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Cylinder deactivation (CDA) is an effective method to adjust the engine displacement for maximum output and improve fuel economy by adjusting the number of active cylinders in combustion engines. A Switching Roller Finger Follower (SRFF) is an economic solution for CDA that minimizes changes and preserves the overall width, height, or length of Dual Overhead Cam (DOHC) engines. The CDA SRFF provides the flexibility of either transferring or suppressing the camshaft movement to the valves influencing the engine performance and fuel economy by reducing the pumping losses. This paper addresses the performance and durability of the CDA SRFF system to meet the reliability for gasoline passenger car engines. Extensive tests were conducted to demonstrate the dynamic stability at high engine speeds and the system capacity of switching between high and low engine displacement within one camshaft revolution.

Commercial vehicles are moving in the direction of improving brake thermal efficiency while also meeting future diesel emission requirements. This study is focused on improving efficiency by replacing the variable geometry turbine (VGT) turbocharger with a high-efficiency fixed geometry turbocharger. Engine-out (EO) NOX emissions are maintained by providing the required amount of exhaust gas recirculation (EGR) using a 48 V motor driven EGR pump downstream of the EGR cooler. This engine is also equipped with cylinder deactivation (CDA) hardware such that the engine can be optimized at low load operation using the combination of the high-efficiency turbocharger, EGR pump and CDA. The exhaust aftertreatment system has been shown to meet 2027 emissions using the baseline engine hardware as it includes a close coupled light-off SCR followed by a downstream SCR system.

Commercial vehicles require fast aftertreatment heat up in order to move the selective catalyst reduction (SCR) into the most efficient temperature range to meet upcoming NOx regulations. Heavy duty cylinder deactivation (CDA) is an important technology to meet these regulations. One of the challenges with implementing CDA in the heavy-duty market is to ensure acceptable engine and vehicle vibration. The purpose of this paper is to mitigate CDA vibration on a vehicle to acceptable levels. Emphasis was placed at the idle operating condition. Idle is the most challenging operating mode to enable, as deactivating cylinders reduces the frequency of the forcing function due to engine firing, which leads to a need to isolate these lower frequencies. A focused modal analysis of the engine (source), frame (path), and cabin (path/receiver) was used to characterize the vehicle system.

Commercial vehicle powertrain is called to respect a challenging roadmap for CO2 emissions reduction, quite complex to achieve just improving technologies currently on the market. In this perspective alternative solutions are gaining interest, and the use of green H2 as fuel for ICE is considered a high potential solution with fast and easy adoption. NOx emission is still a problem for H2 ICE and can be managed operating the engine with lean air fuel ratio all over the engine map. This combustion strategy will challenge the boosting system as lean H2 combustion will require quite higher air flow compared to diesel for the same power density in steady state. Similar problem will show up in transient response particularly when acceleration starts from low load and the exhaust gases enthalpy is very poor and insufficient to spin the turbine. The analysis presented in this paper will show and quantify the positive impact that a supercharger has on both the above mentions problems.