Simple TA based FreeEMS for Sean's LT1
Posted: Thu Apr 21, 2011 8:19 pm
In lieu of proper documents showing options and configurations and fixes for the Spin 1 Puma boards that Sean has in his cardboard box, and the fact that even if they magically appeared right now, it'd be too late to order parts, perform mods, and assemble them, we're going to run his car from a TA board with some aux circuits.
This thread is to document what we do, for our selves, and for others who want to attempt this.
Inputs:
Sean uses a partial OEM ecu to control the fuel pump and condition the inputs. The only two inputs that are not 0-5v are the IAT and CHT sensors. These require a bias circuit and some filtering. 2.x resistor for bias, 1.6k for current limit to cpu, some caps configured around these to provide a smooth signal. The puma setup is fine, as are OEM circuits, copy at will.
Outputs:
The OEM ECU is handling the fuel pump control for us.
Sean uses an LTCC e-dizzy unit with a 12k input impedance, so a simple 5v output is all that is required to hit the coils on his car. This is best provided by an XOR chip such that we can configure it up or down as required at a later date.
Sean's intention is to run each injector from a single protected logic FET, we'll order 8 of those (or more for spares) and the likely candidate is the vnp10n07 part which powered the volvo injectors, and the 4age injectors. Experience has taught us that these are not driven properly from the CPU port on a 1:1 basis, let alone on the 2:1 basis that we need to use for this iteration of the build. Instead of that, the FETs will be driven with low value current limit resistors and a line driver chip with the CPU driving two channels of the line driver from one pin through 1.6k resistors.
Shopping list:
1 x DIP8 XOR, part number: 74HC86
2 x DIP8 Buffer, part number: 74HC367
8 x Protected Logic FET, part number: VNP10N07
2 x 1/4w 1% OR BETTER accurate bias resistors of chosen value to suit GM sensors (2.2k, 2.4k, 2.7k are suitable)
N x small ceramic caps for filtering inputs 0.1uF & 0.01uF
16+ x 1.6k 1% 1/4w resistors (cpu to/from world)
10+ x 10ohm 1% 1/4w resistors (options for current limits)
10+ x 100ohm 1% 1/4w resistors (options for current limits)
10+ x 330ohm 1% 1/4w resistors (options for current limits)
10+ x 1k 1% 1/4w resistors (options for current limits)
10+ x 10k 1% 1/4w resistors (weak pull down option)
Clearly various caps and resistors are optional, the first 4 items are necessary, though, at the very least.
Fred.
This thread is to document what we do, for our selves, and for others who want to attempt this.
Inputs:
Sean uses a partial OEM ecu to control the fuel pump and condition the inputs. The only two inputs that are not 0-5v are the IAT and CHT sensors. These require a bias circuit and some filtering. 2.x resistor for bias, 1.6k for current limit to cpu, some caps configured around these to provide a smooth signal. The puma setup is fine, as are OEM circuits, copy at will.
Outputs:
The OEM ECU is handling the fuel pump control for us.
Sean uses an LTCC e-dizzy unit with a 12k input impedance, so a simple 5v output is all that is required to hit the coils on his car. This is best provided by an XOR chip such that we can configure it up or down as required at a later date.
Sean's intention is to run each injector from a single protected logic FET, we'll order 8 of those (or more for spares) and the likely candidate is the vnp10n07 part which powered the volvo injectors, and the 4age injectors. Experience has taught us that these are not driven properly from the CPU port on a 1:1 basis, let alone on the 2:1 basis that we need to use for this iteration of the build. Instead of that, the FETs will be driven with low value current limit resistors and a line driver chip with the CPU driving two channels of the line driver from one pin through 1.6k resistors.
Shopping list:
1 x DIP8 XOR, part number: 74HC86
2 x DIP8 Buffer, part number: 74HC367
8 x Protected Logic FET, part number: VNP10N07
2 x 1/4w 1% OR BETTER accurate bias resistors of chosen value to suit GM sensors (2.2k, 2.4k, 2.7k are suitable)
N x small ceramic caps for filtering inputs 0.1uF & 0.01uF
16+ x 1.6k 1% 1/4w resistors (cpu to/from world)
10+ x 10ohm 1% 1/4w resistors (options for current limits)
10+ x 100ohm 1% 1/4w resistors (options for current limits)
10+ x 330ohm 1% 1/4w resistors (options for current limits)
10+ x 1k 1% 1/4w resistors (options for current limits)
10+ x 10k 1% 1/4w resistors (weak pull down option)
Clearly various caps and resistors are optional, the first 4 items are necessary, though, at the very least.
Fred.
