This content is not included in your SAE MOBILUS subscription, or you are not logged in.
Volumetric Efficiency Characteristics of a Crankcase-Supercharged 4-Stroke Cycle Engine with Rotary Disc Valves
ISSN: 0148-7191, e-ISSN: 2688-3627
Published February 01, 1990 by SAE International in United States
This content contains downloadable datasetsAnnotation ability available
In order to improve the volumetric efficiency of a crankcase-supercharged 4-stroke cycle engine in the high speed range, rotary disc valves were used at both the inlet and the outlet sides of the crankcase. The effects of the size of the opening and the phasing of the disc valves on volumetric efficiency were investigated and compared with a system using reed valves.
It was found that a volumetric efficiency higher than 120 % could be obtained over a speed of 3000-6000 rpm, which was not possible by using the reed valve system.
SUPERCHARGING SYSTEMS utilizing Roots type blowers and/or exhaust turbochargers have been used effectively for increasing the brake mean effective pressure of 4-stroke cycle engines. The authors built a prototype cranckcase-supercharged 4-stroke cycle engine, which used the underside of the piston as a supercharging pump, and confirmed the effectiveness of the concept by motoring and firing tests. Some of the results are reported in previous papers. (1)(2)* The previous system used reed valves at both the inlet and outlet of the crankcase and was found to be incapable of producing a high level of supercharging in the high engine speed range. The authors also reported that, in a Schnürle scavenged 2-stroke cycle engine using a rotary disc valve at the inlet port of the crankcase, it was possible to improve the delivery ratio and the torque characteristics over a wide engine speed range by changing the size of the opening (cut-angle) and the phasing (timing) of the rotary disc valve with engine speed. (3) Therefore, it was considered that, by replacing the reed valves in the crankcase-supercharged 4-stroke cycle engine with rotary disc valves, volumetric efficiency improvement in the high engine speed range might be achieved. Based on this concept, a crankcase-supercharged 4-stroke cycle engine with rotary disc valves at both the inlet and outlet ports of the crankcase was built, and its volumetric efficiency characteristics were investigated for different valve designs.
CitationOkanishi, N., Fukutani, I., and Watanabe, E., "Volumetric Efficiency Characteristics of a Crankcase-Supercharged 4-Stroke Cycle Engine with Rotary Disc Valves," SAE Technical Paper 900174, 1990, https://doi.org/10.4271/900174.
Data Sets - Support Documents
|Unnamed Dataset 1|
- Okanishi N. Fukutani I. Watanabe E. “Torque Boosting of 4-Stroke Cycle Spark-Ignition Engine in Low and Middle Engine Speed Ranges by Crankcase- Supercharging.” SAE Paper No. 840423 Detroit February 1984 SAE Trans. 93 1984 3·199
- Okanishi N. Fukutani I. Watanabe E. “Torque Boosting of 4-Stroke Cycle Engine.” Trans., JSAE 35 1987 60
- Okanishi N. Fukutani I. Watanabe E. “Torque Boosting of 2-Stroke Cycle Spark-Ignition Engine with Rotary Disc-Valve Inlet Port.” JSAE Technical Paper 862 1986 423
- Komotori K. Watanabe E. “A Study of the Delivery Ratio Characteristics of Crankcase-Scavenged Two-Stroke Cycle Engines.” SAE Paper No. 690136 Detroit January 1969 SAE Trans. 78 1969 608