Topic
Variable valve timing
About: Variable valve timing is a research topic. Over the lifetime, 2111 publications have been published within this topic receiving 18221 citations. The topic is also known as: VVT.
Papers published on a yearly basis
1 / 2
Papers
TL;DR: In this article, the authors investigated the performance, emission and combustion characteristics of low temperature combustion (LTC) mode engines and provided a perspective plan to the researchers for enhancing the performance and emission behavior of an engine by using LTC mode with lower NOx and soot emissions.
Abstract: Low temperature combustion (LTC) is a recent engine technology that can reduce the oxides of nitrogen (NOx) and soot emissions simultaneously while maintaining higher thermal efficiency. The present review work investigates the performance, emission and combustion characteristics of LTC mode engines. Partially premixed LTC (PPLTC), homogeneous charge compression ignition (HCCI), premixed charge compression ignition (PCCI) and reactivity controlled compression ignition (RCCI) modes are researched under LTC mode. In recent decades, different engine strategies have been employed to reduce exhaust emissions and to enhance thermal efficiency. Exhaust gas recirculation, variable valve timing (VVT), advanced fuel injection technologies are adapted to achieve LTC mode in internal combustion (IC) engines to get improved outcomes. This review highlights the properties of fuels, fuel supply systems, valve actuation mechanisms, engine operating conditions and its effects on the engine characteristics. This review provides a perspective plan to the researchers for enhancing the performance, emission and combustion behavior of an engine by using LTC mode with lower NOx and soot emissions. Among LTC mode engines, RCCI mode engine operates well in 60% load, 60% premixed ratio, 35:1 air-fuel ratio and 56% brake thermal efficiency within the combustion phasing control.
233 citations
TL;DR: In this paper, the potential of a simple variable valve timing (VVT) system has been investigated and a numerical approach, based on both 1-D and 3-D computational models, has been adopted in order to evaluate the engine performance when load is controlled by the VVT system and to deeply investigate the influence, on in-cylinder phenomena, of the valve timing variation.
193 citations
Patent•
6 Apr 2006
TL;DR: In this article, a variable valve timing mechanism driven by engine oil and controlled by an electronic control device forcefully drives the working angle variable mechanism so as to remove foreign matters adhered/deposited due to deterioration of engine oil.
Abstract: PROBLEM TO BE SOLVED: To provide a control device of an internal combustion engine which can be subjected to treatment for returning a working angle variable mechanism to a normal state before deterioration of a fixing state by grasping a fixing state of a working angle variable mechanism caused by a deterioration of engine oil from the early stage. SOLUTION: An engine is equipped with a variable valve timing mechanism driven by engine oil and controlled so as to make an actual valve timing of an intake valve a target valve timing of the intake valve corresponding to an engine operating condition, and a working angle variable mechanism which changes a working angle of the intake cam associated with valve opening of the intake valve and in which the engine oil is employed for the lubrication of a movable part. When a deviation ΔV between the change rate Vtrg of target valve timing and the change rate Vact of actual valve timing in the variable valve timing mechanism is more than a prescribed value α an electronic control device forcefully drives the working angle variable mechanism (Step 500) so as to remove foreign matters adhered/deposited due to deterioration of engine oil. COPYRIGHT: (C)2006,JPO&NCIPI
189 citations
TL;DR: In this paper, artificial neural networks (ANNs) were used to determine the effects of intake valve timing on the engine performance and fuel economy, which can be used for the prediction of engine performance as an appropriate method for spark-ignition engines.
136 citations
Patent•
3 Apr 1997TL;DR: A variable valve timing mechanism of an internal combustion engine varies the valve timing by varying the rotation phase of the camshaft with respect to a reference rotation phase on the drive shaft of the engine.
Abstract: A variable valve timing mechanism of an internal combustion engine varies the valve timing by varying the rotation phase of the camshaft with respect to a reference rotation phase of the drive shaft of the engine The mechanism has a first rotation member and a second rotation member The first rotation member rotates in fixed synchronism with the drive shaft and has at least one recess therein The second rotation member is located within the first rotation member and rotates integrally with the camshaft The second rotation member has a vane within the recess The vane is movable between two walls of the recess and divides the recess into first and second pressure chambers Hydraulic fluid pressure causes relative rotation of the second rotation member with respect to the first rotation member by applying pressure to the first and second pressure chambers to move the vane The mechanism further has a lock device The lock device restricts the relative rotation of the second rotation member with respect to the first rotation member such that the vane is kept between the two recess walls when the engine is cranking The lock device is released after the engine reaches a predetermined running condition
134 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2022 | 3 |
| 2021 | 16 |
| 2020 | 33 |
| 2019 | 42 |
| 2018 | 48 |
| 2017 | 46 |