Method and apparatus for measuring engine compression ratio, clearance volume and related cylinder parameters
US4633707A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Aug 31, 1984 |
| Grant date | Jan 6, 1987 |
| Priority date | — |
| Expiry date | Aug 31, 2004 |
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. 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 determined using the constants .gamma. and k, and measured pressure at TDC or incremental volume figures. Compression ratio is 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. The invention is also implemented to determine cylinder leakage during the compression stroke, angles of operation of the intake and exhaust valves, effective compression ratio where the intake valve does not close at BDC, and/or cylin…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.