10 February 2008
A QEM system has been applied to a V-twin engine in a John Deere utility vehicle. The system includes a two barrel throttle body with an injector for each cylinder, electronically mapped ignition and an electronic throttle control. The system has demonstrated excellent results in the following areas:
Starting
Engine starting has been enhanced by optimising fuel delivery and throttle settings against temperature and other parameters. In cold chamber testing the engine starts successfully at temperatures down to -30°C.
Idle control
By controlling of throttle position and ignition timing a refined idle was attained, which is mapped against engine temperature. The advantages are reduced idle speed with enhanced stability leading to lower fuel consumption and quieter engine running. See supporting images.
Driveability
The ability to control fuel flow, spark advance and throttle position within the QEM system, together with the monitoring of the throttle pedal and other engine parameters gave enhanced transient response and a smooth transition to the governed engine speed limit.
During closed throttle decelerations the fuel supply is shut off to give a further fuel saving advantage over a carburettor.
Full control of fuel metering, throttle position and ignition timing enables a QEM equipped vehicle to optimise its fuel consumption, throttle response and power output. Current and future emissions regulations can be met while at the same time offering engine protection parameters and enhanced driveability.
Summary
Applying the QEM system to a utility vehicle has resulted in a more refined vehicle with improved driveability and a measurable reduction in fuel consumption.