Single cylinder engine transient test system

2006 ◽  
Vol 40 (1/2/3) ◽  
pp. 196 ◽  
Author(s):  
John J. Moskwa ◽  
John L. Lahti ◽  
Matthew W. Snyder
Author(s):  
John L. Lahti ◽  
Matthew W. Snyder ◽  
John J. Moskwa

A transient test system was developed for a single cylinder research engine that greatly improves test accuracy by allowing the single cylinder to operate as though it were part of a multi-cylinder engine. The system contains two unique test components: a high bandwidth transient hydrostatic dynamometer, and an intake airflow simulator. The high bandwidth dynamometer is used to produce a speed trajectory for the single cylinder engine that is equivalent to that produced by a multi-cylinder engine. The dynamometer has high torque capacity and low inertia allowing it to simulate the speed ripple of a multi-cylinder engine while the single cylinder engine is firing. Hardware in loop models of the drivetrain and other components can be used to test the engine as though it were part of a complete vehicle, allowing standardized emissions tests to be run. The intake airflow simulator is a specialized intake manifold that uses solenoid air valves and a vacuum pump to draw air from the manifold plenum in a manner that simulates flow to other engine cylinders, which are not present in the single cylinder test configuration. By regulating this flow from the intake manifold, the pressure in the manifold and the flow through the induction system are nearly identical to that of the multi-cylinder application. The intake airflow simulator allows the intake runner wave dynamics to be more representative of the intended multi-cylinder application because the appropriate pressure trajectory is maintained in the intake manifold plenum throughout the engine cycle. The system is ideally suited for engine control development because an actual engine cylinder is used along with a test system capable of generating a wide range of transient test conditions. The ability to perform transient tests with a single cylinder engine may open up new areas of research exploring combustion and flow under transient conditions. The system can also be used for testing the engine under conditions such as cylinder deactivation, fuel cut-off, and engine restart. The improved rotational dynamics and improved intake manifold dynamics of the test system allow the single cylinder engine to be used for control development and emissions testing early in the engine development process. This can reduce development time and cost because it allows hardware problems to be identified before building more expensive multi-cylinder engines.


Author(s):  
John L. Lahti ◽  
Steven J. Andrasko ◽  
John J. Moskwa

A new high-bandwidth transient hydrostatic dynamometer test system has been developed that accurately replicates multi-cylinder engine operation using a single-cylinder research engine. Single-cylinder engines are typically used for research because of their low cost and good cylinder accessibility for instrumentation and optics. This dynamometer maintains these advantages while dramatically improving transient and low speed testing capabilities. The system also incorporates hardware-in-the-loop models for simulation of other components that would typically be present in a vehicle application. These models include: adjoining cylinders and ancillary components in the engine, the transmission, driveline, and vehicle load. Utilizing these models it is possible to replicate actual driving cycles. This high-bandwidth transient dynamometer extends the test capabilities of single-cylinder research far beyond the traditional steady state regime, enabling transient speed single-cylinder engine research while providing single-cylinder engine operation that is comparable to the multi-cylinder engine.


Author(s):  
John J. Moskwa ◽  
Mark B. Murphy

Single-cylinder test engines are used extensively in engine research, and sparingly in engine development, as an inexpensive way to test or evaluate new concepts or to understand in-cylinder motion or combustion. They also allow good access to the cylinder for instrumentation, however, these single-cylinder engines differ significantly in rotational dynamics, gas intake dynamics, heat transfer dynamics, dynamic coupling between cylinders, and in other areas. Charge motion within the cylinder, even during the closed period differs from the multi-cylinder engine because of the differences in both instantaneous flow and momentum. Researchers in the Powertrain Control Research Laboratory (PCRL) at the University of Wisconsin-Madison have developed single-cylinder engine transient test systems that control the instantaneous dynamic cylinder boundary conditions to replicate those in the target multi-cylinder engine. The overall goal is to exploit the benefits of the single-cylinder engine, while eliminating the negative aspects of this device, and to have the single-cylinder “think” it is dynamically operating within a multi-cylinder engine. This paper describes the latest developments in controlling the intake gas dynamics of the single-cylinder engine to meet these goals. A combination of both rotary and proportional valves are used to accurately replicate the instantaneous intake airflow that exists in the multi-cylinder engine, including during transients. A Fourier-based approach instead of the previous time-based trajectory control is used to accomplish these goals. This is a third generation of intake air simulator (IAS3) that is a significant step forward in both simplifying the system, and in significantly expanding the operating envelop of the engine to include the full engine operating range of the multi-cylinder engine. A brief introduction of the entire transient test system will show the reader how rotational, heat transfer, and gas dynamics are controlled, and how the IAS3 fits into this overall system.


