Second control source for pump controller

[Richard L]

Pump speed system has a limited dynamic range and poor transient response. it is importnt to consider this before moving forward.

Dynamic range: A progressive delivery system should have at least a dynamic range of 10x to give good coverage on load and RPM. A PPS (Progressive pump speed) system will at best give you only 2x. A pressure change between 60psi to 240psi will only give you a dynamic range of 2x. A PWM valve system, will give you a dynamic range of 10x.

Transient response: This is very important, without the ability to alter flow quick during gear change and throttle modulation, A progressive system is a tuning nightmware. PPS system cannot alter pump's rotational speed quickly to match the load and RPM change due to inertia. PWM valve, as used on modern fuel injection system, can response within a few milli-seconds.