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Engine systems
Published in Tom Denton, Automobile Mechanical and Electrical Systems, 2018
The purpose of cylinder deactivation technology is to reduce fuel consumption on petrol/gasoline engines. Large capacity engines were renowned for poor fuel consumption under low speed and torque conditions. This inefficiency is known as pumping loss and is used to describe a situation where an engine that is unable to draw in a sufficient quantity of air and fuel mixture on the inlet stroke, to produce high cylinder pressure during compression.
New Technologies, Vehicle Features, and Technology Development Plan
Published in Vivek D. Bhise, Automotive Product Development, 2017
The disadvantages of direct injection are its cost and complexity. Because the injector tips are mounted right into the combustion chamber, the materials in the injector have to withstand both high temperatures and high pressures, and thus, they are more expensive. Also, the high pressure needed to inject fuel directly into the cylinders means that more expensive high-pressure fuel pumps are required. These are typically mechanically driven from the engine, and thus, they increase the engine complexity.3.Cylinder deactivation: This method involves deactivation of some cylinders (typically two to four cylinders in six- to eight-cylinder vehicles) when the vehicle is cruising at constant speed and the demand for power is lower than when the vehicle is accelerating. Under light driving load conditions, cylinder deactivation will reduce pumping losses from deactivated cylinders and thus improve fuel economy.4.Stop/start: The stop/start method involves stopping the internal combustion engine when the vehicle comes to a full stop and restarting it immediately when the driver presses the gas pedal to accelerate the vehicle. The system requires a larger starter motor and battery capacity to handle frequent stop/start cycles. The stop/start method can reduce energy consumption in city traffic conditions where the vehicle makes frequent stops in traffic and at intersections.5.Alternate fuel sources: To reduce demand for gasoline, engines using a number of alternative fuel sources have been developed. These include (a) natural gas (compressed natural gas [CNG] and liquefied natural gas [LNG]), (b) diesel (e.g., turbo-diesel), (c) biomass fuels, and (d) hydrogen (i.e., hydrogen-powered fuel cell vehicles).
Connected and automated road vehicles: state of the art and future challenges
Published in Vehicle System Dynamics, 2020
Tulga Ersal, Ilya Kolmanovsky, Neda Masoud, Necmiye Ozay, Jeffrey Scruggs, Ram Vasudevan, Gábor Orosz
We also note that the engine torque is a function of engine control inputs (fueling rate, air-to-fuel ratio, spark timing, valve timing, residual gas fraction, cylinder deactivation, etc.) and engine dynamics (e.g. manifold filling dynamics, turbocharger dynamics, etc.); see [76] for details. For the powertrains of electric vehicles or hybrid electric vehicles, the battery dynamics, the efficiency characteristics of motor-generators and planetary transmission, and regenerative braking need to be taken into account.
Trends in onroad transportation energy and emissions
Published in Journal of the Air & Waste Management Association, 2018
Some other technology trends include variable valve timing (VVT), cylinder deactivation for lower power demand driving situations, fuel cutoff during deceleration, and engine stop–start during deceleration and idle (EPA 2016e; NRC 2015). Stop–start reduces fuel use only during operational conditions when fuel consumption is typically already low. The reduction in fuel consumption for individual measures such as these ranges from approximately 0.4% to 2.5% (NRC 2015).