Method and apparatus for measuring engine compression ratio
US4505152A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 13, 1982 |
| Grant date | Mar 19, 1985 |
| Priority date | — |
| Expiry date | Sep 13, 2002 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01M15/08
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method and apparatus for measuring compression ratio and/or clearance volume in an internal combustion engine cylinder wherein the crankshaft angle associated with piston top dead center position is obtained and cylinder pressure is measured at a number of incrementally spaced piston positions, including the TDC position. Changes in cylinder volume between the incrementally spaced piston positions are determined from nominal engine design parameters. These multiple pressure and volume figures are then employed in a programmed microprocessor to determine the constants .gamma. and k in the polytropic equation for relating cylinder pressure to volume PV.sup..gamma. =k. Clearance volume V.sub.TDC is then determined using the constants .gamma. and k and the measured pressure at TDC. Compression ratio is then determined by the fraction (V.sub.DP +V.sub.TDC)/V.sub.TDC, where V.sub.DP is total piston displacement volume obtained from nominal engine design parameters.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.