Topic
Small engine
About: Small engine is a research topic. Over the lifetime, 207 publications have been published within this topic receiving 1419 citations.
Papers published on a yearly basis
Papers
TL;DR: In this paper, the benefits of engine downsizing and turbocharging and the possible mechanisms of these effects are analyzed. But, the authors focus on a small engine and do not consider the performance of a large engine.
Abstract: Data on several hundred family sedan production vehicles over a ten-year period are analyzed to compare turbocharged with non-turbocharged engines. It is shown that for the same power turbocharging enables gasoline engine downsizing by about 30%, improves fuel economy by 8-10% while improving torque and acceleration performance. Data with experimental turbocharged, downsized gasoline engines also shows that in the same vehicle, for the same power and performance, downsized turbocharged engines can give about 18% improvement in fuel economy. The paper discusses these data and analyzes the benefits of engine downsizing and turbocharging and the possible mechanisms of these effects. It is shown that the same basic small engine can be turbocharged using a wide range of turbocharger matching to cover a power range normally covered by 4-5 engine families of progressively increasing displacement. Thus additional benefits can be obtained by rationalizing the engine product lines. Advanced turbocharging technology for gasoline engines is discussed including cold start emissions (catalyst light-off), high temperature materials, variable geometry mechanisms and electrically assisted turbocharging. It is shown that these technologies combined with an appropriate control logic can yield great benefits in driveability while at the same time giving all the fuel economy, weight and packaging benefits of engine downsizing.
163 citations
Patent•
26 Nov 1997
TL;DR: In this paper, a 6-point Fourier Transform (FFT) is calculated continuously to provide imbalance detection of an unbalanced engine, which results in nonzero magnitudes of the FFT components that correspond to the 0.5, 1.0, and 1.5 engine orders.
Abstract: Manufacturing/design imperfections and component failures in the fuel system/engine can lead to non-uniform torque production among the cylinders. Non-uniform cylinder torques can be observed as small engine speed fluctuations about the average engine speed at any given operating point. Severe imbalance conditions can be heard, felt, and seen by human operators. The present invention uses the fluctuations in engine speed to detect an unbalanced engine and attempts to correct the unbalance by applying trims to the fueling commands for each individual cylinder. The present invention is based on the calculation of a 6-point Fourier Transform (FFT) of engine speed data over one complete engine cycle. This FFT is calculated continuously to provide imbalance detection. An unbalanced engine results in non-zero magnitudes of the FFT components that correspond to the 0.5, 1.0, and 1.5 engine orders. The compensation scheme of the present invention uses iteration to drive the magnitudes of these components to zero if the engine is detected to be unbalanced.
67 citations
Patent•
18 Sep 1992TL;DR: In this article, a stepper motor is used to control the air/fuel ratio input to a small engine, and a fault detector circuit stops the engine if the sensed oxygen level is outside a preset range for more than a preset time interval.
Abstract: A system for controlling the air/fuel ratio input to a small engine measures the oxygen level in the engine's exhaust and compares it with a reference level. A stepper motor controls the air/fuel ratio and it is advanced one step each time a clock pulse is produced in a direction determined by the level of exhaust oxygen. A fault detector circuit stops the engine if the sensed oxygen level is outside a preset range for more than a preset time interval.
60 citations
Patent•
2 Mar 2001
TL;DR: In this paper, the instantaneous engine speed data is filtered by discrete second-order band-pass filters to find the engine speed fluctuations at particular frequencies, and the output of the filters is identical to power spectral density of speed signal at those frequencies.
Abstract: Manufacturing imperfections and component failures in the fuel system of an engine, can lead to non-uniform torque production among the cylinders. Non-uniform cylinder torques can be observed as small engine speed fluctuations about the average engine speed at any given operating point. Engine speed data contains fluctuations at different frequencies. The amplitude of fluctuations at some known frequencies tell about the health of the fuel injectors and the engine. In the present invention, the instantaneous engine speed data is filtered by discrete second-order band-pass filters to find the engine speed fluctuations at particular frequencies. The output of the filters is identical to power spectral density of speed signal at those frequencies. The amplitude of each filter output is then compared to a predetermined threshold value. If the amplitude is bigger than this threshold, it indicates the existence of low fueling or high fueling fuel injectors. If the amplitude is bigger than a second higher threshold, it indicates the existence of dead fuel injectors.
54 citations
TL;DR: In this article, an exhaust energy recovery system for a heavily downsized gasoline engine is presented. But the authors focus on the design of a high performance low pressure turbine to recover latent energy left in the exhaust gas after expanding in the main turbocharger turbine.
53 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2021 | 3 |
| 2020 | 7 |
| 2019 | 8 |
| 2018 | 5 |
| 2017 | 9 |
| 2016 | 7 |