertrain development, and Jim Szybist [Oak Ridge National Laboratory] about transportation fuels.

The key regulatory trend, particularly in the United States, has been a change of direction—from tightening to the relaxation of emission requirements. The list of significant de-regulatory actions includes the repeal of GHG emission regulations, relaxation of CAFE fuel economy standards, moves to remove or limit California emission regulations, and the relaxation of EPA driver inducement requirements for vehicles with SCR systems. The anticipated coming actions by the US EPA include:

Key trends in internal combustion engines (ICE) technology include new investments and new engine developments, as governments adopt more supportive policy and reduce or eliminate EV mandates and subsidies, creating a more level playing field for various types of powertrains. Significant opportunities exist for applying advanced technologies to further improve fuel economy and lower emissions from ICEs. Hybrid technologies receive particular attention, as they have the potential to further reduce fuel consumption and CO2 emissions at a relatively modest investment. Other important energy and emission reduction technologies include high efficiency gasoline engines—with thermal efficiency already approaching 50%—and renewable fuels.

As US policies prioritize increasing energy availability, renewable fuels increase their contribution to transportation fuels. The US EPA has finalized the renewable fuels volumes for 2027, significantly increasing the volume obligations for biomass-based diesel fuels (biodiesel and renewable diesel). The volumes of ethanol, on the other hand, remain relatively flat, as the Reid vapor pressure (RVP) of ethyl alcohol remains a key barrier preventing the widespread use of E15 fuels. An important change in the US renewable fuels tax credit system, introduced by the OBBBA act, is that only American-controlled companies using feedstocks from America can qualify for tax incentives.

High Efficiency IC Engine Concepts

IAV has developed a technology package for an 11.6 L heavy-duty on-road gasoline engine for a Class 8 truck application that can meet EPA 2027 emission limits. The concept uses EGR and operates at λ = 1 across the entire engine map. A close-coupled three-way catalyst with a 40 L monolith and integrated coated particle filter forms the aftertreatment system. Spark timing retard is used to ensure rapid catalyst light-off. The engine features an innovative combustion chamber geometry, a 16.3 compression ratio with Miller intake valve timing, high EGR compatibility (up to 30%) within the real engine operating range using cooled low-pressure EGR, and an optimized crankshaft drive. Boost is provided by a single stage turbocharger with a wastegate. The engine yielded a 43.1% BTE with an extended map range where BSFC is less than 200 g/kWh. In a simulated US heavy-duty RDE cycle, the average fuel consumption was 228 g/kWh (vs. 217.5 g/kWh for a 15 L diesel engine). A reduction in total operating costs of $86,600 over the vehicle’s service life of 750,000 miles was estimated for the US market [6742].

Eaton, Fiat, Oak Ridge National Laboratory and AVL reported on a program targeting a 90% NOx reduction from the nonroad Tier 4 standard and 10% fuel savings compared to the existing Tier 4 Fiat Cursor 13 nonroad engine. A prototype engine was developed from a Fiat Powertrain XC13 onroad production engine. Compared to the Cursor 13, engine updates included a high compression ratio (~20.6:1), increased fuel-rail pressure, low-friction piston rings, a high-efficiency variable-geometry turbocharger, cylinder deactivation and a 48V EGR pump. The EGR pump was required to ensure EGR flow due to reduced exhaust pressure from the CDA. Two aftertreatment system configurations with a LO-SCR (TiV) and main SCR (Fe/Cu) catalyst were evaluated. ATS1 consisted of DOC+DEF1+LO-SCR+ASC+DOC+DPF+DEF2+SCR+ASC. In ATS2, an electric heater was placed between the first urea injection (DEF1) and the LO-SCR. A “next generation” mixer after DEF 2 was required for the downstream SCR. The electric heater was required to elevate the exhaust temperature at the LO-SCR early in NRTC cycle and provide a NOx reduction relative to the baseline engine. NOx emissions over the composite NRTC were 0.076 g/kWh and 0.021 g/kWh for the baseline and prototype with ATS2 respectively. The latter represents a 94.8% NOx reduction from the Tier 4 standard. A 15.7% fuel savings on the composite NRTC was achieved with the prototype with ATS1 compared to the baseline engine [6743].

