Torque Of Diesel Engine Research Articles

Study on Through-Flow Characteristics of a Diesel Two-Stage Supercharged Centrifugal Compressor under Variable-Altitude and Multiple Operating Conditions

Understanding the influence of environmental boundary parameters on the through-flow characteristics of two-stage supercharged centrifugal compressors is the key to maximizing the power recovery potential of diesel engines at high altitudes. In this paper, the influence of the compressor through-flow characteristics on the full-load thermal cycle performance of a diesel engine under variable altitude is studied by means of tests and simulation. The results show that with the increase in altitude, the range of stable work flow decreases, and the pressure ratio of the plugging point changes greatly with altitude. The efficiency of the compressor with the same mass flow point decreases, and the highest efficiency point moves in the direction of the small flow range. With the goal of maximizing the torque of the diesel engine under full load and low speed, the key geometric parameters of the variable-altitude through-flow characteristics of the two-stage supercharged compressor were optimized as follows: at the altitudes of 0 m, 2500 m, and 5500 m, the diesel engine torque increased by 5.89%, 3.78%, and 2.18%, respectively. Based on the optimization method of the compressor through-flow design, a new direction is provided to break through the research on the independent limitation of the diesel engine thermal cycle performance optimization and compressor flow control.

Torsional vibration analysis of diesel driven propulsion systems: The case of a polar-class vessel

The reliability of marine propulsion plants of ice-going vessels is essential in preserving ship safety during ice navigation. Therefore, the development of reliable design tools of the transmission shafting systems is fundamental to simulate ice–propeller interaction processes correctly. This paper outlines a methodology to model the torsional dynamics of fully-geared, Diesel-driven propulsion systems; specifically, a novel analytical model to simulate the dynamic Diesel engine torque is described. We consider the Canadian Coast Guard heavy icebreaker Terry Fox as a case study, whose propulsion plant includes two shaftlines driven by two 4-stroke Diesel engines each and equipped with controllable pitch propellers (CPP). On this vessel, we performed full-scale measurements during open-water sea trials to: (i) validate the Diesel-drive mathematical model; (ii) update the numerical eigenfrequencies of the system; (iii) determine the curve of the propeller-absorbed hydrodynamic torque. Finally, we simulate the dynamic response of the shaftline’s model by applying an ice–propeller transient excitation. The results indicate the effectiveness of the proposed methodology to simulate the Diesel engine torque, and the significance of considering the CPP pitch variation in transient-state conditions when ice-induced loads are concerned.

FEATURES OF REPRESENTING THE TORQUE OF A DIESEL ENGINE AS AN INDEPENDENT FACTOR OF INFLUENCE ON ITS STARTING QUALITIES

In this study, we presented an original method for a high-speed small displacement diesel engine (HSSDDE) start with changing the minimum cold start temperature without using a climate chamber. This work deals with the diesel engine torque reduced to the crankshaft while its electric starter motoring in the cold start process. The characteristic, numerical values and influence of the average torque factor and its diesel engine start process efficiency are given. Scheme of the laboratory bench intended for study of the HSSDDE starting qualities in the conditions of a higher education institution is presented. The structure of the information-measuring system for determining the parameters, used in current study, is given. Empirically shown, that the equivalent cold start temperature can be presented as a dependent factor of the adjustable diesel engine torque during cold start. 4DTNA series HSSDDE empirical dependencies coefficients are determined. The torque of crankshaft motoring was determined with the classical method of a calibrated starter using the correlation of electric starter shaft torque while motoring the crankshaft with the diesel engine torque. Some standard motor oils viscosity-temperature characteristics regression dependences in the range of starting temperatures and the empirical torque dependence on the oil kinematic viscosity are determined. As a result, a table of equivalent cold start temperatures was created using variable loads during HSSDDE startup. On the basis of the results of the experiment the theoretically calculated values of equivalent cold start temperatures for other oils used in the operation of HSSDDE are given. Specified range of variation of the cold start equivalent temperature factor for further polyfactorial investigation of the HSSDDE start process, which will take values of 0 °C, 5 °C and 10 °C.