Author(s):  
Derek A. Mangun ◽  
John J. Moskwa

Researchers in the Powertrain Control Research Laboratory (PCRL) at the University of Wisconsin-Madison have developed and built a single-cylinder engine transient test system which accurately replicates the dynamic operation of a multi-cylinder engine. Using hardware-in-the-loop (HIL) simulation, the multi-cylinder engine’s transient (a) rotational dynamics, (b) intake gas dynamics, and (c) heat transfer dynamics are reproduced in real time using several patented subsystem designs. These subsystems produce the dynamic boundary conditions that would be present for a given cylinder within a multi-cylinder engine, based on either real-time model execution or predetermined command trajectories (e.g. measured data). In addition to replicating the effects of the virtual cylinders, the test system facilitates extension of the single-cylinder engine capabilities beyond typical steady-state regime limitations. The primary goals of this project are to retain the attributes of the single-cylinder engine that are most beneficial while overcoming the problems which cause the single-cylinder engine to operate differently than a multi-cylinder engine. This system represents a very unique test bed for controlling and understanding the influences of changes in the engine design and control, solves several of the problems associated with the operation of a single-cylinder engine, and allows rapid transient testing with slew rates in excess of 10,000 rpm/s. A virtual powertrain and vehicle model can be incorporated into this system so that standardized vehicle emission testing can be conducted with this single-cylinder engine system (e.g., FTP and other transient drive cycle tests). This paper reports the research findings of the performance effects achieved by including the multi-cylinder dynamic interactions during HIL simulation using only single-cylinder engine hardware. The target engine used for this study is the Ford 3.0 L V-6 SI engine, and both the multi- and single-cylinder engines are resident in the PCRL. By directly comparing the operation of this virtual multi-cylinder transient test system with its actual multi-cylinder engine counterpart, the influences of the included dynamics are documented. Evaluations include comparative data from rotational dynamics and intake gas dynamics, as well as the ability to control heat transfer dynamics and conduct exhaust emission testing.


2004 ◽  
Author(s):  
Michael McMillian ◽  
Steven Richardson ◽  
Steven D. Woodruff ◽  
Dustin McIntyre

2021 ◽  
pp. 1-39
Author(s):  
Akash Chandrabhan Chandekar ◽  
Sushmita Deka ◽  
Biplab K. Debnath ◽  
Ramesh Babu Pallekonda

Abstract The persistent efforts among the researchers are being done to reduce emissions by the exploration of different alternative fuels. The application of alternative fuel is also found to influence engine vibration. The present study explores the potential connection between the change of the engine operating parameters and the engine vibration pattern. The objective is to analyse the effect of alternative fuel on engine vibration and performance. The experiments are performed on two different engines of single cylinder and twin-cylinder variants at the load range of 0 to 34Nm, with steps of 6.8Nm and at the constant speed of 1500rpm. The single cylinder engine, fuelled with only diesel mode, is tested at two compression ratios of 16.5 and 17.5. While, the twin-cylinder engine with a constant compression ratio of 16.5, is tested at both diesel unifuel and diesel-compressed natural gas dual-fuel modes. Further, in dual-fuel mode, tests are conducted with compressed natural gas substitutions of 40%, 60% and 80% for given loads and speed. The engine vibration signatures are measured in terms of root mean square acceleration, representing the amplitude of vibration. The combustion parameters considered are cylinder pressure, rate of pressure rise, heat release rate and ignition delay. At higher loads, the vibration amplitude increases along with the cylinder pressure. The maximum peak cylinder pressure of 95bar is found in the case of the single cylinder engine at the highest load condition that also produced a peak vibration of 3219m/s2.


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