The 1999-2003 Chrysler Concorde/Dodge Intrepid Environmental Features

Vehicle Emission Controls

Both new Concorde and Intrepid engines were designed to meet year 2000 exhaust emission regulations by minimizing the output of pollutants at the engine, thereby limiting the demand on downstream control devices. Both engines produced 30 percent less hydrocarbon (unburned fuel) emissions than their 1997 predecessors. In most states and foreign markets, the engines met the federal Tier 1 emission standards. In California and states that adopted their standards, the engines met more stringent TLEV (Transition Low Emission Vehicle) emission standards by using more effective (and expensive) catalytic converters. Both engines were available in both markets.

The emission control system included the following features:

  • Dual, close-coupled catalytic converters reached operating temperature faster than those in any prior Chrysler emission system because of their proximity to the engine [webmaster note: you can see it under the hood!]. This resulted in a 30 percent reduction of mass over the previous three-converter system. The federal configuration also used 30-40 percent less precious metal than the prior system. To reduce underhood space requirements, these converters used a substrate of high-grade stainless steel foil on which the catalytic coating was applied. The stainless steel foil was less bulky than available ceramic substrates
  • The top piston ring was 45 percent closer to the piston crown than on prior Concorde and Intrepid engines. This minimized the volume of the crevice where fuel does not burn and may be expelled to the atmosphere as a pollutant if not oxidized by the catalytic converter. Because the top piston ring was closer to the combustion process, it operated at a higher temperature and therefore, the top piston ring groove was anodized to prevent the ring from sticking
  • Nitrogen oxide emissions were reduced by using recirculated exhaust to thoroughly mix the incoming charge of fuel and air in the high turbulence combustion chambers. The intake port and valve configuration imparted the turbulence by making the fuel, air and exhaust gas tumble as they enter the cylinder, resulting in very efficient combustion
  • Coil-on plug ignition provided individual, high-energy secondary coils which were connected directly to each spark plug, providing more than a 28 percent power increase over the former direct ignition system (DIS). This allowed for improved ignition of the lean mixtures in the high turbulance combustion chambers, which were necessary for reduced emissions. In the 3.2-liter engine, the coils provided 60 percent more energy during cold starts and warm-up, allowing for a leaner (and cleaner) fuel and air mixture. The combustion process was also hotter, producing the hot exhaust gasses necessary to quickly heat the catalysts to get them to peak operating temperature quickly
  • Exhaust ports were as small as possible without adversely affecting power to quickly heat the catalytic converters to operating temperature. Because heat in the exhaust stream transferred to the head as exhaust flows through the ports, reducing port size reduced the surface area to which the heat can transfer. Small ports also resulted in high velocity flow, leaving little time for heat transfer.
  • Short cylinder bore water jackets contributed to more complete combustion. Water jacket coverage had been reduced nearly 50 percent-from 1.5 times the piston stroke to only 80 percent, providing a more uniform temperature throughout the piston stroke. The greatest amount of heat was created at the top of the piston stroke and the temperature in the cylinder diminished as the mixture expanded and the piston was driven downward. By limiting the water jacket to the top portion of the cylinder, the lower portion stayed hotter. This allowed combustion to continue longer because the cylinder did not quench the flame by cooling the combustion products. Computational Fluid Dynamics (CFD) showed how to reduce coolant volume for higher temperatures without causing localized overheating
  • Fuel injectors were mounted directly in the cylinder head allowing for a very wide spray pattern of injected fuel, without wetting the cylinder walls. (Wetting increases emissions by leaving unburned fuel in the chamber). The wide spray produced very fine atomization of the incoming fuel charge allowing for a very complete burn, thus reducing hydrocarbon emissions
  • A synchronous fuel injection timing ensured that fuel arrives when the intake valves are open, mixing thoroughly with the incoming air
  • LS EGR (linear solenoid exhaust gas recirculation) used a linear solenoid valve controlled by the Power Train Control Module (PCM) to provide the precise amount exhaust flow to the intake manifold, which was needed for optimum reduction of nitrogen oxide exhaust emissions. EGR flow to individual cylinders was mapped and fine tuned using CFD
  • Inlet-side, bypass-type thermostats provided a smoother introduction of coolant from the radiator to the block during warm-up compared with an outlet-side system. This allowed closer control of fuel flow and ignition timing, which was tied to coolant temperature during warm-up. Because it immediately sensed the temperature of the incoming coolant, it only allowed short bursts until the radiator and block temperatures stabilize. An outlet-side thermostat tended to permit large bursts of low-temperature coolant into the block during warm-up because the lower temperature was not sensed until this flow reached the thermostat. This chilled the cylinders briefly, sometimes causing the control system to return to a richer fuel mixture that increased emissions and reduced fuel economy
  • Quad oxygen sensors mounted in the front and back of each catalytic converter (a total of four) provided precise side-to-side control of fuel injection rate and monitor catalytic converter efficiency as required by emission control standards. In addition, they enabled fine tuning of the fuel-to-air ratio, keeping tail pipe emissions low throughout the life of the vehicle
  • Low-mass exhaust manifolds constructed of lightweight, thin-wall cast iron absorb little heat from the exhaust stream, speeding catalytic converter warm up. Faster catalyst warm-up reduced emissions
  • Differential intake and exhaust valve height on the 2.7-liter engine reduced emissions, because the exhaust valves were higher in the combustion chambers than the intake valves. This allowed a vortex of condensing unburned fuel vapor to be pushed up the cylinder by the piston during the exhaust stroke instead of the exhaust stream. This remnant remained in the cylinder to be burned during the next cycle, reducing emissions that must be treated by the catalytic converter
  • A combined charge-air temperature and manifold absolute pressure sensor (T-MAP) on the 3.2-liter engine gave more accurate temperature readings than the prior charge sensor location

On-Board Diagnostics - Evaporative System Leak Detection

A leak detection system, similar to that used on other Chrysler vehicles since 1996, mounted close to the fuel tank on cars meeting California emission requirements. The leak detection system included a leak detection pump that lightly pressurizes the entire fuel supply system periodically to verify that vapor was not escaping. If vapor leakage exceeded the flow through a 0.040-in. (1mm) orifice, the OBD II (on-board diagnostic system) turned on the 'CHECK ENGINE' light.

Environmentally Friendly Materials and Processes

The following environmentally friendly materials and processes were used on the 1998 Concorde and Intrepid:

  • The RRIM fascias used on Concorde included 5 percent post-consumer recycled material.
  • The molded urethane steering wheel rim used water, rather than CFCs, as the expansion agent to help protect the atmosphere.
  • New engine coolant formulation used 100 percent post consumer ethylene glycol as a base.
  • All base coat paint was water-borne, greatly reducing the amount of VOCs (volatile organic compounds) vented to the atmosphere. The electro-coat primer remained a low-VOC water-borne material.
  • New intake manifolds on all engines were made from recyclable PA 66 nylon.
  • Air induction system components, including the air cleaner housing were made of recyclable PA 66 nylon or polypropylene.

As on the prior Concorde and Intrepid, the substrate of the interior roof system was made from sound insulating AcoustiCor®, which was primarily recycled polyethylene terepthalate (PET) soft drink bottles reinforced with glass fiber. A further refinement of the recycling process was the recycling of the AcoustiCor headliners into a new material called EcoCor® for which applications were sought.

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