Engine efficiency testing using percentage indicating voltmeter - for showing revolution rate drop when one cylinder is deactivated

摘要

The test device for a multiple cylinder combustion engine has a revolution rate sensor rotating synchronously with the crankshaft. It drives a controllable, esp. a monostable multivibrator, switch with a constant closed or open period charging a capacitor to a voltage corresp. to revolution rate for input to a digital voltmeter. It enables a direct percentage display of the drop in revolution rate following the isolation of one cylinder. This provides a direct efficiency reading without computation. A second digital voltmeter (10) has a bias voltage applied to one input connection (D). The other input (C) is driven by an operational amplifier (11) driven in parallel with the first voltmeter (5) and with a variable potential divider (R5,R6,R7) connected to its negative input. The bias voltage corresponds to -100.00 on the display.