All about the LH2 Northstar

Non-repair car talk
Post Reply
kevm14
Posts: 15241
Joined: Wed Oct 23, 2013 10:28 pm

All about the LH2 Northstar

Post by kevm14 »

http://www.autospeed.com/cms/article.ht ... -V8&A=1569

That is a lot of info. The HP and torque spec is low by 5 for each for some reason.

Forged crank and rods. Nice.

No wonder why the 04-05 ECMs cannot be tuned.
Engine Control Module

The ECM is a 16-bit, 24 MHz microprocessor, high memory control unit designed to integrate the engine's infinitely variable valve timing (VVT) for both intake and exhaust valve trains, Electronic Throttle Control (ETC), and closed coupled catalysts for meeting emission requirements without secondary emission control systems.
The controller is also designed for a GM LAN communication protocol speed of 500 kbit/second and has a 185-pin connection system for enhanced input/output capability. (Currently, 120-pin systems are more the norm.) GM's LAN communication protocol is an adaptation of the industry-wide CAN-Bus (control area network).

Other ECM functions include:
Individual cylinder knock control and fuel control - it controls fuel mixture richness/leanness at each cylinder to keep it at the optimal stoichiometric ratio, rather than averaging all 8 cylinders or by cylinder bank, the typical approaches.
Full Onboard Diagnostic (OBD) II capability without a secondary air pump (the Northstar 4.6-litre engine does not need a secondary pump for emission control).
Linear lambda control, wide ranging air/fuel sensing for more precise control to meet emission requirements - typically an analog oxygen sensor is used, which is slower and less exacting.
Engine protection functions - including "camel mode," which allows the engine to continue running for another 50 miles before shutting down should it lose all coolant by only operating four cylinders at a time so it runs cooler. The ECM will also shut down the ignition system if the car doesn't start within 14 seconds, assuming a possible major mechanical problem.

Engine off natural vacuum (EONV) diagnostics for evaporative emission leak detection.
Comprehensive exhaust gas temperature model - exhaust gas temperature is used as a basis for adjusting fuel control: as the temperature increases the fuel control is adjusted accordingly to protect the converter from melting.

The ECM was co-developed by Siemens VDO Automotive and GM Powertrain.
Because of that last part I assume.

It has individual cylinder knock and fuel control.
Attachments
Anatomy of the LH2 Northstar.pdf
(767.84 KiB) Downloaded 21 times
kevm14
Posts: 15241
Joined: Wed Oct 23, 2013 10:28 pm

Re: All about the LH2 Northstar

Post by kevm14 »

This might be an interesting one to pull if I can figure out a free way.

https://www.sae.org/publications/techni ... 3-01-0922/
2003-03-03
The Next Generation Northstar DOHC 4.6L V8 Engine with Four-Cam Continuously Variable Valve Timing for Cadillac 2003-01-0922

A new generation Northstar DOHC V8 engine has been developed for a new family of rear-wheel-drive (RWD) Cadillac vehicles. The new longitudinal engine architecture includes strategically selected technologies to enable a higher level of performance and refinement. These technologies include four-cam continuously variable valve timing, low restriction intake and exhaust manifolds and cylinder head ports, a steel crankshaft, electronic throttle control, and close-coupled catalysts. Additional design features beyond those required for RWD include optimized block ribbing, improved coolant flow, and a newly developed lubrication and ventilation system for high-speed operation and high lateral acceleration. This new design results in improved performance over the entire operating range, lower emissions, improved fuel economy, improved operating refinement, and reduced noise/vibration/harshness (NVH).

Simultaneous engineering and extensive use of math-based 3D modeling and analysis were the cornerstones of the project from inception. This reduced development time and the amount of required development hardware while ensuring the highest reliability for the new engine. Manufacturing implementation required the maximum possible commonality with the transversely mounted front-wheel-drive (FWD) Northstar engine.

DOI: https://doi.org/10.4271/2003-01-0922
Citation: Bonello, M., Cremonesi, J., Davis, R., Prior, G. et al., "The Next Generation Northstar DOHC 4.6L V8 Engine with Four-Cam Continuously Variable Valve Timing for Cadillac," SAE Technical Paper 2003-01-0922, 2003, https://doi.org/10.4271/2003-01-0922.
Download Citation
Author(s): Michael J. Bonello, James D. Cremonesi, Richard S. Davis, Gregory P. Prior, John C. Zinser
Affiliated: General Motors Corporation
Pages: 26
Event: SAE 2003 World Congress & Exhibition
ISSN: 0148-7191
e-ISSN: 2688-3627
Also in: New SI Engine and Component Design-SP-1747, Variable Valvetrain System Technology-PT-122, Design of Racing and High-Performance Engines 1998-2003-PT-100
Suggested alternate title: We fixed the head gaskets. lol
Post Reply