Description

CM12 is a self-contained integrated multi-cylinder engine, dynamometer and instrumentation system. It is based on a 1.9 litre, 4-cylinder automotive diesel engine as used in Volkswagen cars. The Armfield CM12 can be run on a wide variety of biodiesel fuels and can be used for fuel testing and comparison exercises. (After each run on non-standard fuel, the engine should be run for a short time on a standard diesel fuel approved to EN590). An eddy current dynamometer provides a variable load on the engine, enabling the characteristic power and torque curves to be reproduced in the laboratory. The system comes complete with extensive instrumentation, including rpm measurement, torque (from which power can be calculated), plus various temperatures, pressures and flows (see Technical Specification). The whole system is designed to be linked to a computer using the software provided. This provides real time monitoring of the various sensors, with a wide range of data logging and graphical display options. The dynamometer and throttle can both be controlled electronically from the software, which makes installation into a closed test cell very straightforward and enables remote computer operation. A safety “watchdog” facility ensures the system shuts down safely in the event of computer failure or software lock-up. A further advantage of the computer control is that stable rpm readings can be easily achieved using the closed loop control function on the dynamometer drive. A closed loop primary water-cooling system is incorporated, complete with a heat exchanger for connecting into a secondary cold water supply.

Features / benefits

• 4-cylinder automotive engine
• Biodiesel compatible
• Plotting of characteristic torque and power curves against engine speed
• Full software control of system, including load and throttle settings
• Closed loop software control of brake loading to maintain constant engine speed during measurements
• Eddy current dynamometer to vary engine load 
• Secondary water cooling by heat exchanger, with measurement of temperature change and flow rate
• Engine manufacturer’s diagnostic software (displays fuel injection characteristics)
• Remote emergency stop and facility for safety interlocks
• Optional measurement of cylinder pressure and displaying this on a p-V diagram

Experimental Content

• Produce a set of performance curves for the engine under varying loads
• To determine the volumetric efficiency of the engine under varying loads
• To measure the pressure inside the cylinder during a complete cycle, and to relate this to the position of the piston, producing a PressureVolume diagram. (Requires CM12-12 Engine Indicator Set)
• To measure the fuel consumption of the engine