Work carried out the University of Wisconsin-Madison, Purdue University and John Deere incorporated an e-supercharger downstream of the stock turbocharger on a Deere 4.5-L 4-cylinder diesel engine to create a two-stage boosting system and used it to evaluate two model-based control strategies for e-supercharger control during engine transients—a single-input single-output (SISO) controller with AFR as the input and e-supercharger speed as the output and a multiple-input multiple-output (MIMO) controller that controlled the EGR valve, exhaust throttle, e-supercharger speed, bypass valve, and the commanded fueling to achieved targeted AFR, engine speed and diluent-air-ratio. The engine demonstrated significant improvements over the baseline engine with both control approaches with an improvement of as much as 59.4% in the rate of transient power generation that resulted in reduced engine speed droop and decreased engine speed recovery time. Transient engine-out soot emissions were also reduced. The MIMO controller showed the greatest potential for future improvements [2026-01-0444].

Work at Tongji University investigated options to achieve 50% ITE in a gasoline engine. With natural aspiration, increasing the effective compression ratio to 15.8 and λ to 1.4 achieved an ITE of 40.3%. Deploying an active pre-chamber enabling ultra-lean combustion (λ=2.0) achieved an ITE of 43.3% while reducing NOx emissions. Under boosted intake pressure and a Miller cycle, elevating intake pressure to 282 kPa and achieving ultra-lean combustion (λ=2.0–2.2) resulted in ITE over 50%, with NOx emissions consistently below 50ppm [2026-01-0300].

Researchers from Toyota examined the effects of ethanol blending in a super-lean-burn engine. They found that thermal efficiency increased with ethanol content, due to reduced cooling losses. They also observed that while knocking was mitigated by the higher RON from ethanol blending, the effect was smaller than in the production engine operating at λ = 1. At λ = 2.5 and in-cylinder pressures above 9 MPa, the 50–90% combustion duration was prolonged due to suppressed ethyl radical formation and the greater influence of the reaction in which methyl radicals consume hydrogen atoms to produce methane [2026-01-0303].

Hyundai Motor Co. investigated the potential for improved fuel efficiency in SI engines via engine cooling system optimization for potential Euro 7 application. A single loop cooling system was chosen to ensure more uniform cylinder temperatures and avoid the need for a conservative ignition timing retard strategy sometimes required by split cooling systems to avoid knock. Measures taken to improve cooling system performance included reducing the thermal mass of the coolant circuit, optimizing control logic and valve opening strategies and enhancing zero-flow operation. A 0.67% improvement in fuel efficiency over the WLTP was achieved while improving cabin heating performance [2026-01-0297].

Emission Aftertreatment

Several papers discussed new developments in SCR technology—driven in part by the upcoming US EPA 2027 emission standards for heavy-duty engines that will require more active and more durable SCR catalysts. Cummins characterized the performance of a state-of-the-art Fe/zeolite SCR catalyst [6734]. Measurements in a laboratory reactor investigated the impact of extreme hydrothermal aging (HTA) up to 950°C for the fast (NO2:NOx = 0.5) and standard (NO2:NOx = 0) SCR reactions. The catalyst showed excellent durability for the fast SCR reaction but the catalyst activity decreased with increasing HTA for the standard SCR conditions. The study also assessed the impact of water vapor and the isothermal desorption of NH3 on catalyst performance.

Another study by Cummins investigated the effects of sulfur on ammonia slip catalysts (ASC) in diesel aftertreatment systems [6733]. A dual layer ACS was studied, with the top layer composed of Cu/SSZ-13 and the bottom layer of Pt/Al2O3. Two mechanisms of catalyst deactivation by sulfur have been identified. In one mechanism, sulfur in the feed gas interacted with NH3, with an immediate deactivation effect. After SO2 addition was stopped, the ASC recovered its activity and the ammonia slip returned to zero. Another deactivation mechanism involved a gradual catalyst poisoning by sulfur adsorbed in the catalyst washcoat.

BASF presented a multifunctional catalyst (MFC) that combines two functions: NH3-SCR NOx reduction and HC oxidation—while avoiding the oxidation of NH3 (in hydrogen engines, the MFC could simultaneously reduce NOx and oxidize H2) [6732]. The MFC incorporates two separate components, Cu/Z for the SCR function and Pd for the oxidation function. The catalyst was reported to show SCR activity comparable to a stand-alone SCR at temperatures up to about 400°C (at higher temperatures, the MFC oxidized NH3), while simultaneously producing an HC oxidation exotherm. The MFC catalyst can be used as a stand-alone device or coated on a particulate filter (then referred to as MFCoF). The desulfation of the MFC was conducted at 450-550°C, with the desulfation process greatly enhanced in the presence of HCs.