Parallel Control for Hybrid Propulsion of Multifunction Ships

Multifunction ships, naval vessels in particular, need to reduce fuel consumption while maintaining manoeuvrability. Hybrid propulsion that runs a main diesel engine and electric drive in parallel can achieve this. However, a parallel control strategy needs to be developed. In this paper, we use a simulation model of a hybrid propulsion system to investigate two parallel control strategies for diesel mechanical and electrical propulsion on multifunction ships. For the case study frigate, parallel control can increase the ship top speed with 3 kts when using two 4 MW electric drives and two 10 MW main diesel engines, compared with the same baseline hybrid propulsion without parallel control. The diesel engine speed control with electric drive torque control strategy increases ship acceleration rate with 17% and reduces average engine thermal loading with 150 K. Moreover, the electric drive speed control with diesel engine torque control strategy can improve acceleration rate by 40%, while eliminating thermal loading fluctuation due to heavy seas, and also reducing engine average thermal loading with 150 K. Future combination of the proposed electric drive speed control strategy with an adaptive pitch control and optimal power split strategy can potentially further increase hybrid propulsion plant performance.

Performance Analysis of the Vehicle Diesel Engine-ORC Combined System Based on a Screw Expander

To achieve energy saving and emission reduction for vehicle diesel engines, the organic Rankine cycle (ORC) was employed to recover waste heat from vehicle diesel engines, R245fa was used as ORC working fluid, and the resulting vehicle diesel engine-ORC combined system was presented. The variation law of engine exhaust energy rate under various operating conditions was obtained, and the running performances of the screw expander were introduced. Based on thermodynamic models and theoretical calculations, the running performance of the vehicle diesel engine-ORC combined system was analyzed under various engine operating condition scenarios. Four evaluation indexes were defined: engine thermal efficiency increasing ratio (ETEIR), waste heat recovery efficiency (WHRE), brake specific fuel consumption (BSFC) of the combined system, and improvement ratio of BSFC (IRBSFC). Results showed that when the diesel engine speed is 2200 r/min and diesel engine torque is 1200 N·m, the power output of the combined system reaches its maximum of approximately 308.6 kW, which is 28.6 kW higher than that of the diesel engine. ETEIR, WHRE, and IRBSFC all reach their maxima at 10.25%, 9.90%, and 9.30%, respectively. Compared with that of the diesel engine, the BSFC of the combined system is obviously improved under various engine operating conditions.

Impacts of Continuously Regenerating Trap Technology on the Regulated Gas Emissions for a China-V Diesel Engine

In this paper, the effects of continuously regenerating trap (CRT) after-treatment system on performance, fuel efficiency and regulated gas emissions from a turbocharged electronically controlled high pressure common rail diesel engine that meets China-V regulation have been investigated. The test results revealed that: the power and torque of diesel engine after the installation of CRT after-treatment system declines slightly, which is limited to 2%, and the rise in brake specific fuel consumption is around 2%. At the same time, the emission of CO decreased significantly by 86% to 94%, NOx also reduced slightly by 8% to 12%. However, the emission of HC dropped at part loads and rose at full load modes since the original engine emission is already quite low.

Diesel engine torque ripple reduction through LPV control in hybrid electric vehicle powertrain: Experimental results

This paper presents a case of persistent harmonic active control for an HEV (Hybrid Electric Vehicle) powertrain. The active control is adapted for a hybrid powertrain consisting of a one-cylinder diesel engine, coupled with a PMSM (Permanent Magnet Synchronous Machine). The PMSM assures the propulsion of the vehicle, as in conventional mild-hybrid electrical vehicles. In addition, it provides speed ripple reductions of the diesel engine. Due to the HEV speed variation, the active control must match this variation. The speed is introduced as a parameter in order to devise an LPV (linear parameter varying) control strategy. The suitability of LPV control for engine torque ripple reduction is demonstrated through a torque control implementation of the PMSM. The control strategy uses the internal model principle of multi-sinusoidal persistent disturbances. The controller is designed to involve several steps, including LMI-based (Linear Matrix Inequalities) optimization. The results show that, for the first and second orders of the ripple, speed oscillations can be reduced when the speed varies. An industrial test bed is used to validate the effectiveness of the approach and the power consumption of the strategy is analyzed.

Brake Valve Timing and Fuel Injection: a Unified Engine Torque Actuator for Heavy-Duty Vehicles

A unified engine torque actuator for heavy-duty vehicles is developed in this paper. Based on averaging and identification of the instantaneous torque response for changes in brake valve timing and fuel flow, we derive a control oriented engine model of a six cylinder, 350 Hp turbocharged diesel engine, equipped with a compression brake. This work bridges the gap between the detailed compression crank angle based models developed in the engine design community, and the first order lag representation of diesel engine torque response used in the vehicle dynamics community. Moreover, we integrate the compression brake actuator with the service brakes and design a PI-controller that emulates the driver's actions during long descends on grades. The controller simply uses the engine speed measurement to activate the service brakes only when needed.