Low temperature SCR performance can be enhanced using various types of electric heaters in the urea dosing system. Emissol developed a compact, low-cost electrically heated mixer (EHM) unit that—in combination with a light-off SCR catalyst—allows meeting US EPA 2027 NOx limits and other stringent NOx emission regulations [6731]. Emission results were presented using a 5 kW EHM unit on a 15 liter heavy-duty diesel engine.

FPT Powertrain Technologies discussed an electrically heated urea vapor module (UVM) for off-road engines. The unit accelerates urea evaporation and raises the SCR temperature utilizing resistive wire wrapped around a urea mixing pipe. A 20°C gain in NOx conversion light-off temperature was reported on an XC13 13-liter engine with the heater power consumption at 2.2 kW.

Two talks by Cummins discussed the application of urea-SCR aftertreatment in heavy-duty, lean-burn hydrogen fueled engines. The presentations examined the effects of H2-ICE conditions—including high water vapor content and the presence of hydrogen—on Cu-zeolite catalysts [6728] and demonstrated compliance with the US EPA 2027 NOx, N2O, and PM emission standards using urea-SCR and a diesel-style electric heater [6729]. It was shown that while the composite cycle NOx emissions in a hydrogen engine are lower compared to diesel, transient NOx spikes are higher. Managing NH3 storage in the SCR catalyst washcoat is critically important to control the transient NOx spikes and ammonia slip.

PM Emission Control. A study by Corning and BASF examined the performance of different aftertreatment systems for natural gas (NG) engines in meeting the anticipated China VII emission standards, with a focus on the efficacy of particle filters for controlling PN10 emissions that originate from the lubricating oil [6738]. Several aftertreatment configurations—comprising close-coupled and underfloor three-way catalysts, as well as bare and coated filters—were tested on a 15 L China VI commercial NG engine. The study concluded that NG engines will likely require the integration of particle filters to comply with the future China VII PN10 limits. The results also revealed that NOx compliance was challenging and that fine-tuning of the lambda calibration will be essential for CNVII compliance.

In another study, Corning compared the PM filtration performance of different diesel particulate filter (DPF) materials intended for meeting the US EPA 2027 emission standards by light- and medium-duty trucks (8,501-14,000 lb) [6379]. Most of these LD/MD trucks are chassis-certified and their PM emissions are currently controlled to a level of 8-10 mg/mile. With the Tier 4 LD/MD vehicle emission standards, the PM limit is to be lowered to 0.5 mg/mile, phased-in from MY2027 to MY2031. While the new limit presents significant challenges for gasoline vehicles and will likely require the use of gasoline particulate filter (GPF), improved DPF technology may also be required for diesel vehicles. Three aluminum titanate (AT) filter materials of the same 45% porosity and 15 μm mean pore size were tested. The first unit was the current Tier 3 compliant filter, the second sample was the same material pre-loaded with ash, and the third sample was a new-generation material utilizing a surface porosity modification process originally developed for GPFs and commercialized under the trade name APT®. The results showed that the new-generation DPF could deliver high PM filtration efficiency along with other system level improvements.

Dumaray Automotive Italia (formerly GM Propulsion) presented their new diesel dosing unit (DDU) into the exhaust system for the thermal management of DPF regeneration [6735]. The new DDU operates at a 200 bar pressure, compared to 5 bar in the prior generation injector. The new high pressure unit provides better fuel atomization and eliminates the need for a mixer that was used with the old injector, resulting in a 10% reduction in exhaust gas pressure drop. A BSFC reduction of up to 1.5-2.0% was claimed with the new injector, due to reduced mixing and better efficiency of DPF regeneration.

Three-Way Catalysts. Researchers from the Institute of Science Tokyo measured on-road ammonia emissions from two light-duty gasoline vehicles with a conventional and a series-type hybrid powertrain, equipped with three-way catalysts [6736]. In the conventional gasoline vehicle, aggressive accelerations induced rapid fluctuations in engine speed, which led to NH3 emissions. In contrast, for the hybrid vehicle, NH3 emissions were primarily observed when the engine was started under specific conditions, while the driving behavior had only a minor impact on NH3. In both vehicles NH3 emissions were elevated during periods corresponding to CO emissions, which serve as precursors to NH3 formation.

Cummins developed a model for commercial natural gas three-way catalysts [6737]. The kinetic parameters were estimated based on experimental data, considering four groups of chemical reactions: NOx reduction; water gas shift reactions and steam reforming; the oxidation of HC, CO, and H2; and oxygen storage capacity (OSC) reactions.

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The next WCX SAE Congress is scheduled for April 27-29, 2027. After several decades at the Detroit Cobo Center/Huntington Place, the Congress venue will move to Novi, Michigan.

WCX technical sessions